Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756850Ab0HaHI6 (ORCPT ); Tue, 31 Aug 2010 03:08:58 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:52590 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756326Ab0HaHI5 convert rfc822-to-8bit (ORCPT ); Tue, 31 Aug 2010 03:08:57 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=b0HxIXlLk71OYPV+acAmtpNScy+jPWkZI3IhuIW4fkTnW5Ob0hZHK/MzAoir+3jRK1 1vDCdLX97WzTfWK90z/scO6WnBUPAHkF4YuGflm33t82dVzhpg/KlxYjyR95GUMKHPnj c7Osc02ua4dUNxKEKVrK/MVeRd8rihl7r+wiw= MIME-Version: 1.0 In-Reply-To: References: <1282813649-8332-1-git-send-email-mark.brown314@gmail.com> <1282813649-8332-2-git-send-email-mark.brown314@gmail.com> From: Eric Miao Date: Tue, 31 Aug 2010 15:08:35 +0800 Message-ID: Subject: Re: [PATCH 1/1] ARM: pxa168: fix corrected reset vector To: Haojian Zhuang Cc: "Mark F. Brown" , Haojian Zhuang , linux-arm-kernel , linux-kernel Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5665 Lines: 140 On Tue, Aug 31, 2010 at 3:02 PM, Haojian Zhuang wrote: > On Tue, Aug 31, 2010 at 2:48 PM, Mark F. Brown wrote: >> On Tue, Aug 31, 2010 at 2:26 AM, Haojian Zhuang >> wrote: >>> On Tue, Aug 31, 2010 at 2:08 PM, Eric Miao wrote: >>>> On Tue, Aug 31, 2010 at 2:04 PM, Eric Miao wrote: >>>>> On Tue, Aug 31, 2010 at 2:02 PM, Mark F. Brown wrote: >>>>>> On Tue, Aug 31, 2010 at 1:48 AM, Eric Miao wrote: >>>>>>> On Thu, Aug 26, 2010 at 5:07 PM, Mark F. Brown wrote: >>>>>>>> Signed-off-by: Mark F. Brown >>>>>>>> --- >>>>>>>>  arch/arm/mach-mmp/include/mach/system.h |    2 +- >>>>>>>>  1 files changed, 1 insertions(+), 1 deletions(-) >>>>>>>> >>>>>>>> diff --git a/arch/arm/mach-mmp/include/mach/system.h b/arch/arm/mach-mmp/include/mach/system.h >>>>>>>> index 4f5b0e0..926e9c0 100644 >>>>>>>> --- a/arch/arm/mach-mmp/include/mach/system.h >>>>>>>> +++ b/arch/arm/mach-mmp/include/mach/system.h >>>>>>>> @@ -16,6 +16,6 @@ static inline void arch_idle(void) >>>>>>>> >>>>>>>>  static inline void arch_reset(char mode, const char *cmd) >>>>>>>>  { >>>>>>>> -       cpu_reset(0); >>>>>>>> +       cpu_reset(0xffff0000); >>>>>>> >>>>>>> Not sure if this correct. But normally reset jump happens after we turn >>>>>>> off the MMU and so on. Ain't the BootROM starts from 0 ? >>>>>>> >>>>>>>>  } >>>>>>>>  #endif /* __ASM_MACH_SYSTEM_H */ >>>>>>>> -- >>>>>>>> 1.7.0.4 >>>>>>>> >>>>>>>> >>>>>>> >>>>>> >>>>>> Eric, the boot-rom for pxa168 starts at 0xffff_0000. I am pretty sure >>>>>> about that! If you set the reset vector to 0x0 it will crash during >>>>>> reboot. I will send you xdb snapshots if you need me to. >>>>>> >>>>> >>>>> OK, you are expert on this :-) >>>>> >>>>> Applied to 'fix'. >>>>> >>>> >>>> One moment. Since this is really global to pxa910 and mmp2, so I >>>> suggest this being fixed for pxa168 only first. How about this: >>>> >>>>    ARM: pxa168: fix corrected reset vector >>>> >>>>    Reset vector for pxa168 is 0xffff_0000 not 0x0. This fix allows >>>>    reboot to work >>>> >>>>    Signed-off-by: Mark F. Brown >>>> >>>> diff --git a/arch/arm/mach-mmp/include/mach/system.h >>>> b/arch/arm/mach-mmp/include/mach/system.h >>>> index 4f5b0e0..1a8a25e 100644 >>>> --- a/arch/arm/mach-mmp/include/mach/system.h >>>> +++ b/arch/arm/mach-mmp/include/mach/system.h >>>> @@ -9,6 +9,8 @@ >>>>  #ifndef __ASM_MACH_SYSTEM_H >>>>  #define __ASM_MACH_SYSTEM_H >>>> >>>> +#include >>>> + >>>>  static inline void arch_idle(void) >>>>  { >>>>        cpu_do_idle(); >>>> @@ -16,6 +18,9 @@ static inline void arch_idle(void) >>>> >>>>  static inline void arch_reset(char mode, const char *cmd) >>>>  { >>>> -       cpu_reset(0); >>>> +       if (cpu_is_pxa168()) >>>> +               cpu_reset(0xffff0000); >>>> +       else >>>> +               cpu_reset(0); >>>>  } >>>>  #endif /* __ASM_MACH_SYSTEM_H */ >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >>>> the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html >>>> Please read the FAQ at  http://www.tux.org/lkml/ >>>> >>> The reset code is in below. >>> >>>        .align  5 >>> ENTRY(cpu_mohawk_reset) >>>        mov     ip, #0 >>>        mcr     p15, 0, ip, c7, c7, 0           @ invalidate I,D caches >>>        mcr     p15, 0, ip, c7, c10, 4          @ drain WB >>>        mcr     p15, 0, ip, c8, c7, 0           @ invalidate I & D TLBs >>>        mrc     p15, 0, ip, c1, c0, 0           @ ctrl register >>>        bic     ip, ip, #0x0007                 @ .............cam >>>        bic     ip, ip, #0x1100                 @ ...i...s........ >>>        mcr     p15, 0, ip, c1, c0, 0           @ ctrl register >>>        mov     pc, r0 >>> >>> MMU is disabled at here and replace PC with r0 value. I doubt code >>> executed correctly at here. While MMU is disabled, the PC should be >>> continue in the range of 0xCxxx_xxxx (kernel space). "mov pc, r0" >>> shouldn't be executed. Instruction fetch failure should occurs since >>> there's no physical address in 0xCxxx_xxxx. >>> >>> Correct me if I'm wrong. >>> >>> Thanks >>> Haojian >>> >> >> Haojian, >> >> I think there is a pipeline execution of the mov pc, r0 instruction. >> If I remember correctly you need to do a similar jump when you turn >> the MMU on in early boot code. If it makes any difference I did test >> this code on pxa168 before submitting it. I will double check the mmp2 >> and the pxa910 reset vectors with the Boot ROM developers. >> > > In early boot code, 1:1 (physical:virtual) mapping is used. It means > that physical address is same as virtual address. So you can operature > mmu as you wish. > > By the way, I don't suggest to reset CPU by this way. Reset is not > only make code running from the head, it should also clear registers > and RTL logic in CPU. > Depends on if pxa168 has a reset signal asserted from internal or from external GPIO, which is controllable from the CPU itself. That's what pxa is doing at this moment. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/