On 30/10/2015 13:53, Arnd Bergmann wrote:
On Monday 26 October 2015 22:14:58 John Garry wrote:
+ /*
+ * DMA-map SMP request, response buffers
+ */
+ /* req */
+ sg_req = &task->smp_task.smp_req;
+ elem = dma_map_sg(dev, sg_req, 1, DMA_TO_DEVICE);
+ if (!elem)
+ return -ENOMEM;
+ req_len = sg_dma_len(sg_req);
+ req_dma_addr = sg_dma_address(sg_req);
If you only use the first element, could you just use dma_map_single()?
Can do. Actually sg_req seems only ever has one element:
expander.c, smp_execute_task()
sg_init_one(&task->smp_task.smp_req, req, req_size);
+ hdr->cmd_table_addr_lo = cpu_to_le32(lower_32_bits(req_dma_addr));
+ hdr->cmd_table_addr_hi = cpu_to_le32(upper_32_bits(req_dma_addr));
+
+ hdr->sts_buffer_addr_lo =
+ cpu_to_le32(lower_32_bits(slot->status_buffer_dma));
+ hdr->sts_buffer_addr_hi =
+ cpu_to_le32(upper_32_bits(slot->status_buffer_dma));
+
I see these a lot in your code. Could you replace this wit
hdr->cmd_table_addr = cpu_to_le64(req_dma_addr);
This seems reasonable. They are not swapped.
and so on? That would be much more readable. Or are the two __le32 variables
swapped? If so, you could add a small helper function like
static inline __le64 cpu_to_le64_wordswapped(u64 val)
{
return cpu_to_le64(val >> 32 | val << 32);
}
Arnd
.
cheers
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