[PATCH v3] mtd: nand: brcmnand: Disable prefetch by default

Kamal Dasu
2018-01-08T20:37:17Z

Brcm nand controller prefetch feature needs to be disabled
by default. Enabling affects performance on random reads as
well as dma reads.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller")
Cc: stable@vger.kernel.org
---
drivers/mtd/nand/brcmnand/brcmnand.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/mtd/nand/brcmnand/brcmnand.c b/drivers/mtd/nand/brcmnand/brcmnand.c
index dd56a67..2a978d9 100644
--- a/drivers/mtd/nand/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/brcmnand/brcmnand.c
@@ -2193,16 +2193,9 @@ static int brcmnand_setup_dev(struct brcmnand_host *host)
if (ctrl->nand_version >= 0x0702)
tmp |= ACC_CONTROL_RD_ERASED;
tmp &= ~ACC_CONTROL_FAST_PGM_RDIN;
- if (ctrl->features & BRCMNAND_HAS_PREFETCH) {
- /*
- * FIXME: Flash DMA + prefetch may see spurious erased-page ECC
- * errors
- */
- if (has_flash_dma(ctrl))
- tmp &= ~ACC_CONTROL_PREFETCH;
- else
- tmp |= ACC_CONTROL_PREFETCH;
- }
+ if (ctrl->features & BRCMNAND_HAS_PREFETCH)
+ tmp &= ~ACC_CONTROL_PREFETCH;
+
nand_writereg(ctrl, offs, tmp);

return 0;
--
2.7.4