PCI: dwc: Check iATU in/outbound range setup status

Make the DWC PCIe RC/EP safer and more verbose for invalid or failed
inbound and outbound iATU window setups.  Silently ignoring iATU regions
setup errors may cause unpredictable errors. For instance if a cfg or IO
window fails to be activated, then any CFG/IO requested won't reach target
PCIe devices and the corresponding accessors will return platform-specific
random values.

[bhelgaas: trim commit log]
Link: https://lore.kernel.org/r/20220624143947.8991-15-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

1 files changed, 100 insertions, 53 deletions

diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index aaf1914388b2..6993ce9e856d 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -412,7 +412,9 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 
 	dw_pcie_iatu_detect(pci);
 
-	dw_pcie_setup_rc(pp);
+	ret = dw_pcie_setup_rc(pp);
+	if (ret)
+		goto err_free_msi;
 
 	if (!dw_pcie_link_up(pci)) {
 		ret = dw_pcie_start_link(pci);
@@ -466,10 +468,10 @@ EXPORT_SYMBOL_GPL(dw_pcie_host_deinit);
 static void __iomem *dw_pcie_other_conf_map_bus(struct pci_bus *bus,
 						unsigned int devfn, int where)
 {
-	int type;
-	u32 busdev;
 	struct dw_pcie_rp *pp = bus->sysdata;
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	int type, ret;
+	u32 busdev;
 
 	/*
 	 * Checking whether the link is up here is a last line of defense
@@ -490,8 +492,10 @@ static void __iomem *dw_pcie_other_conf_map_bus(struct pci_bus *bus,
 	else
 		type = PCIE_ATU_TYPE_CFG1;
 
-
-	dw_pcie_prog_outbound_atu(pci, 0, type, pp->cfg0_base, busdev, pp->cfg0_size);
+	ret = dw_pcie_prog_outbound_atu(pci, 0, type, pp->cfg0_base, busdev,
+					pp->cfg0_size);
+	if (ret)
+		return NULL;
 
 	return pp->va_cfg0_base + where;
 }
@@ -499,33 +503,45 @@ static void __iomem *dw_pcie_other_conf_map_bus(struct pci_bus *bus,
 static int dw_pcie_rd_other_conf(struct pci_bus *bus, unsigned int devfn,
 				 int where, int size, u32 *val)
 {
-	int ret;
 	struct dw_pcie_rp *pp = bus->sysdata;
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	int ret;
 
 	ret = pci_generic_config_read(bus, devfn, where, size, val);
+	if (ret != PCIBIOS_SUCCESSFUL)
+		return ret;
 
-	if (!ret && pp->cfg0_io_shared)
-		dw_pcie_prog_outbound_atu(pci, 0, PCIE_ATU_TYPE_IO, pp->io_base,
-					  pp->io_bus_addr, pp->io_size);
+	if (pp->cfg0_io_shared) {
+		ret = dw_pcie_prog_outbound_atu(pci, 0, PCIE_ATU_TYPE_IO,
+						pp->io_base, pp->io_bus_addr,
+						pp->io_size);
+		if (ret)
+			return PCIBIOS_SET_FAILED;
+	}
 
-	return ret;
+	return PCIBIOS_SUCCESSFUL;
 }
 
 static int dw_pcie_wr_other_conf(struct pci_bus *bus, unsigned int devfn,
 				 int where, int size, u32 val)
 {
-	int ret;
 	struct dw_pcie_rp *pp = bus->sysdata;
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	int ret;
 
 	ret = pci_generic_config_write(bus, devfn, where, size, val);
+	if (ret != PCIBIOS_SUCCESSFUL)
+		return ret;
 
-	if (!ret && pp->cfg0_io_shared)
-		dw_pcie_prog_outbound_atu(pci, 0, PCIE_ATU_TYPE_IO, pp->io_base,
-					  pp->io_bus_addr, pp->io_size);
+	if (pp->cfg0_io_shared) {
+		ret = dw_pcie_prog_outbound_atu(pci, 0, PCIE_ATU_TYPE_IO,
+						pp->io_base, pp->io_bus_addr,
+						pp->io_size);
+		if (ret)
+			return PCIBIOS_SET_FAILED;
+	}
 
-	return ret;
+	return PCIBIOS_SUCCESSFUL;
 }
 
 static struct pci_ops dw_child_pcie_ops = {
@@ -552,10 +568,72 @@ static struct pci_ops dw_pcie_ops = {
 	.write = pci_generic_config_write,
 };
 
-void dw_pcie_setup_rc(struct dw_pcie_rp *pp)
+static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp)
 {
-	u32 val, ctrl, num_ctrls;
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct resource_entry *entry;
+	int i, ret;
+
+	/* Note the very first outbound ATU is used for CFG IOs */
+	if (!pci->num_ob_windows) {
+		dev_err(pci->dev, "No outbound iATU found\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Ensure all outbound windows are disabled before proceeding with
+	 * the MEM/IO ranges setups.
+	 */
+	for (i = 0; i < pci->num_ob_windows; i++)
+		dw_pcie_disable_atu(pci, PCIE_ATU_REGION_DIR_OB, i);
+
+	i = 0;
+	resource_list_for_each_entry(entry, &pp->bridge->windows) {
+		if (resource_type(entry->res) != IORESOURCE_MEM)
+			continue;
+
+		if (pci->num_ob_windows <= ++i)
+			break;
+
+		ret = dw_pcie_prog_outbound_atu(pci, i, PCIE_ATU_TYPE_MEM,
+						entry->res->start,
+						entry->res->start - entry->offset,
+						resource_size(entry->res));
+		if (ret) {
+			dev_err(pci->dev, "Failed to set MEM range %pr\n",
+				entry->res);
+			return ret;
+		}
+	}
+
+	if (pp->io_size) {
+		if (pci->num_ob_windows > ++i) {
+			ret = dw_pcie_prog_outbound_atu(pci, i, PCIE_ATU_TYPE_IO,
+							pp->io_base,
+							pp->io_bus_addr,
+							pp->io_size);
+			if (ret) {
+				dev_err(pci->dev, "Failed to set IO range %pr\n",
+					entry->res);
+				return ret;
+			}
+		} else {
+			pp->cfg0_io_shared = true;
+		}
+	}
+
+	if (pci->num_ob_windows <= i)
+		dev_warn(pci->dev, "Resources exceed number of ATU entries (%d)\n",
+			 pci->num_ob_windows);
+
+	return 0;
+}
+
+int dw_pcie_setup_rc(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	u32 val, ctrl, num_ctrls;
+	int ret;
 
 	/*
 	 * Enable DBI read-only registers for writing/updating configuration.
@@ -610,42 +688,9 @@ void dw_pcie_setup_rc(struct dw_pcie_rp *pp)
 	 * ATU, so we should not program the ATU here.
 	 */
 	if (pp->bridge->child_ops == &dw_child_pcie_ops) {
-		int i, atu_idx = 0;
-		struct resource_entry *entry;
-
-		/*
-		 * Disable all outbound windows to make sure a transaction
-		 * can't match multiple windows.
-		 */
-		for (i = 0; i < pci->num_ob_windows; i++)
-			dw_pcie_disable_atu(pci, PCIE_ATU_REGION_DIR_OB, i);
-
-		/* Get last memory resource entry */
-		resource_list_for_each_entry(entry, &pp->bridge->windows) {
-			if (resource_type(entry->res) != IORESOURCE_MEM)
-				continue;
-
-			if (pci->num_ob_windows <= ++atu_idx)
-				break;
-
-			dw_pcie_prog_outbound_atu(pci, atu_idx,
-						  PCIE_ATU_TYPE_MEM, entry->res->start,
-						  entry->res->start - entry->offset,
-						  resource_size(entry->res));
-		}
-
-		if (pp->io_size) {
-			if (pci->num_ob_windows > ++atu_idx)
-				dw_pcie_prog_outbound_atu(pci, atu_idx,
-							  PCIE_ATU_TYPE_IO, pp->io_base,
-							  pp->io_bus_addr, pp->io_size);
-			else
-				pp->cfg0_io_shared = true;
-		}
-
-		if (pci->num_ob_windows <= atu_idx)
-			dev_warn(pci->dev, "Resources exceed number of ATU entries (%d)\n",
-				 pci->num_ob_windows);
+		ret = dw_pcie_iatu_setup(pp);
+		if (ret)
+			return ret;
 	}
 
 	dw_pcie_writel_dbi(pci, PCI_BASE_ADDRESS_0, 0);
@@ -658,5 +703,7 @@ void dw_pcie_setup_rc(struct dw_pcie_rp *pp)
 	dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
 
 	dw_pcie_dbi_ro_wr_dis(pci);
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_setup_rc);