Re: [EXT] Re: [PATCH 4/4] mtd: spinand: Add new Micron SPI NAND devices with multiple dies

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

Hi Shivamurthy,

"Shivamurthy Shastri (sshivamurthy)" <sshivamurthy@micron.com> wrote on
Tue, 21 Jan 2020 12:23:36 +0000:

> Hi Miquel,
> 
> > 
> > Hi Shiva,
> > 
> > shiva.linuxworks@gmail.com wrote on Sun, 19 Jan 2020 15:54:32 +0100:
> >   
> > > From: Shivamurthy Shastri <sshivamurthy@micron.com>
> > >
> > > Add device table for new Micron SPI NAND devices, which have multiple
> > > dies. While at it, add support to select the die.  
> > 
> > Same comment as in 3/4.  
> 
> I will correct the comment.

Actually now with more explanation I understand better. Please
keep in mind that anybody not knowing what you do on a daily basis
should understand what this commit does and why.

So like before, you actually don't need to split this patch, but
instead rework the commit message.

> 
> >   
> > >
> > > Signed-off-by: Shivamurthy Shastri <sshivamurthy@micron.com>
> > > ---
> > >  drivers/mtd/nand/spi/micron.c | 50  
> > +++++++++++++++++++++++++++++++++++  
> > >  1 file changed, 50 insertions(+)
> > >
> > > diff --git a/drivers/mtd/nand/spi/micron.c  
> > b/drivers/mtd/nand/spi/micron.c  
> > > index 45fc37c58f8a..03b486843210 100644
> > > --- a/drivers/mtd/nand/spi/micron.c
> > > +++ b/drivers/mtd/nand/spi/micron.c
> > > @@ -18,6 +18,8 @@
> > >  #define MICRON_STATUS_ECC_4TO6_BITFLIPS	(3 << 4)
> > >  #define MICRON_STATUS_ECC_7TO8_BITFLIPS	(5 << 4)
> > >
> > > +#define MICRON_DIE_SELECTION_BIT	6
> > > +
> > >  static SPINAND_OP_VARIANTS(read_cache_variants,
> > >  		SPINAND_PAGE_READ_FROM_CACHE_QUADIO_OP(0, 2,  
> > NULL, 0),  
> > >  		SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
> > > @@ -64,6 +66,21 @@ static const struct mtd_ooblayout_ops  
> > micron_8_ooblayout = {  
> > >  	.free = micron_8_ooblayout_free,
> > >  };
> > >
> > > +static int micron_select_target(struct spinand_device *spinand,
> > > +				unsigned int target)
> > > +{
> > > +	struct spi_mem_op op = SPINAND_SET_FEATURE_OP(0xd0,
> > > +						      spinand->scratchbuf);
> > > +
> > > +	/*
> > > +	 * As per datasheet, die selection is done by the 6th bit of Die
> > > +	 * Select Register (Address 0xD0).
> > > +	 */  
> > 
> > I would put this comment close to the macro definition.  
> 
> Sure, I will do it.
> 
> >   
> > > +	*spinand->scratchbuf = target << MICRON_DIE_SELECTION_BIT;  
> > 
> > Either target is or or 1 and you can use the BIT macro, or you suppose
> > it can go higher and the _BIT suffix does not fit. _SHIFT would work
> > and creating a macro directly would be even better.
> >   
> 
> I will create macro directly and send the code in next version.
> 
> > > +
> > > +	return spi_mem_exec_op(spinand->spimem, &op);
> > > +}
> > > +  
> > 
> > Where is this function used?  
> 
> IIUC your question, the function is used below in device table.
> The line is something like, 
> 
> SPINAND_SELECT_TARGET(micron_select_target))

I just missed it :)

> 
> for all the devices with multiple dies.
> 
> >   
> > >  static int micron_8_ecc_get_status(struct spinand_device *spinand,
> > >  				   u8 status)
> > >  {
> > > @@ -131,6 +148,17 @@ static const struct spinand_info  
> > micron_spinand_table[] = {  
> > >  		     0,
> > >  		     SPINAND_ECCINFO(&micron_8_ooblayout,
> > >  				     micron_8_ecc_get_status)),
> > > +	/* M79A 4Gb 3.3V */
> > > +	SPINAND_INFO("MT29F4G01ADAGD", 0x36,
> > > +		     NAND_MEMORG(1, 2048, 128, 64, 2048, 80, 2, 1, 2),
> > > +		     NAND_ECCREQ(8, 512),
> > > +		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
> > > +					      &write_cache_variants,
> > > +					      &update_cache_variants),
> > > +		     0,
> > > +		     SPINAND_ECCINFO(&micron_8_ooblayout,
> > > +				     micron_8_ecc_get_status),
> > > +		     SPINAND_SELECT_TARGET(micron_select_target)),
> > >  	/* M70A 4Gb 3.3V */
> > >  	SPINAND_INFO("MT29F4G01ABAFD", 0x34,
> > >  		     NAND_MEMORG(1, 4096, 256, 64, 2048, 40, 1, 1, 1),
> > > @@ -151,6 +179,28 @@ static const struct spinand_info  
> > micron_spinand_table[] = {  
> > >  		     0,
> > >  		     SPINAND_ECCINFO(&micron_8_ooblayout,
> > >  				     micron_8_ecc_get_status)),
> > > +	/* M70A 8Gb 3.3V */
> > > +	SPINAND_INFO("MT29F8G01ADAFD", 0x46,
> > > +		     NAND_MEMORG(1, 4096, 256, 64, 2048, 40, 1, 1, 2),
> > > +		     NAND_ECCREQ(8, 512),
> > > +		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
> > > +					      &write_cache_variants,
> > > +					      &update_cache_variants),
> > > +		     0,
> > > +		     SPINAND_ECCINFO(&micron_8_ooblayout,
> > > +				     micron_8_ecc_get_status),
> > > +		     SPINAND_SELECT_TARGET(micron_select_target)),
> > > +	/* M70A 8Gb 1.8V */
> > > +	SPINAND_INFO("MT29F8G01ADBFD", 0x47,
> > > +		     NAND_MEMORG(1, 4096, 256, 64, 2048, 40, 1, 1, 2),
> > > +		     NAND_ECCREQ(8, 512),
> > > +		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
> > > +					      &write_cache_variants,
> > > +					      &update_cache_variants),
> > > +		     0,
> > > +		     SPINAND_ECCINFO(&micron_8_ooblayout,
> > > +				     micron_8_ecc_get_status),
> > > +		     SPINAND_SELECT_TARGET(micron_select_target)),
> > >  };
> > >
> > >  static int micron_spinand_detect(struct spinand_device *spinand)  
> > 
> > 
> > 
> > 
> > Thanks,
> > Miquèl  
> 
> Thanks,
> Shiva




Thanks,
Miquèl

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