Re: [PATCH] mtd: rawnand: qcom: Fix broken misc_cmd_type in exec_op

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Christian Marangi <ansuelsmth@gmail.com>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Richard Weinberger <richard@nod.at>,
	Vignesh Raghavendra <vigneshr@ti.com>,
	Sricharan Ramabadhran <quic_srichara@quicinc.com>,
	Md Sadre Alam <quic_mdalam@quicinc.com>,
	linux-mtd@lists.infradead.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] mtd: rawnand: qcom: Fix broken misc_cmd_type in exec_op
Date: Wed, 20 Mar 2024 08:07:37 +0100	[thread overview]
Message-ID: <20240320080737.00e7bb37@xps-13> (raw)
In-Reply-To: <20240320001141.16560-1-ansuelsmth@gmail.com>

Hi Christian,

ansuelsmth@gmail.com wrote on Wed, 20 Mar 2024 01:11:39 +0100:

> misc_cmd_type in exec_op have multiple problems. With commit a82990c8a409
> ("mtd: rawnand: qcom: Add read/read_start ops in exec_op path") it was
> reworked and generalized but actually dropped the handling of the
> RESET_DEVICE command.
> 
> The rework itself was correct with supporting case where a single misc
> command is handled, but became problematic by the addition of exiting
> early if we didn't had an ERASE or an OP_PROGRAM_PAGE operation.
> 
> Also additional logic was added without clear explaination causing the
> erase command to be broken on testing it on a ipq806x nandc.
> 
> Add some additional logic to restore RESET_DEVICE command handling and
> fix erase command.
> 
> Fixes: a82990c8a409 ("mtd: rawnand: qcom: Add read/read_start ops in exec_op path")
> Cc: stable@vger.kernel.org
> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> ---
>  drivers/mtd/nand/raw/qcom_nandc.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> index b079605c84d3..b8cff9240b28 100644
> --- a/drivers/mtd/nand/raw/qcom_nandc.c
> +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> @@ -2815,7 +2815,7 @@ static int qcom_misc_cmd_type_exec(struct nand_chip *chip, const struct nand_sub
>  			      host->cfg0_raw & ~(7 << CW_PER_PAGE));
>  		nandc_set_reg(chip, NAND_DEV0_CFG1, host->cfg1_raw);
>  		instrs = 3;
> -	} else {
> +	} else if (q_op.cmd_reg != OP_RESET_DEVICE) {
>  		return 0;
>  	}
>  
> @@ -2830,9 +2830,8 @@ static int qcom_misc_cmd_type_exec(struct nand_chip *chip, const struct nand_sub
>  	nandc_set_reg(chip, NAND_EXEC_CMD, 1);
>  
>  	write_reg_dma(nandc, NAND_FLASH_CMD, instrs, NAND_BAM_NEXT_SGL);
> -	(q_op.cmd_reg == OP_BLOCK_ERASE) ? write_reg_dma(nandc, NAND_DEV0_CFG0,
> -	2, NAND_BAM_NEXT_SGL) : read_reg_dma(nandc,
> -	NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);
> +	if (q_op.cmd_reg == OP_BLOCK_ERASE)
> +		write_reg_dma(nandc, NAND_DEV0_CFG0, 2, NAND_BAM_NEXT_SGL);

Ugh. How did that went through...

I don't want to get into the details of this controller, but the fix
looks legitimate.

>  	write_reg_dma(nandc, NAND_EXEC_CMD, 1, NAND_BAM_NEXT_SGL);
>  	read_reg_dma(nandc, NAND_FLASH_STATUS, 1, NAND_BAM_NEXT_SGL);

Thanks,
Miquèl