From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934221AbcBDQZ4 (ORCPT ); Thu, 4 Feb 2016 11:25:56 -0500 Received: from mail-oi0-f47.google.com ([209.85.218.47]:32772 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755217AbcBDQZw (ORCPT ); Thu, 4 Feb 2016 11:25:52 -0500 MIME-Version: 1.0 In-Reply-To: <1454519923-25230-5-git-send-email-fu.wei@linaro.org> References: <1454519923-25230-1-git-send-email-fu.wei@linaro.org> <1454519923-25230-5-git-send-email-fu.wei@linaro.org> Date: Thu, 4 Feb 2016 09:25:51 -0700 Message-ID: Subject: Re: [PATCH v10 4/5] Watchdog: introduce ARM SBSA watchdog driver From: Mathieu Poirier To: fu.wei@linaro.org Cc: Rob Herring , =?UTF-8?Q?Pawe=C5=82_Moll?= , Mark Rutland , Ian Campbell , Kumar Gala , wim@iguana.be, linux@roeck-us.net, Jon Corbet , Catalin Marinas , Will Deacon , Suravee.Suthikulpanit@amd.com, "linux-kernel@vger.kernel.org" , linux-watchdog@vger.kernel.org, linux-doc@vger.kernel.org, "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , linaro-acpi@lists.linaro.org, rruigrok@codeaurora.org, harba@codeaurora.org, Christopher Covington , timur@codeaurora.org, dyoung@redhat.com, panand@redhat.com, graeme.gregory@linaro.org, al.stone@linaro.org, hanjun.guo@linaro.org, jcm@redhat.com, Arnd Bergmann , leo.duran@amd.com, Sudeep Holla Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3 February 2016 at 10:18, wrote: > From: Fu Wei > > According to Server Base System Architecture (SBSA) specification, > the SBSA Generic Watchdog has two stage timeouts: the first signal (WS0) > is for alerting the system by interrupt, the second one (WS1) is a real > hardware reset. > > This patch initially implements a simple single stage watchdog driver: > when the timeout is reached, your system will be reset by the second > signal (WS1). > The first signal (WS0) is ignored in this driver. > > This driver bases on linux kernel watchdog framework, so it can get > timeout from module parameter and FDT at the driver init stage. > > Signed-off-by: Fu Wei > Reviewed-by: Graeme Gregory > Tested-by: Pratyush Anand > --- > drivers/watchdog/Kconfig | 17 +++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/sbsa_gwdt.c | 322 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 340 insertions(+) > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 4f0e7be..4ab1b05 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -201,6 +201,23 @@ config ARM_SP805_WATCHDOG > ARM Primecell SP805 Watchdog timer. This will reboot your system when > the timeout is reached. > > +config ARM_SBSA_WATCHDOG > + tristate "ARM SBSA Generic Watchdog" > + depends on ARM64 > + depends on ARM_ARCH_TIMER > + select WATCHDOG_CORE > + help > + ARM SBSA Generic Watchdog has two stage timeouts: > + the first signal (WS0) is for alerting the system by interrupt, > + the second one (WS1) is a real hardware reset. > + More details: ARM DEN0029B - Server Base System Architecture (SBSA) > + > + This is a simple single stage driver: when the timeout is reached, > + your system will be reset by WS1. The first signal (WS0) is ignored. > + > + To compile this driver as module, choose M here: The module > + will be called sbsa_gwdt. > + > config ASM9260_WATCHDOG > tristate "Alphascale ASM9260 watchdog" > depends on MACH_ASM9260 > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index f566753..f9826d4 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -30,6 +30,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o > > # ARM Architecture > obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o > +obj-$(CONFIG_ARM_SBSA_WATCHDOG) += sbsa_gwdt.o > obj-$(CONFIG_ASM9260_WATCHDOG) += asm9260_wdt.o > obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o > obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o > diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c > new file mode 100644 > index 0000000..5a2dba3 > --- /dev/null > +++ b/drivers/watchdog/sbsa_gwdt.c > @@ -0,0 +1,322 @@ > +/* > + * SBSA(Server Base System Architecture) Generic Watchdog driver > + * > + * Copyright (c) 2015, Linaro Ltd. > + * Author: Fu Wei > + * Suravee Suthikulpanit > + * Al Stone > + * Timur Tabi > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License 2 as published > + * by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * This SBSA Generic watchdog driver is a single stage timeout version. > + * Since this watchdog timer has two stages, and each stage is determined > + * by WOR. So the timeout is (WOR * 2). > + * When first timeout is reached, WS0 is triggered, the interrupt > + * triggered by WS0 will be ignored, then the second watch period starts; > + * when second timeout is reached, then WS1 is triggered, system reset. > + * > + * More details about the hardware specification of this device: > + * ARM DEN0029B - Server Base System Architecture (SBSA) > + * > + * SBSA GWDT: |--------WOR-------WS0--------WOR-------WS1 > + * |----------------timeout----------------reset > + * > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +/* SBSA Generic Watchdog register definitions */ > +/* refresh frame */ > +#define SBSA_GWDT_WRR 0x000 > + > +/* control frame */ > +#define SBSA_GWDT_WCS 0x000 > +#define SBSA_GWDT_WOR 0x008 > +#define SBSA_GWDT_WCV 0x010 > + > +/* refresh/control frame */ > +#define SBSA_GWDT_W_IIDR 0xfcc > +#define SBSA_GWDT_IDR 0xfd0 > + > +/* Watchdog Control and Status Register */ > +#define SBSA_GWDT_WCS_EN BIT(0) > +#define SBSA_GWDT_WCS_WS0 BIT(1) > +#define SBSA_GWDT_WCS_WS1 BIT(2) > + > +/** > + * struct sbsa_gwdt - Internal representation of the SBSA GWDT > + * @wdd: kernel watchdog_device structure > + * @clk: store the System Counter clock frequency, in Hz. > + * @refresh_base: Virtual address of the watchdog refresh frame > + * @control_base: Virtual address of the watchdog control frame > + */ > +struct sbsa_gwdt { > + struct watchdog_device wdd; > + u32 clk; > + void __iomem *refresh_base; > + void __iomem *control_base; > +}; > + > +#define to_sbsa_gwdt(e) container_of(e, struct sbsa_gwdt, wdd) > + > +#define DEFAULT_TIMEOUT 20 /* seconds, the 1st + 2nd watch periods*/ > + > +static unsigned int timeout; > +module_param(timeout, uint, 0); > +MODULE_PARM_DESC(timeout, > + "Watchdog timeout in seconds. (>=0, default=" > + __MODULE_STRING(DEFAULT_TIMEOUT) ")"); > + > +static bool nowayout = WATCHDOG_NOWAYOUT; > +module_param(nowayout, bool, S_IRUGO); > +MODULE_PARM_DESC(nowayout, > + "Watchdog cannot be stopped once started (default=" > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > + > +/* > + * watchdog operation functions > + */ > +static int sbsa_gwdt_set_timeout(struct watchdog_device *wdd, > + unsigned int timeout) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + wdd->timeout = timeout; > + writel(timeout / 2 * gwdt->clk, gwdt->control_base + SBSA_GWDT_WOR); > + > + return 0; > +} > + > +static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + u64 timeleft = readq(gwdt->control_base + SBSA_GWDT_WCV) - > + arch_counter_get_cntvct(); > + > + do_div(timeleft, gwdt->clk); > + > + if (readl(gwdt->control_base + SBSA_GWDT_WCS) & SBSA_GWDT_WCS_WS0) > + return timeleft; > + > + return timeleft + wdd->timeout / 2; It would be great to have a comment whenever hard coded values are used. That way people understand why things were set this way. The same applies for the rest of this patch. > +} > + > +static int sbsa_gwdt_keepalive(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + /* > + * Writing WRR for an explicit watchdog refresh. > + * You can write anyting(like 0xc0ffee). > + */ > + writel(0xc0ffee, gwdt->refresh_base + SBSA_GWDT_WRR); > + > + return 0; > +} > + > +static unsigned int sbsa_gwdt_status(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + u32 status = readl(gwdt->control_base + SBSA_GWDT_WCS); > + > + /* is the watchdog timer running? */ > + return (status & SBSA_GWDT_WCS_EN) << WDOG_ACTIVE; > +} > + > +static int sbsa_gwdt_start(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + /* writing WCS will cause an explicit watchdog refresh */ > + writel(SBSA_GWDT_WCS_EN, gwdt->control_base + SBSA_GWDT_WCS); > + > + return sbsa_gwdt_keepalive(wdd); > +} > + > +static int sbsa_gwdt_stop(struct watchdog_device *wdd) > +{ > + struct sbsa_gwdt *gwdt = to_sbsa_gwdt(wdd); > + > + writel(0, gwdt->control_base + SBSA_GWDT_WCS); > + > + return 0; > +} > + > +static struct watchdog_info sbsa_gwdt_info = { > + .identity = "SBSA Generic Watchdog", > + .options = WDIOF_SETTIMEOUT | > + WDIOF_KEEPALIVEPING | > + WDIOF_MAGICCLOSE | > + WDIOF_CARDRESET, > +}; > + > +static struct watchdog_ops sbsa_gwdt_ops = { > + .owner = THIS_MODULE, > + .start = sbsa_gwdt_start, > + .stop = sbsa_gwdt_stop, > + .status = sbsa_gwdt_status, > + .ping = sbsa_gwdt_keepalive, > + .set_timeout = sbsa_gwdt_set_timeout, > + .get_timeleft = sbsa_gwdt_get_timeleft, > +}; > + > +static int sbsa_gwdt_probe(struct platform_device *pdev) > +{ > + void __iomem *rf_base, *cf_base; > + struct device *dev = &pdev->dev; > + struct watchdog_device *wdd; > + struct sbsa_gwdt *gwdt; > + struct resource *res; > + u32 status; > + int ret; > + > + gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL); > + if (!gwdt) > + return -ENOMEM; > + platform_set_drvdata(pdev, gwdt); > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + cf_base = devm_ioremap_resource(dev, res); > + if (IS_ERR(cf_base)) > + return PTR_ERR(cf_base); > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 1); > + rf_base = devm_ioremap_resource(dev, res); > + if (IS_ERR(rf_base)) > + return PTR_ERR(rf_base); > + > + /* > + * Get the frequency of system counter from the cp15 interface of ARM > + * Generic timer. We don't need to check it, because if it returns "0", > + * system would panic in very early stage. > + */ > + gwdt->clk = arch_timer_get_cntfrq(); > + gwdt->refresh_base = rf_base; > + gwdt->control_base = cf_base; > + > + wdd = &gwdt->wdd; > + wdd->parent = dev; > + wdd->info = &sbsa_gwdt_info; > + wdd->ops = &sbsa_gwdt_ops; > + watchdog_set_drvdata(wdd, gwdt); > + watchdog_set_nowayout(wdd, nowayout); > + > + wdd->min_timeout = 2; > + wdd->max_timeout = U32_MAX / gwdt->clk * 2; > + wdd->timeout = DEFAULT_TIMEOUT; > + watchdog_init_timeout(wdd, timeout, dev); > + > + status = readl(gwdt->control_base + SBSA_GWDT_WCS); > + if (status & SBSA_GWDT_WCS_WS1) { > + dev_warn(dev, "System reset by WDT.\n"); > + wdd->bootstatus |= WDIOF_CARDRESET; > + } > + > + ret = watchdog_register_device(wdd); > + if (ret) > + return ret; > + > + /* > + * Update timeout to WOR. > + * Because of the explicit watchdog refresh mechanism, > + * it's also a ping, if watchdog is enabled. > + */ > + sbsa_gwdt_set_timeout(wdd, wdd->timeout); > + > + dev_info(dev, "Initialized with %ds timeout @ %u Hz%s\n", wdd->timeout, > + gwdt->clk, status & SBSA_GWDT_WCS_EN ? " [enabled]" : ""); > + > + return 0; > +} > + > +static void sbsa_gwdt_shutdown(struct platform_device *pdev) > +{ > + struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev); > + > + sbsa_gwdt_stop(&gwdt->wdd); > +} > + > +static int sbsa_gwdt_remove(struct platform_device *pdev) > +{ > + struct sbsa_gwdt *gwdt = platform_get_drvdata(pdev); > + > + watchdog_unregister_device(&gwdt->wdd); > + > + return 0; > +} > + > +/* Disable watchdog if it is active during suspend */ > +static int __maybe_unused sbsa_gwdt_suspend(struct device *dev) > +{ > + struct sbsa_gwdt *gwdt = dev_get_drvdata(dev); > + > + if (watchdog_active(&gwdt->wdd)) > + sbsa_gwdt_stop(&gwdt->wdd); > + > + return 0; > +} > + > +/* Enable watchdog and configure it if necessary */ > +static int __maybe_unused sbsa_gwdt_resume(struct device *dev) > +{ > + struct sbsa_gwdt *gwdt = dev_get_drvdata(dev); > + > + if (watchdog_active(&gwdt->wdd)) > + sbsa_gwdt_start(&gwdt->wdd); > + > + return 0; > +} > + > +static const struct dev_pm_ops sbsa_gwdt_pm_ops = { > + SET_SYSTEM_SLEEP_PM_OPS(sbsa_gwdt_suspend, sbsa_gwdt_resume) > +}; > + > +static const struct of_device_id sbsa_gwdt_of_match[] = { > + { .compatible = "arm,sbsa-gwdt", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, sbsa_gwdt_of_match); > + > +static const struct platform_device_id sbsa_gwdt_pdev_match[] = { > + { .name = "sbsa-gwdt", }, > + {}, > +}; > +MODULE_DEVICE_TABLE(platform, sbsa_gwdt_pdev_match); > + > +static struct platform_driver sbsa_gwdt_driver = { > + .driver = { > + .name = "sbsa-gwdt", > + .pm = &sbsa_gwdt_pm_ops, > + .of_match_table = sbsa_gwdt_of_match, > + }, > + .probe = sbsa_gwdt_probe, > + .remove = sbsa_gwdt_remove, > + .shutdown = sbsa_gwdt_shutdown, > + .id_table = sbsa_gwdt_pdev_match, > +}; > + > +module_platform_driver(sbsa_gwdt_driver); > + > +MODULE_DESCRIPTION("SBSA Generic Watchdog Driver"); > +MODULE_AUTHOR("Fu Wei "); > +MODULE_AUTHOR("Suravee Suthikulpanit "); > +MODULE_AUTHOR("Al Stone "); > +MODULE_AUTHOR("Timur Tabi "); > +MODULE_LICENSE("GPL v2"); > -- > 2.5.0 >