From patchwork Mon Sep 24 21:27:54 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Vorontsov X-Patchwork-Id: 1500341 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 B0A8DDF280 for ; Mon, 24 Sep 2012 21:35:49 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TGGHb-0002zt-Tt; Mon, 24 Sep 2012 21:33:40 +0000 Received: from mail-pa0-f49.google.com ([209.85.220.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TGGGG-0002KZ-Fo for linux-arm-kernel@lists.infradead.org; Mon, 24 Sep 2012 21:32:18 +0000 Received: by padbi5 with SMTP id bi5so1755614pad.36 for ; Mon, 24 Sep 2012 14:32:15 -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=7KaA2BRdsMhQLsZvXE3qhH/QoxoadNucRNnpUWmxGO4=; b=WNfD1jHuF82iL65uscxgXEOVQohhvfxerdQHaftD+FluRfQ/TW9DA26nM6zfGUPlOk wKRJA/LSMSxUoOwBy6FJMUOdJRN7bRUiBY31XXjzMYUxNXEzIATVpzwjJPQhAnZenFv3 JHs09jVWUrkR2bO6aHEg3bGW6UUbWSKJkiShVo2oXSu8QjcgHDo0MW4gdL92AadBOuWh t9uUzqCVpIz/iynBJx1/1nVWWBAlct0tr5CPLmv+Ln8LzGpwmDg2e9OmUO2R0TwoIWzI OC6YOYTmifO3K6mLW3DcGWBPn18+WvaSjTwUqjd75GT606ntu3wghdIP1yquIH1BPMz6 kYAA== Received: by 10.68.200.227 with SMTP id jv3mr39957778pbc.162.1348522335567; Mon, 24 Sep 2012 14:32:15 -0700 (PDT) Received: from localhost (ip-64-134-232-154.public.wayport.net. [64.134.232.154]) by mx.google.com with ESMTPS id bn5sm9305196pab.12.2012.09.24.14.32.10 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 24 Sep 2012 14:32:14 -0700 (PDT) From: Anton Vorontsov To: Greg Kroah-Hartman , Russell King Subject: [PATCH 05/11] tty/serial/amba-pl011: Implement poll_init callback Date: Mon, 24 Sep 2012 14:27:54 -0700 Message-Id: <1348522080-32629-5-git-send-email-anton.vorontsov@linaro.org> X-Mailer: git-send-email 1.7.12 In-Reply-To: <20120924212648.GA27605@lizard> References: <20120924212648.GA27605@lizard> X-Gm-Message-State: ALoCoQmMDvqDuhcCmxqklMSpUu9ggvMPBI87SlLFrO9onr8sHpAv4WwcoF4YlZD0akh1a6vu7eeR 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 [209.85.220.49 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, Brian Swetland , Jason Wessel , linux-kernel@vger.kernel.org, =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= , John Stultz , linux-serial@vger.kernel.org, Colin Cross , kgdb-bugreport@lists.sourceforge.net, kernel-team@android.com, linux-arm-kernel@lists.infradead.org, Alan Cox 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 The callback is used to initialize the hardware, nothing else should be done, i.e. we should not request interrupts (but we can and do unmask some of them, as they might be useful for NMI entry). As a side-effect, the patch also fixes a division by zero[1] when booting with kgdboc options specified (e.g. kgdboc=ttyAMA0,115200n8). The issue happens because serial core calls set_termios callback, but the driver doesn't know clock frequency, and thus cannot calculate proper baud rate values. [1] WARNING: at drivers/tty/serial/serial_core.c:400 uart_get_baud_rate+0xe8/0x14c() Modules linked in: [] (unwind_backtrace+0x0/0xf0) from [] (warn_slowpath_common+0x4c/0x64) [] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_null+0x1c/0x24) [] (warn_slowpath_null+0x1c/0x24) from [] (uart_get_baud_rate+0xe8/0x14c) [] (uart_get_baud_rate+0xe8/0x14c) from [] (pl011_set_termios+0x48/0x278) [] (pl011_set_termios+0x48/0x278) from [] (uart_set_options+0xe8/0x114) [] (uart_set_options+0xe8/0x114) from [] (uart_poll_init+0xd4/0xe0) [] (uart_poll_init+0xd4/0xe0) from [] (tty_find_polling_driver+0x100/0x17c) [] (tty_find_polling_driver+0x100/0x17c) from [] (configure_kgdboc+0xc8/0x1b8) [] (configure_kgdboc+0xc8/0x1b8) from [] (do_one_initcall+0x30/0x168) [] (do_one_initcall+0x30/0x168) from [] (do_basic_setup+0x94/0xc8) [] (do_basic_setup+0x94/0xc8) from [] (kernel_init+0x60/0xf4) [] (kernel_init+0x60/0xf4) from [] (kernel_thread_exit+0x0/0x8) ---[ end trace 7d41c9186f342c40 ]--- Division by zero in kernel. [] (unwind_backtrace+0x0/0xf0) from [] (Ldiv0+0x8/0x10) [] (Ldiv0+0x8/0x10) from [] (pl011_set_termios+0x68/0x278) [] (pl011_set_termios+0x68/0x278) from [] (uart_set_options+0xe8/0x114) [] (uart_set_options+0xe8/0x114) from [] (uart_poll_init+0xd4/0xe0) [] (uart_poll_init+0xd4/0xe0) from [] (tty_find_polling_driver+0x100/0x17c) [] (tty_find_polling_driver+0x100/0x17c) from [] (configure_kgdboc+0xc8/0x1b8) [] (configure_kgdboc+0xc8/0x1b8) from [] (do_one_initcall+0x30/0x168) [] (do_one_initcall+0x30/0x168) from [] (do_basic_setup+0x94/0xc8) [] (do_basic_setup+0x94/0xc8) from [] (kernel_init+0x60/0xf4) [] (kernel_init+0x60/0xf4) from [] (kernel_thread_exit+0x0/0x8) Division by zero in kernel. [] (unwind_backtrace+0x0/0xf0) from [] (Ldiv0+0x8/0x10) [] (Ldiv0+0x8/0x10) from [] (uart_update_timeout+0x4c/0x5c) [] (uart_update_timeout+0x4c/0x5c) from [] (pl011_set_termios+0xc8/0x278) [] (pl011_set_termios+0xc8/0x278) from [] (uart_set_options+0xe8/0x114) [] (uart_set_options+0xe8/0x114) from [] (uart_poll_init+0xd4/0xe0) [] (uart_poll_init+0xd4/0xe0) from [] (tty_find_polling_driver+0x100/0x17c) [] (tty_find_polling_driver+0x100/0x17c) from [] (configure_kgdboc+0xc8/0x1b8) [] (configure_kgdboc+0xc8/0x1b8) from [] (do_one_initcall+0x30/0x168) [] (do_one_initcall+0x30/0x168) from [] (do_basic_setup+0x94/0xc8) [] (do_basic_setup+0x94/0xc8) from [] (kernel_init+0x60/0xf4) [] (kernel_init+0x60/0xf4) from [] (kernel_thread_exit+0x0/0x8) Signed-off-by: Anton Vorontsov Acked-by: Alan Cox --- drivers/tty/serial/amba-pl011.c | 44 ++++++++++++++++++++++++++++++----------- 1 file changed, 33 insertions(+), 11 deletions(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index cede938..45137e4 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1309,10 +1309,9 @@ static void pl011_put_poll_char(struct uart_port *port, #endif /* CONFIG_CONSOLE_POLL */ -static int pl011_startup(struct uart_port *port) +static int pl011_hwinit(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; - unsigned int cr; int retval; /* Optionaly enable pins to be muxed in and configured */ @@ -1337,6 +1336,37 @@ static int pl011_startup(struct uart_port *port) UART011_RTIS | UART011_RXIS, uap->port.membase + UART011_ICR); /* + * Save interrupts enable mask, and enable RX interrupts in case if + * the interrupt is used for NMI entry. + */ + uap->im = readw(uap->port.membase + UART011_IMSC); + writew(UART011_RTIM | UART011_RXIM, uap->port.membase + UART011_IMSC); + + if (uap->port.dev->platform_data) { + struct amba_pl011_data *plat; + + plat = uap->port.dev->platform_data; + if (plat->init) + plat->init(); + } + return 0; + out: + return retval; +} + +static int pl011_startup(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int cr; + int retval; + + retval = pl011_hwinit(port); + if (retval) + goto clk_dis; + + writew(uap->im, uap->port.membase + UART011_IMSC); + + /* * Allocate the IRQ */ retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap); @@ -1395,19 +1425,10 @@ static int pl011_startup(struct uart_port *port) writew(uap->im, uap->port.membase + UART011_IMSC); spin_unlock_irq(&uap->port.lock); - if (uap->port.dev->platform_data) { - struct amba_pl011_data *plat; - - plat = uap->port.dev->platform_data; - if (plat->init) - plat->init(); - } - return 0; clk_dis: clk_disable_unprepare(uap->clk); - out: return retval; } @@ -1688,6 +1709,7 @@ static struct uart_ops amba_pl011_pops = { .config_port = pl011_config_port, .verify_port = pl011_verify_port, #ifdef CONFIG_CONSOLE_POLL + .poll_init = pl011_hwinit, .poll_get_char = pl011_get_poll_char, .poll_put_char = pl011_put_poll_char, #endif