--- /dev/null
+/*
+ * Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
+ * JZ4740 Watchdog driver
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/device.h>
+#include <linux/clk.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/of.h>
+
+#include <asm/mach-jz4740/timer.h>
+
+#define JZ_REG_WDT_TIMER_DATA 0x0
+#define JZ_REG_WDT_COUNTER_ENABLE 0x4
+#define JZ_REG_WDT_TIMER_COUNTER 0x8
+#define JZ_REG_WDT_TIMER_CONTROL 0xC
+
+#define JZ_WDT_CLOCK_PCLK 0x1
+#define JZ_WDT_CLOCK_RTC 0x2
+#define JZ_WDT_CLOCK_EXT 0x4
+
+#define JZ_WDT_CLOCK_DIV_SHIFT 3
+
+#define JZ_WDT_CLOCK_DIV_1 (0 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_4 (1 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_16 (2 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_64 (3 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_256 (4 << JZ_WDT_CLOCK_DIV_SHIFT)
+#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
+
+#define DEFAULT_HEARTBEAT 5
+#define MAX_HEARTBEAT 2048
+
+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) ")");
+
+static unsigned int heartbeat = DEFAULT_HEARTBEAT;
+module_param(heartbeat, uint, 0);
+MODULE_PARM_DESC(heartbeat,
+ "Watchdog heartbeat period in seconds from 1 to "
+ __MODULE_STRING(MAX_HEARTBEAT) ", default "
+ __MODULE_STRING(DEFAULT_HEARTBEAT));
+
+struct jz4740_wdt_drvdata {
+ struct watchdog_device wdt;
+ void __iomem *base;
+ struct clk *rtc_clk;
+};
+
+static int jz4740_wdt_ping(struct watchdog_device *wdt_dev)
+{
+ struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+ writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
+ return 0;
+}
+
+static int jz4740_wdt_set_timeout(struct watchdog_device *wdt_dev,
+ unsigned int new_timeout)
+{
+ struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+ unsigned int rtc_clk_rate;
+ unsigned int timeout_value;
+ unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
+
+ rtc_clk_rate = clk_get_rate(drvdata->rtc_clk);
+
+ timeout_value = rtc_clk_rate * new_timeout;
+ while (timeout_value > 0xffff) {
+ if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
+ /* Requested timeout too high;
+ * use highest possible value. */
+ timeout_value = 0xffff;
+ break;
+ }
+ timeout_value >>= 2;
+ clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
+ }
+
+ writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
+ writew(clock_div, drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
+
+ writew((u16)timeout_value, drvdata->base + JZ_REG_WDT_TIMER_DATA);
+ writew(0x0, drvdata->base + JZ_REG_WDT_TIMER_COUNTER);
+ writew(clock_div | JZ_WDT_CLOCK_RTC,
+ drvdata->base + JZ_REG_WDT_TIMER_CONTROL);
+
+ writeb(0x1, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
+
+ wdt_dev->timeout = new_timeout;
+ return 0;
+}
+
+static int jz4740_wdt_start(struct watchdog_device *wdt_dev)
+{
+ jz4740_timer_enable_watchdog();
+ jz4740_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
+
+ return 0;
+}
+
+static int jz4740_wdt_stop(struct watchdog_device *wdt_dev)
+{
+ struct jz4740_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+ jz4740_timer_disable_watchdog();
+ writeb(0x0, drvdata->base + JZ_REG_WDT_COUNTER_ENABLE);
+
+ return 0;
+}
+
+static const struct watchdog_info jz4740_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+ .identity = "jz4740 Watchdog",
+};
+
+static const struct watchdog_ops jz4740_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = jz4740_wdt_start,
+ .stop = jz4740_wdt_stop,
+ .ping = jz4740_wdt_ping,
+ .set_timeout = jz4740_wdt_set_timeout,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id jz4740_wdt_of_matches[] = {
+ { .compatible = "ingenic,jz4740-watchdog", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, jz4740_wdt_of_matches)
+#endif
+
+static int jz4740_wdt_probe(struct platform_device *pdev)
+{
+ struct jz4740_wdt_drvdata *drvdata;
+ struct watchdog_device *jz4740_wdt;
+ struct resource *res;
+ int ret;
+
+ drvdata = devm_kzalloc(&pdev->dev, sizeof(struct jz4740_wdt_drvdata),
+ GFP_KERNEL);
+ if (!drvdata) {
+ dev_err(&pdev->dev, "Unable to alloacate watchdog device\n");
+ return -ENOMEM;
+ }
+
+ if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
+ heartbeat = DEFAULT_HEARTBEAT;
+
+ jz4740_wdt = &drvdata->wdt;
+ jz4740_wdt->info = &jz4740_wdt_info;
+ jz4740_wdt->ops = &jz4740_wdt_ops;
+ jz4740_wdt->timeout = heartbeat;
+ jz4740_wdt->min_timeout = 1;
+ jz4740_wdt->max_timeout = MAX_HEARTBEAT;
+ watchdog_set_nowayout(jz4740_wdt, nowayout);
+ watchdog_set_drvdata(jz4740_wdt, drvdata);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ drvdata->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(drvdata->base)) {
+ ret = PTR_ERR(drvdata->base);
+ goto err_out;
+ }
+
+ drvdata->rtc_clk = clk_get(&pdev->dev, "rtc");
+ if (IS_ERR(drvdata->rtc_clk)) {
+ dev_err(&pdev->dev, "cannot find RTC clock\n");
+ ret = PTR_ERR(drvdata->rtc_clk);
+ goto err_out;
+ }
+
+ ret = watchdog_register_device(&drvdata->wdt);
+ if (ret < 0)
+ goto err_disable_clk;
+
+ platform_set_drvdata(pdev, drvdata);
+ return 0;
+
+err_disable_clk:
+ clk_put(drvdata->rtc_clk);
+err_out:
+ return ret;
+}
+
+static int jz4740_wdt_remove(struct platform_device *pdev)
+{
+ struct jz4740_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
+
+ jz4740_wdt_stop(&drvdata->wdt);
+ watchdog_unregister_device(&drvdata->wdt);
+ clk_put(drvdata->rtc_clk);
+
+ return 0;
+}
+
+static struct platform_driver jz4740_wdt_driver = {
+ .probe = jz4740_wdt_probe,
+ .remove = jz4740_wdt_remove,
+ .driver = {
+ .name = "jz4740-wdt",
+ .of_match_table = of_match_ptr(jz4740_wdt_of_matches),
+ },
+};
+
+module_platform_driver(jz4740_wdt_driver);
+
+MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
+MODULE_DESCRIPTION("jz4740 Watchdog Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:jz4740-wdt");
Code Review / kvmfornfv.git / blobdiff