Re: [PATCH v2] platform/x86/amd/pmc: adjust amd_pmc_get_dram_size() behavior

[Mario Limonciello <mario.limonciello@amd.com>]

On 11/9/2023 00:17, Shyam Sundar S K wrote:
> After talking to the PMFW team, its understood that the "get dram size"
> mbox command would only be supported on specific platforms (like Mendocino)
> and not all. So adjust the behavior of amd_pmc_get_dram_size() function
> such that,
> 
> - if that's Rembrandt or Mendocino and the underlying PMFW knows how
> to execute the "get dram size" command it shall give the custom dram size.
> 
> - if the underlying FW does not report the dram size, we just proceed
> further and assign the default dram size.
> 
> Cc: Mark Hasemeyer <markhas@chromium.org>
> Link: https://lore.kernel.org/platform-driver-x86/3b224c62-a1d8-41bd-aced-5825f5f20e66@amd.com/
> Fixes: be8325fb3d8c ("platform/x86/amd: pmc: Get STB DRAM size from PMFW")
> Suggested-by: Sanket Goswami <Sanket.Goswami@amd.com>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> ---
> 
> v2:
> - Based on review-ilpo branch
> - Drop calling get smu version from probe.
> 
>   drivers/platform/x86/amd/pmc/pmc.c | 11 +----------
>   1 file changed, 1 insertion(+), 10 deletions(-)
> 
> diff --git a/drivers/platform/x86/amd/pmc/pmc.c b/drivers/platform/x86/amd/pmc/pmc.c
> index cd6ac04c1468..501c72c7d34c 100644
> --- a/drivers/platform/x86/amd/pmc/pmc.c
> +++ b/drivers/platform/x86/amd/pmc/pmc.c
> @@ -968,17 +968,8 @@ static int amd_pmc_get_dram_size(struct amd_pmc_dev *dev)
>   {
>   	int ret;
>   
> -	switch (dev->cpu_id) {
> -	case AMD_CPU_ID_YC:
> -		if (!(dev->major > 90 || (dev->major == 90 && dev->minor > 39))) {
> -			ret = -EINVAL;
> -			goto err_dram_size;
> -		}
> -		break;
> -	default:
> -		ret = -EINVAL;
> +	if (dev->cpu_id != AMD_CPU_ID_YC)
>   		goto err_dram_size;
> -	}

I notice that the error at err_dram_size is really noisy.  Thinking 
about how this command only works on RMB or MDN I think you should also 
downgrade it to debug.

>   
>   	ret = amd_pmc_send_cmd(dev, S2D_DRAM_SIZE, &dev->dram_size, dev->s2d_msg_id, true);
>   	if (ret || !dev->dram_size)