| 1 | /* |
| 2 | * Watchdog driver for Cirrus Logic EP93xx family of devices. |
| 3 | * |
| 4 | * Copyright (c) 2004 Ray Lehtiniemi |
| 5 | * Copyright (c) 2006 Tower Technologies |
| 6 | * Based on ep93xx driver, bits from alim7101_wdt.c |
| 7 | * |
| 8 | * Authors: Ray Lehtiniemi <rayl@mail.com>, |
| 9 | * Alessandro Zummo <a.zummo@towertech.it> |
| 10 | * |
| 11 | * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com> |
| 12 | * Convert to a platform device and use the watchdog framework API |
| 13 | * |
| 14 | * This file is licensed under the terms of the GNU General Public |
| 15 | * License version 2. This program is licensed "as is" without any |
| 16 | * warranty of any kind, whether express or implied. |
| 17 | * |
| 18 | * This watchdog fires after 250msec, which is a too short interval |
| 19 | * for us to rely on the user space daemon alone. So we ping the |
| 20 | * wdt each ~200msec and eventually stop doing it if the user space |
| 21 | * daemon dies. |
| 22 | * |
| 23 | * TODO: |
| 24 | * |
| 25 | * - Test last reset from watchdog status |
| 26 | * - Add a few missing ioctls |
| 27 | */ |
| 28 | |
| 29 | #include <linux/platform_device.h> |
| 30 | #include <linux/module.h> |
| 31 | #include <linux/watchdog.h> |
| 32 | #include <linux/timer.h> |
| 33 | #include <linux/io.h> |
| 34 | |
| 35 | #define WDT_VERSION "0.4" |
| 36 | |
| 37 | /* default timeout (secs) */ |
| 38 | #define WDT_TIMEOUT 30 |
| 39 | |
| 40 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 41 | module_param(nowayout, bool, 0); |
| 42 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
| 43 | |
| 44 | static unsigned int timeout = WDT_TIMEOUT; |
| 45 | module_param(timeout, uint, 0); |
| 46 | MODULE_PARM_DESC(timeout, |
| 47 | "Watchdog timeout in seconds. (1<=timeout<=3600, default=" |
| 48 | __MODULE_STRING(WDT_TIMEOUT) ")"); |
| 49 | |
| 50 | static void __iomem *mmio_base; |
| 51 | static struct timer_list timer; |
| 52 | static unsigned long next_heartbeat; |
| 53 | |
| 54 | #define EP93XX_WATCHDOG 0x00 |
| 55 | #define EP93XX_WDSTATUS 0x04 |
| 56 | |
| 57 | /* reset the wdt every ~200ms - the heartbeat of the device is 0.250 seconds*/ |
| 58 | #define WDT_INTERVAL (HZ/5) |
| 59 | |
| 60 | static void ep93xx_wdt_timer_ping(unsigned long data) |
| 61 | { |
| 62 | if (time_before(jiffies, next_heartbeat)) |
| 63 | writel(0x5555, mmio_base + EP93XX_WATCHDOG); |
| 64 | |
| 65 | /* Re-set the timer interval */ |
| 66 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
| 67 | } |
| 68 | |
| 69 | static int ep93xx_wdt_start(struct watchdog_device *wdd) |
| 70 | { |
| 71 | next_heartbeat = jiffies + (timeout * HZ); |
| 72 | |
| 73 | writel(0xaaaa, mmio_base + EP93XX_WATCHDOG); |
| 74 | mod_timer(&timer, jiffies + WDT_INTERVAL); |
| 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | static int ep93xx_wdt_stop(struct watchdog_device *wdd) |
| 80 | { |
| 81 | del_timer_sync(&timer); |
| 82 | writel(0xaa55, mmio_base + EP93XX_WATCHDOG); |
| 83 | |
| 84 | return 0; |
| 85 | } |
| 86 | |
| 87 | static int ep93xx_wdt_keepalive(struct watchdog_device *wdd) |
| 88 | { |
| 89 | /* user land ping */ |
| 90 | next_heartbeat = jiffies + (timeout * HZ); |
| 91 | |
| 92 | return 0; |
| 93 | } |
| 94 | |
| 95 | static const struct watchdog_info ep93xx_wdt_ident = { |
| 96 | .options = WDIOF_CARDRESET | |
| 97 | WDIOF_MAGICCLOSE | |
| 98 | WDIOF_KEEPALIVEPING, |
| 99 | .identity = "EP93xx Watchdog", |
| 100 | }; |
| 101 | |
| 102 | static struct watchdog_ops ep93xx_wdt_ops = { |
| 103 | .owner = THIS_MODULE, |
| 104 | .start = ep93xx_wdt_start, |
| 105 | .stop = ep93xx_wdt_stop, |
| 106 | .ping = ep93xx_wdt_keepalive, |
| 107 | }; |
| 108 | |
| 109 | static struct watchdog_device ep93xx_wdt_wdd = { |
| 110 | .info = &ep93xx_wdt_ident, |
| 111 | .ops = &ep93xx_wdt_ops, |
| 112 | }; |
| 113 | |
| 114 | static int ep93xx_wdt_probe(struct platform_device *pdev) |
| 115 | { |
| 116 | struct resource *res; |
| 117 | unsigned long val; |
| 118 | int err; |
| 119 | |
| 120 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 121 | mmio_base = devm_ioremap_resource(&pdev->dev, res); |
| 122 | if (IS_ERR(mmio_base)) |
| 123 | return PTR_ERR(mmio_base); |
| 124 | |
| 125 | if (timeout < 1 || timeout > 3600) { |
| 126 | timeout = WDT_TIMEOUT; |
| 127 | dev_warn(&pdev->dev, |
| 128 | "timeout value must be 1<=x<=3600, using %d\n", |
| 129 | timeout); |
| 130 | } |
| 131 | |
| 132 | val = readl(mmio_base + EP93XX_WATCHDOG); |
| 133 | ep93xx_wdt_wdd.bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0; |
| 134 | ep93xx_wdt_wdd.timeout = timeout; |
| 135 | |
| 136 | watchdog_set_nowayout(&ep93xx_wdt_wdd, nowayout); |
| 137 | |
| 138 | setup_timer(&timer, ep93xx_wdt_timer_ping, 1); |
| 139 | |
| 140 | err = watchdog_register_device(&ep93xx_wdt_wdd); |
| 141 | if (err) |
| 142 | return err; |
| 143 | |
| 144 | dev_info(&pdev->dev, |
| 145 | "EP93XX watchdog, driver version " WDT_VERSION "%s\n", |
| 146 | (val & 0x08) ? " (nCS1 disable detected)" : ""); |
| 147 | |
| 148 | return 0; |
| 149 | } |
| 150 | |
| 151 | static int ep93xx_wdt_remove(struct platform_device *pdev) |
| 152 | { |
| 153 | watchdog_unregister_device(&ep93xx_wdt_wdd); |
| 154 | return 0; |
| 155 | } |
| 156 | |
| 157 | static struct platform_driver ep93xx_wdt_driver = { |
| 158 | .driver = { |
| 159 | .name = "ep93xx-wdt", |
| 160 | }, |
| 161 | .probe = ep93xx_wdt_probe, |
| 162 | .remove = ep93xx_wdt_remove, |
| 163 | }; |
| 164 | |
| 165 | module_platform_driver(ep93xx_wdt_driver); |
| 166 | |
| 167 | MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>"); |
| 168 | MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); |
| 169 | MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); |
| 170 | MODULE_DESCRIPTION("EP93xx Watchdog"); |
| 171 | MODULE_LICENSE("GPL"); |
| 172 | MODULE_VERSION(WDT_VERSION); |