* [PATCH] mtd: nand: diskonchip: Replace mdelay with usleep_range in doc_probe
@ 2018-04-11 2:57 Jia-Ju Bai
2018-04-22 17:26 ` Boris Brezillon
0 siblings, 1 reply; 2+ messages in thread
From: Jia-Ju Bai @ 2018-04-11 2:57 UTC (permalink / raw)
To: boris.brezillon, richard, dwmw2, computersforpeace, marek.vasut,
cyrille.pitchen
Cc: linux-mtd, linux-kernel, Jia-Ju Bai
doc_probe() is never called in atomic context.
doc_probe() is only called by init_nanddoc(), which is only set as
a parameter of module_init().
This function is not called in atomic context.
Despite never getting called from atomic context, doc_probe()
calls mdelay() to busily wait.
This is not necessary and can be replaced with usleep_range() to
avoid busy waiting.
This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
drivers/mtd/nand/diskonchip.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
index c3aa53c..2679bc4 100644
--- a/drivers/mtd/nand/diskonchip.c
+++ b/drivers/mtd/nand/diskonchip.c
@@ -1482,12 +1482,12 @@ static int __init doc_probe(unsigned long physadr)
WriteDOC(tmp, virtadr, Mplus_DOCControl);
WriteDOC(~tmp, virtadr, Mplus_CtrlConfirm);
- mdelay(1);
+ usleep_range(1000, 2000);
/* Enable the Millennium Plus ASIC */
tmp = DOC_MODE_NORMAL | DOC_MODE_MDWREN | DOC_MODE_RST_LAT | DOC_MODE_BDECT;
WriteDOC(tmp, virtadr, Mplus_DOCControl);
WriteDOC(~tmp, virtadr, Mplus_CtrlConfirm);
- mdelay(1);
+ usleep_range(1000, 2000);
ChipID = ReadDOC(virtadr, ChipID);
--
1.9.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mtd: nand: diskonchip: Replace mdelay with usleep_range in doc_probe
2018-04-11 2:57 [PATCH] mtd: nand: diskonchip: Replace mdelay with usleep_range in doc_probe Jia-Ju Bai
@ 2018-04-22 17:26 ` Boris Brezillon
0 siblings, 0 replies; 2+ messages in thread
From: Boris Brezillon @ 2018-04-22 17:26 UTC (permalink / raw)
To: Jia-Ju Bai
Cc: boris.brezillon, richard, dwmw2, computersforpeace, marek.vasut,
cyrille.pitchen, linux-mtd, linux-kernel
On Wed, 11 Apr 2018 10:57:57 +0800
Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
> doc_probe() is never called in atomic context.
>
> doc_probe() is only called by init_nanddoc(), which is only set as
> a parameter of module_init().
> This function is not called in atomic context.
>
> Despite never getting called from atomic context, doc_probe()
> calls mdelay() to busily wait.
> This is not necessary and can be replaced with usleep_range() to
> avoid busy waiting.
>
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
> drivers/mtd/nand/diskonchip.c | 4 ++--
Applied to nand/next after fixing the subject prefix and the file path.
Thanks,
Boris
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/diskonchip.c b/drivers/mtd/nand/diskonchip.c
> index c3aa53c..2679bc4 100644
> --- a/drivers/mtd/nand/diskonchip.c
> +++ b/drivers/mtd/nand/diskonchip.c
> @@ -1482,12 +1482,12 @@ static int __init doc_probe(unsigned long physadr)
> WriteDOC(tmp, virtadr, Mplus_DOCControl);
> WriteDOC(~tmp, virtadr, Mplus_CtrlConfirm);
>
> - mdelay(1);
> + usleep_range(1000, 2000);
> /* Enable the Millennium Plus ASIC */
> tmp = DOC_MODE_NORMAL | DOC_MODE_MDWREN | DOC_MODE_RST_LAT | DOC_MODE_BDECT;
> WriteDOC(tmp, virtadr, Mplus_DOCControl);
> WriteDOC(~tmp, virtadr, Mplus_CtrlConfirm);
> - mdelay(1);
> + usleep_range(1000, 2000);
>
> ChipID = ReadDOC(virtadr, ChipID);
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-04-11 2:57 [PATCH] mtd: nand: diskonchip: Replace mdelay with usleep_range in doc_probe Jia-Ju Bai
2018-04-22 17:26 ` Boris Brezillon
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