[U-Boot Patch v1 7/7] fu540: spi-nor: modify the flash read and program opcodes

[Sagar Kadam]

Hello Vignesh,

> -----Original Message-----
> From: Vignesh Raghavendra <vigneshr at ti.com>
> Sent: Friday, January 24, 2020 10:25 AM
> To: Sagar Kadam <sagar.kadam at sifive.com>; u-boot at lists.denx.de
> Cc: Paul Walmsley ( Sifive) <paul.walmsley at sifive.com>;
> anup.patel at wdc.com; ick at andestech.com; atish.patra at wdc.com;
> jagan at amarulasolutions.com
> Subject: Re: [U-Boot Patch v1 7/7] fu540: spi-nor: modify the flash read and
> program opcodes
> 
> 
> 
> On 24/01/20 1:46 am, Sagar Shrikant Kadam wrote:
> > This patch adds a workaround to change the read/write opcodes
> > from QUAD to single bit mode. Idea here is to enable usage of
> > spi-flash on the board.
> >
> > TODO:
> > -Enable QUAD mode for spi-flash on HiFive Unleashed A00 board.
> >
> > Signed-off-by: Sagar Shrikant Kadam <sagar.kadam at sifive.com>
> > ---
> >  drivers/mtd/spi/spi-nor-core.c | 15 ++++++++++++++-
> >  1 file changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
> > index c55116f..35d7772 100644
> > --- a/drivers/mtd/spi/spi-nor-core.c
> > +++ b/drivers/mtd/spi/spi-nor-core.c
> > @@ -295,7 +295,19 @@ static void spi_nor_set_4byte_opcodes(struct
> spi_nor *nor,
> >  		nor->erase_opcode = SPINOR_OP_SE;
> >  		nor->mtd.erasesize = info->sector_size;
> >  		break;
> > -
> > +#ifdef CONFIG_TARGET_SIFIVE_FU540
> > +	/*
> > +	 * This flash device does support QUAD bit mode. But
> > +	 * with tx-rx width specified to 4 bit mode in dt the spi
> > +	 * driver is unable to access flash device. TODO: Once basic
> > +	 * operational support is moved to mainline remove this
> workaround.
> > +	 */
> > +	case SNOR_MFR_ISSI:
> > +		nor->read_opcode = SPINOR_OP_READ_FAST;
> > +		nor->program_opcode = SPINOR_OP_PP;
> > +		break;
> > +#endif
> > +	default:
> 
> NACK.
> 
> Sorry, no Target specific #if'dery hacks in spi-nor-core please. Either
> debug and fix the issue or set tx-rx width to values that actually work
> in the mainline. You can switch tx-rx width to 4 when TODO is actually done.
> 

Ok, no problem.  So till TODO is actually done, I will modify the existing 
hifive-unleashed-a00.dts present in U-Boot and submit a V2 without these work-arounds.

Thanks & BR,
-Sagar

> >  		break;
> >  	}
> >
> > @@ -2636,6 +2648,7 @@ int spi_nor_scan(struct spi_nor *nor)
> >  		/* enable 4-byte addressing if the device exceeds 16MiB */
> >  		nor->addr_width = 4;
> >  		if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
> > +		    JEDEC_MFR(info) == SNOR_MFR_ISSI ||
> >  		    info->flags & SPI_NOR_4B_OPCODES)
> >  			spi_nor_set_4byte_opcodes(nor, info);
> >  #else
> >
> 
> --
> Regards
> Vignesh