Merge branch 'pci/controller/keystone'

- Enable BAR 0 only for v3.65a to avoid Completion Timeouts that
  cause a 45 second boot delay on the v4.90a-based AM654x SoC (Siddharth
  Vadapalli)

- Avoid a NULL pointer dereference if DT failed to provide a host bridge
  memory window (Aleksandr Mishin)

* pci/controller/keystone:
  PCI: keystone: Add workaround for Errata #i2037 (AM65x SR 1.0)
  PCI: keystone: Fix NULL pointer dereference in case of DT error in ks_pcie_setup_rc_app_regs()
  PCI: keystone: Don't enable BAR 0 for AM654x
  PCI: keystone: Relocate ks_pcie_set/clear_dbi_mode()

Author: bjorn-helgaas

drivers/pci/controller/dwc/pci-keystone.c

@@ -34,6 +34,11 @@
 #define PCIE_DEVICEID_SHIFT	16
 
 /* Application registers */
+#define PID				0x000
+#define RTL				GENMASK(15, 11)
+#define RTL_SHIFT			11
+#define AM6_PCI_PG1_RTL_VER		0x15
+
 #define CMD_STATUS			0x004
 #define LTSSM_EN_VAL		        BIT(0)
 #define OB_XLAT_EN_VAL		        BIT(1)
@@ -104,6 +109,8 @@
 
 #define to_keystone_pcie(x)		dev_get_drvdata((x)->dev)
 
+#define PCI_DEVICE_ID_TI_AM654X		0xb00c
+
 struct ks_pcie_of_data {
 	enum dw_pcie_device_mode mode;
 	const struct dw_pcie_host_ops *host_ops;
@@ -245,8 +252,68 @@ static struct irq_chip ks_pcie_msi_irq_chip = {
 	.irq_unmask = ks_pcie_msi_unmask,
 };
 
+/**
+ * ks_pcie_set_dbi_mode() - Set DBI mode to access overlaid BAR mask registers
+ * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
+ *	     PCIe host controller driver information.
+ *
+ * Since modification of dbi_cs2 involves different clock domain, read the
+ * status back to ensure the transition is complete.
+ */
+static void ks_pcie_set_dbi_mode(struct keystone_pcie *ks_pcie)
+{
+	u32 val;
+
+	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	val |= DBI_CS2;
+	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
+
+	do {
+		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	} while (!(val & DBI_CS2));
+}
+
+/**
+ * ks_pcie_clear_dbi_mode() - Disable DBI mode
+ * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
+ *	     PCIe host controller driver information.
+ *
+ * Since modification of dbi_cs2 involves different clock domain, read the
+ * status back to ensure the transition is complete.
+ */
+static void ks_pcie_clear_dbi_mode(struct keystone_pcie *ks_pcie)
+{
+	u32 val;
+
+	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	val &= ~DBI_CS2;
+	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
+
+	do {
+		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
+	} while (val & DBI_CS2);
+}
+
 static int ks_pcie_msi_host_init(struct dw_pcie_rp *pp)
 {
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct keystone_pcie *ks_pcie = to_keystone_pcie(pci);
+
+	/* Configure and set up BAR0 */
+	ks_pcie_set_dbi_mode(ks_pcie);
+
+	/* Enable BAR0 */
+	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 1);
+	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, SZ_4K - 1);
+
+	ks_pcie_clear_dbi_mode(ks_pcie);
+
+	/*
+	 * For BAR0, just setting bus address for inbound writes (MSI) should
+	 * be sufficient.  Use physical address to avoid any conflicts.
+	 */
+	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, ks_pcie->app.start);
+
 	pp->msi_irq_chip = &ks_pcie_msi_irq_chip;
 	return dw_pcie_allocate_domains(pp);
 }
@@ -340,59 +407,22 @@ static const struct irq_domain_ops ks_pcie_intx_irq_domain_ops = {
 	.xlate = irq_domain_xlate_onetwocell,
 };
 
-/**
- * ks_pcie_set_dbi_mode() - Set DBI mode to access overlaid BAR mask registers
- * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
- *	     PCIe host controller driver information.
- *
- * Since modification of dbi_cs2 involves different clock domain, read the
- * status back to ensure the transition is complete.
- */
-static void ks_pcie_set_dbi_mode(struct keystone_pcie *ks_pcie)
-{
-	u32 val;
-
-	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	val |= DBI_CS2;
-	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
-
-	do {
-		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	} while (!(val & DBI_CS2));
-}
-
-/**
- * ks_pcie_clear_dbi_mode() - Disable DBI mode
- * @ks_pcie: A pointer to the keystone_pcie structure which holds the KeyStone
- *	     PCIe host controller driver information.
- *
- * Since modification of dbi_cs2 involves different clock domain, read the
- * status back to ensure the transition is complete.
- */
-static void ks_pcie_clear_dbi_mode(struct keystone_pcie *ks_pcie)
-{
-	u32 val;
-
-	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	val &= ~DBI_CS2;
-	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
-
-	do {
-		val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
-	} while (val & DBI_CS2);
-}
-
-static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie)
+static int ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie)
 {
 	u32 val;
 	u32 num_viewport = ks_pcie->num_viewport;
 	struct dw_pcie *pci = ks_pcie->pci;
 	struct dw_pcie_rp *pp = &pci->pp;
-	u64 start, end;
+	struct resource_entry *entry;
 	struct resource *mem;
+	u64 start, end;
 	int i;
 
-	mem = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM)->res;
+	entry = resource_list_first_type(&pp->bridge->windows, IORESOURCE_MEM);
+	if (!entry)
+		return -ENODEV;
+
+	mem = entry->res;
 	start = mem->start;
 	end = mem->end;
 
@@ -403,7 +433,7 @@ static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie)
 	ks_pcie_clear_dbi_mode(ks_pcie);
 
 	if (ks_pcie->is_am6)
-		return;
+		return 0;
 
 	val = ilog2(OB_WIN_SIZE);
 	ks_pcie_app_writel(ks_pcie, OB_SIZE, val);
@@ -420,6 +450,8 @@ static void ks_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie)
 	val = ks_pcie_app_readl(ks_pcie, CMD_STATUS);
 	val |= OB_XLAT_EN_VAL;
 	ks_pcie_app_writel(ks_pcie, CMD_STATUS, val);
+
+	return 0;
 }
 
 static void __iomem *ks_pcie_other_map_bus(struct pci_bus *bus,
@@ -445,44 +477,10 @@ static struct pci_ops ks_child_pcie_ops = {
 	.write = pci_generic_config_write,
 };
 
-/**
- * ks_pcie_v3_65_add_bus() - keystone add_bus post initialization
- * @bus: A pointer to the PCI bus structure.
- *
- * This sets BAR0 to enable inbound access for MSI_IRQ register
- */
-static int ks_pcie_v3_65_add_bus(struct pci_bus *bus)
-{
-	struct dw_pcie_rp *pp = bus->sysdata;
-	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
-	struct keystone_pcie *ks_pcie = to_keystone_pcie(pci);
-
-	if (!pci_is_root_bus(bus))
-		return 0;
-
-	/* Configure and set up BAR0 */
-	ks_pcie_set_dbi_mode(ks_pcie);
-
-	/* Enable BAR0 */
-	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 1);
-	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, SZ_4K - 1);
-
-	ks_pcie_clear_dbi_mode(ks_pcie);
-
-	 /*
-	  * For BAR0, just setting bus address for inbound writes (MSI) should
-	  * be sufficient.  Use physical address to avoid any conflicts.
-	  */
-	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, ks_pcie->app.start);
-
-	return 0;
-}
-
 static struct pci_ops ks_pcie_ops = {
 	.map_bus = dw_pcie_own_conf_map_bus,
 	.read = pci_generic_config_read,
 	.write = pci_generic_config_write,
-	.add_bus = ks_pcie_v3_65_add_bus,
 };
 
 /**
@@ -525,7 +523,11 @@ static int ks_pcie_start_link(struct dw_pcie *pci)
 static void ks_pcie_quirk(struct pci_dev *dev)
 {
 	struct pci_bus *bus = dev->bus;
+	struct keystone_pcie *ks_pcie;
+	struct device *bridge_dev;
 	struct pci_dev *bridge;
+	u32 val;
+
 	static const struct pci_device_id rc_pci_devids[] = {
 		{ PCI_DEVICE(PCI_VENDOR_ID_TI, PCIE_RC_K2HK),
 		 .class = PCI_CLASS_BRIDGE_PCI_NORMAL, .class_mask = ~0, },
@@ -537,6 +539,11 @@ static void ks_pcie_quirk(struct pci_dev *dev)
 		 .class = PCI_CLASS_BRIDGE_PCI_NORMAL, .class_mask = ~0, },
 		{ 0, },
 	};
+	static const struct pci_device_id am6_pci_devids[] = {
+		{ PCI_DEVICE(PCI_VENDOR_ID_TI, PCI_DEVICE_ID_TI_AM654X),
+		 .class = PCI_CLASS_BRIDGE_PCI << 8, .class_mask = ~0, },
+		{ 0, },
+	};
 
 	if (pci_is_root_bus(bus))
 		bridge = dev;
@@ -558,10 +565,36 @@ static void ks_pcie_quirk(struct pci_dev *dev)
 	 */
 	if (pci_match_id(rc_pci_devids, bridge)) {
 		if (pcie_get_readrq(dev) > 256) {
-			dev_info(&dev->dev, "limiting MRRS to 256\n");
+			dev_info(&dev->dev, "limiting MRRS to 256 bytes\n");
 			pcie_set_readrq(dev, 256);
 		}
 	}
+
+	/*
+	 * Memory transactions fail with PCI controller in AM654 PG1.0
+	 * when MRRS is set to more than 128 bytes. Force the MRRS to
+	 * 128 bytes in all downstream devices.
+	 */
+	if (pci_match_id(am6_pci_devids, bridge)) {
+		bridge_dev = pci_get_host_bridge_device(dev);
+		if (!bridge_dev && !bridge_dev->parent)
+			return;
+
+		ks_pcie = dev_get_drvdata(bridge_dev->parent);
+		if (!ks_pcie)
+			return;
+
+		val = ks_pcie_app_readl(ks_pcie, PID);
+		val &= RTL;
+		val >>= RTL_SHIFT;
+		if (val != AM6_PCI_PG1_RTL_VER)
+			return;
+
+		if (pcie_get_readrq(dev) > 128) {
+			dev_info(&dev->dev, "limiting MRRS to 128 bytes\n");
+			pcie_set_readrq(dev, 128);
+		}
+	}
 }
 DECLARE_PCI_FIXUP_ENABLE(PCI_ANY_ID, PCI_ANY_ID, ks_pcie_quirk);
 
@@ -814,7 +847,10 @@ static int __init ks_pcie_host_init(struct dw_pcie_rp *pp)
 		return ret;
 
 	ks_pcie_stop_link(pci);
-	ks_pcie_setup_rc_app_regs(ks_pcie);
+	ret = ks_pcie_setup_rc_app_regs(ks_pcie);
+	if (ret)
+		return ret;
+
 	writew(PCI_IO_RANGE_TYPE_32 | (PCI_IO_RANGE_TYPE_32 << 8),
 			pci->dbi_base + PCI_IO_BASE);