From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753447Ab1ARU3L (ORCPT ); Tue, 18 Jan 2011 15:29:11 -0500 Received: from mail-qy0-f181.google.com ([209.85.216.181]:53031 "EHLO mail-qy0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753429Ab1ARU3I (ORCPT ); Tue, 18 Jan 2011 15:29:08 -0500 Subject: [PATCH 1/8] arm/dt: Make __vet_atags also accept a dtb image To: linux-arm-kernel@lists.infradead.org From: Grant Likely Cc: Nicolas Pitre , Russell King , Catalin Marinas , devicetree-discuss@lists.ozlabs.org, linux-kernel@vger.kernel.org, Olof Johansson , Jeremy Kerr , John Linn , Lennert Buijtenhek Date: Tue, 18 Jan 2011 13:29:02 -0700 Message-ID: <20110118202902.13011.68847.stgit@localhost6.localdomain6> In-Reply-To: <20110118195933.13011.56098.stgit@localhost6.localdomain6> References: <20110118195933.13011.56098.stgit@localhost6.localdomain6> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The dtb is passed to the kernel via register r2, which is the same method that is used to pass an atags pointer. This patch modifies __vet_atags to not clear r2 when it encounters a dtb image. Signed-off-by: Grant Likely --- arch/arm/kernel/head-common.S | 19 +++++++++++++------ arch/arm/kernel/head.S | 8 ++++---- 2 files changed, 17 insertions(+), 10 deletions(-) diff --git a/arch/arm/kernel/head-common.S b/arch/arm/kernel/head-common.S index 8f57515..d9a9105 100644 --- a/arch/arm/kernel/head-common.S +++ b/arch/arm/kernel/head-common.S @@ -14,6 +14,7 @@ #define ATAG_CORE 0x54410001 #define ATAG_CORE_SIZE ((2*4 + 3*4) >> 2) #define ATAG_CORE_SIZE_EMPTY ((2*4) >> 2) +#define OF_DT_MAGIC 0xedfe0dd0 /* 0xd00dfeed in big-endian */ /* * Exception handling. Something went wrong and we can't proceed. We @@ -105,22 +106,28 @@ __lookup_machine_type_data: /* Determine validity of the r2 atags pointer. The heuristic requires * that the pointer be aligned, in the first 16k of physical RAM and - * that the ATAG_CORE marker is first and present. Future revisions + * that the ATAG_CORE marker is first and present. If CONFIG_OF_FLATTREE + * is selected, then it will also accept a dtb pointer. Future revisions * of this function may be more lenient with the physical address and * may also be able to move the ATAGS block if necessary. * * r8 = machinfo * * Returns: - * r2 either valid atags pointer, or zero + * r2 either valid atags pointer, valid dtb pointer, or zero * r5, r6 corrupted */ __vet_atags: tst r2, #0x3 @ aligned? bne 1f - ldr r5, [r2, #0] @ is first tag ATAG_CORE? - cmp r5, #ATAG_CORE_SIZE +#ifdef CONFIG_OF_FLATTREE + ldr r5, [r2, #0] @ is it a DTB? + ldr r6, =OF_DT_MAGIC + cmp r5, r6 + beq 2f +#endif + cmp r5, #ATAG_CORE_SIZE @ is first tag ATAG_CORE? cmpne r5, #ATAG_CORE_SIZE_EMPTY bne 1f ldr r5, [r2, #4] @@ -128,7 +135,7 @@ __vet_atags: cmp r5, r6 bne 1f - mov pc, lr @ atag pointer is ok +2: mov pc, lr @ atag/dtb pointer is ok 1: mov r2, #0 mov pc, lr @@ -140,7 +147,7 @@ ENDPROC(__vet_atags) * * r0 = cp#15 control register * r1 = machine ID - * r2 = atags pointer + * r2 = atags/dtb pointer * r9 = processor ID */ __INIT diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index f17d9a0..65d9489 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -66,7 +66,7 @@ * * This is normally called from the decompressor code. The requirements * are: MMU = off, D-cache = off, I-cache = dont care, r0 = 0, - * r1 = machine nr, r2 = atags pointer. + * r1 = machine nr, r2 = atags or dtb pointer. * * This code is mostly position independent, so if you link the kernel at * 0xc0008000, you call this at __pa(0xc0008000). @@ -93,7 +93,7 @@ ENTRY(stext) beq __error_a @ yes, error 'a' /* - * r1 = machine no, r2 = atags, + * r1 = machine no, r2 = atags or dtb, * r8 = machinfo, r9 = cpuid, r10 = procinfo */ bl __vet_atags @@ -335,7 +335,7 @@ __secondary_data: * * r0 = cp#15 control register * r1 = machine ID - * r2 = atags pointer + * r2 = atags or dtb pointer * r4 = page table pointer * r9 = processor ID * r13 = *virtual* address to jump to upon completion @@ -372,7 +372,7 @@ ENDPROC(__enable_mmu) * * r0 = cp#15 control register * r1 = machine ID - * r2 = atags pointer + * r2 = atags or dtb pointer * r9 = processor ID * r13 = *virtual* address to jump to upon completion *