From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B916C433E6 for ; Mon, 11 Jan 2021 15:18:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7655229CA for ; Mon, 11 Jan 2021 15:18:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732581AbhAKPR7 (ORCPT ); Mon, 11 Jan 2021 10:17:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729118AbhAKPR6 (ORCPT ); Mon, 11 Jan 2021 10:17:58 -0500 Received: from mail-wm1-x333.google.com (mail-wm1-x333.google.com [IPv6:2a00:1450:4864:20::333]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DAD7C061794 for ; Mon, 11 Jan 2021 07:17:18 -0800 (PST) Received: by mail-wm1-x333.google.com with SMTP id a6so162345wmc.2 for ; Mon, 11 Jan 2021 07:17:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=0TcPx+7pAz4mOWYUryj7o7tYaRTL8G4UVxUnW9m5I0k=; b=DEoO57eOc347UcLngC0mqGHqk13ZR+N6Vrv8iz9hXRyaMX1xMe+Cs1ifYqtzUA0nvd NQ57pZZKtYCU7ijRMRto7TtcU5RkH+RdDSjvymjocAbTyvIAHRGm14km6TRxdbqYIQAw NvQAY7kBorhPVZWQmSrYKWvUXbk5uBHNXBpjLW6OWPG/lj4zfAQwpxJYm4sow14P5lmJ uPRpj9aOo8/dLS75aaWftnEmBxt8tOgOJyB3By8UYlLYz4OIegliGMPaWvq+pMtZIt2T IPsphoISuAHVfmmRfpSDUQPQGfjXQ5EpClKGkjrsyFwCjKUd9egsvOUJwuR7O3l9l4D/ 4sNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=0TcPx+7pAz4mOWYUryj7o7tYaRTL8G4UVxUnW9m5I0k=; b=QHsshutn802NRKfBOYhfNeW8cboq62SdmB9GaBkvPEaIIIiPE6AZO/9WXkCMOBSKMq ymXuaJoogGFc4EkjTnpjJWXeqoGXGIKg4gMhXdwYO8UD5Bo/+B8V6rgPM1QMP8IekZjx Nie1HX/CY/2GxCxmCu+XilEkU71z9xIcBQXEizGTw0Ax99fmAsHzwMgZm0yqeU3757z9 0WQfoT1hGCZxIXXU4ftmNluV1ifSRigIoBu+mAKf9rPopQrSr7M9XWh+c0XVY/0K+pVW PfFh29WFnyPkL0uV3t2U81fq5WmoUaHxccbrfYX3xikf4WdZ3fJRd3O7nnsKKmwd9wDK 2f6g== X-Gm-Message-State: AOAM531F/tcXQ2wdmaizMBP68YzD+CcHHsU1QDetyZ8AbKGMVyfnQnzy wzxt5FelMgANrEWaMrw3vV8= X-Google-Smtp-Source: ABdhPJzw1xmUcOJ05wP+KGreicwg6Mno9pFPVs5TMOS191SkVsAXLEG9EhYrETFd4Xn1hNBtx1X5gA== X-Received: by 2002:a05:600c:2117:: with SMTP id u23mr145106wml.153.1610378237257; Mon, 11 Jan 2021 07:17:17 -0800 (PST) Received: from Saturn.local.all ([81.221.211.103]) by smtp.gmail.com with ESMTPSA id h5sm25549623wrp.56.2021.01.11.07.17.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Jan 2021 07:17:16 -0800 (PST) From: Max Krummenacher X-Google-Original-From: Max Krummenacher To: Max Krummenacher Cc: Max Krummenacher , Lucas Stach , linux-arm-kernel@lists.infradead.org, Fabio Estevam , Rouven Czerwinski , linux-kernel@vger.kernel.org, Ahmad Fatoum , Pengutronix Kernel Team , Sascha Hauer , Russell King , Shawn Guo , NXP Linux Team Subject: [PATCH 0/1] ARM: imx: build suspend-imx6.S with arm instruction set Date: Mon, 11 Jan 2021 16:17:03 +0100 Message-Id: <20210111151704.26296-1-max.krummenacher@toradex.com> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the kernel is configured to use the Thumb-2 instruction set "suspend-to-memory" fails to resume while in ARM mode it works as expected. (I used imx_v6_v7_defconfig and deselected ARCH_MULTI_V6 and selected THUMB2_KERNEL) The system prints what is expected when suspending but an event of a wakeup source does give no output. root@colibri-imx6ull:~# echo mem > /sys/power/state [ 58.610809] PM: suspend entry (deep) [ 58.629354] Filesystems sync: 0.014 seconds [ 58.653411] Freezing user space processes ... (elapsed 0.001 seconds) done. [ 58.661941] OOM killer disabled. [ 58.665176] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. [ 58.674028] printk: Suspending console(s) (use no_console_suspend to debug) -> trigger wakeup event, no reaction. It looks like the CPU resumes unconditionally in ARM instruction mode and then chokes on the presented Thumb-2 code it should execute on resume. With the following code change resume succeeds. --- a/arch/arm/mach-imx/suspend-imx6.S +++ b/arch/arm/mach-imx/suspend-imx6.S @@ -287,11 +286,20 @@ rbc_loop: bne rbc_loop /* Zzz, enter stop mode */ wfi +#ifdef CONFIG_THUMB2_KERNEL + /* i.MX CPUs seem to leave stop mode set to ARM instruction set */ + .arm +#endif nop nop nop nop +#ifdef CONFIG_THUMB2_KERNEL + /* switch to Thumb2 mode */ + sub pc, pc, #3 + .thumb +#endif /* I propose however to compile the whole file in ARM mode and have the linker taking care of the ARM/Thumb-2 switching. This would also keep the code working if a i.MX CPU variant exists that resumes in the same mode in which it went to sleep. Max Krummenacher (1): ARM: imx: build suspend-imx6.S with arm instruction set arch/arm/mach-imx/suspend-imx6.S | 1 + 1 file changed, 1 insertion(+) -- 2.26.2