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[4/8] spi: davinci: flush caches when performing DMA

Message ID 1486740584-17875-5-git-send-email-fisaksen@baylibre.com (mailing list archive)
State New, archived
Headers show

Commit Message

Frode Isaksen Feb. 10, 2017, 3:29 p.m. UTC 
This CPU has VIVT caches, so need to flush the
cache for vmalloc'ed buffers, since the address
may be aliased (same phyiscal address used by
multiple virtual addresses).
This fixes errors when mounting and reading/writing
UBIFS volumes with SPI flash.

Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
---
 drivers/spi/spi-davinci.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
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Patch

diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index f1b46f6..c735425 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -29,6 +29,7 @@ 
 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>
 #include <linux/slab.h>
+#include <asm/cacheflush.h>
 
 #include <linux/platform_data/spi-davinci.h>
 
@@ -676,7 +677,9 @@  static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 			}
 			sg_dma_address(&sg_rx) = t->rx_dma;
 			sg_dma_len(&sg_rx) = t->len;
-		}
+		} else if (is_vmalloc_addr(t->rx_buf))
+			/* VIVT cache, flush since aliased address */
+			flush_kernel_vmap_range((void *)t->rx_buf, t->len);
 
 		sg_init_table(&sg_tx, 1);
 		if (!t->tx_buf) {
@@ -688,7 +691,9 @@  static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 			}
 			sg_dma_address(&sg_tx) = t->tx_dma;
 			sg_dma_len(&sg_tx) = t->len;
-		}
+		} else if (is_vmalloc_addr(t->tx_buf))
+			/* VIVT cache, flush since aliased address */
+			flush_kernel_vmap_range((void *)t->tx_buf, t->len);
 
 		rxdesc = dmaengine_prep_slave_sg(dspi->dma_rx,
 				t->rx_sg.sgl ?: &sg_rx, t->rx_sg.nents ?: 1,
@@ -741,6 +746,10 @@  static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
 		if (!t->rx_buf)
 			dma_unmap_single(&spi->dev, t->rx_dma,
 					t->len, DMA_FROM_DEVICE);
+		else if (is_vmalloc_addr(t->rx_buf))
+			/* VIVT cache, invalidate since aliased address */
+			invalidate_kernel_vmap_range((void *)t->rx_buf, t->len);
+
 		if (!t->tx_buf)
 			dma_unmap_single(&spi->dev, t->tx_dma,
 					t->len, DMA_TO_DEVICE);