Re: [PATCH v6 1/4] mtd: spi-nor: macronix: add support for Macronix Octal

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Jaime,

You made a typo on Jagan's address, you might need to resend.

The title does not look correct, maybe you miss a word after Octal. And
is it something Macronix specific? I believe this is generic and you
can drop "Macronix" (the second occurrence) from the title.

jaimeliao.tw@gmail.com wrote on Wed, 29 Dec 2021 13:56:17 +0800:

> Follow patch "f6adec1af4b2f5d3012480c6cdce7743b74a6156" for adding

When pointing to an upstream commit I think even in U-Boot the style
should be something like:
<12-digit hash> ("title of the commit")
which at least allows to know which commit we are talking about.

> Macronix flash in Octal DTR mode.

This first part of the commit log should be moved below.

> 
> Enable Octal DTR mode with 20 dummy cycles to allow running at the
> maximum supported frequency.
>  -https://www.mxic.com.tw/Lists/Datasheet/Attachments/7841/MX25LM51245G,%203V,%20512Mb,%20v1.1.pdf
> 
> Signed-off-by: JaimeLiao <jaimeliao.tw@gmail.com>
> ---
>  drivers/mtd/spi/spi-nor-core.c | 83 ++++++++++++++++++++++++++++++++++
>  include/linux/mtd/spi-nor.h    | 12 ++++-
>  2 files changed, 93 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
> index d5d905fa5a..0a6550984b 100644
> --- a/drivers/mtd/spi/spi-nor-core.c
> +++ b/drivers/mtd/spi/spi-nor-core.c
> @@ -3489,6 +3489,85 @@ static struct spi_nor_fixups mt35xu512aba_fixups = {
>  };
>  #endif /* CONFIG_SPI_FLASH_MT35XU */
>  
> +#if CONFIG_IS_ENABLED(SPI_FLASH_MACRONIX)
> +/**
> + * spi_nor_macronix_octal_dtr_enable() - set DTR OPI Enable bit in Configuration Register 2.

This is very specific to Macronix I believe? Please just use a generic
description here.

> + * @nor:	pointer to a 'struct spi_nor'
> + *
> + * Set the DTR OPI Enable (DOPI) bit in Configuration Register 2.
> + * Bit 2 of  Configuration Register 2 is the DOPI bit for Macronix like OPI memories.
> + *
> + * Return: 0 on success, -errno otherwise.
> + */
> +static int spi_nor_macronix_octal_dtr_enable(struct spi_nor *nor)
> +{
> +	struct spi_mem_op op;
> +	int ret;
> +	u8 buf;
> +
> +	ret = write_enable(nor);
> +	if (ret)
> +		return ret;
> +
> +	buf = SPINOR_REG_MXIC_DC_20;
> +	op = (struct spi_mem_op)
> +		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_CR2, 1),
> +			   SPI_MEM_OP_ADDR(4, SPINOR_REG_MXIC_CR2_DC, 1),
> +			   SPI_MEM_OP_NO_DUMMY,
> +			   SPI_MEM_OP_DATA_OUT(1, &buf, 1));
> +
> +	ret = spi_mem_exec_op(nor->spi, &op);
> +	if (ret)
> +		return ret;
> +
> +	ret = spi_nor_wait_till_ready(nor);
> +	if (ret)
> +		return ret;
> +
> +	nor->read_dummy = MXIC_MAX_DC;
> +	ret = write_enable(nor);
> +	if (ret)
> +		return ret;
> +
> +	buf = SPINOR_REG_MXIC_OPI_DTR_EN;
> +	op = (struct spi_mem_op)
> +		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_WR_CR2, 1),
> +			   SPI_MEM_OP_ADDR(4, SPINOR_REG_MXIC_CR2_MODE, 1),
> +			   SPI_MEM_OP_NO_DUMMY,
> +			   SPI_MEM_OP_DATA_OUT(1, &buf, 1));
> +
> +	ret = spi_mem_exec_op(nor->spi, &op);
> +	if (ret) {
> +		dev_err(nor->dev, "Failed to enable octal DTR mode\n");
> +		return ret;
> +	}
> +	nor->reg_proto = SNOR_PROTO_8_8_8_DTR;
> +
> +	return 0;
> +}
> +
> +static void macronix_octal_default_init(struct spi_nor *nor)
> +{
> +	nor->octal_dtr_enable = spi_nor_macronix_octal_dtr_enable;
> +}
> +
> +static void macronix_octal_post_sfdp_fixup(struct spi_nor *nor,
> +					 struct spi_nor_flash_parameter *params)
> +{
> +	/*
> +	 * Adding SNOR_HWCAPS_PP_8_8_8_DTR in hwcaps.mask when
> +	 * SPI_NOR_OCTAL_DTR_READ flag exists.
> +	 */
> +	if (params->hwcaps.mask & SNOR_HWCAPS_READ_8_8_8_DTR)
> +		params->hwcaps.mask |= SNOR_HWCAPS_PP_8_8_8_DTR;
> +}
> +
> +static struct spi_nor_fixups macronix_octal_fixups = {
> +	.default_init = macronix_octal_default_init,
> +	.post_sfdp = macronix_octal_post_sfdp_fixup,
> +};
> +#endif /* CONFIG_SPI_FLASH_MACRONIX */
> +
>  /** spi_nor_octal_dtr_enable() - enable Octal DTR I/O if needed
>   * @nor:                 pointer to a 'struct spi_nor'
>   *
> @@ -3655,6 +3734,10 @@ void spi_nor_set_fixups(struct spi_nor *nor)
>  	if (!strcmp(nor->info->name, "mt35xu512aba"))
>  		nor->fixups = &mt35xu512aba_fixups;
>  #endif
> +
> +#if CONFIG_IS_ENABLED(SPI_FLASH_MACRONIX)
> +	nor->fixups = &macronix_octal_fixups;
> +#endif /* SPI_FLASH_MACRONIX */
>  }
>  
>  int spi_nor_scan(struct spi_nor *nor)
> diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> index 7ddc4ba2bf..8682368f2f 100644
> --- a/include/linux/mtd/spi-nor.h
> +++ b/include/linux/mtd/spi-nor.h
> @@ -116,8 +116,16 @@
>  #define XSR_RDY			BIT(7)	/* Ready */
>  
>  /* Used for Macronix and Winbond flashes. */
> -#define SPINOR_OP_EN4B		0xb7	/* Enter 4-byte mode */
> -#define SPINOR_OP_EX4B		0xe9	/* Exit 4-byte mode */
> +#define SPINOR_OP_EN4B			0xb7		/* Enter 4-byte mode */
> +#define SPINOR_OP_EX4B			0xe9		/* Exit 4-byte mode */
> +#define SPINOR_OP_RD_CR2		0x71		/* Read configuration register 2 */
> +#define SPINOR_OP_WR_CR2		0x72		/* Write configuration register 2 */
> +#define SPINOR_OP_MXIC_DTR_RD		0xee		/* Fast Read opcode in DTR mode */
> +#define SPINOR_REG_MXIC_CR2_MODE	0x00000000	/* For setting octal DTR mode */
> +#define SPINOR_REG_MXIC_OPI_DTR_EN	0x2		/* Enable Octal DTR */
> +#define SPINOR_REG_MXIC_CR2_DC		0x00000300	/* For setting dummy cycles */
> +#define SPINOR_REG_MXIC_DC_20		0x0		/* Setting dummy cycles to 20 */
> +#define MXIC_MAX_DC			20		/* Maximum value of dummy cycles */
>  
>  /* Used for Spansion flashes only. */
>  #define SPINOR_OP_BRWR		0x17	/* Bank register write */


Thanks,
Miquèl