--- /dev/null
+/*
+ * Watchdog driver for Cortina Systems Gemini SoC
+ *
+ * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Inspired by the out-of-tree drivers from OpenWRT:
+ * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
+ *
+ * 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/watchdog.h>
+
+#define GEMINI_WDCOUNTER 0x0
+#define GEMINI_WDLOAD 0x4
+#define GEMINI_WDRESTART 0x8
+#define GEMINI_WDCR 0xC
+
+#define WDRESTART_MAGIC 0x5AB9
+
+#define WDCR_CLOCK_5MHZ BIT(4)
+#define WDCR_SYS_RST BIT(1)
+#define WDCR_ENABLE BIT(0)
+
+#define WDT_CLOCK 5000000 /* 5 MHz */
+
+struct gemini_wdt {
+ struct watchdog_device wdd;
+ struct device *dev;
+ void __iomem *base;
+};
+
+static inline
+struct gemini_wdt *to_gemini_wdt(struct watchdog_device *wdd)
+{
+ return container_of(wdd, struct gemini_wdt, wdd);
+}
+
+static int gemini_wdt_start(struct watchdog_device *wdd)
+{
+ struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
+
+ writel(wdd->timeout * WDT_CLOCK, gwdt->base + GEMINI_WDLOAD);
+ writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);
+ /* set clock before enabling */
+ writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,
+ gwdt->base + GEMINI_WDCR);
+ writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,
+ gwdt->base + GEMINI_WDCR);
+
+ return 0;
+}
+
+static int gemini_wdt_stop(struct watchdog_device *wdd)
+{
+ struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
+
+ writel(0, gwdt->base + GEMINI_WDCR);
+
+ return 0;
+}
+
+static int gemini_wdt_ping(struct watchdog_device *wdd)
+{
+ struct gemini_wdt *gwdt = to_gemini_wdt(wdd);
+
+ writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);
+
+ return 0;
+}
+
+static int gemini_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
+{
+ wdd->timeout = timeout;
+ if (watchdog_active(wdd))
+ gemini_wdt_start(wdd);
+
+ return 0;
+}
+
+static irqreturn_t gemini_wdt_interrupt(int irq, void *data)
+{
+ struct gemini_wdt *gwdt = data;
+
+ watchdog_notify_pretimeout(&gwdt->wdd);
+
+ return IRQ_HANDLED;
+}
+
+static const struct watchdog_ops gemini_wdt_ops = {
+ .start = gemini_wdt_start,
+ .stop = gemini_wdt_stop,
+ .ping = gemini_wdt_ping,
+ .set_timeout = gemini_wdt_set_timeout,
+ .owner = THIS_MODULE,
+};
+
+static const struct watchdog_info gemini_wdt_info = {
+ .options = WDIOF_KEEPALIVEPING
+ | WDIOF_MAGICCLOSE
+ | WDIOF_SETTIMEOUT,
+ .identity = KBUILD_MODNAME,
+};
+
+
+static int gemini_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct gemini_wdt *gwdt;
+ unsigned int reg;
+ int irq;
+ int ret;
+
+ gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);
+ if (!gwdt)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ gwdt->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(gwdt->base))
+ return PTR_ERR(gwdt->base);
+
+ irq = platform_get_irq(pdev, 0);
+ if (!irq)
+ return -EINVAL;
+
+ gwdt->dev = dev;
+ gwdt->wdd.info = &gemini_wdt_info;
+ gwdt->wdd.ops = &gemini_wdt_ops;
+ gwdt->wdd.min_timeout = 1;
+ gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;
+ gwdt->wdd.parent = dev;
+
+ /*
+ * If 'timeout-sec' unspecified in devicetree, assume a 13 second
+ * default.
+ */
+ gwdt->wdd.timeout = 13U;
+ watchdog_init_timeout(&gwdt->wdd, 0, dev);
+
+ reg = readw(gwdt->base + GEMINI_WDCR);
+ if (reg & WDCR_ENABLE) {
+ /* Watchdog was enabled by the bootloader, disable it. */
+ reg &= ~WDCR_ENABLE;
+ writel(reg, gwdt->base + GEMINI_WDCR);
+ }
+
+ ret = devm_request_irq(dev, irq, gemini_wdt_interrupt, 0,
+ "watchdog bark", gwdt);
+ if (ret)
+ return ret;
+
+ ret = devm_watchdog_register_device(dev, &gwdt->wdd);
+ if (ret) {
+ dev_err(&pdev->dev, "failed to register watchdog\n");
+ return ret;
+ }
+
+ /* Set up platform driver data */
+ platform_set_drvdata(pdev, gwdt);
+ dev_info(dev, "Gemini watchdog driver enabled\n");
+
+ return 0;
+}
+
+static int __maybe_unused gemini_wdt_suspend(struct device *dev)
+{
+ struct gemini_wdt *gwdt = dev_get_drvdata(dev);
+ unsigned int reg;
+
+ reg = readw(gwdt->base + GEMINI_WDCR);
+ reg &= ~WDCR_ENABLE;
+ writel(reg, gwdt->base + GEMINI_WDCR);
+
+ return 0;
+}
+
+static int __maybe_unused gemini_wdt_resume(struct device *dev)
+{
+ struct gemini_wdt *gwdt = dev_get_drvdata(dev);
+ unsigned int reg;
+
+ if (watchdog_active(&gwdt->wdd)) {
+ reg = readw(gwdt->base + GEMINI_WDCR);
+ reg |= WDCR_ENABLE;
+ writel(reg, gwdt->base + GEMINI_WDCR);
+ }
+
+ return 0;
+}
+
+static const struct dev_pm_ops gemini_wdt_dev_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(gemini_wdt_suspend,
+ gemini_wdt_resume)
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id gemini_wdt_match[] = {
+ { .compatible = "cortina,gemini-watchdog" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, gemini_wdt_match);
+#endif
+
+static struct platform_driver gemini_wdt_driver = {
+ .probe = gemini_wdt_probe,
+ .driver = {
+ .name = "gemini-wdt",
+ .of_match_table = of_match_ptr(gemini_wdt_match),
+ .pm = &gemini_wdt_dev_pm_ops,
+ },
+};
+module_platform_driver(gemini_wdt_driver);
+MODULE_AUTHOR("Linus Walleij");
+MODULE_DESCRIPTION("Watchdog driver for Gemini");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-exynos.git / commitdiff