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