[PATCH 0/2] Add Altera timeout bridge driver

[PATCH 0/2] Add Altera timeout bridge driver

[Vyacheslav Yurkov via B4 Relay]

This series adds support for the Altera timeout bridge IP. 

The timeout bridge connects an Avalon bus to the HPS and provides a
downstream address space for devices implemented in the FPGA. The
bridge also exposes status information and generates an interrupt when
a timeout occurs.

The driver registers the timeout bridge as a bus and allows child
devices behind the bridge to be described as the child nodes in the
device tree.

The latest bridge documentation (as of October 2026):
https://docs.altera.com/r/docs/683609/26.1/quartus-prime-pro-edition-user-guide/axi-timeout-bridge-ip

Signed-off-by: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
---
Vyacheslav Yurkov (2):
      dt-bindings: bus: Add binding for Altera AXI Timeout Bridge
      bus: add Altera timeout bridge driver

 .../bindings/bus/altera-timeout-bridge.yaml        |  82 ++++++++
 drivers/bus/Kconfig                                |  10 +
 drivers/bus/Makefile                               |   1 +
 drivers/bus/altera-timeout-bridge.c                | 219 +++++++++++++++++++++
 4 files changed, 312 insertions(+)
---
base-commit: a74306e2e676f9775457366fc047a660fbf02f26
change-id: 20261003-feature-timeout-ip-7a93630de299

Best regards,
-- 
Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>

[PATCH 1/2] dt-bindings: bus: Add binding for Altera AXI Timeout Bridge

[Vyacheslav Yurkov via B4 Relay]

From: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>

Add a device tree binding for the Altera timeout bridge, which connects
an Avalon bus to the HPS and provides an address space for child
devices with a fall back to a simple bus.

Signed-off-by: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
---
 .../bindings/bus/altera-timeout-bridge.yaml        | 82 ++++++++++++++++++++++
 1 file changed, 82 insertions(+)

diff --git a/Documentation/devicetree/bindings/bus/altera-timeout-bridge.yaml b/Documentation/devicetree/bindings/bus/altera-timeout-bridge.yaml
new file mode 100644
index 000000000000..b57a0966ba6e
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/altera-timeout-bridge.yaml
@@ -0,0 +1,82 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/bus/altera-timeout-bridge.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Altera Timeout Bridge
+
+maintainers:
+  - Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
+
+description: |
+  Altera timeout bridge bus.
+
+properties:
+  compatible:
+    items:
+      - const: altera-timeout-bridge
+      - const: simple-bus
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  ranges: true
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-parent
+  - ranges
+  - "#address-cells"
+  - "#size-cells"
+
+patternProperties:
+  "^[a-zA-Z][a-zA-Z0-9,+._-]*@[0-9a-f]+$":
+    type: object
+    description: |
+      Device connected to the timeout bridge.
+
+    required:
+      - compatible
+      - reg
+
+    additionalProperties: true
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    intc: interrupt-controller {
+        interrupt-controller;
+        #interrupt-cells = <3>;
+    };
+
+    timeout_bridge_hps@10000 {
+        compatible = "altera-timeout-bridge", "simple-bus";
+        #address-cells = <1>;
+        #size-cells = <1>;
+
+        reg = <0x10000 0xF>;
+
+        interrupts = <0 12 IRQ_TYPE_LEVEL_HIGH>;
+        interrupt-parent = <&intc>;
+
+        ranges = <0x0 0x10010 0x1000>;
+
+        timeout-device@100 {
+            compatible = "timeout-device";
+            reg = <0x100 0x10>;
+        };
+    };

-- 
2.34.1

[PATCH 2/2] bus: add Altera timeout bridge driver

[Vyacheslav Yurkov via B4 Relay]

From: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>

Add support for the Altera timeout bridge IP.

The bridge connects an Avalon bus to the HPS and monitors accesses for
timeouts. When a timeout occurs the interrupt communicates the event via
sysfs, which user space can monitor to handle it accordingly. The
address with the timeout is reported as well.

Signed-off-by: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
---
 drivers/bus/Kconfig                 |  10 ++
 drivers/bus/Makefile                |   1 +
 drivers/bus/altera-timeout-bridge.c | 219 ++++++++++++++++++++++++++++++++++++
 3 files changed, 230 insertions(+)

diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index e4b1db809187..8a4ad96742e5 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -247,6 +247,16 @@ config DA8XX_MSTPRI
 	  configuration. Allows to adjust the priorities of all master
 	  peripherals.
 
+config ALTERA_TIMEOUT_BRIDGE
+	tristate "Altera AXI Timeout Bridge bus"
+	depends on OF
+	default n
+	help
+	  Driver for Altera AXI Timeout Bridge, which can be used a bus.
+	  The subordinate devices can be connected to the bridge, which
+	  detects frozen read/write requests and notifies user space by
+	  means of a sysfs interrupt flag.
+
 source "drivers/bus/fsl-mc/Kconfig"
 source "drivers/bus/mhi/Kconfig"
 
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index a01f97fef3e8..ad4e6d7b1e49 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_UNIPHIER_SYSTEM_BUS)	+= uniphier-system-bus.o
 obj-$(CONFIG_VEXPRESS_CONFIG)	+= vexpress-config.o
 
 obj-$(CONFIG_DA8XX_MSTPRI)	+= da8xx-mstpri.o
+obj-$(CONFIG_ALTERA_TIMEOUT_BRIDGE)	+= altera-timeout-bridge.o
 
 # MHI
 obj-y				+= mhi/
diff --git a/drivers/bus/altera-timeout-bridge.c b/drivers/bus/altera-timeout-bridge.c
new file mode 100644
index 000000000000..bb44ff4a7591
--- /dev/null
+++ b/drivers/bus/altera-timeout-bridge.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Altera Timeout Bridge Bus Driver
+ *
+ * Copyright (C) 2026 Bruker Corporation
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#define ALTERA_TIMEOUT_BRIDGE_REG_TIMED_OUT_ADDRESS 0x08
+#define ALTERA_TIMEOUT_BRIDGE_REG_IRQ_STATUS_RESET 0x00
+
+struct altera_timeout_bridge_data {
+	struct device *dev;
+	struct resource *bridge_register_resource;
+	void __iomem *bridge_registers;
+	atomic_t irq_count;
+	struct kernfs_node *irq_node;
+};
+
+static ssize_t timeout_irq_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	return 0;
+}
+
+static ssize_t irq_count_show(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	struct altera_timeout_bridge_data *driver_data = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", atomic_read(&driver_data->irq_count));
+}
+
+static DEVICE_ATTR_RO(timeout_irq);
+static DEVICE_ATTR_RO(irq_count);
+
+static struct attribute *altera_timeout_bridge_sysfs_attrs[] = {
+	&dev_attr_timeout_irq.attr,
+	&dev_attr_irq_count.attr,
+	NULL /* sentinel */
+};
+
+static const struct attribute_group altera_timeout_bridge_sysfs_group = {
+	.attrs = altera_timeout_bridge_sysfs_attrs,
+};
+
+static u32
+bridge_reg_read(struct altera_timeout_bridge_data *driver_data,
+		u32 offset)
+{
+	u32 result;
+
+	result = readl(driver_data->bridge_registers + offset);
+
+	return result;
+}
+
+static void bridge_reg_write(
+	struct altera_timeout_bridge_data *driver_data,
+	int offset, u32 value)
+{
+	writel(value, driver_data->bridge_registers + offset);
+}
+
+static irqreturn_t altera_timeout_bridge_isr(int irq, void *data)
+{
+	struct altera_timeout_bridge_data *driver_data = data;
+	u32 timed_out_address;
+	resource_size_t effective_base_address;
+	resource_size_t effective_timed_out_address;
+
+	atomic_inc(&driver_data->irq_count);
+
+	// Read and print the timed-out address (encoded in the lower nibble
+	// 0x8..0xF according to AXI Timeout Bridge IP (CSR Interrupt Status Information)
+	timed_out_address = bridge_reg_read(
+		driver_data,
+		ALTERA_TIMEOUT_BRIDGE_REG_TIMED_OUT_ADDRESS);
+	effective_base_address = driver_data->bridge_register_resource->start;
+	effective_timed_out_address = effective_base_address + timed_out_address;
+	pr_err("%s: timeout at address 0x%llx\n",
+		__func__, (unsigned long long)effective_timed_out_address);
+
+	// Reset IRQ status in the bridge
+	bridge_reg_write(
+		driver_data,
+		ALTERA_TIMEOUT_BRIDGE_REG_IRQ_STATUS_RESET,
+		0x1);
+	// notify the user space
+	sysfs_notify_dirent(driver_data->irq_node);
+
+	return IRQ_HANDLED;
+}
+static int altera_timeout_bridge_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	const struct of_device_id *match;
+	const struct of_dev_auxdata *lookup = dev_get_platdata(dev);
+	struct device_node *np = dev->of_node;
+	struct altera_timeout_bridge_data *driver_data;
+	int ret = 0;
+	int irq = -1;
+
+	/*
+	 * Allow user to use driver_override to bind this driver to a
+	 * transparent bus device which has a different compatible string
+	 * that's not listed in simple_pm_bus_of_match. We don't want to do any
+	 * of the simple-pm-bus tasks for these devices, so return early.
+	 */
+	if (device_has_driver_override(&pdev->dev))
+		return 0;
+
+	match = of_match_device(dev->driver->of_match_table, dev);
+
+	/* Use a fall back logic like in simple-pm-bus */
+	if (match && match->data) {
+		if (of_property_match_string(np, "compatible", match->compatible) == 0)
+			return 0;
+		else
+			return -ENODEV;
+	}
+
+	driver_data =
+		devm_kzalloc(&pdev->dev, sizeof(*driver_data), GFP_KERNEL);
+	if (!driver_data) {
+		dev_err(&pdev->dev,
+			"%s: kzalloc failed: no memory for the driver's data, returning ENOMEM\n",
+			__func__);
+		return -ENOMEM;
+	}
+
+	driver_data->dev = dev;
+	platform_set_drvdata(pdev, driver_data);
+
+	driver_data->bridge_register_resource =
+		platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!driver_data->bridge_register_resource) {
+		dev_err(dev,
+			"%s: missing required reg binding\n",
+			__func__);
+		return -ENOENT;
+	}
+	driver_data->bridge_registers =
+		devm_ioremap_resource(dev,
+				     driver_data->bridge_register_resource);
+	if (IS_ERR(driver_data->bridge_registers)) {
+		dev_err(dev,
+			"%s: ioremap_resource failed for bridge-status MMIO, returning PTR_ERR(%ld)\n",
+			__func__, PTR_ERR(driver_data->bridge_registers));
+		return PTR_ERR(driver_data->bridge_registers);
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(dev,
+			"%s: platform_get_irq failed: %d\n", __func__, irq);
+		return irq;
+	}
+
+	ret = devm_request_irq(dev, irq,
+			       altera_timeout_bridge_isr,
+			       0,
+			       dev_name(dev),
+			       driver_data);
+	if (ret) {
+		dev_err(dev,
+			"%s: devm_request_irq failed for IRQ %d: %d\n",
+			__func__, irq, ret);
+		return ret;
+	}
+
+	ret = devm_device_add_group(dev, &altera_timeout_bridge_sysfs_group);
+	if (ret)
+		return ret;
+
+	driver_data->irq_node = sysfs_get_dirent(dev->kobj.sd, "timeout_irq");
+	if (!driver_data->irq_node)
+		return -ENOENT;
+
+	ret = devm_add_action_or_reset(dev, (void (*)(void *))sysfs_put, driver_data->irq_node);
+	if (ret)
+		return ret;
+
+	if (np)
+		of_platform_populate(np, NULL, lookup, &pdev->dev);
+
+	return 0;
+}
+
+#define ONLY_BUS	((void *) 1) /* Match if the device is only a bus. */
+
+static const struct of_device_id altera_timeout_bridge_of_match[] = {
+	{ .compatible = "altera-timeout-bridge", },
+	{ .compatible = "simple-bus",	.data = ONLY_BUS },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, altera_timeout_bridge_of_match);
+
+static struct platform_driver altera_timeout_bridge_driver = {
+	.probe = altera_timeout_bridge_probe,
+	.driver = {
+		.name = "altera-timeout-bridge",
+		.of_match_table = altera_timeout_bridge_of_match,
+	},
+};
+
+module_platform_driver(altera_timeout_bridge_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Avalon Timeout Bridge Bus");
+MODULE_AUTHOR("Vyacheslav Yurkov (V.Yurkov.EXT@bruker.com)");
+

-- 
2.34.1

Re: [PATCH 1/2] dt-bindings: bus: Add binding for Altera AXI Timeout Bridge

[Krzysztof Kozlowski]

On 03/10/2026 22:19, Vyacheslav Yurkov via B4 Relay wrote:
> From: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
> 
> Add a device tree binding for the Altera timeout bridge, which connects
> an Avalon bus to the HPS and provides an address space for child
> devices with a fall back to a simple bus.
> 
> Signed-off-by: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
> ---
>  .../bindings/bus/altera-timeout-bridge.yaml        | 82 ++++++++++++++++++++++

Filename must match compatible and compatible has completely broken
format. Please look at DT spec or any other examples how compatibles are
created.


>  1 file changed, 82 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/bus/altera-timeout-bridge.yaml b/Documentation/devicetree/bindings/bus/altera-timeout-bridge.yaml
> new file mode 100644
> index 000000000000..b57a0966ba6e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/bus/altera-timeout-bridge.yaml
> @@ -0,0 +1,82 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/bus/altera-timeout-bridge.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Altera Timeout Bridge
> +
> +maintainers:
> +  - Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
> +
> +description: |
> +  Altera timeout bridge bus.

Useless description. You keep repeating the same.

> +
> +properties:
> +  compatible:
> +    items:
> +      - const: altera-timeout-bridge
> +      - const: simple-bus

Why the fallback?

Your commit msg is also useless here, you just wrote what you did, not why.

I see no reason why generic "bus" like that should stay generic,
although you have entire commit msg to explain why this is different or
what is the versioning of this IP block.

Missing blank line.

> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  ranges: true
> +
> +  "#address-cells":
> +    const: 1
> +
> +  "#size-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - interrupt-parent
> +  - ranges
> +  - "#address-cells"
> +  - "#size-cells"
> +
> +patternProperties:

This follows properties.

> +  "^[a-zA-Z][a-zA-Z0-9,+._-]*@[0-9a-f]+$":
> +    type: object
> +    description: |
> +      Device connected to the timeout bridge.
> +
> +    required:
> +      - compatible
> +      - reg
> +
> +    additionalProperties: true
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    intc: interrupt-controller {
> +        interrupt-controller;
> +        #interrupt-cells = <3>;
> +    };

Drop, irrelevant


> +
> +    timeout_bridge_hps@10000 {

Really, this is the style you send? So the toolset - dt-check-style - or
the Coding style mean nothing and you keep sending what you have in
downstream.



Best regards,
Krzysztof

Re: [PATCH 2/2] bus: add Altera timeout bridge driver

[Krzysztof Kozlowski]

On 03/10/2026 22:19, Vyacheslav Yurkov via B4 Relay wrote:
> From: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
> 
> Add support for the Altera timeout bridge IP.
> 
> The bridge connects an Avalon bus to the HPS and monitors accesses for
> timeouts. When a timeout occurs the interrupt communicates the event via
> sysfs, which user space can monitor to handle it accordingly. The
> address with the timeout is reported as well.
> 

Neither this nor binding explains what is this hardware and where I can
find it.

> Signed-off-by: Vyacheslav Yurkov <V.Yurkov.EXT@bruker.com>
> ---
>  drivers/bus/Kconfig                 |  10 ++
>  drivers/bus/Makefile                |   1 +
>  drivers/bus/altera-timeout-bridge.c | 219 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 230 insertions(+)
> 
> diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
> index e4b1db809187..8a4ad96742e5 100644
> --- a/drivers/bus/Kconfig
> +++ b/drivers/bus/Kconfig
> @@ -247,6 +247,16 @@ config DA8XX_MSTPRI
>  	  configuration. Allows to adjust the priorities of all master
>  	  peripherals.
>  
> +config ALTERA_TIMEOUT_BRIDGE
> +	tristate "Altera AXI Timeout Bridge bus"
> +	depends on OF
> +	default n
> +	help
> +	  Driver for Altera AXI Timeout Bridge, which can be used a bus.
> +	  The subordinate devices can be connected to the bridge, which
> +	  detects frozen read/write requests and notifies user space by
> +	  means of a sysfs interrupt flag.




> +
> +static ssize_t irq_count_show(struct device *dev,
> +			      struct device_attribute *attr,
> +			      char *buf)
> +{
> +	struct altera_timeout_bridge_data *driver_data = dev_get_drvdata(dev);
> +
> +	return sysfs_emit(buf, "%d\n", atomic_read(&driver_data->irq_count));
> +}
> +
> +static DEVICE_ATTR_RO(timeout_irq);
> +static DEVICE_ATTR_RO(irq_count);

Missing ABI documentation.


> +


> +
> +#define ONLY_BUS	((void *) 1) /* Match if the device is only a bus. */
> +
> +static const struct of_device_id altera_timeout_bridge_of_match[] = {
> +	{ .compatible = "altera-timeout-bridge", },
> +	{ .compatible = "simple-bus",	.data = ONLY_BUS },

I don't understand why you want to bind to generic compatible.



> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, altera_timeout_bridge_of_match);
> +
> +static struct platform_driver altera_timeout_bridge_driver = {
> +	.probe = altera_timeout_bridge_probe,
> +	.driver = {
> +		.name = "altera-timeout-bridge",
> +		.of_match_table = altera_timeout_bridge_of_match,
> +	},
> +};
> +
> +module_platform_driver(altera_timeout_bridge_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Avalon Timeout Bridge Bus");
> +MODULE_AUTHOR("Vyacheslav Yurkov (V.Yurkov.EXT@bruker.com)");
> +
> 


Best regards,
Krzysztof