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path: root/drivers/watchdog/atlas7_wdt.c
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Diffstat (limited to 'drivers/watchdog/atlas7_wdt.c')
-rw-r--r--drivers/watchdog/atlas7_wdt.c242
1 files changed, 242 insertions, 0 deletions
diff --git a/drivers/watchdog/atlas7_wdt.c b/drivers/watchdog/atlas7_wdt.c
new file mode 100644
index 000000000000..df6d9242a319
--- /dev/null
+++ b/drivers/watchdog/atlas7_wdt.c
@@ -0,0 +1,242 @@
+/*
+ * Watchdog driver for CSR Atlas7
+ *
+ * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2.
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+#define ATLAS7_TIMER_WDT_INDEX 5
+#define ATLAS7_WDT_DEFAULT_TIMEOUT 20
+
+#define ATLAS7_WDT_CNT_CTRL (0 + 4 * ATLAS7_TIMER_WDT_INDEX)
+#define ATLAS7_WDT_CNT_MATCH (0x18 + 4 * ATLAS7_TIMER_WDT_INDEX)
+#define ATLAS7_WDT_CNT (0x48 + 4 * ATLAS7_TIMER_WDT_INDEX)
+#define ATLAS7_WDT_CNT_EN (BIT(0) | BIT(1))
+#define ATLAS7_WDT_EN 0x64
+
+static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT;
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+module_param(timeout, uint, 0);
+module_param(nowayout, bool, 0);
+
+MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct atlas7_wdog {
+ struct device *dev;
+ void __iomem *base;
+ unsigned long tick_rate;
+ struct clk *clk;
+};
+
+static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+ u32 counter, match, delta;
+
+ counter = readl(wdt->base + ATLAS7_WDT_CNT);
+ match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH);
+ delta = match - counter;
+
+ return delta / wdt->tick_rate;
+}
+
+static int atlas7_wdt_ping(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+ u32 counter, match, delta;
+
+ counter = readl(wdt->base + ATLAS7_WDT_CNT);
+ delta = wdd->timeout * wdt->tick_rate;
+ match = counter + delta;
+
+ writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH);
+
+ return 0;
+}
+
+static int atlas7_wdt_enable(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+
+ atlas7_wdt_ping(wdd);
+
+ writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) | ATLAS7_WDT_CNT_EN,
+ wdt->base + ATLAS7_WDT_CNT_CTRL);
+ writel(1, wdt->base + ATLAS7_WDT_EN);
+
+ return 0;
+}
+
+static int atlas7_wdt_disable(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+
+ writel(0, wdt->base + ATLAS7_WDT_EN);
+ writel(readl(wdt->base + ATLAS7_WDT_CNT_CTRL) & ~ATLAS7_WDT_CNT_EN,
+ wdt->base + ATLAS7_WDT_CNT_CTRL);
+
+ return 0;
+}
+
+static int atlas7_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
+{
+ wdd->timeout = to;
+
+ return 0;
+}
+
+#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
+
+static const struct watchdog_info atlas7_wdt_ident = {
+ .options = OPTIONS,
+ .firmware_version = 0,
+ .identity = "atlas7 Watchdog",
+};
+
+static struct watchdog_ops atlas7_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = atlas7_wdt_enable,
+ .stop = atlas7_wdt_disable,
+ .get_timeleft = atlas7_wdt_gettimeleft,
+ .ping = atlas7_wdt_ping,
+ .set_timeout = atlas7_wdt_settimeout,
+};
+
+static struct watchdog_device atlas7_wdd = {
+ .info = &atlas7_wdt_ident,
+ .ops = &atlas7_wdt_ops,
+ .timeout = ATLAS7_WDT_DEFAULT_TIMEOUT,
+};
+
+static const struct of_device_id atlas7_wdt_ids[] = {
+ { .compatible = "sirf,atlas7-tick"},
+ {}
+};
+
+static int atlas7_wdt_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct atlas7_wdog *wdt;
+ struct resource *res;
+ struct clk *clk;
+ 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);
+
+ clk = of_clk_get(np, 0);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+ ret = clk_prepare_enable(clk);
+ if (ret) {
+ dev_err(&pdev->dev, "clk enable failed\n");
+ goto err;
+ }
+
+ /* disable watchdog hardware */
+ writel(0, wdt->base + ATLAS7_WDT_CNT_CTRL);
+
+ wdt->tick_rate = clk_get_rate(clk);
+ wdt->clk = clk;
+ atlas7_wdd.min_timeout = 1;
+ atlas7_wdd.max_timeout = UINT_MAX / wdt->tick_rate;
+
+ watchdog_init_timeout(&atlas7_wdd, 0, &pdev->dev);
+ watchdog_set_nowayout(&atlas7_wdd, nowayout);
+
+ watchdog_set_drvdata(&atlas7_wdd, wdt);
+ platform_set_drvdata(pdev, &atlas7_wdd);
+
+ ret = watchdog_register_device(&atlas7_wdd);
+ if (ret)
+ goto err1;
+
+ return 0;
+
+err1:
+ clk_disable_unprepare(clk);
+err:
+ clk_put(clk);
+ return ret;
+}
+
+static void atlas7_wdt_shutdown(struct platform_device *pdev)
+{
+ struct watchdog_device *wdd = platform_get_drvdata(pdev);
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+
+ atlas7_wdt_disable(wdd);
+ clk_disable_unprepare(wdt->clk);
+}
+
+static int atlas7_wdt_remove(struct platform_device *pdev)
+{
+ struct watchdog_device *wdd = platform_get_drvdata(pdev);
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+
+ atlas7_wdt_shutdown(pdev);
+ clk_put(wdt->clk);
+ return 0;
+}
+
+static int __maybe_unused atlas7_wdt_suspend(struct device *dev)
+{
+ /*
+ * NOTE:timer controller registers settings are saved
+ * and restored back by the timer-atlas7.c
+ */
+ return 0;
+}
+
+static int __maybe_unused atlas7_wdt_resume(struct device *dev)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ /*
+ * NOTE: Since timer controller registers settings are saved
+ * and restored back by the timer-atlas7.c, so we need not
+ * update WD settings except refreshing timeout.
+ */
+ atlas7_wdt_ping(wdd);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(atlas7_wdt_pm_ops,
+ atlas7_wdt_suspend, atlas7_wdt_resume);
+
+MODULE_DEVICE_TABLE(of, atlas7_wdt_ids);
+
+static struct platform_driver atlas7_wdt_driver = {
+ .driver = {
+ .name = "atlas7-wdt",
+ .pm = &atlas7_wdt_pm_ops,
+ .of_match_table = atlas7_wdt_ids,
+ },
+ .probe = atlas7_wdt_probe,
+ .remove = atlas7_wdt_remove,
+ .shutdown = atlas7_wdt_shutdown,
+};
+module_platform_driver(atlas7_wdt_driver);
+
+MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
+MODULE_AUTHOR("Guo Zeng <Guo.Zeng@csr.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:atlas7-wdt");