On Wednesday 30 May 2012, Rob Herring wrote:

On 05/30/2012 01:02 PM, Richard Maw wrote:

quoted

We've tried to track down the problem, but we couldn't get much further
than finding out that the IO_SPACE_LIMIT in kernel/resource.c is 0xffff,
which is lower than the required 0x44000000.

We're not sure whether this is a problem with it not being allocated
enough space, or that it is not being translated properly.

Is this a known issue, I did a quick google for the "sym53c8xx
 can't reserve io" error, but nothing turned up.
If not, does anyone have any pointers to how this could be fixed?

I believe this is the same issue:

http://www.gossamer-threads.com/lists/linux/kernel/1543569

In looking at various PCI platforms and for a qemu platform with PCI to
test PCI changes, I had concluded (wrongly I guess) that Versatile PCI
was broken. This patch which has never gone upstream also played a part
in my conclusion:

http://lists.infradead.org/pipermail/linux-arm-kernel/2010-July/021035.html

The simple fix is to restore io.h for Versatile, but I'm looking for a
better way.

It looks like it's a simple bug in pci.c, which puts the wrong thing into the
pcibios_min_io variable.

Does the below patch fix it?

	Arnd

diff --git a/arch/arm/mach-versatile/pci.c b/arch/arm/mach-versatile/pci.c
index 4ae4fc8..aeb7b60 100644
--- a/arch/arm/mach-versatile/pci.c
+++ b/arch/arm/mach-versatile/pci.c

@@ -305,7 +305,7 @@ int __init pci_versatile_setup(int nr, struct pci_sys_data *sys)
 
 void __init pci_versatile_preinit(void)
 {
-	pcibios_min_io = 0x44000000;
+	pcibios_min_io = 0x100;
 	pcibios_min_mem = 0x50000000;
 
 	__raw_writel(VERSATILE_PCI_MEM_BASE0 >> 28, PCI_IMAP0);