--- /dev/null
+/*
+ * drivers/char/watchdog/sp805-wdt.c
+ *
+ * Watchdog driver for ARM SP805 watchdog module
+ *
+ * Copyright (C) 2010 ST Microelectronics
+ * Viresh Kumar <viresh.linux@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2 or later. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/device.h>
+#include <linux/resource.h>
+#include <linux/amba/bus.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/pm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+/* default timeout in seconds */
+#define DEFAULT_TIMEOUT 60
+
+#define MODULE_NAME "sp805-wdt"
+
+/* watchdog register offsets and masks */
+#define WDTLOAD 0x000
+ #define LOAD_MIN 0x00000001
+ #define LOAD_MAX 0xFFFFFFFF
+#define WDTVALUE 0x004
+#define WDTCONTROL 0x008
+ /* control register masks */
+ #define INT_ENABLE (1 << 0)
+ #define RESET_ENABLE (1 << 1)
+#define WDTINTCLR 0x00C
+#define WDTRIS 0x010
+#define WDTMIS 0x014
+ #define INT_MASK (1 << 0)
+#define WDTLOCK 0xC00
+ #define UNLOCK 0x1ACCE551
+ #define LOCK 0x00000001
+
+/**
+ * struct sp805_wdt: sp805 wdt device structure
+ * @wdd: instance of struct watchdog_device
+ * @lock: spin lock protecting dev structure and io access
+ * @base: base address of wdt
+ * @clk: clock structure of wdt
+ * @adev: amba device structure of wdt
+ * @status: current status of wdt
+ * @load_val: load value to be set for current timeout
+ */
+struct sp805_wdt {
+ struct watchdog_device wdd;
+ spinlock_t lock;
+ void __iomem *base;
+ struct clk *clk;
+ struct amba_device *adev;
+ unsigned int load_val;
+};
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout,
+ "Set to 1 to keep watchdog running after device release");
+
+/* This routine finds load value that will reset system in required timout */
+static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
+{
+ struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
+ u64 load, rate;
+
+ rate = clk_get_rate(wdt->clk);
+
+ /*
+ * sp805 runs counter with given value twice, after the end of first
+ * counter it gives an interrupt and then starts counter again. If
+ * interrupt already occurred then it resets the system. This is why
+ * load is half of what should be required.
+ */
+ load = div_u64(rate, 2) * timeout - 1;
+
+ load = (load > LOAD_MAX) ? LOAD_MAX : load;
+ load = (load < LOAD_MIN) ? LOAD_MIN : load;
+
+ spin_lock(&wdt->lock);
+ wdt->load_val = load;
+ /* roundup timeout to closest positive integer value */
+ wdd->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
+ spin_unlock(&wdt->lock);
+
+ return 0;
+}
+
+/* returns number of seconds left for reset to occur */
+static unsigned int wdt_timeleft(struct watchdog_device *wdd)
+{
+ struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
+ u64 load, rate;
+
+ rate = clk_get_rate(wdt->clk);
+
+ spin_lock(&wdt->lock);
+ load = readl_relaxed(wdt->base + WDTVALUE);
+
+ /*If the interrupt is inactive then time left is WDTValue + WDTLoad. */
+ if (!(readl_relaxed(wdt->base + WDTRIS) & INT_MASK))
+ load += wdt->load_val + 1;
+ spin_unlock(&wdt->lock);
+
+ return div_u64(load, rate);
+}
+
+static int wdt_config(struct watchdog_device *wdd, bool ping)
+{
+ struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
+ int ret;
+
+ if (!ping) {
+
+ ret = clk_prepare_enable(wdt->clk);
+ if (ret) {
+ dev_err(&wdt->adev->dev, "clock enable fail");
+ return ret;
+ }
+ }
+
+ spin_lock(&wdt->lock);
+
+ writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
+ writel_relaxed(wdt->load_val, wdt->base + WDTLOAD);
+
+ if (!ping) {
+ writel_relaxed(INT_MASK, wdt->base + WDTINTCLR);
+ writel_relaxed(INT_ENABLE | RESET_ENABLE, wdt->base +
+ WDTCONTROL);
+ }
+
+ writel_relaxed(LOCK, wdt->base + WDTLOCK);
+
+ /* Flush posted writes. */
+ readl_relaxed(wdt->base + WDTLOCK);
+ spin_unlock(&wdt->lock);
+
+ return 0;
+}
+
+static int wdt_ping(struct watchdog_device *wdd)
+{
+ return wdt_config(wdd, true);
+}
+
+/* enables watchdog timers reset */
+static int wdt_enable(struct watchdog_device *wdd)
+{
+ return wdt_config(wdd, false);
+}
+
+/* disables watchdog timers reset */
+static int wdt_disable(struct watchdog_device *wdd)
+{
+ struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
+
+ spin_lock(&wdt->lock);
+
+ writel_relaxed(UNLOCK, wdt->base + WDTLOCK);
+ writel_relaxed(0, wdt->base + WDTCONTROL);
+ writel_relaxed(LOCK, wdt->base + WDTLOCK);
+
+ /* Flush posted writes. */
+ readl_relaxed(wdt->base + WDTLOCK);
+ spin_unlock(&wdt->lock);
+
+ clk_disable_unprepare(wdt->clk);
+
+ return 0;
+}
+
+static const struct watchdog_info wdt_info = {
+ .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+ .identity = MODULE_NAME,
+};
+
+static const struct watchdog_ops wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = wdt_enable,
+ .stop = wdt_disable,
+ .ping = wdt_ping,
+ .set_timeout = wdt_setload,
+ .get_timeleft = wdt_timeleft,
+};
+
+static int
+sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
+{
+ struct sp805_wdt *wdt;
+ int ret = 0;
+
+ wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ wdt->base = devm_ioremap_resource(&adev->dev, &adev->res);
+ if (IS_ERR(wdt->base))
+ return PTR_ERR(wdt->base);
+
+ wdt->clk = devm_clk_get(&adev->dev, NULL);
+ if (IS_ERR(wdt->clk)) {
+ dev_warn(&adev->dev, "Clock not found\n");
+ ret = PTR_ERR(wdt->clk);
+ goto err;
+ }
+
+ wdt->adev = adev;
+ wdt->wdd.info = &wdt_info;
+ wdt->wdd.ops = &wdt_ops;
+
+ spin_lock_init(&wdt->lock);
+ watchdog_set_nowayout(&wdt->wdd, nowayout);
+ watchdog_set_drvdata(&wdt->wdd, wdt);
+ wdt_setload(&wdt->wdd, DEFAULT_TIMEOUT);
+
+ ret = watchdog_register_device(&wdt->wdd);
+ if (ret) {
+ dev_err(&adev->dev, "watchdog_register_device() failed: %d\n",
+ ret);
+ goto err;
+ }
+ amba_set_drvdata(adev, wdt);
+
+ dev_info(&adev->dev, "registration successful\n");
+ return 0;
+
+err:
+ dev_err(&adev->dev, "Probe Failed!!!\n");
+ return ret;
+}
+
+static int sp805_wdt_remove(struct amba_device *adev)
+{
+ struct sp805_wdt *wdt = amba_get_drvdata(adev);
+
+ watchdog_unregister_device(&wdt->wdd);
+ watchdog_set_drvdata(&wdt->wdd, NULL);
+
+ return 0;
+}
+
+static int __maybe_unused sp805_wdt_suspend(struct device *dev)
+{
+ struct sp805_wdt *wdt = dev_get_drvdata(dev);
+
+ if (watchdog_active(&wdt->wdd))
+ return wdt_disable(&wdt->wdd);
+
+ return 0;
+}
+
+static int __maybe_unused sp805_wdt_resume(struct device *dev)
+{
+ struct sp805_wdt *wdt = dev_get_drvdata(dev);
+
+ if (watchdog_active(&wdt->wdd))
+ return wdt_enable(&wdt->wdd);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(sp805_wdt_dev_pm_ops, sp805_wdt_suspend,
+ sp805_wdt_resume);
+
+static struct amba_id sp805_wdt_ids[] = {
+ {
+ .id = 0x00141805,
+ .mask = 0x00ffffff,
+ },
+ { 0, 0 },
+};
+
+MODULE_DEVICE_TABLE(amba, sp805_wdt_ids);
+
+static struct amba_driver sp805_wdt_driver = {
+ .drv = {
+ .name = MODULE_NAME,
+ .pm = &sp805_wdt_dev_pm_ops,
+ },
+ .id_table = sp805_wdt_ids,
+ .probe = sp805_wdt_probe,
+ .remove = sp805_wdt_remove,
+};
+
+module_amba_driver(sp805_wdt_driver);
+
+MODULE_AUTHOR("Viresh Kumar <viresh.linux@gmail.com>");
+MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff