From patchwork Thu Sep 19 23:36:44 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 276103 X-Patchwork-Delegate: sbabic@denx.de Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from theia.denx.de (theia.denx.de [85.214.87.163]) by ozlabs.org (Postfix) with ESMTP id 36A692C00DB for ; Fri, 20 Sep 2013 09:37:17 +1000 (EST) Received: from localhost (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id ACF5C4A13B; Fri, 20 Sep 2013 01:37:15 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at theia.denx.de Received: from theia.denx.de ([127.0.0.1]) by localhost (theia.denx.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XxEsGQtDH4ZO; Fri, 20 Sep 2013 01:37:15 +0200 (CEST) Received: from theia.denx.de (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id 1E2CD4A12F; Fri, 20 Sep 2013 01:37:11 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id BA3B04A12F for ; Fri, 20 Sep 2013 01:37:03 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at theia.denx.de Received: from theia.denx.de ([127.0.0.1]) by localhost (theia.denx.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id groOwoHHlkDN for ; Fri, 20 Sep 2013 01:36:56 +0200 (CEST) X-policyd-weight: NOT_IN_SBL_XBL_SPAMHAUS=-1.5 NOT_IN_SPAMCOP=-1.5 NOT_IN_BL_NJABL=-1.5 (only DNSBL check requested) Received: from mail-out.m-online.net (mail-out.m-online.net [212.18.0.10]) by theia.denx.de (Postfix) with ESMTPS id 898764A10F for ; Fri, 20 Sep 2013 01:36:49 +0200 (CEST) Received: from frontend1.mail.m-online.net (frontend1.mail.intern.m-online.net [192.168.8.180]) by mail-out.m-online.net (Postfix) with ESMTP id 3cgvbN4D6Fz3hjlK; Fri, 20 Sep 2013 01:36:48 +0200 (CEST) X-Auth-Info: 8KVYtGorP9qWIUHAajh+EvO0YYHCZJy3AteEiDgUXsY= Received: from chi.lan (unknown [195.140.253.167]) by smtp-auth.mnet-online.de (Postfix) with ESMTPA id 3cgvbN2Z6yzbbhf; Fri, 20 Sep 2013 01:36:48 +0200 (CEST) From: Marek Vasut To: u-boot@lists.denx.de Date: Fri, 20 Sep 2013 01:36:44 +0200 Message-Id: <1379633804-7751-1-git-send-email-marex@denx.de> X-Mailer: git-send-email 1.7.10.4 Cc: Marek Vasut , Fabio Estevam , Otavio Salvador Subject: [U-Boot] [PATCH] ARM: mxs: Setup stack in JTAG mode X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.11 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: u-boot-bounces@lists.denx.de Errors-To: u-boot-bounces@lists.denx.de In case the MX23/MX28 is switched into JTAG mode via the BootMode select switches, the BootROM bypasses the CPU core registers initialization. This in turn means that the Stack Pointer (SP) register is not set as it is in every other mode of operation, but instead is only zeroed out. To prevent U-Boot SPL from crashing in this obscure JTAG mode, configure the SP to point at the CONFIG_SYS_INIT_SP_ADDR if the SP is zeroed out. Note that in case the SP is already configured, we must preserve that exact SP value and must not modify it. This is important since in every other mode but the JTAG mode, the SPL returns into the BootROM and BootROM in turn loads U-Boot itself. If the SP were to be corrupted, the BootROM won't be able to continue it's operation after returned from SPL and the system would crash. Finally, add the JTAG mode switch identifier, so it's not recognised as Unknown mode. Signed-off-by: Marek Vasut Cc: Stefano Babic Cc: Fabio Estevam Cc: Otavio Salvador --- arch/arm/cpu/arm926ejs/mxs/start.S | 9 +++++++++ arch/arm/include/asm/arch-mxs/sys_proto.h | 2 ++ 2 files changed, 11 insertions(+) diff --git a/arch/arm/cpu/arm926ejs/mxs/start.S b/arch/arm/cpu/arm926ejs/mxs/start.S index 3e454ae..5de2bad 100644 --- a/arch/arm/cpu/arm926ejs/mxs/start.S +++ b/arch/arm/cpu/arm926ejs/mxs/start.S @@ -150,6 +150,15 @@ IRQ_STACK_START_IN: _reset: /* + * If the CPU is configured in "Wait JTAG connection mode", the stack + * pointer is not configured and is zero. This will cause crash when + * trying to push data onto stack right below here. Load the SP and make + * it point to the end of OCRAM if the SP is zero. + */ + cmp sp, #0x00000000 + ldreq sp, =CONFIG_SYS_INIT_SP_ADDR + + /* * Store all registers on old stack pointer, this will allow us later to * return to the BootROM and let the BootROM load U-Boot into RAM. * diff --git a/arch/arm/include/asm/arch-mxs/sys_proto.h b/arch/arm/include/asm/arch-mxs/sys_proto.h index 43c7dd6..09dfc90 100644 --- a/arch/arm/include/asm/arch-mxs/sys_proto.h +++ b/arch/arm/include/asm/arch-mxs/sys_proto.h @@ -46,6 +46,7 @@ static const struct mxs_pair mxs_boot_modes[] = { { 0x02, 0x1f, "SSP SPI #1, master, NOR" }, { 0x03, 0x1f, "SSP SPI #2, master, NOR" }, { 0x04, 0x1f, "NAND" }, + { 0x06, 0x1f, "JTAG" }, { 0x08, 0x1f, "SSP SPI #3, master, EEPROM" }, { 0x09, 0x1f, "SSP SD/MMC #0" }, { 0x0a, 0x1f, "SSP SD/MMC #1" }, @@ -60,6 +61,7 @@ static const struct mxs_pair mxs_boot_modes[] = { { 0x13, 0x1f, "SSP SPI #3, master, 1V8 NOR" }, { 0x04, 0x1f, "NAND, 3V3" }, { 0x14, 0x1f, "NAND, 1V8" }, + { 0x06, 0x1f, "JTAG" }, { 0x08, 0x1f, "SSP SPI #3, master, 3V3 EEPROM" }, { 0x18, 0x1f, "SSP SPI #3, master, 1V8 EEPROM" }, { 0x09, 0x1f, "SSP SD/MMC #0, 3V3" },