[PATCH] cciss: disable DMA prefetch on P600
Unconditionally disable DMA prefetch on the P600 controller. An ASIC bug may
result in prefetching beyond the end of physical memory.
Signed-off-by: Mike Miller <mike.miller@hp.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
index 4899ab2..a17223c 100644
--- a/drivers/block/cciss.c
+++ b/drivers/block/cciss.c
@@ -3003,6 +3003,17 @@
}
#endif
+ /* Disabling DMA prefetch for the P600
+ * An ASIC bug may result in a prefetch beyond
+ * physical memory.
+ */
+ if(board_id == 0x3225103C) {
+ __u32 dma_prefetch;
+ dma_prefetch = readl(c->vaddr + I2O_DMA1_CFG);
+ dma_prefetch |= 0x8000;
+ writel(dma_prefetch, c->vaddr + I2O_DMA1_CFG);
+ }
+
#ifdef CCISS_DEBUG
printk("Trying to put board into Simple mode\n");
#endif /* CCISS_DEBUG */