[U-Boot] [PATCHv3] mtd: sf: Add CONFIG_SPI_N25Q256A_RESET for software-reset

[Pavel Machek <pavel@denx.de>]

On Fri 2015-05-15 11:36:11, Marek Vasut wrote:
> On Friday, May 15, 2015 at 10:47:46 AM, Pavel Machek wrote:
> > > >> Seems like nothing much doing in micron side
> > > >> 
> > > >>         switch (JEDEC_MFR(info)) {
> > > >>         case CFI_MFR_ST: /* Micron, actually */
> > > >>         
> > > >>                 /* Some Micron need WREN command; all will accept it
> > > >>                 */ need_wren = true;
> > > > 
> > > > Umm. Take a closer look.
> > > > 
> > > > There's no break, so it continues below.
> > > 
> > > Ohh.. So Linux works for you.. then is it?
> > 
> > Well, yes, but this code patch is actually not tested in my case,
> > because u-boot already resets it for Linux.
> > 
> > Anyway, is this what you'd like to see?
> 
> Was my idea of checking in which mode the SPI NOR is first discarded ?

Yes, better just reset it.

> [...]
> 
> > @@ -233,6 +234,30 @@ static int spi_flash_validate_params(struct spi_slave
> > *spi, u8 *idcode, flash->poll_cmd = CMD_FLAG_STATUS;
> >  #endif
> > 
> > +	if (params->flags & MICRON_RESET) {
> > +#define CMD_RESET_ENABLE 0x66
> > +#define CMD_RESET_MEMORY 0x99
> > +	  int ret;
> 
> The indent here seems funny.
> 
> I think it'd be better to pull this reset procedure into a separate
> function.

Can do, but I need to know if this is what Jagan wanted, first.
									Pavel

> > +		/*
> > +		 * This is needed for the SoCFPGA booting from SPI NOR flash
> > +		 * e.g. (N25Q256A), as U-Boot SPL 2013-socfpga (only version
> > +		 * working on that board) sets 4-byte addressing mode.
> > +		 */
> > +		ret = spi_flash_cmd(spi, CMD_RESET_ENABLE, NULL, 0);
> > +		if (ret) {
> > +			printf("SF: Failed issue enable reset command\n");
> > +			return ret;
> > +		}
> > +
> > +		ret = spi_flash_cmd(spi, CMD_RESET_MEMORY, NULL, 0);
> > +		if (ret) {
> > +			printf("SF: Failed issue reset command\n");
> > +			return ret;
> > +		}
> > +
> > +		printf("SF: Device software reset\n");
> > +	}
> 
> Otherwise I think it's OK.

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