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: NAndy Isaacson <adi@broadcom.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

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