1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface 4 * 5 * Authors: Dave Updegraff <dave@cray.org> 6 * Kumar Gala <galak@kernel.crashing.org> 7 * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org> 8 * ..and from sc520_wdt 9 * Copyright (c) 2008 MontaVista Software, Inc. 10 * Anton Vorontsov <avorontsov@ru.mvista.com> 11 * 12 * Note: it appears that you can only actually ENABLE or DISABLE the thing 13 * once after POR. Once enabled, you cannot disable, and vice versa. 14 */ 15 16 #include <linux/fs.h> 17 #include <linux/init.h> 18 #include <linux/kernel.h> 19 #include <linux/of_address.h> 20 #include <linux/of_platform.h> 21 #include <linux/module.h> 22 #include <linux/watchdog.h> 23 #include <linux/io.h> 24 #include <linux/uaccess.h> 25 #include <sysdev/fsl_soc.h> 26 27 #define WATCHDOG_TIMEOUT 10 28 29 struct mpc8xxx_wdt { 30 __be32 res0; 31 __be32 swcrr; /* System watchdog control register */ 32 #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */ 33 #define SWCRR_SWF 0x00000008 /* Software Watchdog Freeze (mpc8xx). */ 34 #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */ 35 #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/ 36 #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */ 37 __be32 swcnr; /* System watchdog count register */ 38 u8 res1[2]; 39 __be16 swsrr; /* System watchdog service register */ 40 u8 res2[0xF0]; 41 }; 42 43 struct mpc8xxx_wdt_type { 44 int prescaler; 45 bool hw_enabled; 46 u32 rsr_mask; 47 }; 48 49 struct mpc8xxx_wdt_ddata { 50 struct mpc8xxx_wdt __iomem *base; 51 struct watchdog_device wdd; 52 spinlock_t lock; 53 u16 swtc; 54 }; 55 56 static u16 timeout; 57 module_param(timeout, ushort, 0); 58 MODULE_PARM_DESC(timeout, 59 "Watchdog timeout in seconds. (1<timeout<65535, default=" 60 __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 61 62 static bool reset = 1; 63 module_param(reset, bool, 0); 64 MODULE_PARM_DESC(reset, 65 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset"); 66 67 static bool nowayout = WATCHDOG_NOWAYOUT; 68 module_param(nowayout, bool, 0); 69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 70 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 71 72 static void mpc8xxx_wdt_keepalive(struct mpc8xxx_wdt_ddata *ddata) 73 { 74 /* Ping the WDT */ 75 spin_lock(&ddata->lock); 76 out_be16(&ddata->base->swsrr, 0x556c); 77 out_be16(&ddata->base->swsrr, 0xaa39); 78 spin_unlock(&ddata->lock); 79 } 80 81 static int mpc8xxx_wdt_start(struct watchdog_device *w) 82 { 83 struct mpc8xxx_wdt_ddata *ddata = 84 container_of(w, struct mpc8xxx_wdt_ddata, wdd); 85 u32 tmp = in_be32(&ddata->base->swcrr); 86 87 /* Good, fire up the show */ 88 tmp &= ~(SWCRR_SWTC | SWCRR_SWF | SWCRR_SWEN | SWCRR_SWRI | SWCRR_SWPR); 89 tmp |= SWCRR_SWEN | SWCRR_SWPR | (ddata->swtc << 16); 90 91 if (reset) 92 tmp |= SWCRR_SWRI; 93 94 out_be32(&ddata->base->swcrr, tmp); 95 96 tmp = in_be32(&ddata->base->swcrr); 97 if (!(tmp & SWCRR_SWEN)) 98 return -EOPNOTSUPP; 99 100 ddata->swtc = tmp >> 16; 101 set_bit(WDOG_HW_RUNNING, &ddata->wdd.status); 102 103 return 0; 104 } 105 106 static int mpc8xxx_wdt_ping(struct watchdog_device *w) 107 { 108 struct mpc8xxx_wdt_ddata *ddata = 109 container_of(w, struct mpc8xxx_wdt_ddata, wdd); 110 111 mpc8xxx_wdt_keepalive(ddata); 112 return 0; 113 } 114 115 static struct watchdog_info mpc8xxx_wdt_info = { 116 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, 117 .firmware_version = 1, 118 .identity = "MPC8xxx", 119 }; 120 121 static struct watchdog_ops mpc8xxx_wdt_ops = { 122 .owner = THIS_MODULE, 123 .start = mpc8xxx_wdt_start, 124 .ping = mpc8xxx_wdt_ping, 125 }; 126 127 static int mpc8xxx_wdt_probe(struct platform_device *ofdev) 128 { 129 int ret; 130 struct resource *res; 131 const struct mpc8xxx_wdt_type *wdt_type; 132 struct mpc8xxx_wdt_ddata *ddata; 133 u32 freq = fsl_get_sys_freq(); 134 bool enabled; 135 struct device *dev = &ofdev->dev; 136 137 wdt_type = of_device_get_match_data(dev); 138 if (!wdt_type) 139 return -EINVAL; 140 141 if (!freq || freq == -1) 142 return -EINVAL; 143 144 ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); 145 if (!ddata) 146 return -ENOMEM; 147 148 ddata->base = devm_platform_ioremap_resource(ofdev, 0); 149 if (IS_ERR(ddata->base)) 150 return PTR_ERR(ddata->base); 151 152 enabled = in_be32(&ddata->base->swcrr) & SWCRR_SWEN; 153 if (!enabled && wdt_type->hw_enabled) { 154 dev_info(dev, "could not be enabled in software\n"); 155 return -ENODEV; 156 } 157 158 res = platform_get_resource(ofdev, IORESOURCE_MEM, 1); 159 if (res) { 160 bool status; 161 u32 __iomem *rsr = ioremap(res->start, resource_size(res)); 162 163 if (!rsr) 164 return -ENOMEM; 165 166 status = in_be32(rsr) & wdt_type->rsr_mask; 167 ddata->wdd.bootstatus = status ? WDIOF_CARDRESET : 0; 168 /* clear reset status bits related to watchdog timer */ 169 out_be32(rsr, wdt_type->rsr_mask); 170 iounmap(rsr); 171 172 dev_info(dev, "Last boot was %scaused by watchdog\n", 173 status ? "" : "not "); 174 } 175 176 spin_lock_init(&ddata->lock); 177 178 ddata->wdd.info = &mpc8xxx_wdt_info; 179 ddata->wdd.ops = &mpc8xxx_wdt_ops; 180 181 ddata->wdd.timeout = WATCHDOG_TIMEOUT; 182 watchdog_init_timeout(&ddata->wdd, timeout, dev); 183 184 watchdog_set_nowayout(&ddata->wdd, nowayout); 185 186 ddata->swtc = min(ddata->wdd.timeout * freq / wdt_type->prescaler, 187 0xffffU); 188 189 /* 190 * If the watchdog was previously enabled or we're running on 191 * MPC8xxx, we should ping the wdt from the kernel until the 192 * userspace handles it. 193 */ 194 if (enabled) 195 mpc8xxx_wdt_start(&ddata->wdd); 196 197 ddata->wdd.max_hw_heartbeat_ms = (ddata->swtc * wdt_type->prescaler) / 198 (freq / 1000); 199 ddata->wdd.min_timeout = ddata->wdd.max_hw_heartbeat_ms / 1000; 200 if (ddata->wdd.timeout < ddata->wdd.min_timeout) 201 ddata->wdd.timeout = ddata->wdd.min_timeout; 202 203 ret = devm_watchdog_register_device(dev, &ddata->wdd); 204 if (ret) 205 return ret; 206 207 dev_info(dev, 208 "WDT driver for MPC8xxx initialized. mode:%s timeout=%d sec\n", 209 reset ? "reset" : "interrupt", ddata->wdd.timeout); 210 211 platform_set_drvdata(ofdev, ddata); 212 return 0; 213 } 214 215 static const struct of_device_id mpc8xxx_wdt_match[] = { 216 { 217 .compatible = "mpc83xx_wdt", 218 .data = &(struct mpc8xxx_wdt_type) { 219 .prescaler = 0x10000, 220 .rsr_mask = BIT(3), /* RSR Bit SWRS */ 221 }, 222 }, 223 { 224 .compatible = "fsl,mpc8610-wdt", 225 .data = &(struct mpc8xxx_wdt_type) { 226 .prescaler = 0x10000, 227 .hw_enabled = true, 228 .rsr_mask = BIT(20), /* RSTRSCR Bit WDT_RR */ 229 }, 230 }, 231 { 232 .compatible = "fsl,mpc823-wdt", 233 .data = &(struct mpc8xxx_wdt_type) { 234 .prescaler = 0x800, 235 .hw_enabled = true, 236 .rsr_mask = BIT(28), /* RSR Bit SWRS */ 237 }, 238 }, 239 {}, 240 }; 241 MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match); 242 243 static struct platform_driver mpc8xxx_wdt_driver = { 244 .probe = mpc8xxx_wdt_probe, 245 .driver = { 246 .name = "mpc8xxx_wdt", 247 .of_match_table = mpc8xxx_wdt_match, 248 }, 249 }; 250 251 static int __init mpc8xxx_wdt_init(void) 252 { 253 return platform_driver_register(&mpc8xxx_wdt_driver); 254 } 255 arch_initcall(mpc8xxx_wdt_init); 256 257 static void __exit mpc8xxx_wdt_exit(void) 258 { 259 platform_driver_unregister(&mpc8xxx_wdt_driver); 260 } 261 module_exit(mpc8xxx_wdt_exit); 262 263 MODULE_AUTHOR("Dave Updegraff, Kumar Gala"); 264 MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx " 265 "uProcessors"); 266 MODULE_LICENSE("GPL"); 267