From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH PM-20081106] OMAP3: UART: Make sure that uart clocks are enabled when needed Date: Wed, 12 Nov 2008 09:20:55 -0800 Message-ID: <87skpwlv2g.fsf@deeprootsystems.com> References: <87od0ldw9c.fsf@trdhcp146196.ntc.nokia.com> <1226489259-1018-1-git-send-email-jouni.hogander@nokia.com> <8763mtm6j8.fsf@trdhcp146196.ntc.nokia.com> <8bf247760811120525y6130d4cdne70bfd1d999610e@mail.gmail.com> <871vxhm5iv.fsf@trdhcp146196.ntc.nokia.com> <8bf247760811120540k52fb6132u4b61e28407b799ec@mail.gmail.com> <8bf247760811120758m7d4ab607yde1288b053a7834f@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from ik-out-1112.google.com ([66.249.90.180]:55947 "EHLO ik-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751324AbYKLRVa convert rfc822-to-8bit (ORCPT ); Wed, 12 Nov 2008 12:21:30 -0500 Received: by ik-out-1112.google.com with SMTP id c29so441055ika.5 for ; Wed, 12 Nov 2008 09:21:28 -0800 (PST) In-Reply-To: <8bf247760811120758m7d4ab607yde1288b053a7834f@mail.gmail.com> (Sriram V.'s message of "Wed\, 12 Nov 2008 21\:28\:18 +0530") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Sriram V Cc: linux-omap@vger.kernel.org "Sriram V" writes: > Hi, > I just tried to find the source of the problem with PM-20081106 br= anch. > Am trying to debug this issue now. > > > I tried to do a check to find which commit caused the problem. > I find that it is something to do with uart pm support. > > > The patch commit 1e274e917472dba6c216b67c3afb3e7abe6e77e4 > OMAP3: PM: Allow UARTs to be unclocked when inactive > introduces this issue. > Sriram, Can you try Jouni's patch at the beginning of this thread on top of pm-20081106? Kevin > > > > > On Wed, Nov 12, 2008 at 7:10 PM, Sriram V wrote= : >> Hi jouni, >> I have disabled all the drivers except i2c and network also. >> i have applied your patch and still seeing problems. >> >> doing a echo mem > /sys/power/state makes the system to hang. >> >> does this work for you? >> >> >> Regards, >> sriram >> >> >> On Wed, Nov 12, 2008 at 7:05 PM, H=F6gander Jouni >> wrote: >>> "ext Sriram V" writes: >>> >>>> Hi jouni, >>>> Does the branch "PM-20081106" work for you? >>>> >>>> When i try to do a "echo mem > /sys/power/state" on omap3evm. >>>> >>>> the system hangs. Does Suspend-Resume work on this branch? >>> >>> Yes, but you need to apply this patch (or something similiar). Have >>> you done it and still seeing problems? >>> >>>> >>>> >>>> [root@OMAP3EVM /proc]# echo mem > /sys/power/state >>>> <6>PM: Syncing filesystems ... PM: Syncing filesystems ... done. >>>> done. >>>> Freezing user space processes ... Freezing user space processes ..= =2E >>>> (elapsed 0.00 seconds) (elapsed 0.00 seconds) done. >>>> done. >>>> Freezing remaining freezable tasks ... Freezing remaining freezabl= e >>>> tasks ... (elapsed 0.00 seconds) (elapsed 0.00 seconds) done.done. >>>> >>>> Suspending console(s) (use no_console_suspend to debug) >>>> Suspending console(s) (use no_console_suspend to debug) >>>> >>>> ---- system hangs---- >>>> >>>> >>>> With Regards, >>>> Sriram >>>> >>>> >>>> >>>> On Wed, Nov 12, 2008 at 6:43 PM, H=F6gander Jouni >>>> wrote: >>>>> "ext Jouni Hogander" writes: >>>>> >>>>>> Current implementation makes it possible that printouts are >>>>>> written into UART while its clocks are disabled. This causes fre= eze. >>>>> >>>>> Now I got how this new uart clock handling works. Event thought t= his >>>>> fix is not too sensible it actually does what is needed. >>>>> >>>>> So the problem is that uart clocks are enabled in prcm_interrupt.= Now >>>>> if some other interrupt handler is run before prcm_interrupt_hand= ler >>>>> and it tries to printout something to uart -> system freezes. >>>>> >>>>> Kevin, you should ensure some way that uart clocks are enabled ri= ght >>>>> away after wakeup. This patch presents one possibile >>>>> implementation. Another way could be to move uart_check_wakeup to= be >>>>> run in idle loop rather than in interrupt handler. >>>>> >>>>>> >>>>>> This patch contains possible fix for this. >>>>>> >>>>>> Signed-off-by: Jouni Hogander >>>>>> --- >>>>>> arch/arm/mach-omap2/pm34xx.c | 6 ++++++ >>>>>> arch/arm/mach-omap2/serial.c | 30 +++++++++++++++= +++++++++++++++ >>>>>> arch/arm/plat-omap/include/mach/serial.h | 2 ++ >>>>>> 3 files changed, 38 insertions(+), 0 deletions(-) >>>>>> >>>>>> diff --git a/arch/arm/mach-omap2/pm34xx.c b/arch/arm/mach-omap2/= pm34xx.c >>>>>> index d480c39..3838a19 100644 >>>>>> --- a/arch/arm/mach-omap2/pm34xx.c >>>>>> +++ b/arch/arm/mach-omap2/pm34xx.c >>>>>> @@ -320,6 +320,7 @@ void omap_sram_idle(void) >>>>>> /* PER */ >>>>>> per_next_state =3D pwrdm_read_next_pwrst(per_pwrdm); >>>>>> if (per_next_state < PWRDM_POWER_ON) { >>>>>> + omap_uart_prepare_idle(2); >>>>>> omap2_gpio_prepare_for_retention(); >>>>>> if (per_next_state =3D=3D PWRDM_POWER_OFF) >>>>>> omap3_per_save_context(); >>>>>> @@ -328,6 +329,8 @@ void omap_sram_idle(void) >>>>>> /* CORE */ >>>>>> core_next_state =3D pwrdm_read_next_pwrst(core_pwrdm); >>>>>> if (core_next_state < PWRDM_POWER_ON) { >>>>>> + omap_uart_prepare_idle(0); >>>>>> + omap_uart_prepare_idle(1); >>>>>> if (core_next_state =3D=3D PWRDM_POWER_OFF) { >>>>>> prm_set_mod_reg_bits(OMAP3430_AUTO_OFF, >>>>>> OMAP3430_GR_MOD, >>>>>> @@ -386,6 +389,8 @@ void omap_sram_idle(void) >>>>>> prm_clear_mod_reg_bits(OMAP3430_AUTO_OFF, >>>>>> OMAP3430_GR_MOD, >>>>>> OMAP3_PRM_VOLTCTRL_= OFFSET); >>>>>> + omap_uart_resume_idle(0); >>>>>> + omap_uart_resume_idle(1); >>>>>> } >>>>>> >>>>>> /* PER */ >>>>>> @@ -394,6 +399,7 @@ void omap_sram_idle(void) >>>>>> if (per_prev_state =3D=3D PWRDM_POWER_OFF) >>>>>> omap3_per_restore_context(); >>>>>> omap2_gpio_resume_after_retention(); >>>>>> + omap_uart_resume_idle(2); >>>>>> } >>>>>> >>>>>> /* Enable smartreflex after WFI */ >>>>>> diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/= serial.c >>>>>> index 65cce87..ef30d8d 100644 >>>>>> --- a/arch/arm/mach-omap2/serial.c >>>>>> +++ b/arch/arm/mach-omap2/serial.c >>>>>> @@ -249,6 +249,36 @@ static void omap_uart_idle_timer(unsigned l= ong data) >>>>>> omap_uart_allow_sleep(uart); >>>>>> } >>>>>> >>>>>> +void omap_uart_prepare_idle(int num) >>>>>> +{ >>>>>> + struct omap_uart_state *uart; >>>>>> + >>>>>> + if (!clocks_off_while_idle) >>>>>> + return; >>>>>> + >>>>>> + list_for_each_entry(uart, &uart_list, node) { >>>>>> + if (num =3D=3D uart->num && uart->can_sleep) { >>>>>> + omap_uart_disable_clocks(uart); >>>>>> + return; >>>>>> + } >>>>>> + } >>>>>> +} >>>>>> + >>>>>> +void omap_uart_resume_idle(int num) >>>>>> +{ >>>>>> + struct omap_uart_state *uart; >>>>>> + >>>>>> + if (!clocks_off_while_idle) >>>>>> + return; >>>>>> + >>>>>> + list_for_each_entry(uart, &uart_list, node) { >>>>>> + if (num =3D=3D uart->num) { >>>>>> + omap_uart_enable_clocks(uart); >>>>>> + return; >>>>>> + } >>>>>> + } >>>>>> +} >>>>>> + >>>>>> void omap_uart_check_wakeup(void) >>>>>> { >>>>>> struct omap_uart_state *uart; >>>>>> diff --git a/arch/arm/plat-omap/include/mach/serial.h b/arch/arm= /plat-omap/include/mach/serial.h >>>>>> index 11ff540..254a775 100644 >>>>>> --- a/arch/arm/plat-omap/include/mach/serial.h >>>>>> +++ b/arch/arm/plat-omap/include/mach/serial.h >>>>>> @@ -44,6 +44,8 @@ >>>>>> extern void omap_serial_init(void); >>>>>> extern int omap_uart_can_sleep(void); >>>>>> extern void omap_uart_check_wakeup(void); >>>>>> +extern void omap_uart_prepare_idle(int num); >>>>>> +extern void omap_uart_resume_idle(int num); >>>>>> #endif >>>>>> >>>>>> #endif >>>>>> -- >>>>>> 1.6.0.1 >>>>>> >>>>>> -- >>>>>> To unsubscribe from this list: send the line "unsubscribe linux-= omap" in >>>>>> the body of a message to majordomo@vger.kernel.org >>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.ht= ml >>>>> >>>>> -- >>>>> Jouni H=F6gander >>>>> >>>>> -- >>>>> To unsubscribe from this list: send the line "unsubscribe linux-o= map" in >>>>> the body of a message to majordomo@vger.kernel.org >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.htm= l >>>>> >>> >>> -- >>> Jouni H=F6gander >>> >>> >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-omap"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-omap" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html