From patchwork Tue Sep 11 09:34:59 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Vorontsov X-Patchwork-Id: 1436391 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id CA0913FC33 for ; Tue, 11 Sep 2012 09:43:09 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TBMwA-0003mg-Oz; Tue, 11 Sep 2012 09:39:19 +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 1TBMv6-0003R4-6J for linux-arm-kernel@lists.infradead.org; Tue, 11 Sep 2012 09:38:14 +0000 Received: by mail-pb0-f49.google.com with SMTP id rq8so569866pbb.36 for ; Tue, 11 Sep 2012 02:38:11 -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=aRw53y2DUQLq/WEZhkmOxrqPdPGN+BPYpiTzzYFcSCE=; b=bf8J8nZFVSY2X8SYsMhtVksmKcpQg0oMwxKl4t4mOCWfiEC9pi961n9ythYCmSxc8q kV8QKmEsG4S8Ag5t+c6L1GvzttsHtfcOOOtrYZZWYSxOOD3I5bRWGXheUtdCbgn87WER oxaYnVe0VKqTU3KGBoXP6n/1Y4ZfsoOVmlTx8BWvifBtPe+98h9eXctlQDuq92JeMMkY DbI2li/80awJgsZqxOXiGEzX7iwWw/XdulcScWv+2hRbbmOepZ5t0yO3hhP8RmgellrU Sxa6wQC1KNx0gy5fXL+1BHKfTR05M6JIY2wZyr81EipaGQgbf4hx7LUexJovIF1A2F5o RENQ== Received: by 10.68.234.7 with SMTP id ua7mr10702625pbc.91.1347356291853; Tue, 11 Sep 2012 02:38:11 -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 os1sm3321493pbc.31.2012.09.11.02.38.10 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 11 Sep 2012 02:38:11 -0700 (PDT) From: Anton Vorontsov To: Andrew Morton , Russell King , Jason Wessel , Greg Kroah-Hartman , Alan Cox Subject: [PATCH 05/12] tty/serial/amba-pl011: Implement poll_init callback Date: Tue, 11 Sep 2012 02:34:59 -0700 Message-Id: <1347356106-25368-5-git-send-email-anton.vorontsov@linaro.org> X-Mailer: git-send-email 1.7.11.5 In-Reply-To: <20120911093042.GA12471@lizard> References: <20120911093042.GA12471@lizard> X-Gm-Message-State: ALoCoQlc2Audu6u0qTSSHB2p/txUfsCbkaPik8n4cSNg31a4fT1GyQq13fjXCxooNuvT2xtgagsh 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, Brian Swetland , 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 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 --- 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