linux-kernel - Re: [PATCH v2 5/6] hwmon: (k10temp) Define helper function to read CCD temp

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Date:   Thu, 15 Jun 2023 19:22:03 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Yazen Ghannam <yazen.ghannam@....com>, x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        markgross@...nel.org, hdegoede@...hat.com,
        Shyam-sundar.S-k@....com, linux-edac@...r.kernel.org,
        clemens@...isch.de, jdelvare@...e.com, linux-hwmon@...r.kernel.org,
        mario.limonciello@....com, babu.moger@....com
Subject: Re: [PATCH v2 5/6] hwmon: (k10temp) Define helper function to read
 CCD temp

On 6/15/23 09:03, 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@....com>

Acked-by: Guenter Roeck <linux@...ck-us.net>

> ---
> Link:
> https://lore.kernel.org/r/20230516202430.4157216-6-yazen.ghannam@amd.com
> 
> v1->v2:
> * Address comments from Guenter.
> 
>   drivers/hwmon/k10temp.c | 14 +++++++++-----
>   1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/hwmon/k10temp.c b/drivers/hwmon/k10temp.c
> index 70f7b77e6ece..dfbba8b72f43 100644
> --- a/drivers/hwmon/k10temp.c
> +++ b/drivers/hwmon/k10temp.c
> @@ -150,6 +150,13 @@ 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);
> +
> +	return amd_smn_read(node_id, ZEN_CCD_TEMP(data->ccd_offset, ccd), regval);
> +}
> +
>   static long get_raw_temp(struct k10temp_data *data)
>   {
>   	u32 regval;
> @@ -215,9 +222,7 @@ static int k10temp_read_temp(struct device *dev, u32 attr, int channel,
>   				*val = 0;
>   			break;
>   		case 2 ... 13:		/* Tccd{1-12} */
> -			ret = amd_smn_read(amd_pci_dev_to_node_id(data->pdev),
> -					   ZEN_CCD_TEMP(data->ccd_offset, channel - 2),
> -					   &regval);
> +			ret = read_ccd_temp_reg(data, channel - 2, &regval);
>   
>   			if (ret)
>   				return ret;
> @@ -389,8 +394,7 @@ static void k10temp_get_ccd_support(struct pci_dev *pdev,
>   		 * the register value. And this will incorrectly pass the TEMP_VALID
>   		 * bit check.
>   		 */
> -		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)