[PATCH] pci: pci_mvebu: Disable config access to PCI host bridge ports

[Stefan Roese]

This patch changes the PCI config routines in the Armada XP / 38x driver
to not allow access to the PCIe root ports.

While updating the Armada XP based theadorable to the latest mainline
and testing it with the DM PCI driver I noticed, that the PCI root
bridge was being configured incorrectly. Resulting in the PCIe Intel
WiFi was not working correctly in Linux. With this patch applied, all
PCIe devices work without any issues in Linux again.

Signed-off-by: Stefan Roese <sr at denx.de>
Cc: Marek Behún <marek.behun at nic.cz>
Cc: Phil Sutter <phil at nwl.cc>
Cc: Mario Six <mario.six at gdsys.cc>
---
 drivers/pci/pci_mvebu.c | 66 +++++++++++++++++------------------------
 1 file changed, 27 insertions(+), 39 deletions(-)

diff --git a/drivers/pci/pci_mvebu.c b/drivers/pci/pci_mvebu.c
index 9528e7c40ecf..46ffa8df4403 100644
--- a/drivers/pci/pci_mvebu.c
+++ b/drivers/pci/pci_mvebu.c
@@ -153,28 +153,21 @@ static int mvebu_pcie_read_config(const struct udevice *bus, pci_dev_t bdf,
 	u32 reg;
 	u32 data;
 
-	debug("PCIE CFG read:  (b,d,f)=(%2d,%2d,%2d) ",
-	      PCI_BUS(bdf), PCI_DEV(bdf), PCI_FUNC(bdf));
-
-	/* Only allow one other device besides the local one on the local bus */
-	if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) != local_dev) {
-		if (local_dev == 0 && PCI_DEV(bdf) != 1) {
-			debug("- out of range\n");
-			/*
-			 * If local dev is 0, the first other dev can
-			 * only be 1
-			 */
-			*valuep = pci_get_ff(size);
-			return 0;
-		} else if (local_dev != 0 && PCI_DEV(bdf) != 0) {
-			debug("- out of range\n");
-			/*
-			 * If local dev is not 0, the first other dev can
-			 * only be 0
-			 */
-			*valuep = pci_get_ff(size);
-			return 0;
-		}
+	debug("PCIE CFG read:  loc_bus=%d loc_dev=%d (b,d,f)=(%2d,%2d,%2d) ",
+	      local_bus, local_dev, PCI_BUS(bdf), PCI_DEV(bdf), PCI_FUNC(bdf));
+
+	/* Don't access the local host controller via this API */
+	if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) == local_dev) {
+		debug("- skipping host controller\n");
+		*valuep = pci_get_ff(size);
+		return 0;
+	}
+
+	/* If local dev is 0, the first other dev can only be 1 */
+	if (PCI_BUS(bdf) == local_bus && local_dev == 0 && PCI_DEV(bdf) != 1) {
+		debug("- out of range\n");
+		*valuep = pci_get_ff(size);
+		return 0;
 	}
 
 	/* write address */
@@ -196,25 +189,20 @@ static int mvebu_pcie_write_config(struct udevice *bus, pci_dev_t bdf,
 	int local_dev = PCI_DEV(pcie->dev);
 	u32 data;
 
-	debug("PCIE CFG write: (b,d,f)=(%2d,%2d,%2d) ",
-	      PCI_BUS(bdf), PCI_DEV(bdf), PCI_FUNC(bdf));
+	debug("PCIE CFG write: loc_bus=%d loc_dev=%d (b,d,f)=(%2d,%2d,%2d) ",
+	      local_bus, local_dev, PCI_BUS(bdf), PCI_DEV(bdf), PCI_FUNC(bdf));
 	debug("(addr,val)=(0x%04x, 0x%08lx)\n", offset, value);
 
-	/* Only allow one other device besides the local one on the local bus */
-	if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) != local_dev) {
-		if (local_dev == 0 && PCI_DEV(bdf) != 1) {
-			/*
-			 * If local dev is 0, the first other dev can
-			 * only be 1
-			 */
-			return 0;
-		} else if (local_dev != 0 && PCI_DEV(bdf) != 0) {
-			/*
-			 * If local dev is not 0, the first other dev can
-			 * only be 0
-			 */
-			return 0;
-		}
+	/* Don't access the local host controller via this API */
+	if (PCI_BUS(bdf) == local_bus && PCI_DEV(bdf) == local_dev) {
+		debug("- skipping host controller\n");
+		return 0;
+	}
+
+	/* If local dev is 0, the first other dev can only be 1 */
+	if (PCI_BUS(bdf) == local_bus && local_dev == 0 && PCI_DEV(bdf) != 1) {
+		debug("- out of range\n");
+		return 0;
 	}
 
 	writel(PCIE_CONF_ADDR(bdf, offset), pcie->base + PCIE_CONF_ADDR_OFF);
-- 
2.30.0