1 /* 2 * intel-mid_wdt: generic Intel MID SCU watchdog driver 3 * 4 * Platforms supported so far: 5 * - Merrifield only 6 * 7 * Copyright (C) 2014 Intel Corporation. All rights reserved. 8 * Contact: David Cohen <david.a.cohen@linux.intel.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of version 2 of the GNU General 12 * Public License as published by the Free Software Foundation. 13 */ 14 15 #include <linux/interrupt.h> 16 #include <linux/module.h> 17 #include <linux/nmi.h> 18 #include <linux/platform_device.h> 19 #include <linux/watchdog.h> 20 #include <linux/platform_data/intel-mid_wdt.h> 21 22 #include <asm/intel_scu_ipc.h> 23 #include <asm/intel-mid.h> 24 25 #define IPC_WATCHDOG 0xf8 26 27 #define MID_WDT_PRETIMEOUT 15 28 #define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT) 29 #define MID_WDT_TIMEOUT_MAX 170 30 #define MID_WDT_DEFAULT_TIMEOUT 90 31 32 /* SCU watchdog messages */ 33 enum { 34 SCU_WATCHDOG_START = 0, 35 SCU_WATCHDOG_STOP, 36 SCU_WATCHDOG_KEEPALIVE, 37 }; 38 39 static inline int wdt_command(int sub, u32 *in, int inlen) 40 { 41 return intel_scu_ipc_command(IPC_WATCHDOG, sub, in, inlen, NULL, 0); 42 } 43 44 static int wdt_start(struct watchdog_device *wd) 45 { 46 int ret, in_size; 47 int timeout = wd->timeout; 48 struct ipc_wd_start { 49 u32 pretimeout; 50 u32 timeout; 51 } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout }; 52 53 /* 54 * SCU expects the input size for watchdog IPC to 55 * be based on 4 bytes 56 */ 57 in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4); 58 59 ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size); 60 if (ret) { 61 struct device *dev = watchdog_get_drvdata(wd); 62 dev_crit(dev, "error starting watchdog: %d\n", ret); 63 } 64 65 return ret; 66 } 67 68 static int wdt_ping(struct watchdog_device *wd) 69 { 70 int ret; 71 72 ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0); 73 if (ret) { 74 struct device *dev = watchdog_get_drvdata(wd); 75 dev_crit(dev, "Error executing keepalive: 0x%x\n", ret); 76 } 77 78 return ret; 79 } 80 81 static int wdt_stop(struct watchdog_device *wd) 82 { 83 int ret; 84 85 ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0); 86 if (ret) { 87 struct device *dev = watchdog_get_drvdata(wd); 88 dev_crit(dev, "Error stopping watchdog: 0x%x\n", ret); 89 } 90 91 return ret; 92 } 93 94 static irqreturn_t mid_wdt_irq(int irq, void *dev_id) 95 { 96 panic("Kernel Watchdog"); 97 98 /* This code should not be reached */ 99 return IRQ_HANDLED; 100 } 101 102 static const struct watchdog_info mid_wdt_info = { 103 .identity = "Intel MID SCU watchdog", 104 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, 105 }; 106 107 static const struct watchdog_ops mid_wdt_ops = { 108 .owner = THIS_MODULE, 109 .start = wdt_start, 110 .stop = wdt_stop, 111 .ping = wdt_ping, 112 }; 113 114 static int mid_wdt_probe(struct platform_device *pdev) 115 { 116 struct watchdog_device *wdt_dev; 117 struct intel_mid_wdt_pdata *pdata = pdev->dev.platform_data; 118 int ret; 119 120 if (!pdata) { 121 dev_err(&pdev->dev, "missing platform data\n"); 122 return -EINVAL; 123 } 124 125 if (pdata->probe) { 126 ret = pdata->probe(pdev); 127 if (ret) 128 return ret; 129 } 130 131 wdt_dev = devm_kzalloc(&pdev->dev, sizeof(*wdt_dev), GFP_KERNEL); 132 if (!wdt_dev) 133 return -ENOMEM; 134 135 wdt_dev->info = &mid_wdt_info; 136 wdt_dev->ops = &mid_wdt_ops; 137 wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN; 138 wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX; 139 wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT; 140 141 watchdog_set_drvdata(wdt_dev, &pdev->dev); 142 platform_set_drvdata(pdev, wdt_dev); 143 144 ret = devm_request_irq(&pdev->dev, pdata->irq, mid_wdt_irq, 145 IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog", 146 wdt_dev); 147 if (ret) { 148 dev_err(&pdev->dev, "error requesting warning irq %d\n", 149 pdata->irq); 150 return ret; 151 } 152 153 ret = watchdog_register_device(wdt_dev); 154 if (ret) { 155 dev_err(&pdev->dev, "error registering watchdog device\n"); 156 return ret; 157 } 158 159 dev_info(&pdev->dev, "Intel MID watchdog device probed\n"); 160 161 return 0; 162 } 163 164 static int mid_wdt_remove(struct platform_device *pdev) 165 { 166 struct watchdog_device *wd = platform_get_drvdata(pdev); 167 watchdog_unregister_device(wd); 168 return 0; 169 } 170 171 static struct platform_driver mid_wdt_driver = { 172 .probe = mid_wdt_probe, 173 .remove = mid_wdt_remove, 174 .driver = { 175 .owner = THIS_MODULE, 176 .name = "intel_mid_wdt", 177 }, 178 }; 179 180 module_platform_driver(mid_wdt_driver); 181 182 MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>"); 183 MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform"); 184 MODULE_LICENSE("GPL"); 185