[5/6] hwmon: (k10temp) Define helper function to read CCD temp

Message ID 20230516202430.4157216-6-yazen.ghannam@amd.com
State New
Headers
Series Enhance AMD SMN Error Checking |

Commit Message

Yazen Ghannam May 16, 2023, 8:24 p.m. UTC
  The CCD temperature register is read in two places. These reads are done
using an AMD SMN access, and a number of parameters are needed for the
operation.

Move the SMN access and parameter gathering into a helper function in
order to simply the code flow. This also has a benefit of centralizing
the hardware register access in a single place in case fixes or special
decoding is required.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
 drivers/hwmon/k10temp.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)
  

Comments

Guenter Roeck May 17, 2023, 12:30 p.m. UTC | #1
On Tue, May 16, 2023 at 03:24:29PM -0500, Yazen Ghannam wrote:
> The CCD temperature register is read in two places. These reads are done
> using an AMD SMN access, and a number of parameters are needed for the
> operation.
> 
> Move the SMN access and parameter gathering into a helper function in
> order to simply the code flow. This also has a benefit of centralizing
> the hardware register access in a single place in case fixes or special
> decoding is required.
> 
> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> ---
>  drivers/hwmon/k10temp.c | 19 ++++++++++++++-----
>  1 file changed, 14 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hwmon/k10temp.c b/drivers/hwmon/k10temp.c
> index 6ea1fa62b7c1..06af1fe38af7 100644
> --- a/drivers/hwmon/k10temp.c
> +++ b/drivers/hwmon/k10temp.c
> @@ -150,6 +150,18 @@ static void read_tempreg_nb_zen(struct pci_dev *pdev, u32 *regval)
>  		*regval = 0;
>  }
>  
> +static int read_ccd_temp_reg(struct k10temp_data *data, int ccd, u32 *regval)
> +{
> +	u16 node_id = amd_pci_dev_to_node_id(data->pdev);
> +	u32 tmp;
> +
> +	if (amd_smn_read(node_id, ZEN_CCD_TEMP(data->ccd_offset, ccd), &tmp))
> +		return -EINVAL;

As mentioned before, this is not appropriate. The error code
from amd_smn_read() should be returned.

> +
> +	*regval = tmp;

This seems pointless. Why not just pass regval as parameter
to amd_smn_read() ?

This function should be reduced to

	return amd_smn_read(node_id, ZEN_CCD_TEMP(data->ccd_offset, ccd), regval));

> +	return 0;
> +}
> +
>  static long get_raw_temp(struct k10temp_data *data)
>  {
>  	u32 regval;
> @@ -214,9 +226,7 @@ static int k10temp_read_temp(struct device *dev, u32 attr, int channel,
>  				*val = 0;
>  			break;
>  		case 2 ... 13:		/* Tccd{1-12} */
> -			if (amd_smn_read(amd_pci_dev_to_node_id(data->pdev),
> -					 ZEN_CCD_TEMP(data->ccd_offset, channel - 2),
> -					 &regval))
> +			if (read_ccd_temp_reg(data, channel - 2, &regval))
>  				return -EINVAL;

Now this is really wrong, no matter what. Why bother replacing the
error code in read_ccd_temp_reg() only to replace it again ?

>  
>  			*val = (regval & ZEN_CCD_TEMP_MASK) * 125 - 49000;
> @@ -376,8 +386,7 @@ static void k10temp_get_ccd_support(struct pci_dev *pdev,
>  	int i;
>  
>  	for (i = 0; i < limit; i++) {
> -		if (amd_smn_read(amd_pci_dev_to_node_id(pdev),
> -				 ZEN_CCD_TEMP(data->ccd_offset, i), &regval))
> +		if (read_ccd_temp_reg(data, i, &regval))
>  			continue;
>  
>  		if (regval & ZEN_CCD_TEMP_VALID)
> -- 
> 2.34.1
>
  
Yazen Ghannam May 17, 2023, 2:09 p.m. UTC | #2
On 5/17/23 8:30 AM, Guenter Roeck wrote:
> On Tue, May 16, 2023 at 03:24:29PM -0500, Yazen Ghannam wrote:
>> The CCD temperature register is read in two places. These reads are done
>> using an AMD SMN access, and a number of parameters are needed for the
>> operation.
>>
>> Move the SMN access and parameter gathering into a helper function in
>> order to simply the code flow. This also has a benefit of centralizing
>> the hardware register access in a single place in case fixes or special
>> decoding is required.
>>
>> Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
>> ---
>>  drivers/hwmon/k10temp.c | 19 ++++++++++++++-----
>>  1 file changed, 14 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/hwmon/k10temp.c b/drivers/hwmon/k10temp.c
>> index 6ea1fa62b7c1..06af1fe38af7 100644
>> --- a/drivers/hwmon/k10temp.c
>> +++ b/drivers/hwmon/k10temp.c
>> @@ -150,6 +150,18 @@ static void read_tempreg_nb_zen(struct pci_dev *pdev, u32 *regval)
>>  		*regval = 0;
>>  }
>>  
>> +static int read_ccd_temp_reg(struct k10temp_data *data, int ccd, u32 *regval)
>> +{
>> +	u16 node_id = amd_pci_dev_to_node_id(data->pdev);
>> +	u32 tmp;
>> +
>> +	if (amd_smn_read(node_id, ZEN_CCD_TEMP(data->ccd_offset, ccd), &tmp))
>> +		return -EINVAL;
> 
> As mentioned before, this is not appropriate. The error code
> from amd_smn_read() should be returned.
>

Okay, will do.

>> +
>> +	*regval = tmp;
> 
> This seems pointless. Why not just pass regval as parameter
> to amd_smn_read() ?
> 
> This function should be reduced to
> 
> 	return amd_smn_read(node_id, ZEN_CCD_TEMP(data->ccd_offset, ccd), regval));
> 

Yes, will do. I think I got carried away with the "don't save invalid
value" idea. But this isn't necessary if the caller checks the return
code and avoids using the value.

>> +	return 0;
>> +}
>> +
>>  static long get_raw_temp(struct k10temp_data *data)
>>  {
>>  	u32 regval;
>> @@ -214,9 +226,7 @@ static int k10temp_read_temp(struct device *dev, u32 attr, int channel,
>>  				*val = 0;
>>  			break;
>>  		case 2 ... 13:		/* Tccd{1-12} */
>> -			if (amd_smn_read(amd_pci_dev_to_node_id(data->pdev),
>> -					 ZEN_CCD_TEMP(data->ccd_offset, channel - 2),
>> -					 &regval))
>> +			if (read_ccd_temp_reg(data, channel - 2, &regval))
>>  				return -EINVAL;
> 
> Now this is really wrong, no matter what. Why bother replacing the
> error code in read_ccd_temp_reg() only to replace it again ?
>

Understood. Will fix like the other places.

Thanks,
Yazen
  

Patch

diff --git a/drivers/hwmon/k10temp.c b/drivers/hwmon/k10temp.c
index 6ea1fa62b7c1..06af1fe38af7 100644
--- a/drivers/hwmon/k10temp.c
+++ b/drivers/hwmon/k10temp.c
@@ -150,6 +150,18 @@  static void read_tempreg_nb_zen(struct pci_dev *pdev, u32 *regval)
 		*regval = 0;
 }
 
+static int read_ccd_temp_reg(struct k10temp_data *data, int ccd, u32 *regval)
+{
+	u16 node_id = amd_pci_dev_to_node_id(data->pdev);
+	u32 tmp;
+
+	if (amd_smn_read(node_id, ZEN_CCD_TEMP(data->ccd_offset, ccd), &tmp))
+		return -EINVAL;
+
+	*regval = tmp;
+	return 0;
+}
+
 static long get_raw_temp(struct k10temp_data *data)
 {
 	u32 regval;
@@ -214,9 +226,7 @@  static int k10temp_read_temp(struct device *dev, u32 attr, int channel,
 				*val = 0;
 			break;
 		case 2 ... 13:		/* Tccd{1-12} */
-			if (amd_smn_read(amd_pci_dev_to_node_id(data->pdev),
-					 ZEN_CCD_TEMP(data->ccd_offset, channel - 2),
-					 &regval))
+			if (read_ccd_temp_reg(data, channel - 2, &regval))
 				return -EINVAL;
 
 			*val = (regval & ZEN_CCD_TEMP_MASK) * 125 - 49000;
@@ -376,8 +386,7 @@  static void k10temp_get_ccd_support(struct pci_dev *pdev,
 	int i;
 
 	for (i = 0; i < limit; i++) {
-		if (amd_smn_read(amd_pci_dev_to_node_id(pdev),
-				 ZEN_CCD_TEMP(data->ccd_offset, i), &regval))
+		if (read_ccd_temp_reg(data, i, &regval))
 			continue;
 
 		if (regval & ZEN_CCD_TEMP_VALID)