From 32136568a9828c27c07eedb8d2b3e3d9fe8d87ba Mon Sep 17 00:00:00 2001 From: Alexander Bigga Date: Tue, 29 Aug 2006 16:48:34 +0200 Subject: [PATCH] [MIPS] Fix for pci config_access on alchemy au1x000 I've encountered a serious problem with PCI config space access on Au1x000 platforms with recent 2.6.x-kernel. With 2.4.31 the same hardware works fine. So I was looking for the differences: Symptoms: - no PCI-device is seen on bootup though two or three cards are present - lspci output is empty - OR: lspci shows 20 times the same device (- OR: in some slot-configurations it worked anyhow) System(s): 1. platform with Au1500 and three PCI-devices (actually a mycable XXS1500 with backplane for three PCI-devices) 2. platform with Au1550 and two PCI-devices (custom board) Debugging: I digged down to the config_access() of the au1xxx-processors in arch/mips/pci/ops-au1000.c and switched on DEBUG. The code of config_access() seems to be almost the same as of the 2.4.x-kernel. But the "pci_cfg_vm->addr" returned by get_vm_area(0x2000, 0) once on booting is different. That's of course not forbidden. But the alignment seems to be wrong. In my case, I received: 2.4.31: pci_cfg_vm->addr = c0000000 2.6.18-rc5: pci_cfg_vm->addr = c0101000 To make it short: With 2.6.x it fails on the first config-access with: "PCI ERR detected: status 83a00356". Fixup: My fix is now, to use the VM_IOREMAP-flag in the get_vm_area call. This flag seems to be introduced in mm/vmalloc.c a long time ago (in 2.6.7-bk13, I found in gitweb). Now, the returned address is pci_cfg_vm->addr = c0104000 and everything works fine. Signed-off-by: Ralf Baechle --- arch/mips/pci/ops-au1000.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/pci/ops-au1000.c b/arch/mips/pci/ops-au1000.c index 0c0c1e6519f..8ae46481fcb 100644 --- a/arch/mips/pci/ops-au1000.c +++ b/arch/mips/pci/ops-au1000.c @@ -110,7 +110,7 @@ static int config_access(unsigned char access_type, struct pci_bus *bus, if (first_cfg) { /* reserve a wired entry for pci config accesses */ first_cfg = 0; - pci_cfg_vm = get_vm_area(0x2000, 0); + pci_cfg_vm = get_vm_area(0x2000, VM_IOREMAP); if (!pci_cfg_vm) panic (KERN_ERR "PCI unable to get vm area\n"); pci_cfg_wired_entry = read_c0_wired(); -- 2.41.1