From 87fe054b87484f055ead8916fe64cbf806f10507 Mon Sep 17 00:00:00 2001 From: nbd Date: Sat, 4 Dec 2010 10:31:18 +0000 Subject: [PATCH] ar71xx: merge pci register read workaround from r24236 git-svn-id: svn://svn.openwrt.org/openwrt/branches/backfire@24240 3c298f89-4303-0410-b956-a3cf2f4a3e73 --- target/linux/ar71xx/files/arch/mips/pci/pci-ar71xx.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/target/linux/ar71xx/files/arch/mips/pci/pci-ar71xx.c b/target/linux/ar71xx/files/arch/mips/pci/pci-ar71xx.c index 7d0eee9db..a75b9ab68 100644 --- a/target/linux/ar71xx/files/arch/mips/pci/pci-ar71xx.c +++ b/target/linux/ar71xx/files/arch/mips/pci/pci-ar71xx.c @@ -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; } -- 2.35.1