Subject: [PATCHv2 10/19] ARM: OMAP4: PM: Work-around for ROM code BUG of IVAHD/TESLA

From: [email-masked] (Kevin Hilman)
Date: Wed, 16 May 2012 16:05:20 -0700

Tero Kristo <[email-masked]> writes:

> From: Santosh Shilimkar <[email-masked]>
>
> The ROM BUG is when MPU Domain OFF wake up sequence that can compromise
> IVA and Tesla execution.
>
> At wakeup from MPU OFF on HS device only (not GP device), when
> restoring the Secure RAM, the ROM Code reconfigures the clocks the
> same way it is done at Cold Reset.

Ouch.

> The IVAHD Clocks and Power Domain settings are:
> 	IVAHD_CM2 IVAHD_CLKCTRL_MODULE_MODE = DISABLE
> 	IVAHD_CM2 SL2_CLKCTRL_MODULE_MODE = DISABLE
> 	IVAHD_CM2 SL2_CLKSTCTRL_CLKTRCTRL = HW_AUTO
> 	IVAHD_PRM IVAHD_PWRSTCTRL_POWERSTATE = OFF
> The TESLA Clocks and Power Domain settings are:
> 	TESLA_CM1 TESLA_CLKCTRL_MODULE_MODE = DISABLE
> 	TESLA_CM1 TESLA_CLKSTCTRL_CLKTRCTRL = HW_AUTO
> 	TESLA_PRM TESLA_PWRSTCTRL_POWERSTATE = OFF
>
> This patch fixes the low power OFF mode code so that the these
> registers are saved and restore across MPU OFF state.
>
> Also because of this limitation, MPU OFF alone is not targeted without
> device OFF to avoid IVAHD and TESLA execution impact

I don't see where this restriction is implemented.

And, can this be hooked into cluster PM notifiers.

Kevin