linux-kernel - Re: [PATCH v2 1/2] mtd: rawnand: qcom: Fix broken erase in misc_cmd_type in exec

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Message-ID: <20240326073947.GA9565@thinkpad>
Date: Tue, 26 Mar 2024 13:09:47 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Christian Marangi <ansuelsmth@...il.com>
Cc: Miquel Raynal <miquel.raynal@...tlin.com>,
	Richard Weinberger <richard@....at>,
	Vignesh Raghavendra <vigneshr@...com>,
	Md Sadre Alam <quic_mdalam@...cinc.com>,
	Sricharan Ramabadhran <quic_srichara@...cinc.com>,
	linux-mtd@...ts.infradead.org, linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH v2 1/2] mtd: rawnand: qcom: Fix broken erase in
 misc_cmd_type in exec_op

On Tue, Mar 26, 2024 at 12:55:19PM +0530, Manivannan Sadhasivam wrote:
> On Mon, Mar 25, 2024 at 11:30:47AM +0100, Christian Marangi wrote:
> > 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 broke the handling of the
> > ERASE_BLOCK command.
> > 
> > Additional logic was added to the erase command cycle without clear
> > explaination causing the erase command to be broken on testing it on
> > a ipq806x nandc.
> > 
> > Fix the erase command by reverting the additional logic and only adding
> > the NAND_DEV0_CFG0 additional call (required for erase command).
> > 
> > Fixes: a82990c8a409 ("mtd: rawnand: qcom: Add read/read_start ops in exec_op path")
> > Cc: stable@...r.kernel.org
> > Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
> > ---
> > Changes v2:
> > - Split this and rework commit description and title
> > 
> >  drivers/mtd/nand/raw/qcom_nandc.c | 5 ++---
> >  1 file changed, 2 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mtd/nand/raw/qcom_nandc.c b/drivers/mtd/nand/raw/qcom_nandc.c
> > index b079605c84d3..19d76e345a49 100644
> > --- a/drivers/mtd/nand/raw/qcom_nandc.c
> > +++ b/drivers/mtd/nand/raw/qcom_nandc.c
> > @@ -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);
> 
> So this only avoids the call to, 'read_reg_dma(nandc, NAND_FLASH_STATUS, 1,
> NAND_BAM_NEXT_SGL)' if q_op.cmd_reg != OP_BLOCK_ERASE. But for q_op.cmd_reg ==
> OP_BLOCK_ERASE, the result is the same.
> 
> I'm wondering how it results in fixing the OP_BLOCK_ERASE command.
> 

Perhaps you are trying to fix the OP_RESET_DEVICE command altogether?

- Mani

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