dmaengine/amba-pl08x: Align lli_len to max(src.width, dst.width)
Currently lli_len is aligned to min of two widths, which looks to be incorrect. Instead it should be aligned to max of both widths. Lets say, total_size = 441 bytes MIN: lets check if min() suits or not: CASE 1: srcwidth = 1, dstwidth = 4 min(src, dst) = 1 i.e. We program transfer size in control reg to 441. Now, till 440 bytes everything is fine, but on the last byte DMAC can't transfer 1 byte to dst, as its width is 4. CASE 2: srcwidth = 4, dstwidth = 1 min(src, dst) = 1 i.e. we program transfer size in control reg to 110 (data transferred = 110 * srcwidth). So, here too 1 byte is left, but on the source side. MAX: Lets check if max() suits or not: CASE 3: srcwidth = 1, dstwidth = 4 max(src, dst) = 4 Aligned size is 440 i.e. We program transfer size in control reg to 440. Now, all 440 bytes will be transferred without any issues. CASE 4: srcwidth = 4, dstwidth = 1 max(src, dst) = 4 Aligned size is 440 i.e. We program transfer size in control reg to 110 (data transferred = 110 * srcwidth). Now, also all 440 bytes will be transferred without any issues. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
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@ -669,20 +669,22 @@ static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
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* width left
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*/
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while (bd.remainder > (mbus->buswidth - 1)) {
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size_t lli_len, tsize;
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size_t lli_len, tsize, width;
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/*
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* If enough left try to send max possible,
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* otherwise try to send the remainder
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*/
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lli_len = min(bd.remainder, max_bytes_per_lli);
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/*
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* Check against minimum bus alignment: Calculate actual
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* Check against maximum bus alignment: Calculate actual
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* transfer size in relation to bus width and get a
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* maximum remainder of the smallest bus width - 1
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* maximum remainder of the highest bus width - 1
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*/
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tsize = lli_len / min(mbus->buswidth, sbus->buswidth);
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lli_len = tsize * min(mbus->buswidth, sbus->buswidth);
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width = max(mbus->buswidth, sbus->buswidth);
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lli_len = (lli_len / width) * width;
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tsize = lli_len / bd.srcbus.buswidth;
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dev_vdbg(&pl08x->adev->dev,
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"%s fill lli with single lli chunk of "
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