From 9d47d1316da6585bbafe141e42bbdcdfd562bc71 Mon Sep 17 00:00:00 2001 From: Ye Li Date: Fri, 4 Jan 2019 09:24:14 +0000 Subject: [PATCH] arm: Round the dma_alloc_coherent memory size to cache line aligned When running usb dwc3 gadget driver, we meet random USB enumeration failure in fastboot. The root cause is a cache coherence issue. When it happens, the ctrl_req in gadget driver is allocated at 0xfe932f40, and the usb_composite_dev (cdev) is allocated at 0xfe932f60. So after we submit the setup request (cache flushed) to USB controller, any accessing to usb_composite_dev variable will cause the cache line refill, then when setup transfer is completed, reading the setup data in ctrl_req will gets old value from cache not from memory. The ctrl_req is allocated by API dma_alloc_coherent, but u-boot don't have cohernet memory. so it still needs cache maintain operations before/after HW accessing. Since the cache flush or invalidate bases on cache line, so when the allocated memory size is not cache line aligned, potentially it may meet such issue. This patch modifies the dma_alloc_coherent API to round the size to cache line aligned. Signed-off-by: Ye Li Reviewed-by: Peng Fan --- arch/arm/include/asm/dma-mapping.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h index 0883b7ea75..fc5b8f634d 100644 --- a/arch/arm/include/asm/dma-mapping.h +++ b/arch/arm/include/asm/dma-mapping.h @@ -13,7 +13,7 @@ static inline void *dma_alloc_coherent(size_t len, unsigned long *handle) { - *handle = (unsigned long)memalign(ARCH_DMA_MINALIGN, len); + *handle = (unsigned long)memalign(ARCH_DMA_MINALIGN, ROUND(len, ARCH_DMA_MINALIGN)); return (void *)*handle; } -- 2.39.5