diff mbox series

[v3,1/7] platform/x86: amd-pmc: Fix command completion code

Message ID 20210628110451.4047142-2-Shyam-sundar.S-k@amd.com (mailing list archive)
State Superseded, archived
Headers show
Series updates to amd-pmc driver | expand

Commit Message

Shyam Sundar S K June 28, 2021, 11:04 a.m. UTC 
The protocol to submit a job request to SMU is to wait for
AMD_PMC_REGISTER_RESPONSE to return 1,meaning SMU is ready to take
requests. PMC driver has to make sure that the response code is always
AMD_PMC_RESULT_OK before making any command submissions.

When we submit a message to SMU, we have to wait until it processes
the request. Adding a read_poll_timeout() check as this was missing in
the existing code.

Also, add a mutex to protect amd_pmc_send_cmd() calls to SMU.

Fixes: 156ec4731cb2 ("platform/x86: amd-pmc: Add AMD platform support for S2Idle")
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
---
v2: no change
v3:
 - use mutex to protect multiple calls to SMU
 - add a switch-case to handle smu responses.

 drivers/platform/x86/amd-pmc.c | 29 +++++++++++++++++++++++++++--
 1 file changed, 27 insertions(+), 2 deletions(-)

Comments

Hans de Goede June 28, 2021, 1:59 p.m. UTC | #1 
Hi Shyam,

On 6/28/21 1:04 PM, Shyam Sundar S K wrote:
> The protocol to submit a job request to SMU is to wait for
> AMD_PMC_REGISTER_RESPONSE to return 1,meaning SMU is ready to take
> requests. PMC driver has to make sure that the response code is always
> AMD_PMC_RESULT_OK before making any command submissions.
> 
> When we submit a message to SMU, we have to wait until it processes
> the request. Adding a read_poll_timeout() check as this was missing in
> the existing code.
> 
> Also, add a mutex to protect amd_pmc_send_cmd() calls to SMU.
> 
> Fixes: 156ec4731cb2 ("platform/x86: amd-pmc: Add AMD platform support for S2Idle")
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> ---
> v2: no change
> v3:
>  - use mutex to protect multiple calls to SMU
>  - add a switch-case to handle smu responses.

I'm sorry, but this still needs a bit more work, see below.

>  drivers/platform/x86/amd-pmc.c | 29 +++++++++++++++++++++++++++--
>  1 file changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c
> index b9da58ee9b1e..f3f5f754f75c 100644
> --- a/drivers/platform/x86/amd-pmc.c
> +++ b/drivers/platform/x86/amd-pmc.c
> @@ -68,6 +68,7 @@ struct amd_pmc_dev {
>  	u32 base_addr;
>  	u32 cpu_id;
>  	struct device *dev;
> +	struct mutex lock; /* generic mutex lock */
>  #if IS_ENABLED(CONFIG_DEBUG_FS)
>  	struct dentry *dbgfs_dir;
>  #endif /* CONFIG_DEBUG_FS */
> @@ -138,9 +139,10 @@ static int amd_pmc_send_cmd(struct amd_pmc_dev *dev, bool set)
>  	u8 msg;
>  	u32 val;
>  
> +	mutex_lock(&dev->lock);
>  	/* Wait until we get a valid response */
>  	rc = readx_poll_timeout(ioread32, dev->regbase + AMD_PMC_REGISTER_RESPONSE,
> -				val, val > 0, PMC_MSG_DELAY_MIN_US,
> +				val, val != 0, PMC_MSG_DELAY_MIN_US,
>  				PMC_MSG_DELAY_MIN_US * RESPONSE_REGISTER_LOOP_MAX);
>  	if (rc) {
>  		dev_err(dev->dev, "failed to talk to SMU\n");
> @@ -156,7 +158,28 @@ static int amd_pmc_send_cmd(struct amd_pmc_dev *dev, bool set)
>  	/* Write message ID to message ID register */
>  	msg = (dev->cpu_id == AMD_CPU_ID_RN) ? MSG_OS_HINT_RN : MSG_OS_HINT_PCO;
>  	amd_pmc_reg_write(dev, AMD_PMC_REGISTER_MESSAGE, msg);
> -	return 0;
> +	/* Wait until we get a valid response */
> +	rc = readx_poll_timeout(ioread32, dev->regbase + AMD_PMC_REGISTER_RESPONSE,
> +				val, val != 0, PMC_MSG_DELAY_MIN_US,
> +				PMC_MSG_DELAY_MIN_US * RESPONSE_REGISTER_LOOP_MAX);
> +	if (rc)
> +		dev_err(dev->dev, "SMU response timed out\n");

If rc != 0 then val will still be 0, so this function will end up
returning 0 while it should return an error.

Please add a rc = -ETIME; or rc = -ETIMEDOUT + goto out_unlock here.


> +
> +	switch (val) {
> +	case AMD_PMC_RESULT_OK:
> +		break;
> +	case AMD_PMC_RESULT_CMD_REJECT_BUSY:
> +	case AMD_PMC_RESULT_CMD_REJECT_PREREQ:
> +	case AMD_PMC_RESULT_CMD_UNKNOWN:
> +	case AMD_PMC_RESULT_FAILED:
> +		dev_err(dev->dev, "SMU not ready. err: 0x%x\n", val);
> +		rc = -EBUSY;
> +		goto out_unlock;

The rc should different for different val values, e.g.
CMD_REJECT_BUSY -> -EBUSY, CMD_UNKNOWN -> EINVAL
and map the others to -EIO.

Also you should have a default case to handle the case where the hw
returns some other value (and also map that to -EIO.

Regards,

Hans



> +	}
> +
> +out_unlock:
> +	mutex_unlock(&dev->lock);
> +	return rc;
>  }
>  
>  static int __maybe_unused amd_pmc_suspend(struct device *dev)
> @@ -259,6 +282,7 @@ static int amd_pmc_probe(struct platform_device *pdev)
>  
>  	amd_pmc_dump_registers(dev);
>  
> +	mutex_init(&dev->lock);
>  	platform_set_drvdata(pdev, dev);
>  	amd_pmc_dbgfs_register(dev);
>  	return 0;
> @@ -269,6 +293,7 @@ static int amd_pmc_remove(struct platform_device *pdev)
>  	struct amd_pmc_dev *dev = platform_get_drvdata(pdev);
>  
>  	amd_pmc_dbgfs_unregister(dev);
> +	mutex_destroy(&dev->lock);
>  	return 0;
>  }
>  
>
diff mbox series

Patch

diff --git a/drivers/platform/x86/amd-pmc.c b/drivers/platform/x86/amd-pmc.c
index b9da58ee9b1e..f3f5f754f75c 100644
--- a/drivers/platform/x86/amd-pmc.c
+++ b/drivers/platform/x86/amd-pmc.c
@@ -68,6 +68,7 @@  struct amd_pmc_dev {
 	u32 base_addr;
 	u32 cpu_id;
 	struct device *dev;
+	struct mutex lock; /* generic mutex lock */
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 	struct dentry *dbgfs_dir;
 #endif /* CONFIG_DEBUG_FS */
@@ -138,9 +139,10 @@  static int amd_pmc_send_cmd(struct amd_pmc_dev *dev, bool set)
 	u8 msg;
 	u32 val;
 
+	mutex_lock(&dev->lock);
 	/* Wait until we get a valid response */
 	rc = readx_poll_timeout(ioread32, dev->regbase + AMD_PMC_REGISTER_RESPONSE,
-				val, val > 0, PMC_MSG_DELAY_MIN_US,
+				val, val != 0, PMC_MSG_DELAY_MIN_US,
 				PMC_MSG_DELAY_MIN_US * RESPONSE_REGISTER_LOOP_MAX);
 	if (rc) {
 		dev_err(dev->dev, "failed to talk to SMU\n");
@@ -156,7 +158,28 @@  static int amd_pmc_send_cmd(struct amd_pmc_dev *dev, bool set)
 	/* Write message ID to message ID register */
 	msg = (dev->cpu_id == AMD_CPU_ID_RN) ? MSG_OS_HINT_RN : MSG_OS_HINT_PCO;
 	amd_pmc_reg_write(dev, AMD_PMC_REGISTER_MESSAGE, msg);
-	return 0;
+	/* Wait until we get a valid response */
+	rc = readx_poll_timeout(ioread32, dev->regbase + AMD_PMC_REGISTER_RESPONSE,
+				val, val != 0, PMC_MSG_DELAY_MIN_US,
+				PMC_MSG_DELAY_MIN_US * RESPONSE_REGISTER_LOOP_MAX);
+	if (rc)
+		dev_err(dev->dev, "SMU response timed out\n");
+
+	switch (val) {
+	case AMD_PMC_RESULT_OK:
+		break;
+	case AMD_PMC_RESULT_CMD_REJECT_BUSY:
+	case AMD_PMC_RESULT_CMD_REJECT_PREREQ:
+	case AMD_PMC_RESULT_CMD_UNKNOWN:
+	case AMD_PMC_RESULT_FAILED:
+		dev_err(dev->dev, "SMU not ready. err: 0x%x\n", val);
+		rc = -EBUSY;
+		goto out_unlock;
+	}
+
+out_unlock:
+	mutex_unlock(&dev->lock);
+	return rc;
 }
 
 static int __maybe_unused amd_pmc_suspend(struct device *dev)
@@ -259,6 +282,7 @@  static int amd_pmc_probe(struct platform_device *pdev)
 
 	amd_pmc_dump_registers(dev);
 
+	mutex_init(&dev->lock);
 	platform_set_drvdata(pdev, dev);
 	amd_pmc_dbgfs_register(dev);
 	return 0;
@@ -269,6 +293,7 @@  static int amd_pmc_remove(struct platform_device *pdev)
 	struct amd_pmc_dev *dev = platform_get_drvdata(pdev);
 
 	amd_pmc_dbgfs_unregister(dev);
+	mutex_destroy(&dev->lock);
 	return 0;
 }