[U-Boot] [PATCH] pci: tegra: fix DM conversion issues on Tegra20

[Stephen Warren]

From: Stephen Warren <swarren at nvidia.com>

Tegra20's PCIe controller has a couple of quirks. There are workarounds in
the driver for these, but they don't work after the DM conversion:

1) The PCI_CLASS value is wrong in HW.

This is worked around in pci_tegra_read_config() by patching up the value
read from that register. Pre-DM, the PCIe core always read this via a
16-bit access to the 16-bit offset 0xa. With DM, 32-bit accesses are used,
so we need to check for offset 0x8 instead. Mask the offset value back to
32-bit alignment to make this work in all cases.

2) Accessing devices other than dev 1 causes a data abort.

Pre-DM, this was worked around in pci_skip_dev(), which the PCIe core code
called during enumeration while iterating over a bus. The DM PCIe core
doesn't use this function. Instead, enhance tegra_pcie_conf_address() to
validate the bdf being accessed, and refuse to access invalid devices.
Since pci_skip_dev() isn't used, delete it.

I've also validated that both these WARs are only needed for Tegra20, by
testing on Tegra30/Cardhu and Tegra124/Jetson TKx. So, compile them in
conditionally.

Fixes: e81ca88451cf ("dm: tegra: pci: Convert tegra boards to driver model for PCI")
Signed-off-by: Stephen Warren <swarren at nvidia.com>
---
 drivers/pci/pci_tegra.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/pci_tegra.c b/drivers/pci/pci_tegra.c
index 5dadf6fa62a7..c5b04daffa65 100644
--- a/drivers/pci/pci_tegra.c
+++ b/drivers/pci/pci_tegra.c
@@ -275,12 +275,17 @@ static int tegra_pcie_conf_address(struct tegra_pcie *pcie, pci_dev_t bdf,
 				return 0;
 			}
 		}
+		return -EFAULT;
 	} else {
+#ifdef CONFIG_TEGRA20
+		unsigned int dev = PCI_DEV(bdf);
+		if (dev != 0)
+			return -EFAULT;
+#endif
+
 		*address = pcie->cs.start + tegra_pcie_conf_offset(bdf, where);
 		return 0;
 	}
-
-	return -EFAULT;
 }
 
 static int pci_tegra_read_config(struct udevice *bus, pci_dev_t bdf,
@@ -299,13 +304,15 @@ static int pci_tegra_read_config(struct udevice *bus, pci_dev_t bdf,
 
 	value = readl(address);
 
+#ifdef CONFIG_TEGRA20
 	/* fixup root port class */
 	if (PCI_BUS(bdf) == 0) {
-		if (offset == PCI_CLASS_REVISION) {
+		if ((offset & ~3) == PCI_CLASS_REVISION) {
 			value &= ~0x00ff0000;
 			value |= PCI_CLASS_BRIDGE_PCI << 16;
 		}
 	}
+#endif
 
 done:
 	*valuep = pci_conv_32_to_size(value, offset, size);
@@ -1041,11 +1048,3 @@ U_BOOT_DRIVER(pci_tegra) = {
 	.probe	= pci_tegra_probe,
 	.priv_auto_alloc_size = sizeof(struct tegra_pcie),
 };
-
-int pci_skip_dev(struct pci_controller *hose, pci_dev_t dev)
-{
-	if (PCI_BUS(dev) != 0 && PCI_DEV(dev) > 0)
-		return 1;
-
-	return 0;
-}
-- 
2.8.1