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dmaengine: stm32-dma: avoid 64-bit division in stm32_dma_get_max_width
[ Upstream commit2498363310
] Using the % operator on a 64-bit variable is expensive and can cause a link failure: arm-linux-gnueabi-ld: drivers/dma/stm32-dma.o: in function `stm32_dma_get_max_width': stm32-dma.c:(.text+0x170): undefined reference to `__aeabi_uldivmod' arm-linux-gnueabi-ld: drivers/dma/stm32-dma.o: in function `stm32_dma_set_xfer_param': stm32-dma.c:(.text+0x1cd4): undefined reference to `__aeabi_uldivmod' As we know that we just want to check the alignment in stm32_dma_get_max_width(), there is no need for a full division, and using a simple mask is a faster replacement. Same in stm32_dma_set_xfer_param(), change this to only allow burst transfers if the address is a multiple of the length. stm32_dma_get_best_burst just after will take buf_len into account to fix burst in case of misalignment. Fixes:b20fd5fa31
("dmaengine: stm32-dma: fix stm32_dma_get_max_width") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com> Link: https://lore.kernel.org/r/20211103153312.41483-1-amelie.delaunay@foss.st.com Signed-off-by: Vinod Koul <vkoul@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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1 changed files with 3 additions and 3 deletions
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@ -280,7 +280,7 @@ static enum dma_slave_buswidth stm32_dma_get_max_width(u32 buf_len,
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max_width > DMA_SLAVE_BUSWIDTH_1_BYTE)
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max_width = max_width >> 1;
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if (buf_addr % max_width)
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if (buf_addr & (max_width - 1))
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max_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
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return max_width;
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@ -756,7 +756,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
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* Set memory burst size - burst not possible if address is not aligned on
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* the address boundary equal to the size of the transfer
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*/
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if (buf_addr % buf_len)
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if (buf_addr & (buf_len - 1))
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src_maxburst = 1;
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else
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src_maxburst = STM32_DMA_MAX_BURST;
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@ -812,7 +812,7 @@ static int stm32_dma_set_xfer_param(struct stm32_dma_chan *chan,
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* Set memory burst size - burst not possible if address is not aligned on
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* the address boundary equal to the size of the transfer
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*/
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if (buf_addr % buf_len)
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if (buf_addr & (buf_len - 1))
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dst_maxburst = 1;
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else
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dst_maxburst = STM32_DMA_MAX_BURST;
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