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
mpc52xx_gpt_irq_unmask(struct irq_data * d)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
mpc52xx_gpt_irq_mask(struct irq_data * d)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
mpc52xx_gpt_irq_ack(struct irq_data * d)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
mpc52xx_gpt_irq_set_type(struct irq_data * d,unsigned int flow_type)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
mpc52xx_gpt_irq_cascade(unsigned int virq,struct irq_desc * desc)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
mpc52xx_gpt_irq_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw)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
mpc52xx_gpt_irq_xlate(struct irq_domain * h,struct device_node * ct,const u32 * intspec,unsigned int intsize,irq_hw_number_t * out_hwirq,unsigned int * out_flags)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
mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv * gpt,struct device_node * node)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)
gc_to_mpc52xx_gpt(struct gpio_chip * gc)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
mpc52xx_gpt_gpio_get(struct gpio_chip * gc,unsigned int gpio)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
mpc52xx_gpt_gpio_set(struct gpio_chip * gc,unsigned int gpio,int v)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
mpc52xx_gpt_gpio_dir_in(struct gpio_chip * gc,unsigned int gpio)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
mpc52xx_gpt_gpio_dir_out(struct gpio_chip * gc,unsigned int gpio,int val)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
mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv * gpt,struct device_node * node)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
mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv * p,struct device_node * np)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 */
mpc52xx_gpt_from_irq(int irq)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
mpc52xx_gpt_do_start(struct mpc52xx_gpt_priv * gpt,u64 period,int continuous,int as_wdt)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 */
mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv * gpt,u64 period,int continuous)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 */
mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv * gpt)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 */
mpc52xx_gpt_timer_period(struct mpc52xx_gpt_priv * gpt)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 whether 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 */
mpc52xx_gpt_wdt_ping(struct mpc52xx_gpt_priv * gpt_wdt)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 */
mpc52xx_wdt_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)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
mpc52xx_wdt_ioctl(struct file * file,unsigned int cmd,unsigned long arg)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
mpc52xx_wdt_open(struct inode * inode,struct file * file)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
mpc52xx_wdt_release(struct inode * inode,struct file * file)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
mpc52xx_gpt_wdt_init(void)672 static int 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
mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv * gpt,const u32 * period)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
mpc52xx_gpt_wdt_init(void)707 static int mpc52xx_gpt_wdt_init(void)
708 {
709 return 0;
710 }
711
mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv * gpt,const u32 * period)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 */
mpc52xx_gpt_probe(struct platform_device * ofdev)723 static int 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
mpc52xx_gpt_remove(struct platform_device * ofdev)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
mpc52xx_gpt_init(void)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