From patchwork Wed Sep 19 23:41:56 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Vorontsov X-Patchwork-Id: 1481741 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 820DDDF280 for ; Wed, 19 Sep 2012 23:49:11 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TETzB-0006eP-Os; Wed, 19 Sep 2012 23:47:18 +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 1TETz6-00069i-20 for linux-arm-kernel@lists.infradead.org; Wed, 19 Sep 2012 23:47:13 +0000 Received: by mail-pb0-f49.google.com with SMTP id rq8so3820836pbb.36 for ; Wed, 19 Sep 2012 16:47:11 -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=yYu6YrOWSIknwmcDYgxnk8PzjIw2OFNriDUs+BRABV8=; b=LsVsq7VRcMwCdtyln+bC5a70FidSojAFnoHyHm6liC57ScTYsgzuC3nPZOcXpC56nl SiIJrtZpclV50EBmQh5CQLphi8bIYMc7iMPAmbPJjSduZm1hydQENaP6X5z8RbtMS7qX OhD4CS6cRpdS4mYdyOfne64uocDCstXcgrWBWyp+BcIMivHXRu8TxRtClSF6bPkwNO7P vxqprjxuJSUKQQLDiA5H48KolhrtEtKfF9UCdlRdTkoY+si4+gqWb/tDbWX/X6PwuDLT d8BmxCUI4v/kbfLK6xfqA5RReWjmOaVtje/9hyywvC8hPVWJiLSqWn8HrjOFXSBiV103 G1BA== Received: by 10.66.77.7 with SMTP id o7mr980077paw.37.1348098431712; Wed, 19 Sep 2012 16:47:11 -0700 (PDT) Received: from localhost (ip-64-134-220-225.public.wayport.net. [64.134.220.225]) by mx.google.com with ESMTPS id l2sm1442665pay.25.2012.09.19.16.46.53 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 19 Sep 2012 16:47:11 -0700 (PDT) From: Anton Vorontsov To: Andrew Morton , Russell King , Jason Wessel , Greg Kroah-Hartman , Alan Cox Subject: [PATCH 05/11] tty/serial/amba-pl011: Implement poll_init callback Date: Wed, 19 Sep 2012 16:41:56 -0700 Message-Id: <1348098122-11041-5-git-send-email-anton.vorontsov@linaro.org> X-Mailer: git-send-email 1.7.11.5 In-Reply-To: <20120919234003.GA24143@lizard> References: <20120919234003.GA24143@lizard> X-Gm-Message-State: ALoCoQnwEMijZP+zYJ7m+37x0O2wZqge0ytXs0+C2BeW3adimuYN98fiP+SIurzG8QX9WcLcQTng 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, Thomas Gleixner , 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 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