[XenPPC] Warning: fix RTC/NVRAM accesses on Maple

[Jimi Xenidis <jimix@xxxxxxxxxxxxxx>]

Hollis discovered that Linux could not find the ISA bus.  It turns  
out the PIBS ISA information is incorrect, making finding ISA devices  
in a "documented" way impossible.  We are patching linux, I'll be  
adding a similar work-around on Xen so you can find the UART :)
Hollis's Linux diff is below.
-JX

Begin forwarded message:

> From: Hollis Blanchard <hollisb@xxxxxxxxxx>
> Date: May 18, 2006 5:34:00 PM EDT
> To: linuxppc-dev@xxxxxxxxxx
> Cc: Ben Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>, Jimi Xenidis  
> <jimix@xxxxxxxxxxxxxx>
> Subject: [patch] fix RTC/NVRAM accesses on Maple
>
> It looks like RTC and NVRAM accesses (including halt/reboot) on Maple
> have been broken since January, when an untested build fix went in
> ("[PATCH] powerpc: Fix Maple build").
>
> PIBS (the firmware on Maple) has a bad "ranges" property for the ISA
> bus, which means of_address_to_resource() fails for ISA devices, and
> that breaks maple_find_nvram_base() and maple_get_boot_time().
>
> This patch adds ifdefs mid-file, but some were already present  
> anyways,
> and I don't see a better way.
>
> Please apply.
>
> --
> Hollis Blanchard
> IBM Linux Technology Center
>
> Signed-off-by: Hollis Blanchard <hollisb@xxxxxxxxxx>
>
> diff -r 5158eb8d85b7 arch/powerpc/kernel/prom_init.c
> --- a/arch/powerpc/kernel/prom_init.c   Thu May 18 11:32:22 2006 +0700
> +++ b/arch/powerpc/kernel/prom_init.c   Thu May 18 16:23:40 2006 -0500
> @@ -2057,10 +2057,44 @@ static void __init flatten_device_tree(v
>
>  }
>
> -
> -static void __init fixup_device_tree(void)
> -{
> +#ifdef CONFIG_PPC_MAPLE
> +/* PIBS Version 1.05.0000 04/26/2005 has an incorrect /ht/isa/ 
> ranges property.
> + * The values are bad, and it doesn't even have the right number  
> of cells. */
> +static void __init fixup_device_tree_maple(void)
> +{
> +       phandle isa;
> +       u32 isa_ranges[6];
> +
> +       isa = call_prom("finddevice", 1, 1, ADDR("/ht@0/isa@4"));
> +       if (!PHANDLE_VALID(isa))
> +               return;
> +
> +       if (prom_getprop(isa, "ranges", isa_ranges, sizeof(isa_ranges))
> +           == PROM_ERROR)
> +               return;
> +
> +       if (isa_ranges[0] != 0x1 ||
> +           isa_ranges[1] != 0xf4000000 ||
> +           isa_ranges[2] != 0x00010000)
> +               return;
> +
> +       prom_printf("fixing up bogus ISA range on Maple...\n");
> +
> +       isa_ranges[0] = 0x1;
> +       isa_ranges[1] = 0x0;
> +       isa_ranges[2] = 0x0;
> +       isa_ranges[3] = 0x0;
> +       isa_ranges[4] = 0x0;
> +       isa_ranges[5] = 0x00010000;
> +       prom_setprop(isa, "/ht@0/isa@4", "ranges",
> +                    isa_ranges, sizeof(isa_ranges));
> +}
> +#endif
> +
> +               
>  #if defined(CONFIG_PPC64) && defined(CONFIG_PPC_PMAC)
> +static void __init fixup_device_tree_pmac(void)
> +{
>         phandle u3, i2c, mpic;
>         u32 u3_rev;
>         u32 interrupts[2];
> @@ -2097,9 +2131,18 @@ static void __init fixup_device_tree(voi
>         parent = (u32)mpic;
>         prom_setprop(i2c, "/u3@0,f8000000/i2c@f8001000", "interrupt-parent",
>                      &parent, sizeof(parent));
> -#endif
> -}
> -
> +}
> +#endif
> +
> +static void __init fixup_device_tree(void)
> +{
> +#ifdef CONFIG_PPC_MAPLE
> +       fixup_device_tree_maple();
> +#endif
> +#if defined(CONFIG_PPC64) && defined(CONFIG_PPC_PMAC)
> +       fixup_device_tree_pmac();
> +#endif
> +}
>
>  static void __init prom_find_boot_cpu(void)
>  {
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