/* * 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; wdd->parent = &pdev->dev; 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");