32-bit ARM kernels may have a 64-bit dma_addr_t but have no implementation of the compiler helper for 64-bit unsigned division, therefore the use of the modulo operator in pl330_prep_dma_memcpy causes the link error "undefined reference to `__aeabi_uldivmod'" As the burst value is always a power of two we can fix the problem, and make the code more efficient, by replacing "% burst" with "& (burst-1)". Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx> Signed-off-by: Jon Medhurst <tixy@xxxxxxxxxx> --- Vinod. I haven't added a 'Fixes:' line because I was unsure if the patch in linux-next is part of a stable branch or if the SHA1 might change before hitting mainline. If it stable then the line should be... Fixes: 63369d0a96dc ("dmaengine: pl330: Align DMA memcpy operations to MFIFO width") drivers/dma/pl330.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 38c9617..52c4c62 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -2464,11 +2464,8 @@ pl330_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst, * parameters because our DMA programming algorithm doesn't cope with * transfers which straddle an entry in the DMA device's MFIFO. */ - while (burst > 1) { - if (!((src | dst | len) % burst)) - break; + while ((src | dst | len) & (burst - 1)) burst /= 2; - } desc->rqcfg.brst_size = 0; while (burst != (1 << desc->rqcfg.brst_size)) -- 2.1.1 -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html