On 2012-10-30 08:01, Ian Abbott wrote:
On 30/10/12 03:13, Bjorn Helgaas wrote:
On Mon, Oct 29, 2012 at 8:40 AM, Ian Abbott <abbotti@xxxxxxxxx> wrote:
The PLX PCI 9050 PCI Target bridge controller has a bug that prevents
its local configuration registers being read through BAR0 (memory) or
BAR1 (i/o) if the base address lies on an odd 128-byte boundary, i.e. if
bit 7 of the base address is non-zero. This bug is described in the PCI
9050 errata list, version 1.4, May 2005. It was fixed in the
pin-compatible PCI 9052, which can be distinguished from the PCI 9050 by
checking the revision in the PCI header, which is hard-coded for these
chips.
Workaround the problem by re-allocating the affected regions to a
256-byte boundary. Note that BAR0 and/or BAR1 may have been disabled
(size 0) during initialization of the PCI chip when its configuration is
read from a serial EEPROM.
Currently, the fix-up has only been used for devices with the default
vendor and device ID of the PLX PCI 9050. The PCI 9052 shares the same
default device ID as the PCI 9050 but they have different PCI revision
codes.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/pci/quirks.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 7a451ff..7e6be56 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1790,6 +1790,31 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_TOSHIBA_2,
PCI_DEVICE_ID_TOSHIBA_TC86C001_IDE,
quirk_tc86c001_ide);
+/*
+ * PLX PCI 9050 PCI Target bridge controller has an errata that prevents the
+ * local configuration registers accessible via BAR0 (memory) or BAR1 (i/o)
+ * being read correctly if bit 7 of the base address is set.
+ * The BAR0 or BAR1 region may be disabled (size 0) or enabled (size 128).
+ * Re-allocate the regions to a 256-byte boundary if necessary.
+ */
+static void __devinit quirk_plx_pci9050(struct pci_dev *dev)
+{
+ unsigned int bar;
+
+ /* Fixed in revision 2 (PCI 9052). */
+ if (dev->revision >= 2)
+ return;
+ for (bar = 0; bar <= 1; bar++)
+ if (pci_resource_len(dev, bar) == 0x80 &&
+ (pci_resource_start(dev, bar) & 0x80)) {
+ struct resource *r = &dev->resource[bar];
+ r->start = 0;
+ r->end = 0xff;
I assume the intent here is to make these BARs "unassigned" so they
will be reassigned later? We don't yet have a clean generic way of
indicating "unassigned," so "r->start = 0" is the best we can do for
now.
I more-or-less copied the method from quirk_tc86c001_ide(). I don't
have any prior experience with writing PCI quirks, so I don't know if
this is the best way to do it! All I really care about is that these
BARs don't have bit 7 set.
I think it'd be nice to have a dev_info() here to explain what's going
on. Otherwise, the dmesg will be a bit mysterious.
OK, I'll add that in the next version of this patch.
I've added a dev_info() on my local system that I'll submit in version 2
of the patch later but first I thought I'd show the dmesg output I get
with this patch:
pci 0000:01:08.0: [14dc:0004] type 00 class 0x068000
pci 0000:01:08.0: reg 14: [io 0xd400-0xd47f]
pci 0000:01:08.0: reg 18: [io 0xd000-0xd007]
pci 0000:01:08.0: reg 1c: [io 0xcc00-0xcc07]
pci 0000:01:08.0: Re-allocating PLX PCI 9050 BAR 1 to avoid 0x80
boundary bug
That last message is the one I added locally. The vendor and device ID
in the first message is different than the ones I'm applying in these
patches; it's just a local change. You may also notice that BAR 1 (reg
14) doesn't have bit 7 set to 1, so I had to temporarily disable that
check in the code to test the re-allocation mechanism. This particular
device has BAR 0 (reg 10) disabled (size 0) but it would normally be a
memory region of size 128.
Resetting the region's start address to 0 had some knock on effects that
I'm a bit concerned about:
...
pnp 00:02: [io 0x0010-0x001f]
pnp 00:02: [io 0x0022-0x003f]
pnp 00:02: [io 0x0044-0x005f]
pnp 00:02: [io 0x0062-0x0063]
pnp 00:02: [io 0x0065-0x006f]
pnp 00:02: [io 0x0074-0x007f]
pnp 00:02: [io 0x0091-0x0093]
pnp 00:02: [io 0x00a2-0x00bf]
pnp 00:02: [io 0x00e0-0x00ef]
pnp 00:02: [io 0x04d0-0x04d1]
pnp 00:02: [io 0x0800-0x087f]
pnp 00:02: [io 0x0290-0x0297]
pnp 00:02: disabling [io 0x0010-0x001f] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x0022-0x003f] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x0044-0x005f] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x0062-0x0063] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x0065-0x006f] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x0074-0x007f] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x0091-0x0093] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x00a2-0x00bf] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
pnp 00:02: disabling [io 0x00e0-0x00ef] because it overlaps
0000:01:08.0 BAR 1 [io 0x0000-0x00ff]
system 00:02: [io 0x04d0-0x04d1] has been reserved
system 00:02: [io 0x0800-0x087f] has been reserved
system 00:02: [io 0x0290-0x0297] has been reserved
system 00:02: Plug and Play ACPI device, IDs PNP0c02 (active)
Eventually, BAR 1 of the PCI device gets re-assigned:
...
pci 0000:01:08.0: BAR 1: assigned [io 0xc000-0xc0ff]
--
-=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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