Clang produces the following warning drivers/dma/mv_xor_v2.c:264:40: warning: shifting a negative signed value is undefined [-Wshift-negative-value] reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK << MV_XOR_V2_DMA_IMSG_THRD_SHIFT); ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ drivers/dma/mv_xor_v2.c:271:46: warning: shifting a negative signed value is undefined [-Wshift-negative-value] reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK << ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ Upon further investigation MV_XOR_V2_DMA_IMSG_THRD_SHIFT and MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT are both 0. Since shifting by 0 does nothing, these variables can be removed. Cc: clang-built-linux@xxxxxxxxxxxxxxxx Link: https://github.com/ClangBuiltLinux/linux/issues/521 Signed-off-by: Nathan Huckleberry <nhuck@xxxxxxxxxx> --- drivers/dma/mv_xor_v2.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c index fa5dab481203..5d2e0d1f3ec9 100644 --- a/drivers/dma/mv_xor_v2.c +++ b/drivers/dma/mv_xor_v2.c @@ -33,7 +33,6 @@ #define MV_XOR_V2_DMA_IMSG_CDAT_OFF 0x014 #define MV_XOR_V2_DMA_IMSG_THRD_OFF 0x018 #define MV_XOR_V2_DMA_IMSG_THRD_MASK 0x7FFF -#define MV_XOR_V2_DMA_IMSG_THRD_SHIFT 0x0 #define MV_XOR_V2_DMA_IMSG_TIMER_EN BIT(18) #define MV_XOR_V2_DMA_DESQ_AWATTR_OFF 0x01C /* Same flags as MV_XOR_V2_DMA_DESQ_ARATTR_OFF */ @@ -50,7 +49,6 @@ #define MV_XOR_V2_DMA_DESQ_ADD_OFF 0x808 #define MV_XOR_V2_DMA_IMSG_TMOT 0x810 #define MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK 0x1FFF -#define MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT 0 /* XOR Global registers */ #define MV_XOR_V2_GLOB_BW_CTRL 0x4 @@ -261,16 +259,15 @@ void mv_xor_v2_enable_imsg_thrd(struct mv_xor_v2_device *xor_dev) /* Configure threshold of number of descriptors, and enable timer */ reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF); - reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK << MV_XOR_V2_DMA_IMSG_THRD_SHIFT); - reg |= (MV_XOR_V2_DONE_IMSG_THRD << MV_XOR_V2_DMA_IMSG_THRD_SHIFT); + reg &= (~MV_XOR_V2_DMA_IMSG_THRD_MASK); + reg |= (MV_XOR_V2_DONE_IMSG_THRD); reg |= MV_XOR_V2_DMA_IMSG_TIMER_EN; writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_THRD_OFF); /* Configure Timer Threshold */ reg = readl(xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT); - reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK << - MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT); - reg |= (MV_XOR_V2_TIMER_THRD << MV_XOR_V2_DMA_IMSG_TIMER_THRD_SHIFT); + reg &= (~MV_XOR_V2_DMA_IMSG_TIMER_THRD_MASK); + reg |= (MV_XOR_V2_TIMER_THRD); writel(reg, xor_dev->dma_base + MV_XOR_V2_DMA_IMSG_TMOT); } -- 2.22.0.rc2.383.gf4fbbf30c2-goog