From: Joseph Lo <josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> To: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Cc: "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" <linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>, Mike Turquette <mturquette-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Subject: Re: [PATCH 3/8] clk: tegra114: add LP1 suspend/resume support Date: Fri, 2 Aug 2013 16:09:45 +0800 [thread overview] Message-ID: <1375430985.6761.51.camel@jlo-ubuntu-64.nvidia.com> (raw) In-Reply-To: <51F6F209.2090309-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> On Tue, 2013-07-30 at 06:51 +0800, Stephen Warren wrote: > On 07/26/2013 03:15 AM, Joseph Lo wrote: > > When the system suspends to LP1, the clock of the CPU would be switched to > > CLK_M (12MHz Oscillator) during suspend/resume flow. The clock driver > > needs to restore the clock of CPU after LP1 resume. > > It's unclear to me how the code change implements "restore the clock of > the CPU". A register name of CCLKG_BURST_POLICY doesn't sound like it's > anything to do with enabled/disabling the CPU clock, nor configuring its > rate. What exactly does this register do, and hence what does this new > code actually restore? > When system suspend to LP1, most of the PLLs was clock gated. Because we didn't cut off the core power, the settings of PLL still keep there. But we switch the clock source of CPU to CLK_M before shut off PLLs by CCLKG_BURSY_POLICY register. So we need to resume it back to original clock source by CCLKG_BURST_POLICY register. Or it would be keep in low rate (CLK_M) after resume. > Why don't Tegra20/30 need a similar change? For Tegra20/30, the same code had been implemented in the suspend/resume function of tegra_cpu_car_ops. It restores the CPU clock ASAP when CPU resume from a suspend state to get quick performance I believe. For Tegra114, the resume performance is cool (although we can't see it in upstream kernel now, it still need some other functions.). We can implement all the clock related suspend/resume function in the clock driver.
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From: josephl@nvidia.com (Joseph Lo) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 3/8] clk: tegra114: add LP1 suspend/resume support Date: Fri, 2 Aug 2013 16:09:45 +0800 [thread overview] Message-ID: <1375430985.6761.51.camel@jlo-ubuntu-64.nvidia.com> (raw) In-Reply-To: <51F6F209.2090309@wwwdotorg.org> On Tue, 2013-07-30 at 06:51 +0800, Stephen Warren wrote: > On 07/26/2013 03:15 AM, Joseph Lo wrote: > > When the system suspends to LP1, the clock of the CPU would be switched to > > CLK_M (12MHz Oscillator) during suspend/resume flow. The clock driver > > needs to restore the clock of CPU after LP1 resume. > > It's unclear to me how the code change implements "restore the clock of > the CPU". A register name of CCLKG_BURST_POLICY doesn't sound like it's > anything to do with enabled/disabling the CPU clock, nor configuring its > rate. What exactly does this register do, and hence what does this new > code actually restore? > When system suspend to LP1, most of the PLLs was clock gated. Because we didn't cut off the core power, the settings of PLL still keep there. But we switch the clock source of CPU to CLK_M before shut off PLLs by CCLKG_BURSY_POLICY register. So we need to resume it back to original clock source by CCLKG_BURST_POLICY register. Or it would be keep in low rate (CLK_M) after resume. > Why don't Tegra20/30 need a similar change? For Tegra20/30, the same code had been implemented in the suspend/resume function of tegra_cpu_car_ops. It restores the CPU clock ASAP when CPU resume from a suspend state to get quick performance I believe. For Tegra114, the resume performance is cool (although we can't see it in upstream kernel now, it still need some other functions.). We can implement all the clock related suspend/resume function in the clock driver.
next prev parent reply other threads:[~2013-08-02 8:09 UTC|newest] Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-07-26 9:15 [PATCH 0/8] ARM: tegra: support LP1 suspend mode Joseph Lo 2013-07-26 9:15 ` Joseph Lo [not found] ` <1374830110-30685-1-git-send-email-josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> 2013-07-26 9:15 ` [PATCH 1/8] ARM: tegra: add common resume handling code for LP1 resuming Joseph Lo 2013-07-26 9:15 ` Joseph Lo [not found] ` <1374830110-30685-2-git-send-email-josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> 2013-07-29 22:38 ` Stephen Warren 2013-07-29 22:38 ` Stephen Warren 2013-07-26 9:15 ` [PATCH 2/8] ARM: tegra: config the polarity of the request of sys clock Joseph Lo 2013-07-26 9:15 ` Joseph Lo [not found] ` <1374830110-30685-3-git-send-email-josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> 2013-07-29 22:47 ` Stephen Warren 2013-07-29 22:47 ` Stephen Warren [not found] ` <51F6F109.8010102-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-02 7:48 ` Joseph Lo 2013-08-02 7:48 ` Joseph Lo [not found] ` <1375429739.6761.31.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> 2013-08-02 20:24 ` Stephen Warren 2013-08-02 20:24 ` Stephen Warren [not found] ` <51FC1579.50100-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-05 8:42 ` Joseph Lo 2013-08-05 8:42 ` Joseph Lo 2013-07-26 9:15 ` [PATCH 3/8] clk: tegra114: add LP1 suspend/resume support Joseph Lo 2013-07-26 9:15 ` Joseph Lo [not found] ` <1374830110-30685-4-git-send-email-josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> 2013-07-29 22:51 ` Stephen Warren 2013-07-29 22:51 ` Stephen Warren [not found] ` <51F6F209.2090309-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-02 8:09 ` Joseph Lo [this message] 2013-08-02 8:09 ` Joseph Lo [not found] ` <1375430985.6761.51.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> 2013-08-02 20:32 ` Stephen Warren 2013-08-02 20:32 ` Stephen Warren [not found] ` <51FC1751.9010401-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-05 8:02 ` Joseph Lo 2013-08-05 8:02 ` Joseph Lo [not found] ` <1375689749.1731.36.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> 2013-08-05 17:00 ` Stephen Warren 2013-08-05 17:00 ` Stephen Warren [not found] ` <51FFDA20.6050403-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-05 17:39 ` Stephen Warren 2013-08-05 17:39 ` Stephen Warren [not found] ` <51FFE363.4080603-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-06 9:10 ` Joseph Lo 2013-08-06 9:10 ` Joseph Lo [not found] ` <1375780249.2261.63.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> 2013-08-06 18:37 ` Stephen Warren 2013-08-06 18:37 ` Stephen Warren [not found] ` <52014258.9070602-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-07 9:12 ` Joseph Lo 2013-08-07 9:12 ` Joseph Lo [not found] ` <1375866749.8111.57.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> 2013-08-07 16:46 ` Stephen Warren 2013-08-07 16:46 ` Stephen Warren [not found] ` <520279FC.1000006-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-08 2:23 ` Joseph Lo 2013-08-08 2:23 ` Joseph Lo [not found] ` <1375928591.1758.66.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> 2013-08-08 19:54 ` Stephen Warren 2013-08-08 19:54 ` Stephen Warren [not found] ` <5203F766.9050100-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-09 9:23 ` Joseph Lo 2013-08-09 9:23 ` Joseph Lo 2013-08-06 9:19 ` Joseph Lo 2013-08-06 9:19 ` Joseph Lo 2013-07-26 9:15 ` [PATCH 4/8] ARM: tegra: add common LP1 suspend support Joseph Lo 2013-07-26 9:15 ` Joseph Lo [not found] ` <1374830110-30685-5-git-send-email-josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> 2013-07-29 23:13 ` Stephen Warren 2013-07-29 23:13 ` Stephen Warren [not found] ` <51F6F725.6000106-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-02 9:27 ` Joseph Lo 2013-08-02 9:27 ` Joseph Lo [not found] ` <1375435620.6761.120.camel-yx3yKKdKkHfc7b1ADBJPm0n48jw8i0AO@public.gmane.org> 2013-08-02 20:40 ` Stephen Warren 2013-08-02 20:40 ` Stephen Warren 2013-08-05 8:07 ` Joseph Lo 2013-08-05 8:07 ` Joseph Lo 2013-07-26 9:15 ` [PATCH 5/8] ARM: tegra30: add " Joseph Lo 2013-07-26 9:15 ` Joseph Lo [not found] ` <1374830110-30685-6-git-send-email-josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> 2013-07-29 23:45 ` Stephen Warren 2013-07-29 23:45 ` Stephen Warren [not found] ` <51F6FE89.4060402-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-05 6:46 ` Joseph Lo 2013-08-05 6:46 ` Joseph Lo 2013-07-26 9:15 ` [PATCH 6/8] ARM: tegra20: " Joseph Lo 2013-07-26 9:15 ` Joseph Lo 2013-07-26 9:15 ` [PATCH 7/8] ARM: tegra114: " Joseph Lo 2013-07-26 9:15 ` Joseph Lo [not found] ` <1374830110-30685-8-git-send-email-josephl-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> 2013-07-29 23:53 ` Stephen Warren 2013-07-29 23:53 ` Stephen Warren [not found] ` <51F7007F.6090200-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2013-08-05 6:51 ` Joseph Lo 2013-08-05 6:51 ` Joseph Lo 2013-07-26 9:15 ` [PATCH 8/8] ARM: dts: tegra: enable LP1 suspend mode Joseph Lo 2013-07-26 9:15 ` Joseph Lo 2013-07-27 16:12 ` [PATCH 0/8] ARM: tegra: support " Marc Dietrich 2013-07-27 16:12 ` Marc Dietrich 2013-07-27 16:20 ` Dmitry Osipenko 2013-07-27 16:20 ` Dmitry Osipenko [not found] ` <51F3F356.8080709-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> 2013-07-27 18:09 ` Marc Dietrich 2013-07-27 18:09 ` Marc Dietrich 2013-07-27 18:26 ` Dmitry Osipenko 2013-07-27 18:26 ` Dmitry Osipenko [not found] ` <51F410BE.3000904-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> 2013-07-27 18:29 ` Dmitry Osipenko 2013-07-27 18:29 ` Dmitry Osipenko 2013-07-27 19:03 ` Marc Dietrich 2013-07-27 19:03 ` Marc Dietrich 2013-07-27 19:11 ` Dmitry Osipenko 2013-07-27 19:11 ` Dmitry Osipenko 2013-07-30 9:49 ` Joseph Lo 2013-07-30 9:49 ` Joseph Lo
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