From patchwork Mon Aug 20 14:47:23 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anton Vorontsov X-Patchwork-Id: 10808 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id A603323E56 for ; Mon, 20 Aug 2012 14:50:11 +0000 (UTC) Received: from mail-gh0-f180.google.com (mail-gh0-f180.google.com [209.85.160.180]) by fiordland.canonical.com (Postfix) with ESMTP id 719ACA18B62 for ; Mon, 20 Aug 2012 14:50:05 +0000 (UTC) Received: by ghbg10 with SMTP id g10so5355417ghb.11 for ; Mon, 20 Aug 2012 07:50:10 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-forwarded-to:x-forwarded-for:delivered-to:received-spf:from:to:cc :subject:date:message-id:x-mailer:in-reply-to:references :x-gm-message-state; bh=sVkM18KJVke0myVq1r52F5+We4/BP9hfRDlsp/s7BI8=; b=Sx8O6tmg/QMHQiLA3+tb/Ys2aJDOZUHtL8YH1H1xqvKaziplAF1rITPu99LqUq6Sl3 21VmktGjLq7V1MNCjip6694641hzAyb3sPF8poFe20MYeibYwsu838pSjZpH8qYrH3hR 1ugj8JHLHjAW8rpUL9dleVW7vXI7cVHDjGSYbG94dj85LaAFFJp+MQlEUqkygOuQJF/u Bqj0zJo7Gl4eOHOk8wWxn8sxBoq/XQfW1dR+nYfto2pZo03o7JI3L4P20uU9STnEqcT3 jT4Ym+7LIr2EnyatOvLUjmUxPWR2eb1gH1CT3wGSBinUpJZ4XByWGy3rXd/+xBvw8T8I Ptuw== Received: by 10.50.182.161 with SMTP id ef1mr10197193igc.0.1345474210234; Mon, 20 Aug 2012 07:50:10 -0700 (PDT) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.50.184.232 with SMTP id ex8csp87703igc; Mon, 20 Aug 2012 07:50:09 -0700 (PDT) Received: by 10.68.224.133 with SMTP id rc5mr34783136pbc.130.1345474209410; Mon, 20 Aug 2012 07:50:09 -0700 (PDT) Received: from mail-pz0-f50.google.com (mail-pz0-f50.google.com [209.85.210.50]) by mx.google.com with ESMTPS id qt3si26954278pbc.353.2012.08.20.07.50.09 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 20 Aug 2012 07:50:09 -0700 (PDT) Received-SPF: neutral (google.com: 209.85.210.50 is neither permitted nor denied by best guess record for domain of anton.vorontsov@linaro.org) client-ip=209.85.210.50; Authentication-Results: mx.google.com; spf=neutral (google.com: 209.85.210.50 is neither permitted nor denied by best guess record for domain of anton.vorontsov@linaro.org) smtp.mail=anton.vorontsov@linaro.org Received: by mail-pz0-f50.google.com with SMTP id e7so2499989dad.37 for ; Mon, 20 Aug 2012 07:50:09 -0700 (PDT) Received: by 10.68.240.138 with SMTP id wa10mr34818185pbc.145.1345474209097; Mon, 20 Aug 2012 07:50:09 -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 gt2sm11221511pbc.62.2012.08.20.07.50.08 (version=TLSv1/SSLv3 cipher=OTHER); Mon, 20 Aug 2012 07:50:08 -0700 (PDT) From: Anton Vorontsov To: Russell King , Jason Wessel , Greg Kroah-Hartman , Alan Cox Cc: =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= , Colin Cross , John Stultz , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com, kgdb-bugreport@lists.sourceforge.net Subject: [PATCH 05/12] tty/serial/amba-pl011: Implement poll_init callback Date: Mon, 20 Aug 2012 07:47:23 -0700 Message-Id: <1345474050-8339-5-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: ALoCoQlr86pBRUkmKj+JGzsA+xeRHZP6A6Xb/5O79o615fGQOYMVWT+BtBMLMR6QjvJaozIR1wTk 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 | 47 ++++++++++++++++++++++++++++++----------- 1 file changed, 35 insertions(+), 12 deletions(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index d3553b5..90f2302 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1310,10 +1310,9 @@ static void pl010_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 */ @@ -1342,6 +1341,39 @@ 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; +clk_unprep: + clk_unprepare(uap->clk); +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); @@ -1400,21 +1432,11 @@ 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(uap->clk); - clk_unprep: clk_unprepare(uap->clk); - out: return retval; } @@ -1696,6 +1718,7 @@ static struct uart_ops amba_pl011_pops = { .config_port = pl010_config_port, .verify_port = pl010_verify_port, #ifdef CONFIG_CONSOLE_POLL + .poll_init = pl011_hwinit, .poll_get_char = pl010_get_poll_char, .poll_put_char = pl010_put_poll_char, #endif