[PATCH V2] PCI: Move VMD ASPM/LTR fix to PCI quirk

[David E. Box]

In commit f492edb40b54 ("PCI: vmd: Add quirk to configure PCIe ASPM and
LTR") the VMD driver calls pci_enabled_link_state as a callback from
pci_bus_walk. Both will acquire the pci_bus_sem lock leading to a lockdep
warning. Instead of doing the pci_bus_walk, move the fix to quirks.c using
DECLARE_PCI_FIXUP_FINAL.

Fixes: f492edb40b54 ("PCI: vmd: Add quirk to configure PCIe ASPM and LTR")
Suggested-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: David E. Box <david.e.box@xxxxxxxxxxxxxxx>
---

V2 - Instead of adding a lock flag argument to pci_enabled_link_state, move
     the fix to quirks.c

 drivers/pci/controller/vmd.c | 55 +--------------------------
 drivers/pci/quirks.c         | 72 ++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 54 deletions(-)

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index 990630ec57c6..47fa3e5f2dc5 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -66,22 +66,11 @@ enum vmd_features {
 	 * interrupt handling.
 	 */
 	VMD_FEAT_CAN_BYPASS_MSI_REMAP		= (1 << 4),
-
-	/*
-	 * Enable ASPM on the PCIE root ports and set the default LTR of the
-	 * storage devices on platforms where these values are not configured by
-	 * BIOS. This is needed for laptops, which require these settings for
-	 * proper power management of the SoC.
-	 */
-	VMD_FEAT_BIOS_PM_QUIRK		= (1 << 5),
 };
 
-#define VMD_BIOS_PM_QUIRK_LTR	0x1003	/* 3145728 ns */
-
 #define VMD_FEATS_CLIENT	(VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP |	\
 				 VMD_FEAT_HAS_BUS_RESTRICTIONS |	\
-				 VMD_FEAT_OFFSET_FIRST_VECTOR |		\
-				 VMD_FEAT_BIOS_PM_QUIRK)
+				 VMD_FEAT_OFFSET_FIRST_VECTOR)
 
 static DEFINE_IDA(vmd_instance_ida);
 
@@ -724,46 +713,6 @@ static void vmd_copy_host_bridge_flags(struct pci_host_bridge *root_bridge,
 	vmd_bridge->native_dpc = root_bridge->native_dpc;
 }
 
-/*
- * Enable ASPM and LTR settings on devices that aren't configured by BIOS.
- */
-static int vmd_pm_enable_quirk(struct pci_dev *pdev, void *userdata)
-{
-	unsigned long features = *(unsigned long *)userdata;
-	u16 ltr = VMD_BIOS_PM_QUIRK_LTR;
-	u32 ltr_reg;
-	int pos;
-
-	if (!(features & VMD_FEAT_BIOS_PM_QUIRK))
-		return 0;
-
-	pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL);
-
-	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR);
-	if (!pos)
-		return 0;
-
-	/*
-	 * Skip if the max snoop LTR is non-zero, indicating BIOS has set it
-	 * so the LTR quirk is not needed.
-	 */
-	pci_read_config_dword(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, &ltr_reg);
-	if (!!(ltr_reg & (PCI_LTR_VALUE_MASK | PCI_LTR_SCALE_MASK)))
-		return 0;
-
-	/*
-	 * Set the default values to the maximum required by the platform to
-	 * allow the deepest power management savings. Write as a DWORD where
-	 * the lower word is the max snoop latency and the upper word is the
-	 * max non-snoop latency.
-	 */
-	ltr_reg = (ltr << 16) | ltr;
-	pci_write_config_dword(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, ltr_reg);
-	pci_info(pdev, "VMD: Default LTR value set by driver\n");
-
-	return 0;
-}
-
 static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 {
 	struct pci_sysdata *sd = &vmd->sysdata;
@@ -936,8 +885,6 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
 
 	pci_assign_unassigned_bus_resources(vmd->bus);
 
-	pci_walk_bus(vmd->bus, vmd_pm_enable_quirk, &features);
-
 	/*
 	 * VMD root buses are virtual and don't return true on pci_is_pcie()
 	 * and will fail pcie_bus_configure_settings() early. It can instead be
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 44cab813bf95..2d86623f96e3 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -6023,3 +6023,75 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2d, dpc_log_size);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a2f, dpc_log_size);
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x9a31, dpc_log_size);
 #endif
+
+#ifdef CONFIG_VMD
+/*
+ * Enable ASPM on the PCIE root ports under VMD and set the default LTR of the
+ * storage devices on platforms where these values are not configured by BIOS.
+ * This is needed for laptops, which require these settings for proper power
+ * management of the SoC.
+ */
+#define VMD_DEVICE_LTR	0x1003	/* 3145728 ns */
+static void quirk_intel_vmd(struct pci_dev *pdev)
+{
+	struct pci_dev *parent;
+	u16 ltr = VMD_DEVICE_LTR;
+	u32 ltr_reg;
+	int pos;
+
+	/* Check in VMD domain */
+	if (pci_domain_nr(pdev->bus) < 0x10000)
+		return;
+
+	/* Get Root Port */
+	parent = pci_upstream_bridge(pdev);
+	if (!parent || parent->vendor != PCI_VENDOR_ID_INTEL)
+		return;
+
+	/* Get VMD Host Bridge */
+	parent = to_pci_dev(parent->dev.parent);
+	if (!parent)
+		return;
+
+	/* Get RAID controller */
+	parent = to_pci_dev(parent->dev.parent);
+	if (!parent)
+		return;
+
+	switch (parent->device) {
+	case 0x467f:
+	case 0x4c3d:
+	case 0xa77f:
+	case 0x7d0b:
+	case 0xad0b:
+	case 0x9a0b:
+		break;
+	default:
+		return;
+	}
+
+	pci_enable_link_state(pdev, PCIE_LINK_STATE_ALL);
+
+	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR);
+	if (!pos)
+		return;
+
+	/* Skip if the max snoop LTR is non-zero, indicating BIOS has set it */
+	pci_read_config_dword(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, &ltr_reg);
+	if (!!(ltr_reg & (PCI_LTR_VALUE_MASK | PCI_LTR_SCALE_MASK)))
+		return;
+
+	/*
+	 * Set the LTR values to the maximum required by the platform to
+	 * allow the deepest power management savings. Write as a DWORD where
+	 * the lower word is the max snoop latency and the upper word is the
+	 * max non-snoop latency.
+	 */
+	ltr_reg = (ltr << 16) | ltr;
+	pci_write_config_dword(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, ltr_reg);
+	pci_info(pdev, "LTR set by VMD PCI quick\n");
+
+}
+DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_ANY_ID, PCI_ANY_ID,
+			      PCI_CLASS_STORAGE_EXPRESS, 0, quirk_intel_vmd);
+#endif
-- 
2.34.1