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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * SCOM FSI Client device driver
4  *
5  * Copyright (C) IBM Corporation 2016
6  */
7 
8 #include <linux/fsi.h>
9 #include <linux/module.h>
10 #include <linux/cdev.h>
11 #include <linux/delay.h>
12 #include <linux/fs.h>
13 #include <linux/uaccess.h>
14 #include <linux/slab.h>
15 #include <linux/list.h>
16 
17 #include <uapi/linux/fsi.h>
18 
19 #define FSI_ENGID_SCOM		0x5
20 
21 /* SCOM engine register set */
22 #define SCOM_DATA0_REG		0x00
23 #define SCOM_DATA1_REG		0x04
24 #define SCOM_CMD_REG		0x08
25 #define SCOM_FSI2PIB_RESET_REG	0x18
26 #define SCOM_STATUS_REG		0x1C /* Read */
27 #define SCOM_PIB_RESET_REG	0x1C /* Write */
28 
29 /* Command register */
30 #define SCOM_WRITE_CMD		0x80000000
31 #define SCOM_READ_CMD		0x00000000
32 
33 /* Status register bits */
34 #define SCOM_STATUS_ERR_SUMMARY		0x80000000
35 #define SCOM_STATUS_PROTECTION		0x01000000
36 #define SCOM_STATUS_PARITY		0x04000000
37 #define SCOM_STATUS_PIB_ABORT		0x00100000
38 #define SCOM_STATUS_PIB_RESP_MASK	0x00007000
39 #define SCOM_STATUS_PIB_RESP_SHIFT	12
40 
41 #define SCOM_STATUS_FSI2PIB_ERROR	(SCOM_STATUS_PROTECTION |	\
42 					 SCOM_STATUS_PARITY |		\
43 					 SCOM_STATUS_PIB_ABORT)
44 #define SCOM_STATUS_ANY_ERR		(SCOM_STATUS_FSI2PIB_ERROR |	\
45 					 SCOM_STATUS_PIB_RESP_MASK)
46 /* SCOM address encodings */
47 #define XSCOM_ADDR_IND_FLAG		BIT_ULL(63)
48 #define XSCOM_ADDR_INF_FORM1		BIT_ULL(60)
49 
50 /* SCOM indirect stuff */
51 #define XSCOM_ADDR_DIRECT_PART		0x7fffffffull
52 #define XSCOM_ADDR_INDIRECT_PART	0x000fffff00000000ull
53 #define XSCOM_DATA_IND_READ		BIT_ULL(63)
54 #define XSCOM_DATA_IND_COMPLETE		BIT_ULL(31)
55 #define XSCOM_DATA_IND_ERR_MASK		0x70000000ull
56 #define XSCOM_DATA_IND_ERR_SHIFT	28
57 #define XSCOM_DATA_IND_DATA		0x0000ffffull
58 #define XSCOM_DATA_IND_FORM1_DATA	0x000fffffffffffffull
59 #define XSCOM_ADDR_FORM1_LOW		0x000ffffffffull
60 #define XSCOM_ADDR_FORM1_HI		0xfff00000000ull
61 #define XSCOM_ADDR_FORM1_HI_SHIFT	20
62 
63 /* Retries */
64 #define SCOM_MAX_RETRIES		100	/* Retries on busy */
65 #define SCOM_MAX_IND_RETRIES		10	/* Retries indirect not ready */
66 
67 struct scom_device {
68 	struct list_head link;
69 	struct fsi_device *fsi_dev;
70 	struct device dev;
71 	struct cdev cdev;
72 	struct mutex lock;
73 	bool dead;
74 };
75 
__put_scom(struct scom_device * scom_dev,uint64_t value,uint32_t addr,uint32_t * status)76 static int __put_scom(struct scom_device *scom_dev, uint64_t value,
77 		      uint32_t addr, uint32_t *status)
78 {
79 	__be32 data, raw_status;
80 	int rc;
81 
82 	data = cpu_to_be32((value >> 32) & 0xffffffff);
83 	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
84 				sizeof(uint32_t));
85 	if (rc)
86 		return rc;
87 
88 	data = cpu_to_be32(value & 0xffffffff);
89 	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
90 				sizeof(uint32_t));
91 	if (rc)
92 		return rc;
93 
94 	data = cpu_to_be32(SCOM_WRITE_CMD | addr);
95 	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
96 				sizeof(uint32_t));
97 	if (rc)
98 		return rc;
99 	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status,
100 			     sizeof(uint32_t));
101 	if (rc)
102 		return rc;
103 	*status = be32_to_cpu(raw_status);
104 
105 	return 0;
106 }
107 
__get_scom(struct scom_device * scom_dev,uint64_t * value,uint32_t addr,uint32_t * status)108 static int __get_scom(struct scom_device *scom_dev, uint64_t *value,
109 		      uint32_t addr, uint32_t *status)
110 {
111 	__be32 data, raw_status;
112 	int rc;
113 
114 
115 	*value = 0ULL;
116 	data = cpu_to_be32(SCOM_READ_CMD | addr);
117 	rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data,
118 				sizeof(uint32_t));
119 	if (rc)
120 		return rc;
121 	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_STATUS_REG, &raw_status,
122 			     sizeof(uint32_t));
123 	if (rc)
124 		return rc;
125 
126 	/*
127 	 * Read the data registers even on error, so we don't have
128 	 * to interpret the status register here.
129 	 */
130 	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &data,
131 				sizeof(uint32_t));
132 	if (rc)
133 		return rc;
134 	*value |= (uint64_t)be32_to_cpu(data) << 32;
135 	rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &data,
136 				sizeof(uint32_t));
137 	if (rc)
138 		return rc;
139 	*value |= be32_to_cpu(data);
140 	*status = be32_to_cpu(raw_status);
141 
142 	return rc;
143 }
144 
put_indirect_scom_form0(struct scom_device * scom,uint64_t value,uint64_t addr,uint32_t * status)145 static int put_indirect_scom_form0(struct scom_device *scom, uint64_t value,
146 				   uint64_t addr, uint32_t *status)
147 {
148 	uint64_t ind_data, ind_addr;
149 	int rc, retries, err = 0;
150 
151 	if (value & ~XSCOM_DATA_IND_DATA)
152 		return -EINVAL;
153 
154 	ind_addr = addr & XSCOM_ADDR_DIRECT_PART;
155 	ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | value;
156 	rc = __put_scom(scom, ind_data, ind_addr, status);
157 	if (rc || (*status & SCOM_STATUS_ANY_ERR))
158 		return rc;
159 
160 	for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) {
161 		rc = __get_scom(scom, &ind_data, addr, status);
162 		if (rc || (*status & SCOM_STATUS_ANY_ERR))
163 			return rc;
164 
165 		err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT;
166 		*status = err << SCOM_STATUS_PIB_RESP_SHIFT;
167 		if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED))
168 			return 0;
169 
170 		msleep(1);
171 	}
172 	return rc;
173 }
174 
put_indirect_scom_form1(struct scom_device * scom,uint64_t value,uint64_t addr,uint32_t * status)175 static int put_indirect_scom_form1(struct scom_device *scom, uint64_t value,
176 				   uint64_t addr, uint32_t *status)
177 {
178 	uint64_t ind_data, ind_addr;
179 
180 	if (value & ~XSCOM_DATA_IND_FORM1_DATA)
181 		return -EINVAL;
182 
183 	ind_addr = addr & XSCOM_ADDR_FORM1_LOW;
184 	ind_data = value | (addr & XSCOM_ADDR_FORM1_HI) << XSCOM_ADDR_FORM1_HI_SHIFT;
185 	return __put_scom(scom, ind_data, ind_addr, status);
186 }
187 
get_indirect_scom_form0(struct scom_device * scom,uint64_t * value,uint64_t addr,uint32_t * status)188 static int get_indirect_scom_form0(struct scom_device *scom, uint64_t *value,
189 				   uint64_t addr, uint32_t *status)
190 {
191 	uint64_t ind_data, ind_addr;
192 	int rc, retries, err = 0;
193 
194 	ind_addr = addr & XSCOM_ADDR_DIRECT_PART;
195 	ind_data = (addr & XSCOM_ADDR_INDIRECT_PART) | XSCOM_DATA_IND_READ;
196 	rc = __put_scom(scom, ind_data, ind_addr, status);
197 	if (rc || (*status & SCOM_STATUS_ANY_ERR))
198 		return rc;
199 
200 	for (retries = 0; retries < SCOM_MAX_IND_RETRIES; retries++) {
201 		rc = __get_scom(scom, &ind_data, addr, status);
202 		if (rc || (*status & SCOM_STATUS_ANY_ERR))
203 			return rc;
204 
205 		err = (ind_data & XSCOM_DATA_IND_ERR_MASK) >> XSCOM_DATA_IND_ERR_SHIFT;
206 		*status = err << SCOM_STATUS_PIB_RESP_SHIFT;
207 		*value = ind_data & XSCOM_DATA_IND_DATA;
208 
209 		if ((ind_data & XSCOM_DATA_IND_COMPLETE) || (err != SCOM_PIB_BLOCKED))
210 			return 0;
211 
212 		msleep(1);
213 	}
214 	return rc;
215 }
216 
raw_put_scom(struct scom_device * scom,uint64_t value,uint64_t addr,uint32_t * status)217 static int raw_put_scom(struct scom_device *scom, uint64_t value,
218 			uint64_t addr, uint32_t *status)
219 {
220 	if (addr & XSCOM_ADDR_IND_FLAG) {
221 		if (addr & XSCOM_ADDR_INF_FORM1)
222 			return put_indirect_scom_form1(scom, value, addr, status);
223 		else
224 			return put_indirect_scom_form0(scom, value, addr, status);
225 	} else
226 		return __put_scom(scom, value, addr, status);
227 }
228 
raw_get_scom(struct scom_device * scom,uint64_t * value,uint64_t addr,uint32_t * status)229 static int raw_get_scom(struct scom_device *scom, uint64_t *value,
230 			uint64_t addr, uint32_t *status)
231 {
232 	if (addr & XSCOM_ADDR_IND_FLAG) {
233 		if (addr & XSCOM_ADDR_INF_FORM1)
234 			return -ENXIO;
235 		return get_indirect_scom_form0(scom, value, addr, status);
236 	} else
237 		return __get_scom(scom, value, addr, status);
238 }
239 
handle_fsi2pib_status(struct scom_device * scom,uint32_t status)240 static int handle_fsi2pib_status(struct scom_device *scom, uint32_t status)
241 {
242 	uint32_t dummy = -1;
243 
244 	if (status & SCOM_STATUS_FSI2PIB_ERROR)
245 		fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
246 				 sizeof(uint32_t));
247 
248 	if (status & SCOM_STATUS_PROTECTION)
249 		return -EPERM;
250 	if (status & SCOM_STATUS_PARITY)
251 		return -EIO;
252 	/* Return -EBUSY on PIB abort to force a retry */
253 	if (status & SCOM_STATUS_PIB_ABORT)
254 		return -EBUSY;
255 	return 0;
256 }
257 
handle_pib_status(struct scom_device * scom,uint8_t status)258 static int handle_pib_status(struct scom_device *scom, uint8_t status)
259 {
260 	uint32_t dummy = -1;
261 
262 	if (status == SCOM_PIB_SUCCESS)
263 		return 0;
264 	if (status == SCOM_PIB_BLOCKED)
265 		return -EBUSY;
266 
267 	/* Reset the bridge */
268 	fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
269 			 sizeof(uint32_t));
270 
271 	switch(status) {
272 	case SCOM_PIB_OFFLINE:
273 		return -ENODEV;
274 	case SCOM_PIB_BAD_ADDR:
275 		return -ENXIO;
276 	case SCOM_PIB_TIMEOUT:
277 		return -ETIMEDOUT;
278 	case SCOM_PIB_PARTIAL:
279 	case SCOM_PIB_CLK_ERR:
280 	case SCOM_PIB_PARITY_ERR:
281 	default:
282 		return -EIO;
283 	}
284 }
285 
put_scom(struct scom_device * scom,uint64_t value,uint64_t addr)286 static int put_scom(struct scom_device *scom, uint64_t value,
287 		    uint64_t addr)
288 {
289 	uint32_t status, dummy = -1;
290 	int rc, retries;
291 
292 	for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) {
293 		rc = raw_put_scom(scom, value, addr, &status);
294 		if (rc) {
295 			/* Try resetting the bridge if FSI fails */
296 			if (rc != -ENODEV && retries == 0) {
297 				fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG,
298 						 &dummy, sizeof(uint32_t));
299 				rc = -EBUSY;
300 			} else
301 				return rc;
302 		} else
303 			rc = handle_fsi2pib_status(scom, status);
304 		if (rc && rc != -EBUSY)
305 			break;
306 		if (rc == 0) {
307 			rc = handle_pib_status(scom,
308 					       (status & SCOM_STATUS_PIB_RESP_MASK)
309 					       >> SCOM_STATUS_PIB_RESP_SHIFT);
310 			if (rc && rc != -EBUSY)
311 				break;
312 		}
313 		if (rc == 0)
314 			break;
315 		msleep(1);
316 	}
317 	return rc;
318 }
319 
get_scom(struct scom_device * scom,uint64_t * value,uint64_t addr)320 static int get_scom(struct scom_device *scom, uint64_t *value,
321 		    uint64_t addr)
322 {
323 	uint32_t status, dummy = -1;
324 	int rc, retries;
325 
326 	for (retries = 0; retries < SCOM_MAX_RETRIES; retries++) {
327 		rc = raw_get_scom(scom, value, addr, &status);
328 		if (rc) {
329 			/* Try resetting the bridge if FSI fails */
330 			if (rc != -ENODEV && retries == 0) {
331 				fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG,
332 						 &dummy, sizeof(uint32_t));
333 				rc = -EBUSY;
334 			} else
335 				return rc;
336 		} else
337 			rc = handle_fsi2pib_status(scom, status);
338 		if (rc && rc != -EBUSY)
339 			break;
340 		if (rc == 0) {
341 			rc = handle_pib_status(scom,
342 					       (status & SCOM_STATUS_PIB_RESP_MASK)
343 					       >> SCOM_STATUS_PIB_RESP_SHIFT);
344 			if (rc && rc != -EBUSY)
345 				break;
346 		}
347 		if (rc == 0)
348 			break;
349 		msleep(1);
350 	}
351 	return rc;
352 }
353 
scom_read(struct file * filep,char __user * buf,size_t len,loff_t * offset)354 static ssize_t scom_read(struct file *filep, char __user *buf, size_t len,
355 			 loff_t *offset)
356 {
357 	struct scom_device *scom = filep->private_data;
358 	struct device *dev = &scom->fsi_dev->dev;
359 	uint64_t val;
360 	int rc;
361 
362 	if (len != sizeof(uint64_t))
363 		return -EINVAL;
364 
365 	mutex_lock(&scom->lock);
366 	if (scom->dead)
367 		rc = -ENODEV;
368 	else
369 		rc = get_scom(scom, &val, *offset);
370 	mutex_unlock(&scom->lock);
371 	if (rc) {
372 		dev_dbg(dev, "get_scom fail:%d\n", rc);
373 		return rc;
374 	}
375 
376 	rc = copy_to_user(buf, &val, len);
377 	if (rc)
378 		dev_dbg(dev, "copy to user failed:%d\n", rc);
379 
380 	return rc ? rc : len;
381 }
382 
scom_write(struct file * filep,const char __user * buf,size_t len,loff_t * offset)383 static ssize_t scom_write(struct file *filep, const char __user *buf,
384 			  size_t len, loff_t *offset)
385 {
386 	int rc;
387 	struct scom_device *scom = filep->private_data;
388 	struct device *dev = &scom->fsi_dev->dev;
389 	uint64_t val;
390 
391 	if (len != sizeof(uint64_t))
392 		return -EINVAL;
393 
394 	rc = copy_from_user(&val, buf, len);
395 	if (rc) {
396 		dev_dbg(dev, "copy from user failed:%d\n", rc);
397 		return -EINVAL;
398 	}
399 
400 	mutex_lock(&scom->lock);
401 	if (scom->dead)
402 		rc = -ENODEV;
403 	else
404 		rc = put_scom(scom, val, *offset);
405 	mutex_unlock(&scom->lock);
406 	if (rc) {
407 		dev_dbg(dev, "put_scom failed with:%d\n", rc);
408 		return rc;
409 	}
410 
411 	return len;
412 }
413 
scom_llseek(struct file * file,loff_t offset,int whence)414 static loff_t scom_llseek(struct file *file, loff_t offset, int whence)
415 {
416 	switch (whence) {
417 	case SEEK_CUR:
418 		break;
419 	case SEEK_SET:
420 		file->f_pos = offset;
421 		break;
422 	default:
423 		return -EINVAL;
424 	}
425 
426 	return offset;
427 }
428 
raw_convert_status(struct scom_access * acc,uint32_t status)429 static void raw_convert_status(struct scom_access *acc, uint32_t status)
430 {
431 	acc->pib_status = (status & SCOM_STATUS_PIB_RESP_MASK) >>
432 		SCOM_STATUS_PIB_RESP_SHIFT;
433 	acc->intf_errors = 0;
434 
435 	if (status & SCOM_STATUS_PROTECTION)
436 		acc->intf_errors |= SCOM_INTF_ERR_PROTECTION;
437 	else if (status & SCOM_STATUS_PARITY)
438 		acc->intf_errors |= SCOM_INTF_ERR_PARITY;
439 	else if (status & SCOM_STATUS_PIB_ABORT)
440 		acc->intf_errors |= SCOM_INTF_ERR_ABORT;
441 	else if (status & SCOM_STATUS_ERR_SUMMARY)
442 		acc->intf_errors |= SCOM_INTF_ERR_UNKNOWN;
443 }
444 
scom_raw_read(struct scom_device * scom,void __user * argp)445 static int scom_raw_read(struct scom_device *scom, void __user *argp)
446 {
447 	struct scom_access acc;
448 	uint32_t status;
449 	int rc;
450 
451 	if (copy_from_user(&acc, argp, sizeof(struct scom_access)))
452 		return -EFAULT;
453 
454 	rc = raw_get_scom(scom, &acc.data, acc.addr, &status);
455 	if (rc)
456 		return rc;
457 	raw_convert_status(&acc, status);
458 	if (copy_to_user(argp, &acc, sizeof(struct scom_access)))
459 		return -EFAULT;
460 	return 0;
461 }
462 
scom_raw_write(struct scom_device * scom,void __user * argp)463 static int scom_raw_write(struct scom_device *scom, void __user *argp)
464 {
465 	u64 prev_data, mask, data;
466 	struct scom_access acc;
467 	uint32_t status;
468 	int rc;
469 
470 	if (copy_from_user(&acc, argp, sizeof(struct scom_access)))
471 		return -EFAULT;
472 
473 	if (acc.mask) {
474 		rc = raw_get_scom(scom, &prev_data, acc.addr, &status);
475 		if (rc)
476 			return rc;
477 		if (status & SCOM_STATUS_ANY_ERR)
478 			goto fail;
479 		mask = acc.mask;
480 	} else {
481 		prev_data = mask = -1ull;
482 	}
483 	data = (prev_data & ~mask) | (acc.data & mask);
484 	rc = raw_put_scom(scom, data, acc.addr, &status);
485 	if (rc)
486 		return rc;
487  fail:
488 	raw_convert_status(&acc, status);
489 	if (copy_to_user(argp, &acc, sizeof(struct scom_access)))
490 		return -EFAULT;
491 	return 0;
492 }
493 
scom_reset(struct scom_device * scom,void __user * argp)494 static int scom_reset(struct scom_device *scom, void __user *argp)
495 {
496 	uint32_t flags, dummy = -1;
497 	int rc = 0;
498 
499 	if (get_user(flags, (__u32 __user *)argp))
500 		return -EFAULT;
501 	if (flags & SCOM_RESET_PIB)
502 		rc = fsi_device_write(scom->fsi_dev, SCOM_PIB_RESET_REG, &dummy,
503 				      sizeof(uint32_t));
504 	if (!rc && (flags & (SCOM_RESET_PIB | SCOM_RESET_INTF)))
505 		rc = fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
506 				      sizeof(uint32_t));
507 	return rc;
508 }
509 
scom_check(struct scom_device * scom,void __user * argp)510 static int scom_check(struct scom_device *scom, void __user *argp)
511 {
512 	/* Still need to find out how to get "protected" */
513 	return put_user(SCOM_CHECK_SUPPORTED, (__u32 __user *)argp);
514 }
515 
scom_ioctl(struct file * file,unsigned int cmd,unsigned long arg)516 static long scom_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
517 {
518 	struct scom_device *scom = file->private_data;
519 	void __user *argp = (void __user *)arg;
520 	int rc = -ENOTTY;
521 
522 	mutex_lock(&scom->lock);
523 	if (scom->dead) {
524 		mutex_unlock(&scom->lock);
525 		return -ENODEV;
526 	}
527 	switch(cmd) {
528 	case FSI_SCOM_CHECK:
529 		rc = scom_check(scom, argp);
530 		break;
531 	case FSI_SCOM_READ:
532 		rc = scom_raw_read(scom, argp);
533 		break;
534 	case FSI_SCOM_WRITE:
535 		rc = scom_raw_write(scom, argp);
536 		break;
537 	case FSI_SCOM_RESET:
538 		rc = scom_reset(scom, argp);
539 		break;
540 	}
541 	mutex_unlock(&scom->lock);
542 	return rc;
543 }
544 
scom_open(struct inode * inode,struct file * file)545 static int scom_open(struct inode *inode, struct file *file)
546 {
547 	struct scom_device *scom = container_of(inode->i_cdev, struct scom_device, cdev);
548 
549 	file->private_data = scom;
550 
551 	return 0;
552 }
553 
554 static const struct file_operations scom_fops = {
555 	.owner		= THIS_MODULE,
556 	.open		= scom_open,
557 	.llseek		= scom_llseek,
558 	.read		= scom_read,
559 	.write		= scom_write,
560 	.unlocked_ioctl	= scom_ioctl,
561 };
562 
scom_free(struct device * dev)563 static void scom_free(struct device *dev)
564 {
565 	struct scom_device *scom = container_of(dev, struct scom_device, dev);
566 
567 	put_device(&scom->fsi_dev->dev);
568 	kfree(scom);
569 }
570 
scom_probe(struct device * dev)571 static int scom_probe(struct device *dev)
572 {
573 	struct fsi_device *fsi_dev = to_fsi_dev(dev);
574 	struct scom_device *scom;
575 	int rc, didx;
576 
577 	scom = kzalloc(sizeof(*scom), GFP_KERNEL);
578 	if (!scom)
579 		return -ENOMEM;
580 	dev_set_drvdata(dev, scom);
581 	mutex_init(&scom->lock);
582 
583 	/* Grab a reference to the device (parent of our cdev), we'll drop it later */
584 	if (!get_device(dev)) {
585 		kfree(scom);
586 		return -ENODEV;
587 	}
588 	scom->fsi_dev = fsi_dev;
589 
590 	/* Create chardev for userspace access */
591 	scom->dev.type = &fsi_cdev_type;
592 	scom->dev.parent = dev;
593 	scom->dev.release = scom_free;
594 	device_initialize(&scom->dev);
595 
596 	/* Allocate a minor in the FSI space */
597 	rc = fsi_get_new_minor(fsi_dev, fsi_dev_scom, &scom->dev.devt, &didx);
598 	if (rc)
599 		goto err;
600 
601 	dev_set_name(&scom->dev, "scom%d", didx);
602 	cdev_init(&scom->cdev, &scom_fops);
603 	rc = cdev_device_add(&scom->cdev, &scom->dev);
604 	if (rc) {
605 		dev_err(dev, "Error %d creating char device %s\n",
606 			rc, dev_name(&scom->dev));
607 		goto err_free_minor;
608 	}
609 
610 	return 0;
611  err_free_minor:
612 	fsi_free_minor(scom->dev.devt);
613  err:
614 	put_device(&scom->dev);
615 	return rc;
616 }
617 
scom_remove(struct device * dev)618 static int scom_remove(struct device *dev)
619 {
620 	struct scom_device *scom = dev_get_drvdata(dev);
621 
622 	mutex_lock(&scom->lock);
623 	scom->dead = true;
624 	mutex_unlock(&scom->lock);
625 	cdev_device_del(&scom->cdev, &scom->dev);
626 	fsi_free_minor(scom->dev.devt);
627 	put_device(&scom->dev);
628 
629 	return 0;
630 }
631 
632 static const struct fsi_device_id scom_ids[] = {
633 	{
634 		.engine_type = FSI_ENGID_SCOM,
635 		.version = FSI_VERSION_ANY,
636 	},
637 	{ 0 }
638 };
639 
640 static struct fsi_driver scom_drv = {
641 	.id_table = scom_ids,
642 	.drv = {
643 		.name = "scom",
644 		.bus = &fsi_bus_type,
645 		.probe = scom_probe,
646 		.remove = scom_remove,
647 	}
648 };
649 
scom_init(void)650 static int scom_init(void)
651 {
652 	return fsi_driver_register(&scom_drv);
653 }
654 
scom_exit(void)655 static void scom_exit(void)
656 {
657 	fsi_driver_unregister(&scom_drv);
658 }
659 
660 module_init(scom_init);
661 module_exit(scom_exit);
662 MODULE_LICENSE("GPL");
663