From patchwork Tue Mar 7 15:32:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 660403 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54575C678D5 for ; Tue, 7 Mar 2023 15:33:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229868AbjCGPdI (ORCPT ); Tue, 7 Mar 2023 10:33:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59302 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231300AbjCGPdA (ORCPT ); Tue, 7 Mar 2023 10:33:00 -0500 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F6047C3EE for ; Tue, 7 Mar 2023 07:32:48 -0800 (PST) Received: by mail-pj1-x1035.google.com with SMTP id ce8-20020a17090aff0800b0023a61cff2c6so1812860pjb.0 for ; Tue, 07 Mar 2023 07:32:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1678203168; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=c3oD+VWh6vfXWKl1YinwYukVpyEX7O+ZCt88fiLI0g4=; b=RKiWq7kI7n6XmLArIWP1AnEyouczbA5z2QjZxwSdk9/YWDVGfDjQfkhiJtdsvXIhHZ 31v5iScnAoLMLvPeOkkr7apGnVHUR3f/0qXKPKEJr1wFwS3r/nEQ0mv/BloFixdhp1XV z+ULops+ColVZDGxpN+z2x9m6T0yFpAE42FHA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678203168; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=c3oD+VWh6vfXWKl1YinwYukVpyEX7O+ZCt88fiLI0g4=; b=LFqqWycdvPQWwjwZNwM9z5dts0ksiFNCvAtQOk9Nn90Ru8V2RsDDSHCj3bWoHrBo1z nn6EJNglCCqgIH69hejnf3D9/Mp4YTbKy6uIVPaMyb1nE9i9jiymudQWiEaSVmkmy5a2 mCpicD9Q60hNa7auIwxHYK1v3hdosArean3sGz+4j2e7dSieRj1ACrv1+G/vkJeWeJgQ aF+98V+PL6C96HdSOcUHpoQqltRhQ52LLBpBeDhtb7Nt8BlPxRxr9P6IFP5o2Uv75xWp XyZpHakODRhaIBEQXLT3NeKwJNzeakU7wndG7v5leSCB+OCMFShJ6atFOXU74aDu+a1R 9bYA== X-Gm-Message-State: AO0yUKV5dy0FvUN2MBYv3jefX5JAQL/fVlL9biXMef7TMxCMX2d/TtEi J4dRluxrQ4PAPMANfdbo9zwS1A== X-Google-Smtp-Source: AK7set+HF+uHK6o7uusM0NKP4C1wBRuoJGtW9phRDx4xNRHTf+wnthartYKd0Z8578jfS7OlD/PVxQ== X-Received: by 2002:a17:902:e748:b0:19e:82d5:634c with SMTP id p8-20020a170902e74800b0019e82d5634cmr16558648plf.53.1678203167946; Tue, 07 Mar 2023 07:32:47 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:2023:7dda:98bb:96dd]) by smtp.gmail.com with ESMTPSA id jy16-20020a17090342d000b0019719f752c5sm8586843plb.59.2023.03.07.07.32.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Mar 2023 07:32:47 -0800 (PST) From: Douglas Anderson To: Bjorn Andersson , Greg Kroah-Hartman Cc: Jiri Slaby , Bartosz Golaszewski , Daniel Thompson , linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, Konrad Dybcio , Douglas Anderson , Andy Gross , linux-kernel@vger.kernel.org Subject: [PATCH 1/3] tty: serial: qcom-geni-serial: Fix kdb/kgdb after port shutdown (again) Date: Tue, 7 Mar 2023 07:32:11 -0800 Message-Id: <20230307073155.1.Iaab0159b8d268060a0e131ebb27125af4750ef99@changeid> X-Mailer: git-send-email 2.40.0.rc0.216.gc4246ad0f0-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Commit d8aca2f96813 ("tty: serial: qcom-geni-serial: stop operations in progress at shutdown") was basically a straight revert of the commit it claims to fix without any explanation of why the problems talked about in the original patch were no longer relevant. Indeed, commit d8aca2f96813 ("tty: serial: qcom-geni-serial: stop operations in progress at shutdown") re-introduces the same problem that commit e83766334f96 ("tty: serial: qcom_geni_serial: No need to stop tx/rx on UART shutdown") fixed. The problems are very easy to see by simply doing this on a sc7180-based Chromebook: 1. Boot in developer mode with serial console enabled and kdb setup on the serial console. 2. via ssh: stop console-ttyMSM0; echo g > /proc/sysrq-trigger When you do the above you'll see the "kdb" prompt printed on the serial console but be unable to interact with it. Let's fix the problem again by noting that the console port is never configured in DMA mode and thus we don't need to stop things for the console. Fixes: d8aca2f96813 ("tty: serial: qcom-geni-serial: stop operations in progress at shutdown") Signed-off-by: Douglas Anderson Reviewed-by: Bartosz Golaszewski Reviewed-by: Johan Hovold --- drivers/tty/serial/qcom_geni_serial.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index d69592e5e2ec..74a0e074c2de 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1070,8 +1070,10 @@ static int setup_fifos(struct qcom_geni_serial_port *port) static void qcom_geni_serial_shutdown(struct uart_port *uport) { disable_irq(uport->irq); - qcom_geni_serial_stop_tx(uport); - qcom_geni_serial_stop_rx(uport); + if (!uart_console(uport)) { + qcom_geni_serial_stop_tx(uport); + qcom_geni_serial_stop_rx(uport); + } } static int qcom_geni_serial_port_setup(struct uart_port *uport) From patchwork Tue Mar 7 15:32:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 661546 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 373F2C6FD1A for ; Tue, 7 Mar 2023 15:33:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230405AbjCGPdM (ORCPT ); Tue, 7 Mar 2023 10:33:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231312AbjCGPdD (ORCPT ); Tue, 7 Mar 2023 10:33:03 -0500 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16CC07C96C for ; Tue, 7 Mar 2023 07:32:50 -0800 (PST) Received: by mail-pl1-x631.google.com with SMTP id n6so14493959plf.5 for ; Tue, 07 Mar 2023 07:32:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1678203169; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ON/hRDAPf2AptDjynSCH9JnA/LFyPWk7i2ryXctmn+Y=; b=k/thYJ/FejPWQY4Da3JnlIuxHSfFvf4jPgd0UIQ0b2XdTdjVTjlWvj9Vx0coE8ZGNf TSjcSYegW3Cq0PnDGKlL2Mfhd98ZxGSjG6XDb53DyE4nz6OldnbCqYZUKhF9YiHygxIC fnVimmDFtsACmxvO0ejshyH9K8EW9IuNupb40= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678203169; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ON/hRDAPf2AptDjynSCH9JnA/LFyPWk7i2ryXctmn+Y=; b=0IjmG2N+eWT+viSp7jVdxyGrwMugG1c+96BWGJaeQJH6mP5IxgyzIhIrj2E11z8cbN IzU6xzEtirvziFWsznhlBoB7Raajl7n0kKh/9mgWfVjxyiQTIFFZdn1BILyU4wlUkfSt 2CGzJhdnN0xbK5e97tCMOsVIhMz3gYwNQ1dznMWnCOxwMgR6CQ6zDRgBoTl/cUaPsVjQ F1ftImGAOb0JrHf8oZ/4H+yaLEyWxAOd04kaqRC4yzObwI+HOj8CnrXHv5rsTwJ0xkfP Ud6B/EtcThnzlgfeQplufeLxa+164psW+dTIcGGGLW7bWEif0EXvbWwPgfl9esNU+4sq 2asw== X-Gm-Message-State: AO0yUKXzDVyFoKQusAmgBgMfAsJdUJqiUWMBSjnV0KJTAeWvikkIC99c mhSMKlXb29foayN3xmGeHa4dKg== X-Google-Smtp-Source: AK7set8Pq0zKle5kvg0bl99RxErDbClwVzYTLcHrnnZKDUGJ1OcT5eP48PVWzvKPbEVb5LoqnGRxAA== X-Received: by 2002:a17:902:7798:b0:19c:bcb1:d8c3 with SMTP id o24-20020a170902779800b0019cbcb1d8c3mr12668737pll.54.1678203169556; Tue, 07 Mar 2023 07:32:49 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:2023:7dda:98bb:96dd]) by smtp.gmail.com with ESMTPSA id jy16-20020a17090342d000b0019719f752c5sm8586843plb.59.2023.03.07.07.32.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Mar 2023 07:32:49 -0800 (PST) From: Douglas Anderson To: Bjorn Andersson , Greg Kroah-Hartman Cc: Jiri Slaby , Bartosz Golaszewski , Daniel Thompson , linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, Konrad Dybcio , Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH 2/3] serial: uart_poll_init() should power on the UART Date: Tue, 7 Mar 2023 07:32:12 -0800 Message-Id: <20230307073155.2.I106c39498d8094c6f5e7ada42c7db17aa5c64e48@changeid> X-Mailer: git-send-email 2.40.0.rc0.216.gc4246ad0f0-goog In-Reply-To: <20230307073155.1.Iaab0159b8d268060a0e131ebb27125af4750ef99@changeid> References: <20230307073155.1.Iaab0159b8d268060a0e131ebb27125af4750ef99@changeid> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On Qualcomm devices which use the "geni" serial driver, kdb/kgdb won't be very happy if you use it but the resources of the port haven't been powered on. Today kdb/kgdb rely on someone else powering the port on. This could be the normal kernel console or an agetty running. Let's fix this to explicitly power things on when setting up a polling driver. Signed-off-by: Douglas Anderson --- drivers/tty/serial/serial_core.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 2bd32c8ece39..b14b5ed6fff4 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2593,6 +2593,7 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options) { struct uart_driver *drv = driver->driver_state; struct uart_state *state = drv->state + line; + enum uart_pm_state pm_state; struct tty_port *tport; struct uart_port *port; int baud = 9600; @@ -2610,6 +2611,9 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options) goto out; } + pm_state = state->pm_state; + uart_change_pm(state, UART_PM_STATE_ON); + if (port->ops->poll_init) { /* * We don't set initialized as we only initialized the hw, @@ -2626,6 +2630,8 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options) console_list_unlock(); } out: + if (ret) + uart_change_pm(state, pm_state); mutex_unlock(&tport->mutex); return ret; } From patchwork Tue Mar 7 15:32:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 660402 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F98FC678D5 for ; Tue, 7 Mar 2023 15:33:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231302AbjCGPd2 (ORCPT ); Tue, 7 Mar 2023 10:33:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59664 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231318AbjCGPdI (ORCPT ); Tue, 7 Mar 2023 10:33:08 -0500 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B88677E786 for ; 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Tue, 07 Mar 2023 07:32:51 -0800 (PST) Received: from tictac2.mtv.corp.google.com ([2620:15c:9d:2:2023:7dda:98bb:96dd]) by smtp.gmail.com with ESMTPSA id jy16-20020a17090342d000b0019719f752c5sm8586843plb.59.2023.03.07.07.32.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 07 Mar 2023 07:32:50 -0800 (PST) From: Douglas Anderson To: Bjorn Andersson , Greg Kroah-Hartman Cc: Jiri Slaby , Bartosz Golaszewski , Daniel Thompson , linux-serial@vger.kernel.org, linux-arm-msm@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, Konrad Dybcio , Douglas Anderson , Andy Gross , linux-kernel@vger.kernel.org Subject: [PATCH 3/3] tty: serial: qcom-geni-serial: Add a poll_init() function Date: Tue, 7 Mar 2023 07:32:13 -0800 Message-Id: <20230307073155.3.Ie678853bb101091afe78cc8c22344bf3ff3aed74@changeid> X-Mailer: git-send-email 2.40.0.rc0.216.gc4246ad0f0-goog In-Reply-To: <20230307073155.1.Iaab0159b8d268060a0e131ebb27125af4750ef99@changeid> References: <20230307073155.1.Iaab0159b8d268060a0e131ebb27125af4750ef99@changeid> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On sc7180 Chromebooks, I did the following: * Didn't enable earlycon in the kernel command line. * Didn't enable serial console in the kernel command line. * Didn't enable an agetty or any other client of "/dev/ttyMSM0". * Added "kgdboc=ttyMSM0" to the kernel command line. After I did that, I tried to enter kdb with this command over an ssh session: echo g > /proc/sysrq-trigger When I did that the system just hung. Although I thought I'd tested this scenario before, I couldn't go back and find a time when it was working. Previous testing must have relied on either the UART acting as the kernel console or an agetty running. It turns out to be pretty easy to fix: we can just use qcom_geni_serial_port_setup() as the .poll_init() function. This, together with the patch ("serial: uart_poll_init() should power on the UART"), allows the debugger to work even if there are no other users of the serial port. Signed-off-by: Douglas Anderson --- drivers/tty/serial/qcom_geni_serial.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 74a0e074c2de..00752ff783c6 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -1534,6 +1534,7 @@ static const struct uart_ops qcom_geni_console_pops = { #ifdef CONFIG_CONSOLE_POLL .poll_get_char = qcom_geni_serial_get_char, .poll_put_char = qcom_geni_serial_poll_put_char, + .poll_init = qcom_geni_serial_port_setup, #endif .pm = qcom_geni_serial_pm, };