diff options
| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-09-13 14:58:49 +0900 |
|---|---|---|
| committer | Boris Brezillon <boris.brezillon@bootlin.com> | 2018-09-15 10:05:26 +0200 |
| commit | cf51e4b9c34407bf0c3d9b582b7837e047e1df47 (patch) | |
| tree | 67c7174f879318cb5fd625f8f0eee0a61e85ee34 /drivers/mtd | |
| parent | 21a268069203cc72d1b2990bc68386516fabc274 (diff) | |
| download | linux-cf51e4b9c34407bf0c3d9b582b7837e047e1df47.tar.bz2 | |
mtd: rawnand: denali: fix a race condition when DMA is kicked
I thought the read-back of the DMA_ENABLE register was unnecessary
(at least it is working on my boards), then deleted it in commit
586a2c52909d ("mtd: nand: denali: squash denali_enable_dma() helper
into caller"). Sorry, I was wrong - it caused a timing issue on
Cyclone5 SoCFPGAs.
Revive the register read-back, commenting why this is necessary.
Fixes: 586a2c52909d ("mtd: nand: denali: squash denali_enable_dma() helper into caller")
Cc: <stable@vger.kernel.org>
Reported-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Diffstat (limited to 'drivers/mtd')
| -rw-r--r-- | drivers/mtd/nand/raw/denali.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/mtd/nand/raw/denali.c b/drivers/mtd/nand/raw/denali.c index 67b2065e7a19..b864b93dd289 100644 --- a/drivers/mtd/nand/raw/denali.c +++ b/drivers/mtd/nand/raw/denali.c @@ -596,6 +596,12 @@ static int denali_dma_xfer(struct denali_nand_info *denali, void *buf, } iowrite32(DMA_ENABLE__FLAG, denali->reg + DMA_ENABLE); + /* + * The ->setup_dma() hook kicks DMA by using the data/command + * interface, which belongs to a different AXI port from the + * register interface. Read back the register to avoid a race. + */ + ioread32(denali->reg + DMA_ENABLE); denali_reset_irq(denali); denali->setup_dma(denali, dma_addr, page, write); |