diff options
Diffstat (limited to 'drivers/watchdog/sbsa_gwdt.c')
| -rw-r--r-- | drivers/watchdog/sbsa_gwdt.c | 408 |
1 files changed, 408 insertions, 0 deletions
diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c new file mode 100644 index 000000000000..ad383f6f15fc --- /dev/null +++ b/drivers/watchdog/sbsa_gwdt.c @@ -0,0 +1,408 @@ +/* + * SBSA(Server Base System Architecture) Generic Watchdog driver + * + * Copyright (c) 2015, Linaro Ltd. + * Author: Fu Wei <fu.wei@linaro.org> + * Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> + * Al Stone <al.stone@linaro.org> + * Timur Tabi <timur@codeaurora.org> + * + * 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. + * + * 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 about the hardware specification of this device: + * ARM DEN0029B - Server Base System Architecture (SBSA) + * + * This driver can operate ARM SBSA Generic Watchdog as a single stage watchdog + * or a two stages watchdog, it's set up by the module parameter "action". + * In the single stage mode, when the timeout is reached, your system + * will be reset by WS1. The first signal (WS0) is ignored. + * In the two stages mode, when the timeout is reached, the first signal (WS0) + * will trigger panic. If the system is getting into trouble and cannot be reset + * by panic or restart properly by the kdump kernel(if supported), then the + * second stage (as long as the first stage) will be reached, system will be + * reset by WS1. This function can help administrator to backup the system + * context info by panic console output or kdump. + * + * SBSA GWDT: + * if action is 1 (the two stages mode): + * |--------WOR-------WS0--------WOR-------WS1 + * |----timeout-----(panic)----timeout-----reset + * + * if action is 0 (the single stage mode): + * |------WOR-----WS0(ignored)-----WOR------WS1 + * |--------------timeout-------------------reset + * + * Note: Since this watchdog timer has two stages, and each stage is determined + * by WOR, in the single stage mode, the timeout is (WOR * 2); in the two + * stages mode, the timeout is WOR. The maximum timeout in the two stages mode + * is half of that in the single stage mode. + * + */ + +#include <linux/io.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/uaccess.h> +#include <linux/watchdog.h> +#include <asm/arch_timer.h> + +#define DRV_NAME "sbsa-gwdt" +#define WATCHDOG_NAME "SBSA Generic Watchdog" + +/* 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 DEFAULT_TIMEOUT 10 /* seconds */ + +static unsigned int timeout; +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, + "Watchdog timeout in seconds. (>=0, default=" + __MODULE_STRING(DEFAULT_TIMEOUT) ")"); + +/* + * action refers to action taken when watchdog gets WS0 + * 0 = skip + * 1 = panic + * defaults to skip (0) + */ +static int action; +module_param(action, int, 0); +MODULE_PARM_DESC(action, "after watchdog gets WS0 interrupt, do: " + "0 = skip(*) 1 = panic"); + +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 = watchdog_get_drvdata(wdd); + + wdd->timeout = timeout; + + if (action) + writel(gwdt->clk * timeout, + gwdt->control_base + SBSA_GWDT_WOR); + else + /* + * In the single stage mode, The first signal (WS0) is ignored, + * the timeout is (WOR * 2), so the WOR should be configured + * to half value of timeout. + */ + writel(gwdt->clk / 2 * timeout, + gwdt->control_base + SBSA_GWDT_WOR); + + return 0; +} + +static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd) +{ + struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd); + u64 timeleft = 0; + + /* + * In the single stage mode, if WS0 is deasserted + * (watchdog is in the first stage), + * timeleft = WOR + (WCV - system counter) + */ + if (!action && + !(readl(gwdt->control_base + SBSA_GWDT_WCS) & SBSA_GWDT_WCS_WS0)) + timeleft += readl(gwdt->control_base + SBSA_GWDT_WOR); + + timeleft += readq(gwdt->control_base + SBSA_GWDT_WCV) - + arch_counter_get_cntvct(); + + do_div(timeleft, gwdt->clk); + + return timeleft; +} + +static int sbsa_gwdt_keepalive(struct watchdog_device *wdd) +{ + struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd); + + /* + * Writing WRR for an explicit watchdog refresh. + * You can write anyting (like 0). + */ + writel(0, gwdt->refresh_base + SBSA_GWDT_WRR); + + return 0; +} + +static unsigned int sbsa_gwdt_status(struct watchdog_device *wdd) +{ + struct sbsa_gwdt *gwdt = watchdog_get_drvdata(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 = watchdog_get_drvdata(wdd); + + /* writing WCS will cause an explicit watchdog refresh */ + writel(SBSA_GWDT_WCS_EN, gwdt->control_base + SBSA_GWDT_WCS); + + return 0; +} + +static int sbsa_gwdt_stop(struct watchdog_device *wdd) +{ + struct sbsa_gwdt *gwdt = watchdog_get_drvdata(wdd); + + /* Simply write 0 to WCS to clean WCS_EN bit */ + writel(0, gwdt->control_base + SBSA_GWDT_WCS); + + return 0; +} + +static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id) +{ + panic(WATCHDOG_NAME " timeout"); + + return IRQ_HANDLED; +} + +static struct watchdog_info sbsa_gwdt_info = { + .identity = WATCHDOG_NAME, + .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; + int ret, irq; + u32 status; + + 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; + wdd->min_timeout = 1; + wdd->max_timeout = U32_MAX / gwdt->clk; + wdd->timeout = DEFAULT_TIMEOUT; + watchdog_set_drvdata(wdd, gwdt); + watchdog_set_nowayout(wdd, nowayout); + + status = readl(cf_base + SBSA_GWDT_WCS); + if (status & SBSA_GWDT_WCS_WS1) { + dev_warn(dev, "System reset by WDT.\n"); + wdd->bootstatus |= WDIOF_CARDRESET; + } + + if (action) { + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + action = 0; + dev_warn(dev, "unable to get ws0 interrupt.\n"); + } else { + /* + * In case there is a pending ws0 interrupt, just ping + * the watchdog before registering the interrupt routine + */ + writel(0, rf_base + SBSA_GWDT_WRR); + if (devm_request_irq(dev, irq, sbsa_gwdt_interrupt, 0, + pdev->name, gwdt)) { + action = 0; + dev_warn(dev, "unable to request IRQ %d.\n", + irq); + } + } + if (!action) + dev_warn(dev, "falling back to single stage mode.\n"); + } + /* + * In the single stage mode, The first signal (WS0) is ignored, + * the timeout is (WOR * 2), so the maximum timeout should be doubled. + */ + if (!action) + wdd->max_timeout *= 2; + + watchdog_init_timeout(wdd, timeout, dev); + /* + * 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); + + ret = watchdog_register_device(wdd); + if (ret) + return ret; + + dev_info(dev, "Initialized with %ds timeout @ %u Hz, action=%d.%s\n", + wdd->timeout, gwdt->clk, action, + 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 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 = DRV_NAME, }, + {}, +}; +MODULE_DEVICE_TABLE(platform, sbsa_gwdt_pdev_match); + +static struct platform_driver sbsa_gwdt_driver = { + .driver = { + .name = DRV_NAME, + .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 <fu.wei@linaro.org>"); +MODULE_AUTHOR("Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>"); +MODULE_AUTHOR("Al Stone <al.stone@linaro.org>"); +MODULE_AUTHOR("Timur Tabi <timur@codeaurora.org>"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:" DRV_NAME); |