[PATCH 0/2] ipmi: ssif_bmc: Add support for adjustable response timeout

[PATCH 0/2] ipmi: ssif_bmc: Add support for adjustable response timeout

[Potin Lai]

The SSIF response is handled by a userspace application, which may exceed  
the default 500 ms timeout when the BMC or application is under heavy load.  
To provide flexibility, this patch introduces the `timeout-ms` property in  
the device tree binding, allowing platforms to adjust the response timeout  
as needed.  

If `timeout-ms` is not specified, the default response timeout remains  
500 ms, ensuring backward compatibility while giving platforms the option  
to configure a longer timeout when necessary. This prevents timeouts in
cases where userspace processing may take longer.

Signed-off-by: Potin Lai <potin.lai.pt@gmail.com>
---
Potin Lai (2):
      bindings: ipmi: ssif-bmc: Add property to adjust response timeout
      ipmi: ssif_bmc: Add support for adjustable response timeout

 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml | 6 ++++++
 drivers/char/ipmi/ssif_bmc.c                         | 8 +++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)
---
base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b
change-id: 20250203-ssif-response-timeout-ms-3bdb88ab337f

Best regards,
-- 
Potin Lai <potin.lai.pt@gmail.com>

[PATCH 1/2] bindings: ipmi: ssif-bmc: Add property to adjust response timeout

[Potin Lai]

The SSIF response is handled by a userspace application, which may exceed
the default 500 ms timeout when the BMC or application is under heavy load.

Add a new device tree property, `timeout-ms`, allowing platforms to adjust
the response timeout based on their specific requirements. This helps
prevent timeouts in scenarios where longer processing times are expected.

Signed-off-by: Potin Lai <potin.lai.pt@gmail.com>
---
 Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
index 02b662d780bb..c8a863d44f97 100644
--- a/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
+++ b/Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml
@@ -19,6 +19,12 @@ properties:
   reg:
     maxItems: 1
 
+  timeout-ms:
+    minimum: 0
+    maximum: 4294967295
+    default: 500
+    description: Response timeout in millisecond.
+
 required:
   - compatible
   - reg

-- 
2.31.1

[PATCH 2/2] ipmi: ssif_bmc: Add support for adjustable response timeout

[Potin Lai]

Implement support for the `timeout-ms` device tree property, allowing
platforms to adjust the userspace response timeout as needed.

If `timeout-ms` is not specified, the default response timeout remains
500 ms. This ensures compatibility while providing flexibility for
platforms that require longer timeouts due to BMC or application load.

Signed-off-by: Potin Lai <potin.lai.pt@gmail.com>
---
 drivers/char/ipmi/ssif_bmc.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
index 310f17dd9511..8f0fbc941936 100644
--- a/drivers/char/ipmi/ssif_bmc.c
+++ b/drivers/char/ipmi/ssif_bmc.c
@@ -87,6 +87,7 @@ struct ssif_bmc_ctx {
 	/* Timeout waiting for response */
 	struct timer_list       response_timer;
 	bool                    response_timer_inited;
+	u32                     response_timeout;
 	/* Flag to identify a Multi-part Read Transaction */
 	bool                    is_singlepart_read;
 	u8                      nbytes_processed;
@@ -331,7 +332,8 @@ static void handle_request(struct ssif_bmc_ctx *ssif_bmc)
 		timer_setup(&ssif_bmc->response_timer, response_timeout, 0);
 		ssif_bmc->response_timer_inited = true;
 	}
-	mod_timer(&ssif_bmc->response_timer, jiffies + msecs_to_jiffies(RESPONSE_TIMEOUT));
+	mod_timer(&ssif_bmc->response_timer, jiffies +
+		  msecs_to_jiffies(ssif_bmc->response_timeout));
 }
 
 static void calculate_response_part_pec(struct ssif_part_buffer *part)
@@ -809,6 +811,10 @@ static int ssif_bmc_probe(struct i2c_client *client)
 	if (!ssif_bmc)
 		return -ENOMEM;
 
+	if (of_property_read_u32(client->dev.of_node, "timeout-ms",
+				 &ssif_bmc->response_timeout))
+		ssif_bmc->response_timeout = RESPONSE_TIMEOUT;
+
 	spin_lock_init(&ssif_bmc->lock);
 
 	init_waitqueue_head(&ssif_bmc->wait_queue);

-- 
2.31.1

Re: [PATCH 1/2] bindings: ipmi: ssif-bmc: Add property to adjust response timeout

[Rob Herring (Arm)]

On Mon, 03 Feb 2025 21:09:13 +0800, Potin Lai wrote:
> The SSIF response is handled by a userspace application, which may exceed
> the default 500 ms timeout when the BMC or application is under heavy load.
> 
> Add a new device tree property, `timeout-ms`, allowing platforms to adjust
> the response timeout based on their specific requirements. This helps
> prevent timeouts in scenarios where longer processing times are expected.
> 
> Signed-off-by: Potin Lai <potin.lai.pt@gmail.com>
> ---
>  Documentation/devicetree/bindings/ipmi/ssif-bmc.yaml | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

Acked-by: Rob Herring (Arm) <robh@kernel.org>