diff options
Diffstat (limited to 'drivers/watchdog/jz4740_wdt.c')
| -rw-r--r-- | drivers/watchdog/jz4740_wdt.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/drivers/watchdog/jz4740_wdt.c b/drivers/watchdog/jz4740_wdt.c new file mode 100644 index 00000000..978615ef --- /dev/null +++ b/drivers/watchdog/jz4740_wdt.c @@ -0,0 +1,226 @@ +/* + * 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/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/init.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 <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, +}; + +static int __devinit 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_request_and_ioremap(&pdev->dev, res); + if (drvdata->base == NULL) { + ret = -EBUSY; + goto err_out; + } + + drvdata->rtc_clk = clk_get(NULL, "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 __devexit 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 = __devexit_p(jz4740_wdt_remove), + .driver = { + .name = "jz4740-wdt", + .owner = THIS_MODULE, + }, +}; + +module_platform_driver(jz4740_wdt_driver); + +MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>"); +MODULE_DESCRIPTION("jz4740 Watchdog Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); +MODULE_ALIAS("platform:jz4740-wdt"); |