1 /* 2 * MPC5200 General Purpose Timer device driver 3 * 4 * Copyright (c) 2009 Secret Lab Technologies Ltd. 5 * Copyright (c) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix 6 * 7 * This program is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by the 9 * Free Software Foundation; either version 2 of the License, or (at your 10 * option) any later version. 11 * 12 * This file is a driver for the the General Purpose Timer (gpt) devices 13 * found on the MPC5200 SoC. Each timer has an IO pin which can be used 14 * for GPIO or can be used to raise interrupts. The timer function can 15 * be used independently from the IO pin, or it can be used to control 16 * output signals or measure input signals. 17 * 18 * This driver supports the GPIO and IRQ controller functions of the GPT 19 * device. Timer functions are not yet supported. 20 * 21 * The timer gpt0 can be used as watchdog (wdt). If the wdt mode is used, 22 * this prevents the use of any gpt0 gpt function (i.e. they will fail with 23 * -EBUSY). Thus, the safety wdt function always has precedence over the gpt 24 * function. If the kernel has been compiled with CONFIG_WATCHDOG_NOWAYOUT, 25 * this means that gpt0 is locked in wdt mode until the next reboot - this 26 * may be a requirement in safety applications. 27 * 28 * To use the GPIO function, the following two properties must be added 29 * to the device tree node for the gpt device (typically in the .dts file 30 * for the board): 31 * gpio-controller; 32 * #gpio-cells = < 2 >; 33 * This driver will register the GPIO pin if it finds the gpio-controller 34 * property in the device tree. 35 * 36 * To use the IRQ controller function, the following two properties must 37 * be added to the device tree node for the gpt device: 38 * interrupt-controller; 39 * #interrupt-cells = < 1 >; 40 * The IRQ controller binding only uses one cell to specify the interrupt, 41 * and the IRQ flags are encoded in the cell. A cell is not used to encode 42 * the IRQ number because the GPT only has a single IRQ source. For flags, 43 * a value of '1' means rising edge sensitive and '2' means falling edge. 44 * 45 * The GPIO and the IRQ controller functions can be used at the same time, 46 * but in this use case the IO line will only work as an input. Trying to 47 * use it as a GPIO output will not work. 48 * 49 * When using the GPIO line as an output, it can either be driven as normal 50 * IO, or it can be an Open Collector (OC) output. At the moment it is the 51 * responsibility of either the bootloader or the platform setup code to set 52 * the output mode. This driver does not change the output mode setting. 53 */ 54 55 #include <linux/device.h> 56 #include <linux/irq.h> 57 #include <linux/interrupt.h> 58 #include <linux/io.h> 59 #include <linux/list.h> 60 #include <linux/mutex.h> 61 #include <linux/of.h> 62 #include <linux/of_platform.h> 63 #include <linux/of_gpio.h> 64 #include <linux/kernel.h> 65 #include <linux/slab.h> 66 #include <linux/fs.h> 67 #include <linux/watchdog.h> 68 #include <linux/miscdevice.h> 69 #include <linux/uaccess.h> 70 #include <linux/module.h> 71 #include <asm/div64.h> 72 #include <asm/mpc52xx.h> 73 74 MODULE_DESCRIPTION("Freescale MPC52xx gpt driver"); 75 MODULE_AUTHOR("Sascha Hauer, Grant Likely, Albrecht Dreß"); 76 MODULE_LICENSE("GPL"); 77 78 /** 79 * struct mpc52xx_gpt - Private data structure for MPC52xx GPT driver 80 * @dev: pointer to device structure 81 * @regs: virtual address of GPT registers 82 * @lock: spinlock to coordinate between different functions. 83 * @gc: gpio_chip instance structure; used when GPIO is enabled 84 * @irqhost: Pointer to irq_domain instance; used when IRQ mode is supported 85 * @wdt_mode: only relevant for gpt0: bit 0 (MPC52xx_GPT_CAN_WDT) indicates 86 * if the gpt may be used as wdt, bit 1 (MPC52xx_GPT_IS_WDT) indicates 87 * if the timer is actively used as wdt which blocks gpt functions 88 */ 89 struct mpc52xx_gpt_priv { 90 struct list_head list; /* List of all GPT devices */ 91 struct device *dev; 92 struct mpc52xx_gpt __iomem *regs; 93 raw_spinlock_t lock; 94 struct irq_domain *irqhost; 95 u32 ipb_freq; 96 u8 wdt_mode; 97 98 #if defined(CONFIG_GPIOLIB) 99 struct gpio_chip gc; 100 #endif 101 }; 102 103 LIST_HEAD(mpc52xx_gpt_list); 104 DEFINE_MUTEX(mpc52xx_gpt_list_mutex); 105 106 #define MPC52xx_GPT_MODE_MS_MASK (0x07) 107 #define MPC52xx_GPT_MODE_MS_IC (0x01) 108 #define MPC52xx_GPT_MODE_MS_OC (0x02) 109 #define MPC52xx_GPT_MODE_MS_PWM (0x03) 110 #define MPC52xx_GPT_MODE_MS_GPIO (0x04) 111 112 #define MPC52xx_GPT_MODE_GPIO_MASK (0x30) 113 #define MPC52xx_GPT_MODE_GPIO_OUT_LOW (0x20) 114 #define MPC52xx_GPT_MODE_GPIO_OUT_HIGH (0x30) 115 116 #define MPC52xx_GPT_MODE_COUNTER_ENABLE (0x1000) 117 #define MPC52xx_GPT_MODE_CONTINUOUS (0x0400) 118 #define MPC52xx_GPT_MODE_OPEN_DRAIN (0x0200) 119 #define MPC52xx_GPT_MODE_IRQ_EN (0x0100) 120 #define MPC52xx_GPT_MODE_WDT_EN (0x8000) 121 122 #define MPC52xx_GPT_MODE_ICT_MASK (0x030000) 123 #define MPC52xx_GPT_MODE_ICT_RISING (0x010000) 124 #define MPC52xx_GPT_MODE_ICT_FALLING (0x020000) 125 #define MPC52xx_GPT_MODE_ICT_TOGGLE (0x030000) 126 127 #define MPC52xx_GPT_MODE_WDT_PING (0xa5) 128 129 #define MPC52xx_GPT_STATUS_IRQMASK (0x000f) 130 131 #define MPC52xx_GPT_CAN_WDT (1 << 0) 132 #define MPC52xx_GPT_IS_WDT (1 << 1) 133 134 135 /* --------------------------------------------------------------------- 136 * Cascaded interrupt controller hooks 137 */ 138 139 static void mpc52xx_gpt_irq_unmask(struct irq_data *d) 140 { 141 struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); 142 unsigned long flags; 143 144 raw_spin_lock_irqsave(&gpt->lock, flags); 145 setbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN); 146 raw_spin_unlock_irqrestore(&gpt->lock, flags); 147 } 148 149 static void mpc52xx_gpt_irq_mask(struct irq_data *d) 150 { 151 struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); 152 unsigned long flags; 153 154 raw_spin_lock_irqsave(&gpt->lock, flags); 155 clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN); 156 raw_spin_unlock_irqrestore(&gpt->lock, flags); 157 } 158 159 static void mpc52xx_gpt_irq_ack(struct irq_data *d) 160 { 161 struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); 162 163 out_be32(&gpt->regs->status, MPC52xx_GPT_STATUS_IRQMASK); 164 } 165 166 static int mpc52xx_gpt_irq_set_type(struct irq_data *d, unsigned int flow_type) 167 { 168 struct mpc52xx_gpt_priv *gpt = irq_data_get_irq_chip_data(d); 169 unsigned long flags; 170 u32 reg; 171 172 dev_dbg(gpt->dev, "%s: virq=%i type=%x\n", __func__, d->irq, flow_type); 173 174 raw_spin_lock_irqsave(&gpt->lock, flags); 175 reg = in_be32(&gpt->regs->mode) & ~MPC52xx_GPT_MODE_ICT_MASK; 176 if (flow_type & IRQF_TRIGGER_RISING) 177 reg |= MPC52xx_GPT_MODE_ICT_RISING; 178 if (flow_type & IRQF_TRIGGER_FALLING) 179 reg |= MPC52xx_GPT_MODE_ICT_FALLING; 180 out_be32(&gpt->regs->mode, reg); 181 raw_spin_unlock_irqrestore(&gpt->lock, flags); 182 183 return 0; 184 } 185 186 static struct irq_chip mpc52xx_gpt_irq_chip = { 187 .name = "MPC52xx GPT", 188 .irq_unmask = mpc52xx_gpt_irq_unmask, 189 .irq_mask = mpc52xx_gpt_irq_mask, 190 .irq_ack = mpc52xx_gpt_irq_ack, 191 .irq_set_type = mpc52xx_gpt_irq_set_type, 192 }; 193 194 static void mpc52xx_gpt_irq_cascade(struct irq_desc *desc) 195 { 196 struct mpc52xx_gpt_priv *gpt = irq_desc_get_handler_data(desc); 197 int sub_virq; 198 u32 status; 199 200 status = in_be32(&gpt->regs->status) & MPC52xx_GPT_STATUS_IRQMASK; 201 if (status) { 202 sub_virq = irq_linear_revmap(gpt->irqhost, 0); 203 generic_handle_irq(sub_virq); 204 } 205 } 206 207 static int mpc52xx_gpt_irq_map(struct irq_domain *h, unsigned int virq, 208 irq_hw_number_t hw) 209 { 210 struct mpc52xx_gpt_priv *gpt = h->host_data; 211 212 dev_dbg(gpt->dev, "%s: h=%p, virq=%i\n", __func__, h, virq); 213 irq_set_chip_data(virq, gpt); 214 irq_set_chip_and_handler(virq, &mpc52xx_gpt_irq_chip, handle_edge_irq); 215 216 return 0; 217 } 218 219 static int mpc52xx_gpt_irq_xlate(struct irq_domain *h, struct device_node *ct, 220 const u32 *intspec, unsigned int intsize, 221 irq_hw_number_t *out_hwirq, 222 unsigned int *out_flags) 223 { 224 struct mpc52xx_gpt_priv *gpt = h->host_data; 225 226 dev_dbg(gpt->dev, "%s: flags=%i\n", __func__, intspec[0]); 227 228 if ((intsize < 1) || (intspec[0] > 3)) { 229 dev_err(gpt->dev, "bad irq specifier in %pOF\n", ct); 230 return -EINVAL; 231 } 232 233 *out_hwirq = 0; /* The GPT only has 1 IRQ line */ 234 *out_flags = intspec[0]; 235 236 return 0; 237 } 238 239 static const struct irq_domain_ops mpc52xx_gpt_irq_ops = { 240 .map = mpc52xx_gpt_irq_map, 241 .xlate = mpc52xx_gpt_irq_xlate, 242 }; 243 244 static void 245 mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node) 246 { 247 int cascade_virq; 248 unsigned long flags; 249 u32 mode; 250 251 cascade_virq = irq_of_parse_and_map(node, 0); 252 if (!cascade_virq) 253 return; 254 255 gpt->irqhost = irq_domain_add_linear(node, 1, &mpc52xx_gpt_irq_ops, gpt); 256 if (!gpt->irqhost) { 257 dev_err(gpt->dev, "irq_domain_add_linear() failed\n"); 258 return; 259 } 260 261 irq_set_handler_data(cascade_virq, gpt); 262 irq_set_chained_handler(cascade_virq, mpc52xx_gpt_irq_cascade); 263 264 /* If the GPT is currently disabled, then change it to be in Input 265 * Capture mode. If the mode is non-zero, then the pin could be 266 * already in use for something. */ 267 raw_spin_lock_irqsave(&gpt->lock, flags); 268 mode = in_be32(&gpt->regs->mode); 269 if ((mode & MPC52xx_GPT_MODE_MS_MASK) == 0) 270 out_be32(&gpt->regs->mode, mode | MPC52xx_GPT_MODE_MS_IC); 271 raw_spin_unlock_irqrestore(&gpt->lock, flags); 272 273 dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq); 274 } 275 276 277 /* --------------------------------------------------------------------- 278 * GPIOLIB hooks 279 */ 280 #if defined(CONFIG_GPIOLIB) 281 static int mpc52xx_gpt_gpio_get(struct gpio_chip *gc, unsigned int gpio) 282 { 283 struct mpc52xx_gpt_priv *gpt = gpiochip_get_data(gc); 284 285 return (in_be32(&gpt->regs->status) >> 8) & 1; 286 } 287 288 static void 289 mpc52xx_gpt_gpio_set(struct gpio_chip *gc, unsigned int gpio, int v) 290 { 291 struct mpc52xx_gpt_priv *gpt = gpiochip_get_data(gc); 292 unsigned long flags; 293 u32 r; 294 295 dev_dbg(gpt->dev, "%s: gpio:%d v:%d\n", __func__, gpio, v); 296 r = v ? MPC52xx_GPT_MODE_GPIO_OUT_HIGH : MPC52xx_GPT_MODE_GPIO_OUT_LOW; 297 298 raw_spin_lock_irqsave(&gpt->lock, flags); 299 clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK, r); 300 raw_spin_unlock_irqrestore(&gpt->lock, flags); 301 } 302 303 static int mpc52xx_gpt_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio) 304 { 305 struct mpc52xx_gpt_priv *gpt = gpiochip_get_data(gc); 306 unsigned long flags; 307 308 dev_dbg(gpt->dev, "%s: gpio:%d\n", __func__, gpio); 309 310 raw_spin_lock_irqsave(&gpt->lock, flags); 311 clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK); 312 raw_spin_unlock_irqrestore(&gpt->lock, flags); 313 314 return 0; 315 } 316 317 static int 318 mpc52xx_gpt_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) 319 { 320 mpc52xx_gpt_gpio_set(gc, gpio, val); 321 return 0; 322 } 323 324 static void 325 mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node) 326 { 327 int rc; 328 329 /* Only setup GPIO if the device tree claims the GPT is 330 * a GPIO controller */ 331 if (!of_find_property(node, "gpio-controller", NULL)) 332 return; 333 334 gpt->gc.label = kasprintf(GFP_KERNEL, "%pOF", node); 335 if (!gpt->gc.label) { 336 dev_err(gpt->dev, "out of memory\n"); 337 return; 338 } 339 340 gpt->gc.ngpio = 1; 341 gpt->gc.direction_input = mpc52xx_gpt_gpio_dir_in; 342 gpt->gc.direction_output = mpc52xx_gpt_gpio_dir_out; 343 gpt->gc.get = mpc52xx_gpt_gpio_get; 344 gpt->gc.set = mpc52xx_gpt_gpio_set; 345 gpt->gc.base = -1; 346 gpt->gc.of_node = node; 347 348 /* Setup external pin in GPIO mode */ 349 clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK, 350 MPC52xx_GPT_MODE_MS_GPIO); 351 352 rc = gpiochip_add_data(&gpt->gc, gpt); 353 if (rc) 354 dev_err(gpt->dev, "gpiochip_add_data() failed; rc=%i\n", rc); 355 356 dev_dbg(gpt->dev, "%s() complete.\n", __func__); 357 } 358 #else /* defined(CONFIG_GPIOLIB) */ 359 static void 360 mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *p, struct device_node *np) { } 361 #endif /* defined(CONFIG_GPIOLIB) */ 362 363 /*********************************************************************** 364 * Timer API 365 */ 366 367 /** 368 * mpc52xx_gpt_from_irq - Return the GPT device associated with an IRQ number 369 * @irq: irq of timer. 370 */ 371 struct mpc52xx_gpt_priv *mpc52xx_gpt_from_irq(int irq) 372 { 373 struct mpc52xx_gpt_priv *gpt; 374 struct list_head *pos; 375 376 /* Iterate over the list of timers looking for a matching device */ 377 mutex_lock(&mpc52xx_gpt_list_mutex); 378 list_for_each(pos, &mpc52xx_gpt_list) { 379 gpt = container_of(pos, struct mpc52xx_gpt_priv, list); 380 if (gpt->irqhost && irq == irq_linear_revmap(gpt->irqhost, 0)) { 381 mutex_unlock(&mpc52xx_gpt_list_mutex); 382 return gpt; 383 } 384 } 385 mutex_unlock(&mpc52xx_gpt_list_mutex); 386 387 return NULL; 388 } 389 EXPORT_SYMBOL(mpc52xx_gpt_from_irq); 390 391 static int mpc52xx_gpt_do_start(struct mpc52xx_gpt_priv *gpt, u64 period, 392 int continuous, int as_wdt) 393 { 394 u32 clear, set; 395 u64 clocks; 396 u32 prescale; 397 unsigned long flags; 398 399 clear = MPC52xx_GPT_MODE_MS_MASK | MPC52xx_GPT_MODE_CONTINUOUS; 400 set = MPC52xx_GPT_MODE_MS_GPIO | MPC52xx_GPT_MODE_COUNTER_ENABLE; 401 if (as_wdt) { 402 clear |= MPC52xx_GPT_MODE_IRQ_EN; 403 set |= MPC52xx_GPT_MODE_WDT_EN; 404 } else if (continuous) 405 set |= MPC52xx_GPT_MODE_CONTINUOUS; 406 407 /* Determine the number of clocks in the requested period. 64 bit 408 * arithmatic is done here to preserve the precision until the value 409 * is scaled back down into the u32 range. Period is in 'ns', bus 410 * frequency is in Hz. */ 411 clocks = period * (u64)gpt->ipb_freq; 412 do_div(clocks, 1000000000); /* Scale it down to ns range */ 413 414 /* This device cannot handle a clock count greater than 32 bits */ 415 if (clocks > 0xffffffff) 416 return -EINVAL; 417 418 /* Calculate the prescaler and count values from the clocks value. 419 * 'clocks' is the number of clock ticks in the period. The timer 420 * has 16 bit precision and a 16 bit prescaler. Prescaler is 421 * calculated by integer dividing the clocks by 0x10000 (shifting 422 * down 16 bits) to obtain the smallest possible divisor for clocks 423 * to get a 16 bit count value. 424 * 425 * Note: the prescale register is '1' based, not '0' based. ie. a 426 * value of '1' means divide the clock by one. 0xffff divides the 427 * clock by 0xffff. '0x0000' does not divide by zero, but wraps 428 * around and divides by 0x10000. That is why prescale must be 429 * a u32 variable, not a u16, for this calculation. */ 430 prescale = (clocks >> 16) + 1; 431 do_div(clocks, prescale); 432 if (clocks > 0xffff) { 433 pr_err("calculation error; prescale:%x clocks:%llx\n", 434 prescale, clocks); 435 return -EINVAL; 436 } 437 438 /* Set and enable the timer, reject an attempt to use a wdt as gpt */ 439 raw_spin_lock_irqsave(&gpt->lock, flags); 440 if (as_wdt) 441 gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; 442 else if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { 443 raw_spin_unlock_irqrestore(&gpt->lock, flags); 444 return -EBUSY; 445 } 446 out_be32(&gpt->regs->count, prescale << 16 | clocks); 447 clrsetbits_be32(&gpt->regs->mode, clear, set); 448 raw_spin_unlock_irqrestore(&gpt->lock, flags); 449 450 return 0; 451 } 452 453 /** 454 * mpc52xx_gpt_start_timer - Set and enable the GPT timer 455 * @gpt: Pointer to gpt private data structure 456 * @period: period of timer in ns; max. ~130s @ 33MHz IPB clock 457 * @continuous: set to 1 to make timer continuous free running 458 * 459 * An interrupt will be generated every time the timer fires 460 */ 461 int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, u64 period, 462 int continuous) 463 { 464 return mpc52xx_gpt_do_start(gpt, period, continuous, 0); 465 } 466 EXPORT_SYMBOL(mpc52xx_gpt_start_timer); 467 468 /** 469 * mpc52xx_gpt_stop_timer - Stop a gpt 470 * @gpt: Pointer to gpt private data structure 471 * 472 * Returns an error if attempting to stop a wdt 473 */ 474 int mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt) 475 { 476 unsigned long flags; 477 478 /* reject the operation if the timer is used as watchdog (gpt 0 only) */ 479 raw_spin_lock_irqsave(&gpt->lock, flags); 480 if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { 481 raw_spin_unlock_irqrestore(&gpt->lock, flags); 482 return -EBUSY; 483 } 484 485 clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_COUNTER_ENABLE); 486 raw_spin_unlock_irqrestore(&gpt->lock, flags); 487 return 0; 488 } 489 EXPORT_SYMBOL(mpc52xx_gpt_stop_timer); 490 491 /** 492 * mpc52xx_gpt_timer_period - Read the timer period 493 * @gpt: Pointer to gpt private data structure 494 * 495 * Returns the timer period in ns 496 */ 497 u64 mpc52xx_gpt_timer_period(struct mpc52xx_gpt_priv *gpt) 498 { 499 u64 period; 500 u64 prescale; 501 unsigned long flags; 502 503 raw_spin_lock_irqsave(&gpt->lock, flags); 504 period = in_be32(&gpt->regs->count); 505 raw_spin_unlock_irqrestore(&gpt->lock, flags); 506 507 prescale = period >> 16; 508 period &= 0xffff; 509 if (prescale == 0) 510 prescale = 0x10000; 511 period = period * prescale * 1000000000ULL; 512 do_div(period, (u64)gpt->ipb_freq); 513 return period; 514 } 515 EXPORT_SYMBOL(mpc52xx_gpt_timer_period); 516 517 #if defined(CONFIG_MPC5200_WDT) 518 /*********************************************************************** 519 * Watchdog API for gpt0 520 */ 521 522 #define WDT_IDENTITY "mpc52xx watchdog on GPT0" 523 524 /* wdt_is_active stores whether or not the /dev/watchdog device is opened */ 525 static unsigned long wdt_is_active; 526 527 /* wdt-capable gpt */ 528 static struct mpc52xx_gpt_priv *mpc52xx_gpt_wdt; 529 530 /* low-level wdt functions */ 531 static inline void mpc52xx_gpt_wdt_ping(struct mpc52xx_gpt_priv *gpt_wdt) 532 { 533 unsigned long flags; 534 535 raw_spin_lock_irqsave(&gpt_wdt->lock, flags); 536 out_8((u8 *) &gpt_wdt->regs->mode, MPC52xx_GPT_MODE_WDT_PING); 537 raw_spin_unlock_irqrestore(&gpt_wdt->lock, flags); 538 } 539 540 /* wdt misc device api */ 541 static ssize_t mpc52xx_wdt_write(struct file *file, const char __user *data, 542 size_t len, loff_t *ppos) 543 { 544 struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; 545 mpc52xx_gpt_wdt_ping(gpt_wdt); 546 return 0; 547 } 548 549 static const struct watchdog_info mpc5200_wdt_info = { 550 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 551 .identity = WDT_IDENTITY, 552 }; 553 554 static long mpc52xx_wdt_ioctl(struct file *file, unsigned int cmd, 555 unsigned long arg) 556 { 557 struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; 558 int __user *data = (int __user *)arg; 559 int timeout; 560 u64 real_timeout; 561 int ret = 0; 562 563 switch (cmd) { 564 case WDIOC_GETSUPPORT: 565 ret = copy_to_user(data, &mpc5200_wdt_info, 566 sizeof(mpc5200_wdt_info)); 567 if (ret) 568 ret = -EFAULT; 569 break; 570 571 case WDIOC_GETSTATUS: 572 case WDIOC_GETBOOTSTATUS: 573 ret = put_user(0, data); 574 break; 575 576 case WDIOC_KEEPALIVE: 577 mpc52xx_gpt_wdt_ping(gpt_wdt); 578 break; 579 580 case WDIOC_SETTIMEOUT: 581 ret = get_user(timeout, data); 582 if (ret) 583 break; 584 real_timeout = (u64) timeout * 1000000000ULL; 585 ret = mpc52xx_gpt_do_start(gpt_wdt, real_timeout, 0, 1); 586 if (ret) 587 break; 588 /* fall through and return the timeout */ 589 590 case WDIOC_GETTIMEOUT: 591 /* we need to round here as to avoid e.g. the following 592 * situation: 593 * - timeout requested is 1 second; 594 * - real timeout @33MHz is 999997090ns 595 * - the int divide by 10^9 will return 0. 596 */ 597 real_timeout = 598 mpc52xx_gpt_timer_period(gpt_wdt) + 500000000ULL; 599 do_div(real_timeout, 1000000000ULL); 600 timeout = (int) real_timeout; 601 ret = put_user(timeout, data); 602 break; 603 604 default: 605 ret = -ENOTTY; 606 } 607 return ret; 608 } 609 610 static int mpc52xx_wdt_open(struct inode *inode, struct file *file) 611 { 612 int ret; 613 614 /* sanity check */ 615 if (!mpc52xx_gpt_wdt) 616 return -ENODEV; 617 618 /* /dev/watchdog can only be opened once */ 619 if (test_and_set_bit(0, &wdt_is_active)) 620 return -EBUSY; 621 622 /* Set and activate the watchdog with 30 seconds timeout */ 623 ret = mpc52xx_gpt_do_start(mpc52xx_gpt_wdt, 30ULL * 1000000000ULL, 624 0, 1); 625 if (ret) { 626 clear_bit(0, &wdt_is_active); 627 return ret; 628 } 629 630 file->private_data = mpc52xx_gpt_wdt; 631 return nonseekable_open(inode, file); 632 } 633 634 static int mpc52xx_wdt_release(struct inode *inode, struct file *file) 635 { 636 /* note: releasing the wdt in NOWAYOUT-mode does not stop it */ 637 #if !defined(CONFIG_WATCHDOG_NOWAYOUT) 638 struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; 639 unsigned long flags; 640 641 raw_spin_lock_irqsave(&gpt_wdt->lock, flags); 642 clrbits32(&gpt_wdt->regs->mode, 643 MPC52xx_GPT_MODE_COUNTER_ENABLE | MPC52xx_GPT_MODE_WDT_EN); 644 gpt_wdt->wdt_mode &= ~MPC52xx_GPT_IS_WDT; 645 raw_spin_unlock_irqrestore(&gpt_wdt->lock, flags); 646 #endif 647 clear_bit(0, &wdt_is_active); 648 return 0; 649 } 650 651 652 static const struct file_operations mpc52xx_wdt_fops = { 653 .owner = THIS_MODULE, 654 .llseek = no_llseek, 655 .write = mpc52xx_wdt_write, 656 .unlocked_ioctl = mpc52xx_wdt_ioctl, 657 .open = mpc52xx_wdt_open, 658 .release = mpc52xx_wdt_release, 659 }; 660 661 static struct miscdevice mpc52xx_wdt_miscdev = { 662 .minor = WATCHDOG_MINOR, 663 .name = "watchdog", 664 .fops = &mpc52xx_wdt_fops, 665 }; 666 667 static int mpc52xx_gpt_wdt_init(void) 668 { 669 int err; 670 671 /* try to register the watchdog misc device */ 672 err = misc_register(&mpc52xx_wdt_miscdev); 673 if (err) 674 pr_err("%s: cannot register watchdog device\n", WDT_IDENTITY); 675 else 676 pr_info("%s: watchdog device registered\n", WDT_IDENTITY); 677 return err; 678 } 679 680 static int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt, 681 const u32 *period) 682 { 683 u64 real_timeout; 684 685 /* remember the gpt for the wdt operation */ 686 mpc52xx_gpt_wdt = gpt; 687 688 /* configure the wdt if the device tree contained a timeout */ 689 if (!period || *period == 0) 690 return 0; 691 692 real_timeout = (u64) *period * 1000000000ULL; 693 if (mpc52xx_gpt_do_start(gpt, real_timeout, 0, 1)) 694 dev_warn(gpt->dev, "starting as wdt failed\n"); 695 else 696 dev_info(gpt->dev, "watchdog set to %us timeout\n", *period); 697 return 0; 698 } 699 700 #else 701 702 static int mpc52xx_gpt_wdt_init(void) 703 { 704 return 0; 705 } 706 707 static inline int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt, 708 const u32 *period) 709 { 710 return 0; 711 } 712 713 #endif /* CONFIG_MPC5200_WDT */ 714 715 /* --------------------------------------------------------------------- 716 * of_platform bus binding code 717 */ 718 static int mpc52xx_gpt_probe(struct platform_device *ofdev) 719 { 720 struct mpc52xx_gpt_priv *gpt; 721 722 gpt = devm_kzalloc(&ofdev->dev, sizeof *gpt, GFP_KERNEL); 723 if (!gpt) 724 return -ENOMEM; 725 726 raw_spin_lock_init(&gpt->lock); 727 gpt->dev = &ofdev->dev; 728 gpt->ipb_freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node); 729 gpt->regs = of_iomap(ofdev->dev.of_node, 0); 730 if (!gpt->regs) 731 return -ENOMEM; 732 733 dev_set_drvdata(&ofdev->dev, gpt); 734 735 mpc52xx_gpt_gpio_setup(gpt, ofdev->dev.of_node); 736 mpc52xx_gpt_irq_setup(gpt, ofdev->dev.of_node); 737 738 mutex_lock(&mpc52xx_gpt_list_mutex); 739 list_add(&gpt->list, &mpc52xx_gpt_list); 740 mutex_unlock(&mpc52xx_gpt_list_mutex); 741 742 /* check if this device could be a watchdog */ 743 if (of_get_property(ofdev->dev.of_node, "fsl,has-wdt", NULL) || 744 of_get_property(ofdev->dev.of_node, "has-wdt", NULL)) { 745 const u32 *on_boot_wdt; 746 747 gpt->wdt_mode = MPC52xx_GPT_CAN_WDT; 748 on_boot_wdt = of_get_property(ofdev->dev.of_node, 749 "fsl,wdt-on-boot", NULL); 750 if (on_boot_wdt) { 751 dev_info(gpt->dev, "used as watchdog\n"); 752 gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; 753 } else 754 dev_info(gpt->dev, "can function as watchdog\n"); 755 mpc52xx_gpt_wdt_setup(gpt, on_boot_wdt); 756 } 757 758 return 0; 759 } 760 761 static int mpc52xx_gpt_remove(struct platform_device *ofdev) 762 { 763 return -EBUSY; 764 } 765 766 static const struct of_device_id mpc52xx_gpt_match[] = { 767 { .compatible = "fsl,mpc5200-gpt", }, 768 769 /* Depreciated compatible values; don't use for new dts files */ 770 { .compatible = "fsl,mpc5200-gpt-gpio", }, 771 { .compatible = "mpc5200-gpt", }, 772 {} 773 }; 774 775 static struct platform_driver mpc52xx_gpt_driver = { 776 .driver = { 777 .name = "mpc52xx-gpt", 778 .of_match_table = mpc52xx_gpt_match, 779 }, 780 .probe = mpc52xx_gpt_probe, 781 .remove = mpc52xx_gpt_remove, 782 }; 783 784 static int __init mpc52xx_gpt_init(void) 785 { 786 return platform_driver_register(&mpc52xx_gpt_driver); 787 } 788 789 /* Make sure GPIOs and IRQs get set up before anyone tries to use them */ 790 subsys_initcall(mpc52xx_gpt_init); 791 device_initcall(mpc52xx_gpt_wdt_init); 792