1 files changed, 224 insertions, 0 deletions

diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
new file mode 100644
index 000000000000..aa85618c4d03
--- /dev/null
+++ b/drivers/watchdog/qcom-wdt.c
@@ -0,0 +1,224 @@
+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 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.
+ *
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/watchdog.h>
+
+#define WDT_RST         0x0
+#define WDT_EN          0x8
+#define WDT_BITE_TIME   0x24
+
+struct qcom_wdt {
+        struct watchdog_device  wdd;
+        struct clk              *clk;
+        unsigned long           rate;
+        struct notifier_block   restart_nb;
+        void __iomem            *base;
+};
+
+static inline
+struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
+{
+        return container_of(wdd, struct qcom_wdt, wdd);
+}
+
+static int qcom_wdt_start(struct watchdog_device *wdd)
+{
+        struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+        writel(0, wdt->base + WDT_EN);
+        writel(1, wdt->base + WDT_RST);
+        writel(wdd->timeout * wdt->rate, wdt->base + WDT_BITE_TIME);
+        writel(1, wdt->base + WDT_EN);
+        return 0;
+}
+
+static int qcom_wdt_stop(struct watchdog_device *wdd)
+{
+        struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+        writel(0, wdt->base + WDT_EN);
+        return 0;
+}
+
+static int qcom_wdt_ping(struct watchdog_device *wdd)
+{
+        struct qcom_wdt *wdt = to_qcom_wdt(wdd);
+
+        writel(1, wdt->base + WDT_RST);
+        return 0;
+}
+
+static int qcom_wdt_set_timeout(struct watchdog_device *wdd,
+                                unsigned int timeout)
+{
+        wdd->timeout = timeout;
+        return qcom_wdt_start(wdd);
+}
+
+static const struct watchdog_ops qcom_wdt_ops = {
+        .start          = qcom_wdt_start,
+        .stop           = qcom_wdt_stop,
+        .ping           = qcom_wdt_ping,
+        .set_timeout    = qcom_wdt_set_timeout,
+        .owner          = THIS_MODULE,
+};
+
+static const struct watchdog_info qcom_wdt_info = {
+        .options        = WDIOF_KEEPALIVEPING
+                        | WDIOF_MAGICCLOSE
+                        | WDIOF_SETTIMEOUT,
+        .identity       = KBUILD_MODNAME,
+};
+
+static int qcom_wdt_restart(struct notifier_block *nb, unsigned long action,
+                            void *data)
+{
+        struct qcom_wdt *wdt = container_of(nb, struct qcom_wdt, restart_nb);
+        u32 timeout;
+
+        /*
+         * Trigger watchdog bite:
+         *    Setup BITE_TIME to be 128ms, and enable WDT.
+         */
+        timeout = 128 * wdt->rate / 1000;
+
+        writel(0, wdt->base + WDT_EN);
+        writel(1, wdt->base + WDT_RST);
+        writel(timeout, wdt->base + WDT_BITE_TIME);
+        writel(1, wdt->base + WDT_EN);
+
+        /*
+         * Actually make sure the above sequence hits hardware before sleeping.
+         */
+        wmb();
+
+        msleep(150);
+        return NOTIFY_DONE;
+}
+
+static int qcom_wdt_probe(struct platform_device *pdev)
+{
+        struct qcom_wdt *wdt;
+        struct resource *res;
+        int ret;
+
+        wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+        if (!wdt)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        wdt->base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(wdt->base))
+                return PTR_ERR(wdt->base);
+
+        wdt->clk = devm_clk_get(&pdev->dev, NULL);
+        if (IS_ERR(wdt->clk)) {
+                dev_err(&pdev->dev, "failed to get input clock\n");
+                return PTR_ERR(wdt->clk);
+        }
+
+        ret = clk_prepare_enable(wdt->clk);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to setup clock\n");
+                return ret;
+        }
+
+        /*
+         * We use the clock rate to calculate the max timeout, so ensure it's
+         * not zero to avoid a divide-by-zero exception.
+         *
+         * WATCHDOG_CORE assumes units of seconds, if the WDT is clocked such
+         * that it would bite before a second elapses it's usefulness is
+         * limited.  Bail if this is the case.
+         */
+        wdt->rate = clk_get_rate(wdt->clk);
+        if (wdt->rate == 0 ||
+            wdt->rate > 0x10000000U) {
+                dev_err(&pdev->dev, "invalid clock rate\n");
+                ret = -EINVAL;
+                goto err_clk_unprepare;
+        }
+
+        wdt->wdd.dev = &pdev->dev;
+        wdt->wdd.info = &qcom_wdt_info;
+        wdt->wdd.ops = &qcom_wdt_ops;
+        wdt->wdd.min_timeout = 1;
+        wdt->wdd.max_timeout = 0x10000000U / wdt->rate;
+
+        /*
+         * If 'timeout-sec' unspecified in devicetree, assume a 30 second
+         * default, unless the max timeout is less than 30 seconds, then use
+         * the max instead.
+         */
+        wdt->wdd.timeout = min(wdt->wdd.max_timeout, 30U);
+        watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
+
+        ret = watchdog_register_device(&wdt->wdd);
+        if (ret) {
+                dev_err(&pdev->dev, "failed to register watchdog\n");
+                goto err_clk_unprepare;
+        }
+
+        /*
+         * WDT restart notifier has priority 0 (use as a last resort)
+         */
+        wdt->restart_nb.notifier_call = qcom_wdt_restart;
+        ret = register_restart_handler(&wdt->restart_nb);
+        if (ret)
+                dev_err(&pdev->dev, "failed to setup restart handler\n");
+
+        platform_set_drvdata(pdev, wdt);
+        return 0;
+
+err_clk_unprepare:
+        clk_disable_unprepare(wdt->clk);
+        return ret;
+}
+
+static int qcom_wdt_remove(struct platform_device *pdev)
+{
+        struct qcom_wdt *wdt = platform_get_drvdata(pdev);
+
+        unregister_restart_handler(&wdt->restart_nb);
+        watchdog_unregister_device(&wdt->wdd);
+        clk_disable_unprepare(wdt->clk);
+        return 0;
+}
+
+static const struct of_device_id qcom_wdt_of_table[] = {
+        { .compatible = "qcom,kpss-wdt-msm8960", },
+        { .compatible = "qcom,kpss-wdt-apq8064", },
+        { .compatible = "qcom,kpss-wdt-ipq8064", },
+        { },
+};
+MODULE_DEVICE_TABLE(of, qcom_wdt_of_table);
+
+static struct platform_driver qcom_watchdog_driver = {
+        .probe  = qcom_wdt_probe,
+        .remove = qcom_wdt_remove,
+        .driver = {
+                .name           = KBUILD_MODNAME,
+                .of_match_table = qcom_wdt_of_table,
+        },
+};
+module_platform_driver(qcom_watchdog_driver);
+
+MODULE_DESCRIPTION("QCOM KPSS Watchdog Driver");
+MODULE_LICENSE("GPL v2");