On 02.03.21 09:37, Ahmad Fatoum wrote:
> Hello Jules, Yann,
>
>> +void dma_sync_single_for_device(dma_addr_t addr, size_t size,
>> + enum dma_data_direction dir)
>> +{
>> + switch (dir) {
>> + case DMA_FROM_DEVICE:
>> + kvx_dcache_invalidate_mem_area(addr, size);
>> + break;
>> + case DMA_TO_DEVICE:
>> + case DMA_BIDIRECTIONAL:
>> + /* allow device to read buffer written by CPU */
>> + wmb();
>
> If the interconnect was indeed coherent, like dma_alloc_coherent
> above hints, you wouldn't need any barriers here..?
Wrong context. You wouldn't need the cache invalidation* above.
>
>> + break;
>> + default:
>> + BUG();
>> + }
>> +}
>> +
>> +void dma_sync_single_for_cpu(dma_addr_t addr, size_t size,
>> + enum dma_data_direction dir)
>> +{
>> + switch (dir) {
>> + case DMA_FROM_DEVICE:
>> + case DMA_TO_DEVICE:
>> + break;
>> + case DMA_BIDIRECTIONAL:
>> + kvx_dcache_invalidate_mem_area(addr, size);
>> + break;
>> + default:
>> + BUG();
>> + }
>> +}
>> +
>> +#define KVX_DDR_ALIAS_OFFSET \
>> + (KVX_DDR_64BIT_RAM_WINDOW_BA - KVX_DDR_32BIT_RAM_WINDOW_BA)
>> +#define KVX_DDR_ALIAS_WINDOW \
>> + (KVX_DDR_64BIT_RAM_WINDOW_BA + KVX_DDR_ALIAS_OFFSET)
>> +
>> +/* Local smem is aliased between 0 and 16MB */
>> +#define KVX_SMEM_LOCAL_ALIAS 0x1000000ULL
>> +
>> +dma_addr_t dma_map_single(struct device_d *dev, void *ptr, size_t size,
>> + enum dma_data_direction dir)
>> +{
>> + uintptr_t addr = (uintptr_t) ptr;
>> +
>> + dma_sync_single_for_device(addr, size, dir);
>> +
>> + /* Local smem alias should never be used for dma */
>> + if (addr < KVX_SMEM_LOCAL_ALIAS)
>> + return addr + (1 + kvx_cluster_id()) * KVX_SMEM_LOCAL_ALIAS;
>> +
>> + if (dev->dma_mask && addr <= dev->dma_mask)
>> + return addr;
>> +
>> + if (addr >= KVX_DDR_ALIAS_WINDOW)
>> + return DMA_ERROR_CODE;
>> +
>> + addr -= KVX_DDR_ALIAS_OFFSET;
>> + if (dev->dma_mask && addr > dev->dma_mask)
>> + return DMA_ERROR_CODE;
>> +
>> + return addr;
>> +}
>> +
>> +void dma_unmap_single(struct device_d *dev, dma_addr_t addr, size_t size,
>> + enum dma_data_direction dir)
>> +{
>> + dma_sync_single_for_cpu(addr, size, dir);
>> +}
>>
>
--
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