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SubjectRe: [PATCH 07/13] mtd: spinand: Allow enabling Octal DTR mode in the core
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Hi Miquèl,

On 07/08/21 12:28 am, Miquel Raynal wrote:
> Hi Apurva,
>
> Apurva Nandan <a-nandan@ti.com> wrote on Tue, 13 Jul 2021 13:05:32
> +0000:
>
>> Enable Octal DTR SPI mode, i.e. 8D-8D-8D mode, if the SPI NAND flash
>> device supports it. Mixed OSPI (1S-1S-8S & 1S-8S-8S), mixed DTR modes
>> (1S-1D-8D), etc. aren't supported yet.
>>
>> The method to switch to Octal DTR SPI mode may vary across
>> manufacturers. For example, for Winbond, it is enabled by writing
>> values to the volatile configuration register. So, let the
>> manufacturer's code have their own implementation for switching to
>> Octal DTR SPI mode. Mixed OSPI (1S-1S-8S & 1S-8S-8S), mixed DTR modes
>> (1S-1D-8D), etc. aren't supported yet.
>
> You can drop the final sentence which is a repetition of the previous
> paragraph.
>

Yes right!

>> Check for the SPI NAND device's support for Octal DTR mode using
>> spinand flags, and if the op_templates allow 8D-8D-8D, call
> allows
>
>> octal_dtr_enable() manufacturer op. If the SPI controller doesn't
>> supports these modes, the selected op_templates would prevent switching
>
> will
>
>> to the Octal DTR mode. And finally update the spinand reg_proto
>> if success.
>
> on
>

Okay, will correct all!

>>
>> Signed-off-by: Apurva Nandan <a-nandan@ti.com>
>> ---
>> drivers/mtd/nand/spi/core.c | 46 +++++++++++++++++++++++++++++++++++++
>> include/linux/mtd/spinand.h | 3 +++
>> 2 files changed, 49 insertions(+)
>>
>> diff --git a/drivers/mtd/nand/spi/core.c b/drivers/mtd/nand/spi/core.c
>> index 1e619b6d777f..19d8affac058 100644
>> --- a/drivers/mtd/nand/spi/core.c
>> +++ b/drivers/mtd/nand/spi/core.c
>> @@ -256,6 +256,48 @@ static int spinand_init_quad_enable(struct spinand_device *spinand)
>> enable ? CFG_QUAD_ENABLE : 0);
>> }
>>
>> +static bool spinand_op_is_octal_dtr(const struct spi_mem_op *op)
>> +{
>> + return op->cmd.buswidth == 8 && op->cmd.dtr &&
>> + op->addr.buswidth == 8 && op->addr.dtr &&
>> + op->data.buswidth == 8 && op->data.dtr;
>> +}
>> +
>> +static int spinand_init_octal_dtr_enable(struct spinand_device *spinand)
>> +{
>> + struct device *dev = &spinand->spimem->spi->dev;
>> + int ret;
>> +
>> + if (!(spinand->flags & SPINAND_HAS_OCTAL_DTR_BIT))
>> + return 0;
>> +
>> + if (!(spinand_op_is_octal_dtr(spinand->op_templates.read_cache) &&
>> + spinand_op_is_octal_dtr(spinand->op_templates.write_cache) &&
>> + spinand_op_is_octal_dtr(spinand->op_templates.update_cache)))
>> + return 0;
>> +
>> + if (!spinand->manufacturer->ops->octal_dtr_enable) {
>> + dev_err(dev,
>> + "Missing ->octal_dtr_enable(), unable to switch mode\n");
>
> I don't think we want an error here. Perhaps a debug or info call, but
> no more.
>

Agree!

>> + return -EINVAL;
>> + }
>> +
>> + ret = spinand->manufacturer->ops->octal_dtr_enable(spinand);
>> + if (ret) {
>> + dev_err(dev,
>> + "Failed to enable Octal DTR SPI mode (err = %d)\n",
>> + ret);
>> + return ret;
>> + }
>> +
>> + spinand->reg_proto = SPINAND_OCTAL_DTR;
>> +
>> + dev_dbg(dev,
>> + "%s SPI NAND switched to Octal DTR SPI (8D-8D-8D) mode\n",
>> + spinand->manufacturer->name);
>> + return 0;
>> +}
>> +
>> static int spinand_ecc_enable(struct spinand_device *spinand,
>> bool enable)
>> {
>> @@ -1189,6 +1231,10 @@ static int spinand_init_flash(struct spinand_device *spinand)
>> if (ret)
>> return ret;
>>
>> + ret = spinand_init_octal_dtr_enable(spinand);
>> + if (ret)
>> + return ret;
>> +
>> ret = spinand_upd_cfg(spinand, CFG_OTP_ENABLE, 0);
>> if (ret)
>> return ret;
>> diff --git a/include/linux/mtd/spinand.h b/include/linux/mtd/spinand.h
>> index 35816b8cfe81..daa2ac5c3110 100644
>> --- a/include/linux/mtd/spinand.h
>> +++ b/include/linux/mtd/spinand.h
>> @@ -271,6 +271,7 @@ struct spinand_devid {
>> * @init: initialize a SPI NAND device
>> * @adjust_op: modify the ops for any variation in their cmd, address, dummy or
>> * data phase by the manufacturer
>> + * @octal_dtr_enable: switch the SPI NAND flash into Octal DTR SPI mode
>> * @cleanup: cleanup a SPI NAND device
>> *
>> * Each SPI NAND manufacturer driver should implement this interface so that
>> @@ -280,6 +281,7 @@ struct spinand_manufacturer_ops {
>> int (*init)(struct spinand_device *spinand);
>> void (*adjust_op)(struct spi_mem_op *op,
>> const enum spinand_proto reg_proto);
>> + int (*octal_dtr_enable)(struct spinand_device *spinand);
>> void (*cleanup)(struct spinand_device *spinand);
>> };
>>
>> @@ -348,6 +350,7 @@ struct spinand_ecc_info {
>>
>> #define SPINAND_HAS_QE_BIT BIT(0)
>> #define SPINAND_HAS_CR_FEAT_BIT BIT(1)
>> +#define SPINAND_HAS_OCTAL_DTR_BIT BIT(2)
>>
>> /**
>> * struct spinand_ondie_ecc_conf - private SPI-NAND on-die ECC engine structure
>
>
>
>
> Thanks,
> Miquèl
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>

Thanks,
Apurva Nandan

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