* [PATCH v2] mtd: nand: brcmnand: Disable prefetch by default
@ 2018-01-08 20:06 Kamal Dasu
2018-01-08 20:15 ` Boris Brezillon
0 siblings, 1 reply; 2+ messages in thread
From: Kamal Dasu @ 2018-01-08 20:06 UTC (permalink / raw)
To: boris.brezillon, linux-mtd, bcm-kernel-feedback-list
Cc: computersforpeace, richard, dwmw2, marek.vasut, cyrille.pitchen,
Kamal Dasu, stable
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>
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
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH v2] mtd: nand: brcmnand: Disable prefetch by default
2018-01-08 20:06 [PATCH v2] mtd: nand: brcmnand: Disable prefetch by default Kamal Dasu
@ 2018-01-08 20:15 ` Boris Brezillon
0 siblings, 0 replies; 2+ messages in thread
From: Boris Brezillon @ 2018-01-08 20:15 UTC (permalink / raw)
To: Kamal Dasu
Cc: linux-mtd, bcm-kernel-feedback-list, computersforpeace, richard,
dwmw2, marek.vasut, cyrille.pitchen, stable
On Mon, 8 Jan 2018 15:06:13 -0500
Kamal Dasu <kdasu.kdev@gmail.com> wrote:
> 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>
> Cc: stable@vger.kernel.org
Fixes:????
> ---
> 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;
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2018-01-08 20:16 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-01-08 20:06 [PATCH v2] mtd: nand: brcmnand: Disable prefetch by default Kamal Dasu
2018-01-08 20:15 ` Boris Brezillon
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox