lkml.org 
[lkml]   [2011]   [May]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH V4 3/5] dmaengine/dw_dmac: Divide one sg to many desc, if sg len is greater than DWC_MAX_COUNT
From
Date
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



\
 
 \ /
  Last update: 2011-05-09 08:23    [from the cache]
©2003-2011 Jasper Spaans