From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@ti.com (Kevin Hilman) Date: Tue, 29 May 2012 13:13:18 -0700 Subject: [PATCHv2 10/19] ARM: OMAP4: PM: Work-around for ROM code BUG of IVAHD/TESLA In-Reply-To: <1337591500.28274.5.camel@sokoban> (Tero Kristo's message of "Mon, 21 May 2012 12:11:40 +0300") 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> <1337591500.28274.5.camel@sokoban> Message-ID: <87y5oag2zl.fsf@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Tero Kristo writes: > 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? Same file should be ok. Kevin