[RFC PATCH 2/5] soc/fsl/qbman: Use shared-dma-pool for QMan private memory allocations

[Robin Murphy]

On 31/03/17 04:27, Michael Ellerman wrote:
> Robin Murphy <robin.murphy at arm.com> writes:
> 
>> Hi Roy,
>>
>> On 29/03/17 22:13, Roy Pledge wrote:
>>> Use the shared-memory-pool mechanism for frame queue descriptor and
>>> packed frame descriptor record area allocations.
>>
>> Thanks for persevering with this - in my opinion it's now looking like
>> it was worth the effort :)
>>
>> AFAICS the ioremap_wc() that this leads to does appear to give back
>> something non-cacheable on PPC (assuming "pgprot_noncached_wc" isn't
>> horrendously misnamed), and "no-map" should rule out any cacheable
>> linear map alias existing, so it would seem that this approach should
>> avert Scott's concerns about attribute mismatches.
> 
> How does 'no-map' translate into something being excluded from the
> linear mapping?

Reserved regions marked with "no-map" get memblock_remove()d by
early_init_dt_alloc_reserved_memory_arch(). As I understand things, the
linear map should only cover memblock areas, and it would be explicitly
violating the semantics of "no-map" to still cover such a region.

Robin.

> 
> cheers
>