From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.semihalf.com (mail.semihalf.com [62.233.211.107]) by ozlabs.org (Postfix) with ESMTP id 34A3BDDEF0 for ; Sun, 1 Apr 2007 03:46:44 +1000 (EST) Message-ID: <460E9853.80902@semihalf.com> Date: Sat, 31 Mar 2007 19:20:19 +0200 From: Rafal Jaworowski MIME-Version: 1.0 To: Domen Puncer Subject: Re: [PATCH] icecube/lite5200b: wakeup from low-power support References: <20070315103959.GA22215@moe.telargo.com> <20070315104411.GF22215@moe.telargo.com> In-Reply-To: <20070315104411.GF22215@moe.telargo.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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: , 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, 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. 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? - 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) Also, a more general question: isn't time base update required after the wakeup, specially if it's been a long sleep? kind regards, Rafal