Re: [PATCH v2 2/5] mtd: nand: Qualcomm NAND controller driver
From: Archit Taneja
Date: Thu Jul 30 2015 - 02:53:58 EST
On 7/30/2015 12:03 AM, Stephen Boyd wrote:
On 07/29, Archit Taneja wrote:
On 07/29/2015 07:18 AM, Stephen Boyd wrote:
On 07/27/2015 09:34 PM, Archit Taneja wrote:
Hi,
On 07/25/2015 06:21 AM, Stephen Boyd wrote:
On 07/21/2015 03:34 AM, Archit Taneja wrote:
+ int size)
+{Looks like a
+ struct desc_info *desc;
+ struct dma_async_tx_descriptor *dma_desc;
+ struct scatterlist *sgl;
+ int r;
+
+ desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+ if (!desc)
+ return -ENOMEM;
+
+ list_add_tail(&desc->list, &this->list);
+
+ sgl = &desc->sgl;
+
+ sg_init_one(sgl, vaddr, size);
+
+ desc->dir = DMA_MEM_TO_DEV;
+
+ r = dma_map_sg(this->dev, sgl, 1, desc->dir);
+ if (r == 0)
+ goto err;
Should we return an error in this case? Looks like return 0.
dma_map_sg returns the number of sg entries successfully mapped. In
this case, it should be 1.
Right, but this function returns 0 (success?) if we failed to map anything.
Yes. The return value is number of entries successfully mapped.
dma_map_sg is a macro that is replaced by dma_map_sg_attrs. Its
comment
says:
"dma_maps_sg_attrs returns 0 on error and > 0 on success. It should
never return a value < 0."
Yes, and so this function that calls dma_map_sg() is going to
return 0 to the caller when it didn't do what it was asked to do?
Ah, I get your point now :p. I thought you were referring to the
return value of dma_map_sg, and not write_data_dma. Will fix this.
Archit
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