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    SubjectRe: [PATCH V4 3/5] dmaengine/dw_dmac: Divide one sg to many desc, if sg len is greater than DWC_MAX_COUNT
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    On Mon, 2011-05-09 at 11:33 +0530, viresh kumar wrote:
    > On 05/09/2011 10:50 AM, Koul, Vinod wrote:
    > >> > @@ -695,9 +695,15 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
    > >> > reg = dws->tx_reg;
    > >> > for_each_sg(sgl, sg, sg_len, i) {
    > >> > struct dw_desc *desc;
    > >> > - u32 len;
    > >> > - u32 mem;
    > >> > + u32 len, dlen, mem;
    > >> >
    > >> > + mem = sg_phys(sg);
    > >> > + len = sg_dma_len(sg);
    > >> > + mem_width = 2;
    > > hardcoding mem_width doesn't make sense, you should take this from input
    > > params
    >
    > Firstly, this change is not introduced in this patch, i have just rearranged this.
    > So, will send separate patch if this change is required.
    >
    > Secondly, peripheral width is taken from chan->private. And by 2 for mem_width,
    > we meant word-by-word here. Shouldn't we always try word-by-word here?
    > How should we pass width for memory?
    Ah, then there is another todo for this driver. Move from chan->private
    to DMA_SLAVE_CONFIG.

    struct dma_slave_config has dedicated fields for both source and
    destination widths, src_addr_width & dst_addr_width please use them...
    You should pass this structure to device control API as:
    dmaengine_device_control(
    chan, DMA_SLAVE_CONFIG, (unsigned long)&slave_config);

    --
    ~Vinod



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