Re: [PATCH v3] platform/x86/amd/pmc: Detect when STB is not available

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Mon, 28 Oct 2024, Corey Hickey wrote:

> From: Corey Hickey <bugfood-c@fatooh.org>
> 
> Loading the amd_pmc module as:
> 
>     amd_pmc enable_stb=1
> 
> ...can result in the following messages in the kernel ring buffer:
> 
>     amd_pmc AMDI0009:00: SMU cmd failed. err: 0xff
>     ioremap on RAM at 0x0000000000000000 - 0x0000000000ffffff
>     WARNING: CPU: 10 PID: 2151 at arch/x86/mm/ioremap.c:217 __ioremap_caller+0x2cd/0x340
> 
> Further debugging reveals that this occurs when the requests for
> S2D_PHYS_ADDR_LOW and S2D_PHYS_ADDR_HIGH return a value of 0,
> indicating that the STB is inaccessible. To prevent the ioremap
> warning and provide clarity to the user, handle the invalid address
> and display an error message.
> 
> Link: https://lore.kernel.org/platform-driver-x86/c588ff5d-3e04-4549-9a86-284b9b4419ba@amd.com
> Fixes: 3d7d407dfb05 ("platform/x86: amd-pmc: Add support for AMD Spill to DRAM STB feature")
> Acked-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> Signed-off-by: Corey Hickey <bugfood-c@fatooh.org>
> ---
>  drivers/platform/x86/amd/pmc/pmc.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/platform/x86/amd/pmc/pmc.c b/drivers/platform/x86/amd/pmc/pmc.c
> index bbb8edb62e00..5669f94c3d06 100644
> --- a/drivers/platform/x86/amd/pmc/pmc.c
> +++ b/drivers/platform/x86/amd/pmc/pmc.c
> @@ -998,6 +998,11 @@ static int amd_pmc_s2d_init(struct amd_pmc_dev *dev)
>  	amd_pmc_send_cmd(dev, S2D_PHYS_ADDR_LOW, &phys_addr_low, dev->s2d_msg_id, true);
>  	amd_pmc_send_cmd(dev, S2D_PHYS_ADDR_HIGH, &phys_addr_hi, dev->s2d_msg_id, true);
>  
> +	if (!phys_addr_hi && !phys_addr_low) {
> +		dev_err(dev->dev, "STB is not enabled on the system; disable enable_stb or contact system vendor\n");
> +		return -EINVAL;
> +	}
> +
>  	stb_phys_addr = ((u64)phys_addr_hi << 32 | phys_addr_low);
>  
>  	/* Clear msg_port for other SMU operation */
> 

Thanks for the update,

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

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