From a758de0e272db9960c814bb031164b12e660e99c Mon Sep 17 00:00:00 2001 From: Myron Stowe Date: Tue, 3 Feb 2015 16:01:24 -0700 Subject: [PATCH] PCI: Handle read-only BARs on AMD CS553x devices commit 06cf35f903aa6da0cc8d9f81e9bcd1f7e1b534bb upstream. Some AMD CS553x devices have read-only BARs because of a firmware or hardware defect. There's a workaround in quirk_cs5536_vsa(), but it no longer works after 36e8164882ca ("PCI: Restore detection of read-only BARs"). Prior to 36e8164882ca, we filled in res->start; afterwards we leave it zeroed out. The quirk only updated the size, so the driver tried to use a region starting at zero, which didn't work. Expand quirk_cs5536_vsa() to read the base addresses from the BARs and hard-code the sizes. On Nix's system BAR 2's read-only value is 0x6200. Prior to 36e8164882ca, we interpret that as a 512-byte BAR based on the lowest-order bit set. Per datasheet sec 5.6.1, that BAR (MFGPT) requires only 64 bytes; use that to avoid clearing any address bits if a platform uses only 64-byte alignment. [bhelgaas: changelog, reduce BAR 2 size to 64] Fixes: 36e8164882ca ("PCI: Restore detection of read-only BARs") Link: https://bugzilla.kernel.org/show_bug.cgi?id=85991#c4 Link: http://support.amd.com/TechDocs/31506_cs5535_databook.pdf Link: http://support.amd.com/TechDocs/33238G_cs5536_db.pdf Reported-and-tested-by: Nix Signed-off-by: Myron Stowe Signed-off-by: Bjorn Helgaas [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- drivers/pci/quirks.c | 41 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 37 insertions(+), 4 deletions(-) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index 9b48d615a6ab..127dfe5d67e1 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -388,19 +388,52 @@ static void __devinit quirk_s3_64M(struct pci_dev *dev) DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_S3, PCI_DEVICE_ID_S3_868, quirk_s3_64M); DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_S3, PCI_DEVICE_ID_S3_968, quirk_s3_64M); +static void quirk_io(struct pci_dev *dev, int pos, unsigned size, + const char *name) +{ + u32 region; + struct pci_bus_region bus_region; + struct resource *res = dev->resource + pos; + + pci_read_config_dword(dev, PCI_BASE_ADDRESS_0 + (pos << 2), ®ion); + + if (!region) + return; + + res->name = pci_name(dev); + res->flags = region & ~PCI_BASE_ADDRESS_IO_MASK; + res->flags |= + (IORESOURCE_IO | IORESOURCE_PCI_FIXED | IORESOURCE_SIZEALIGN); + region &= ~(size - 1); + + /* Convert from PCI bus to resource space */ + bus_region.start = region; + bus_region.end = region + size - 1; + pcibios_bus_to_resource(dev->bus, res, &bus_region); + + dev_info(&dev->dev, FW_BUG "%s quirk: reg 0x%x: %pR\n", + name, PCI_BASE_ADDRESS_0 + (pos << 2), res); +} + /* * Some CS5536 BIOSes (for example, the Soekris NET5501 board w/ comBIOS * ver. 1.33 20070103) don't set the correct ISA PCI region header info. * BAR0 should be 8 bytes; instead, it may be set to something like 8k * (which conflicts w/ BAR1's memory range). + * + * CS553x's ISA PCI BARs may also be read-only (ref: + * https://bugzilla.kernel.org/show_bug.cgi?id=85991 - Comment #4 forward). */ static void __devinit quirk_cs5536_vsa(struct pci_dev *dev) { + static char *name = "CS5536 ISA bridge"; + if (pci_resource_len(dev, 0) != 8) { - struct resource *res = &dev->resource[0]; - res->end = res->start + 8 - 1; - dev_info(&dev->dev, "CS5536 ISA bridge bug detected " - "(incorrect header); workaround applied.\n"); + quirk_io(dev, 0, 8, name); /* SMB */ + quirk_io(dev, 1, 256, name); /* GPIO */ + quirk_io(dev, 2, 64, name); /* MFGPT */ + dev_info(&dev->dev, "%s bug detected (incorrect header); workaround applied\n", + name); } } DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CS5536_ISA, quirk_cs5536_vsa); -- 2.39.2