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authorAlexander Bigga <ab@mycable.de>2006-08-29 10:48:34 -0400
committerRalf Baechle <ralf@linux-mips.org>2006-09-27 08:37:38 -0400
commit32136568a9828c27c07eedb8d2b3e3d9fe8d87ba (patch)
tree97b07246b93d46b9ad9bcc654a1178077d503053 /arch/mips
parent898d229107f7aa8ea45685c11e2930783755f9ba (diff)
[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 <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/pci/ops-au1000.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/mips/pci/ops-au1000.c b/arch/mips/pci/ops-au1000.c
index 0c0c1e6519f9..8ae46481fcb7 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,
110 if (first_cfg) { 110 if (first_cfg) {
111 /* reserve a wired entry for pci config accesses */ 111 /* reserve a wired entry for pci config accesses */
112 first_cfg = 0; 112 first_cfg = 0;
113 pci_cfg_vm = get_vm_area(0x2000, 0); 113 pci_cfg_vm = get_vm_area(0x2000, VM_IOREMAP);
114 if (!pci_cfg_vm) 114 if (!pci_cfg_vm)
115 panic (KERN_ERR "PCI unable to get vm area\n"); 115 panic (KERN_ERR "PCI unable to get vm area\n");
116 pci_cfg_wired_entry = read_c0_wired(); 116 pci_cfg_wired_entry = read_c0_wired();