* Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx> wrote:
> diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
> index 5ead808..6e3f22c 100644
> --- a/arch/x86/pci/i386.c
> +++ b/arch/x86/pci/i386.c
> @@ -78,6 +78,47 @@ pcibios_align_resource(void *data, struct resource *res,
> }
> EXPORT_SYMBOL(pcibios_align_resource);
>
> +static struct resource mem64 = {
> + .name = "PCI mem64",
> + .start = (resource_size_t)(1 << 16) << 16, /* 4Gb */
> + .end = -1,
> + .flags = IORESOURCE_MEM,
> +};
> +
> +static void pcibios_pci64_setup(void)
> +{
> + struct resource *r64 = &mem64, *root = &iomem_resource;
> + struct pci_bus *b;
> +
> + if (!r64->start)
> + return; /* 32-bit phys. address, nothing to do */
> +
> + if (insert_resource(root, r64)) {
> + printk(KERN_WARNING "PCI: Failed to allocate PCI64 space\n");
> + return;
> + }
> +
> + list_for_each_entry(b, &pci_root_buses, node) {
> + /* Is this a "standard" root bus created by pci_create_bus? */
> + if (b->resource[1] != root || b->resource[2])
> + continue;
> + b->resource[2] = r64; /* create DAC resource */
> + }
> +}
> +
> +static void pcibios_pci64_verify(void)
> +{
> + struct pci_bus *b;
> +
> + if (mem64.flags & IORESOURCE_MEM64)
> + return; /* presumably DAC works */
> + list_for_each_entry(b, &pci_root_buses, node) {
> + if (b->resource[2] == &mem64)
> + b->resource[2] = NULL;
> + }
> + printk(KERN_INFO "PCI: allocations above 4G disabled\n");
> +}
The principle of probing + tearing down the mem64 resource if no
bridge is 64-bit looks worth trying, but i'd suggest a different
code structure to better handle true 32-bit systems built with
32-bit resource_size_t:
- move this new code into a new file, arch/x86/pci/dac_64bit.c
- build this file only if CONFIG_PHYS_ADDR_T_64BIT is set
- add inline functions for pcibios_pci64_setup() and
pcibios_pci64_verify() in the !CONFIG_PHYS_ADDR_T_64BIT case.
That way this code wont be built into the kernel on true 32-bit
systems. This check can then go away as well.
> + if (!r64->start)
> + return; /* 32-bit phys. address, nothing to do */
Furthermore, the filenames are very confusing in the
arch/x86/pci/ directory and should be cleaned up ASAP. At
minimum we should do:
git mv arch/x86/pci/pcbios.c arch/x86/pci/bios_32.c
git mv arch/x86/pci/i386.c arch/x86/pci/bios.c
(and fix up the Makefile.) There's nothing 32-bit about
"i386.c", the 64-bit x86 platform code uses it too!
Also, this one:
> + if (insert_resource(root, r64)) {
> + printk(KERN_WARNING "PCI: Failed to allocate PCI64 space\n");
> + return;
> + }
Should be a more prominent WARN(), not a printk. We can only hit
this path if the x86 platform and the PCI probing code is buggy,
and we want to fix such bugs.
Thanks,
Ingo
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