From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH 12/13] ARM: OMAP5: Add the build support Date: Tue, 8 May 2012 08:57:07 -0700 Message-ID: <20120508155706.GT5088@atomide.com> References: <1336029982-31898-1-git-send-email-r.sricharan@ti.com> <1336029982-31898-13-git-send-email-r.sricharan@ti.com> <20120504225857.GB5613@atomide.com> <20120507173749.GE5088@atomide.com> <4FA8E525.50506@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-01-ewr.mailhop.org ([204.13.248.71]:34321 "EHLO mho-01-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754876Ab2EHP5L (ORCPT ); Tue, 8 May 2012 11:57:11 -0400 Content-Disposition: inline In-Reply-To: <4FA8E525.50506@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Cousson, Benoit" Cc: "R, Sricharan" , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, santosh.shilimkar@ti.com * Cousson, Benoit [120508 02:23]: > Hi Tony, > > On 5/7/2012 7:37 PM, Tony Lindgren wrote: > >* R, Sricharan [120506 20:39]: > >>>>+config MACH_OMAP5_SEVM > >>>>+ bool "OMAP5 sevm Board" > >>>>+ depends on ARCH_OMAP5 > >>>>+ > >>>> config OMAP3_EMU > >>>> bool "OMAP3 debugging peripherals" > >>>> depends on ARCH_OMAP3 > >>> > >>>No need for it here either. Actually, I think this whole chunk > >>>can be now left out since it's DT based? > >>>he > >> ok, but the concern here was that without this macro > >> the print from compress and subsequently early > >>prints appear broken. > >> > >>machine_is_omap5_sevm becomes zero without this config and > >>machine_is_xxxx is used by the macro _DEBUG_LL_ENTRY > >>uncompress.h. > > > >Ah I see. > > Mmm, still, I guess this mechanism should be deprecated with DT? > We cannot keep creating fake board entry since we are not supposed > to have MACHINE_ID anymore. > That will break DEBUG_LL for sure, but we knew about that current > limitation with DT. For most usecases for DEBUG_LL we can get away in two steps: 1. Debug output for uncompress code based on DT parsing (I think this is already there) 2. Early console/earlyprintk parsed from DT that gets set up in init_early This should be enough for most users, then the people who need to debug early kernel code until init_early is done can patch it in manually. > The point is that we should fix the code to stop relying on a > machine id going forward. > And maybe we can parse the FDT at that time? Yes that should be trivial for most use cases, we just need to initialize the earlycon/earlyprintk based on the DT. See kernel/early_printk.c for more info. We just need to set up the hardware specific function for early_write instead of printch. Regards, Tony From mboxrd@z Thu Jan 1 00:00:00 1970 From: tony@atomide.com (Tony Lindgren) Date: Tue, 8 May 2012 08:57:07 -0700 Subject: [PATCH 12/13] ARM: OMAP5: Add the build support In-Reply-To: <4FA8E525.50506@ti.com> References: <1336029982-31898-1-git-send-email-r.sricharan@ti.com> <1336029982-31898-13-git-send-email-r.sricharan@ti.com> <20120504225857.GB5613@atomide.com> <20120507173749.GE5088@atomide.com> <4FA8E525.50506@ti.com> Message-ID: <20120508155706.GT5088@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Cousson, Benoit [120508 02:23]: > Hi Tony, > > On 5/7/2012 7:37 PM, Tony Lindgren wrote: > >* R, Sricharan [120506 20:39]: > >>>>+config MACH_OMAP5_SEVM > >>>>+ bool "OMAP5 sevm Board" > >>>>+ depends on ARCH_OMAP5 > >>>>+ > >>>> config OMAP3_EMU > >>>> bool "OMAP3 debugging peripherals" > >>>> depends on ARCH_OMAP3 > >>> > >>>No need for it here either. Actually, I think this whole chunk > >>>can be now left out since it's DT based? > >>>he > >> ok, but the concern here was that without this macro > >> the print from compress and subsequently early > >>prints appear broken. > >> > >>machine_is_omap5_sevm becomes zero without this config and > >>machine_is_xxxx is used by the macro _DEBUG_LL_ENTRY > >>uncompress.h. > > > >Ah I see. > > Mmm, still, I guess this mechanism should be deprecated with DT? > We cannot keep creating fake board entry since we are not supposed > to have MACHINE_ID anymore. > That will break DEBUG_LL for sure, but we knew about that current > limitation with DT. For most usecases for DEBUG_LL we can get away in two steps: 1. Debug output for uncompress code based on DT parsing (I think this is already there) 2. Early console/earlyprintk parsed from DT that gets set up in init_early This should be enough for most users, then the people who need to debug early kernel code until init_early is done can patch it in manually. > The point is that we should fix the code to stop relying on a > machine id going forward. > And maybe we can parse the FDT at that time? Yes that should be trivial for most use cases, we just need to initialize the earlycon/earlyprintk based on the DT. See kernel/early_printk.c for more info. We just need to set up the hardware specific function for early_write instead of printch. Regards, Tony