[PATCH 1/2] POWERPC/fsl-pci: Better ATMU setup

[Kumar Gala]

On Dec 17, 2008, at 1:43 PM, Trent Piepho wrote:

> The code that sets up the outbound ATMU windows, which is used to  
> map CPU
> physical addresses into PCI bus addresses where BARs will be mapped,  
> didn't
> work so well.
>
> For one, it leaked the ioremap() of the ATMU registers.  Another  
> small bug
> was the high 20 bits of the PCI bus address were left as zero.  It's  
> legal
> for prefetchable memory regions to be above 32 bits, so the high 20  
> bits
> might not be zero.
>
> Mainly, it couldn't handle ranges that were not a power of two in  
> size or
> were not naturally aligned.  The ATMU windows have these  
> requirements (size
> & alignment), but the code didn't bother to check if the ranges it was
> programming met them.  If they didn't, the windows would silently be
> programmed incorrectly.
>
> This new code can handle ranges which are not power of two sized nor
> naturally aligned.  It simply splits the ranges into multiple valid  
> ATMU
> windows.  As there are only four windows, pooly aligned or sized  
> ranges
> (which didn't even work before) may run out of windows.  In this  
> case an
> error is printed and an effort is made to disable the unmapped  
> resources.
>
> An improvement that could be made would be to make use of the default
> outbound window.  Iff hose->pci_mem_offset is zero, then it's  
> possible that
> some or all of the ranges might not need an outbound window and  
> could just
> use the default window.
>
> The default ATMU window can support a pci_mem_offset less than zero  
> too,
> but pci_mem_offset is unsigned.  One could say the abilities allowed a
> powerpc pci_controller is neither subset nor a superset of the  
> abilities of
> a Freescale PCIe controller.  Thankfully, the most useful bits are  
> in the
> intersection of the two abilities.
>
> Signed-off-by: Trent Piepho <tpiepho at freescale.com>
> ---
> arch/powerpc/sysdev/fsl_pci.c |  104 +++++++++++++++++++++++++++ 
> +-------------
> 1 files changed, 71 insertions(+), 33 deletions(-)

applied

- k