[U-Boot] hardware flash protect kept during a reboot?

[U-Boot] hardware flash protect kept during a reboot?

[Timur Tabi]

If I enable CONFIG_SYS_FLASH_PROTECTION and have a support flash chipset,
are my protected sectors supposed to remain protected during a reboot?

That is, if I protect some flash sector, and then reboot U-Boot, I know
U-Boot will not show the sector as being protected, because the
info->protect[] array is initialized on every boot.  However, since I was
using hardware protection, I expect the chip will still protect the sector.

-- 
Timur Tabi
Linux kernel developer at Freescale

[U-Boot] hardware flash protect kept during a reboot?

[Stefan Roese]

Hi Timur,

On Friday 14 May 2010 21:33:28 Timur Tabi wrote:
> If I enable CONFIG_SYS_FLASH_PROTECTION and have a support flash chipset,
> are my protected sectors supposed to remain protected during a reboot?
> 
> That is, if I protect some flash sector, and then reboot U-Boot, I know
> U-Boot will not show the sector as being protected, because the
> info->protect[] array is initialized on every boot.  However, since I was
> using hardware protection, I expect the chip will still protect the sector.

This protection is chip specific. IIRC, then some Intel (Strata) chips either 
protect all sectors or have a sectore-wise protection mechanism. You need to 
check your FLASH documentation for the exact behaviour. Which chip are you 
using?

Please note that we have the special "unlock" env variable. By setting it to 
"yes", all sectors will be unlocked upon startup. At least on Intel Strata 
FLASH chips.

Cheers,
Stefan

--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de

[U-Boot] hardware flash protect kept during a reboot?

[Timur Tabi]

Stefan Roese wrote:
> This protection is chip specific. IIRC, then some Intel (Strata) chips either 
> protect all sectors or have a sectore-wise protection mechanism. You need to 
> check your FLASH documentation for the exact behaviour. Which chip are you 
> using?

I just want to know whether hardware protection works at all for anyone
through a reboot.  Is the CFI "protect sector" command persistent through a
hardware power reset or power loss?

> Please note that we have the special "unlock" env variable. By setting it to 
> "yes", all sectors will be unlocked upon startup. At least on Intel Strata 
> FLASH chips.

I put a printf() in flash_real_protect(), so I know that's not the problem.

-- 
Timur Tabi
Linux kernel developer at Freescale

[U-Boot] hardware flash protect kept during a reboot?

[Stefan Roese]

On Monday 17 May 2010 16:11:22 Timur Tabi wrote:
> Stefan Roese wrote:
> > This protection is chip specific. IIRC, then some Intel (Strata) chips
> > either protect all sectors or have a sectore-wise protection mechanism.
> > You need to check your FLASH documentation for the exact behaviour.
> > Which chip are you using?
> 
> I just want to know whether hardware protection works at all for anyone
> through a reboot.  Is the CFI "protect sector" command persistent through a
> hardware power reset or power loss?

Yes. Its working at least for Intel Strata FLASH chips.

Cheers,
Stefan

--
DENX Software Engineering GmbH,      MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich,  Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-0 Fax: (+49)-8142-66989-80 Email: office at denx.de