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| 1 | +/* |
| 2 | + * Watchdog driver for Broadcom BCM2835 |
| 3 | + * |
| 4 | + * "bcm2708_wdog" driver written by Luke Diamand that was obtained from |
| 5 | + * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used |
| 6 | + * as a hardware reference for the Broadcom BCM2835 watchdog timer. |
| 7 | + * |
| 8 | + * Copyright (C) 2013 Lubomir Rintel <[email protected]> |
| 9 | + * |
| 10 | + * This program is free software; you can redistribute it and/or modify it |
| 11 | + * under the terms of the GNU General Public License as published by the |
| 12 | + * Free Software Foundation; either version 2 of the License, or (at your |
| 13 | + * option) any later version. |
| 14 | + */ |
| 15 | + |
| 16 | +#include <linux/types.h> |
| 17 | +#include <linux/module.h> |
| 18 | +#include <linux/io.h> |
| 19 | +#include <linux/watchdog.h> |
| 20 | +#include <linux/platform_device.h> |
| 21 | +#include <linux/of_address.h> |
| 22 | +#include <linux/miscdevice.h> |
| 23 | + |
| 24 | +#define PM_RSTC 0x1c |
| 25 | +#define PM_WDOG 0x24 |
| 26 | + |
| 27 | +#define PM_PASSWORD 0x5a000000 |
| 28 | + |
| 29 | +#define PM_WDOG_TIME_SET 0x000fffff |
| 30 | +#define PM_RSTC_WRCFG_CLR 0xffffffcf |
| 31 | +#define PM_RSTC_WRCFG_SET 0x00000030 |
| 32 | +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 |
| 33 | +#define PM_RSTC_RESET 0x00000102 |
| 34 | + |
| 35 | +#define SECS_TO_WDOG_TICKS(x) ((x) << 16) |
| 36 | +#define WDOG_TICKS_TO_SECS(x) ((x) >> 16) |
| 37 | + |
| 38 | +struct bcm2835_wdt { |
| 39 | + void __iomem *base; |
| 40 | + spinlock_t lock; |
| 41 | +}; |
| 42 | + |
| 43 | +static unsigned int heartbeat; |
| 44 | +static bool nowayout = WATCHDOG_NOWAYOUT; |
| 45 | + |
| 46 | +static int bcm2835_wdt_start(struct watchdog_device *wdog) |
| 47 | +{ |
| 48 | + struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); |
| 49 | + uint32_t cur; |
| 50 | + unsigned long flags; |
| 51 | + |
| 52 | + spin_lock_irqsave(&wdt->lock, flags); |
| 53 | + |
| 54 | + writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) & |
| 55 | + PM_WDOG_TIME_SET), wdt->base + PM_WDOG); |
| 56 | + cur = readl_relaxed(wdt->base + PM_RSTC); |
| 57 | + writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | |
| 58 | + PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC); |
| 59 | + |
| 60 | + spin_unlock_irqrestore(&wdt->lock, flags); |
| 61 | + |
| 62 | + return 0; |
| 63 | +} |
| 64 | + |
| 65 | +static int bcm2835_wdt_stop(struct watchdog_device *wdog) |
| 66 | +{ |
| 67 | + struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); |
| 68 | + |
| 69 | + writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC); |
| 70 | + dev_info(wdog->dev, "Watchdog timer stopped"); |
| 71 | + return 0; |
| 72 | +} |
| 73 | + |
| 74 | +static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) |
| 75 | +{ |
| 76 | + wdog->timeout = t; |
| 77 | + return 0; |
| 78 | +} |
| 79 | + |
| 80 | +static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog) |
| 81 | +{ |
| 82 | + struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); |
| 83 | + |
| 84 | + uint32_t ret = readl_relaxed(wdt->base + PM_WDOG); |
| 85 | + return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET); |
| 86 | +} |
| 87 | + |
| 88 | +static struct watchdog_ops bcm2835_wdt_ops = { |
| 89 | + .owner = THIS_MODULE, |
| 90 | + .start = bcm2835_wdt_start, |
| 91 | + .stop = bcm2835_wdt_stop, |
| 92 | + .set_timeout = bcm2835_wdt_set_timeout, |
| 93 | + .get_timeleft = bcm2835_wdt_get_timeleft, |
| 94 | +}; |
| 95 | + |
| 96 | +static struct watchdog_info bcm2835_wdt_info = { |
| 97 | + .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | |
| 98 | + WDIOF_KEEPALIVEPING, |
| 99 | + .identity = "Broadcom BCM2835 Watchdog timer", |
| 100 | +}; |
| 101 | + |
| 102 | +static struct watchdog_device bcm2835_wdt_wdd = { |
| 103 | + .info = &bcm2835_wdt_info, |
| 104 | + .ops = &bcm2835_wdt_ops, |
| 105 | + .min_timeout = 1, |
| 106 | + .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), |
| 107 | + .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), |
| 108 | +}; |
| 109 | + |
| 110 | +static int bcm2835_wdt_probe(struct platform_device *pdev) |
| 111 | +{ |
| 112 | + struct device *dev = &pdev->dev; |
| 113 | + struct device_node *np = dev->of_node; |
| 114 | + struct bcm2835_wdt *wdt; |
| 115 | + int err; |
| 116 | + |
| 117 | + wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL); |
| 118 | + if (!wdt) { |
| 119 | + dev_err(dev, "Failed to allocate memory for watchdog device"); |
| 120 | + return -ENOMEM; |
| 121 | + } |
| 122 | + platform_set_drvdata(pdev, wdt); |
| 123 | + |
| 124 | + spin_lock_init(&wdt->lock); |
| 125 | + |
| 126 | + wdt->base = of_iomap(np, 0); |
| 127 | + if (!wdt->base) { |
| 128 | + dev_err(dev, "Failed to remap watchdog regs"); |
| 129 | + return -ENODEV; |
| 130 | + } |
| 131 | + |
| 132 | + watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt); |
| 133 | + watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev); |
| 134 | + watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout); |
| 135 | + err = watchdog_register_device(&bcm2835_wdt_wdd); |
| 136 | + if (err) { |
| 137 | + dev_err(dev, "Failed to register watchdog device"); |
| 138 | + iounmap(wdt->base); |
| 139 | + return err; |
| 140 | + } |
| 141 | + |
| 142 | + dev_info(dev, "Broadcom BCM2835 watchdog timer"); |
| 143 | + return 0; |
| 144 | +} |
| 145 | + |
| 146 | +static int bcm2835_wdt_remove(struct platform_device *pdev) |
| 147 | +{ |
| 148 | + struct bcm2835_wdt *wdt = platform_get_drvdata(pdev); |
| 149 | + |
| 150 | + watchdog_unregister_device(&bcm2835_wdt_wdd); |
| 151 | + iounmap(wdt->base); |
| 152 | + |
| 153 | + return 0; |
| 154 | +} |
| 155 | + |
| 156 | +static void bcm2835_wdt_shutdown(struct platform_device *pdev) |
| 157 | +{ |
| 158 | + bcm2835_wdt_stop(&bcm2835_wdt_wdd); |
| 159 | +} |
| 160 | + |
| 161 | +static const struct of_device_id bcm2835_wdt_of_match[] = { |
| 162 | + { .compatible = "brcm,bcm2835-pm-wdt", }, |
| 163 | + {}, |
| 164 | +}; |
| 165 | +MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match); |
| 166 | + |
| 167 | +static struct platform_driver bcm2835_wdt_driver = { |
| 168 | + .probe = bcm2835_wdt_probe, |
| 169 | + .remove = bcm2835_wdt_remove, |
| 170 | + .shutdown = bcm2835_wdt_shutdown, |
| 171 | + .driver = { |
| 172 | + .name = "bcm2835-wdt", |
| 173 | + .owner = THIS_MODULE, |
| 174 | + .of_match_table = bcm2835_wdt_of_match, |
| 175 | + }, |
| 176 | +}; |
| 177 | +module_platform_driver(bcm2835_wdt_driver); |
| 178 | + |
| 179 | +module_param(heartbeat, uint, 0); |
| 180 | +MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds"); |
| 181 | + |
| 182 | +module_param(nowayout, bool, 0); |
| 183 | +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
| 184 | + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 185 | + |
| 186 | +MODULE_AUTHOR( "Lubomir Rintel <[email protected]>"); |
| 187 | +MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer"); |
| 188 | +MODULE_LICENSE("GPL"); |
| 189 | +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
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