From patchwork Mon Aug 20 14:47:22 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Vorontsov X-Patchwork-Id: 1349591 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork2.kernel.org (Postfix) with ESMTP id 3459BDFF0F for ; Mon, 20 Aug 2012 15:01:24 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1T3TJt-0002UC-2A; Mon, 20 Aug 2012 14:51:09 +0000 Received: from mail-pb0-f49.google.com ([209.85.160.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1T3TIu-00029E-FA for linux-arm-kernel@lists.infradead.org; Mon, 20 Aug 2012 14:50:09 +0000 Received: by pbbrq8 with SMTP id rq8so7544527pbb.36 for ; Mon, 20 Aug 2012 07:50:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references :x-gm-message-state; bh=UHQK30vZizGwnzAVRoEjF8rTm3DZJk8nIU/B02LymIU=; b=bVYo4CNvWbo++9WXz4uo8IakJOQoGmv44Y8wpxfF8IhNTGY3/4tJ11GVN5fTvWWtoW fc1OZHOzUKO1YpKzKrft3SyuOnhmn7Shp/SmLYu3qXhrC2Vfvd6ezJJsE4Y/aMNXuId6 p1yc3GPLuDoI3NIrGC6T121tyuVcBDoHOKETF+POlKNJhod8WRStCXXWOcVD0cwKBx3u oO5bfFLz2UDl4ehzgn/IR4tK+Ne2yPco2eHEIIMAeEGh0qkzwpW+soS8UyLTCr1PujEY sgb/XuVwo2+DLVvR6naQg2MvlJR5rS+RyFu3gPiyHKMGGH6QtaCGNwjswQK4t5gWdISn X6AQ== Received: by 10.66.76.227 with SMTP id n3mr30057991paw.53.1345474207442; Mon, 20 Aug 2012 07:50:07 -0700 (PDT) Received: from localhost (c-71-204-165-222.hsd1.ca.comcast.net. [71.204.165.222]) by mx.google.com with ESMTPS id gt2sm11221432pbc.62.2012.08.20.07.50.06 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 20 Aug 2012 07:50:07 -0700 (PDT) From: Anton Vorontsov To: Russell King , Jason Wessel , Greg Kroah-Hartman , Alan Cox Subject: [PATCH 04/12] tty/serial/core: Introduce poll_init callback Date: Mon, 20 Aug 2012 07:47:22 -0700 Message-Id: <1345474050-8339-4-git-send-email-anton.vorontsov@linaro.org> X-Mailer: git-send-email 1.7.11.5 In-Reply-To: <20120820144449.GA32560@lizard> References: <20120820144449.GA32560@lizard> X-Gm-Message-State: ALoCoQkKz2C8Tu3YIZrleAz7iikEq78BiaInyF2wN2o+GIp6Kv9IY+syLC3QObjmhQjSxT8t+7XR X-Spam-Note: CRM114 invocation failed X-Spam-Score: -2.6 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.6 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [209.85.160.49 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linaro-kernel@lists.linaro.org, patches@linaro.org, kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org, =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= , John Stultz , Colin Cross , kernel-team@android.com, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org It was noticed that polling drivers (like KGDB) are not able to use serial ports if the ports were not previously initialized via console. I.e. when booting with console=ttyAMA0 kgdboc=ttyAMA0, everything works fine, but with console=ttyFOO kgdboc=ttyAMA0, the kgdboc doesn't work. This is because we don't initialize the hardware. Calling ->startup() is not an option, because drivers request interrupts there, and drivers fail to handle situations when tty isn't opened with interrupts enabled. So, we have to implement a new callback (actually, tty_ops already have a similar callback), which does everything needed to initialize just the hardware. Signed-off-by: Anton Vorontsov --- drivers/tty/serial/serial_core.c | 15 +++++++++++++++ include/linux/serial_core.h | 1 + 2 files changed, 16 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index a21dc8e..cba8443 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2108,11 +2108,13 @@ 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; + struct tty_port *tport; struct uart_port *port; int baud = 9600; int bits = 8; int parity = 'n'; int flow = 'n'; + int ret; if (!state || !state->uart_port) return -1; @@ -2121,6 +2123,19 @@ static int uart_poll_init(struct tty_driver *driver, int line, char *options) if (!(port->ops->poll_get_char && port->ops->poll_put_char)) return -1; + tport = &state->port; + if (!(tport->flags & ASYNC_INITIALIZED) && port->ops->poll_init) { + mutex_lock(&tport->mutex); + ret = port->ops->poll_init(port); + /* + * We don't set ASYNCB_INITIALIZED as we only initialized the + * hw, e.g. state->xmit is still uninitialized. + */ + mutex_unlock(&tport->mutex); + if (ret) + return ret; + } + if (options) { uart_parse_options(options, &baud, &parity, &bits, &flow); return uart_set_options(port, NULL, baud, parity, bits, flow); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 0253c20..3642710 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -274,6 +274,7 @@ struct uart_ops { int (*verify_port)(struct uart_port *, struct serial_struct *); int (*ioctl)(struct uart_port *, unsigned int, unsigned long); #ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct uart_port *); void (*poll_put_char)(struct uart_port *, unsigned char); int (*poll_get_char)(struct uart_port *); #endif