linux-kernel - RE: [PATCH v5 3/7] mtd: spi-nor: add opcodes for octal Read/Write commands

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Date:   Tue, 11 Dec 2018 04:55:29 +0000
From:   Yogesh Narayan Gaur <yogeshnarayan.gaur@....com>
To:     "Tudor.Ambarus@...rochip.com" <Tudor.Ambarus@...rochip.com>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        "boris.brezillon@...tlin.com" <boris.brezillon@...tlin.com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "marek.vasut@...il.com" <marek.vasut@...il.com>,
        "vigneshr@...com" <vigneshr@...com>,
        "linux-spi@...r.kernel.org" <linux-spi@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
CC:     "robh@...nel.org" <robh@...nel.org>,
        "mark.rutland@....com" <mark.rutland@....com>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "computersforpeace@...il.com" <computersforpeace@...il.com>,
        "frieder.schrempf@...eet.de" <frieder.schrempf@...eet.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH v5 3/7] mtd: spi-nor: add opcodes for octal Read/Write
 commands

Hi Tudor,

> -----Original Message-----
> From: Tudor.Ambarus@...rochip.com [mailto:Tudor.Ambarus@...rochip.com]
> Sent: Monday, December 10, 2018 4:15 PM
> To: Yogesh Narayan Gaur <yogeshnarayan.gaur@....com>; linux-
> mtd@...ts.infradead.org; boris.brezillon@...tlin.com; broonie@...nel.org;
> marek.vasut@...il.com; vigneshr@...com; linux-spi@...r.kernel.org;
> devicetree@...r.kernel.org
> Cc: robh@...nel.org; mark.rutland@....com; shawnguo@...nel.org; linux-
> arm-kernel@...ts.infradead.org; computersforpeace@...il.com;
> frieder.schrempf@...eet.de; linux-kernel@...r.kernel.org
> Subject: Re: [PATCH v5 3/7] mtd: spi-nor: add opcodes for octal Read/Write
> commands
> 
> Hi, Yogesh,
> 
> On 12/03/2018 10:39 AM, Yogesh Narayan Gaur wrote:
> > - Add opcodes for octal I/O commands
> >   * Read  : 1-1-8 and 1-8-8 protocol
> >   * Write : 1-1-8 and 1-8-8 protocol
> >   * opcodes for 4-byte address mode command
> >
> > - Entry of macros in _convert_3to4_xxx function
> >
> > - Add flag specifying flash support octal read commands.
> >
> > Signed-off-by: Vignesh R <vigneshr@...com>
> > Signed-off-by: Yogesh Gaur <yogeshnarayan.gaur@....com>
> > ---
> > Changes for v5:
> > - Modified string 'octo' with 'octal'.
> > Changes for v4:
> > - None
> > Changes for v3:
> > - Modified string 'octal' with 'octo'.
> > Changes for v2:
> > - Incorporated review comments of Boris and Vignesh
> >
> >  drivers/mtd/spi-nor/spi-nor.c | 16 ++++++++++++++--
> >  include/linux/mtd/spi-nor.h   |  8 ++++++++
> >  2 files changed, 22 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c
> > b/drivers/mtd/spi-nor/spi-nor.c index 398d273..7a2176d 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -90,6 +90,7 @@ struct flash_info {
> >  #define NO_CHIP_ERASE		BIT(12) /* Chip does not support chip
> erase */
> >  #define SPI_NOR_SKIP_SFDP	BIT(13)	/* Skip parsing of SFDP tables */
> >  #define USE_CLSR		BIT(14)	/* use CLSR command */
> > +#define SPI_NOR_OCTAL_READ	BIT(15)	/* Flash supports Octal Read */
> >
> >  	int	(*quad_enable)(struct spi_nor *nor);
> >  };
> > @@ -209,6 +210,8 @@ static inline u8 spi_nor_convert_3to4_read(u8 opcode)
> >  		{ SPINOR_OP_READ_1_2_2,	SPINOR_OP_READ_1_2_2_4B },
> >  		{ SPINOR_OP_READ_1_1_4,	SPINOR_OP_READ_1_1_4_4B },
> >  		{ SPINOR_OP_READ_1_4_4,	SPINOR_OP_READ_1_4_4_4B },
> > +		{ SPINOR_OP_READ_1_1_8,	SPINOR_OP_READ_1_1_8_4B },
> > +		{ SPINOR_OP_READ_1_8_8,	SPINOR_OP_READ_1_8_8_4B },
> >
> >  		{ SPINOR_OP_READ_1_1_1_DTR,
> 	SPINOR_OP_READ_1_1_1_DTR_4B },
> >  		{ SPINOR_OP_READ_1_2_2_DTR,
> 	SPINOR_OP_READ_1_2_2_DTR_4B },
> > @@ -225,6 +228,8 @@ static inline u8 spi_nor_convert_3to4_program(u8
> opcode)
> >  		{ SPINOR_OP_PP,		SPINOR_OP_PP_4B },
> >  		{ SPINOR_OP_PP_1_1_4,	SPINOR_OP_PP_1_1_4_4B },
> >  		{ SPINOR_OP_PP_1_4_4,	SPINOR_OP_PP_1_4_4_4B },
> > +		{ SPINOR_OP_PP_1_1_8,	SPINOR_OP_PP_1_1_8_4B },
> > +		{ SPINOR_OP_PP_1_8_8,	SPINOR_OP_PP_1_8_8_4B },
> >  	};
> >
> >  	return spi_nor_convert_opcode(opcode, spi_nor_3to4_program, @@
> > -2093,7 +2098,7 @@ enum spi_nor_read_command_index {
> >  	SNOR_CMD_READ_4_4_4,
> >  	SNOR_CMD_READ_1_4_4_DTR,
> >
> > -	/* Octo SPI */
> > +	/* Octal SPI */
> >  	SNOR_CMD_READ_1_1_8,
> >  	SNOR_CMD_READ_1_8_8,
> >  	SNOR_CMD_READ_8_8_8,
> > @@ -2110,7 +2115,7 @@ enum spi_nor_pp_command_index {
> >  	SNOR_CMD_PP_1_4_4,
> >  	SNOR_CMD_PP_4_4_4,
> >
> > -	/* Octo SPI */
> > +	/* Octal SPI */
> >  	SNOR_CMD_PP_1_1_8,
> >  	SNOR_CMD_PP_1_8_8,
> >  	SNOR_CMD_PP_8_8_8,
> > @@ -3195,6 +3200,13 @@ static int spi_nor_init_params(struct spi_nor *nor,
> >  					  SNOR_PROTO_1_1_4);
> >  	}
> >
> > +	if (info->flags & SPI_NOR_OCTAL_READ) {
> > +		params->hwcaps.mask |= SNOR_HWCAPS_READ_1_1_8;
> > +		spi_nor_set_read_settings(&params-
> >reads[SNOR_CMD_READ_1_1_8],
> > +					  0, 8, SPINOR_OP_READ_1_1_8,
> > +					  SNOR_PROTO_1_1_8);
> > +	}
> > +>  	/* Page Program settings. */
> >  	params->hwcaps.mask |= SNOR_HWCAPS_PP;
> >  	spi_nor_set_pp_settings(&params->page_programs[SNOR_CMD_PP],
> 
> At the end of spi_nor_init_params we check the conditions for parsing the sfdp.
> Shouldn't SPI_NOR_OCTAL_READ trigger the sfdp parsing when
> SPI_NOR_SKIP_SFDP is not set?

I guess for now setting only SPI_NOR_OCTAL_READ didn't trigger SFDP parsing as SFDP parsing would start only when we have both of the below condition are true
        if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ)) &&
            !(info->flags & SPI_NOR_SKIP_SFDP)) {
But for case when we have only set SPI_NOR_OCTAL_READ then first condition check would be false and hence SFDP parsing won't occur.

I guess, we needn't to have SFDP parsing only when SPI_NOR_SKIP_SFDP is set.
Thus would going to modify the condition check as below, so that SFDP parsing would also be performed when SPI_NOR_OCTAL_READ is set. Correct?

        if ((info->flags & (SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
             SPI_NOR_OCTAL_READ)) && !(info->flags & SPI_NOR_SKIP_SFDP)) {

--
Regards
Yogesh Gaur

> 
> > diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> > index 8b1acf6..019f534 100644
> > --- a/include/linux/mtd/spi-nor.h
> > +++ b/include/linux/mtd/spi-nor.h
> > @@ -50,9 +50,13 @@
> 
> Can you please s/octo/octal on these as well:
> $  grep -ni octo include/linux/mtd/spi-nor.h
> 471: * As a matter of performances, it is relevant to use Octo SPI protocols first,
> 492:#define SNOR_HWCPAS_READ_OCTO		GENMASK(14, 11)
> 501: * Like (Fast) Read capabilities, Octo/Quad SPI protocols are preferred to
> the
> 515:#define SNOR_HWCAPS_PP_OCTO	GENMASK(22, 20)
> 
> thanks,
> ta