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PCI: treat mem BAR type "11" (reserved) as 32-bit, not 64-bit, BAR 

This fixes a minor regression where broken PCI devices that use the
reserved "11" memory BAR type worked before e354597cce but not after.

The low four bits of a memory BAR are "PTT0" where P=1 for prefetchable
BARs, and TT is as follows:

  00  32-bit BAR, anywhere in lower 4GB
  01  anywhere below 1MB (reserved as of PCI 2.2)
  10  64-bit BAR
  11  reserved

Prior to e354597cce, we treated "0100" as a 64-bit BAR and all others,
including prefetchable 64-bit BARs ("1100") as 32-bit BARs.  The e354597cce
fix, which appeared in 2.6.28, treats "x1x0" as 64-bit BARs, so the
reserved "x110" types are treated as 64-bit instead of 32-bit.

This patch returns to treating the reserved "11" type as a 32-bit BAR and
adds a warning if we see it.

It also logs a note if we see a 1M BAR.  This is not a warning, because
such hardware conforms to pre-PCI 2.2 spec, but I think it's worth noting
because Linux ignores the 1M restriction if it ever has to assign the BAR.

CC: Peter Chubb <peterc@gelato.unsw.edu.au>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=35952
Reported-by: Jan Zwiegers <jan@radicalsystems.co.za>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
hifive-unleashed-5.1
Bjorn Helgaas 2011-06-14 13:04:29 -06:00 committed by Jesse Barnes
parent c9b378c7cb
commit 8d6a6a4763
1 changed files with 19 additions and 3 deletions
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22
drivers/pci/probe.c
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@ -100,8 +100,11 @@ static u64 pci_size(u64 base, u64 maxbase, u64 mask)
return size;
}
static inline enum pci_bar_type decode_bar(struct resource *res, u32 bar)
static inline enum pci_bar_type decode_bar(struct pci_dev *dev,
struct resource *res, u32 bar)
{
u32 mem_type;
if ((bar & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
res->flags = bar & ~PCI_BASE_ADDRESS_IO_MASK;
return pci_bar_io;
@ -109,8 +112,21 @@ static inline enum pci_bar_type decode_bar(struct resource *res, u32 bar)
res->flags = bar & ~PCI_BASE_ADDRESS_MEM_MASK;
if (res->flags & PCI_BASE_ADDRESS_MEM_TYPE_64)
mem_type = bar & PCI_BASE_ADDRESS_MEM_TYPE_MASK;
switch (mem_type) {
case PCI_BASE_ADDRESS_MEM_TYPE_32:
break;
case PCI_BASE_ADDRESS_MEM_TYPE_1M:
dev_info(&dev->dev, "1M mem BAR treated as 32-bit BAR\n");
break;
case PCI_BASE_ADDRESS_MEM_TYPE_64:
return pci_bar_mem64;
default:
dev_warn(&dev->dev,
"mem unknown type %x treated as 32-bit BAR\n",
mem_type);
break;
}
return pci_bar_mem32;
}
@ -164,7 +180,7 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
l = 0;
if (type == pci_bar_unknown) {
type = decode_bar(res, l);
type = decode_bar(dev, res, l);
res->flags |= pci_calc_resource_flags(l) | IORESOURCE_SIZEALIGN;
if (type == pci_bar_io) {
l &= PCI_BASE_ADDRESS_IO_MASK;