From: Andrew Isaacson Date: Thu, 20 Oct 2005 06:59:46 +0000 (-0700) Subject: pci-expmem-hack X-Git-Tag: v2.6.15-rc1~731^2~1^2~10 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cb4262481fce1d43ac9a483be4faf36fdd1c7abb;p=linux-2.6 pci-expmem-hack CFE 1.2.5 and earlier fails to turn on the ExpMemEn bit in the PCIFeatureControl register, which means that DMA does not work beyond physical address 01_0000_0000, ergo to DRAM beyond 1GB. With ExpMemEn turned on, 01_0000_0000-0f_ffff_ffff is mapped, so DMA works for up to 61 GB of DRAM. Will be fixed in CFE 1.2.6 (yet to be released). Signed-Off-By: Andy Isaacson Signed-off-by: Ralf Baechle --- diff --git a/arch/mips/pci/pci-bcm1480.c b/arch/mips/pci/pci-bcm1480.c index 4905d8593d..f194b4e4f8 100644 --- a/arch/mips/pci/pci-bcm1480.c +++ b/arch/mips/pci/pci-bcm1480.c @@ -232,6 +232,14 @@ static int __init bcm1480_pcibios_init(void) bcm1480_bus_status |= PCI_BUS_ENABLED; } + /* turn on ExpMemEn */ + cmdreg = READCFG32(CFGOFFSET(0, PCI_DEVFN(PCI_BRIDGE_DEVICE, 0), 0x40)); + printk("PCIFeatureCtrl = %x\n", cmdreg); + WRITECFG32(CFGOFFSET(0, PCI_DEVFN(PCI_BRIDGE_DEVICE, 0), 0x40), + cmdreg | 0x10); + cmdreg = READCFG32(CFGOFFSET(0, PCI_DEVFN(PCI_BRIDGE_DEVICE, 0), 0x40)); + printk("PCIFeatureCtrl = %x\n", cmdreg); + /* * Establish mappings in KSEG2 (kernel virtual) to PCI I/O * space. Use "match bytes" policy to make everything look