1 files changed, 289 insertions, 0 deletions

diff --git a/drivers/watchdog/imgpdc_wdt.c b/drivers/watchdog/imgpdc_wdt.c
new file mode 100644
index 000000000000..c8def68d9e4c
--- /dev/null
+++ b/drivers/watchdog/imgpdc_wdt.c
@@ -0,0 +1,289 @@
+/*
+ * Imagination Technologies PowerDown Controller Watchdog Timer.
+ *
+ * Copyright (c) 2014 Imagination Technologies Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * Based on drivers/watchdog/sunxi_wdt.c Copyright (c) 2013 Carlo Caione
+ *                                                     2012 Henrik Nordstrom
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/watchdog.h>
+
+/* registers */
+#define PDC_WDT_SOFT_RESET              0x00
+#define PDC_WDT_CONFIG                  0x04
+  #define PDC_WDT_CONFIG_ENABLE         BIT(31)
+  #define PDC_WDT_CONFIG_DELAY_MASK     0x1f
+
+#define PDC_WDT_TICKLE1                 0x08
+#define PDC_WDT_TICKLE1_MAGIC           0xabcd1234
+#define PDC_WDT_TICKLE2                 0x0c
+#define PDC_WDT_TICKLE2_MAGIC           0x4321dcba
+
+#define PDC_WDT_TICKLE_STATUS_MASK      0x7
+#define PDC_WDT_TICKLE_STATUS_SHIFT     0
+#define PDC_WDT_TICKLE_STATUS_HRESET    0x0  /* Hard reset */
+#define PDC_WDT_TICKLE_STATUS_TIMEOUT   0x1  /* Timeout */
+#define PDC_WDT_TICKLE_STATUS_TICKLE    0x2  /* Tickled incorrectly */
+#define PDC_WDT_TICKLE_STATUS_SRESET    0x3  /* Soft reset */
+#define PDC_WDT_TICKLE_STATUS_USER      0x4  /* User reset */
+
+/* Timeout values are in seconds */
+#define PDC_WDT_MIN_TIMEOUT             1
+#define PDC_WDT_DEF_TIMEOUT             64
+
+static int heartbeat;
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
+        "(default = " __MODULE_STRING(PDC_WDT_DEF_TIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+        "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct pdc_wdt_dev {
+        struct watchdog_device wdt_dev;
+        struct clk *wdt_clk;
+        struct clk *sys_clk;
+        void __iomem *base;
+};
+
+static int pdc_wdt_keepalive(struct watchdog_device *wdt_dev)
+{
+        struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
+
+        writel(PDC_WDT_TICKLE1_MAGIC, wdt->base + PDC_WDT_TICKLE1);
+        writel(PDC_WDT_TICKLE2_MAGIC, wdt->base + PDC_WDT_TICKLE2);
+
+        return 0;
+}
+
+static int pdc_wdt_stop(struct watchdog_device *wdt_dev)
+{
+        unsigned int val;
+        struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
+
+        val = readl(wdt->base + PDC_WDT_CONFIG);
+        val &= ~PDC_WDT_CONFIG_ENABLE;
+        writel(val, wdt->base + PDC_WDT_CONFIG);
+
+        /* Must tickle to finish the stop */
+        pdc_wdt_keepalive(wdt_dev);
+
+        return 0;
+}
+
+static int pdc_wdt_set_timeout(struct watchdog_device *wdt_dev,
+                               unsigned int new_timeout)
+{
+        unsigned int val;
+        struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
+        unsigned long clk_rate = clk_get_rate(wdt->wdt_clk);
+
+        wdt->wdt_dev.timeout = new_timeout;
+
+        val = readl(wdt->base + PDC_WDT_CONFIG) & ~PDC_WDT_CONFIG_DELAY_MASK;
+        val |= order_base_2(new_timeout * clk_rate) - 1;
+        writel(val, wdt->base + PDC_WDT_CONFIG);
+
+        return 0;
+}
+
+/* Start the watchdog timer (delay should already be set) */
+static int pdc_wdt_start(struct watchdog_device *wdt_dev)
+{
+        unsigned int val;
+        struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
+
+        val = readl(wdt->base + PDC_WDT_CONFIG);
+        val |= PDC_WDT_CONFIG_ENABLE;
+        writel(val, wdt->base + PDC_WDT_CONFIG);
+
+        return 0;
+}
+
+static struct watchdog_info pdc_wdt_info = {
+        .identity       = "IMG PDC Watchdog",
+        .options        = WDIOF_SETTIMEOUT |
+                          WDIOF_KEEPALIVEPING |
+                          WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops pdc_wdt_ops = {
+        .owner          = THIS_MODULE,
+        .start          = pdc_wdt_start,
+        .stop           = pdc_wdt_stop,
+        .ping           = pdc_wdt_keepalive,
+        .set_timeout    = pdc_wdt_set_timeout,
+};
+
+static int pdc_wdt_probe(struct platform_device *pdev)
+{
+        int ret, val;
+        unsigned long clk_rate;
+        struct resource *res;
+        struct pdc_wdt_dev *pdc_wdt;
+
+        pdc_wdt = devm_kzalloc(&pdev->dev, sizeof(*pdc_wdt), GFP_KERNEL);
+        if (!pdc_wdt)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        pdc_wdt->base = devm_ioremap_resource(&pdev->dev, res);
+        if (IS_ERR(pdc_wdt->base))
+                return PTR_ERR(pdc_wdt->base);
+
+        pdc_wdt->sys_clk = devm_clk_get(&pdev->dev, "sys");
+        if (IS_ERR(pdc_wdt->sys_clk)) {
+                dev_err(&pdev->dev, "failed to get the sys clock\n");
+                return PTR_ERR(pdc_wdt->sys_clk);
+        }
+
+        pdc_wdt->wdt_clk = devm_clk_get(&pdev->dev, "wdt");
+        if (IS_ERR(pdc_wdt->wdt_clk)) {
+                dev_err(&pdev->dev, "failed to get the wdt clock\n");
+                return PTR_ERR(pdc_wdt->wdt_clk);
+        }
+
+        ret = clk_prepare_enable(pdc_wdt->sys_clk);
+        if (ret) {
+                dev_err(&pdev->dev, "could not prepare or enable sys clock\n");
+                return ret;
+        }
+
+        ret = clk_prepare_enable(pdc_wdt->wdt_clk);
+        if (ret) {
+                dev_err(&pdev->dev, "could not prepare or enable wdt clock\n");
+                goto disable_sys_clk;
+        }
+
+        /* We use the clock rate to calculate the max timeout */
+        clk_rate = clk_get_rate(pdc_wdt->wdt_clk);
+        if (clk_rate == 0) {
+                dev_err(&pdev->dev, "failed to get clock rate\n");
+                ret = -EINVAL;
+                goto disable_wdt_clk;
+        }
+
+        if (order_base_2(clk_rate) > PDC_WDT_CONFIG_DELAY_MASK + 1) {
+                dev_err(&pdev->dev, "invalid clock rate\n");
+                ret = -EINVAL;
+                goto disable_wdt_clk;
+        }
+
+        if (order_base_2(clk_rate) == 0)
+                pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT + 1;
+        else
+                pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT;
+
+        pdc_wdt->wdt_dev.info = &pdc_wdt_info;
+        pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
+        pdc_wdt->wdt_dev.max_timeout = 1 << PDC_WDT_CONFIG_DELAY_MASK;
+        pdc_wdt->wdt_dev.parent = &pdev->dev;
+
+        ret = watchdog_init_timeout(&pdc_wdt->wdt_dev, heartbeat, &pdev->dev);
+        if (ret < 0) {
+                pdc_wdt->wdt_dev.timeout = pdc_wdt->wdt_dev.max_timeout;
+                dev_warn(&pdev->dev,
+                         "Initial timeout out of range! setting max timeout\n");
+        }
+
+        pdc_wdt_stop(&pdc_wdt->wdt_dev);
+
+        /* Find what caused the last reset */
+        val = readl(pdc_wdt->base + PDC_WDT_TICKLE1);
+        val = (val & PDC_WDT_TICKLE_STATUS_MASK) >> PDC_WDT_TICKLE_STATUS_SHIFT;
+        switch (val) {
+        case PDC_WDT_TICKLE_STATUS_TICKLE:
+        case PDC_WDT_TICKLE_STATUS_TIMEOUT:
+                pdc_wdt->wdt_dev.bootstatus |= WDIOF_CARDRESET;
+                dev_info(&pdev->dev,
+                         "watchdog module last reset due to timeout\n");
+                break;
+        case PDC_WDT_TICKLE_STATUS_HRESET:
+                dev_info(&pdev->dev,
+                         "watchdog module last reset due to hard reset\n");
+                break;
+        case PDC_WDT_TICKLE_STATUS_SRESET:
+                dev_info(&pdev->dev,
+                         "watchdog module last reset due to soft reset\n");
+                break;
+        case PDC_WDT_TICKLE_STATUS_USER:
+                dev_info(&pdev->dev,
+                         "watchdog module last reset due to user reset\n");
+                break;
+        default:
+                dev_info(&pdev->dev,
+                         "contains an illegal status code (%08x)\n", val);
+                break;
+        }
+
+        watchdog_set_nowayout(&pdc_wdt->wdt_dev, nowayout);
+
+        platform_set_drvdata(pdev, pdc_wdt);
+        watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
+
+        ret = watchdog_register_device(&pdc_wdt->wdt_dev);
+        if (ret)
+                goto disable_wdt_clk;
+
+        return 0;
+
+disable_wdt_clk:
+        clk_disable_unprepare(pdc_wdt->wdt_clk);
+disable_sys_clk:
+        clk_disable_unprepare(pdc_wdt->sys_clk);
+        return ret;
+}
+
+static void pdc_wdt_shutdown(struct platform_device *pdev)
+{
+        struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
+
+        pdc_wdt_stop(&pdc_wdt->wdt_dev);
+}
+
+static int pdc_wdt_remove(struct platform_device *pdev)
+{
+        struct pdc_wdt_dev *pdc_wdt = platform_get_drvdata(pdev);
+
+        pdc_wdt_stop(&pdc_wdt->wdt_dev);
+        watchdog_unregister_device(&pdc_wdt->wdt_dev);
+        clk_disable_unprepare(pdc_wdt->wdt_clk);
+        clk_disable_unprepare(pdc_wdt->sys_clk);
+
+        return 0;
+}
+
+static const struct of_device_id pdc_wdt_match[] = {
+        { .compatible = "img,pdc-wdt" },
+        {}
+};
+MODULE_DEVICE_TABLE(of, pdc_wdt_match);
+
+static struct platform_driver pdc_wdt_driver = {
+        .driver = {
+                .name = "imgpdc-wdt",
+                .of_match_table = pdc_wdt_match,
+        },
+        .probe = pdc_wdt_probe,
+        .remove = pdc_wdt_remove,
+        .shutdown = pdc_wdt_shutdown,
+};
+module_platform_driver(pdc_wdt_driver);
+
+MODULE_AUTHOR("Jude Abraham <Jude.Abraham@imgtec.com>");
+MODULE_AUTHOR("Naidu Tellapati <Naidu.Tellapati@imgtec.com>");
+MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
+MODULE_LICENSE("GPL v2");