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 <adi@xxxxxxxxxxxx>
arch/mips/pci/pci-bcm1480.c | 8 ++++++++
1 files changed, 8 insertions(+)
Index: lmo/arch/mips/pci/pci-bcm1480.c
===================================================================
--- lmo.orig/arch/mips/pci/pci-bcm1480.c 2005-10-19 22:34:13.000000000 -0700
+++ lmo/arch/mips/pci/pci-bcm1480.c 2005-10-19 22:34:13.000000000 -0700
@@ -232,6 +232,14 @@
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
