[PATCH] PCI: fix MMIO addressing collisions

From: Patrick Jefferson
Date: Tue May 23 2006 - 13:25:46 EST


Clearing PCI Command bits fixes machine halts observed during sizing seqences using MMIO cycles. Clearing the bits is suggested by an implementation note in the PCI spec.


Signed-off-by: Patrick Jefferson <patrick.jefferson@xxxxxx>

--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -147,7 +147,7 @@ static u32 pci_size(u32 base, u32 maxbas
static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
unsigned int pos, reg, next;
- u32 l, sz;
+ u32 l, sz, cmd;
struct resource *res;

for(pos=0; pos<howmany; pos = next) {
@@ -155,10 +155,14 @@ static void pci_read_bases(struct pci_de
res = &dev->resource[pos];
res->name = pci_name(dev);
reg = PCI_BASE_ADDRESS_0 + (pos << 2);
+ /* disable Memory & I/O decoders before sizing a BAR */
+ pci_read_config_dword(dev, PCI_COMMAND, &cmd);
+ pci_write_config_dword(dev, PCI_COMMAND, cmd & ~(PCI_COMMAND_IO|PCI_COMMAND_MEMORY));
pci_read_config_dword(dev, reg, &l);
pci_write_config_dword(dev, reg, ~0);
pci_read_config_dword(dev, reg, &sz);
pci_write_config_dword(dev, reg, l);
+ pci_write_config_dword(dev, PCI_COMMAND, cmd);
if (!sz || sz == 0xffffffff)
if (l == 0xffffffff)

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