From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1O748X-0002bp-5X for barebox@lists.infradead.org; Wed, 28 Apr 2010 10:04:58 +0000 Date: Wed, 28 Apr 2010 12:04:55 +0200 From: Sascha Hauer Message-ID: <20100428100455.GF7634@pengutronix.de> References: <1272013443-29196-1-git-send-email-s.hauer@pengutronix.de> <1272013443-29196-11-git-send-email-s.hauer@pengutronix.de> <20100428023235.GF19722@game.jcrosoft.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20100428023235.GF19722@game.jcrosoft.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH 10/14] arm: reimplement startup code in C To: Jean-Christophe PLAGNIOL-VILLARD Cc: barebox@lists.infradead.org On Wed, Apr 28, 2010 at 04:32:35AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > On 11:03 Fri 23 Apr , Sascha Hauer wrote: > > Lets translate the startup code to a language we all understand better. > > Tested on pcm038 (arm v5) and pcm043 (arm v6). > > > > Signed-off-by: Sascha Hauer > > --- > > arch/arm/cpu/Makefile | 6 +- > > arch/arm/cpu/start-arm.S | 248 ------------------------------------ > > arch/arm/cpu/start.c | 107 ++++++++++++++++ > > arch/arm/include/asm/barebox-arm.h | 3 + > > arch/arm/lib/barebox.lds.S | 2 +- > > 5 files changed, 112 insertions(+), 254 deletions(-) > > delete mode 100644 arch/arm/cpu/start-arm.S > > create mode 100644 arch/arm/cpu/start.c > > > > diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile > > index ae1f762..036768e 100644 > > --- a/arch/arm/cpu/Makefile > > +++ b/arch/arm/cpu/Makefile > > @@ -1,15 +1,11 @@ > > obj-y += cpu.o > > obj-y += exceptions.o > > obj-y += interrupts.o > > +obj-y += start.o > > > > # > > # Any variants can be called as start-armxyz.S > > # > > -obj-$(CONFIG_CPU_ARM920T) += start-arm.o > > -obj-$(CONFIG_CPU_ARM926T) += start-arm.o > > -obj-$(CONFIG_CPU_V7) += start-arm.o > > -obj-$(CONFIG_ARCH_IMX31) += start-arm.o > > -obj-$(CONFIG_ARCH_IMX35) += start-arm.o > > obj-$(CONFIG_CMD_ARM_CPUINFO) += cpuinfo.o > > obj-$(CONFIG_MMU) += mmu.o > > obj-$(CONFIG_CPU_32v4T) += cache-armv4.o > > diff --git a/arch/arm/cpu/start-arm.S b/arch/arm/cpu/start-arm.S > > deleted file mode 100644 > > index 4d61cee..0000000 > > --- a/arch/arm/cpu/start-arm.S > > +++ /dev/null > > @@ -1,248 +0,0 @@ > > -/* > > + > > + /* disable MMU stuff and caches */ > > + __asm__ __volatile__("mrc p15, 0, %0, c1, c0, 0":"=r"(r)); > > + r &= ~0x2387; /* clear bits 13, 9:8, 7, 2:0 (--V- --RS B--- -CAM) */ > > + r |= 0x1002; /* set bit 2 (A) Align, set bit 12 (I) I-Cache */ > can we use here the CP15 macro > as CR_M and get_cr and set_cr? We don't have these macros now, eh wait, we do now ;) I'll send an update soon. > > + __asm__ __volatile__("mcr p15, 0, %0, c1, c0, 0" : : "r"(r)); > > + > > +#ifdef CONFIG_MACH_DO_LOWLEVEL_INIT > > + board_init_lowlevel(); > > +#endif > why not always avoid the ifdef CONFIG_ in the code and define an inline? Must think about it a bit further. But since this is the old behaviour lets just keep it for now, we can always change it later. > > + board_init_lowlevel_return(); > > +} > > + > otherwise it's really easier than the asm to maintain evenif I prefer to write > it in asm personnaly The original motivation was to get the pcm043 lowlevel setup smaller so that for Nand boot the initial code fits better into 2k of memory. I could have done some hand optimization in the assembler code, but that would have made it more unreadable. I didn't want to stop then... We can always look at the resulting disassembly if we want to. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox