[U-Boot] [PATCH 0/2] Disable hybrid mode for SPANSION S25FS-S family

[Rajat Srivastava]

> -----Original Message-----
> From: Jagan Teki [mailto:jagannadh.teki at gmail.com]
> Sent: Tuesday, October 31, 2017 1:32 PM
> To: Rajat Srivastava <rajat.srivastava at nxp.com>
> Cc: u-boot at lists.denx.de; York Sun <york.sun at nxp.com>; Suresh Gupta
> <suresh.gupta at nxp.com>
> Subject: Re: [PATCH 0/2] Disable hybrid mode for SPANSION S25FS-S family
> 
> On Mon, Oct 30, 2017 at 5:23 PM, Rajat Srivastava <rajat.srivastava at nxp.com>
> wrote:
> >> On Mon, Oct 30, 2017 at 11:52 AM, Jagan Teki
> >> <jagannadh.teki at gmail.com>
> >> wrote:
> >> > On Mon, Oct 16, 2017 at 12:54 PM, Rajat Srivastava
> >> > <rajat.srivastava at nxp.com> wrote:
> >> >> The S25FS-S family physical sectors may be configured as a hybrid
> >> >> combination of eight 4-kB parameter sectors at the top or bottom
> >> >> of the address space with all but one of the remaining sectors
> >> >> being uniform size. The default status of the flash is the hybrid
> >> >> architecture.
> >> >>
> >> >> Since the parameter sectors and the uniform sectors have different
> >> >> erase commands, it is a problem to implement erase functionality
> >> >> for hybrid mode in current U-boot code. Also, enabling hybrid mode
> >> >> doesn't provide any significant benefit.
> >> >
> >> > I think I've asked this question before, keeping the state of the
> >> > flash remains same. Can't erase parameter and uniform sectors
> >> > individually during operations like
> >> > - parameter sectors with erase commands (20h or 21h)
> >> > - uniform sectors with erase commands (D8h or DCh)
> >>
> >> I understand that even we can do parameter and uniform sectors
> >> individually with the help of offsets we still have 224. Any idea why
> >> we need hybrid mode with this off 244 sector size? if require we can even
> write cypress on this case.
> >>
> > Hi Jagan
> >
> > I am not aware of usage of the remaining 244 sector area. We will discuss this
> with Cypress.
> >
> > Moreover, do you have any idea where we apply offset based checks in code?
> And if we do apply checks, will that look good with current Uboot code?
> > I think no one is going to use hybrid mode and even if someone wants to, they
> can modify the code.
> 
> We can change the erase opcode based on the offsets in erase ops, since if we
> disable hybrid now, if someone want to re-enable for another reason (say some
> kind of protection PB, not sure) will end-up conflict. Better we can ask Cypress
> about this and mean while we can post this change on spi-nor Linux for further
> discussion.
> 
Thanks Jagan. I am working on creating a similar patch in Linux.

Best regards
Rajat