[PATCH v2 00/10] Add support for Apple Silicon DockChannel internal keyboards

[PATCH v2 00/10] Add support for Apple Silicon DockChannel internal keyboards

[Michael Reeves via B4 Relay]

This series introduces support for the internal keyboards on Apple
Silicon M2 and M3 MacBook models.

On these platforms, built-in input devices are managed by a dedicated
coprocessor running an RTKit-based operating system. Communication
between this coprocessor and the main processor is carried out over a
low-latency hardware byte FIFO interface called DockChannel.

To support this input path, the series introduces a few new components:
- An apple-dockchannel mailbox driver to handle the low-level
  byte-stream FIFO.
- A DockChannel HID transport driver (apple-hid) that boots the
  coprocessor using the RTKit framework and encapsulates the HID
  protocol over the mailbox.
- Minor additions to the apple-rtkit and hid-apple drivers to support
  the TraceKit endpoint and integrate the keyboards into the existing
  input-quirks framework.
- Devicetree bindings and DTS updates to describe the nodes on M2 and
  M3 laptops.

The transport driver is based on an original out-of-tree implementation
by Hector Martin, but it has been significantly rewritten for upstream
inclusion to use the standard Linux mailbox framework and align better
with upstream HID design patterns and reduce reliance on hacks.

While the coprocessor manages both the keyboard and the trackpad, this
series only enables keyboard support. The keyboard can be initialised
without loading external firmware, whereas the trackpad requires
firmware. Trackpad support will be submitted in a subsequent series
once these base transport layers are established.

Tested on: MacBook Air M3 (J613).

Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>

Changes in v2:
- Link to v1: https://lore.kernel.org/asahi/20260630-apple-mtp-keyboard-final-v1-0-506d936a1707@gmail.com/
- Rebase onto latest upstream and add M3 Pro/Max device-tree support.
- Use an optional STM node to decide whether to wait for device IDs
  (suggested by Yureka Lilian).
- Rename bindings to match the t8112 fallback (suggested by Conor Dooley).
- Fix FIFO MMIO write width (suggested by Yureka Lilian) and run mailbox
  interrupt handling in the IRQ thread.
- Remove the duplicate report fixup (suggested by Sasha Finkelstein)
  and redundant HID dependency (suggested by Julian Braha).
- Fix teardown and the missing HID stop callback; simplify interface lookup.

---
Michael Reeves (9):
      dt-bindings: mailbox: apple: Add M3 ASC mailbox compatibles
      dt-bindings: mailbox: apple: Add DockChannel mailbox
      dt-bindings: iommu: apple,dart: Add M3 compatibles
      dt-bindings: input: apple: Add DockChannel HID transport
      mailbox: apple: Add DockChannel FIFO controller
      HID: apple: Add support for DockChannel HID keyboards
      HID: apple: Add DockChannel HID transport driver
      arm64: dts: apple: Add MTP DockChannel HID nodes
      arm64: dts: apple: Enable DockChannel HID on M2 and M3 laptops

Sasha Finkelstein (1):
      soc: apple: rtkit: Add tracekit endpoint

 .../input/apple,t8112-dockchannel-hid.yaml         |  104 ++
 .../devicetree/bindings/iommu/apple,dart.yaml      |    6 +-
 .../devicetree/bindings/mailbox/apple,mailbox.yaml |    3 +
 .../bindings/mailbox/apple,t8112-dockchannel.yaml  |   77 ++
 MAINTAINERS                                        |    5 +
 arch/arm64/boot/dts/apple/t602x-die0.dtsi          |   46 +
 arch/arm64/boot/dts/apple/t602x-j414-j416.dtsi     |   29 +
 arch/arm64/boot/dts/apple/t6030.dtsi               |   46 +
 arch/arm64/boot/dts/apple/t6031-die0.dtsi          |   46 +
 arch/arm64/boot/dts/apple/t603x-j514-j516.dtsi     |   24 +
 arch/arm64/boot/dts/apple/t8112-j413.dts           |   24 +
 arch/arm64/boot/dts/apple/t8112-j415.dts           |   24 +
 arch/arm64/boot/dts/apple/t8112-j493.dts           |   26 +-
 arch/arm64/boot/dts/apple/t8112.dtsi               |   46 +
 arch/arm64/boot/dts/apple/t8122-j504.dts           |   26 +
 arch/arm64/boot/dts/apple/t8122-j613.dts           |   27 +
 arch/arm64/boot/dts/apple/t8122-j615.dts           |   27 +
 arch/arm64/boot/dts/apple/t8122.dtsi               |   47 +
 drivers/hid/Kconfig                                |    2 +
 drivers/hid/Makefile                               |    2 +
 drivers/hid/dockchannel/Kconfig                    |   14 +
 drivers/hid/dockchannel/Makefile                   |    3 +
 drivers/hid/dockchannel/apple-hid.c                | 1157 ++++++++++++++++++++
 drivers/hid/hid-apple.c                            |  117 +-
 drivers/mailbox/Kconfig                            |   12 +
 drivers/mailbox/Makefile                           |    2 +
 drivers/mailbox/apple-dockchannel.c                |  371 +++++++
 drivers/soc/apple/rtkit.c                          |    2 +
 include/linux/hid.h                                |    1 +
 include/linux/mailbox/apple-dockchannel.h          |   29 +
 30 files changed, 2297 insertions(+), 48 deletions(-)
---
base-commit: 5dd1818b15d98d4a20806cd00b1b40320b06004f
change-id: 20260629-apple-mtp-keyboard-final-91cb5a6ff4fc

Best regards,
-- 
Michael Reeves <michael.reeves077@gmail.com>

[PATCH v2 01/10] dt-bindings: mailbox: apple: Add M3 ASC mailbox compatibles

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

Add the t8122, t6030 and t6031 ASC mailbox compatibles used by the
MTP coprocessor on M3, M3 Pro and M3 Max SoCs. They share the existing
ASC v4 mailbox interface.

Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
---
 Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml b/Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
index 28985cc62..9a6dfb0b2 100644
--- a/Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
+++ b/Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
@@ -30,8 +30,11 @@ properties:
           - enum:
               - apple,t8103-asc-mailbox
               - apple,t8112-asc-mailbox
+              - apple,t8122-asc-mailbox
               - apple,t6000-asc-mailbox
               - apple,t6020-asc-mailbox
+              - apple,t6030-asc-mailbox
+              - apple,t6031-asc-mailbox
           - const: apple,asc-mailbox-v4
 
       - description:

-- 
2.55.0

[PATCH v2 02/10] dt-bindings: mailbox: apple: Add DockChannel mailbox

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

DockChannel is a FIFO and interrupt block used by Apple coprocessors
to exchange byte-stream traffic with the AP.

Describe it as a mailbox provider so HID and future serial clients can
use the common mailbox API.

Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../bindings/mailbox/apple,t8112-dockchannel.yaml  | 77 ++++++++++++++++++++++
 MAINTAINERS                                        |  1 +
 2 files changed, 78 insertions(+)

diff --git a/Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml b/Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml
new file mode 100644
index 000000000..dd2fdfa01
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml
@@ -0,0 +1,77 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/apple,t8112-dockchannel.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple DockChannel FIFO Mailbox
+
+maintainers:
+  - Michael Reeves <michael.reeves077@gmail.com>
+
+description:
+  DockChannel is a hardware FIFO and interrupt block used on Apple SoCs for
+  low-latency byte stream communication with co-processors.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: apple,t8112-dockchannel
+      - items:
+          - enum:
+              - apple,t6020-dockchannel
+              - apple,t6030-dockchannel
+              - apple,t6031-dockchannel
+              - apple,t8122-dockchannel
+          - const: apple,t8112-dockchannel
+
+  reg:
+    items:
+      - description: Interrupt control registers
+      - description: FIFO configuration registers
+      - description: FIFO data registers
+
+  reg-names:
+    items:
+      - const: irq
+      - const: config
+      - const: data
+
+  interrupts:
+    maxItems: 1
+
+  "#mbox-cells":
+    const: 0
+
+  nonposted-mmio: true
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/apple-aic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        mailbox@24eb14000 {
+            compatible = "apple,t8112-dockchannel";
+            reg = <0x2 0x4eb14000 0x0 0x4000>,
+                  <0x2 0x4eb30000 0x0 0x4000>,
+                  <0x2 0x4eb34000 0x0 0x4000>;
+            reg-names = "irq", "config", "data";
+            interrupt-parent = <&aic>;
+            interrupts = <AIC_IRQ 850 IRQ_TYPE_LEVEL_HIGH>;
+            #mbox-cells = <0>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 3b2eb2a7a..0183c3e1c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2643,6 +2643,7 @@ F:	Documentation/devicetree/bindings/iommu/apple,dart.yaml
 F:	Documentation/devicetree/bindings/iommu/apple,sart.yaml
 F:	Documentation/devicetree/bindings/leds/backlight/apple,dwi-bl.yaml
 F:	Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
+F:	Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml
 F:	Documentation/devicetree/bindings/mfd/apple,smc.yaml
 F:	Documentation/devicetree/bindings/net/bluetooth/brcm,bcm4377-bluetooth.yaml
 F:	Documentation/devicetree/bindings/nvme/apple,nvme-ans.yaml

-- 
2.55.0

[PATCH v2 03/10] dt-bindings: iommu: apple,dart: Add M3 compatibles

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

Add the t8122, t6030 and t6031 DART compatibles used by the MTP
coprocessor on M3, M3 Pro and M3 Max SoCs, with the t8110 fallback.

Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
---
 Documentation/devicetree/bindings/iommu/apple,dart.yaml | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/iommu/apple,dart.yaml b/Documentation/devicetree/bindings/iommu/apple,dart.yaml
index 47ec7fa52..efadec786 100644
--- a/Documentation/devicetree/bindings/iommu/apple,dart.yaml
+++ b/Documentation/devicetree/bindings/iommu/apple,dart.yaml
@@ -29,7 +29,11 @@ properties:
           - apple,t8110-dart
           - apple,t6000-dart
       - items:
-          - const: apple,t6020-dart
+          - enum:
+              - apple,t6020-dart
+              - apple,t6030-dart
+              - apple,t6031-dart
+              - apple,t8122-dart
           - const: apple,t8110-dart
 
   reg:

-- 
2.55.0

[PATCH v2 04/10] dt-bindings: input: apple: Add DockChannel HID transport

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

Apple internal keyboards and trackpads behind MTP are exposed through a
DockChannel HID transport.

Add the client binding tying together the RTKit ASC mailbox,
DockChannel mailbox, and MTP DART. The keyboard child can provide the
HID country code used by hid-apple to distinguish layout variants.

Describe the optional STM child, which supplies the device identifiers
and serial number shared by the HID interfaces.

Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>

---
Conor's v1 Reviewed-by is not carried forward because v2 adds the STM binding.
---
 .../input/apple,t8112-dockchannel-hid.yaml         | 104 +++++++++++++++++++++
 MAINTAINERS                                        |   1 +
 2 files changed, 105 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/apple,t8112-dockchannel-hid.yaml b/Documentation/devicetree/bindings/input/apple,t8112-dockchannel-hid.yaml
new file mode 100644
index 000000000..c25e072b6
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/apple,t8112-dockchannel-hid.yaml
@@ -0,0 +1,104 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/apple,t8112-dockchannel-hid.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple DockChannel HID Transport
+
+maintainers:
+  - Michael Reeves <michael.reeves077@gmail.com>
+
+description:
+  HID transport for keyboard and trackpad devices connected via the
+  DockChannel FIFO mailbox on Apple Silicon SoCs. The endpoint includes a
+  small RTKit coprocessor called MTP which must be booted before the HID
+  transport becomes available.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: apple,t8112-dockchannel-hid
+      - items:
+          - enum:
+              - apple,t6020-dockchannel-hid
+              - apple,t6030-dockchannel-hid
+              - apple,t6031-dockchannel-hid
+              - apple,t8122-dockchannel-hid
+          - const: apple,t8112-dockchannel-hid
+
+  reg:
+    items:
+      - description: Coprocessor ASC registers
+      - description: Coprocessor SRAM/mailbox registers
+
+  reg-names:
+    items:
+      - const: coproc-asc
+      - const: coproc-sram
+
+  mboxes:
+    items:
+      - description: ASC mailbox used for RTKit control
+      - description: DockChannel FIFO mailbox used for HID packets
+
+  mbox-names:
+    items:
+      - const: asc
+      - const: dockchannel
+
+  iommus:
+    maxItems: 1
+
+  stm:
+    type: object
+    description:
+      STM interface providing the vendor, product and version identifiers
+      and serial number shared by the HID devices. When present, the host
+      must query this interface before registering the keyboard.
+    additionalProperties: false
+
+  keyboard:
+    type: object
+    properties:
+      hid-country-code:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          HID country code for the keyboard layout variant.
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - mboxes
+  - mbox-names
+  - iommus
+
+additionalProperties: false
+
+examples:
+  - |
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        hid@24e400000 {
+            compatible = "apple,t8112-dockchannel-hid";
+            reg = <0x2 0x4e400000 0x0 0x4000>,
+                  <0x2 0x4ec00000 0x0 0x100000>;
+            reg-names = "coproc-asc", "coproc-sram";
+            mboxes = <&mtp_mbox>, <&mtp_dockchannel>;
+            mbox-names = "asc", "dockchannel";
+            iommus = <&mtp_dart 1>;
+
+            stm {
+            };
+
+            keyboard {
+                hid-country-code = <0>;
+            };
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 0183c3e1c..7fe2ebb5e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2637,6 +2637,7 @@ F:	Documentation/devicetree/bindings/gpio/apple,smc-gpio.yaml
 F:	Documentation/devicetree/bindings/gpu/apple,agx.yaml
 F:	Documentation/devicetree/bindings/hwmon/apple,smc-hwmon.yaml
 F:	Documentation/devicetree/bindings/i2c/apple,i2c.yaml
+F:	Documentation/devicetree/bindings/input/apple,t8112-dockchannel-hid.yaml
 F:	Documentation/devicetree/bindings/input/touchscreen/apple,z2-multitouch.yaml
 F:	Documentation/devicetree/bindings/interrupt-controller/apple,*
 F:	Documentation/devicetree/bindings/iommu/apple,dart.yaml

-- 
2.55.0

[PATCH v2 05/10] mailbox: apple: Add DockChannel FIFO controller

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

DockChannel is a hardware FIFO used by Apple coprocessors for
low-latency byte-stream communication with the AP.

Add a mailbox controller that preallocates RX storage, tracks IRQ
enable state in software, and reports TX completion from the TX-empty
interrupt.

Reject messages larger than the FIFO and return -EBUSY while the
previous message is still pending. This keeps the provider usable for
future small-message clients such as serial transports without a TX
worker.

Handle RX and TX interrupts in a thread so mailbox callbacks and locking
run outside hard-IRQ context.

Co-developed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
---
 MAINTAINERS                               |   2 +
 drivers/mailbox/Kconfig                   |  12 +
 drivers/mailbox/Makefile                  |   2 +
 drivers/mailbox/apple-dockchannel.c       | 371 ++++++++++++++++++++++++++++++
 include/linux/mailbox/apple-dockchannel.h |  29 +++
 5 files changed, 416 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 7fe2ebb5e..e5be5934c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2677,6 +2677,7 @@ F:	drivers/input/touchscreen/apple_z2.c
 F:	drivers/iommu/apple-dart.c
 F:	drivers/iommu/io-pgtable-dart.c
 F:	drivers/irqchip/irq-apple-aic.c
+F:	drivers/mailbox/apple-dockchannel.c
 F:	drivers/mfd/macsmc.c
 F:	drivers/nvme/host/apple.c
 F:	drivers/nvmem/apple-efuses.c
@@ -2695,6 +2696,7 @@ F:	drivers/video/backlight/apple_dwi_bl.c
 F:	drivers/watchdog/apple_wdt.c
 F:	include/dt-bindings/interrupt-controller/apple-aic.h
 F:	include/dt-bindings/pinctrl/apple.h
+F:	include/linux/mailbox/apple-dockchannel.h
 F:	include/linux/mfd/macsmc.h
 F:	include/linux/soc/apple/*
 F:	include/uapi/drm/asahi_drm.h
diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index ab869769e..503d3286f 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -36,6 +36,18 @@ config ARM_MHU_V3
 	  that provides different means of transports: supported extensions
 	  will be discovered and possibly managed at probe-time.
 
+config APPLE_DOCKCHANNEL
+	tristate "Apple DockChannel FIFO mailbox"
+	depends on ARCH_APPLE || COMPILE_TEST
+	depends on HAS_IOMEM
+	depends on OF
+	help
+	  DockChannel is a hardware FIFO used on Apple Silicon SoCs for
+	  communication between the application processor and co-processors.
+	  This driver exposes DockChannel FIFOs through the mailbox framework.
+
+	  Say Y here if you have an M2 or later Apple MacBook.
+
 config AST2700_MBOX
 	tristate "ASPEED AST2700 IPC driver"
 	depends on ARCH_ASPEED || COMPILE_TEST
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 45dc59bb3..61b15fe45 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -11,6 +11,8 @@ obj-$(CONFIG_ARM_MHU_V2)	+= arm_mhuv2.o
 
 obj-$(CONFIG_ARM_MHU_V3)	+= arm_mhuv3.o
 
+obj-$(CONFIG_APPLE_DOCKCHANNEL)	+= apple-dockchannel.o
+
 obj-$(CONFIG_AST2700_MBOX)	+= ast2700-mailbox.o
 
 obj-$(CONFIG_CV1800_MBOX)	+= cv1800-mailbox.o
diff --git a/drivers/mailbox/apple-dockchannel.c b/drivers/mailbox/apple-dockchannel.c
new file mode 100644
index 000000000..d0a66e1b7
--- /dev/null
+++ b/drivers/mailbox/apple-dockchannel.c
@@ -0,0 +1,371 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple DockChannel mailbox controller
+ *
+ * Copyright The Asahi Linux Contributors
+ *
+ * DockChannel is a byte FIFO used by Apple co-processors. This driver exposes a
+ * single FIFO pair as a Linux mailbox channel and moves payload bytes with PIO.
+ * There is no DMA involved, so relaxed MMIO accessors are sufficient for the
+ * FIFO accesses themselves.
+ */
+
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mailbox/apple-dockchannel.h>
+#include <linux/mailbox_controller.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/unaligned.h>
+
+#define APPLE_DOCKCHANNEL_FIFO_SIZE	0x800
+
+#define IRQ_MASK			0x0
+#define IRQ_FLAG			0x4
+
+#define IRQ_TX				BIT(2)
+#define IRQ_RX				BIT(3)
+
+#define CONFIG_TX_THRESH		0x0
+#define CONFIG_RX_THRESH		0x4
+
+#define DATA_TX8			0x4
+#define DATA_TX32			0x10
+#define DATA_TX_FREE			0x14
+#define DATA_RX8			0x1c
+#define DATA_RX32			0x28
+#define DATA_RX_COUNT			0x2c
+
+struct apple_dockchannel {
+	struct device *dev;
+	struct mbox_controller controller;
+	struct mbox_chan chan;
+
+	void __iomem *irq_base;
+	void __iomem *config_base;
+	void __iomem *data_base;
+	int irq;
+
+	spinlock_t lock; /* protects IRQ mask and TX state */
+	u32 irq_mask;
+
+	const u8 *tx_buf;
+	size_t tx_len;
+	size_t tx_pos;
+	bool tx_active;
+
+	u8 rx_buf[APPLE_DOCKCHANNEL_FIFO_SIZE];
+};
+
+static void apple_dockchannel_irq_update(struct apple_dockchannel *dc,
+					 u32 bits, bool enable)
+{
+	if (enable)
+		dc->irq_mask |= bits;
+	else
+		dc->irq_mask &= ~bits;
+	writel_relaxed(dc->irq_mask, dc->irq_base + IRQ_MASK);
+}
+
+static void apple_dockchannel_irq_enable(struct apple_dockchannel *dc, u32 bits)
+{
+	/*
+	 * IRQ_FLAG is write-to-clear. Clear stale latched flags before
+	 * unmasking so the next interrupt reflects current FIFO state.
+	 */
+	writel_relaxed(bits, dc->irq_base + IRQ_FLAG);
+	apple_dockchannel_irq_update(dc, bits, true);
+}
+
+static void apple_dockchannel_irq_disable(struct apple_dockchannel *dc, u32 bits)
+{
+	apple_dockchannel_irq_update(dc, bits, false);
+}
+
+static bool apple_dockchannel_tx_empty(struct apple_dockchannel *dc)
+{
+	return readl_relaxed(dc->data_base + DATA_TX_FREE) ==
+	       APPLE_DOCKCHANNEL_FIFO_SIZE;
+}
+
+static void apple_dockchannel_write_pending(struct apple_dockchannel *dc)
+{
+	size_t left = dc->tx_len - dc->tx_pos;
+	const u8 *p = dc->tx_buf + dc->tx_pos;
+
+	while (left) {
+		size_t avail;
+		size_t block;
+
+		avail = readl_relaxed(dc->data_base + DATA_TX_FREE);
+		if (!avail)
+			break;
+
+		block = min(left, avail);
+
+		while (block >= sizeof(u32)) {
+			writel_relaxed(get_unaligned_le32(p),
+				       dc->data_base + DATA_TX32);
+			p += sizeof(u32);
+			left -= sizeof(u32);
+			block -= sizeof(u32);
+		}
+
+		while (block) {
+			writel_relaxed(*p++, dc->data_base + DATA_TX8);
+			left--;
+			block--;
+		}
+	}
+
+	dc->tx_pos = dc->tx_len - left;
+}
+
+static void apple_dockchannel_read(struct apple_dockchannel *dc, void *buf,
+				   size_t count)
+{
+	u8 *p = buf;
+	size_t left = count;
+
+	while (left >= sizeof(u32)) {
+		put_unaligned_le32(readl_relaxed(dc->data_base + DATA_RX32), p);
+		p += sizeof(u32);
+		left -= sizeof(u32);
+	}
+
+	while (left) {
+		/*
+		 * The byte FIFO register returns the byte in bits [15:8] on
+		 * these instances.
+		 */
+		*p++ = readl_relaxed(dc->data_base + DATA_RX8) >> 8;
+		left--;
+	}
+}
+
+static int apple_dockchannel_send_data(struct mbox_chan *chan, void *data)
+{
+	struct apple_dockchannel *dc = chan->con_priv;
+	struct apple_dockchannel_msg *msg = data;
+	unsigned long flags;
+
+	if (!msg || !msg->data || !msg->len)
+		return -EINVAL;
+
+	if (msg->len > APPLE_DOCKCHANNEL_FIFO_SIZE)
+		return -EMSGSIZE;
+
+	spin_lock_irqsave(&dc->lock, flags);
+
+	if (dc->tx_active || !apple_dockchannel_tx_empty(dc)) {
+		spin_unlock_irqrestore(&dc->lock, flags);
+		return -EBUSY;
+	}
+
+	dc->tx_buf = msg->data;
+	dc->tx_len = msg->len;
+	dc->tx_pos = 0;
+	dc->tx_active = true;
+
+	apple_dockchannel_write_pending(dc);
+	writel_relaxed(APPLE_DOCKCHANNEL_FIFO_SIZE,
+		       dc->config_base + CONFIG_TX_THRESH);
+	apple_dockchannel_irq_enable(dc, IRQ_TX);
+
+	spin_unlock_irqrestore(&dc->lock, flags);
+
+	return 0;
+}
+
+static int apple_dockchannel_startup(struct mbox_chan *chan)
+{
+	struct apple_dockchannel *dc = chan->con_priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dc->lock, flags);
+	/*
+	 * The mailbox framework has no per-client RX threshold. Use byte
+	 * granularity because UART-style DockChannel clients require it.
+	 */
+	writel_relaxed(1, dc->config_base + CONFIG_RX_THRESH);
+	apple_dockchannel_irq_enable(dc, IRQ_RX);
+	spin_unlock_irqrestore(&dc->lock, flags);
+
+	enable_irq(dc->irq);
+
+	return 0;
+}
+
+static void apple_dockchannel_shutdown(struct mbox_chan *chan)
+{
+	struct apple_dockchannel *dc = chan->con_priv;
+	unsigned long flags;
+
+	disable_irq(dc->irq);
+
+	spin_lock_irqsave(&dc->lock, flags);
+	apple_dockchannel_irq_disable(dc, IRQ_TX | IRQ_RX);
+	dc->tx_active = false;
+	spin_unlock_irqrestore(&dc->lock, flags);
+}
+
+static const struct mbox_chan_ops apple_dockchannel_mbox_ops = {
+	.send_data = apple_dockchannel_send_data,
+	.startup = apple_dockchannel_startup,
+	.shutdown = apple_dockchannel_shutdown,
+};
+
+static irqreturn_t apple_dockchannel_irq_thread(int irq, void *data)
+{
+	struct apple_dockchannel *dc = data;
+	unsigned long irqflags;
+	u32 flags;
+	u32 pending;
+	bool tx_done = false;
+
+	flags = readl_relaxed(dc->irq_base + IRQ_FLAG);
+
+	spin_lock_irqsave(&dc->lock, irqflags);
+
+	pending = flags & dc->irq_mask & (IRQ_TX | IRQ_RX);
+	if (!pending)
+		goto out_unlock_none;
+
+	if (pending & IRQ_TX) {
+		if (apple_dockchannel_tx_empty(dc)) {
+			apple_dockchannel_irq_disable(dc, IRQ_TX);
+			tx_done = dc->tx_active;
+			dc->tx_active = false;
+		} else {
+			pending &= ~IRQ_TX;
+		}
+	}
+
+	writel_relaxed(pending, dc->irq_base + IRQ_FLAG);
+
+	spin_unlock_irqrestore(&dc->lock, irqflags);
+
+	if (tx_done)
+		mbox_chan_txdone(&dc->chan, 0);
+
+	if (!(pending & IRQ_RX))
+		return pending ? IRQ_HANDLED : IRQ_NONE;
+
+	for (;;) {
+		struct apple_dockchannel_msg msg;
+		size_t avail;
+
+		avail = readl_relaxed(dc->data_base + DATA_RX_COUNT);
+		if (!avail)
+			break;
+
+		avail = min_t(size_t, avail, APPLE_DOCKCHANNEL_FIFO_SIZE);
+
+		apple_dockchannel_read(dc, dc->rx_buf, avail);
+
+		msg.data = dc->rx_buf;
+		msg.len = avail;
+		mbox_chan_received_data(&dc->chan, &msg);
+	}
+
+	return IRQ_HANDLED;
+
+out_unlock_none:
+	spin_unlock_irqrestore(&dc->lock, irqflags);
+
+	if (flags & (IRQ_TX | IRQ_RX))
+		writel_relaxed(flags & (IRQ_TX | IRQ_RX),
+			       dc->irq_base + IRQ_FLAG);
+
+	return IRQ_NONE;
+}
+
+static struct mbox_chan *
+apple_dockchannel_of_xlate(struct mbox_controller *mbox,
+			   const struct of_phandle_args *spec)
+{
+	if (spec->args_count != 0)
+		return ERR_PTR(-EINVAL);
+
+	return &mbox->chans[0];
+}
+
+static int apple_dockchannel_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct apple_dockchannel *dc;
+	int ret;
+
+	dc = devm_kzalloc(dev, sizeof(*dc), GFP_KERNEL);
+	if (!dc)
+		return -ENOMEM;
+
+	dc->dev = dev;
+	spin_lock_init(&dc->lock);
+	platform_set_drvdata(pdev, dc);
+
+	dc->irq_base = devm_platform_ioremap_resource_byname(pdev, "irq");
+	if (IS_ERR(dc->irq_base))
+		return PTR_ERR(dc->irq_base);
+
+	dc->config_base = devm_platform_ioremap_resource_byname(pdev, "config");
+	if (IS_ERR(dc->config_base))
+		return PTR_ERR(dc->config_base);
+
+	dc->data_base = devm_platform_ioremap_resource_byname(pdev, "data");
+	if (IS_ERR(dc->data_base))
+		return PTR_ERR(dc->data_base);
+
+	writel_relaxed(0, dc->irq_base + IRQ_MASK);
+	writel_relaxed(~0, dc->irq_base + IRQ_FLAG);
+
+	dc->irq = platform_get_irq(pdev, 0);
+	if (dc->irq < 0)
+		return dc->irq;
+
+	ret = devm_request_threaded_irq(dev, dc->irq, NULL,
+					apple_dockchannel_irq_thread, IRQF_ONESHOT,
+					dev_name(dev), dc);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to request IRQ\n");
+
+	disable_irq(dc->irq);
+
+	dc->chan.con_priv = dc;
+	dc->controller.dev = dev;
+	dc->controller.ops = &apple_dockchannel_mbox_ops;
+	dc->controller.chans = &dc->chan;
+	dc->controller.num_chans = 1;
+	dc->controller.txdone_irq = true;
+	dc->controller.of_xlate = apple_dockchannel_of_xlate;
+
+	ret = devm_mbox_controller_register(dev, &dc->controller);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register mailbox\n");
+
+	return 0;
+}
+
+static const struct of_device_id apple_dockchannel_of_match[] = {
+	{ .compatible = "apple,t8122-dockchannel" },
+	{ .compatible = "apple,t8112-dockchannel" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, apple_dockchannel_of_match);
+
+static struct platform_driver apple_dockchannel_driver = {
+	.driver = {
+		.name = "apple-dockchannel",
+		.of_match_table = apple_dockchannel_of_match,
+	},
+	.probe = apple_dockchannel_probe,
+};
+module_platform_driver(apple_dockchannel_driver);
+
+MODULE_DESCRIPTION("Apple DockChannel mailbox controller");
+MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
+MODULE_AUTHOR("Michael Reeves <michael.reeves077@gmail.com>");
+MODULE_LICENSE("Dual MIT/GPL");
diff --git a/include/linux/mailbox/apple-dockchannel.h b/include/linux/mailbox/apple-dockchannel.h
new file mode 100644
index 000000000..04d2fc44f
--- /dev/null
+++ b/include/linux/mailbox/apple-dockchannel.h
@@ -0,0 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+/*
+ * Apple DockChannel mailbox message format.
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#ifndef _LINUX_MAILBOX_APPLE_DOCKCHANNEL_H_
+#define _LINUX_MAILBOX_APPLE_DOCKCHANNEL_H_
+
+#include <linux/types.h>
+
+/**
+ * struct apple_dockchannel_msg - DockChannel mailbox payload
+ * @data: Pointer to the byte stream payload
+ * @len: Number of payload bytes
+ *
+ * For TX, @data must remain valid until mbox_send_message() completes or the
+ * client receives tx_done in non-blocking mode.
+ *
+ * For RX, @data is owned by the controller and is valid only for the duration
+ * of the rx_callback.
+ */
+struct apple_dockchannel_msg {
+	void *data;
+	size_t len;
+};
+
+#endif /* _LINUX_MAILBOX_APPLE_DOCKCHANNEL_H_ */

-- 
2.55.0

[PATCH v2 06/10] soc: apple: rtkit: Add tracekit endpoint

[Michael Reeves via B4 Relay]

From: Sasha Finkelstein <fnkl.kernel@gmail.com>

The TraceKit endpoint is a system endpoint used by MTP, AOP, and
potentially other Apple RTKit coprocessors.

Start it automatically when it appears in the endpoint map, like the
other known system endpoints, to avoid warnings about an unknown
endpoint.

Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
---
 drivers/soc/apple/rtkit.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/soc/apple/rtkit.c b/drivers/soc/apple/rtkit.c
index a3fdac8f6..1059b4bd8 100644
--- a/drivers/soc/apple/rtkit.c
+++ b/drivers/soc/apple/rtkit.c
@@ -22,6 +22,7 @@ enum {
 	APPLE_RTKIT_EP_DEBUG = 3,
 	APPLE_RTKIT_EP_IOREPORT = 4,
 	APPLE_RTKIT_EP_OSLOG = 8,
+	APPLE_RTKIT_EP_TRACEKIT = 0xa,
 };
 
 #define APPLE_RTKIT_MGMT_TYPE GENMASK_ULL(59, 52)
@@ -191,6 +192,7 @@ static void apple_rtkit_management_rx_epmap(struct apple_rtkit *rtk, u64 msg)
 		case APPLE_RTKIT_EP_DEBUG:
 		case APPLE_RTKIT_EP_IOREPORT:
 		case APPLE_RTKIT_EP_OSLOG:
+		case APPLE_RTKIT_EP_TRACEKIT:
 			dev_dbg(rtk->dev,
 				"RTKit: Starting system endpoint 0x%02x\n", ep);
 			apple_rtkit_start_ep(rtk, ep);

-- 
2.55.0

[PATCH v2 07/10] HID: apple: Add support for DockChannel HID keyboards

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

DockChannel keyboards are registered as host-bus Apple HID devices
instead of USB or Bluetooth devices.

Match them in hid-apple and use the modern Magic Keyboard function-key
table.

Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
---
 drivers/hid/hid-apple.c | 117 +++++++++++++++++++++++++++++-------------------
 include/linux/hid.h     |   1 +
 2 files changed, 72 insertions(+), 46 deletions(-)

diff --git a/drivers/hid/hid-apple.c b/drivers/hid/hid-apple.c
index f6134c582..cebe2f901 100644
--- a/drivers/hid/hid-apple.c
+++ b/drivers/hid/hid-apple.c
@@ -395,6 +395,12 @@ static bool apple_is_omoton_kb066(struct hid_device *hdev)
 		strcmp(hdev->name, "Bluetooth Keyboard") == 0;
 }
 
+static bool apple_is_dockchannel_keyboard(struct hid_device *hdev)
+{
+	return hdev->bus == BUS_HOST &&
+	       hdev->group == HID_GROUP_APPLE_DOCKCHANNEL;
+}
+
 static inline void apple_setup_key_translation(struct input_dev *input,
 		const struct apple_key_translation *table)
 {
@@ -482,53 +488,57 @@ static int hidinput_apple_event(struct hid_device *hid, struct input_dev *input,
 		asc->fn_on = !!value;
 
 	if (real_fnmode) {
-		switch (hid->product) {
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_ANSI:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_ISO:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_JIS:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2009_ANSI:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2009_ISO:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2009_JIS:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2011_ANSI:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2011_ISO:
-		case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2011_JIS:
-			table = magic_keyboard_alu_fn_keys;
-			break;
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2015:
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_NUMPAD_2015:
-			table = magic_keyboard_2015_fn_keys;
-			break;
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2021:
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_FINGERPRINT_2021:
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_NUMPAD_2021:
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2024:
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_FINGERPRINT_2024:
-		case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_NUMPAD_2024:
+		if (apple_is_dockchannel_keyboard(hid)) {
 			table = magic_keyboard_2021_and_2024_fn_keys;
-			break;
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J132:
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J213:
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J680:
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J680_ALT:
-			table = macbookpro_no_esc_fn_keys;
-			break;
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J152F:
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J214K:
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J223:
-			table = macbookpro_dedicated_esc_fn_keys;
-			break;
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J140K:
-		case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J230K:
-			table = apple_fn_keys;
-			break;
-		default:
-			if (hid->product >= USB_DEVICE_ID_APPLE_WELLSPRING4_ANSI &&
-			    hid->product <= USB_DEVICE_ID_APPLE_WELLSPRING4A_JIS)
-				table = macbookair_fn_keys;
-			else if (hid->product < 0x21d || hid->product >= 0x300)
-				table = powerbook_fn_keys;
-			else
+		} else {
+			switch (hid->product) {
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_ANSI:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_ISO:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_JIS:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2009_ANSI:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2009_ISO:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2009_JIS:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2011_ANSI:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2011_ISO:
+			case USB_DEVICE_ID_APPLE_ALU_WIRELESS_2011_JIS:
+				table = magic_keyboard_alu_fn_keys;
+				break;
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2015:
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_NUMPAD_2015:
+				table = magic_keyboard_2015_fn_keys;
+				break;
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2021:
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_FINGERPRINT_2021:
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_NUMPAD_2021:
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_2024:
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_FINGERPRINT_2024:
+			case USB_DEVICE_ID_APPLE_MAGIC_KEYBOARD_NUMPAD_2024:
+				table = magic_keyboard_2021_and_2024_fn_keys;
+				break;
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J132:
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J213:
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J680:
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J680_ALT:
+				table = macbookpro_no_esc_fn_keys;
+				break;
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J152F:
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J214K:
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J223:
+				table = macbookpro_dedicated_esc_fn_keys;
+				break;
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J140K:
+			case USB_DEVICE_ID_APPLE_WELLSPRINGT2_J230K:
 				table = apple_fn_keys;
+				break;
+			default:
+				if (hid->product >= USB_DEVICE_ID_APPLE_WELLSPRING4_ANSI &&
+				    hid->product <= USB_DEVICE_ID_APPLE_WELLSPRING4A_JIS)
+					table = macbookair_fn_keys;
+				else if (hid->product < 0x21d || hid->product >= 0x300)
+					table = powerbook_fn_keys;
+				else
+					table = apple_fn_keys;
+			}
 		}
 
 		trans = apple_find_translation(table, code);
@@ -768,7 +778,7 @@ static int apple_input_configured(struct hid_device *hdev,
 	struct apple_sc *asc = hid_get_drvdata(hdev);
 
 	if (((asc->quirks & APPLE_HAS_FN) && !asc->fn_found) || apple_is_omoton_kb066(hdev)) {
-		hid_info(hdev, "Fn key not found (Apple Wireless Keyboard clone?), disabling Fn key handling\n");
+		hid_info(hdev, "Disabling function quirk for device without function key\n");
 		asc->quirks &= ~APPLE_HAS_FN;
 	}
 
@@ -1019,6 +1029,17 @@ static void apple_remove(struct hid_device *hdev)
 	hid_hw_stop(hdev);
 }
 
+static bool apple_match(struct hid_device *hdev, bool ignore_special_driver)
+{
+	if (ignore_special_driver)
+		return false;
+
+	if (hdev->group == HID_GROUP_APPLE_DOCKCHANNEL)
+		return apple_is_dockchannel_keyboard(hdev);
+
+	return true;
+}
+
 static const struct hid_device_id apple_devices[] = {
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_MIGHTYMOUSE),
 		.driver_data = APPLE_MIGHTYMOUSE | APPLE_INVERT_HWHEEL },
@@ -1240,6 +1261,9 @@ static const struct hid_device_id apple_devices[] = {
 		.driver_data = APPLE_HAS_FN | APPLE_ISO_TILDE_QUIRK },
 	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_TOUCHBAR_BACKLIGHT),
 		.driver_data = APPLE_MAGIC_BACKLIGHT },
+	{ HID_DEVICE(BUS_HOST, HID_GROUP_APPLE_DOCKCHANNEL,
+		     HID_ANY_ID, HID_ANY_ID),
+		.driver_data = APPLE_HAS_FN | APPLE_ISO_TILDE_QUIRK },
 
 	{ }
 };
@@ -1248,6 +1272,7 @@ MODULE_DEVICE_TABLE(hid, apple_devices);
 static struct hid_driver apple_driver = {
 	.name = "apple",
 	.id_table = apple_devices,
+	.match = apple_match,
 	.report_fixup = apple_report_fixup,
 	.probe = apple_probe,
 	.remove = apple_remove,
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 8d17b7416..40be5eabf 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -441,6 +441,7 @@ struct hid_item {
 #define HID_GROUP_STEAM				0x0103
 #define HID_GROUP_LOGITECH_27MHZ_DEVICE		0x0104
 #define HID_GROUP_VIVALDI			0x0105
+#define HID_GROUP_APPLE_DOCKCHANNEL		0x0106
 
 /*
  * HID protocol status

-- 
2.55.0

[PATCH v2 08/10] HID: apple: Add DockChannel HID transport driver

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

Apple MTP exposes internal keyboard and trackpad interfaces over a HID
transport carried by DockChannel.

Add a transport driver that boots the MTP RTKit coprocessor, exchanges
HID packets through the DockChannel mailbox, and registers child HID
interfaces from devicetree.

Use the presence of an STM child node to decide whether to wait for
shared device identifiers. Machines without STM can register their
keyboard without waiting for an interface that never appears. Only
interfaces described by available child nodes are instantiated.

Stop queueing reports during removal, drain packet and device-creation
work, and destroy HID devices before releasing the mailbox. Keep command
acknowledgements flowing until outstanding users have finished.

Co-developed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
---
 MAINTAINERS                         |    1 +
 drivers/hid/Kconfig                 |    2 +
 drivers/hid/Makefile                |    2 +
 drivers/hid/dockchannel/Kconfig     |   14 +
 drivers/hid/dockchannel/Makefile    |    3 +
 drivers/hid/dockchannel/apple-hid.c | 1157 +++++++++++++++++++++++++++++++++++
 6 files changed, 1179 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index e5be5934c..fc20a2781 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2669,6 +2669,7 @@ F:	drivers/clk/clk-apple-nco.c
 F:	drivers/cpufreq/apple-soc-cpufreq.c
 F:	drivers/dma/apple-admac.c
 F:	drivers/gpio/gpio-macsmc.c
+F:	drivers/hid/dockchannel/
 F:	drivers/hwmon/macsmc-hwmon.c
 F:	drivers/pmdomain/apple/
 F:	drivers/i2c/busses/i2c-pasemi-core.c
diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index a81bf51cb..fb8def311 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -1534,6 +1534,8 @@ source "drivers/hid/surface-hid/Kconfig"
 
 source "drivers/hid/intel-thc-hid/Kconfig"
 
+source "drivers/hid/dockchannel/Kconfig"
+
 endif # HID
 
 # USB support may be used with HID disabled
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 48a863b24..e889bd37b 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -184,3 +184,5 @@ obj-$(CONFIG_AMD_SFH_HID)       += amd-sfh-hid/
 obj-$(CONFIG_SURFACE_HID_CORE)  += surface-hid/
 
 obj-$(CONFIG_INTEL_THC_HID)     += intel-thc-hid/
+
+obj-$(CONFIG_APPLE_DOCKCHANNEL_HID)	+= dockchannel/
diff --git a/drivers/hid/dockchannel/Kconfig b/drivers/hid/dockchannel/Kconfig
new file mode 100644
index 000000000..aeb4e4edf
--- /dev/null
+++ b/drivers/hid/dockchannel/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only OR MIT
+
+config APPLE_DOCKCHANNEL_HID
+	tristate "HID over Apple DockChannel"
+	depends on APPLE_DOCKCHANNEL
+	depends on APPLE_RTKIT
+	depends on INPUT
+	depends on OF
+	help
+	  This provides a HID transport layer over the Apple DockChannel
+	  mailbox interface. It is required to support the internal keyboard
+	  and trackpad on M2 and later MacBook models.
+
+	  Say Y here if you have an M2 or later Apple MacBook.
diff --git a/drivers/hid/dockchannel/Makefile b/drivers/hid/dockchannel/Makefile
new file mode 100644
index 000000000..d1a82aa57
--- /dev/null
+++ b/drivers/hid/dockchannel/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only OR MIT
+
+obj-$(CONFIG_APPLE_DOCKCHANNEL_HID)	+= apple-hid.o
diff --git a/drivers/hid/dockchannel/apple-hid.c b/drivers/hid/dockchannel/apple-hid.c
new file mode 100644
index 000000000..1bd4532dd
--- /dev/null
+++ b/drivers/hid/dockchannel/apple-hid.c
@@ -0,0 +1,1157 @@
+// SPDX-License-Identifier: GPL-2.0-only OR MIT
+/*
+ * Apple DockChannel HID transport driver
+ *
+ * Copyright The Asahi Linux Contributors
+ */
+
+#include <linux/bitfield.h>
+#include <linux/completion.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/hid.h>
+#include <linux/io.h>
+#include <linux/mailbox/apple-dockchannel.h>
+#include <linux/mailbox_client.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/soc/apple/rtkit.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/unaligned.h>
+#include <linux/workqueue.h>
+
+#define APPLE_ASC_CPU_CONTROL		0x44
+#define APPLE_ASC_CPU_CONTROL_RUN	BIT(4)
+
+#define COMMAND_TIMEOUT_MS	1000
+#define START_TIMEOUT_MS	2000
+
+#define MAX_INTERFACES		16
+
+#define DCHID_MAX_PAYLOAD	0xffff
+#define DCHID_CHECKSUM_LEN	4
+#define DCHID_RX_BUF_SIZE	(sizeof(struct dchid_hdr) + DCHID_MAX_PAYLOAD + \
+				 DCHID_CHECKSUM_LEN)
+
+#define DCHID_CHANNEL_CMD	0x11
+#define DCHID_CHANNEL_REPORT	0x12
+#define DCHID_CHECKSUM_SEED	0xffffffff
+
+struct dchid_hdr {
+	u8 hdr_len;
+	u8 channel;
+	__le16 length;
+	u8 seq;
+	u8 iface;
+	__le16 pad;
+} __packed;
+
+#define IFACE_COMM	0
+
+#define FLAGS_GROUP	GENMASK(7, 6)
+#define FLAGS_REQ	GENMASK(5, 0)
+
+#define REQ_SET_REPORT	0
+#define REQ_GET_REPORT	1
+
+struct dchid_subhdr {
+	u8 flags;
+	u8 unk;
+	__le16 length;
+	__le32 retcode;
+} __packed;
+
+#define EVENT_INIT	0xf0
+#define EVENT_READY	0xf1
+
+struct dchid_init_hdr {
+	u8 type;
+	u8 unk1;
+	u8 unk2;
+	u8 iface;
+	char name[16];
+	u8 more_packets;
+	u8 unkpad;
+} __packed;
+
+#define INIT_HID_DESCRIPTOR	0
+#define INIT_TERMINATOR		2
+#define INIT_PRODUCT_NAME	7
+
+#define CMD_RESET_INTERFACE	0x40
+#define CMD_RESET_INTERFACE_SUB	1
+#define CMD_ENABLE_INTERFACE	0xb4
+
+struct dchid_init_block_hdr {
+	__le16 type;
+	__le16 length;
+} __packed;
+
+#define STM_REPORT_ID		0x10
+#define STM_REPORT_SERIAL	0x11
+
+struct dchid_stm_id {
+	u8 unk;
+	__le16 vendor_id;
+	__le16 product_id;
+	__le16 version_number;
+	u8 unk2;
+	u8 unk3;
+	u8 keyboard_type;
+	u8 serial_length;
+	/* Serial follows, but we grab it with a different report. */
+} __packed;
+
+struct dchid_work {
+	struct work_struct work;
+	struct dchid_iface *iface;
+
+	struct dchid_hdr hdr;
+	u8 data[];
+};
+
+struct dchid_iface {
+	struct dchid_dev *dchid;
+	struct hid_device *hid;
+	struct workqueue_struct *wq;
+
+	bool creating;
+	struct work_struct create_work;
+
+	int index;
+	const char *name;
+	struct fwnode_handle *fwnode;
+
+	u8 tx_seq;
+	bool deferred;
+	bool starting;
+	bool open;
+	struct completion ready;
+
+	void *hid_desc;
+	size_t hid_desc_len;
+
+	/* Lock for command submission state below */
+	spinlock_t out_lock;
+	u32 out_flags;
+	int out_report;
+	u32 retcode;
+	void *resp_buf;
+	size_t resp_size;
+	struct completion out_complete;
+};
+
+struct dchid_dev {
+	struct device *dev;
+	struct mbox_client dc_mbox_client;
+	struct mbox_chan *dc_mbox;
+
+	struct apple_rtkit *rtk;
+	void __iomem *asc_base;
+	void __iomem *sram_base;
+	struct resource sram_res;
+
+	bool id_ready;
+	struct dchid_stm_id device_id;
+	char serial[64];
+
+	u8 *rx_buf;
+	size_t rx_len;
+	spinlock_t rx_lock; /* serializes report queueing with teardown */
+	bool stopping;
+
+	struct dchid_iface *comm;
+	struct mutex ifaces_lock; /* protects ifaces array */
+	struct dchid_iface *ifaces[MAX_INTERFACES];
+
+	/* Workqueue to asynchronously create HID devices */
+	struct workqueue_struct *new_iface_wq;
+};
+
+static void dchid_destroy_wq(void *data)
+{
+	struct workqueue_struct *wq = data;
+
+	destroy_workqueue(wq);
+}
+
+static void dchid_fwnode_release(void *data)
+{
+	fwnode_handle_put(data);
+}
+
+static void dchid_free_mbox(void *data)
+{
+	mbox_free_channel(data);
+}
+
+static u32 dchid_checksum(const void *data, size_t len)
+{
+	const u8 *p = data;
+	u32 sum = 0;
+	int i;
+
+	while (len >= sizeof(u32)) {
+		sum += get_unaligned_le32(p);
+		p += sizeof(u32);
+		len -= sizeof(u32);
+	}
+
+	if (len) {
+		u32 tmp = 0;
+
+		for (i = 0; i < len; i++)
+			tmp |= p[i] << (i * 8);
+		sum += tmp;
+	}
+
+	return sum;
+}
+
+static void dchid_create_interface_work(struct work_struct *ws);
+
+static struct dchid_iface *
+dchid_get_interface(struct dchid_dev *dchid, int index, const char *name)
+{
+	struct dchid_iface *iface;
+	struct fwnode_handle *fwnode = NULL;
+	int ret;
+
+	if (index >= MAX_INTERFACES) {
+		dev_err(dchid->dev, "interface index %d out of range\n", index);
+		return NULL;
+	}
+
+	mutex_lock(&dchid->ifaces_lock);
+	if (dchid->ifaces[index]) {
+		iface = dchid->ifaces[index];
+		mutex_unlock(&dchid->ifaces_lock);
+		return iface;
+	}
+
+	if (strcmp(name, "comm")) {
+		fwnode = device_get_named_child_node(dchid->dev, name);
+		if (!fwnode || !fwnode_device_is_available(fwnode))
+			goto err_put_fwnode;
+	}
+
+	iface = devm_kzalloc(dchid->dev, sizeof(*iface), GFP_KERNEL);
+	if (!iface)
+		goto err_put_fwnode;
+
+	iface->index = index;
+	iface->name = devm_kstrdup(dchid->dev, name, GFP_KERNEL);
+	if (!iface->name)
+		goto err_put_fwnode;
+
+	iface->dchid = dchid;
+	iface->out_report = -1;
+	init_completion(&iface->out_complete);
+	init_completion(&iface->ready);
+	INIT_WORK(&iface->create_work, dchid_create_interface_work);
+	spin_lock_init(&iface->out_lock);
+
+	iface->wq = alloc_ordered_workqueue("dchid-%s", 0, iface->name);
+	if (!iface->wq)
+		goto err_put_fwnode;
+
+	ret = devm_add_action_or_reset(dchid->dev, dchid_destroy_wq, iface->wq);
+	if (ret)
+		goto err_put_fwnode;
+
+	if (!strcmp(name, "comm")) {
+		/* Comm is not a HID subdevice */
+		dchid->ifaces[index] = iface;
+		mutex_unlock(&dchid->ifaces_lock);
+		return iface;
+	}
+
+	iface->fwnode = fwnode;
+	ret = devm_add_action_or_reset(dchid->dev, dchid_fwnode_release,
+				       iface->fwnode);
+	if (ret)
+		goto err_unlock;
+
+	dchid->ifaces[index] = iface;
+	mutex_unlock(&dchid->ifaces_lock);
+	return iface;
+
+err_put_fwnode:
+	fwnode_handle_put(fwnode);
+err_unlock:
+	mutex_unlock(&dchid->ifaces_lock);
+	return NULL;
+}
+
+static int dchid_send(struct dchid_iface *iface, u32 flags, const void *msg,
+		      size_t size)
+{
+	struct dchid_dev *dchid = iface->dchid;
+	size_t payload_padded = round_up(size, sizeof(u32));
+	size_t total_len = sizeof(struct dchid_hdr) + sizeof(struct dchid_subhdr) +
+			   payload_padded + DCHID_CHECKSUM_LEN;
+	struct apple_dockchannel_msg dc_msg;
+	struct dchid_hdr *hdr;
+	struct dchid_subhdr *sub;
+	u32 *checksum_ptr;
+	u8 *buf;
+	int ret;
+
+	if (total_len > DCHID_RX_BUF_SIZE)
+		return -EINVAL;
+
+	buf = kzalloc(total_len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	hdr = (struct dchid_hdr *)buf;
+	sub = (struct dchid_subhdr *)(buf + sizeof(*hdr));
+	checksum_ptr = (u32 *)(buf + total_len - DCHID_CHECKSUM_LEN);
+
+	hdr->hdr_len = sizeof(*hdr);
+	hdr->channel = DCHID_CHANNEL_CMD;
+	hdr->length = cpu_to_le16(payload_padded + sizeof(*sub));
+	hdr->seq = iface->tx_seq;
+	hdr->iface = iface->index;
+
+	sub->flags = (u8)flags;
+	sub->length = cpu_to_le16(size);
+
+	memcpy(buf + sizeof(*hdr) + sizeof(*sub), msg, size);
+
+	*checksum_ptr = 0xffffffff - dchid_checksum(buf, total_len - DCHID_CHECKSUM_LEN);
+
+	dc_msg.data = buf;
+	dc_msg.len = total_len;
+	ret = mbox_send_message(dchid->dc_mbox, &dc_msg);
+	kfree(buf);
+
+	return ret < 0 ? ret : 0;
+}
+
+static int dchid_cmd(struct dchid_iface *iface, u32 type, u32 req,
+		     void *data, size_t size, void *resp_buf, size_t resp_size)
+{
+	unsigned long flags;
+	int ret;
+	int report_id;
+	bool timed_out = false;
+	u32 out_flags;
+
+	if (size < 1)
+		return -EINVAL;
+
+	report_id = *(u8 *)data;
+	out_flags = FIELD_PREP(FLAGS_GROUP, type) | FIELD_PREP(FLAGS_REQ, req);
+
+	spin_lock_irqsave(&iface->out_lock, flags);
+
+	/* Only one command can be in flight per interface */
+	if (WARN_ON(iface->out_report != -1)) {
+		spin_unlock_irqrestore(&iface->out_lock, flags);
+		return -EBUSY;
+	}
+
+	iface->out_report = report_id;
+	iface->out_flags = out_flags;
+	iface->retcode = 0;
+	iface->resp_buf = resp_buf;
+	iface->resp_size = resp_size;
+	reinit_completion(&iface->out_complete);
+
+	spin_unlock_irqrestore(&iface->out_lock, flags);
+
+	ret = dchid_send(iface, out_flags, data, size);
+	if (ret < 0) {
+		spin_lock_irqsave(&iface->out_lock, flags);
+		iface->out_report = -1;
+		iface->resp_buf = NULL;
+		iface->resp_size = 0;
+		spin_unlock_irqrestore(&iface->out_lock, flags);
+		return ret;
+	}
+
+	if (!wait_for_completion_timeout(&iface->out_complete,
+					 msecs_to_jiffies(COMMAND_TIMEOUT_MS))) {
+		dev_err(iface->dchid->dev, "command 0x%x to iface %d (%s) timed out\n",
+			report_id, iface->index, iface->name);
+		timed_out = true;
+	}
+
+	spin_lock_irqsave(&iface->out_lock, flags);
+
+	if (timed_out && iface->out_report == report_id) {
+		ret = -ETIMEDOUT;
+	} else if (iface->retcode) {
+		dev_err(iface->dchid->dev,
+			"command 0x%x to iface %d (%s) failed with err 0x%x\n",
+			report_id, iface->index, iface->name, iface->retcode);
+		ret = -EIO;
+	} else {
+		ret = iface->resp_size;
+	}
+
+	iface->tx_seq++;
+	iface->out_report = -1;
+	iface->resp_buf = NULL;
+	iface->resp_size = 0;
+	spin_unlock_irqrestore(&iface->out_lock, flags);
+
+	return ret;
+}
+
+static int dchid_comm_cmd(struct dchid_dev *dchid, void *cmd, size_t size)
+{
+	return dchid_cmd(dchid->comm, HID_FEATURE_REPORT, REQ_SET_REPORT,
+			 cmd, size, NULL, 0);
+}
+
+static int dchid_enable_interface(struct dchid_iface *iface)
+{
+	u8 cmd[] = { CMD_ENABLE_INTERFACE, iface->index };
+
+	return dchid_comm_cmd(iface->dchid, cmd, sizeof(cmd));
+}
+
+static int dchid_reset_interface(struct dchid_iface *iface, int state)
+{
+	u8 cmd[] = { CMD_RESET_INTERFACE, CMD_RESET_INTERFACE_SUB, iface->index,
+		     (u8)state };
+
+	return dchid_comm_cmd(iface->dchid, cmd, sizeof(cmd));
+}
+
+static int dchid_start_interface(struct dchid_iface *iface)
+{
+	if (iface->starting)
+		return -EINPROGRESS;
+
+	dev_dbg(iface->dchid->dev, "starting interface %s\n", iface->name);
+
+	iface->starting = true;
+	dchid_reset_interface(iface, 0);
+	dchid_reset_interface(iface, 2);
+
+	return 0;
+}
+
+static int dchid_start(struct hid_device *hdev)
+{
+	return 0;
+}
+
+static void dchid_stop(struct hid_device *hdev)
+{
+}
+
+static int dchid_open(struct hid_device *hdev)
+{
+	struct dchid_iface *iface = hdev->driver_data;
+	int ret;
+
+	if (!completion_done(&iface->ready)) {
+		ret = dchid_start_interface(iface);
+		if (ret < 0)
+			return ret;
+
+		if (!wait_for_completion_timeout(&iface->ready,
+						 msecs_to_jiffies(START_TIMEOUT_MS))) {
+			dev_err(iface->dchid->dev, "iface %s start timed out\n",
+				iface->name);
+			return -ETIMEDOUT;
+		}
+	}
+
+	iface->open = true;
+	return 0;
+}
+
+static void dchid_close(struct hid_device *hdev)
+{
+	struct dchid_iface *iface = hdev->driver_data;
+
+	iface->open = false;
+}
+
+static int dchid_parse(struct hid_device *hdev)
+{
+	struct dchid_iface *iface = hdev->driver_data;
+
+	return hid_parse_report(hdev, iface->hid_desc, iface->hid_desc_len);
+}
+
+/* Note: buf excludes report number. */
+static int dchid_get_report_cmd(struct dchid_iface *iface, u8 reportnum,
+				void *buf, size_t len)
+{
+	int ret;
+
+	ret = dchid_cmd(iface, HID_FEATURE_REPORT, REQ_GET_REPORT, &reportnum, 1,
+			buf, len);
+
+	return ret <= 0 ? ret : ret - 1;
+}
+
+/* Note: buf includes report number. */
+static int dchid_set_report(struct dchid_iface *iface, void *buf, size_t len)
+{
+	return dchid_cmd(iface, HID_OUTPUT_REPORT, REQ_SET_REPORT, buf, len,
+			 NULL, 0);
+}
+
+static int dchid_raw_request(struct hid_device *hdev, unsigned char reportnum,
+			     __u8 *buf, size_t len, unsigned char rtype,
+			     int reqtype)
+{
+	struct dchid_iface *iface = hdev->driver_data;
+
+	switch (reqtype) {
+	case HID_REQ_GET_REPORT:
+		if (len < 1)
+			return -EINVAL;
+
+		buf[0] = reportnum;
+		return dchid_cmd(iface, rtype, REQ_GET_REPORT, &reportnum, 1,
+				 buf + 1, len - 1);
+	case HID_REQ_SET_REPORT:
+		return dchid_set_report(iface, buf, len);
+	default:
+		return -EIO;
+	}
+}
+
+static const struct hid_ll_driver dchid_ll = {
+	.start = dchid_start,
+	.stop = dchid_stop,
+	.open = dchid_open,
+	.close = dchid_close,
+	.parse = dchid_parse,
+	.raw_request = dchid_raw_request,
+};
+
+static void dchid_create_interface_work(struct work_struct *ws)
+{
+	struct dchid_iface *iface = container_of(ws, struct dchid_iface, create_work);
+	struct dchid_dev *dchid = iface->dchid;
+	struct hid_device *hid;
+	char cap_name[16];
+	int ret;
+
+	if (READ_ONCE(dchid->stopping))
+		goto done;
+
+	if (iface->hid) {
+		dev_warn(dchid->dev, "interface %s already created\n", iface->name);
+		goto done;
+	}
+
+	ret = dchid_enable_interface(iface);
+	if (ret < 0) {
+		dev_warn(dchid->dev, "failed to enable %s: %d\n", iface->name, ret);
+		goto done;
+	}
+
+	iface->deferred = false;
+
+	hid = hid_allocate_device();
+	if (IS_ERR(hid))
+		goto done;
+
+	strscpy(cap_name, iface->name, sizeof(cap_name));
+	if (cap_name[0])
+		cap_name[0] = toupper(cap_name[0]);
+	snprintf(hid->name, sizeof(hid->name), "Apple DockChannel %s", cap_name);
+
+	snprintf(hid->phys, sizeof(hid->phys), "%s.%d", dev_name(dchid->dev),
+		 iface->index);
+	strscpy(hid->uniq, dchid->serial, sizeof(hid->uniq));
+
+	hid->ll_driver = &dchid_ll;
+	hid->bus = BUS_HOST;
+	hid->vendor = le16_to_cpu(dchid->device_id.vendor_id);
+	hid->product = le16_to_cpu(dchid->device_id.product_id);
+	hid->version = le16_to_cpu(dchid->device_id.version_number);
+	hid->type = HID_TYPE_OTHER;
+	if (!strcmp(iface->name, "keyboard")) {
+		u32 country_code;
+
+		hid->group = HID_GROUP_APPLE_DOCKCHANNEL;
+
+		/*
+		 * The device provides no reliable way to get the keyboard
+		 * country code, so board devicetrees provide it instead,
+		 * filled by the bootloader.
+		 */
+		if (!fwnode_property_read_u32(iface->fwnode, "hid-country-code",
+					      &country_code))
+			hid->country = country_code;
+	}
+
+	hid->dev.parent = iface->dchid->dev;
+	hid->driver_data = iface;
+	iface->hid = hid;
+
+	ret = hid_add_device(hid);
+	if (ret < 0) {
+		iface->hid = NULL;
+		hid_destroy_device(hid);
+		dev_warn(iface->dchid->dev, "failed to register HID device %s\n",
+			 iface->name);
+	}
+
+done:
+	iface->creating = false;
+}
+
+static int dchid_create_interface(struct dchid_iface *iface)
+{
+	if (iface->creating)
+		return -EBUSY;
+
+	iface->creating = true;
+	return queue_work(iface->dchid->new_iface_wq, &iface->create_work);
+}
+
+static void dchid_handle_descriptor(struct dchid_iface *iface, void *hid_desc,
+				    size_t desc_len)
+{
+	u8 *rdesc;
+	int i;
+
+	if (iface->hid)
+		return;
+
+	rdesc = devm_kmemdup(iface->dchid->dev, hid_desc, desc_len,
+			     GFP_KERNEL);
+	if (!rdesc)
+		return;
+
+	/* Fix up oversized report sizes in DockChannel report descriptors */
+	if (desc_len >= 5) {
+		for (i = 0; i <= (int)desc_len - 5; i++) {
+			if (rdesc[i] == 0x76 && rdesc[i + 1] == 0x00 &&
+			    rdesc[i + 2] == 0x40 && rdesc[i + 3] == 0x95) {
+				u8 count = rdesc[i + 4];
+
+				if (count > 0 && count < 32) {
+					dev_info(iface->dchid->dev,
+						 "fixing up interface %s (%d) report size\n",
+						 iface->name, iface->index);
+					rdesc[i] = 0x75;
+					rdesc[i + 1] = 0x08;
+					rdesc[i + 2] = 0x96;
+					rdesc[i + 3] = 0x00;
+					rdesc[i + 4] = count * 8;
+				}
+			}
+		}
+	}
+
+	iface->hid_desc = rdesc;
+	iface->hid_desc_len = desc_len;
+}
+
+static void dchid_handle_ready(struct dchid_dev *dchid, void *data, size_t length)
+{
+	struct dchid_iface *iface;
+	u8 *pkt = data;
+	u8 index;
+	int i;
+	int ret;
+
+	if (length < 2)
+		return;
+
+	index = pkt[1];
+	if (index >= MAX_INTERFACES)
+		return;
+
+	iface = dchid->ifaces[index];
+	if (!iface)
+		return;
+
+	dev_dbg(dchid->dev, "interface %s is now ready\n", iface->name);
+	complete_all(&iface->ready);
+
+	/* When STM is ready, grab global device info */
+	if (!strcmp(iface->name, "stm")) {
+		ret = dchid_get_report_cmd(iface, STM_REPORT_ID, &dchid->device_id,
+					   sizeof(dchid->device_id));
+		if (ret < (int)sizeof(dchid->device_id)) {
+			dev_warn(iface->dchid->dev, "failed to get device ID from STM\n");
+			/* Fake it and keep going. Things might still work. */
+			memset(&dchid->device_id, 0, sizeof(dchid->device_id));
+		}
+
+		ret = dchid_get_report_cmd(iface, STM_REPORT_SERIAL, dchid->serial,
+					   sizeof(dchid->serial) - 1);
+		if (ret < 0) {
+			dev_warn(iface->dchid->dev, "failed to get serial from STM\n");
+			dchid->serial[0] = 0;
+		}
+
+		dchid->id_ready = true;
+		for (i = 0; i < MAX_INTERFACES; i++) {
+			if (!dchid->ifaces[i] || !dchid->ifaces[i]->deferred)
+				continue;
+			dchid_create_interface(dchid->ifaces[i]);
+		}
+	}
+}
+
+static void dchid_handle_init(struct dchid_dev *dchid, void *data, size_t length)
+{
+	struct dchid_init_hdr *hdr = data;
+	struct dchid_init_block_hdr *blk;
+	struct dchid_iface *iface;
+	u8 *p = data;
+
+	if (length < sizeof(*hdr))
+		return;
+
+	if (!memchr(hdr->name, 0, sizeof(hdr->name)))
+		return;
+
+	iface = dchid_get_interface(dchid, hdr->iface, hdr->name);
+	if (!iface)
+		return;
+
+	p += sizeof(*hdr);
+	length -= sizeof(*hdr);
+
+	while (length >= sizeof(*blk)) {
+		u16 blk_len;
+
+		blk = (struct dchid_init_block_hdr *)p;
+		p += sizeof(*blk);
+		length -= sizeof(*blk);
+
+		blk_len = le16_to_cpu(blk->length);
+		if (blk_len > length)
+			break;
+
+		switch (le16_to_cpu(blk->type)) {
+		case INIT_HID_DESCRIPTOR:
+			dchid_handle_descriptor(iface, p, blk_len);
+			break;
+		case INIT_PRODUCT_NAME:
+			if (blk_len > 0 && p[blk_len - 1] != 0)
+				dev_warn(dchid->dev, "unterminated product name for %s\n",
+					 iface->name);
+			break;
+		}
+
+		p += blk_len;
+		length -= blk_len;
+
+		if (le16_to_cpu(blk->type) == INIT_TERMINATOR)
+			break;
+	}
+
+	if (hdr->more_packets)
+		return;
+
+	/* Wait for the shared device IDs only on machines with an STM. */
+	if (dchid->id_ready || !strcmp(iface->name, "stm"))
+		dchid_create_interface(iface);
+	else
+		iface->deferred = true;
+}
+
+static void dchid_handle_event(struct dchid_dev *dchid, void *data, size_t length)
+{
+	u8 *p = data;
+
+	if (!length)
+		return;
+
+	switch (*p) {
+	case EVENT_INIT:
+		dchid_handle_init(dchid, data, length);
+		break;
+	case EVENT_READY:
+		dchid_handle_ready(dchid, data, length);
+		break;
+	}
+}
+
+static void dchid_handle_report(struct dchid_iface *iface, void *data, size_t length)
+{
+	if (!iface->hid || !iface->open)
+		return;
+
+	hid_input_report(iface->hid, HID_INPUT_REPORT, data, length, 1);
+}
+
+static void dchid_packet_work(struct work_struct *ws)
+{
+	struct dchid_work *work = container_of(ws, struct dchid_work, work);
+	struct dchid_subhdr *shdr = (void *)work->data;
+	struct dchid_dev *dchid = work->iface->dchid;
+	u16 hdr_len = le16_to_cpu(work->hdr.length);
+	u16 sub_len;
+	int type;
+	u8 *payload;
+
+	if (READ_ONCE(dchid->stopping))
+		goto done;
+
+	if (hdr_len < sizeof(*shdr)) {
+		dev_err(dchid->dev, "bad subheader length\n");
+		goto done;
+	}
+
+	sub_len = le16_to_cpu(shdr->length);
+	if (sub_len > hdr_len - sizeof(*shdr)) {
+		dev_err(dchid->dev, "bad subheader length\n");
+		goto done;
+	}
+
+	type = FIELD_GET(FLAGS_GROUP, shdr->flags);
+	payload = work->data + sizeof(*shdr);
+
+	switch (type) {
+	case HID_INPUT_REPORT:
+		if (work->hdr.iface == IFACE_COMM)
+			dchid_handle_event(dchid, payload, sub_len);
+		else
+			dchid_handle_report(work->iface, payload, sub_len);
+		break;
+	}
+
+done:
+	kfree(work);
+}
+
+static void dchid_handle_ack(struct dchid_iface *iface, struct dchid_hdr *hdr,
+			     void *data)
+{
+	struct dchid_subhdr *shdr = data;
+	u8 *payload = data + sizeof(*shdr);
+	u16 hdr_len = le16_to_cpu(hdr->length);
+	u16 sub_len = le16_to_cpu(shdr->length);
+	unsigned long flags;
+	bool complete_cmd = false;
+
+	if (hdr_len < sizeof(*shdr) || sub_len > hdr_len - sizeof(*shdr) ||
+	    sub_len < 1)
+		return;
+
+	spin_lock_irqsave(&iface->out_lock, flags);
+
+	if (shdr->flags == iface->out_flags && iface->tx_seq == hdr->seq &&
+	    iface->out_report == payload[0]) {
+		if (iface->resp_buf && iface->resp_size)
+			memcpy(iface->resp_buf, payload + 1,
+			       min_t(size_t, sub_len - 1, iface->resp_size));
+
+		iface->resp_size = sub_len;
+		iface->out_report = -1;
+		iface->retcode = le32_to_cpu(shdr->retcode);
+		complete_cmd = true;
+	}
+
+	spin_unlock_irqrestore(&iface->out_lock, flags);
+
+	if (complete_cmd)
+		complete(&iface->out_complete);
+}
+
+static void dchid_process_packet(struct dchid_dev *dchid, struct dchid_hdr *hdr,
+				 u8 *payload, size_t payload_len, u8 *packet,
+				 size_t packet_len)
+{
+	struct dchid_work *work;
+	unsigned long flags;
+
+	if (dchid_checksum(packet, packet_len) != DCHID_CHECKSUM_SEED) {
+		dev_err_ratelimited(dchid->dev, "checksum error\n");
+		return;
+	}
+
+	if (payload_len < sizeof(struct dchid_subhdr))
+		return;
+
+	if (hdr->iface >= MAX_INTERFACES || !dchid->ifaces[hdr->iface])
+		return;
+
+	if (hdr->channel == DCHID_CHANNEL_CMD) {
+		dchid_handle_ack(dchid->ifaces[hdr->iface], hdr, payload);
+		return;
+	}
+
+	if (hdr->channel != DCHID_CHANNEL_REPORT)
+		return;
+
+	work = kzalloc(sizeof(*work) + payload_len, GFP_ATOMIC);
+	if (!work)
+		return;
+
+	work->hdr = *hdr;
+	work->iface = dchid->ifaces[hdr->iface];
+	memcpy(work->data, payload, payload_len);
+	INIT_WORK(&work->work, dchid_packet_work);
+
+	spin_lock_irqsave(&dchid->rx_lock, flags);
+	if (dchid->stopping)
+		kfree(work);
+	else
+		queue_work(work->iface->wq, &work->work);
+	spin_unlock_irqrestore(&dchid->rx_lock, flags);
+}
+
+static void dchid_consume_rx(struct dchid_dev *dchid)
+{
+	while (dchid->rx_len >= sizeof(struct dchid_hdr)) {
+		struct dchid_hdr *hdr = (struct dchid_hdr *)dchid->rx_buf;
+		size_t payload_len;
+		size_t packet_len;
+
+		if (hdr->hdr_len != sizeof(*hdr)) {
+			dev_err_ratelimited(dchid->dev, "bad header length %u\n",
+					    hdr->hdr_len);
+			dchid->rx_len = 0;
+			return;
+		}
+
+		payload_len = le16_to_cpu(hdr->length);
+		packet_len = sizeof(*hdr) + payload_len + DCHID_CHECKSUM_LEN;
+		if (packet_len > DCHID_RX_BUF_SIZE) {
+			dev_err_ratelimited(dchid->dev, "oversized packet %zu\n",
+					    packet_len);
+			dchid->rx_len = 0;
+			return;
+		}
+
+		if (dchid->rx_len < packet_len)
+			return;
+
+		dchid_process_packet(dchid, hdr, dchid->rx_buf + sizeof(*hdr),
+				     payload_len, dchid->rx_buf, packet_len);
+
+		dchid->rx_len -= packet_len;
+		memmove(dchid->rx_buf, dchid->rx_buf + packet_len, dchid->rx_len);
+	}
+}
+
+static void dchid_rx_callback(struct mbox_client *cl, void *mssg)
+{
+	struct dchid_dev *dchid = container_of(cl, struct dchid_dev, dc_mbox_client);
+	struct apple_dockchannel_msg *msg = mssg;
+
+	if (!msg || !msg->data || !msg->len)
+		return;
+
+	if (msg->len > DCHID_RX_BUF_SIZE - dchid->rx_len) {
+		dev_err_ratelimited(dchid->dev, "RX buffer overflow\n");
+		dchid->rx_len = 0;
+		return;
+	}
+
+	memcpy(dchid->rx_buf + dchid->rx_len, msg->data, msg->len);
+	dchid->rx_len += msg->len;
+
+	dchid_consume_rx(dchid);
+}
+
+static int dchid_rtkit_shmem_setup(void *cookie, struct apple_rtkit_shmem *bfr)
+{
+	struct dchid_dev *dchid = cookie;
+	struct resource res = {
+		.start = bfr->iova,
+		.end = bfr->iova + bfr->size - 1,
+		.name = "rtkit_map",
+	};
+
+	if (!bfr->iova) {
+		bfr->buffer = dma_alloc_coherent(dchid->dev, bfr->size,
+						 &bfr->iova, GFP_KERNEL);
+		if (!bfr->buffer)
+			return -ENOMEM;
+		return 0;
+	}
+
+	if (!dchid->sram_res.start)
+		return -EFAULT;
+
+	res.flags = dchid->sram_res.flags;
+	if (res.end < res.start || !resource_contains(&dchid->sram_res, &res))
+		return -EFAULT;
+
+	bfr->iomem = dchid->sram_base + (res.start - dchid->sram_res.start);
+	bfr->is_mapped = true;
+
+	return 0;
+}
+
+static void dchid_rtkit_shmem_destroy(void *cookie, struct apple_rtkit_shmem *bfr)
+{
+	struct dchid_dev *dchid = cookie;
+
+	if (bfr->buffer)
+		dma_free_coherent(dchid->dev, bfr->size, bfr->buffer, bfr->iova);
+}
+
+static const struct apple_rtkit_ops dchid_rtkit_ops = {
+	.shmem_setup = dchid_rtkit_shmem_setup,
+	.shmem_destroy = dchid_rtkit_shmem_destroy,
+};
+
+static int dchid_map_helper_cpu(struct platform_device *pdev, struct dchid_dev *dchid)
+{
+	struct resource *res;
+
+	dchid->asc_base = devm_platform_ioremap_resource_byname(pdev, "coproc-asc");
+	if (IS_ERR(dchid->asc_base))
+		return PTR_ERR(dchid->asc_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "coproc-sram");
+	if (!res)
+		return -EINVAL;
+
+	dchid->sram_res = *res;
+
+	dchid->sram_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dchid->sram_base))
+		return PTR_ERR(dchid->sram_base);
+
+	return 0;
+}
+
+static int dchid_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dchid_dev *dchid;
+	struct fwnode_handle *stm;
+	int ret;
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(44));
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to set DMA mask\n");
+
+	dchid = devm_kzalloc(dev, sizeof(*dchid), GFP_KERNEL);
+	if (!dchid)
+		return -ENOMEM;
+
+	dchid->rx_buf = devm_kmalloc(dev, DCHID_RX_BUF_SIZE, GFP_KERNEL);
+	if (!dchid->rx_buf)
+		return -ENOMEM;
+
+	dchid->dev = dev;
+	stm = device_get_named_child_node(dev, "stm");
+	dchid->id_ready = !stm || !fwnode_device_is_available(stm);
+	fwnode_handle_put(stm);
+	mutex_init(&dchid->ifaces_lock);
+	spin_lock_init(&dchid->rx_lock);
+	platform_set_drvdata(pdev, dchid);
+
+	ret = dchid_map_helper_cpu(pdev, dchid);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to map helper CPU\n");
+
+	dchid->new_iface_wq = alloc_ordered_workqueue("dchid-new", 0);
+	if (!dchid->new_iface_wq)
+		return dev_err_probe(dev, -ENOMEM, "failed to allocate workqueue\n");
+
+	ret = devm_add_action_or_reset(dev, dchid_destroy_wq, dchid->new_iface_wq);
+	if (ret)
+		return ret;
+
+	dchid->comm = dchid_get_interface(dchid, IFACE_COMM, "comm");
+	if (!dchid->comm)
+		return dev_err_probe(dev, -EIO, "failed to init comm interface\n");
+
+	dchid->dc_mbox_client.dev = dev;
+	dchid->dc_mbox_client.tx_block = true;
+	dchid->dc_mbox_client.rx_callback = dchid_rx_callback;
+
+	dchid->dc_mbox = mbox_request_channel_byname(&dchid->dc_mbox_client,
+						     "dockchannel");
+	if (IS_ERR(dchid->dc_mbox))
+		return dev_err_probe(dev, PTR_ERR(dchid->dc_mbox),
+				     "failed to request DockChannel mailbox\n");
+
+	ret = devm_add_action_or_reset(dev, dchid_free_mbox, dchid->dc_mbox);
+	if (ret)
+		return ret;
+
+	dchid->rtk = devm_apple_rtkit_init(dev, dchid, "asc", 0, &dchid_rtkit_ops);
+	if (IS_ERR(dchid->rtk))
+		return dev_err_probe(dev, PTR_ERR(dchid->rtk), "failed to init RTKit\n");
+
+	writel_relaxed(APPLE_ASC_CPU_CONTROL_RUN,
+		       dchid->asc_base + APPLE_ASC_CPU_CONTROL);
+
+	ret = apple_rtkit_wake(dchid->rtk);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to wake coprocessor\n");
+
+	return 0;
+}
+
+static void dchid_remove(struct platform_device *pdev)
+{
+	struct dchid_dev *dchid = platform_get_drvdata(pdev);
+	unsigned long flags;
+	int i;
+
+	/* Stop queueing reports, but keep receiving command acknowledgements. */
+	spin_lock_irqsave(&dchid->rx_lock, flags);
+	WRITE_ONCE(dchid->stopping, true);
+	spin_unlock_irqrestore(&dchid->rx_lock, flags);
+
+	/* Comm work can create interfaces, so drain it before walking ifaces. */
+	flush_workqueue(dchid->comm->wq);
+
+	/* Packet work can queue creation work; drain the queues in that order. */
+	for (i = 0; i < MAX_INTERFACES; i++) {
+		struct dchid_iface *iface = dchid->ifaces[i];
+
+		if (iface)
+			flush_workqueue(iface->wq);
+	}
+	flush_workqueue(dchid->new_iface_wq);
+
+	for (i = 0; i < MAX_INTERFACES; i++) {
+		struct dchid_iface *iface = dchid->ifaces[i];
+
+		if (iface && iface->hid)
+			hid_destroy_device(iface->hid);
+	}
+
+	if (apple_rtkit_is_running(dchid->rtk))
+		apple_rtkit_quiesce(dchid->rtk);
+
+	devm_release_action(&pdev->dev, dchid_free_mbox, dchid->dc_mbox);
+	dchid->dc_mbox = NULL;
+	writel_relaxed(0, dchid->asc_base + APPLE_ASC_CPU_CONTROL);
+}
+
+static const struct of_device_id dchid_of_match[] = {
+	{ .compatible = "apple,t8122-dockchannel-hid" },
+	{ .compatible = "apple,t8112-dockchannel-hid" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dchid_of_match);
+
+static struct platform_driver dchid_platform_driver = {
+	.driver = {
+		.name = "dockchannel-hid",
+		.of_match_table = dchid_of_match,
+	},
+	.probe = dchid_probe,
+	.remove = dchid_remove,
+};
+module_platform_driver(dchid_platform_driver);
+
+MODULE_DESCRIPTION("Apple DockChannel HID transport driver");
+MODULE_AUTHOR("Hector Martin <marcan@marcan.st>");
+MODULE_AUTHOR("Michael Reeves <michael.reeves077@gmail.com>");
+MODULE_LICENSE("Dual MIT/GPL");

-- 
2.55.0

[PATCH v2 09/10] arm64: dts: apple: Add MTP DockChannel HID nodes

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

Add disabled MTP nodes for the Apple SoCs used by M2 and M3 systems.

Each instance describes the RTKit ASC mailbox, MTP DART, DockChannel
mailbox, and DockChannel HID client. Board files can enable them on
machines that route internal input through MTP.

Co-developed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
---
 arch/arm64/boot/dts/apple/t602x-die0.dtsi | 46 ++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/apple/t6030.dtsi      | 46 ++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/apple/t6031-die0.dtsi | 46 ++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8112.dtsi      | 46 ++++++++++++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8122.dtsi      | 47 +++++++++++++++++++++++++++++++
 5 files changed, 231 insertions(+)

diff --git a/arch/arm64/boot/dts/apple/t602x-die0.dtsi b/arch/arm64/boot/dts/apple/t602x-die0.dtsi
index c33623f0e..5f62d0a9c 100644
--- a/arch/arm64/boot/dts/apple/t602x-die0.dtsi
+++ b/arch/arm64/boot/dts/apple/t602x-die0.dtsi
@@ -161,6 +161,52 @@ pinctrl_smc: pinctrl@2a2820000 {
 				<AIC_IRQ 0 857 IRQ_TYPE_LEVEL_HIGH>;
 	};
 
+	mtp_mbox: mbox@2a9408000 {
+		compatible = "apple,t6020-asc-mailbox", "apple,asc-mailbox-v4";
+		reg = <0x2 0xa9408000 0x0 0x4000>;
+		interrupt-parent = <&aic>;
+		interrupts = <AIC_IRQ 0 693 IRQ_TYPE_LEVEL_HIGH>,
+			     <AIC_IRQ 0 694 IRQ_TYPE_LEVEL_HIGH>,
+			     <AIC_IRQ 0 695 IRQ_TYPE_LEVEL_HIGH>,
+			     <AIC_IRQ 0 696 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "send-empty", "send-not-empty",
+				  "recv-empty", "recv-not-empty";
+		#mbox-cells = <0>;
+		status = "disabled";
+	};
+
+	mtp_dart: iommu@2a9808000 {
+		compatible = "apple,t6020-dart", "apple,t8110-dart";
+		reg = <0x2 0xa9808000 0x0 0x4000>;
+		interrupt-parent = <&aic>;
+		interrupts = <AIC_IRQ 0 676 IRQ_TYPE_LEVEL_HIGH>;
+		#iommu-cells = <1>;
+		status = "disabled";
+	};
+
+	mtp_dockchannel: mailbox@2a9b14000 {
+		compatible = "apple,t6020-dockchannel", "apple,t8112-dockchannel";
+		reg = <0x2 0xa9b14000 0x0 0x4000>,
+		      <0x2 0xa9b30000 0x0 0x4000>,
+		      <0x2 0xa9b34000 0x0 0x4000>;
+		reg-names = "irq", "config", "data";
+		interrupt-parent = <&aic>;
+		interrupts = <AIC_IRQ 0 677 IRQ_TYPE_LEVEL_HIGH>;
+		#mbox-cells = <0>;
+		status = "disabled";
+	};
+
+	mtp_hid: hid@2a9400000 {
+		compatible = "apple,t6020-dockchannel-hid", "apple,t8112-dockchannel-hid";
+		reg = <0x2 0xa9400000 0x0 0x4000>,
+		      <0x2 0xa9c00000 0x0 0x100000>;
+		reg-names = "coproc-asc", "coproc-sram";
+		mboxes = <&mtp_mbox>, <&mtp_dockchannel>;
+		mbox-names = "asc", "dockchannel";
+		iommus = <&mtp_dart 1>;
+		status = "disabled";
+	};
+
 	sio_dart: iommu@39b008000 {
 		compatible = "apple,t6020-dart", "apple,t8110-dart";
 		reg = <0x3 0x9b008000 0x0 0x8000>;
diff --git a/arch/arm64/boot/dts/apple/t6030.dtsi b/arch/arm64/boot/dts/apple/t6030.dtsi
index dda9568af..e460e547e 100644
--- a/arch/arm64/boot/dts/apple/t6030.dtsi
+++ b/arch/arm64/boot/dts/apple/t6030.dtsi
@@ -474,6 +474,52 @@ wdt: watchdog@3642b0000 {
 			interrupts = <AIC_IRQ 480 IRQ_TYPE_LEVEL_HIGH>;
 		};
 
+		mtp_mbox: mbox@37a408000 {
+			compatible = "apple,t6030-asc-mailbox", "apple,asc-mailbox-v4";
+			reg = <0x3 0x7a408000 0x0 0x4000>;
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 953 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 954 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 955 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 956 IRQ_TYPE_LEVEL_HIGH>;
+			interrupt-names = "send-empty", "send-not-empty",
+					  "recv-empty", "recv-not-empty";
+			#mbox-cells = <0>;
+			status = "disabled";
+		};
+
+		mtp_dart: iommu@37a808000 {
+			compatible = "apple,t6030-dart", "apple,t8110-dart";
+			reg = <0x3 0x7a808000 0x0 0x4000>;
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 937 IRQ_TYPE_LEVEL_HIGH>;
+			#iommu-cells = <1>;
+			status = "disabled";
+		};
+
+		mtp_dockchannel: mailbox@37ab14000 {
+			compatible = "apple,t6030-dockchannel", "apple,t8112-dockchannel";
+			reg = <0x3 0x7ab14000 0x0 0x4000>,
+			      <0x3 0x7ab30000 0x0 0x4000>,
+			      <0x3 0x7ab34000 0x0 0x4000>;
+			reg-names = "irq", "config", "data";
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 939 IRQ_TYPE_LEVEL_HIGH>;
+			#mbox-cells = <0>;
+			status = "disabled";
+		};
+
+		mtp_hid: hid@37a400000 {
+			compatible = "apple,t6030-dockchannel-hid", "apple,t8112-dockchannel-hid";
+			reg = <0x3 0x7a400000 0x0 0x4000>,
+			      <0x3 0x7ac00000 0x0 0x100000>;
+			reg-names = "coproc-asc", "coproc-sram";
+			mboxes = <&mtp_mbox>, <&mtp_dockchannel>;
+			mbox-names = "asc", "dockchannel";
+			iommus = <&mtp_dart 1>;
+			status = "disabled";
+		};
+
 		pinctrl_smc: pinctrl@36c820000 {
 			compatible = "apple,t6030-pinctrl", "apple,t8103-pinctrl";
 			reg = <0x3 0x6c820000 0x0 0x4000>;
diff --git a/arch/arm64/boot/dts/apple/t6031-die0.dtsi b/arch/arm64/boot/dts/apple/t6031-die0.dtsi
index 47d08672a..d7a6d72b3 100644
--- a/arch/arm64/boot/dts/apple/t6031-die0.dtsi
+++ b/arch/arm64/boot/dts/apple/t6031-die0.dtsi
@@ -195,3 +195,49 @@ serial0: serial@391200000 {
 		power-domains = <&ps_uart0>;
 		status = "disabled";
 	};
+
+	mtp_mbox: mbox@2ac408000 {
+		compatible = "apple,t6031-asc-mailbox", "apple,asc-mailbox-v4";
+		reg = <0x2 0xac408000 0x0 0x4000>;
+		interrupt-parent = <&aic>;
+		interrupts = <AIC_IRQ 0 692 IRQ_TYPE_LEVEL_HIGH>,
+			     <AIC_IRQ 0 693 IRQ_TYPE_LEVEL_HIGH>,
+			     <AIC_IRQ 0 694 IRQ_TYPE_LEVEL_HIGH>,
+			     <AIC_IRQ 0 695 IRQ_TYPE_LEVEL_HIGH>;
+		interrupt-names = "send-empty", "send-not-empty",
+				  "recv-empty", "recv-not-empty";
+		#mbox-cells = <0>;
+		status = "disabled";
+	};
+
+	mtp_dart: iommu@2ac808000 {
+		compatible = "apple,t6031-dart", "apple,t8110-dart";
+		reg = <0x2 0xac808000 0x0 0x4000>;
+		interrupt-parent = <&aic>;
+		interrupts = <AIC_IRQ 0 675 IRQ_TYPE_LEVEL_HIGH>;
+		#iommu-cells = <1>;
+		status = "disabled";
+	};
+
+	mtp_dockchannel: mailbox@2acb14000 {
+		compatible = "apple,t6031-dockchannel", "apple,t8112-dockchannel";
+		reg = <0x2 0xacb14000 0x0 0x4000>,
+		      <0x2 0xacb30000 0x0 0x4000>,
+		      <0x2 0xacb34000 0x0 0x4000>;
+		reg-names = "irq", "config", "data";
+		interrupt-parent = <&aic>;
+		interrupts = <AIC_IRQ 0 676 IRQ_TYPE_LEVEL_HIGH>;
+		#mbox-cells = <0>;
+		status = "disabled";
+	};
+
+	mtp_hid: hid@2ac400000 {
+		compatible = "apple,t6031-dockchannel-hid", "apple,t8112-dockchannel-hid";
+		reg = <0x2 0xac400000 0x0 0x4000>,
+		      <0x2 0xacc00000 0x0 0x100000>;
+		reg-names = "coproc-asc", "coproc-sram";
+		mboxes = <&mtp_mbox>, <&mtp_dockchannel>;
+		mbox-names = "asc", "dockchannel";
+		iommus = <&mtp_dart 1>;
+		status = "disabled";
+	};
diff --git a/arch/arm64/boot/dts/apple/t8112.dtsi b/arch/arm64/boot/dts/apple/t8112.dtsi
index ec248ca05..d5c2f35ef 100644
--- a/arch/arm64/boot/dts/apple/t8112.dtsi
+++ b/arch/arm64/boot/dts/apple/t8112.dtsi
@@ -987,6 +987,52 @@ pinctrl_aop: pinctrl@24a820000 {
 				     <AIC_IRQ 307 IRQ_TYPE_LEVEL_HIGH>;
 		};
 
+		mtp_mbox: mbox@24e408000 {
+			compatible = "apple,t8112-asc-mailbox", "apple,asc-mailbox-v4";
+			reg = <0x2 0x4e408000 0x0 0x4000>;
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 864 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 865 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 866 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 867 IRQ_TYPE_LEVEL_HIGH>;
+			interrupt-names = "send-empty", "send-not-empty",
+					  "recv-empty", "recv-not-empty";
+			#mbox-cells = <0>;
+			status = "disabled";
+		};
+
+		mtp_dart: iommu@24e808000 {
+			compatible = "apple,t8110-dart";
+			reg = <0x2 0x4e808000 0x0 0x4000>;
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 848 IRQ_TYPE_LEVEL_HIGH>;
+			#iommu-cells = <1>;
+			status = "disabled";
+		};
+
+		mtp_dockchannel: mailbox@24eb14000 {
+			compatible = "apple,t8112-dockchannel";
+			reg = <0x2 0x4eb14000 0x0 0x4000>,
+			      <0x2 0x4eb30000 0x0 0x4000>,
+			      <0x2 0x4eb34000 0x0 0x4000>;
+			reg-names = "irq", "config", "data";
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 850 IRQ_TYPE_LEVEL_HIGH>;
+			#mbox-cells = <0>;
+			status = "disabled";
+		};
+
+		mtp_hid: hid@24e400000 {
+			compatible = "apple,t8112-dockchannel-hid";
+			reg = <0x2 0x4e400000 0x0 0x4000>,
+			      <0x2 0x4ec00000 0x0 0x100000>;
+			reg-names = "coproc-asc", "coproc-sram";
+			mboxes = <&mtp_mbox>, <&mtp_dockchannel>;
+			mbox-names = "asc", "dockchannel";
+			iommus = <&mtp_dart 1>;
+			status = "disabled";
+		};
+
 		ans_mbox: mbox@277408000 {
 			compatible = "apple,t8112-asc-mailbox", "apple,asc-mailbox-v4";
 			reg = <0x2 0x77408000 0x0 0x4000>;
diff --git a/arch/arm64/boot/dts/apple/t8122.dtsi b/arch/arm64/boot/dts/apple/t8122.dtsi
index 1ee61c5b3..47102f431 100644
--- a/arch/arm64/boot/dts/apple/t8122.dtsi
+++ b/arch/arm64/boot/dts/apple/t8122.dtsi
@@ -438,6 +438,53 @@ pinctrl_aop: pinctrl@2f4824000 {
 				     <AIC_IRQ 351 IRQ_TYPE_LEVEL_HIGH>,
 				     <AIC_IRQ 352 IRQ_TYPE_LEVEL_HIGH>;
 		};
+
+		mtp_mbox: mbox@2fa408000 {
+			compatible = "apple,t8122-asc-mailbox", "apple,asc-mailbox-v4";
+			reg = <0x2 0xfa408000 0x0 0x4000>;
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 838 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 839 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 840 IRQ_TYPE_LEVEL_HIGH>,
+				     <AIC_IRQ 841 IRQ_TYPE_LEVEL_HIGH>;
+			interrupt-names = "send-empty", "send-not-empty",
+					  "recv-empty", "recv-not-empty";
+			#mbox-cells = <0>;
+			status = "disabled";
+		};
+
+		mtp_dart: iommu@2fa808000 {
+			compatible = "apple,t8122-dart", "apple,t8110-dart";
+			reg = <0x2 0xfa808000 0x0 0x4000>;
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 822 IRQ_TYPE_LEVEL_HIGH>;
+			#iommu-cells = <1>;
+			status = "disabled";
+		};
+
+		mtp_dockchannel: mailbox@2fab14000 {
+			compatible = "apple,t8122-dockchannel", "apple,t8112-dockchannel";
+			reg = <0x2 0xfab14000 0x0 0x4000>,
+			      <0x2 0xfab30000 0x0 0x4000>,
+			      <0x2 0xfab34000 0x0 0x4000>;
+			reg-names = "irq", "config", "data";
+			interrupt-parent = <&aic>;
+			interrupts = <AIC_IRQ 824 IRQ_TYPE_LEVEL_HIGH>;
+			#mbox-cells = <0>;
+			status = "disabled";
+		};
+
+		mtp_hid: hid@2fa400000 {
+			compatible = "apple,t8122-dockchannel-hid",
+				     "apple,t8112-dockchannel-hid";
+			reg = <0x2 0xfa400000 0x0 0x4000>,
+			      <0x2 0xfac00000 0x0 0x100000>;
+			reg-names = "coproc-asc", "coproc-sram";
+			mboxes = <&mtp_mbox>, <&mtp_dockchannel>;
+			mbox-names = "asc", "dockchannel";
+			iommus = <&mtp_dart 1>;
+			status = "disabled";
+		};
 	};
 };
 

-- 
2.55.0

[PATCH v2 10/10] arm64: dts: apple: Enable DockChannel HID on M2 and M3 laptops

[Michael Reeves via B4 Relay]

From: Michael Reeves <michael.reeves077@gmail.com>

Enable the MTP mailbox, DART, DockChannel mailbox, and HID transport on
the M2 and M3 laptop device trees using this internal input path.

Add a keyboard alias and keyboard child node for each machine so the
transport can expose the internal keyboard.

Co-developed-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Hector Martin <marcan@marcan.st>
Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
---
 arch/arm64/boot/dts/apple/t602x-j414-j416.dtsi | 29 ++++++++++++++++++++++++++
 arch/arm64/boot/dts/apple/t603x-j514-j516.dtsi | 24 +++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8112-j413.dts       | 24 +++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8112-j415.dts       | 24 +++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8112-j493.dts       | 26 ++++++++++++++++++++++-
 arch/arm64/boot/dts/apple/t8122-j504.dts       | 26 +++++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8122-j613.dts       | 27 ++++++++++++++++++++++++
 arch/arm64/boot/dts/apple/t8122-j615.dts       | 27 ++++++++++++++++++++++++
 8 files changed, 206 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/apple/t602x-j414-j416.dtsi b/arch/arm64/boot/dts/apple/t602x-j414-j416.dtsi
index 0e806d8dd..91fda44d9 100644
--- a/arch/arm64/boot/dts/apple/t602x-j414-j416.dtsi
+++ b/arch/arm64/boot/dts/apple/t602x-j414-j416.dtsi
@@ -16,6 +16,12 @@
 
 #include "t600x-j314-j316.dtsi"
 
+/ {
+	aliases {
+		keyboard = &keyboard;
+	};
+};
+
 &framebuffer0 {
 	power-domains = <&ps_disp0_cpu0>, <&ps_dptx_phy_ps>;
 };
@@ -43,3 +49,26 @@ &wifi0 {
 &bluetooth0 {
 	compatible = "pci14e4,5f72";
 };
+
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};
diff --git a/arch/arm64/boot/dts/apple/t603x-j514-j516.dtsi b/arch/arm64/boot/dts/apple/t603x-j514-j516.dtsi
index 517b84c18..f6fe382de 100644
--- a/arch/arm64/boot/dts/apple/t603x-j514-j516.dtsi
+++ b/arch/arm64/boot/dts/apple/t603x-j514-j516.dtsi
@@ -21,6 +21,7 @@ / {
 	chassis-type = "laptop";
 
 	aliases {
+		keyboard = &keyboard;
 		serial0 = &serial0;
 	};
 
@@ -64,3 +65,26 @@ &serial0 {
 &fpwm0 {
 	status = "okay";
 };
+
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};
diff --git a/arch/arm64/boot/dts/apple/t8112-j413.dts b/arch/arm64/boot/dts/apple/t8112-j413.dts
index 7ccfceb08..5b9bdad3d 100644
--- a/arch/arm64/boot/dts/apple/t8112-j413.dts
+++ b/arch/arm64/boot/dts/apple/t8112-j413.dts
@@ -20,6 +20,7 @@ / {
 
 	aliases {
 		bluetooth0 = &bluetooth0;
+		keyboard = &keyboard;
 		wifi0 = &wifi0;
 	};
 
@@ -93,3 +94,26 @@ &fpwm1 {
 };
 
 #include "hwmon-laptop.dtsi"
+
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};
diff --git a/arch/arm64/boot/dts/apple/t8112-j415.dts b/arch/arm64/boot/dts/apple/t8112-j415.dts
index fdc3409d2..3da132eeb 100644
--- a/arch/arm64/boot/dts/apple/t8112-j415.dts
+++ b/arch/arm64/boot/dts/apple/t8112-j415.dts
@@ -20,6 +20,7 @@ / {
 
 	aliases {
 		bluetooth0 = &bluetooth0;
+		keyboard = &keyboard;
 		wifi0 = &wifi0;
 	};
 
@@ -93,3 +94,26 @@ &fpwm1 {
 };
 
 #include "hwmon-laptop.dtsi"
+
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};
diff --git a/arch/arm64/boot/dts/apple/t8112-j493.dts b/arch/arm64/boot/dts/apple/t8112-j493.dts
index 7cea5c594..ecc057929 100644
--- a/arch/arm64/boot/dts/apple/t8112-j493.dts
+++ b/arch/arm64/boot/dts/apple/t8112-j493.dts
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0+ OR MIT
 /*
- * Apple MacBook Pro (13-inch, M1, 2022)
+ * Apple MacBook Pro (13-inch, M2, 2022)
  *
  * target-type: J493
  *
@@ -24,6 +24,7 @@ / {
 	 */
 	aliases {
 		bluetooth0 = &bluetooth0;
+		keyboard = &keyboard;
 		touchbar0 = &touchbar0;
 		wifi0 = &wifi0;
 	};
@@ -149,3 +150,26 @@ touchbar0: touchbar@0 {
 
 #include "hwmon-laptop.dtsi"
 #include "hwmon-fan.dtsi"
+
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};
diff --git a/arch/arm64/boot/dts/apple/t8122-j504.dts b/arch/arm64/boot/dts/apple/t8122-j504.dts
index 464491b55..a08a130be 100644
--- a/arch/arm64/boot/dts/apple/t8122-j504.dts
+++ b/arch/arm64/boot/dts/apple/t8122-j504.dts
@@ -18,6 +18,10 @@ / {
 	compatible = "apple,j504", "apple,t8122", "apple,arm-platform";
 	model = "Apple MacBook Pro (14-inch, M3, 2023)";
 
+	aliases {
+		keyboard = &keyboard;
+	};
+
 	led-controller {
 		compatible = "pwm-leds";
 		led-0 {
@@ -35,3 +39,25 @@ &fpwm1 {
 	status = "okay";
 };
 
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};
diff --git a/arch/arm64/boot/dts/apple/t8122-j613.dts b/arch/arm64/boot/dts/apple/t8122-j613.dts
index 51894ea70..a81326cd5 100644
--- a/arch/arm64/boot/dts/apple/t8122-j613.dts
+++ b/arch/arm64/boot/dts/apple/t8122-j613.dts
@@ -17,6 +17,10 @@ / {
 	compatible = "apple,j613", "apple,t8122", "apple,arm-platform";
 	model = "Apple MacBook Air (13-inch, M3, 2024)";
 
+	aliases {
+		keyboard = &keyboard;
+	};
+
 	led-controller {
 		compatible = "pwm-leds";
 		led-0 {
@@ -33,3 +37,26 @@ led-0 {
 &fpwm1 {
 	status = "okay";
 };
+
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};
diff --git a/arch/arm64/boot/dts/apple/t8122-j615.dts b/arch/arm64/boot/dts/apple/t8122-j615.dts
index 2a1970c1b..21bcacb6f 100644
--- a/arch/arm64/boot/dts/apple/t8122-j615.dts
+++ b/arch/arm64/boot/dts/apple/t8122-j615.dts
@@ -17,6 +17,10 @@ / {
 	compatible = "apple,j615", "apple,t8122", "apple,arm-platform";
 	model = "Apple MacBook Air (15-inch, M3, 2024)";
 
+	aliases {
+		keyboard = &keyboard;
+	};
+
 	led-controller {
 		compatible = "pwm-leds";
 		led-0 {
@@ -33,3 +37,26 @@ led-0 {
 &fpwm1 {
 	status = "okay";
 };
+
+&mtp_mbox {
+	status = "okay";
+};
+
+&mtp_dart {
+	status = "okay";
+};
+
+&mtp_dockchannel {
+	status = "okay";
+};
+
+&mtp_hid {
+	status = "okay";
+
+	keyboard: keyboard {
+		hid-country-code = <0>;
+	};
+
+	stm {
+	};
+};

-- 
2.55.0

Re: [PATCH v2 05/10] mailbox: apple: Add DockChannel FIFO controller

[Yureka Lilian]

On 9/18/26 13:06, Michael Reeves via B4 Relay wrote:
> From: Michael Reeves <michael.reeves077@gmail.com>
>
> DockChannel is a hardware FIFO used by Apple coprocessors for
> low-latency byte-stream communication with the AP.
>
> Add a mailbox controller that preallocates RX storage, tracks IRQ
> enable state in software, and reports TX completion from the TX-empty
> interrupt.
>
> Reject messages larger than the FIFO and return -EBUSY while the
> previous message is still pending. This keeps the provider usable for
> future small-message clients such as serial transports without a TX
> worker.
>
> Handle RX and TX interrupts in a thread so mailbox callbacks and locking
> run outside hard-IRQ context.
>
> Co-developed-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
> ---
>   MAINTAINERS                               |   2 +
>   drivers/mailbox/Kconfig                   |  12 +
>   drivers/mailbox/Makefile                  |   2 +
>   drivers/mailbox/apple-dockchannel.c       | 371 ++++++++++++++++++++++++++++++
>   include/linux/mailbox/apple-dockchannel.h |  29 +++
>   5 files changed, 416 insertions(+)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7fe2ebb5e..e5be5934c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2677,6 +2677,7 @@ F:	drivers/input/touchscreen/apple_z2.c
>   F:	drivers/iommu/apple-dart.c
>   F:	drivers/iommu/io-pgtable-dart.c
>   F:	drivers/irqchip/irq-apple-aic.c
> +F:	drivers/mailbox/apple-dockchannel.c
>   F:	drivers/mfd/macsmc.c
>   F:	drivers/nvme/host/apple.c
>   F:	drivers/nvmem/apple-efuses.c
> @@ -2695,6 +2696,7 @@ F:	drivers/video/backlight/apple_dwi_bl.c
>   F:	drivers/watchdog/apple_wdt.c
>   F:	include/dt-bindings/interrupt-controller/apple-aic.h
>   F:	include/dt-bindings/pinctrl/apple.h
> +F:	include/linux/mailbox/apple-dockchannel.h
>   F:	include/linux/mfd/macsmc.h
>   F:	include/linux/soc/apple/*
>   F:	include/uapi/drm/asahi_drm.h
> [...]
> diff --git a/drivers/mailbox/apple-dockchannel.c b/drivers/mailbox/apple-dockchannel.c
> new file mode 100644
> index 000000000..d0a66e1b7
> --- /dev/null
> +++ b/drivers/mailbox/apple-dockchannel.c
> @@ -0,0 +1,371 @@
> +// SPDX-License-Identifier: GPL-2.0-only OR MIT
> +/*
> + * Apple DockChannel mailbox controller
> + *
> + * Copyright The Asahi Linux Contributors
> + *
> + * DockChannel is a byte FIFO used by Apple co-processors. This driver exposes a
> + * single FIFO pair as a Linux mailbox channel and moves payload bytes with PIO.
> + * There is no DMA involved, so relaxed MMIO accessors are sufficient for the
> + * FIFO accesses themselves.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/mailbox/apple-dockchannel.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +#include <linux/unaligned.h>
> +
> +#define APPLE_DOCKCHANNEL_FIFO_SIZE	0x800
> +
> +#define IRQ_MASK			0x0
> +#define IRQ_FLAG			0x4
> +
> +#define IRQ_TX				BIT(2)
> +#define IRQ_RX				BIT(3)

The dockchannel interface used for dockchannel-uart / DebugUSB uses 
different bits here, so these should probably be read from the device 
tree if the mailbox driver is supposed to be somewhat generic.

> [...]