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[PATCH] fix PCI-memory access on Alchemy Au15x0

Subject: [PATCH] fix PCI-memory access on Alchemy Au15x0
From: Alexander Bigga <>
Date: Thu, 21 Dec 2006 11:25:19 +0100
Original-recipient: rfc822;
User-agent: Mutt/1.5.9i

the PCI support on Alchemy Au1500 and Au1550 based platforms is actually broken 
the current mips-kernel.

The problem was introduced in with the casting of some 36bit-defines
(PCI memory) in au1000.h to resource_size_t which may be u32 or u64 depending on
the experimental CONFIG_RESOURCES_64BIT.

With unset CONFIG_RESOURCES_64BIT, the pci-memory cannot be accessed because
the ioremap in arch/mips/au1000/common/pci.c already used the truncated
With set CONFIG_RESOURCES_64BIT, things get even worse, because PCI-scan
aborts, due to resource conflict: request_resource() in arch/mips/pci/pci.c
fails because the maximum iomem-address is 0xffffffff (32bit) but the
pci-memory-start-address is 0x440000000 (36bit).

To get pci working again, I propose the following patch:

1. remove the resource_size_t-casting from au1000.h again
2. make the casting in arch/mips/au1000/common/pci.c (it's allowed and
necessary here. The 36bit-handling will be done in __fixup_bigphys_addr).

With this patch pci works again like in, the gcc-compile warnings
in pci.c are gone and it doesn't depend on CONFIG_EXPERIMENTAL.

Only advantages ;-) Nevertheless, I'm open for your comments or even better

Best regards,


Signed-off-by: Alexander Bigga <>

 arch/mips/au1000/common/pci.c         |    8 ++++----
 include/asm-mips/mach-au1x00/au1000.h |   12 ++++++------
 2 files changed, 10 insertions(+), 10 deletions(-)

--- linux-        2006-12-12 
00:38:26.000000000 +0100
+++ linux-    2006-12-21 
09:58:15.000000000 +0100
@@ -1665,12 +1665,12 @@
  * addresses.  For PCI IO, it's simpler because we get to do the ioremap
  * ourselves and then adjust the device's resources.
-#define Au1500_EXT_CFG            ((resource_size_t) 0x600000000ULL)
-#define Au1500_EXT_CFG_TYPE1      ((resource_size_t) 0x680000000ULL)
-#define Au1500_PCI_IO_START       ((resource_size_t) 0x500000000ULL)
-#define Au1500_PCI_IO_END         ((resource_size_t) 0x5000FFFFFULL)
-#define Au1500_PCI_MEM_START      ((resource_size_t) 0x440000000ULL)
-#define Au1500_PCI_MEM_END        ((resource_size_t) 0x44FFFFFFFULL)
+#define Au1500_EXT_CFG            0x600000000ULL
+#define Au1500_EXT_CFG_TYPE1      0x680000000ULL
+#define Au1500_PCI_IO_START       0x500000000ULL
+#define Au1500_PCI_IO_END         0x5000FFFFFULL
+#define Au1500_PCI_MEM_START      0x440000000ULL
+#define Au1500_PCI_MEM_END        0x44FFFFFFFULL
 #define PCI_IO_START    (Au1500_PCI_IO_START + 0x1000)
 #define PCI_IO_END      (Au1500_PCI_IO_END)
--- linux-       2006-12-12 
00:38:26.000000000 +0100
+++ linux-    2006-12-20 
20:22:55.000000000 +0100
@@ -39,15 +39,15 @@
 /* TBD */
 static struct resource pci_io_resource = {
-       .start  = PCI_IO_START,
-       .end    = PCI_IO_END,
+       .start  = (resource_size_t)PCI_IO_START,
+       .end    = (resource_size_t)PCI_IO_END,
        .name   = "PCI IO space",
        .flags  = IORESOURCE_IO
 static struct resource pci_mem_resource = {
-       .start  = PCI_MEM_START,
-       .end    = PCI_MEM_END,
+       .start  = (resource_size_t)PCI_MEM_START,
+       .end    = (resource_size_t)PCI_MEM_END,
        .name   = "PCI memory space",
        .flags  = IORESOURCE_MEM

Alexander Bigga      Tel: +49-4321-55956-25
mycable GmbH         Fax: +49-4321-55956-10
Gartenstrasse 10    
D-24534 Neumuenster  eMail:

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