linux-kernel - Re: [PATCH V1] drivers:mtd:spi-nor:checkup FSR error bits

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Date:   Thu, 30 Nov 2017 14:40:37 +0000
From:   "Bean Huo (beanhuo)" <beanhuo@...ron.com>
To:     Cyrille Pitchen <cyrille.pitchen@...ev4u.fr>,
        "marek.vasut@...il.com" <marek.vasut@...il.com>
CC:     "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        "computersforpeace@...il.com" <computersforpeace@...il.com>,
        "dwmw2@...radead.org" <dwmw2@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V1] drivers:mtd:spi-nor:checkup FSR error bits

Hi, Cyrille

Finally, I get your comments, thanks.

>Hi Bean,
>
>Le 11/11/2017 à 21:49, Bean Huo (beanhuo) a écrit :
>> For the Micron SPI NOR, when the erase/program operation fails,
>> especially,
>
>To be verified but I think you'd rather remove "the" words in this case:
>
>"For Micron SPI NOR memories, when erase/program operation fails,
>especially ..."
>
>Maybe no comma after "especially".
>
>> for the failure results from intending to modify protected space,
>> spi-nor upper layers still get the return which shows the operation succeeds.
>> this because spi_nor_fsr_ready() only uses bit.7 to device whether ready.
>
>"This": missing capital letter and maybe a verb too.
>
>> For the most cases, even the error of erase/program occurs, SPI NOR
>> device is still ready. The device ready and the error are two different cases.
>
When the program/erase failed, or there is the error during
Erasing/programming, user space always gets the status of the
previous operation is successful.  Because current spi_nor_fsr_ready()
only checks FSR ready bit. Even if failure/error happened, spi nor
device still can go into the ready stage. This is what I want to say.
So, the device ready and the operation failure are two different cases.

>I don't really understand what you mean here.
>
>> This patch is to fixup this issue and adding FSR (flag status
>> register)
>
>This patch fixes the issue by checking relevant bits in the FSR.
>
>> error bits checkup.
>> The FSR(flag status register) is a powerful tool to investigate the
>> staus
>
>"The FSR (flag status register)": please insert a space ' '.
>
>s/staus/status/
>
>
>> of device,checking information regarding what is actually doing the
>> memory
>
>"of device, checking": missing space
>> and detecting possible error conditions.
>>
>
>Globally, I think you need to reword your commit message. IMHO, it is not
>clear though I think I've mostly understood what you meant reading the
>actual source code.
>
I am not a native English speaker, hopefully I can make big progress on writing.

>> Signed-off-by: beanhuo <beanhuo@...ron.com>
>> ---
>>  drivers/mtd/spi-nor/spi-nor.c | 19 +++++++++++++++++--
>>  include/linux/mtd/spi-nor.h   |  6 +++++-
>>  2 files changed, 22 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mtd/spi-nor/spi-nor.c
>> b/drivers/mtd/spi-nor/spi-nor.c index bc266f7..200e814 100644
>> --- a/drivers/mtd/spi-nor/spi-nor.c
>> +++ b/drivers/mtd/spi-nor/spi-nor.c
>> @@ -330,8 +330,23 @@ static inline int spi_nor_fsr_ready(struct spi_nor
>*nor)
>>  	int fsr = read_fsr(nor);
>>  	if (fsr < 0)
>>  		return fsr;
>> -	else
>> -		return fsr & FSR_READY;
>> +
>> +	if (fsr & (FSR_E_ERR | FSR_P_ERR)) {
>> +		if (fsr & FSR_E_ERR)
>> +			dev_err(nor->dev, "Erase operation failed.\n");
>> +		else
>> +			dev_err(nor->dev, "Program operation failed.\n");
>> +
>> +		if (fsr & FSR_PT_ERR)
>> +			dev_err(nor->dev,
>> +			"The operation has attempted to modify the
>protected"
>
>A space ' ' is missing after "protected".
>Also please verify next version passes the checkpatch test because this
>version doesn't.
>
Yes, I already re-sent this patch which merged these two line into one line.

>I think you should check the verb tense consistency:
>[...] operation failed. The operation attempted [...]
>
>Also maybe you should write "a protected sector" or "some protected sector":
>"the protected sector" sounds like there is only one protected sector.
>
>> +			"sector or the locked OPT space.\n");
>
>You meant OTP (One Time Programmable), didn't you ? s/OPT/OTP/
>

Yes, it is one time programmable space.

>> +
>> +		nor->write_reg(nor, SPINOR_OP_CLFSR, NULL, 0);
>> +		return -EIO;
>> +	}
>> +
>> +	return fsr & FSR_READY;
>>  }
>>
>>  static int spi_nor_ready(struct spi_nor *nor) diff --git
>> a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index
>> d0c66a0..46b5608 100644
>> --- a/include/linux/mtd/spi-nor.h
>> +++ b/include/linux/mtd/spi-nor.h
>> @@ -61,6 +61,7 @@
>>  #define SPINOR_OP_RDSFDP	0x5a	/* Read SFDP */
>>  #define SPINOR_OP_RDCR		0x35	/* Read configuration register
>*/
>>  #define SPINOR_OP_RDFSR		0x70	/* Read flag status register */
>> +#define SPINOR_OP_CLFSR		0x50	/* Clear flag status register */
>>
>>  /* 4-byte address opcodes - used on Spansion and some Macronix flashes.
>*/
>>  #define SPINOR_OP_READ_4B	0x13	/* Read data bytes (low
>frequency) */
>> @@ -130,7 +131,10 @@
>>  #define EVCR_QUAD_EN_MICRON	BIT(7)	/* Micron Quad I/O */
>>
>>  /* Flag Status Register bits */
>> -#define FSR_READY		BIT(7)
>> +#define FSR_READY		BIT(7)	/* Device status, 0 = Busy,1 = Ready */
>
>You may insert a space ' ' between "Busy," and "1 = "
>
I thought we care more on the code, rather than comment, thanks for reviewing.

>Best regards,
>
>Cyrille
>
>> +#define FSR_E_ERR		BIT(5)	/* Erase operation status */
>> +#define FSR_P_ERR		BIT(4)	/* Program operation status */
>> +#define FSR_PT_ERR		BIT(1)	/* Protection error bit */
>>
>>  /* Configuration Register bits. */
>>  #define CR_QUAD_EN_SPAN		BIT(1)	/* Spansion Quad I/O */
>>