Re: [PATCH] mmc: sdhci-xenon: Fix 2G limitation on AC5 SoC

[Christoph Hellwig]

On Thu, Aug 18, 2022 at 03:07:40PM +0300, Vadym Kochan wrote:
> It works with the following changes:
> 
>     #1 dma-ranges = <0x0 0x0 0x2 0x0 0x0 0x80000000>;
> 
>     #3 swiotlb="force"
> 
> Is it OK to force the memory allocation from the start for the swiotlb ?

It should be ok, but isn't really optimal.

I wonder if we should just allow DT to specify the swiotlb buffer
location.  Basically have yet another RESERVEDMEM_OF_DECLARE variant
for it, which shouldn't be all that much work except for figuring
out the interaction with the various kernel command line options.