From 212868d387d0033b7e0029326a900126fe5e3d52 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Sun, 28 Jan 2007 12:56:42 -0800 Subject: [PATCH] [AVR32] Fix incorrect invalidation of shared cachelines Fix bug in dma_map_single(..., DMA_FROM_DEVICE) caused by incorrect invalidation of shared cachelines at the beginning and/or end of the specified buffer. Those shared cachelines need to be flushed, since they may hold valid data (which must not be discarded). Signed-off-by: David Brownell Signed-off-by: Haavard Skinnemoen --- arch/avr32/mm/cache.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) diff --git a/arch/avr32/mm/cache.c b/arch/avr32/mm/cache.c index 450515b245a0..fb13f72e9a02 100644 --- a/arch/avr32/mm/cache.c +++ b/arch/avr32/mm/cache.c @@ -22,18 +22,34 @@ void invalidate_dcache_region(void *start, size_t size) { - unsigned long v, begin, end, linesz; + unsigned long v, begin, end, linesz, mask; + int flush = 0; linesz = boot_cpu_data.dcache.linesz; + mask = linesz - 1; + + /* when first and/or last cachelines are shared, flush them + * instead of invalidating ... never discard valid data! + */ + begin = (unsigned long)start; + end = begin + size - 1; + + if (begin & mask) { + flush_dcache_line(start); + begin += linesz; + flush = 1; + } + if ((end & mask) != mask) { + flush_dcache_line((void *)end); + end -= linesz; + flush = 1; + } - //printk("invalidate dcache: %p + %u\n", start, size); - - /* You asked for it, you got it */ - begin = (unsigned long)start & ~(linesz - 1); - end = ((unsigned long)start + size + linesz - 1) & ~(linesz - 1); - - for (v = begin; v < end; v += linesz) + /* remaining cachelines only need invalidation */ + for (v = begin; v <= end; v += linesz) invalidate_dcache_line((void *)v); + if (flush) + flush_write_buffer(); } void clean_dcache_region(void *start, size_t size) -- 2.39.5