linux-kernel - Re: [PATCH v2] mtd: spinand: add SPI-NAND MTD resume handler

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Message-ID: <4ec0aea5-0a37-8575-e76d-02388b62efd9@foss.st.com>
Date:   Thu, 27 May 2021 15:11:27 +0200
From:   Patrice CHOTARD <patrice.chotard@...s.st.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
CC:     Mark Brown <broonie@...nel.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        <linux-mtd@...ts.infradead.org>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        <linux-spi@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <christophe.kerello@...s.st.com>
Subject: Re: [PATCH v2] mtd: spinand: add SPI-NAND MTD resume handler

Hi Miquel

On 5/27/21 10:53 AM, Miquel Raynal wrote:
> Hi Patrice,
> 
> <patrice.chotard@...s.st.com> wrote on Thu, 27 May 2021 10:49:59 +0200:
> 
>> From: Patrice Chotard <patrice.chotard@...s.st.com>
>>
>> After power up, all SPI NAND's blocks are locked. Only read operations
>> are allowed, write and erase operations are forbidden.
>> The SPI NAND framework unlocks all the blocks during its initialization.
>>
>> During a standby low power, the memory is powered down, losing its
>> configuration.
>> During the resume, the QSPI driver state is restored but the SPI NAND
>> framework does not reconfigured the memory.
>>
>> This patch adds SPI-NAND MTD PM handlers for resume ops.
>> SPI NAND resume op re-initializes SPI NAND flash to its probed state.
>>
>> It also adds a new helper spinand_block_unlock() which is
>> called in spinand_init() and in spinand_mtd_resume().
>>
>> Signed-off-by: Christophe Kerello <christophe.kerello@...s.st.com>
>> Signed-off-by: Patrice Chotard <patrice.chotard@...s.st.com>
>> ---
>> Changes in v2:
>>   - Add helper spinand_block_unlock().
>>   - Add spinand_ecc_enable() call.
>>   - Remove some dev_err().
>>   - Fix commit's title and message.
>>
>>  drivers/mtd/nand/spi/core.c | 62 +++++++++++++++++++++++++++++++------
>>  1 file changed, 53 insertions(+), 9 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
>> index 17f63f95f4a2..f77aeff11f43 100644
>> --- a/drivers/mtd/nand/spi/core.c
>> +++ b/drivers/mtd/nand/spi/core.c
>> @@ -1074,6 +1074,55 @@ static int spinand_detect(struct spinand_device *spinand)
>>  	return 0;
>>  }
>>  
>> +static int spinand_block_unlock(struct spinand_device *spinand)
>> +{
>> +	struct device *dev = &spinand->spimem->spi->dev;
>> +	struct nand_device *nand = spinand_to_nand(spinand);
>> +	int ret = 0, i;
>> +
>> +	for (i = 0; i < nand->memorg.ntargets; i++) {
>> +		ret = spinand_select_target(spinand, i);
>> +		if (ret)
>> +			return ret;
>> +
>> +		ret = spinand_lock_block(spinand, BL_ALL_UNLOCKED);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>> +	return ret;
>> +}
> 
> Please insert this helper (and use it in the probe) in a separate
> patch, so that patch 2/2 only implements the _resume hook.

ok

> 
>> +
>> +static void spinand_mtd_resume(struct mtd_info *mtd)
>> +{
>> +	struct spinand_device *spinand = mtd_to_spinand(mtd);
>> +	struct nand_device *nand = mtd_to_nanddev(mtd);
>> +	struct device *dev = &spinand->spimem->spi->dev;
>> +	int ret;
>> +
>> +	ret = spinand_reset_op(spinand);
>> +	if (ret)
>> +		return;
>> +
>> +	ret = spinand_init_quad_enable(spinand);
>> +	if (ret)
>> +		return;
>> +
>> +	ret = spinand_upd_cfg(spinand, CFG_OTP_ENABLE, 0);
>> +	if (ret)
>> +		return;
>> +
>> +	ret = spinand_manufacturer_init(spinand);
>> +	if (ret)
>> +		return;
>> +
>> +	ret = spinand_block_unlock(spinand);
>> +	if (ret)
>> +		return;
>> +
>> +	spinand_ecc_enable(spinand, false);
>> +}
>> +
>>  static int spinand_init(struct spinand_device *spinand)
>>  {
>>  	struct device *dev = &spinand->spimem->spi->dev;
>> @@ -1137,15 +1186,9 @@ static int spinand_init(struct spinand_device *spinand)
>>  	}
>>  
>>  	/* After power up, all blocks are locked, so unlock them here. */
>> -	for (i = 0; i < nand->memorg.ntargets; i++) {
>> -		ret = spinand_select_target(spinand, i);
>> -		if (ret)
>> -			goto err_manuf_cleanup;
>> -
>> -		ret = spinand_lock_block(spinand, BL_ALL_UNLOCKED);
>> -		if (ret)
>> -			goto err_manuf_cleanup;
>> -	}
>> +	ret = spinand_block_unlock(spinand);
>> +	if ret)
> 
> I doubt this as even be build-tested :)

I just noticed that the MTD_SPI_NAND kernel flag was disable :-( 
that's explain why i didn't see this compilation issue .... sorry

Thanks

> 
>> +		goto err_manuf_cleanup;
>>  
>>  	ret = nanddev_init(nand, &spinand_ops, THIS_MODULE);
>>  	if (ret)
>> @@ -1167,6 +1210,7 @@ static int spinand_init(struct spinand_device *spinand)
>>  	mtd->_block_isreserved = spinand_mtd_block_isreserved;
>>  	mtd->_erase = spinand_mtd_erase;
>>  	mtd->_max_bad_blocks = nanddev_mtd_max_bad_blocks;
>> +	mtd->_resume = spinand_mtd_resume;
>>  
>>  	if (nand->ecc.engine) {
>>  		ret = mtd_ooblayout_count_freebytes(mtd);
> 
> Thanks,
> Miquèl
>