From mboxrd@z Thu Jan 1 00:00:00 1970 From: t-kristo@ti.com (Tero Kristo) Date: Mon, 21 May 2012 12:11:40 +0300 Subject: [PATCHv2 10/19] ARM: OMAP4: PM: Work-around for ROM code BUG of IVAHD/TESLA In-Reply-To: <4FB43329.50505@ti.com> References: <1336990730-26892-1-git-send-email-t-kristo@ti.com> <1336990730-26892-11-git-send-email-t-kristo@ti.com> <87zk976827.fsf@ti.com> <4FB43329.50505@ti.com> Message-ID: <1337591500.28274.5.camel@sokoban> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, 2012-05-16 at 16:07 -0700, Kevin Hilman wrote: > On 05/16/2012 04:05 PM, Kevin Hilman wrote: > > Tero Kristo writes: > > > >> From: Santosh Shilimkar > >> > >> 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. > > Especially since this only effects a subset of revisions, installing the > notifier only on effected revisions also removes any overhead on working > revisions. Where would you recommend adding the notifiers to? Just to the same file or...? pm44xx.c? -Tero