1 /*
2  * This program is free software; you can redistribute it and/or
3  * modify it under the terms of the GNU General Public License
4  * as published by the Free Software Foundation; either version 2
5  * of the License, or (at your option) any later version.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * along with this program; if not, write to the Free Software
14  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
15  *
16  * Copyright (C) 2001, 2002, 2003 Broadcom Corporation
17  * Copyright (C) 2007 Ralf Baechle <ralf@linux-mips.org>
18  * Copyright (C) 2007 MIPS Technologies, Inc.
19  *    written by Ralf Baechle <ralf@linux-mips.org>
20  */
21 
22 #undef DEBUG
23 
24 #include <linux/device.h>
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/types.h>
28 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/slab.h>
31 #include <linux/smp_lock.h>
32 #include <linux/vmalloc.h>
33 #include <linux/fs.h>
34 #include <linux/errno.h>
35 #include <linux/wait.h>
36 #include <asm/io.h>
37 #include <asm/sibyte/sb1250.h>
38 
39 #if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
40 #include <asm/sibyte/bcm1480_regs.h>
41 #include <asm/sibyte/bcm1480_scd.h>
42 #include <asm/sibyte/bcm1480_int.h>
43 #elif defined(CONFIG_SIBYTE_SB1250) || defined(CONFIG_SIBYTE_BCM112X)
44 #include <asm/sibyte/sb1250_regs.h>
45 #include <asm/sibyte/sb1250_scd.h>
46 #include <asm/sibyte/sb1250_int.h>
47 #else
48 #error invalid SiByte UART configuation
49 #endif
50 
51 #if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
52 #undef K_INT_TRACE_FREEZE
53 #define K_INT_TRACE_FREEZE K_BCM1480_INT_TRACE_FREEZE
54 #undef K_INT_PERF_CNT
55 #define K_INT_PERF_CNT K_BCM1480_INT_PERF_CNT
56 #endif
57 
58 #include <asm/system.h>
59 #include <asm/uaccess.h>
60 
61 #define SBPROF_TB_MAJOR 240
62 
63 typedef u64 tb_sample_t[6*256];
64 
65 enum open_status {
66 	SB_CLOSED,
67 	SB_OPENING,
68 	SB_OPEN
69 };
70 
71 struct sbprof_tb {
72 	wait_queue_head_t	tb_sync;
73 	wait_queue_head_t	tb_read;
74 	struct mutex		lock;
75 	enum open_status	open;
76 	tb_sample_t		*sbprof_tbbuf;
77 	int			next_tb_sample;
78 
79 	volatile int		tb_enable;
80 	volatile int		tb_armed;
81 
82 };
83 
84 static struct sbprof_tb sbp;
85 
86 #define MAX_SAMPLE_BYTES (24*1024*1024)
87 #define MAX_TBSAMPLE_BYTES (12*1024*1024)
88 
89 #define MAX_SAMPLES (MAX_SAMPLE_BYTES/sizeof(u_int32_t))
90 #define TB_SAMPLE_SIZE (sizeof(tb_sample_t))
91 #define MAX_TB_SAMPLES (MAX_TBSAMPLE_BYTES/TB_SAMPLE_SIZE)
92 
93 /* ioctls */
94 #define SBPROF_ZBSTART		_IOW('s', 0, int)
95 #define SBPROF_ZBSTOP		_IOW('s', 1, int)
96 #define SBPROF_ZBWAITFULL	_IOW('s', 2, int)
97 
98 /*
99  * Routines for using 40-bit SCD cycle counter
100  *
101  * Client responsible for either handling interrupts or making sure
102  * the cycles counter never saturates, e.g., by doing
103  * zclk_timer_init(0) at least every 2^40 - 1 ZCLKs.
104  */
105 
106 /*
107  * Configures SCD counter 0 to count ZCLKs starting from val;
108  * Configures SCD counters1,2,3 to count nothing.
109  * Must not be called while gathering ZBbus profiles.
110  */
111 
112 #define zclk_timer_init(val) \
113   __asm__ __volatile__ (".set push;" \
114 			".set mips64;" \
115 			"la   $8, 0xb00204c0;" /* SCD perf_cnt_cfg */ \
116 			"sd   %0, 0x10($8);"   /* write val to counter0 */ \
117 			"sd   %1, 0($8);"      /* config counter0 for zclks*/ \
118 			".set pop" \
119 			: /* no outputs */ \
120 						     /* enable, counter0 */ \
121 			: /* inputs */ "r"(val), "r" ((1ULL << 33) | 1ULL) \
122 			: /* modifies */ "$8" )
123 
124 
125 /* Reads SCD counter 0 and puts result in value
126    unsigned long long val; */
127 #define zclk_get(val) \
128   __asm__ __volatile__ (".set push;" \
129 			".set mips64;" \
130 			"la   $8, 0xb00204c0;" /* SCD perf_cnt_cfg */ \
131 			"ld   %0, 0x10($8);"   /* write val to counter0 */ \
132 			".set pop" \
133 			: /* outputs */ "=r"(val) \
134 			: /* inputs */ \
135 			: /* modifies */ "$8" )
136 
137 #define DEVNAME "sb_tbprof"
138 
139 #define TB_FULL (sbp.next_tb_sample == MAX_TB_SAMPLES)
140 
141 /*
142  * Support for ZBbus sampling using the trace buffer
143  *
144  * We use the SCD performance counter interrupt, caused by a Zclk counter
145  * overflow, to trigger the start of tracing.
146  *
147  * We set the trace buffer to sample everything and freeze on
148  * overflow.
149  *
150  * We map the interrupt for trace_buffer_freeze to handle it on CPU 0.
151  *
152  */
153 
154 static u64 tb_period;
155 
156 static void arm_tb(void)
157 {
158         u64 scdperfcnt;
159 	u64 next = (1ULL << 40) - tb_period;
160 	u64 tb_options = M_SCD_TRACE_CFG_FREEZE_FULL;
161 
162 	/*
163 	 * Generate an SCD_PERFCNT interrupt in TB_PERIOD Zclks to
164 	 * trigger start of trace.  XXX vary sampling period
165 	 */
166 	__raw_writeq(0, IOADDR(A_SCD_PERF_CNT_1));
167 	scdperfcnt = __raw_readq(IOADDR(A_SCD_PERF_CNT_CFG));
168 
169 	/*
170 	 * Unfortunately, in Pass 2 we must clear all counters to knock down
171 	 * a previous interrupt request.  This means that bus profiling
172 	 * requires ALL of the SCD perf counters.
173 	 */
174 #if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
175 	__raw_writeq((scdperfcnt & ~M_SPC_CFG_SRC1) |
176 						/* keep counters 0,2,3,4,5,6,7 as is */
177 		     V_SPC_CFG_SRC1(1),		/* counter 1 counts cycles */
178 		     IOADDR(A_BCM1480_SCD_PERF_CNT_CFG0));
179 	__raw_writeq(
180 		     M_SPC_CFG_ENABLE |		/* enable counting */
181 		     M_SPC_CFG_CLEAR |		/* clear all counters */
182 		     V_SPC_CFG_SRC1(1),		/* counter 1 counts cycles */
183 		     IOADDR(A_BCM1480_SCD_PERF_CNT_CFG1));
184 #else
185 	__raw_writeq((scdperfcnt & ~M_SPC_CFG_SRC1) |
186 						/* keep counters 0,2,3 as is */
187 		     M_SPC_CFG_ENABLE |		/* enable counting */
188 		     M_SPC_CFG_CLEAR |		/* clear all counters */
189 		     V_SPC_CFG_SRC1(1),		/* counter 1 counts cycles */
190 		     IOADDR(A_SCD_PERF_CNT_CFG));
191 #endif
192 	__raw_writeq(next, IOADDR(A_SCD_PERF_CNT_1));
193 	/* Reset the trace buffer */
194 	__raw_writeq(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
195 #if 0 && defined(M_SCD_TRACE_CFG_FORCECNT)
196 	/* XXXKW may want to expose control to the data-collector */
197 	tb_options |= M_SCD_TRACE_CFG_FORCECNT;
198 #endif
199 	__raw_writeq(tb_options, IOADDR(A_SCD_TRACE_CFG));
200 	sbp.tb_armed = 1;
201 }
202 
203 static irqreturn_t sbprof_tb_intr(int irq, void *dev_id)
204 {
205 	int i;
206 
207 	pr_debug(DEVNAME ": tb_intr\n");
208 
209 	if (sbp.next_tb_sample < MAX_TB_SAMPLES) {
210 		/* XXX should use XKPHYS to make writes bypass L2 */
211 		u64 *p = sbp.sbprof_tbbuf[sbp.next_tb_sample++];
212 		/* Read out trace */
213 		__raw_writeq(M_SCD_TRACE_CFG_START_READ,
214 			     IOADDR(A_SCD_TRACE_CFG));
215 		__asm__ __volatile__ ("sync" : : : "memory");
216 		/* Loop runs backwards because bundles are read out in reverse order */
217 		for (i = 256 * 6; i > 0; i -= 6) {
218 			/* Subscripts decrease to put bundle in the order */
219 			/*   t0 lo, t0 hi, t1 lo, t1 hi, t2 lo, t2 hi */
220 			p[i - 1] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
221 			/* read t2 hi */
222 			p[i - 2] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
223 			/* read t2 lo */
224 			p[i - 3] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
225 			/* read t1 hi */
226 			p[i - 4] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
227 			/* read t1 lo */
228 			p[i - 5] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
229 			/* read t0 hi */
230 			p[i - 6] = __raw_readq(IOADDR(A_SCD_TRACE_READ));
231 			/* read t0 lo */
232 		}
233 		if (!sbp.tb_enable) {
234 			pr_debug(DEVNAME ": tb_intr shutdown\n");
235 			__raw_writeq(M_SCD_TRACE_CFG_RESET,
236 				     IOADDR(A_SCD_TRACE_CFG));
237 			sbp.tb_armed = 0;
238 			wake_up_interruptible(&sbp.tb_sync);
239 		} else {
240 			/* knock down current interrupt and get another one later */
241 			arm_tb();
242 		}
243 	} else {
244 		/* No more trace buffer samples */
245 		pr_debug(DEVNAME ": tb_intr full\n");
246 		__raw_writeq(M_SCD_TRACE_CFG_RESET, IOADDR(A_SCD_TRACE_CFG));
247 		sbp.tb_armed = 0;
248 		if (!sbp.tb_enable)
249 			wake_up_interruptible(&sbp.tb_sync);
250 		wake_up_interruptible(&sbp.tb_read);
251 	}
252 	return IRQ_HANDLED;
253 }
254 
255 static irqreturn_t sbprof_pc_intr(int irq, void *dev_id)
256 {
257 	printk(DEVNAME ": unexpected pc_intr");
258 	return IRQ_NONE;
259 }
260 
261 /*
262  * Requires: Already called zclk_timer_init with a value that won't
263  *           saturate 40 bits.  No subsequent use of SCD performance counters
264  *           or trace buffer.
265  */
266 
267 static int sbprof_zbprof_start(struct file *filp)
268 {
269 	u64 scdperfcnt;
270 	int err;
271 
272 	if (xchg(&sbp.tb_enable, 1))
273 		return -EBUSY;
274 
275 	pr_debug(DEVNAME ": starting\n");
276 
277 	sbp.next_tb_sample = 0;
278 	filp->f_pos = 0;
279 
280 	err = request_irq(K_INT_TRACE_FREEZE, sbprof_tb_intr, 0,
281 			  DEVNAME " trace freeze", &sbp);
282 	if (err)
283 		return -EBUSY;
284 
285 	/* Make sure there isn't a perf-cnt interrupt waiting */
286 	scdperfcnt = __raw_readq(IOADDR(A_SCD_PERF_CNT_CFG));
287 	/* Disable and clear counters, override SRC_1 */
288 	__raw_writeq((scdperfcnt & ~(M_SPC_CFG_SRC1 | M_SPC_CFG_ENABLE)) |
289 		     M_SPC_CFG_ENABLE | M_SPC_CFG_CLEAR | V_SPC_CFG_SRC1(1),
290 		     IOADDR(A_SCD_PERF_CNT_CFG));
291 
292 	/*
293 	 * We grab this interrupt to prevent others from trying to use
294          * it, even though we don't want to service the interrupts
295          * (they only feed into the trace-on-interrupt mechanism)
296 	 */
297 	if (request_irq(K_INT_PERF_CNT, sbprof_pc_intr, 0, DEVNAME " scd perfcnt", &sbp)) {
298 		free_irq(K_INT_TRACE_FREEZE, &sbp);
299 		return -EBUSY;
300 	}
301 
302 	/*
303 	 * I need the core to mask these, but the interrupt mapper to
304 	 *  pass them through.  I am exploiting my knowledge that
305 	 *  cp0_status masks out IP[5]. krw
306 	 */
307 #if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
308 	__raw_writeq(K_BCM1480_INT_MAP_I3,
309 		     IOADDR(A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_INTERRUPT_MAP_BASE_L) +
310 			    ((K_BCM1480_INT_PERF_CNT & 0x3f) << 3)));
311 #else
312 	__raw_writeq(K_INT_MAP_I3,
313 		     IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
314 			    (K_INT_PERF_CNT << 3)));
315 #endif
316 
317 	/* Initialize address traps */
318 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_0));
319 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_1));
320 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_2));
321 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_UP_3));
322 
323 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_0));
324 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_1));
325 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_2));
326 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_DOWN_3));
327 
328 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_0));
329 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_1));
330 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_2));
331 	__raw_writeq(0, IOADDR(A_ADDR_TRAP_CFG_3));
332 
333 	/* Initialize Trace Event 0-7 */
334 	/*				when interrupt  */
335 	__raw_writeq(M_SCD_TREVT_INTERRUPT, IOADDR(A_SCD_TRACE_EVENT_0));
336 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_1));
337 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_2));
338 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_3));
339 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_4));
340 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_5));
341 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_6));
342 	__raw_writeq(0, IOADDR(A_SCD_TRACE_EVENT_7));
343 
344 	/* Initialize Trace Sequence 0-7 */
345 	/*				     Start on event 0 (interrupt) */
346 	__raw_writeq(V_SCD_TRSEQ_FUNC_START | 0x0fff,
347 		     IOADDR(A_SCD_TRACE_SEQUENCE_0));
348 	/*			  dsamp when d used | asamp when a used */
349 	__raw_writeq(M_SCD_TRSEQ_ASAMPLE | M_SCD_TRSEQ_DSAMPLE |
350 		     K_SCD_TRSEQ_TRIGGER_ALL,
351 		     IOADDR(A_SCD_TRACE_SEQUENCE_1));
352 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_2));
353 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_3));
354 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_4));
355 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_5));
356 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_6));
357 	__raw_writeq(0, IOADDR(A_SCD_TRACE_SEQUENCE_7));
358 
359 	/* Now indicate the PERF_CNT interrupt as a trace-relevant interrupt */
360 #if defined(CONFIG_SIBYTE_BCM1x55) || defined(CONFIG_SIBYTE_BCM1x80)
361 	__raw_writeq(1ULL << (K_BCM1480_INT_PERF_CNT & 0x3f),
362 		     IOADDR(A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_INTERRUPT_TRACE_L)));
363 #else
364 	__raw_writeq(1ULL << K_INT_PERF_CNT,
365 		     IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_TRACE)));
366 #endif
367 	arm_tb();
368 
369 	pr_debug(DEVNAME ": done starting\n");
370 
371 	return 0;
372 }
373 
374 static int sbprof_zbprof_stop(void)
375 {
376 	int err = 0;
377 
378 	pr_debug(DEVNAME ": stopping\n");
379 
380 	if (sbp.tb_enable) {
381 		/*
382 		 * XXXKW there is a window here where the intr handler may run,
383 		 * see the disable, and do the wake_up before this sleep
384 		 * happens.
385 		 */
386 		pr_debug(DEVNAME ": wait for disarm\n");
387 		err = wait_event_interruptible(sbp.tb_sync, !sbp.tb_armed);
388 		pr_debug(DEVNAME ": disarm complete, stat %d\n", err);
389 
390 		if (err)
391 			return err;
392 
393 		sbp.tb_enable = 0;
394 		free_irq(K_INT_TRACE_FREEZE, &sbp);
395 		free_irq(K_INT_PERF_CNT, &sbp);
396 	}
397 
398 	pr_debug(DEVNAME ": done stopping\n");
399 
400 	return err;
401 }
402 
403 static int sbprof_tb_open(struct inode *inode, struct file *filp)
404 {
405 	int minor;
406 
407 	minor = iminor(inode);
408 	if (minor != 0)
409 		return -ENODEV;
410 
411 	if (xchg(&sbp.open, SB_OPENING) != SB_CLOSED)
412 		return -EBUSY;
413 
414 	memset(&sbp, 0, sizeof(struct sbprof_tb));
415 	sbp.sbprof_tbbuf = vmalloc(MAX_TBSAMPLE_BYTES);
416 	if (!sbp.sbprof_tbbuf) {
417 		sbp.open = SB_CLOSED;
418 		wmb();
419 		return -ENOMEM;
420 	}
421 
422 	memset(sbp.sbprof_tbbuf, 0, MAX_TBSAMPLE_BYTES);
423 	init_waitqueue_head(&sbp.tb_sync);
424 	init_waitqueue_head(&sbp.tb_read);
425 	mutex_init(&sbp.lock);
426 
427 	sbp.open = SB_OPEN;
428 	wmb();
429 
430 	return 0;
431 }
432 
433 static int sbprof_tb_release(struct inode *inode, struct file *filp)
434 {
435 	int minor;
436 
437 	minor = iminor(inode);
438 	if (minor != 0 || sbp.open != SB_CLOSED)
439 		return -ENODEV;
440 
441 	mutex_lock(&sbp.lock);
442 
443 	if (sbp.tb_armed || sbp.tb_enable)
444 		sbprof_zbprof_stop();
445 
446 	vfree(sbp.sbprof_tbbuf);
447 	sbp.open = SB_CLOSED;
448 	wmb();
449 
450 	mutex_unlock(&sbp.lock);
451 
452 	return 0;
453 }
454 
455 static ssize_t sbprof_tb_read(struct file *filp, char *buf,
456 			      size_t size, loff_t *offp)
457 {
458 	int cur_sample, sample_off, cur_count, sample_left;
459 	char *src;
460 	int   count   =	 0;
461 	char *dest    =	 buf;
462 	long  cur_off = *offp;
463 
464 	if (!access_ok(VERIFY_WRITE, buf, size))
465 		return -EFAULT;
466 
467 	mutex_lock(&sbp.lock);
468 
469 	count = 0;
470 	cur_sample = cur_off / TB_SAMPLE_SIZE;
471 	sample_off = cur_off % TB_SAMPLE_SIZE;
472 	sample_left = TB_SAMPLE_SIZE - sample_off;
473 
474 	while (size && (cur_sample < sbp.next_tb_sample)) {
475 		int err;
476 
477 		cur_count = size < sample_left ? size : sample_left;
478 		src = (char *)(((long)sbp.sbprof_tbbuf[cur_sample])+sample_off);
479 		err = __copy_to_user(dest, src, cur_count);
480 		if (err) {
481 			*offp = cur_off + cur_count - err;
482 			mutex_unlock(&sbp.lock);
483 			return err;
484 		}
485 		pr_debug(DEVNAME ": read from sample %d, %d bytes\n",
486 		         cur_sample, cur_count);
487 		size -= cur_count;
488 		sample_left -= cur_count;
489 		if (!sample_left) {
490 			cur_sample++;
491 			sample_off = 0;
492 			sample_left = TB_SAMPLE_SIZE;
493 		} else {
494 			sample_off += cur_count;
495 		}
496 		cur_off += cur_count;
497 		dest += cur_count;
498 		count += cur_count;
499 	}
500 	*offp = cur_off;
501 	mutex_unlock(&sbp.lock);
502 
503 	return count;
504 }
505 
506 static long sbprof_tb_ioctl(struct file *filp,
507 			    unsigned int command,
508 			    unsigned long arg)
509 {
510 	int err = 0;
511 
512 	switch (command) {
513 	case SBPROF_ZBSTART:
514 		mutex_lock(&sbp.lock);
515 		err = sbprof_zbprof_start(filp);
516 		mutex_unlock(&sbp.lock);
517 		break;
518 
519 	case SBPROF_ZBSTOP:
520 		mutex_lock(&sbp.lock);
521 		err = sbprof_zbprof_stop();
522 		mutex_unlock(&sbp.lock);
523 		break;
524 
525 	case SBPROF_ZBWAITFULL: {
526 		err = wait_event_interruptible(sbp.tb_read, TB_FULL);
527 		if (err)
528 			break;
529 
530 		err = put_user(TB_FULL, (int *) arg);
531 		break;
532 	}
533 
534 	default:
535 		err = -EINVAL;
536 		break;
537 	}
538 
539 	return err;
540 }
541 
542 static const struct file_operations sbprof_tb_fops = {
543 	.owner		= THIS_MODULE,
544 	.open		= sbprof_tb_open,
545 	.release	= sbprof_tb_release,
546 	.read		= sbprof_tb_read,
547 	.unlocked_ioctl	= sbprof_tb_ioctl,
548 	.compat_ioctl	= sbprof_tb_ioctl,
549 	.mmap		= NULL,
550 };
551 
552 static struct class *tb_class;
553 static struct device *tb_dev;
554 
555 static int __init sbprof_tb_init(void)
556 {
557 	struct device *dev;
558 	struct class *tbc;
559 	int err;
560 
561 	if (register_chrdev(SBPROF_TB_MAJOR, DEVNAME, &sbprof_tb_fops)) {
562 		printk(KERN_WARNING DEVNAME ": initialization failed (dev %d)\n",
563 		       SBPROF_TB_MAJOR);
564 		return -EIO;
565 	}
566 
567 	tbc = class_create(THIS_MODULE, "sb_tracebuffer");
568 	if (IS_ERR(tbc)) {
569 		err = PTR_ERR(tbc);
570 		goto out_chrdev;
571 	}
572 
573 	tb_class = tbc;
574 
575 	dev = device_create(tbc, NULL, MKDEV(SBPROF_TB_MAJOR, 0), NULL, "tb");
576 	if (IS_ERR(dev)) {
577 		err = PTR_ERR(dev);
578 		goto out_class;
579 	}
580 	tb_dev = dev;
581 
582 	sbp.open = SB_CLOSED;
583 	wmb();
584 	tb_period = zbbus_mhz * 10000LL;
585 	pr_info(DEVNAME ": initialized - tb_period = %lld\n",
586 		(long long) tb_period);
587 	return 0;
588 
589 out_class:
590 	class_destroy(tb_class);
591 out_chrdev:
592 	unregister_chrdev(SBPROF_TB_MAJOR, DEVNAME);
593 
594 	return err;
595 }
596 
597 static void __exit sbprof_tb_cleanup(void)
598 {
599 	device_destroy(tb_class, MKDEV(SBPROF_TB_MAJOR, 0));
600 	unregister_chrdev(SBPROF_TB_MAJOR, DEVNAME);
601 	class_destroy(tb_class);
602 }
603 
604 module_init(sbprof_tb_init);
605 module_exit(sbprof_tb_cleanup);
606 
607 MODULE_ALIAS_CHARDEV_MAJOR(SBPROF_TB_MAJOR);
608 MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
609 MODULE_LICENSE("GPL");
610