[PATCH 3.10 307/319] PCI: Handle read-only BARs on AMD CS553x devices

Willy Tarreau
2017-02-05T19:37:55Z

From: Myron Stowe <myron.stowe@redhat.com>

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.

[js] pcibios_bus_to_resource takes pdev, not bus in 3.12

[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 <nix@esperi.org.uk>
Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
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 a663715..b6625e5 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -339,19 +339,52 @@ static void 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), &region);
+
+ 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, 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 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);
--
2.8.0.rc2.1.gbe9624a