On Tue, Apr 22, 2014 at 9:52 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Friday 18 April 2014, Ley Foon Tan wrote:
>
>> +static inline int dma_supported(struct device *dev, u64 mask)
>> +{
>> + /* we fall back to GFP_DMA when the mask isn't all 1s,
>> + * so we can't guarantee allocations that must be
>> + * within a tighter range than GFP_DMA.
>> + */
>> + if (mask < 0x00ffffff)
>> + return 0;
>> +
>> + return 1;
>> +}
>
>> +void *dma_alloc_coherent(struct device *dev, size_t size,
>> + dma_addr_t *dma_handle, gfp_t gfp)
>> +{
>> + void *ret;
>> +
>> + /* ignore region specifiers */
>> + gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
>> +
>> + /* optimized page clearing */
>> + gfp |= __GFP_ZERO;
>> +
>> + if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
>> + gfp |= GFP_DMA;
>
> What is the significance of ZONE_DMA on this architecture?
>
> Do you actually have DMA masters with a 0x00ffffff mask?
Actually, nios2 doesn't have DMA master with 0x00ffffff mask. I will
change it to return 1, same as some other architectures
implementation.
And the ZONE_DMA stuff will remove as well, it shouldn't have ZONE_DMA
limitation.
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