[PATCH v4 1/2] PCI: add AMD PCIe quirk for nvme shutdown opt

[Prike Liang]

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.

In this preparation patch add a PCIe quirk for the AMD.

Cc: <stable at vger.kernel.org> # 5.11+
Signed-off-by: Prike Liang <Prike.Liang at amd.com>
Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k at amd.com>
[ck: split patches for nvme and pcie]
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
---
Changes in v2:
Fix the patch format and check chip root complex DID instead of PCIe RP
to avoid the storage device plugged in internal PCIe RP by USB adaptor.

Changes in v3:
According to Christoph Hellwig do NVME PCIe related identify opt better 
in PCIe quirk driver rather than in NVME module.

Changes in v4:
Split the fix to PCIe and NVMe part and then call the pci_dev_put() put 
the device reference count and finally refine the commit info.
---
drivers/pci/quirks.c | 10 ++++++++++
 include/linux/pci.h  |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 653660e3..f95c8b2 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, 0x1630, 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 {
-- 
2.7.4