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>
Loading
Please register or sign in to comment