[PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH_STATUS register read

[PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH_STATUS register read

[Praveenkumar I]

After each codeword NAND_FLASH_STATUS is read for possible operational
failures. But there is no DMA sync for CPU operation before reading it
and this leads to incorrect or older copy of DMA buffer in reg_read_buf.

This patch adds the DMA sync on reg_read_buf for CPU before reading it.

Fixes: 5bc36b2bf6e2 ("mtd: rawnand: qcom: check for operation errors in case of raw read")
Signed-off-by: Praveenkumar I <ipkumar@codeaurora.org>
---
 drivers/mtd/nand/raw/qcom_nandc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
index bd7a7251429b..5bb85f1ba84c 100644
--- a/drivers/mtd/nand/raw/qcom_nandc.c
+++ b/drivers/mtd/nand/raw/qcom_nandc.c
@@ -1570,6 +1570,8 @@ static int check_flash_errors(struct qcom_nand_host *host, int cw_cnt)
 	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
 	int i;
 
+	nandc_read_buffer_sync(nandc, true);
+
 	for (i = 0; i < cw_cnt; i++) {
 		u32 flash = le32_to_cpu(nandc->reg_read_buf[i]);
 
-- 
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Re: [PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH_STATUS register read

[Miquel Raynal]

Hello,

Praveenkumar I <ipkumar@codeaurora.org> wrote on Fri,  9 Oct 2020
13:37:52 +0530:

> After each codeword NAND_FLASH_STATUS is read for possible operational
> failures. But there is no DMA sync for CPU operation before reading it
> and this leads to incorrect or older copy of DMA buffer in reg_read_buf.
> 
> This patch adds the DMA sync on reg_read_buf for CPU before reading it.
> 
> Fixes: 5bc36b2bf6e2 ("mtd: rawnand: qcom: check for operation errors in case of raw read")

I guess this deserves a proper Cc: stable tag?

> Signed-off-by: Praveenkumar I <ipkumar@codeaurora.org>

I think your full name is required in the SoB line (should match the
authorship).

Otherwise looks good to me.

> ---
>  drivers/mtd/nand/raw/qcom_nandc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index bd7a7251429b..5bb85f1ba84c 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -1570,6 +1570,8 @@ static int check_flash_errors(struct qcom_nand_host *host, int cw_cnt)
>  	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
>  	int i;
>  
> +	nandc_read_buffer_sync(nandc, true);
> +
>  	for (i = 0; i < cw_cnt; i++) {
>  		u32 flash = le32_to_cpu(nandc->reg_read_buf[i]);
>  

Thanks,
Miquèl

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Re: [PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH_STATUS register read

[Miquel Raynal]

Hello,

Praveenkumar I <ipkumar@codeaurora.org> wrote on Wed, 28 Oct 2020
19:48:34 +0530:

> Hi Miquel,
> 
> Please find the inline reply.
> 
> Thanks,
> Praveenkumar I
> 
> 
> On 10/28/2020 3:38 PM, Miquel Raynal wrote:
> > Hello,
> >
> > Praveenkumar I <ipkumar@codeaurora.org> wrote on Fri,  9 Oct 2020
> > 13:37:52 +0530:
> >  
> >> After each codeword NAND_FLASH_STATUS is read for possible operational
> >> failures. But there is no DMA sync for CPU operation before reading it
> >> and this leads to incorrect or older copy of DMA buffer in reg_read_buf.
> >>
> >> This patch adds the DMA sync on reg_read_buf for CPU before reading it.
> >>
> >> Fixes: 5bc36b2bf6e2 ("mtd: rawnand: qcom: check for operation errors in case of raw read")  
> > I guess this deserves a proper Cc: stable tag?  
> >    >> Yes. I will send a V2 Patch with stable tag in Cc  

That's fine for this one, I'll add it myself.

> >> Signed-off-by: Praveenkumar I <ipkumar@codeaurora.org>  
> > I think your full name is required in the SoB line (should match the
> > authorship).  
> >     >> "Praveenkumar I" is my full name and it is same as the authorship.  

Ok, sorry for the confusion.

> > Otherwise looks good to me.
> >  
> >> ---
> >>   drivers/mtd/nand/raw/qcom_nandc.c | 2 ++
> >>   1 file changed, 2 insertions(+)
> >>
> >> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> >> index bd7a7251429b..5bb85f1ba84c 100644
> >> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> >> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> >> @@ -1570,6 +1570,8 @@ static int check_flash_errors(struct qcom_nand_host *host, int cw_cnt)
> >>   	struct qcom_nand_controller *nandc = get_qcom_nand_controller(chip);
> >>   	int i;  
> >>   >> +	nandc_read_buffer_sync(nandc, true);  
> >> +
> >>   	for (i = 0; i < cw_cnt; i++) {
> >>   		u32 flash = le32_to_cpu(nandc->reg_read_buf[i]);  
> >>   > Thanks,  
> > Miquèl  
> 

Cheers,
Miquèl

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Re: [PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH_STATUS register read

[Miquel Raynal]

On Fri, 2020-10-09 at 08:07:52 UTC, Praveenkumar I wrote:
> After each codeword NAND_FLASH_STATUS is read for possible operational
> failures. But there is no DMA sync for CPU operation before reading it
> and this leads to incorrect or older copy of DMA buffer in reg_read_buf.
> 
> This patch adds the DMA sync on reg_read_buf for CPU before reading it.
> 
> Fixes: 5bc36b2bf6e2 ("mtd: rawnand: qcom: check for operation errors in case of raw read")
> Signed-off-by: Praveenkumar I <ipkumar@codeaurora.org>

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.

Miquel

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