xref: /linux/arch/mips/sibyte/common/sb_tbprof.c (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *
4  * Copyright (C) 2001, 2002, 2003 Broadcom Corporation
5  * Copyright (C) 2007 Ralf Baechle <ralf@linux-mips.org>
6  * Copyright (C) 2007 MIPS Technologies, Inc.
7  *    written by Ralf Baechle <ralf@linux-mips.org>
8  */
9 
10 #undef DEBUG
11 
12 #include <linux/device.h>
13 #include <linux/module.h>
14 #include <linux/kernel.h>
15 #include <linux/types.h>
16 #include <linux/init.h>
17 #include <linux/interrupt.h>
18 #include <linux/sched.h>
19 #include <linux/vmalloc.h>
20 #include <linux/fs.h>
21 #include <linux/errno.h>
22 #include <linux/wait.h>
23 #include <asm/io.h>
24 #include <asm/sibyte/sb1250.h>
25 
26 #ifdef CONFIG_SIBYTE_BCM1x80
27 #include <asm/sibyte/bcm1480_regs.h>
28 #include <asm/sibyte/bcm1480_scd.h>
29 #include <asm/sibyte/bcm1480_int.h>
30 #elif defined(CONFIG_SIBYTE_SB1250) || defined(CONFIG_SIBYTE_BCM112X)
31 #include <asm/sibyte/sb1250_regs.h>
32 #include <asm/sibyte/sb1250_scd.h>
33 #include <asm/sibyte/sb1250_int.h>
34 #else
35 #error invalid SiByte UART configuration
36 #endif
37 
38 #ifdef CONFIG_SIBYTE_BCM1x80
39 #undef K_INT_TRACE_FREEZE
40 #define K_INT_TRACE_FREEZE K_BCM1480_INT_TRACE_FREEZE
41 #undef K_INT_PERF_CNT
42 #define K_INT_PERF_CNT K_BCM1480_INT_PERF_CNT
43 #endif
44 
45 #include <linux/uaccess.h>
46 
47 #define SBPROF_TB_MAJOR 240
48 
49 typedef u64 tb_sample_t[6*256];
50 
51 enum open_status {
52 	SB_CLOSED,
53 	SB_OPENING,
54 	SB_OPEN
55 };
56 
57 struct sbprof_tb {
58 	wait_queue_head_t	tb_sync;
59 	wait_queue_head_t	tb_read;
60 	struct mutex		lock;
61 	enum open_status	open;
62 	tb_sample_t		*sbprof_tbbuf;
63 	int			next_tb_sample;
64 
65 	volatile int		tb_enable;
66 	volatile int		tb_armed;
67 
68 };
69 
70 static struct sbprof_tb sbp;
71 
72 #define MAX_SAMPLE_BYTES (24*1024*1024)
73 #define MAX_TBSAMPLE_BYTES (12*1024*1024)
74 
75 #define MAX_SAMPLES (MAX_SAMPLE_BYTES/sizeof(u_int32_t))
76 #define TB_SAMPLE_SIZE (sizeof(tb_sample_t))
77 #define MAX_TB_SAMPLES (MAX_TBSAMPLE_BYTES/TB_SAMPLE_SIZE)
78 
79 /* ioctls */
80 #define SBPROF_ZBSTART		_IOW('s', 0, int)
81 #define SBPROF_ZBSTOP		_IOW('s', 1, int)
82 #define SBPROF_ZBWAITFULL	_IOW('s', 2, int)
83 
84 /*
85  * Routines for using 40-bit SCD cycle counter
86  *
87  * Client responsible for either handling interrupts or making sure
88  * the cycles counter never saturates, e.g., by doing
89  * zclk_timer_init(0) at least every 2^40 - 1 ZCLKs.
90  */
91 
92 /*
93  * Configures SCD counter 0 to count ZCLKs starting from val;
94  * Configures SCD counters1,2,3 to count nothing.
95  * Must not be called while gathering ZBbus profiles.
96  */
97 
98 #define zclk_timer_init(val) \
99   __asm__ __volatile__ (".set push;" \
100 			".set mips64;" \
101 			"la   $8, 0xb00204c0;" /* SCD perf_cnt_cfg */ \
102 			"sd   %0, 0x10($8);"   /* write val to counter0 */ \
103 			"sd   %1, 0($8);"      /* config counter0 for zclks*/ \
104 			".set pop" \
105 			: /* no outputs */ \
106 						     /* enable, counter0 */ \
107 			: /* inputs */ "r"(val), "r" ((1ULL << 33) | 1ULL) \
108 			: /* modifies */ "$8" )
109 
110 
111 /* Reads SCD counter 0 and puts result in value
112    unsigned long long val; */
113 #define zclk_get(val) \
114   __asm__ __volatile__ (".set push;" \
115 			".set mips64;" \
116 			"la   $8, 0xb00204c0;" /* SCD perf_cnt_cfg */ \
117 			"ld   %0, 0x10($8);"   /* write val to counter0 */ \
118 			".set pop" \
119 			: /* outputs */ "=r"(val) \
120 			: /* inputs */ \
121 			: /* modifies */ "$8" )
122 
123 #define DEVNAME "sb_tbprof"
124 
125 #define TB_FULL (sbp.next_tb_sample == MAX_TB_SAMPLES)
126 
127 /*
128  * Support for ZBbus sampling using the trace buffer
129  *
130  * We use the SCD performance counter interrupt, caused by a Zclk counter
131  * overflow, to trigger the start of tracing.
132  *
133  * We set the trace buffer to sample everything and freeze on
134  * overflow.
135  *
136  * We map the interrupt for trace_buffer_freeze to handle it on CPU 0.
137  *
138  */
139 
140 static u64 tb_period;
141 
arm_tb(void)142 static void arm_tb(void)
143 {
144 	u64 scdperfcnt;
145 	u64 next = (1ULL << 40) - tb_period;
146 	u64 tb_options = M_SCD_TRACE_CFG_FREEZE_FULL;
147 
148 	/*
149 	 * Generate an SCD_PERFCNT interrupt in TB_PERIOD Zclks to
150 	 * trigger start of trace.  XXX vary sampling period
151 	 */
152 	__raw_writeq(0, IOADDR(A_SCD_PERF_CNT_1));
153 	scdperfcnt = __raw_readq(IOADDR(A_SCD_PERF_CNT_CFG));
154 
155 	/*
156 	 * Unfortunately, in Pass 2 we must clear all counters to knock down
157 	 * a previous interrupt request.  This means that bus profiling
158 	 * requires ALL of the SCD perf counters.
159 	 */
160 #ifdef CONFIG_SIBYTE_BCM1x80
161 	__raw_writeq((scdperfcnt & ~M_SPC_CFG_SRC1) |
162 						/* keep counters 0,2,3,4,5,6,7 as is */
163 		     V_SPC_CFG_SRC1(1),		/* counter 1 counts cycles */
164 		     IOADDR(A_BCM1480_SCD_PERF_CNT_CFG0));
165 	__raw_writeq(
166 		     M_SPC_CFG_ENABLE |		/* enable counting */
167 		     M_SPC_CFG_CLEAR |		/* clear all counters */
168 		     V_SPC_CFG_SRC1(1),		/* counter 1 counts cycles */
169 		     IOADDR(A_BCM1480_SCD_PERF_CNT_CFG1));
170 #else
171 	__raw_writeq((scdperfcnt & ~M_SPC_CFG_SRC1) |
172 						/* keep counters 0,2,3 as is */
173 		     M_SPC_CFG_ENABLE |		/* enable counting */
174 		     M_SPC_CFG_CLEAR |		/* clear all counters */
175 		     V_SPC_CFG_SRC1(1),		/* counter 1 counts cycles */
176 		     IOADDR(A_SCD_PERF_CNT_CFG));
177 #endif
178 	__raw_writeq(next, IOADDR(A_SCD_PERF_CNT_1));
179 	/* Reset the trace buffer */
180 	__raw_writeq(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
181 #if 0 && defined(M_SCD_TRACE_CFG_FORCECNT)
182 	/* XXXKW may want to expose control to the data-collector */
183 	tb_options |= M_SCD_TRACE_CFG_FORCECNT;
184 #endif
185 	__raw_writeq(tb_options, IOADDR(A_SCD_TRACE_CFG));
186 	sbp.tb_armed = 1;
187 }
188 
sbprof_tb_intr(int irq,void * dev_id)189 static irqreturn_t sbprof_tb_intr(int irq, void *dev_id)
190 {
191 	int i;
192 
193 	pr_debug(DEVNAME ": tb_intr\n");
194 
195 	if (sbp.next_tb_sample < MAX_TB_SAMPLES) {
196 		/* XXX should use XKPHYS to make writes bypass L2 */
197 		u64 *p = sbp.sbprof_tbbuf[sbp.next_tb_sample++];
198 		/* Read out trace */
199 		__raw_writeq(M_SCD_TRACE_CFG_START_READ,
200 			     IOADDR(A_SCD_TRACE_CFG));
201 		__asm__ __volatile__ ("sync" : : : "memory");
202 		/* Loop runs backwards because bundles are read out in reverse order */
203 		for (i = 256 * 6; i > 0; i -= 6) {
204 			/* Subscripts decrease to put bundle in the order */
205 			/*   t0 lo, t0 hi, t1 lo, t1 hi, t2 lo, t2 hi */
206 			p[i - 1] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
207 			/* read t2 hi */
208 			p[i - 2] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
209 			/* read t2 lo */
210 			p[i - 3] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
211 			/* read t1 hi */
212 			p[i - 4] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
213 			/* read t1 lo */
214 			p[i - 5] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
215 			/* read t0 hi */
216 			p[i - 6] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
217 			/* read t0 lo */
218 		}
219 		if (!sbp.tb_enable) {
220 			pr_debug(DEVNAME ": tb_intr shutdown\n");
221 			__raw_writeq(M_SCD_TRACE_CFG_RESET,
222 				     IOADDR(A_SCD_TRACE_CFG));
223 			sbp.tb_armed = 0;
224 			wake_up_interruptible(&sbp.tb_sync);
225 		} else {
226 			/* knock down current interrupt and get another one later */
227 			arm_tb();
228 		}
229 	} else {
230 		/* No more trace buffer samples */
231 		pr_debug(DEVNAME ": tb_intr full\n");
232 		__raw_writeq(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
233 		sbp.tb_armed = 0;
234 		if (!sbp.tb_enable)
235 			wake_up_interruptible(&sbp.tb_sync);
236 		wake_up_interruptible(&sbp.tb_read);
237 	}
238 	return IRQ_HANDLED;
239 }
240 
sbprof_pc_intr(int irq,void * dev_id)241 static irqreturn_t sbprof_pc_intr(int irq, void *dev_id)
242 {
243 	printk(DEVNAME ": unexpected pc_intr");
244 	return IRQ_NONE;
245 }
246 
247 /*
248  * Requires: Already called zclk_timer_init with a value that won't
249  *	     saturate 40 bits.	No subsequent use of SCD performance counters
250  *	     or trace buffer.
251  */
252 
sbprof_zbprof_start(struct file * filp)253 static int sbprof_zbprof_start(struct file *filp)
254 {
255 	u64 scdperfcnt;
256 	int err;
257 
258 	if (xchg(&sbp.tb_enable, 1))
259 		return -EBUSY;
260 
261 	pr_debug(DEVNAME ": starting\n");
262 
263 	sbp.next_tb_sample = 0;
264 	filp->f_pos = 0;
265 
266 	err = request_irq(K_INT_TRACE_FREEZE, sbprof_tb_intr, 0,
267 			  DEVNAME " trace freeze", &sbp);
268 	if (err)
269 		return -EBUSY;
270 
271 	/* Make sure there isn't a perf-cnt interrupt waiting */
272 	scdperfcnt = __raw_readq(IOADDR(A_SCD_PERF_CNT_CFG));
273 	/* Disable and clear counters, override SRC_1 */
274 	__raw_writeq((scdperfcnt & ~(M_SPC_CFG_SRC1 | M_SPC_CFG_ENABLE)) |
275 		     M_SPC_CFG_ENABLE | M_SPC_CFG_CLEAR | V_SPC_CFG_SRC1(1),
276 		     IOADDR(A_SCD_PERF_CNT_CFG));
277 
278 	/*
279 	 * We grab this interrupt to prevent others from trying to use
280 	 * it, even though we don't want to service the interrupts
281 	 * (they only feed into the trace-on-interrupt mechanism)
282 	 */
283 	if (request_irq(K_INT_PERF_CNT, sbprof_pc_intr, 0, DEVNAME " scd perfcnt", &sbp)) {
284 		free_irq(K_INT_TRACE_FREEZE, &sbp);
285 		return -EBUSY;
286 	}
287 
288 	/*
289 	 * I need the core to mask these, but the interrupt mapper to
290 	 *  pass them through.	I am exploiting my knowledge that
291 	 *  cp0_status masks out IP[5]. krw
292 	 */
293 #ifdef CONFIG_SIBYTE_BCM1x80
294 	__raw_writeq(K_BCM1480_INT_MAP_I3,
295 		     IOADDR(A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_INTERRUPT_MAP_BASE_L) +
296 			    ((K_BCM1480_INT_PERF_CNT & 0x3f) << 3)));
297 #else
298 	__raw_writeq(K_INT_MAP_I3,
299 		     IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
300 			    (K_INT_PERF_CNT << 3)));
301 #endif
302 
303 	/* Initialize address traps */
304 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_0));
305 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_1));
306 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_2));
307 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_3));
308 
309 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_0));
310 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_1));
311 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_2));
312 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_3));
313 
314 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_0));
315 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_1));
316 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_2));
317 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_3));
318 
319 	/* Initialize Trace Event 0-7 */
320 	/*				when interrupt	*/
321 	__raw_writeq(M_SCD_TREVT_INTERRUPT, IOADDR(A_SCD_TRACE_EVENT_0));
322 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_1));
323 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_2));
324 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_3));
325 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_4));
326 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_5));
327 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_6));
328 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_7));
329 
330 	/* Initialize Trace Sequence 0-7 */
331 	/*				     Start on event 0 (interrupt) */
332 	__raw_writeq(V_SCD_TRSEQ_FUNC_START | 0x0fff,
333 		     IOADDR(A_SCD_TRACE_SEQUENCE_0));
334 	/*			  dsamp when d used | asamp when a used */
335 	__raw_writeq(M_SCD_TRSEQ_ASAMPLE | M_SCD_TRSEQ_DSAMPLE |
336 		     K_SCD_TRSEQ_TRIGGER_ALL,
337 		     IOADDR(A_SCD_TRACE_SEQUENCE_1));
338 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_2));
339 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_3));
340 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_4));
341 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_5));
342 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_6));
343 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_7));
344 
345 	/* Now indicate the PERF_CNT interrupt as a trace-relevant interrupt */
346 #ifdef CONFIG_SIBYTE_BCM1x80
347 	__raw_writeq(1ULL << (K_BCM1480_INT_PERF_CNT & 0x3f),
348 		     IOADDR(A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_INTERRUPT_TRACE_L)));
349 #else
350 	__raw_writeq(1ULL << K_INT_PERF_CNT,
351 		     IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_TRACE)));
352 #endif
353 	arm_tb();
354 
355 	pr_debug(DEVNAME ": done starting\n");
356 
357 	return 0;
358 }
359 
sbprof_zbprof_stop(void)360 static int sbprof_zbprof_stop(void)
361 {
362 	int err = 0;
363 
364 	pr_debug(DEVNAME ": stopping\n");
365 
366 	if (sbp.tb_enable) {
367 		/*
368 		 * XXXKW there is a window here where the intr handler may run,
369 		 * see the disable, and do the wake_up before this sleep
370 		 * happens.
371 		 */
372 		pr_debug(DEVNAME ": wait for disarm\n");
373 		err = wait_event_interruptible(sbp.tb_sync, !sbp.tb_armed);
374 		pr_debug(DEVNAME ": disarm complete, stat %d\n", err);
375 
376 		if (err)
377 			return err;
378 
379 		sbp.tb_enable = 0;
380 		free_irq(K_INT_TRACE_FREEZE, &sbp);
381 		free_irq(K_INT_PERF_CNT, &sbp);
382 	}
383 
384 	pr_debug(DEVNAME ": done stopping\n");
385 
386 	return err;
387 }
388 
sbprof_tb_open(struct inode * inode,struct file * filp)389 static int sbprof_tb_open(struct inode *inode, struct file *filp)
390 {
391 	int minor;
392 
393 	minor = iminor(inode);
394 	if (minor != 0)
395 		return -ENODEV;
396 
397 	if (xchg(&sbp.open, SB_OPENING) != SB_CLOSED)
398 		return -EBUSY;
399 
400 	memset(&sbp, 0, sizeof(struct sbprof_tb));
401 	sbp.sbprof_tbbuf = vzalloc(MAX_TBSAMPLE_BYTES);
402 	if (!sbp.sbprof_tbbuf) {
403 		sbp.open = SB_CLOSED;
404 		wmb();
405 		return -ENOMEM;
406 	}
407 
408 	init_waitqueue_head(&sbp.tb_sync);
409 	init_waitqueue_head(&sbp.tb_read);
410 	mutex_init(&sbp.lock);
411 
412 	sbp.open = SB_OPEN;
413 	wmb();
414 
415 	return 0;
416 }
417 
sbprof_tb_release(struct inode * inode,struct file * filp)418 static int sbprof_tb_release(struct inode *inode, struct file *filp)
419 {
420 	int minor;
421 
422 	minor = iminor(inode);
423 	if (minor != 0 || sbp.open != SB_CLOSED)
424 		return -ENODEV;
425 
426 	mutex_lock(&sbp.lock);
427 
428 	if (sbp.tb_armed || sbp.tb_enable)
429 		sbprof_zbprof_stop();
430 
431 	vfree(sbp.sbprof_tbbuf);
432 	sbp.open = SB_CLOSED;
433 	wmb();
434 
435 	mutex_unlock(&sbp.lock);
436 
437 	return 0;
438 }
439 
sbprof_tb_read(struct file * filp,char __user * buf,size_t size,loff_t * offp)440 static ssize_t sbprof_tb_read(struct file *filp, char __user *buf,
441 			      size_t size, loff_t *offp)
442 {
443 	int cur_sample, sample_off, cur_count, sample_left;
444 	char *src;
445 	int   count   =	 0;
446 	char __user *dest    =	 buf;
447 	long  cur_off = *offp;
448 
449 	if (!access_ok(buf, size))
450 		return -EFAULT;
451 
452 	mutex_lock(&sbp.lock);
453 
454 	count = 0;
455 	cur_sample = cur_off / TB_SAMPLE_SIZE;
456 	sample_off = cur_off % TB_SAMPLE_SIZE;
457 	sample_left = TB_SAMPLE_SIZE - sample_off;
458 
459 	while (size && (cur_sample < sbp.next_tb_sample)) {
460 		int err;
461 
462 		cur_count = size < sample_left ? size : sample_left;
463 		src = (char *)(((long)sbp.sbprof_tbbuf[cur_sample])+sample_off);
464 		err = __copy_to_user(dest, src, cur_count);
465 		if (err) {
466 			*offp = cur_off + cur_count - err;
467 			mutex_unlock(&sbp.lock);
468 			return err;
469 		}
470 		pr_debug(DEVNAME ": read from sample %d, %d bytes\n",
471 			 cur_sample, cur_count);
472 		size -= cur_count;
473 		sample_left -= cur_count;
474 		if (!sample_left) {
475 			cur_sample++;
476 			sample_off = 0;
477 			sample_left = TB_SAMPLE_SIZE;
478 		} else {
479 			sample_off += cur_count;
480 		}
481 		cur_off += cur_count;
482 		dest += cur_count;
483 		count += cur_count;
484 	}
485 	*offp = cur_off;
486 	mutex_unlock(&sbp.lock);
487 
488 	return count;
489 }
490 
sbprof_tb_ioctl(struct file * filp,unsigned int command,unsigned long arg)491 static long sbprof_tb_ioctl(struct file *filp,
492 			    unsigned int command,
493 			    unsigned long arg)
494 {
495 	int err = 0;
496 
497 	switch (command) {
498 	case SBPROF_ZBSTART:
499 		mutex_lock(&sbp.lock);
500 		err = sbprof_zbprof_start(filp);
501 		mutex_unlock(&sbp.lock);
502 		break;
503 
504 	case SBPROF_ZBSTOP:
505 		mutex_lock(&sbp.lock);
506 		err = sbprof_zbprof_stop();
507 		mutex_unlock(&sbp.lock);
508 		break;
509 
510 	case SBPROF_ZBWAITFULL: {
511 		err = wait_event_interruptible(sbp.tb_read, TB_FULL);
512 		if (err)
513 			break;
514 
515 		err = put_user(TB_FULL, (int __user *) arg);
516 		break;
517 	}
518 
519 	default:
520 		err = -EINVAL;
521 		break;
522 	}
523 
524 	return err;
525 }
526 
527 static const struct file_operations sbprof_tb_fops = {
528 	.owner		= THIS_MODULE,
529 	.open		= sbprof_tb_open,
530 	.release	= sbprof_tb_release,
531 	.read		= sbprof_tb_read,
532 	.unlocked_ioctl = sbprof_tb_ioctl,
533 	.compat_ioctl	= sbprof_tb_ioctl,
534 	.mmap		= NULL,
535 	.llseek		= default_llseek,
536 };
537 
538 static const struct class tb_class = {
539 	.name = "sb_tracebuffer",
540 };
541 static struct device *tb_dev;
542 
sbprof_tb_init(void)543 static int __init sbprof_tb_init(void)
544 {
545 	struct device *dev;
546 	int err;
547 
548 	if (register_chrdev(SBPROF_TB_MAJOR, DEVNAME, &sbprof_tb_fops)) {
549 		printk(KERN_WARNING DEVNAME ": initialization failed (dev %d)\n",
550 		       SBPROF_TB_MAJOR);
551 		return -EIO;
552 	}
553 
554 	err = class_register(&tb_class);
555 	if (err)
556 		goto out_chrdev;
557 
558 	dev = device_create(&tb_class, NULL, MKDEV(SBPROF_TB_MAJOR, 0), NULL, "tb");
559 	if (IS_ERR(dev)) {
560 		err = PTR_ERR(dev);
561 		goto out_class;
562 	}
563 	tb_dev = dev;
564 
565 	sbp.open = SB_CLOSED;
566 	wmb();
567 	tb_period = zbbus_mhz * 10000LL;
568 	pr_info(DEVNAME ": initialized - tb_period = %lld\n",
569 		(long long) tb_period);
570 	return 0;
571 
572 out_class:
573 	class_unregister(&tb_class);
574 out_chrdev:
575 	unregister_chrdev(SBPROF_TB_MAJOR, DEVNAME);
576 
577 	return err;
578 }
579 
sbprof_tb_cleanup(void)580 static void __exit sbprof_tb_cleanup(void)
581 {
582 	device_destroy(&tb_class, MKDEV(SBPROF_TB_MAJOR, 0));
583 	unregister_chrdev(SBPROF_TB_MAJOR, DEVNAME);
584 	class_unregister(&tb_class);
585 }
586 
587 module_init(sbprof_tb_init);
588 module_exit(sbprof_tb_cleanup);
589 
590 MODULE_ALIAS_CHARDEV_MAJOR(SBPROF_TB_MAJOR);
591 MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
592 MODULE_DESCRIPTION("Support for ZBbus profiling");
593 MODULE_LICENSE("GPL");
594