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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 | // SPDX-License-Identifier: GPL-2.0-only /* * intel-mid_wdt: generic Intel MID SCU watchdog driver * * Platforms supported so far: * - Merrifield only * * Copyright (C) 2014 Intel Corporation. All rights reserved. * Contact: David Cohen <david.a.cohen@linux.intel.com> */ #include <linux/interrupt.h> #include <linux/module.h> #include <linux/nmi.h> #include <linux/platform_device.h> #include <linux/watchdog.h> #include <linux/platform_data/intel-mid_wdt.h> #include <asm/intel_scu_ipc.h> #include <asm/intel-mid.h> #define IPC_WATCHDOG 0xf8 #define MID_WDT_PRETIMEOUT 15 #define MID_WDT_TIMEOUT_MIN (1 + MID_WDT_PRETIMEOUT) #define MID_WDT_TIMEOUT_MAX 170 #define MID_WDT_DEFAULT_TIMEOUT 90 /* SCU watchdog messages */ enum { SCU_WATCHDOG_START = 0, SCU_WATCHDOG_STOP, SCU_WATCHDOG_KEEPALIVE, }; static inline int wdt_command(int sub, u32 *in, int inlen) { return intel_scu_ipc_command(IPC_WATCHDOG, sub, in, inlen, NULL, 0); } static int wdt_start(struct watchdog_device *wd) { struct device *dev = watchdog_get_drvdata(wd); int ret, in_size; int timeout = wd->timeout; struct ipc_wd_start { u32 pretimeout; u32 timeout; } ipc_wd_start = { timeout - MID_WDT_PRETIMEOUT, timeout }; /* * SCU expects the input size for watchdog IPC to * be based on 4 bytes */ in_size = DIV_ROUND_UP(sizeof(ipc_wd_start), 4); ret = wdt_command(SCU_WATCHDOG_START, (u32 *)&ipc_wd_start, in_size); if (ret) dev_crit(dev, "error starting watchdog: %d\n", ret); return ret; } static int wdt_ping(struct watchdog_device *wd) { struct device *dev = watchdog_get_drvdata(wd); int ret; ret = wdt_command(SCU_WATCHDOG_KEEPALIVE, NULL, 0); if (ret) dev_crit(dev, "Error executing keepalive: %d\n", ret); return ret; } static int wdt_stop(struct watchdog_device *wd) { struct device *dev = watchdog_get_drvdata(wd); int ret; ret = wdt_command(SCU_WATCHDOG_STOP, NULL, 0); if (ret) dev_crit(dev, "Error stopping watchdog: %d\n", ret); return ret; } static irqreturn_t mid_wdt_irq(int irq, void *dev_id) { panic("Kernel Watchdog"); /* This code should not be reached */ return IRQ_HANDLED; } static const struct watchdog_info mid_wdt_info = { .identity = "Intel MID SCU watchdog", .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE, }; static const struct watchdog_ops mid_wdt_ops = { .owner = THIS_MODULE, .start = wdt_start, .stop = wdt_stop, .ping = wdt_ping, }; static int mid_wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct watchdog_device *wdt_dev; struct intel_mid_wdt_pdata *pdata = dev->platform_data; int ret; if (!pdata) { dev_err(dev, "missing platform data\n"); return -EINVAL; } if (pdata->probe) { ret = pdata->probe(pdev); if (ret) return ret; } wdt_dev = devm_kzalloc(dev, sizeof(*wdt_dev), GFP_KERNEL); if (!wdt_dev) return -ENOMEM; wdt_dev->info = &mid_wdt_info; wdt_dev->ops = &mid_wdt_ops; wdt_dev->min_timeout = MID_WDT_TIMEOUT_MIN; wdt_dev->max_timeout = MID_WDT_TIMEOUT_MAX; wdt_dev->timeout = MID_WDT_DEFAULT_TIMEOUT; wdt_dev->parent = dev; watchdog_set_nowayout(wdt_dev, WATCHDOG_NOWAYOUT); watchdog_set_drvdata(wdt_dev, dev); ret = devm_request_irq(dev, pdata->irq, mid_wdt_irq, IRQF_SHARED | IRQF_NO_SUSPEND, "watchdog", wdt_dev); if (ret) { dev_err(dev, "error requesting warning irq %d\n", pdata->irq); return ret; } /* * The firmware followed by U-Boot leaves the watchdog running * with the default threshold which may vary. When we get here * we should make a decision to prevent any side effects before * user space daemon will take care of it. The best option, * taking into consideration that there is no way to read values * back from hardware, is to enforce watchdog being run with * deterministic values. */ ret = wdt_start(wdt_dev); if (ret) return ret; /* Make sure the watchdog is serviced */ set_bit(WDOG_HW_RUNNING, &wdt_dev->status); ret = devm_watchdog_register_device(dev, wdt_dev); if (ret) return ret; dev_info(dev, "Intel MID watchdog device probed\n"); return 0; } static struct platform_driver mid_wdt_driver = { .probe = mid_wdt_probe, .driver = { .name = "intel_mid_wdt", }, }; module_platform_driver(mid_wdt_driver); MODULE_AUTHOR("David Cohen <david.a.cohen@linux.intel.com>"); MODULE_DESCRIPTION("Watchdog Driver for Intel MID platform"); MODULE_LICENSE("GPL"); |