--- /dev/null
+/*
+ * drivers/char/watchdog/davinci_wdt.c
+ *
+ * Watchdog driver for DaVinci DM644x/DM646x processors
+ *
+ * Copyright (C) 2006-2013 Texas Instruments.
+ *
+ * 2007 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#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/err.h>
+
+#define MODULE_NAME "DAVINCI-WDT: "
+
+#define DEFAULT_HEARTBEAT 60
+#define MAX_HEARTBEAT 600 /* really the max margin is 264/27MHz*/
+
+/* Timer register set definition */
+#define PID12 (0x0)
+#define EMUMGT (0x4)
+#define TIM12 (0x10)
+#define TIM34 (0x14)
+#define PRD12 (0x18)
+#define PRD34 (0x1C)
+#define TCR (0x20)
+#define TGCR (0x24)
+#define WDTCR (0x28)
+
+/* TCR bit definitions */
+#define ENAMODE12_DISABLED (0 << 6)
+#define ENAMODE12_ONESHOT (1 << 6)
+#define ENAMODE12_PERIODIC (2 << 6)
+
+/* TGCR bit definitions */
+#define TIM12RS_UNRESET (1 << 0)
+#define TIM34RS_UNRESET (1 << 1)
+#define TIMMODE_64BIT_WDOG (2 << 2)
+
+/* WDTCR bit definitions */
+#define WDEN (1 << 14)
+#define WDFLAG (1 << 15)
+#define WDKEY_SEQ0 (0xa5c6 << 16)
+#define WDKEY_SEQ1 (0xda7e << 16)
+
+static int heartbeat;
+
+/*
+ * struct to hold data for each WDT device
+ * @base - base io address of WD device
+ * @clk - source clock of WDT
+ * @wdd - hold watchdog device as is in WDT core
+ */
+struct davinci_wdt_device {
+ void __iomem *base;
+ struct clk *clk;
+ struct watchdog_device wdd;
+};
+
+static int davinci_wdt_start(struct watchdog_device *wdd)
+{
+ u32 tgcr;
+ u32 timer_margin;
+ unsigned long wdt_freq;
+ struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
+
+ wdt_freq = clk_get_rate(davinci_wdt->clk);
+
+ /* disable, internal clock source */
+ iowrite32(0, davinci_wdt->base + TCR);
+ /* reset timer, set mode to 64-bit watchdog, and unreset */
+ iowrite32(0, davinci_wdt->base + TGCR);
+ tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
+ iowrite32(tgcr, davinci_wdt->base + TGCR);
+ /* clear counter regs */
+ iowrite32(0, davinci_wdt->base + TIM12);
+ iowrite32(0, davinci_wdt->base + TIM34);
+ /* set timeout period */
+ timer_margin = (((u64)wdd->timeout * wdt_freq) & 0xffffffff);
+ iowrite32(timer_margin, davinci_wdt->base + PRD12);
+ timer_margin = (((u64)wdd->timeout * wdt_freq) >> 32);
+ iowrite32(timer_margin, davinci_wdt->base + PRD34);
+ /* enable run continuously */
+ iowrite32(ENAMODE12_PERIODIC, davinci_wdt->base + TCR);
+ /* Once the WDT is in pre-active state write to
+ * TIM12, TIM34, PRD12, PRD34, TCR, TGCR, WDTCR are
+ * write protected (except for the WDKEY field)
+ */
+ /* put watchdog in pre-active state */
+ iowrite32(WDKEY_SEQ0 | WDEN, davinci_wdt->base + WDTCR);
+ /* put watchdog in active state */
+ iowrite32(WDKEY_SEQ1 | WDEN, davinci_wdt->base + WDTCR);
+ return 0;
+}
+
+static int davinci_wdt_ping(struct watchdog_device *wdd)
+{
+ struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
+
+ /* put watchdog in service state */
+ iowrite32(WDKEY_SEQ0, davinci_wdt->base + WDTCR);
+ /* put watchdog in active state */
+ iowrite32(WDKEY_SEQ1, davinci_wdt->base + WDTCR);
+ return 0;
+}
+
+static unsigned int davinci_wdt_get_timeleft(struct watchdog_device *wdd)
+{
+ u64 timer_counter;
+ unsigned long freq;
+ u32 val;
+ struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
+
+ /* if timeout has occured then return 0 */
+ val = ioread32(davinci_wdt->base + WDTCR);
+ if (val & WDFLAG)
+ return 0;
+
+ freq = clk_get_rate(davinci_wdt->clk);
+
+ if (!freq)
+ return 0;
+
+ timer_counter = ioread32(davinci_wdt->base + TIM12);
+ timer_counter |= ((u64)ioread32(davinci_wdt->base + TIM34) << 32);
+
+ do_div(timer_counter, freq);
+
+ return wdd->timeout - timer_counter;
+}
+
+static const struct watchdog_info davinci_wdt_info = {
+ .options = WDIOF_KEEPALIVEPING,
+ .identity = "DaVinci/Keystone Watchdog",
+};
+
+static const struct watchdog_ops davinci_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = davinci_wdt_start,
+ .stop = davinci_wdt_ping,
+ .ping = davinci_wdt_ping,
+ .get_timeleft = davinci_wdt_get_timeleft,
+};
+
+static int davinci_wdt_probe(struct platform_device *pdev)
+{
+ int ret = 0;
+ struct device *dev = &pdev->dev;
+ struct resource *wdt_mem;
+ struct watchdog_device *wdd;
+ struct davinci_wdt_device *davinci_wdt;
+
+ davinci_wdt = devm_kzalloc(dev, sizeof(*davinci_wdt), GFP_KERNEL);
+ if (!davinci_wdt)
+ return -ENOMEM;
+
+ davinci_wdt->clk = devm_clk_get(dev, NULL);
+ if (WARN_ON(IS_ERR(davinci_wdt->clk)))
+ return PTR_ERR(davinci_wdt->clk);
+
+ clk_prepare_enable(davinci_wdt->clk);
+
+ platform_set_drvdata(pdev, davinci_wdt);
+
+ wdd = &davinci_wdt->wdd;
+ wdd->info = &davinci_wdt_info;
+ wdd->ops = &davinci_wdt_ops;
+ wdd->min_timeout = 1;
+ wdd->max_timeout = MAX_HEARTBEAT;
+ wdd->timeout = DEFAULT_HEARTBEAT;
+
+ watchdog_init_timeout(wdd, heartbeat, dev);
+
+ dev_info(dev, "heartbeat %d sec\n", wdd->timeout);
+
+ watchdog_set_drvdata(wdd, davinci_wdt);
+ watchdog_set_nowayout(wdd, 1);
+
+ wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ davinci_wdt->base = devm_ioremap_resource(dev, wdt_mem);
+ if (IS_ERR(davinci_wdt->base))
+ return PTR_ERR(davinci_wdt->base);
+
+ ret = watchdog_register_device(wdd);
+ if (ret < 0)
+ dev_err(dev, "cannot register watchdog device\n");
+
+ return ret;
+}
+
+static int davinci_wdt_remove(struct platform_device *pdev)
+{
+ struct davinci_wdt_device *davinci_wdt = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&davinci_wdt->wdd);
+ clk_disable_unprepare(davinci_wdt->clk);
+
+ return 0;
+}
+
+static const struct of_device_id davinci_wdt_of_match[] = {
+ { .compatible = "ti,davinci-wdt", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, davinci_wdt_of_match);
+
+static struct platform_driver platform_wdt_driver = {
+ .driver = {
+ .name = "davinci-wdt",
+ .of_match_table = davinci_wdt_of_match,
+ },
+ .probe = davinci_wdt_probe,
+ .remove = davinci_wdt_remove,
+};
+
+module_platform_driver(platform_wdt_driver);
+
+MODULE_AUTHOR("Texas Instruments");
+MODULE_DESCRIPTION("DaVinci Watchdog Driver");
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+ "Watchdog heartbeat period in seconds from 1 to "
+ __MODULE_STRING(MAX_HEARTBEAT) ", default "
+ __MODULE_STRING(DEFAULT_HEARTBEAT));
+
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:davinci-wdt");
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