Re: [PATCH] nvme: put some AMD PCIE downstream NVME device to simple suspend/resume path

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Apr 13, 2021 at 05:00:41PM +0800, Prike Liang wrote:
> The NVME device pluged in some AMD PCIE root port will resume timeout
> from s2idle which caused by NVME power CFG lost in the SMU FW restore.
> This issue can be workaround by using PCIe power set with simple
> suspend/resume process path instead of APST. In the onwards ASIC will
> try do the NVME shutdown save and restore in the BIOS and still need PCIe
> power setting to resume from RTD3 for s2idle.
> 
> Signed-off-by: Prike Liang <Prike.Liang@amd.com>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
> Cc: <stable@vger.kernel.org> # 5.11+
> ---
>  drivers/nvme/host/pci.c |  5 +++++
>  drivers/pci/quirks.c    | 10 ++++++++++
>  include/linux/pci.h     |  2 ++
>  include/linux/pci_ids.h |  1 +
>  4 files changed, 18 insertions(+)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 6bad4d4..dd46d9e 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2832,6 +2832,7 @@ static bool nvme_acpi_storage_d3(struct pci_dev *dev)
>  {
>  	struct acpi_device *adev;
>  	struct pci_dev *root;
> +	struct pci_dev *rdev;
>  	acpi_handle handle;
>  	acpi_status status;
>  	u8 val;
> @@ -2845,6 +2846,10 @@ static bool nvme_acpi_storage_d3(struct pci_dev *dev)
>  	if (!root)
>  		return false;
>  
> +	rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
> +	if (rdev->dev_flags & PCI_DEV_FLAGS_AMD_NVME_SIMPLE_SUSPEND)
> +		return NVME_QUIRK_SIMPLE_SUSPEND;
> +
>  	adev = ACPI_COMPANION(&root->dev);
>  	if (!adev)
>  		return false;
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 653660e3..0b175ce 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -312,6 +312,16 @@ static void quirk_nopciamd(struct pci_dev *dev)
>  }
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD,	PCI_DEVICE_ID_AMD_8151_0,	quirk_nopciamd);
>  
> +static void quirk_amd_nvme_fixup(struct pci_dev *dev)
> +{
> +	struct pci_dev *rdev;
> +
> +	dev->dev_flags |= PCI_DEV_FLAGS_AMD_NVME_SIMPLE_SUSPEND;
> +	pci_info(dev, "AMD simple suspend opt enabled\n");
> +
> +}
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CZN_RP, quirk_amd_nvme_fixup);
> +
>  /* Triton requires workarounds to be used by the drivers */
>  static void quirk_triton(struct pci_dev *dev)
>  {
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 53f4904..a6e1b1b 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -227,6 +227,8 @@ enum pci_dev_flags {
>  	PCI_DEV_FLAGS_NO_FLR_RESET = (__force pci_dev_flags_t) (1 << 10),
>  	/* Don't use Relaxed Ordering for TLPs directed at this device */
>  	PCI_DEV_FLAGS_NO_RELAXED_ORDERING = (__force pci_dev_flags_t) (1 << 11),
> +	/* AMD simple suspend opt quirk */
> +	PCI_DEV_FLAGS_AMD_NVME_SIMPLE_SUSPEND = (__force pci_dev_flags_t) (1 << 12),
>  };
>  
>  enum pci_irq_reroute_variant {
> diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
> index d8156a5..a82443f 100644
> --- a/include/linux/pci_ids.h
> +++ b/include/linux/pci_ids.h
> @@ -602,6 +602,7 @@
>  #define PCI_DEVICE_ID_AMD_HUDSON2_SMBUS		0x780b
>  #define PCI_DEVICE_ID_AMD_HUDSON2_IDE		0x780c
>  #define PCI_DEVICE_ID_AMD_KERNCZ_SMBUS  0x790b
> +#define PCI_DEVICE_ID_AMD_CZN_RP	0x1630

Why add this here when it is not needed in this file?  Please read the
top of the file...

thanks,

greg k-h

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