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 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 spin_lock_irqsave(&gpt->lock, flags); 145 setbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN); 146 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 spin_lock_irqsave(&gpt->lock, flags); 155 clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_IRQ_EN); 156 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 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 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 void mpc52xx_gpt_irq_cascade(unsigned int virq, struct irq_desc *desc) 195 { 196 struct mpc52xx_gpt_priv *gpt = irq_get_handler_data(virq); 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 %s\n", ct->full_name); 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 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 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 inline struct mpc52xx_gpt_priv *gc_to_mpc52xx_gpt(struct gpio_chip *gc) 282 { 283 return container_of(gc, struct mpc52xx_gpt_priv, gc); 284 } 285 286 static int mpc52xx_gpt_gpio_get(struct gpio_chip *gc, unsigned int gpio) 287 { 288 struct mpc52xx_gpt_priv *gpt = gc_to_mpc52xx_gpt(gc); 289 290 return (in_be32(&gpt->regs->status) >> 8) & 1; 291 } 292 293 static void 294 mpc52xx_gpt_gpio_set(struct gpio_chip *gc, unsigned int gpio, int v) 295 { 296 struct mpc52xx_gpt_priv *gpt = gc_to_mpc52xx_gpt(gc); 297 unsigned long flags; 298 u32 r; 299 300 dev_dbg(gpt->dev, "%s: gpio:%d v:%d\n", __func__, gpio, v); 301 r = v ? MPC52xx_GPT_MODE_GPIO_OUT_HIGH : MPC52xx_GPT_MODE_GPIO_OUT_LOW; 302 303 spin_lock_irqsave(&gpt->lock, flags); 304 clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK, r); 305 spin_unlock_irqrestore(&gpt->lock, flags); 306 } 307 308 static int mpc52xx_gpt_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio) 309 { 310 struct mpc52xx_gpt_priv *gpt = gc_to_mpc52xx_gpt(gc); 311 unsigned long flags; 312 313 dev_dbg(gpt->dev, "%s: gpio:%d\n", __func__, gpio); 314 315 spin_lock_irqsave(&gpt->lock, flags); 316 clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_GPIO_MASK); 317 spin_unlock_irqrestore(&gpt->lock, flags); 318 319 return 0; 320 } 321 322 static int 323 mpc52xx_gpt_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) 324 { 325 mpc52xx_gpt_gpio_set(gc, gpio, val); 326 return 0; 327 } 328 329 static void 330 mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node) 331 { 332 int rc; 333 334 /* Only setup GPIO if the device tree claims the GPT is 335 * a GPIO controller */ 336 if (!of_find_property(node, "gpio-controller", NULL)) 337 return; 338 339 gpt->gc.label = kstrdup(node->full_name, GFP_KERNEL); 340 if (!gpt->gc.label) { 341 dev_err(gpt->dev, "out of memory\n"); 342 return; 343 } 344 345 gpt->gc.ngpio = 1; 346 gpt->gc.direction_input = mpc52xx_gpt_gpio_dir_in; 347 gpt->gc.direction_output = mpc52xx_gpt_gpio_dir_out; 348 gpt->gc.get = mpc52xx_gpt_gpio_get; 349 gpt->gc.set = mpc52xx_gpt_gpio_set; 350 gpt->gc.base = -1; 351 gpt->gc.of_node = node; 352 353 /* Setup external pin in GPIO mode */ 354 clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK, 355 MPC52xx_GPT_MODE_MS_GPIO); 356 357 rc = gpiochip_add(&gpt->gc); 358 if (rc) 359 dev_err(gpt->dev, "gpiochip_add() failed; rc=%i\n", rc); 360 361 dev_dbg(gpt->dev, "%s() complete.\n", __func__); 362 } 363 #else /* defined(CONFIG_GPIOLIB) */ 364 static void 365 mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *p, struct device_node *np) { } 366 #endif /* defined(CONFIG_GPIOLIB) */ 367 368 /*********************************************************************** 369 * Timer API 370 */ 371 372 /** 373 * mpc52xx_gpt_from_irq - Return the GPT device associated with an IRQ number 374 * @irq: irq of timer. 375 */ 376 struct mpc52xx_gpt_priv *mpc52xx_gpt_from_irq(int irq) 377 { 378 struct mpc52xx_gpt_priv *gpt; 379 struct list_head *pos; 380 381 /* Iterate over the list of timers looking for a matching device */ 382 mutex_lock(&mpc52xx_gpt_list_mutex); 383 list_for_each(pos, &mpc52xx_gpt_list) { 384 gpt = container_of(pos, struct mpc52xx_gpt_priv, list); 385 if (gpt->irqhost && irq == irq_linear_revmap(gpt->irqhost, 0)) { 386 mutex_unlock(&mpc52xx_gpt_list_mutex); 387 return gpt; 388 } 389 } 390 mutex_unlock(&mpc52xx_gpt_list_mutex); 391 392 return NULL; 393 } 394 EXPORT_SYMBOL(mpc52xx_gpt_from_irq); 395 396 static int mpc52xx_gpt_do_start(struct mpc52xx_gpt_priv *gpt, u64 period, 397 int continuous, int as_wdt) 398 { 399 u32 clear, set; 400 u64 clocks; 401 u32 prescale; 402 unsigned long flags; 403 404 clear = MPC52xx_GPT_MODE_MS_MASK | MPC52xx_GPT_MODE_CONTINUOUS; 405 set = MPC52xx_GPT_MODE_MS_GPIO | MPC52xx_GPT_MODE_COUNTER_ENABLE; 406 if (as_wdt) { 407 clear |= MPC52xx_GPT_MODE_IRQ_EN; 408 set |= MPC52xx_GPT_MODE_WDT_EN; 409 } else if (continuous) 410 set |= MPC52xx_GPT_MODE_CONTINUOUS; 411 412 /* Determine the number of clocks in the requested period. 64 bit 413 * arithmatic is done here to preserve the precision until the value 414 * is scaled back down into the u32 range. Period is in 'ns', bus 415 * frequency is in Hz. */ 416 clocks = period * (u64)gpt->ipb_freq; 417 do_div(clocks, 1000000000); /* Scale it down to ns range */ 418 419 /* This device cannot handle a clock count greater than 32 bits */ 420 if (clocks > 0xffffffff) 421 return -EINVAL; 422 423 /* Calculate the prescaler and count values from the clocks value. 424 * 'clocks' is the number of clock ticks in the period. The timer 425 * has 16 bit precision and a 16 bit prescaler. Prescaler is 426 * calculated by integer dividing the clocks by 0x10000 (shifting 427 * down 16 bits) to obtain the smallest possible divisor for clocks 428 * to get a 16 bit count value. 429 * 430 * Note: the prescale register is '1' based, not '0' based. ie. a 431 * value of '1' means divide the clock by one. 0xffff divides the 432 * clock by 0xffff. '0x0000' does not divide by zero, but wraps 433 * around and divides by 0x10000. That is why prescale must be 434 * a u32 variable, not a u16, for this calculation. */ 435 prescale = (clocks >> 16) + 1; 436 do_div(clocks, prescale); 437 if (clocks > 0xffff) { 438 pr_err("calculation error; prescale:%x clocks:%llx\n", 439 prescale, clocks); 440 return -EINVAL; 441 } 442 443 /* Set and enable the timer, reject an attempt to use a wdt as gpt */ 444 spin_lock_irqsave(&gpt->lock, flags); 445 if (as_wdt) 446 gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; 447 else if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { 448 spin_unlock_irqrestore(&gpt->lock, flags); 449 return -EBUSY; 450 } 451 out_be32(&gpt->regs->count, prescale << 16 | clocks); 452 clrsetbits_be32(&gpt->regs->mode, clear, set); 453 spin_unlock_irqrestore(&gpt->lock, flags); 454 455 return 0; 456 } 457 458 /** 459 * mpc52xx_gpt_start_timer - Set and enable the GPT timer 460 * @gpt: Pointer to gpt private data structure 461 * @period: period of timer in ns; max. ~130s @ 33MHz IPB clock 462 * @continuous: set to 1 to make timer continuous free running 463 * 464 * An interrupt will be generated every time the timer fires 465 */ 466 int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, u64 period, 467 int continuous) 468 { 469 return mpc52xx_gpt_do_start(gpt, period, continuous, 0); 470 } 471 EXPORT_SYMBOL(mpc52xx_gpt_start_timer); 472 473 /** 474 * mpc52xx_gpt_stop_timer - Stop a gpt 475 * @gpt: Pointer to gpt private data structure 476 * 477 * Returns an error if attempting to stop a wdt 478 */ 479 int mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt) 480 { 481 unsigned long flags; 482 483 /* reject the operation if the timer is used as watchdog (gpt 0 only) */ 484 spin_lock_irqsave(&gpt->lock, flags); 485 if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) { 486 spin_unlock_irqrestore(&gpt->lock, flags); 487 return -EBUSY; 488 } 489 490 clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_COUNTER_ENABLE); 491 spin_unlock_irqrestore(&gpt->lock, flags); 492 return 0; 493 } 494 EXPORT_SYMBOL(mpc52xx_gpt_stop_timer); 495 496 /** 497 * mpc52xx_gpt_timer_period - Read the timer period 498 * @gpt: Pointer to gpt private data structure 499 * 500 * Returns the timer period in ns 501 */ 502 u64 mpc52xx_gpt_timer_period(struct mpc52xx_gpt_priv *gpt) 503 { 504 u64 period; 505 u64 prescale; 506 unsigned long flags; 507 508 spin_lock_irqsave(&gpt->lock, flags); 509 period = in_be32(&gpt->regs->count); 510 spin_unlock_irqrestore(&gpt->lock, flags); 511 512 prescale = period >> 16; 513 period &= 0xffff; 514 if (prescale == 0) 515 prescale = 0x10000; 516 period = period * prescale * 1000000000ULL; 517 do_div(period, (u64)gpt->ipb_freq); 518 return period; 519 } 520 EXPORT_SYMBOL(mpc52xx_gpt_timer_period); 521 522 #if defined(CONFIG_MPC5200_WDT) 523 /*********************************************************************** 524 * Watchdog API for gpt0 525 */ 526 527 #define WDT_IDENTITY "mpc52xx watchdog on GPT0" 528 529 /* wdt_is_active stores wether or not the /dev/watchdog device is opened */ 530 static unsigned long wdt_is_active; 531 532 /* wdt-capable gpt */ 533 static struct mpc52xx_gpt_priv *mpc52xx_gpt_wdt; 534 535 /* low-level wdt functions */ 536 static inline void mpc52xx_gpt_wdt_ping(struct mpc52xx_gpt_priv *gpt_wdt) 537 { 538 unsigned long flags; 539 540 spin_lock_irqsave(&gpt_wdt->lock, flags); 541 out_8((u8 *) &gpt_wdt->regs->mode, MPC52xx_GPT_MODE_WDT_PING); 542 spin_unlock_irqrestore(&gpt_wdt->lock, flags); 543 } 544 545 /* wdt misc device api */ 546 static ssize_t mpc52xx_wdt_write(struct file *file, const char __user *data, 547 size_t len, loff_t *ppos) 548 { 549 struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; 550 mpc52xx_gpt_wdt_ping(gpt_wdt); 551 return 0; 552 } 553 554 static const struct watchdog_info mpc5200_wdt_info = { 555 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, 556 .identity = WDT_IDENTITY, 557 }; 558 559 static long mpc52xx_wdt_ioctl(struct file *file, unsigned int cmd, 560 unsigned long arg) 561 { 562 struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; 563 int __user *data = (int __user *)arg; 564 int timeout; 565 u64 real_timeout; 566 int ret = 0; 567 568 switch (cmd) { 569 case WDIOC_GETSUPPORT: 570 ret = copy_to_user(data, &mpc5200_wdt_info, 571 sizeof(mpc5200_wdt_info)); 572 if (ret) 573 ret = -EFAULT; 574 break; 575 576 case WDIOC_GETSTATUS: 577 case WDIOC_GETBOOTSTATUS: 578 ret = put_user(0, data); 579 break; 580 581 case WDIOC_KEEPALIVE: 582 mpc52xx_gpt_wdt_ping(gpt_wdt); 583 break; 584 585 case WDIOC_SETTIMEOUT: 586 ret = get_user(timeout, data); 587 if (ret) 588 break; 589 real_timeout = (u64) timeout * 1000000000ULL; 590 ret = mpc52xx_gpt_do_start(gpt_wdt, real_timeout, 0, 1); 591 if (ret) 592 break; 593 /* fall through and return the timeout */ 594 595 case WDIOC_GETTIMEOUT: 596 /* we need to round here as to avoid e.g. the following 597 * situation: 598 * - timeout requested is 1 second; 599 * - real timeout @33MHz is 999997090ns 600 * - the int divide by 10^9 will return 0. 601 */ 602 real_timeout = 603 mpc52xx_gpt_timer_period(gpt_wdt) + 500000000ULL; 604 do_div(real_timeout, 1000000000ULL); 605 timeout = (int) real_timeout; 606 ret = put_user(timeout, data); 607 break; 608 609 default: 610 ret = -ENOTTY; 611 } 612 return ret; 613 } 614 615 static int mpc52xx_wdt_open(struct inode *inode, struct file *file) 616 { 617 int ret; 618 619 /* sanity check */ 620 if (!mpc52xx_gpt_wdt) 621 return -ENODEV; 622 623 /* /dev/watchdog can only be opened once */ 624 if (test_and_set_bit(0, &wdt_is_active)) 625 return -EBUSY; 626 627 /* Set and activate the watchdog with 30 seconds timeout */ 628 ret = mpc52xx_gpt_do_start(mpc52xx_gpt_wdt, 30ULL * 1000000000ULL, 629 0, 1); 630 if (ret) { 631 clear_bit(0, &wdt_is_active); 632 return ret; 633 } 634 635 file->private_data = mpc52xx_gpt_wdt; 636 return nonseekable_open(inode, file); 637 } 638 639 static int mpc52xx_wdt_release(struct inode *inode, struct file *file) 640 { 641 /* note: releasing the wdt in NOWAYOUT-mode does not stop it */ 642 #if !defined(CONFIG_WATCHDOG_NOWAYOUT) 643 struct mpc52xx_gpt_priv *gpt_wdt = file->private_data; 644 unsigned long flags; 645 646 spin_lock_irqsave(&gpt_wdt->lock, flags); 647 clrbits32(&gpt_wdt->regs->mode, 648 MPC52xx_GPT_MODE_COUNTER_ENABLE | MPC52xx_GPT_MODE_WDT_EN); 649 gpt_wdt->wdt_mode &= ~MPC52xx_GPT_IS_WDT; 650 spin_unlock_irqrestore(&gpt_wdt->lock, flags); 651 #endif 652 clear_bit(0, &wdt_is_active); 653 return 0; 654 } 655 656 657 static const struct file_operations mpc52xx_wdt_fops = { 658 .owner = THIS_MODULE, 659 .llseek = no_llseek, 660 .write = mpc52xx_wdt_write, 661 .unlocked_ioctl = mpc52xx_wdt_ioctl, 662 .open = mpc52xx_wdt_open, 663 .release = mpc52xx_wdt_release, 664 }; 665 666 static struct miscdevice mpc52xx_wdt_miscdev = { 667 .minor = WATCHDOG_MINOR, 668 .name = "watchdog", 669 .fops = &mpc52xx_wdt_fops, 670 }; 671 672 static int __devinit mpc52xx_gpt_wdt_init(void) 673 { 674 int err; 675 676 /* try to register the watchdog misc device */ 677 err = misc_register(&mpc52xx_wdt_miscdev); 678 if (err) 679 pr_err("%s: cannot register watchdog device\n", WDT_IDENTITY); 680 else 681 pr_info("%s: watchdog device registered\n", WDT_IDENTITY); 682 return err; 683 } 684 685 static int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt, 686 const u32 *period) 687 { 688 u64 real_timeout; 689 690 /* remember the gpt for the wdt operation */ 691 mpc52xx_gpt_wdt = gpt; 692 693 /* configure the wdt if the device tree contained a timeout */ 694 if (!period || *period == 0) 695 return 0; 696 697 real_timeout = (u64) *period * 1000000000ULL; 698 if (mpc52xx_gpt_do_start(gpt, real_timeout, 0, 1)) 699 dev_warn(gpt->dev, "starting as wdt failed\n"); 700 else 701 dev_info(gpt->dev, "watchdog set to %us timeout\n", *period); 702 return 0; 703 } 704 705 #else 706 707 static int __devinit mpc52xx_gpt_wdt_init(void) 708 { 709 return 0; 710 } 711 712 static inline int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt, 713 const u32 *period) 714 { 715 return 0; 716 } 717 718 #endif /* CONFIG_MPC5200_WDT */ 719 720 /* --------------------------------------------------------------------- 721 * of_platform bus binding code 722 */ 723 static int __devinit mpc52xx_gpt_probe(struct platform_device *ofdev) 724 { 725 struct mpc52xx_gpt_priv *gpt; 726 727 gpt = kzalloc(sizeof *gpt, GFP_KERNEL); 728 if (!gpt) 729 return -ENOMEM; 730 731 spin_lock_init(&gpt->lock); 732 gpt->dev = &ofdev->dev; 733 gpt->ipb_freq = mpc5xxx_get_bus_frequency(ofdev->dev.of_node); 734 gpt->regs = of_iomap(ofdev->dev.of_node, 0); 735 if (!gpt->regs) { 736 kfree(gpt); 737 return -ENOMEM; 738 } 739 740 dev_set_drvdata(&ofdev->dev, gpt); 741 742 mpc52xx_gpt_gpio_setup(gpt, ofdev->dev.of_node); 743 mpc52xx_gpt_irq_setup(gpt, ofdev->dev.of_node); 744 745 mutex_lock(&mpc52xx_gpt_list_mutex); 746 list_add(&gpt->list, &mpc52xx_gpt_list); 747 mutex_unlock(&mpc52xx_gpt_list_mutex); 748 749 /* check if this device could be a watchdog */ 750 if (of_get_property(ofdev->dev.of_node, "fsl,has-wdt", NULL) || 751 of_get_property(ofdev->dev.of_node, "has-wdt", NULL)) { 752 const u32 *on_boot_wdt; 753 754 gpt->wdt_mode = MPC52xx_GPT_CAN_WDT; 755 on_boot_wdt = of_get_property(ofdev->dev.of_node, 756 "fsl,wdt-on-boot", NULL); 757 if (on_boot_wdt) { 758 dev_info(gpt->dev, "used as watchdog\n"); 759 gpt->wdt_mode |= MPC52xx_GPT_IS_WDT; 760 } else 761 dev_info(gpt->dev, "can function as watchdog\n"); 762 mpc52xx_gpt_wdt_setup(gpt, on_boot_wdt); 763 } 764 765 return 0; 766 } 767 768 static int mpc52xx_gpt_remove(struct platform_device *ofdev) 769 { 770 return -EBUSY; 771 } 772 773 static const struct of_device_id mpc52xx_gpt_match[] = { 774 { .compatible = "fsl,mpc5200-gpt", }, 775 776 /* Depreciated compatible values; don't use for new dts files */ 777 { .compatible = "fsl,mpc5200-gpt-gpio", }, 778 { .compatible = "mpc5200-gpt", }, 779 {} 780 }; 781 782 static struct platform_driver mpc52xx_gpt_driver = { 783 .driver = { 784 .name = "mpc52xx-gpt", 785 .owner = THIS_MODULE, 786 .of_match_table = mpc52xx_gpt_match, 787 }, 788 .probe = mpc52xx_gpt_probe, 789 .remove = mpc52xx_gpt_remove, 790 }; 791 792 static int __init mpc52xx_gpt_init(void) 793 { 794 return platform_driver_register(&mpc52xx_gpt_driver); 795 } 796 797 /* Make sure GPIOs and IRQs get set up before anyone tries to use them */ 798 subsys_initcall(mpc52xx_gpt_init); 799 device_initcall(mpc52xx_gpt_wdt_init); 800