[PATCH 2/2] OMAP3: PM: Do not rely on ROM code to restore CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL

[Premi, Sanjeev]

> -----Original Message-----
> From: linux-omap-owner at vger.kernel.org 
> [mailto:linux-omap-owner at vger.kernel.org] On Behalf Of 
> Valentin, Eduardo
> Sent: Wednesday, April 13, 2011 8:51 PM
> To: Paul Walmsley; Kevin Hilman
> Cc: Linux-OMAP; Linux-ARM; Valentin, Eduardo
> Subject: [PATCH 2/2] OMAP3: PM: Do not rely on ROM code to 
> restore CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL
> 
> As per OMAP3 erratum (i671), ROM code adds extra latencies while
> restoring CM_AUTOIDLE_PLL register, if AUTO_PERIPH_DPLL is equal to 1.
> 
> This patch stores 0's in scratchpad content area corresponding to
> AUTO_PERIPH_DPLL, to prevent ROM code to try to lock per DPLL, since
> it won't respect proper programing scheme.
> 
> This register is then stored in prcm context. The saving and restore
> is now done by kernel side.
> 
> Here follow the erratum description
> 
> DESCRIPTION
> 
> After OFF mode transition, among many restorations, the ROM 
> Code restores the
> CM_AUTOIDLE_PLL register, and after that, it tries to relock 
> the PER DPLL.
> 
> In case the restoration data stored in scratchpad memory 
> contains a field
> CM_AUTOIDLE_PLL.AUTO_PERIPH_DPLL = 1, then the way the ROM 
> Code restores and
> locks the PER DPLL does not respect the PER DPLL programming scheme.
> 
> In that case, the DPLL might not lock. Meanwhile, when trying 
> to lock the PER
> DPLL, the ROM Code does not hang. Only extra latencies are 
> introduced at
> wake-up.
> 

[sp] You seem to have missed this patch:
http://marc.info/?l=linux-arm-kernel&m=129735383925285&w=2

~sanjeev