From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from kukmak.uni-mb.si (kukmak.uni-mb.si [164.8.100.3]) by ozlabs.org (Postfix) with ESMTP id 067BBDDE29 for ; Sun, 1 Apr 2007 04:38:52 +1000 (EST) Date: Sat, 31 Mar 2007 20:38:44 +0200 From: Domen Puncer To: Rafal Jaworowski Subject: Re: [PATCH] icecube/lite5200b: wakeup from low-power support Message-ID: <20070331183843.GA3143@nd47.coderock.org> References: <20070315103959.GA22215@moe.telargo.com> <20070315104411.GF22215@moe.telargo.com> <460E9853.80902@semihalf.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <460E9853.80902@semihalf.com> Cc: u-boot-users@lists.sourceforge.net, linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 31/03/07 19:20 +0200, Rafal Jaworowski wrote: > Domen Puncer wrote: > >U-Boot part of Lite5200b low power mode support. > >Puts SDRAM out of self-refresh and transfers control to > >address saved at physical 0x0. > > > > Hi Domen, Hi! > > As I understand while waking up from the low-power mode the machine is > effectively powering on, similarly to the cold reset, so U-Boot runs > from the beginning as usual, but after the SDRAM controller has been > initialised we detect the wakeup and teleport to the saved DRAM address. Right. > > Since in case of a wakeup from the low-power mode we skip everything in > U-Boot that is happening past initdram(), please clarify the following: > > - are you sure there are no steps beyond init_func_ram()/board_init_f() > that should be performed while waking up? For example: > > - are all timers settings properly re-stored? Hmm... right, I forgot to restart watchdog... but that will be done in Linux code. > > - wouldn't the host/PCI bridge need to be re-initialised and > re-configured as part of the wakeup process? Did you happen to test some > PCI devices and would they survive after wakeup from the the low-power > mode? (A similar question would apply to the USB controller) Honestly, I don't know for PCI. IIRC some time ago, kernel compiled with CONFIG_PCI didn't boot for me. USB controller/devices survived the wakeup last time I checked. > > Also, a more general question: isn't time base update required after the > wakeup, specially if it's been a long sleep? Lite5200b doesn't have an external time source. Thanks! Domen From mboxrd@z Thu Jan 1 00:00:00 1970 From: Domen Puncer Date: Sat, 31 Mar 2007 20:38:43 +0200 Subject: [U-Boot-Users] [PATCH] icecube/lite5200b: wakeup from low-power support In-Reply-To: <460E9853.80902@semihalf.com> References: <20070315103959.GA22215@moe.telargo.com> <20070315104411.GF22215@moe.telargo.com> <460E9853.80902@semihalf.com> Message-ID: <20070331183843.GA3143@nd47.coderock.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de [ Gah, saw it didn't make it to u-boot ML, resending ] On 31/03/07 19:20 +0200, Rafal Jaworowski wrote: > Domen Puncer wrote: > >U-Boot part of Lite5200b low power mode support. > >Puts SDRAM out of self-refresh and transfers control to > >address saved at physical 0x0. > > > > Hi Domen, Hi! > > As I understand while waking up from the low-power mode the machine is > effectively powering on, similarly to the cold reset, so U-Boot runs > from the beginning as usual, but after the SDRAM controller has been > initialised we detect the wakeup and teleport to the saved DRAM address. Right. > > Since in case of a wakeup from the low-power mode we skip everything in > U-Boot that is happening past initdram(), please clarify the following: > > - are you sure there are no steps beyond init_func_ram()/board_init_f() > that should be performed while waking up? For example: > > - are all timers settings properly re-stored? Hmm... right, I forgot to restart watchdog... but that will be done in Linux code. > > - wouldn't the host/PCI bridge need to be re-initialised and > re-configured as part of the wakeup process? Did you happen to test some > PCI devices and would they survive after wakeup from the the low-power > mode? (A similar question would apply to the USB controller) Honestly, I don't know for PCI. IIRC some time ago, kernel compiled with CONFIG_PCI didn't boot for me. USB controller/devices survived the wakeup last time I checked. > > Also, a more general question: isn't time base update required after the > wakeup, specially if it's been a long sleep? Lite5200b doesn't have an external time source. Thanks! Domen