linux-kernel - Re: [PATCH v3 3/3] mtd: spinand: add SPI-NAND MTD resume handler

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Message-ID: <1ed72554-311d-5f6f-a108-e29138166dc0@foss.st.com>
Date:   Fri, 28 May 2021 10:22:50 +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>,
        Pratyush Yadav <p.yadav@...com>
Subject: Re: [PATCH v3 3/3] mtd: spinand: add SPI-NAND MTD resume handler

Hi Miquel

On 5/27/21 6:23 PM, Miquel Raynal wrote:
> Hi Patrice,
> 
> + Pratyush
> 
> <patrice.chotard@...s.st.com> wrote on Thu, 27 May 2021 18:12:52 +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.
>>
>> Signed-off-by: Christophe Kerello <christophe.kerello@...s.st.com>
>> Signed-off-by: Patrice Chotard <patrice.chotard@...s.st.com>
>> ---
>> Changes in v3:
>>   - Add spinand_read_cfg() call to repopulate cache
>>
>> 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 | 33 +++++++++++++++++++++++++++++++++
>>  1 file changed, 33 insertions(+)
>>
>> diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
>> index 1f699ad84f1b..e3fcbcf381c3 100644
>> --- a/drivers/mtd/nand/spi/core.c
>> +++ b/drivers/mtd/nand/spi/core.c
>> @@ -1099,6 +1099,38 @@ static int spinand_block_unlock(struct spinand_device *spinand)
>>  	return ret;
>>  }
>>  
>> +static void spinand_mtd_resume(struct mtd_info *mtd)
>> +{
>> +	struct spinand_device *spinand = mtd_to_spinand(mtd);
>> +	int ret;
>> +
>> +	ret = spinand_reset_op(spinand);
>> +	if (ret)
>> +		return;
>> +
>> +	ret = spinand_read_cfg(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);
>> +}
> 
> Sorry for not being clear, but I think what Pratyush meant was that
> you could create a helper doing all the common initializations between
> spinand_init() and spinand_resume() and call it from these places to
> avoid code duplication. His comment somehow outclassed mine as I only
> focused on the unlock part (which I think is clearer anyway, please keep
> it like that).
> 

My bad too, i read too quickly Pratyush's asnwer.
I am preparing a v4.

Thanks
Patrice


>> +
>>  static int spinand_init(struct spinand_device *spinand)
>>  {
>>  	struct device *dev = &spinand->spimem->spi->dev;
>> @@ -1186,6 +1218,7 @@ 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
>