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

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Praveenkumar I <ipkumar@codeaurora.org>
Cc: richard@nod.at, vigneshr@ti.com, sivaprak@codeaurora.org,
	peter.ujfalusi@ti.com, boris.brezillon@collabora.com,
	linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org,
	stable@vger.kernel.org, kathirav@codeaurora.org
Subject: Re: [PATCH] mtd: rawnand: qcom: Fix DMA sync on FLASH_STATUS register read
Date: Wed, 28 Oct 2020 11:08:35 +0100	[thread overview]
Message-ID: <20201028110835.2f319c0a@xps13> (raw)
In-Reply-To: <1602230872-25616-1-git-send-email-ipkumar@codeaurora.org>

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