Re: [PATCH v2 1/4] pci: program correct bridge limit registers during probe

[Thomas Huth <thuth@redhat.com>]

On Mon, 27 Apr 2015 13:32:30 +0530
Nikunj A Dadhania <nikunj@linux.vnet.ibm.com> wrote:

> According to the pci-to-pci bridge specification, memory/io limit
> should be the last address of the window, while currently its set to
> last + 1. It broke when the memory range was increased and hit 32-bit
> limit. The last address in the window is 0xFFFF.FFFF and max-mmio is
> 0x1.0000.0000, because of the bug 0x0000 got programmed in the memory
> limit register. All the mmio reads across the pci-to-pci bridge
> started failing during probe.
> 
> All pci-bridge-set-[mmio,mem,io]-base sufferred from similar problem.
> 
> Suggested-by: Thomas Huth <thuth@redhat.com>
> Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
> ---
>  slof/fs/pci-scan.fs | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/slof/fs/pci-scan.fs b/slof/fs/pci-scan.fs
> index 15d0c8e..b8b9fe6 100644
> --- a/slof/fs/pci-scan.fs
> +++ b/slof/fs/pci-scan.fs
> @@ -87,7 +87,7 @@ here 100 allot CONSTANT pci-device-vec
>          pci-next-mmio @ 100000 #aligned         \ read the current Value and align to 1MB boundary
>          dup 100000 + pci-next-mmio !            \ and write back with 1MB for bridge
>          10 rshift                               \ mmio-base reg is only the upper 16 bits
> -        pci-max-mmio @ FFFF0000 and or          \ and Insert mmio Limit (set it to max)
> +        pci-max-mmio @ 1- FFFF0000 and or       \ and Insert mmio Limit (set it to max)
>          swap 20 + rtas-config-l!                \ and write it into the bridge
>  ;
>  
> @@ -116,7 +116,7 @@ here 100 allot CONSTANT pci-device-vec
>                  2 pick 2C + rtas-config-l!      \ | and set the Limit
>          THEN                                    \ FI
>          10 rshift                               \ keep upper 16 bits
> -        pci-max-mem @ FFFF0000 and or           \ and Insert mmem Limit (set it to max)
> +        pci-max-mem @ 1- FFFF0000 and or        \ and Insert mmem Limit (set it to max)
>          swap 24 + rtas-config-l!                \ and write it into the bridge
>  ;
>  
> @@ -150,7 +150,7 @@ here 100 allot CONSTANT pci-device-vec
>                  swap 30 + rtas-config-l!        \ | and write it into the Base-Upper16-bits
>          THEN                                    \ FI
>          8 rshift 000000FF and                   \ keep upper 8 bits
> -        pci-max-io @ 0000FF00 and or            \ insert upper 8 bits of Max-Limit
> +        pci-max-io @ 1- 0000FF00 and or         \ insert upper 8 bits of Max-Limit
>          over rtas-config-l@ FFFF0000 and        \ fetch original Value
>          or swap 1C + rtas-config-l!             \ and write it into the bridge
>  ;

Reviewed-by: Thomas Huth <thuth@redhat.com>