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ar71xx: work around a PCI controller bug which causes reads to the PCI_COMMAND register to return bogus values - properly fixes ath9k module reload issues

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SVN-Revision: 24236
This commit is contained in:
Felix Fietkau 2010-12-04 01:32:15 +00:00
parent 2a55832f58
commit 8067f3f3cc
2 changed files with 10 additions and 13 deletions
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13
package/mac80211/patches/520-ath9k_pci_error_fix.patch
View file

@ -1,13 +0,0 @@
--- a/drivers/net/wireless/ath/ath9k/pci.c
+++ b/drivers/net/wireless/ath/ath9k/pci.c
@@ -255,6 +255,10 @@ static void ath_pci_remove(struct pci_de
struct ath_wiphy *aphy = hw->priv;
struct ath_softc *sc = aphy->sc;
void __iomem *mem = sc->mem;
+ u16 val;
+
+ /* Do a config read to clear pre-existing pci error status */
+ pci_read_config_word(pdev, PCI_COMMAND, &val);
ath9k_deinit_device(sc);
free_irq(sc->irq, sc);

10
target/linux/ar71xx/files/arch/mips/pci/pci-ar71xx.c
View file

@ -136,6 +136,7 @@ static int ar71xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
static u32 mask[8] = {0, 0xff, 0xffff, 0, 0xffffffff, 0, 0, 0};
unsigned long flags;
u32 data;
int retry = 0;
int ret;
ret = PCIBIOS_SUCCESSFUL;
@ -143,6 +144,7 @@ static int ar71xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
DBG("PCI: read config: %02x:%02x.%01x/%02x:%01d\n", bus->number,
PCI_SLOT(devfn), PCI_FUNC(devfn), where, size);
retry:
spin_lock_irqsave(&ar71xx_pci_lock, flags);
if (bus->number == 0 && devfn == 0) {
@ -176,6 +178,14 @@ static int ar71xx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
*value = (data >> (8 * (where & 3))) & mask[size & 7];
/*
* PCI controller bug: sometimes reads to the PCI_COMMAND register
* return 0xffff, even though the PCI trace shows the correct value.
* Work around this by retrying reads to this register
*/
if (where == PCI_COMMAND && (*value & 0xffff) == 0xffff && retry++ < 2)
goto retry;
return ret;
}