[PATCH v4 0/3] Add Amlogic general DMA

[PATCH v4 0/3] Add Amlogic general DMA

[Xianwei Zhao via B4 Relay]

Add DMA driver and bindigns for the Amlogic SoCs.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
Changes in v4:
- Support Split transfer when data len > MAX_LEN.
- When a module fails or exits, perform de-initialization.
- Some other minor modifications.
- Link to v3: https://lore.kernel.org/r/20260206-amlogic-dma-v3-0-56fb9f59ed22@amlogic.com

Changes in v3:
- Adjust the format of binding according to Frank's suggestion.
- Some code format modified according to Frank's suggestion.
- Support one prep_sg and one submit, drop multi prep_sg and one submit.
- Keep pre state when resume from pause status.
- Link to v2: https://lore.kernel.org/r/20260127-amlogic-dma-v2-0-4525d327d74d@amlogic.com

Changes in v2:
- Introduce what the DMA is used for in the A9 SoC.
- Some minor modifications were made according to Krzysztof's suggestions.
- Some modifications were made according to Neil's suggestions.
- Fix a build error.
- Link to v1: https://lore.kernel.org/r/20251216-amlogic-dma-v1-0-e289e57e96a7@amlogic.com

---
Xianwei Zhao (3):
      dt-bindings: dma: Add Amlogic A9 SoC DMA
      dma: amlogic: Add general DMA driver for A9
      MAINTAINERS: Add an entry for Amlogic DMA driver

 .../devicetree/bindings/dma/amlogic,a9-dma.yaml    |  65 +++
 MAINTAINERS                                        |   7 +
 drivers/dma/Kconfig                                |   9 +
 drivers/dma/Makefile                               |   1 +
 drivers/dma/amlogic-dma.c                          | 585 +++++++++++++++++++++
 include/dt-bindings/dma/amlogic-dma.h              |   8 +
 6 files changed, 675 insertions(+)
---
base-commit: 6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f
change-id: 20251215-amlogic-dma-79477d5cd264

Best regards,
-- 
Xianwei Zhao <xianwei.zhao@amlogic.com>



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[PATCH v4 1/3] dt-bindings: dma: Add Amlogic A9 SoC DMA

[Xianwei Zhao via B4 Relay]

From: Xianwei Zhao <xianwei.zhao@amlogic.com>

Add documentation describing the Amlogic A9 SoC DMA. And add
the properties specific values defines into a new include file.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
 .../devicetree/bindings/dma/amlogic,a9-dma.yaml    | 65 ++++++++++++++++++++++
 include/dt-bindings/dma/amlogic-dma.h              |  8 +++
 2 files changed, 73 insertions(+)

diff --git a/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml b/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml
new file mode 100644
index 000000000000..efd7b2602c33
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml
@@ -0,0 +1,65 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/dma/amlogic,a9-dma.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Amlogic general DMA controller
+
+description:
+  This is a general-purpose peripheral DMA controller. It currently supports
+  major peripherals including I2C, I3C, PIO, and CAN-BUS. Transmit and receive
+  for the same peripheral use two separate channels, controlled by different
+  register sets. I2C and I3C transfer data in 1-byte units, while PIO and
+  CAN-BUS transfer data in 4-byte units. From the controller’s perspective,
+  there is no significant difference.
+
+maintainers:
+  - Xianwei Zhao <xianwei.zhao@amlogic.com>
+
+properties:
+  compatible:
+    const: amlogic,a9-dma
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    const: sys
+
+  '#dma-cells':
+    const: 2
+
+  dma-channels:
+    maximum: 64
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - '#dma-cells'
+  - dma-channels
+
+allOf:
+  - $ref: dma-controller.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    dma-controller@fe400000{
+        compatible = "amlogic,a9-dma";
+        reg = <0xfe400000 0x4000>;
+        interrupts = <GIC_SPI 35 IRQ_TYPE_EDGE_RISING>;
+        clocks = <&clkc 45>;
+        #dma-cells = <2>;
+        dma-channels = <28>;
+    };
diff --git a/include/dt-bindings/dma/amlogic-dma.h b/include/dt-bindings/dma/amlogic-dma.h
new file mode 100644
index 000000000000..025ecc42e395
--- /dev/null
+++ b/include/dt-bindings/dma/amlogic-dma.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+
+#ifndef __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
+#define __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
+
+#define AML_DMA_TYPE_TX		0
+#define AML_DMA_TYPE_RX		1
+#endif /* __DT_BINDINGS_DMA_AMLOGIC_DMA_H__ */

-- 
2.52.0



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[PATCH v4 2/3] dma: amlogic: Add general DMA driver for A9

[Xianwei Zhao via B4 Relay]

From: Xianwei Zhao <xianwei.zhao@amlogic.com>

Amlogic A9 SoCs include a general-purpose DMA controller that can be used
by multiple peripherals, such as I2C PIO and I3C. Each peripheral group
is associated with a dedicated DMA channel in hardware.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
 drivers/dma/Kconfig       |   9 +
 drivers/dma/Makefile      |   1 +
 drivers/dma/amlogic-dma.c | 585 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 595 insertions(+)

diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 66cda7cc9f7a..8d4578513acf 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -85,6 +85,15 @@ config AMCC_PPC440SPE_ADMA
 	help
 	  Enable support for the AMCC PPC440SPe RAID engines.
 
+config AMLOGIC_DMA
+	tristate "Amlogic general DMA support"
+	depends on ARCH_MESON || COMPILE_TEST
+	select DMA_ENGINE
+	select REGMAP_MMIO
+	help
+	  Enable support for the Amlogic general DMA engines. THis DMA
+	  controller is used some Amlogic SoCs, such as A9.
+
 config APPLE_ADMAC
 	tristate "Apple ADMAC support"
 	depends on ARCH_APPLE || COMPILE_TEST
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index a54d7688392b..fc28dade5b69 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -16,6 +16,7 @@ obj-$(CONFIG_DMATEST) += dmatest.o
 obj-$(CONFIG_ALTERA_MSGDMA) += altera-msgdma.o
 obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
 obj-$(CONFIG_AMCC_PPC440SPE_ADMA) += ppc4xx/
+obj-$(CONFIG_AMLOGIC_DMA) += amlogic-dma.o
 obj-$(CONFIG_APPLE_ADMAC) += apple-admac.o
 obj-$(CONFIG_ARM_DMA350) += arm-dma350.o
 obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
diff --git a/drivers/dma/amlogic-dma.c b/drivers/dma/amlogic-dma.c
new file mode 100644
index 000000000000..e297ef82eda9
--- /dev/null
+++ b/drivers/dma/amlogic-dma.c
@@ -0,0 +1,585 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR MIT)
+/*
+ * Copyright (C) 2025 Amlogic, Inc. All rights reserved
+ * Author: Xianwei Zhao <xianwei.zhao@amlogic.com>
+ */
+
+#include <dt-bindings/dma/amlogic-dma.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "dmaengine.h"
+
+#define RCH_REG_BASE		0x0
+#define WCH_REG_BASE		0x2000
+/*
+ * Each rch (read from memory) REG offset  Rch_offset 0x0 each channel total 0x40
+ * rch addr = DMA_base + Rch_offset+ chan_id * 0x40 + reg_offset
+ */
+#define RCH_READY		0x0
+#define RCH_STATUS		0x4
+#define RCH_CFG			0x8
+#define CFG_CLEAR		BIT(25)
+#define CFG_PAUSE		BIT(26)
+#define CFG_ENABLE		BIT(27)
+#define CFG_DONE		BIT(28)
+#define RCH_ADDR		0xc
+#define RCH_LEN			0x10
+#define RCH_RD_LEN		0x14
+#define RCH_PRT			0x18
+#define RCH_SYCN_STAT		0x1c
+#define RCH_ADDR_LOW		0x20
+#define RCH_ADDR_HIGH		0x24
+/* if work on 64, it work with RCH_PRT */
+#define RCH_PTR_HIGH		0x28
+
+/*
+ * Each wch (write to memory) REG offset  Wch_offset 0x2000 each channel total 0x40
+ * wch addr = DMA_base + Wch_offset+ chan_id * 0x40 + reg_offset
+ */
+#define WCH_READY		0x0
+#define WCH_TOTAL_LEN		0x4
+#define WCH_CFG			0x8
+#define WCH_ADDR		0xc
+#define WCH_LEN			0x10
+#define WCH_RD_LEN		0x14
+#define WCH_PRT			0x18
+#define WCH_CMD_CNT		0x1c
+#define WCH_ADDR_LOW		0x20
+#define WCH_ADDR_HIGH		0x24
+/* if work on 64, it work with RCH_PRT */
+#define WCH_PTR_HIGH		0x28
+
+/* DMA controller reg */
+#define RCH_INT_MASK		0x1000
+#define WCH_INT_MASK		0x1004
+#define CLEAR_W_BATCH		0x1014
+#define CLEAR_RCH		0x1024
+#define CLEAR_WCH		0x1028
+#define RCH_ACTIVE		0x1038
+#define WCH_ACTIVE		0x103c
+#define RCH_DONE		0x104c
+#define WCH_DONE		0x1050
+#define RCH_ERR			0x1060
+#define RCH_LEN_ERR		0x1064
+#define WCH_ERR			0x1068
+#define DMA_BATCH_END		0x1078
+#define WCH_EOC_DONE		0x1088
+#define WDMA_RESP_ERR		0x1098
+#define UPT_PKT_SYNC		0x10a8
+#define RCHN_CFG		0x10ac
+#define WCHN_CFG		0x10b0
+#define MEM_PD_CFG		0x10b4
+#define MEM_BUS_CFG		0x10b8
+#define DMA_GMV_CFG		0x10bc
+#define DMA_GMR_CFG		0x10c0
+
+#define DMA_MAX_LINK		8
+#define MAX_CHAN_ID		32
+#define SG_MAX_LEN		GENMASK(26, 0)
+
+struct aml_dma_sg_link {
+#define LINK_LEN		GENMASK(26, 0)
+#define LINK_IRQ		BIT(27)
+#define LINK_EOC		BIT(28)
+#define LINK_LOOP		BIT(29)
+#define LINK_ERR		BIT(30)
+#define LINK_OWNER		BIT(31)
+	u32 ctl;
+	u64 address;
+	u32 revered;
+} __packed;
+
+struct aml_dma_chan {
+	struct dma_chan			chan;
+	struct dma_async_tx_descriptor	desc;
+	struct aml_dma_dev		*aml_dma;
+	struct aml_dma_sg_link		*sg_link;
+	dma_addr_t			sg_link_phys;
+	int				sg_link_cnt;
+	int				data_len;
+	enum dma_status			pre_status;
+	enum dma_status			status;
+	enum dma_transfer_direction	direction;
+	int				chan_id;
+	/* reg_base (direction + chan_id) */
+	int				reg_offs;
+};
+
+struct aml_dma_dev {
+	struct dma_device		dma_device;
+	void __iomem			*base;
+	struct regmap			*regmap;
+	struct clk			*clk;
+	int				irq;
+	struct platform_device		*pdev;
+	struct aml_dma_chan		*aml_rch[MAX_CHAN_ID];
+	struct aml_dma_chan		*aml_wch[MAX_CHAN_ID];
+	unsigned int			chan_nr;
+	unsigned int			chan_used;
+	struct aml_dma_chan		aml_chans[]__counted_by(chan_nr);
+};
+
+static struct aml_dma_chan *to_aml_dma_chan(struct dma_chan *chan)
+{
+	return container_of(chan, struct aml_dma_chan, chan);
+}
+
+static dma_cookie_t aml_dma_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	return dma_cookie_assign(tx);
+}
+
+static int aml_dma_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+	size_t size = size_mul(sizeof(struct aml_dma_sg_link), DMA_MAX_LINK);
+
+	aml_chan->sg_link = dma_alloc_coherent(aml_dma->dma_device.dev, size,
+					       &aml_chan->sg_link_phys, GFP_KERNEL);
+	if (!aml_chan->sg_link)
+		return  -ENOMEM;
+
+	/* offset is the same RCH_CFG and WCH_CFG */
+	regmap_update_bits(aml_dma->regmap, aml_chan->reg_offs + RCH_CFG, CFG_CLEAR, CFG_CLEAR);
+	aml_chan->status = DMA_COMPLETE;
+	dma_async_tx_descriptor_init(&aml_chan->desc, chan);
+	aml_chan->desc.tx_submit = aml_dma_tx_submit;
+	regmap_update_bits(aml_dma->regmap, aml_chan->reg_offs + RCH_CFG, CFG_CLEAR, 0);
+
+	return 0;
+}
+
+static void aml_dma_free_chan_resources(struct dma_chan *chan)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+
+	aml_chan->status = DMA_COMPLETE;
+	dma_free_coherent(aml_dma->dma_device.dev,
+			  sizeof(struct aml_dma_sg_link) * DMA_MAX_LINK,
+			  aml_chan->sg_link, aml_chan->sg_link_phys);
+}
+
+/* DMA transfer state  update how many data reside it */
+static enum dma_status aml_dma_tx_status(struct dma_chan *chan,
+					 dma_cookie_t cookie,
+					 struct dma_tx_state *txstate)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+	u32 residue, done;
+
+	regmap_read(aml_dma->regmap, aml_chan->reg_offs + RCH_RD_LEN, &done);
+	residue = aml_chan->data_len - done;
+	dma_set_tx_state(txstate, chan->completed_cookie, chan->cookie,
+			 residue);
+
+	return aml_chan->status;
+}
+
+static struct dma_async_tx_descriptor *aml_dma_prep_slave_sg
+		(struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction direction,
+		unsigned long flags, void *context)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+	struct aml_dma_sg_link *sg_link;
+	struct scatterlist *sg;
+	int idx = 0;
+	u64 paddr;
+	u32 reg, link_count, avail, chan_id;
+	u32 i;
+
+	if (aml_chan->direction != direction) {
+		dev_err(aml_dma->dma_device.dev, "direction not support\n");
+		return NULL;
+	}
+
+	switch (aml_chan->status) {
+	case DMA_IN_PROGRESS:
+		dev_err(aml_dma->dma_device.dev, "not support multi tx_desciptor\n");
+		return NULL;
+
+	case DMA_COMPLETE:
+		aml_chan->data_len = 0;
+		chan_id = aml_chan->chan_id;
+		reg = (direction == DMA_DEV_TO_MEM) ? WCH_INT_MASK : RCH_INT_MASK;
+		regmap_update_bits(aml_dma->regmap, reg, BIT(chan_id), BIT(chan_id));
+
+		break;
+	default:
+		dev_err(aml_dma->dma_device.dev, "status error\n");
+		return NULL;
+	}
+
+	link_count = sg_nents_for_dma(sgl, sg_len, SG_MAX_LEN);
+
+	if (link_count > DMA_MAX_LINK) {
+		dev_err(aml_dma->dma_device.dev,
+			"maximum number of sg exceeded: %d > %d\n",
+			sg_len, DMA_MAX_LINK);
+		aml_chan->status = DMA_ERROR;
+		return NULL;
+	}
+
+	aml_chan->status = DMA_IN_PROGRESS;
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		avail = sg_dma_len(sg);
+		paddr = sg->dma_address;
+		while (avail > SG_MAX_LEN) {
+			sg_link = &aml_chan->sg_link[idx++];
+			/* set dma address and len  to sglink*/
+			sg_link->address = paddr;
+			sg_link->ctl = FIELD_PREP(LINK_LEN, SG_MAX_LEN);
+			paddr = paddr + SG_MAX_LEN;
+			avail = avail - SG_MAX_LEN;
+		}
+		sg_link = &aml_chan->sg_link[idx++];
+		/* set dma address and len  to sglink*/
+		sg_link->address = paddr;
+		sg_link->ctl = FIELD_PREP(LINK_LEN, avail);
+
+		aml_chan->data_len += sg_dma_len(sg);
+	}
+	aml_chan->sg_link_cnt = idx;
+
+	return &aml_chan->desc;
+}
+
+static int aml_dma_pause_chan(struct dma_chan *chan)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+
+	regmap_update_bits(aml_dma->regmap, aml_chan->reg_offs + RCH_CFG, CFG_PAUSE, CFG_PAUSE);
+	aml_chan->pre_status = aml_chan->status;
+	aml_chan->status = DMA_PAUSED;
+
+	return 0;
+}
+
+static int aml_dma_resume_chan(struct dma_chan *chan)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+
+	regmap_update_bits(aml_dma->regmap, aml_chan->reg_offs + RCH_CFG, CFG_PAUSE, 0);
+	aml_chan->status = aml_chan->pre_status;
+
+	return 0;
+}
+
+static int aml_dma_terminate_all(struct dma_chan *chan)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+	int chan_id = aml_chan->chan_id;
+
+	aml_dma_pause_chan(chan);
+	regmap_update_bits(aml_dma->regmap, aml_chan->reg_offs + RCH_CFG, CFG_CLEAR, CFG_CLEAR);
+
+	if (aml_chan->direction == DMA_MEM_TO_DEV)
+		regmap_update_bits(aml_dma->regmap, RCH_INT_MASK, BIT(chan_id), BIT(chan_id));
+	else if (aml_chan->direction == DMA_DEV_TO_MEM)
+		regmap_update_bits(aml_dma->regmap, WCH_INT_MASK, BIT(chan_id), BIT(chan_id));
+
+	aml_chan->status = DMA_COMPLETE;
+
+	return 0;
+}
+
+static void aml_dma_enable_chan(struct dma_chan *chan)
+{
+	struct aml_dma_chan *aml_chan = to_aml_dma_chan(chan);
+	struct aml_dma_dev *aml_dma = aml_chan->aml_dma;
+	struct aml_dma_sg_link *sg_link;
+	int chan_id = aml_chan->chan_id;
+	int idx = aml_chan->sg_link_cnt - 1;
+
+	/* the last sg set eoc flag */
+	sg_link = &aml_chan->sg_link[idx];
+	sg_link->ctl |= LINK_EOC;
+	if (aml_chan->direction == DMA_MEM_TO_DEV) {
+		regmap_write(aml_dma->regmap, aml_chan->reg_offs + RCH_ADDR,
+			     aml_chan->sg_link_phys);
+		regmap_write(aml_dma->regmap, aml_chan->reg_offs + RCH_LEN, aml_chan->data_len);
+		regmap_update_bits(aml_dma->regmap, RCH_INT_MASK, BIT(chan_id), 0);
+		/* for rch (tx) need set cfg 0 to trigger start */
+		regmap_write(aml_dma->regmap, aml_chan->reg_offs + RCH_CFG, 0);
+	} else if (aml_chan->direction == DMA_DEV_TO_MEM) {
+		regmap_write(aml_dma->regmap, aml_chan->reg_offs + WCH_ADDR,
+			     aml_chan->sg_link_phys);
+		regmap_write(aml_dma->regmap, aml_chan->reg_offs + WCH_LEN, aml_chan->data_len);
+		regmap_update_bits(aml_dma->regmap, WCH_INT_MASK, BIT(chan_id), 0);
+	}
+}
+
+static irqreturn_t aml_dma_interrupt_handler(int irq, void *dev_id)
+{
+	struct aml_dma_dev *aml_dma = dev_id;
+	struct aml_dma_chan *aml_chan;
+	u32 done, eoc_done, err, err_l, end;
+	int i = 0;
+
+	/* deal with rch normal complete and error */
+	regmap_read(aml_dma->regmap, RCH_DONE, &done);
+	regmap_read(aml_dma->regmap, RCH_ERR, &err);
+	regmap_read(aml_dma->regmap, RCH_LEN_ERR, &err_l);
+	err = err | err_l;
+
+	done = done | err;
+
+	while (done) {
+		i = ffs(done) - 1;
+		aml_chan = aml_dma->aml_rch[i];
+		regmap_write(aml_dma->regmap, CLEAR_RCH, BIT(aml_chan->chan_id));
+		if (!aml_chan) {
+			dev_err(aml_dma->dma_device.dev, "idx %d rch not initialized\n", i);
+			done &= ~BIT(i);
+			continue;
+		}
+		aml_chan->status = (err & (1 << i)) ? DMA_ERROR : DMA_COMPLETE;
+		dma_cookie_complete(&aml_chan->desc);
+		dmaengine_desc_get_callback_invoke(&aml_chan->desc, NULL);
+		done &= ~BIT(i);
+	}
+
+	/* deal with wch normal complete and error */
+	regmap_read(aml_dma->regmap, DMA_BATCH_END, &end);
+	if (end)
+		regmap_write(aml_dma->regmap, CLEAR_W_BATCH, end);
+
+	regmap_read(aml_dma->regmap, WCH_DONE, &done);
+	regmap_read(aml_dma->regmap, WCH_EOC_DONE, &eoc_done);
+	done = done | eoc_done;
+
+	regmap_read(aml_dma->regmap, WCH_ERR, &err);
+	regmap_read(aml_dma->regmap, WDMA_RESP_ERR, &err_l);
+	err = err | err_l;
+
+	done = done | err;
+	i = 0;
+	while (done) {
+		i = ffs(done) - 1;
+		aml_chan = aml_dma->aml_wch[i];
+		regmap_write(aml_dma->regmap, CLEAR_WCH, BIT(aml_chan->chan_id));
+		if (!aml_chan) {
+			dev_err(aml_dma->dma_device.dev, "idx %d wch not initialized\n", i);
+			done &= ~BIT(i);
+			continue;
+		}
+		aml_chan->status = (err & (1 << i)) ? DMA_ERROR : DMA_COMPLETE;
+		dma_cookie_complete(&aml_chan->desc);
+		dmaengine_desc_get_callback_invoke(&aml_chan->desc, NULL);
+		done &= ~BIT(i);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static struct dma_chan *aml_of_dma_xlate(struct of_phandle_args *dma_spec, struct of_dma *ofdma)
+{
+	struct aml_dma_dev *aml_dma = (struct aml_dma_dev *)ofdma->of_dma_data;
+	struct aml_dma_chan *aml_chan = NULL;
+	u32 type;
+	u32 phy_chan_id;
+
+	if (dma_spec->args_count != 2)
+		return NULL;
+
+	type = dma_spec->args[0];
+	phy_chan_id = dma_spec->args[1];
+
+	if (phy_chan_id >= MAX_CHAN_ID)
+		return NULL;
+
+	if (type == AML_DMA_TYPE_TX) {
+		aml_chan = aml_dma->aml_rch[phy_chan_id];
+		if (!aml_chan) {
+			if (aml_dma->chan_used >= aml_dma->chan_nr) {
+				dev_err(aml_dma->dma_device.dev, "some dma clients err used\n");
+				return NULL;
+			}
+			aml_chan = &aml_dma->aml_chans[aml_dma->chan_used];
+			aml_dma->chan_used++;
+			aml_chan->direction = DMA_MEM_TO_DEV;
+			aml_chan->chan_id = phy_chan_id;
+			aml_chan->reg_offs = RCH_REG_BASE + 0x40 * aml_chan->chan_id;
+			aml_dma->aml_rch[phy_chan_id] = aml_chan;
+		}
+	} else if (type == AML_DMA_TYPE_RX) {
+		aml_chan = aml_dma->aml_wch[phy_chan_id];
+		if (!aml_chan) {
+			if (aml_dma->chan_used >= aml_dma->chan_nr) {
+				dev_err(aml_dma->dma_device.dev, "some dma clients err used\n");
+				return NULL;
+			}
+			aml_chan = &aml_dma->aml_chans[aml_dma->chan_used];
+			aml_dma->chan_used++;
+			aml_chan->direction = DMA_DEV_TO_MEM;
+			aml_chan->chan_id = phy_chan_id;
+			aml_chan->reg_offs = WCH_REG_BASE + 0x40 * aml_chan->chan_id;
+			aml_dma->aml_wch[phy_chan_id] = aml_chan;
+		}
+	} else {
+		dev_err(aml_dma->dma_device.dev, "type %d not supported\n", type);
+		return NULL;
+	}
+
+	return dma_get_slave_channel(&aml_chan->chan);
+}
+
+static int aml_dma_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct dma_device *dma_dev;
+	struct aml_dma_dev *aml_dma;
+	int ret, i, len;
+	u32 chan_nr;
+
+	const struct regmap_config aml_regmap_config = {
+		.reg_bits = 32,
+		.val_bits = 32,
+		.reg_stride = 4,
+		.max_register = 0x3000,
+	};
+
+	ret = of_property_read_u32(np, "dma-channels", &chan_nr);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "failed to read dma-channels\n");
+
+	len = sizeof(struct aml_dma_dev) + sizeof(struct aml_dma_chan) * chan_nr;
+	aml_dma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
+	if (!aml_dma)
+		return -ENOMEM;
+
+	aml_dma->chan_nr = chan_nr;
+
+	aml_dma->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(aml_dma->base))
+		return PTR_ERR(aml_dma->base);
+
+	aml_dma->regmap = devm_regmap_init_mmio(&pdev->dev, aml_dma->base,
+						&aml_regmap_config);
+	if (IS_ERR_OR_NULL(aml_dma->regmap))
+		return PTR_ERR(aml_dma->regmap);
+
+	aml_dma->clk = devm_clk_get_enabled(&pdev->dev, NULL);
+	if (IS_ERR(aml_dma->clk))
+		return PTR_ERR(aml_dma->clk);
+
+	aml_dma->irq = platform_get_irq(pdev, 0);
+
+	aml_dma->pdev = pdev;
+	aml_dma->dma_device.dev = &pdev->dev;
+
+	dma_dev = &aml_dma->dma_device;
+	INIT_LIST_HEAD(&dma_dev->channels);
+
+	/* Initialize channel parameters */
+	for (i = 0; i < chan_nr; i++) {
+		struct aml_dma_chan *aml_chan = &aml_dma->aml_chans[i];
+
+		aml_chan->aml_dma = aml_dma;
+		aml_chan->chan.device = &aml_dma->dma_device;
+		dma_cookie_init(&aml_chan->chan);
+
+		/* Add the channel to aml_chan list */
+		list_add_tail(&aml_chan->chan.device_node,
+			      &aml_dma->dma_device.channels);
+	}
+	aml_dma->chan_used = 0;
+
+	dma_set_max_seg_size(dma_dev->dev, SG_MAX_LEN);
+
+	dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
+	dma_dev->device_alloc_chan_resources = aml_dma_alloc_chan_resources;
+	dma_dev->device_free_chan_resources = aml_dma_free_chan_resources;
+	dma_dev->device_tx_status = aml_dma_tx_status;
+	dma_dev->device_prep_slave_sg = aml_dma_prep_slave_sg;
+
+	dma_dev->device_pause = aml_dma_pause_chan;
+	dma_dev->device_resume = aml_dma_resume_chan;
+	dma_dev->device_terminate_all = aml_dma_terminate_all;
+	dma_dev->device_issue_pending = aml_dma_enable_chan;
+	/* PIO 4 bytes and I2C 1 byte */
+	dma_dev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | BIT(DMA_SLAVE_BUSWIDTH_1_BYTE);
+	dma_dev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+	ret = dmaenginem_async_device_register(dma_dev);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret, "failed to register dmaenginem\n");
+
+	ret = of_dma_controller_register(np, aml_of_dma_xlate, aml_dma);
+	if (ret)
+		goto err_dmaenginem_register;
+
+	regmap_write(aml_dma->regmap, RCH_INT_MASK, 0xffffffff);
+	regmap_write(aml_dma->regmap, WCH_INT_MASK, 0xffffffff);
+
+	ret = devm_request_irq(&pdev->dev, aml_dma->irq, aml_dma_interrupt_handler,
+			       IRQF_SHARED, dev_name(&pdev->dev), aml_dma);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to reqest_irq\n");
+		goto err_of_dma_controller;
+	}
+
+	platform_set_drvdata(pdev, aml_dma);
+
+	return 0;
+
+err_of_dma_controller:
+	of_dma_controller_free(np);
+err_dmaenginem_register:
+	dma_async_device_unregister(dma_dev);
+
+	return ret;
+}
+
+static void aml_dma_remove(struct platform_device *pdev)
+{
+	struct aml_dma_dev *aml_dma = platform_get_drvdata(pdev);
+
+	of_dma_controller_free((&pdev->dev)->of_node);
+	dma_async_device_unregister(&aml_dma->dma_device);
+}
+
+static const struct of_device_id aml_dma_ids[] = {
+	{ .compatible = "amlogic,a9-dma", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, aml_dma_ids);
+
+static struct platform_driver aml_dma_driver = {
+	.probe		= aml_dma_probe,
+	.remove		= aml_dma_remove,
+	.driver		= {
+		.name	= "aml-dma",
+		.of_match_table = aml_dma_ids,
+	},
+};
+
+module_platform_driver(aml_dma_driver);
+
+MODULE_DESCRIPTION("GENERAL DMA driver for Amlogic");
+MODULE_AUTHOR("Xianwei Zhao <xianwei.zhao@amlogic.com>");
+MODULE_LICENSE("GPL");

-- 
2.52.0



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[PATCH v4 3/3] MAINTAINERS: Add an entry for Amlogic DMA driver

[Xianwei Zhao via B4 Relay]

From: Xianwei Zhao <xianwei.zhao@amlogic.com>

Add Amlogic DMA controller entry to MAINTAINERS to clarify
the maintainers.

Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 55af015174a5..e9c52dfba2df 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1316,6 +1316,13 @@ F:	Documentation/devicetree/bindings/perf/amlogic,g12-ddr-pmu.yaml
 F:	drivers/perf/amlogic/
 F:	include/soc/amlogic/
 
+AMLOGIC DMA DRIVER
+M:	Xianwei Zhao <xianwei.zhao@amlogic.com>
+L:	linux-amlogic@lists.infradead.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml
+F:	drivers/dma/amlogic-dma.c
+
 AMLOGIC ISP DRIVER
 M:	Keke Li <keke.li@amlogic.com>
 L:	linux-media@vger.kernel.org

-- 
2.52.0



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Re: [PATCH v4 1/3] dt-bindings: dma: Add Amlogic A9 SoC DMA

[Krzysztof Kozlowski]

On Fri, Feb 27, 2026 at 07:20:53AM +0000, Xianwei Zhao wrote:
> Add documentation describing the Amlogic A9 SoC DMA. And add
> the properties specific values defines into a new include file.
> 
> Signed-off-by: Xianwei Zhao <xianwei.zhao@amlogic.com>
> ---
>  .../devicetree/bindings/dma/amlogic,a9-dma.yaml    | 65 ++++++++++++++++++++++
>  include/dt-bindings/dma/amlogic-dma.h              |  8 +++
>  2 files changed, 73 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml b/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml
> new file mode 100644
> index 000000000000..efd7b2602c33
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml
> @@ -0,0 +1,65 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/dma/amlogic,a9-dma.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Amlogic general DMA controller
> +
> +description:
> +  This is a general-purpose peripheral DMA controller. It currently supports
> +  major peripherals including I2C, I3C, PIO, and CAN-BUS. Transmit and receive
> +  for the same peripheral use two separate channels, controlled by different
> +  register sets. I2C and I3C transfer data in 1-byte units, while PIO and
> +  CAN-BUS transfer data in 4-byte units. From the controller’s perspective,
> +  there is no significant difference.
> +
> +maintainers:
> +  - Xianwei Zhao <xianwei.zhao@amlogic.com>
> +
> +properties:
> +  compatible:
> +    const: amlogic,a9-dma
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    const: sys
> +
> +  '#dma-cells':
> +    const: 2
> +
> +  dma-channels:
> +    maximum: 64
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - clocks
> +  - '#dma-cells'
> +  - dma-channels
> +
> +allOf:
> +  - $ref: dma-controller.yaml#
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    dma-controller@fe400000{
> +        compatible = "amlogic,a9-dma";
> +        reg = <0xfe400000 0x4000>;
> +        interrupts = <GIC_SPI 35 IRQ_TYPE_EDGE_RISING>;
> +        clocks = <&clkc 45>;
> +        #dma-cells = <2>;
> +        dma-channels = <28>;
> +    };
> diff --git a/include/dt-bindings/dma/amlogic-dma.h b/include/dt-bindings/dma/amlogic-dma.h

Filename must be the same as binding file.

> new file mode 100644
> index 000000000000..025ecc42e395
> --- /dev/null
> +++ b/include/dt-bindings/dma/amlogic-dma.h
> @@ -0,0 +1,8 @@
> +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
> +
> +#ifndef __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
> +#define __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
> +
> +#define AML_DMA_TYPE_TX		0
> +#define AML_DMA_TYPE_RX		1

You sure you need AML prefix? Your clock constants do not have AML
prefixes. What other constants do you expect here?

Best regards,
Krzysztof


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Re: [PATCH v4 1/3] dt-bindings: dma: Add Amlogic A9 SoC DMA

[Xianwei Zhao]

Hi Krzysztof,
    Thanks for your reply.

On 2026/2/27 17:18, Krzysztof Kozlowski wrote:
> On Fri, Feb 27, 2026 at 07:20:53AM +0000, Xianwei Zhao wrote:
>> Add documentation describing the Amlogic A9 SoC DMA. And add
>> the properties specific values defines into a new include file.
>>
>> Signed-off-by: Xianwei Zhao<xianwei.zhao@amlogic.com>
>> ---
>>   .../devicetree/bindings/dma/amlogic,a9-dma.yaml    | 65 ++++++++++++++++++++++
>>   include/dt-bindings/dma/amlogic-dma.h              |  8 +++
>>   2 files changed, 73 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml b/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml
>> new file mode 100644
>> index 000000000000..efd7b2602c33
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/dma/amlogic,a9-dma.yaml
>> @@ -0,0 +1,65 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id:http://devicetree.org/schemas/dma/amlogic,a9-dma.yaml#
>> +$schema:http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Amlogic general DMA controller
>> +
>> +description:
>> +  This is a general-purpose peripheral DMA controller. It currently supports
>> +  major peripherals including I2C, I3C, PIO, and CAN-BUS. Transmit and receive
>> +  for the same peripheral use two separate channels, controlled by different
>> +  register sets. I2C and I3C transfer data in 1-byte units, while PIO and
>> +  CAN-BUS transfer data in 4-byte units. From the controller’s perspective,
>> +  there is no significant difference.
>> +
>> +maintainers:
>> +  - Xianwei Zhao<xianwei.zhao@amlogic.com>
>> +
>> +properties:
>> +  compatible:
>> +    const: amlogic,a9-dma
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    maxItems: 1
>> +
>> +  clock-names:
>> +    const: sys
>> +
>> +  '#dma-cells':
>> +    const: 2
>> +
>> +  dma-channels:
>> +    maximum: 64
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - interrupts
>> +  - clocks
>> +  - '#dma-cells'
>> +  - dma-channels
>> +
>> +allOf:
>> +  - $ref: dma-controller.yaml#
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +    dma-controller@fe400000{
>> +        compatible = "amlogic,a9-dma";
>> +        reg = <0xfe400000 0x4000>;
>> +        interrupts = <GIC_SPI 35 IRQ_TYPE_EDGE_RISING>;
>> +        clocks = <&clkc 45>;
>> +        #dma-cells = <2>;
>> +        dma-channels = <28>;
>> +    };
>> diff --git a/include/dt-bindings/dma/amlogic-dma.h b/include/dt-bindings/dma/amlogic-dma.h
> Filename must be the same as binding file.
>

Will do.

>> new file mode 100644
>> index 000000000000..025ecc42e395
>> --- /dev/null
>> +++ b/include/dt-bindings/dma/amlogic-dma.h
>> @@ -0,0 +1,8 @@
>> +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
>> +
>> +#ifndef __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
>> +#define __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
>> +
>> +#define AML_DMA_TYPE_TX              0
>> +#define AML_DMA_TYPE_RX              1
> You sure you need AML prefix? Your clock constants do not have AML
> prefixes. What other constants do you expect here?
> 

I will delete AML prefix in next version.

> Best regards,
> Krzysztof

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Re: [PATCH v4 1/3] dt-bindings: dma: Add Amlogic A9 SoC DMA

[Krzysztof Kozlowski]

On 27/02/2026 10:43, Xianwei Zhao wrote:
>>> new file mode 100644
>>> index 000000000000..025ecc42e395
>>> --- /dev/null
>>> +++ b/include/dt-bindings/dma/amlogic-dma.h
>>> @@ -0,0 +1,8 @@
>>> +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
>>> +
>>> +#ifndef __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
>>> +#define __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
>>> +
>>> +#define AML_DMA_TYPE_TX              0
>>> +#define AML_DMA_TYPE_RX              1
>> You sure you need AML prefix? Your clock constants do not have AML
>> prefixes. What other constants do you expect here?
>>
> 
> I will delete AML prefix in next version.

I assume this is an argument to "dma" phandle (cells), so maybe should
be "DMA_TX/RX"?

Best regards,
Krzysztof

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Re: [PATCH v4 1/3] dt-bindings: dma: Add Amlogic A9 SoC DMA

[Xianwei Zhao]

On 2026/2/27 17:44, Krzysztof Kozlowski wrote:
> On 27/02/2026 10:43, Xianwei Zhao wrote:
>>>> new file mode 100644
>>>> index 000000000000..025ecc42e395
>>>> --- /dev/null
>>>> +++ b/include/dt-bindings/dma/amlogic-dma.h
>>>> @@ -0,0 +1,8 @@
>>>> +/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
>>>> +
>>>> +#ifndef __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
>>>> +#define __DT_BINDINGS_DMA_AMLOGIC_DMA_H__
>>>> +
>>>> +#define AML_DMA_TYPE_TX              0
>>>> +#define AML_DMA_TYPE_RX              1
>>> You sure you need AML prefix? Your clock constants do not have AML
>>> prefixes. What other constants do you expect here?
>>>
>> I will delete AML prefix in next version.
> I assume this is an argument to "dma" phandle (cells), so maybe should
> be "DMA_TX/RX"?
> 

Thank you for your suggestion. I'll use it.

> Best regards,
> Krzysztof

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Re: [PATCH v4 2/3] dma: amlogic: Add general DMA driver for A9

[Dan Carpenter]

Hi Xianwei,

kernel test robot noticed the following build warnings:

url:    https://github.com/intel-lab-lkp/linux/commits/Xianwei-Zhao-via-B4-Relay/dt-bindings-dma-Add-Amlogic-A9-SoC-DMA/20260227-152743
base:   6de23f81a5e08be8fbf5e8d7e9febc72a5b5f27f
patch link:    https://lore.kernel.org/r/20260227-amlogic-dma-v4-2-f25e4614e9b7%40amlogic.com
patch subject: [PATCH v4 2/3] dma: amlogic: Add general DMA driver for A9
config: arm-randconfig-r073-20260228 (https://download.01.org/0day-ci/archive/20260302/202603020642.3hq2CxZ7-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
smatch version: v0.5.0-8994-gd50c5a4c

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202603020642.3hq2CxZ7-lkp@intel.com/

New smatch warnings:
drivers/dma/amlogic-dma.c:354 aml_dma_interrupt_handler() warn: variable dereferenced before check 'aml_chan' (see line 353)
drivers/dma/amlogic-dma.c:483 aml_dma_probe() warn: passing zero to 'PTR_ERR'

Old smatch warnings:
drivers/dma/amlogic-dma.c:384 aml_dma_interrupt_handler() warn: variable dereferenced before check 'aml_chan' (see line 383)

vim +/aml_chan +354 drivers/dma/amlogic-dma.c

c01d15789f1d15b Xianwei Zhao 2026-02-27  335  static irqreturn_t aml_dma_interrupt_handler(int irq, void *dev_id)
c01d15789f1d15b Xianwei Zhao 2026-02-27  336  {
c01d15789f1d15b Xianwei Zhao 2026-02-27  337  	struct aml_dma_dev *aml_dma = dev_id;
c01d15789f1d15b Xianwei Zhao 2026-02-27  338  	struct aml_dma_chan *aml_chan;
c01d15789f1d15b Xianwei Zhao 2026-02-27  339  	u32 done, eoc_done, err, err_l, end;
c01d15789f1d15b Xianwei Zhao 2026-02-27  340  	int i = 0;
c01d15789f1d15b Xianwei Zhao 2026-02-27  341  
c01d15789f1d15b Xianwei Zhao 2026-02-27  342  	/* deal with rch normal complete and error */
c01d15789f1d15b Xianwei Zhao 2026-02-27  343  	regmap_read(aml_dma->regmap, RCH_DONE, &done);
c01d15789f1d15b Xianwei Zhao 2026-02-27  344  	regmap_read(aml_dma->regmap, RCH_ERR, &err);
c01d15789f1d15b Xianwei Zhao 2026-02-27  345  	regmap_read(aml_dma->regmap, RCH_LEN_ERR, &err_l);
c01d15789f1d15b Xianwei Zhao 2026-02-27  346  	err = err | err_l;
c01d15789f1d15b Xianwei Zhao 2026-02-27  347  
c01d15789f1d15b Xianwei Zhao 2026-02-27  348  	done = done | err;
c01d15789f1d15b Xianwei Zhao 2026-02-27  349  
c01d15789f1d15b Xianwei Zhao 2026-02-27  350  	while (done) {
c01d15789f1d15b Xianwei Zhao 2026-02-27  351  		i = ffs(done) - 1;
c01d15789f1d15b Xianwei Zhao 2026-02-27  352  		aml_chan = aml_dma->aml_rch[i];
c01d15789f1d15b Xianwei Zhao 2026-02-27 @353  		regmap_write(aml_dma->regmap, CLEAR_RCH, BIT(aml_chan->chan_id));
                                                                                                     ^^^^^^^^^^^^^^^^^^
Move this dereference

c01d15789f1d15b Xianwei Zhao 2026-02-27 @354  		if (!aml_chan) {
                                                             ^^^^^^^^
after this NULL check?

c01d15789f1d15b Xianwei Zhao 2026-02-27  355  			dev_err(aml_dma->dma_device.dev, "idx %d rch not initialized\n", i);
c01d15789f1d15b Xianwei Zhao 2026-02-27  356  			done &= ~BIT(i);
c01d15789f1d15b Xianwei Zhao 2026-02-27  357  			continue;
c01d15789f1d15b Xianwei Zhao 2026-02-27  358  		}
c01d15789f1d15b Xianwei Zhao 2026-02-27  359  		aml_chan->status = (err & (1 << i)) ? DMA_ERROR : DMA_COMPLETE;
c01d15789f1d15b Xianwei Zhao 2026-02-27  360  		dma_cookie_complete(&aml_chan->desc);
c01d15789f1d15b Xianwei Zhao 2026-02-27  361  		dmaengine_desc_get_callback_invoke(&aml_chan->desc, NULL);
c01d15789f1d15b Xianwei Zhao 2026-02-27  362  		done &= ~BIT(i);
c01d15789f1d15b Xianwei Zhao 2026-02-27  363  	}
c01d15789f1d15b Xianwei Zhao 2026-02-27  364  
c01d15789f1d15b Xianwei Zhao 2026-02-27  365  	/* deal with wch normal complete and error */
c01d15789f1d15b Xianwei Zhao 2026-02-27  366  	regmap_read(aml_dma->regmap, DMA_BATCH_END, &end);
c01d15789f1d15b Xianwei Zhao 2026-02-27  367  	if (end)
c01d15789f1d15b Xianwei Zhao 2026-02-27  368  		regmap_write(aml_dma->regmap, CLEAR_W_BATCH, end);
c01d15789f1d15b Xianwei Zhao 2026-02-27  369  
c01d15789f1d15b Xianwei Zhao 2026-02-27  370  	regmap_read(aml_dma->regmap, WCH_DONE, &done);
c01d15789f1d15b Xianwei Zhao 2026-02-27  371  	regmap_read(aml_dma->regmap, WCH_EOC_DONE, &eoc_done);
c01d15789f1d15b Xianwei Zhao 2026-02-27  372  	done = done | eoc_done;
c01d15789f1d15b Xianwei Zhao 2026-02-27  373  
c01d15789f1d15b Xianwei Zhao 2026-02-27  374  	regmap_read(aml_dma->regmap, WCH_ERR, &err);
c01d15789f1d15b Xianwei Zhao 2026-02-27  375  	regmap_read(aml_dma->regmap, WDMA_RESP_ERR, &err_l);
c01d15789f1d15b Xianwei Zhao 2026-02-27  376  	err = err | err_l;
c01d15789f1d15b Xianwei Zhao 2026-02-27  377  
c01d15789f1d15b Xianwei Zhao 2026-02-27  378  	done = done | err;
c01d15789f1d15b Xianwei Zhao 2026-02-27  379  	i = 0;
c01d15789f1d15b Xianwei Zhao 2026-02-27  380  	while (done) {
c01d15789f1d15b Xianwei Zhao 2026-02-27  381  		i = ffs(done) - 1;
c01d15789f1d15b Xianwei Zhao 2026-02-27  382  		aml_chan = aml_dma->aml_wch[i];
c01d15789f1d15b Xianwei Zhao 2026-02-27  383  		regmap_write(aml_dma->regmap, CLEAR_WCH, BIT(aml_chan->chan_id));
c01d15789f1d15b Xianwei Zhao 2026-02-27  384  		if (!aml_chan) {

Same.

c01d15789f1d15b Xianwei Zhao 2026-02-27  385  			dev_err(aml_dma->dma_device.dev, "idx %d wch not initialized\n", i);
c01d15789f1d15b Xianwei Zhao 2026-02-27  386  			done &= ~BIT(i);
c01d15789f1d15b Xianwei Zhao 2026-02-27  387  			continue;
c01d15789f1d15b Xianwei Zhao 2026-02-27  388  		}
c01d15789f1d15b Xianwei Zhao 2026-02-27  389  		aml_chan->status = (err & (1 << i)) ? DMA_ERROR : DMA_COMPLETE;
c01d15789f1d15b Xianwei Zhao 2026-02-27  390  		dma_cookie_complete(&aml_chan->desc);
c01d15789f1d15b Xianwei Zhao 2026-02-27  391  		dmaengine_desc_get_callback_invoke(&aml_chan->desc, NULL);
c01d15789f1d15b Xianwei Zhao 2026-02-27  392  		done &= ~BIT(i);
c01d15789f1d15b Xianwei Zhao 2026-02-27  393  	}
c01d15789f1d15b Xianwei Zhao 2026-02-27  394  
c01d15789f1d15b Xianwei Zhao 2026-02-27  395  	return IRQ_HANDLED;
c01d15789f1d15b Xianwei Zhao 2026-02-27  396  }

[ snip ]

c01d15789f1d15b Xianwei Zhao 2026-02-27  450  static int aml_dma_probe(struct platform_device *pdev)
c01d15789f1d15b Xianwei Zhao 2026-02-27  451  {
c01d15789f1d15b Xianwei Zhao 2026-02-27  452  	struct device_node *np = pdev->dev.of_node;
c01d15789f1d15b Xianwei Zhao 2026-02-27  453  	struct dma_device *dma_dev;
c01d15789f1d15b Xianwei Zhao 2026-02-27  454  	struct aml_dma_dev *aml_dma;
c01d15789f1d15b Xianwei Zhao 2026-02-27  455  	int ret, i, len;
c01d15789f1d15b Xianwei Zhao 2026-02-27  456  	u32 chan_nr;
c01d15789f1d15b Xianwei Zhao 2026-02-27  457  
c01d15789f1d15b Xianwei Zhao 2026-02-27  458  	const struct regmap_config aml_regmap_config = {
c01d15789f1d15b Xianwei Zhao 2026-02-27  459  		.reg_bits = 32,
c01d15789f1d15b Xianwei Zhao 2026-02-27  460  		.val_bits = 32,
c01d15789f1d15b Xianwei Zhao 2026-02-27  461  		.reg_stride = 4,
c01d15789f1d15b Xianwei Zhao 2026-02-27  462  		.max_register = 0x3000,
c01d15789f1d15b Xianwei Zhao 2026-02-27  463  	};
c01d15789f1d15b Xianwei Zhao 2026-02-27  464  
c01d15789f1d15b Xianwei Zhao 2026-02-27  465  	ret = of_property_read_u32(np, "dma-channels", &chan_nr);
c01d15789f1d15b Xianwei Zhao 2026-02-27  466  	if (ret)
c01d15789f1d15b Xianwei Zhao 2026-02-27  467  		return dev_err_probe(&pdev->dev, ret, "failed to read dma-channels\n");
c01d15789f1d15b Xianwei Zhao 2026-02-27  468  
c01d15789f1d15b Xianwei Zhao 2026-02-27  469  	len = sizeof(struct aml_dma_dev) + sizeof(struct aml_dma_chan) * chan_nr;
c01d15789f1d15b Xianwei Zhao 2026-02-27  470  	aml_dma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
c01d15789f1d15b Xianwei Zhao 2026-02-27  471  	if (!aml_dma)
c01d15789f1d15b Xianwei Zhao 2026-02-27  472  		return -ENOMEM;
c01d15789f1d15b Xianwei Zhao 2026-02-27  473  
c01d15789f1d15b Xianwei Zhao 2026-02-27  474  	aml_dma->chan_nr = chan_nr;
c01d15789f1d15b Xianwei Zhao 2026-02-27  475  
c01d15789f1d15b Xianwei Zhao 2026-02-27  476  	aml_dma->base = devm_platform_ioremap_resource(pdev, 0);
c01d15789f1d15b Xianwei Zhao 2026-02-27  477  	if (IS_ERR(aml_dma->base))
c01d15789f1d15b Xianwei Zhao 2026-02-27  478  		return PTR_ERR(aml_dma->base);
c01d15789f1d15b Xianwei Zhao 2026-02-27  479  
c01d15789f1d15b Xianwei Zhao 2026-02-27  480  	aml_dma->regmap = devm_regmap_init_mmio(&pdev->dev, aml_dma->base,
c01d15789f1d15b Xianwei Zhao 2026-02-27  481  						&aml_regmap_config);
c01d15789f1d15b Xianwei Zhao 2026-02-27  482  	if (IS_ERR_OR_NULL(aml_dma->regmap))

This should just be if (IS_ERR(aml_dma->regmap)) since
devm_regmap_init_mmio() can't return NULL.
https://staticthinking.wordpress.com/2022/08/01/mixing-error-pointers-and-null/


c01d15789f1d15b Xianwei Zhao 2026-02-27 @483  		return PTR_ERR(aml_dma->regmap);
c01d15789f1d15b Xianwei Zhao 2026-02-27  484  
c01d15789f1d15b Xianwei Zhao 2026-02-27  485  	aml_dma->clk = devm_clk_get_enabled(&pdev->dev, NULL);
c01d15789f1d15b Xianwei Zhao 2026-02-27  486  	if (IS_ERR(aml_dma->clk))
c01d15789f1d15b Xianwei Zhao 2026-02-27  487  		return PTR_ERR(aml_dma->clk);
c01d15789f1d15b Xianwei Zhao 2026-02-27  488  
c01d15789f1d15b Xianwei Zhao 2026-02-27  489  	aml_dma->irq = platform_get_irq(pdev, 0);
c01d15789f1d15b Xianwei Zhao 2026-02-27  490  
c01d15789f1d15b Xianwei Zhao 2026-02-27  491  	aml_dma->pdev = pdev;
c01d15789f1d15b Xianwei Zhao 2026-02-27  492  	aml_dma->dma_device.dev = &pdev->dev;
c01d15789f1d15b Xianwei Zhao 2026-02-27  493  
c01d15789f1d15b Xianwei Zhao 2026-02-27  494  	dma_dev = &aml_dma->dma_device;
c01d15789f1d15b Xianwei Zhao 2026-02-27  495  	INIT_LIST_HEAD(&dma_dev->channels);

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki


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