linux-kernel - Re: [PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH

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Message-ID: <20201028152302.2f830077@xps13>
Date:   Wed, 28 Oct 2020 15:23:02 +0100
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Praveenkumar I <ipkumar@...eaurora.org>
Cc:     richard@....at, vigneshr@...com, sivaprak@...eaurora.org,
        peter.ujfalusi@...com, boris.brezillon@...labora.com,
        linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org, kathirav@...eaurora.org
Subject: Re: [PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH_STATUS
 register read

Hello,

Praveenkumar I <ipkumar@...eaurora.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@...eaurora.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@...eaurora.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