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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / fsi / fsi-core.c
blob8244da8a72411feb55d90a5d5a75f39bd438f564
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * FSI core driver
4 *
5 * Copyright (C) IBM Corporation 2016
6 *
7 * TODO:
8 * - Rework topology
9 * - s/chip_id/chip_loc
10 * - s/cfam/chip (cfam_id -> chip_id etc...)
11 */
12
13 #include <linux/crc4.h>
14 #include <linux/device.h>
15 #include <linux/fsi.h>
16 #include <linux/idr.h>
17 #include <linux/module.h>
18 #include <linux/of.h>
19 #include <linux/slab.h>
20 #include <linux/bitops.h>
21 #include <linux/cdev.h>
22 #include <linux/fs.h>
23 #include <linux/uaccess.h>
24
25 #include "fsi-master.h"
26
27 #define CREATE_TRACE_POINTS
28 #include <trace/events/fsi.h>
29
30 #define FSI_SLAVE_CONF_NEXT_MASK GENMASK(31, 31)
31 #define FSI_SLAVE_CONF_SLOTS_MASK GENMASK(23, 16)
32 #define FSI_SLAVE_CONF_SLOTS_SHIFT 16
33 #define FSI_SLAVE_CONF_VERSION_MASK GENMASK(15, 12)
34 #define FSI_SLAVE_CONF_VERSION_SHIFT 12
35 #define FSI_SLAVE_CONF_TYPE_MASK GENMASK(11, 4)
36 #define FSI_SLAVE_CONF_TYPE_SHIFT 4
37 #define FSI_SLAVE_CONF_CRC_SHIFT 4
38 #define FSI_SLAVE_CONF_CRC_MASK GENMASK(3, 0)
39 #define FSI_SLAVE_CONF_DATA_BITS 28
40
41 #define FSI_PEEK_BASE 0x410
42
43 static const int engine_page_size = 0x400;
44
45 #define FSI_SLAVE_BASE 0x800
46
47 /*
48 * FSI slave engine control register offsets
49 */
50 #define FSI_SMODE 0x0 /* R/W: Mode register */
51 #define FSI_SISC 0x8 /* R/W: Interrupt condition */
52 #define FSI_SSTAT 0x14 /* R : Slave status */
53 #define FSI_LLMODE 0x100 /* R/W: Link layer mode register */
54
55 /*
56 * SMODE fields
57 */
58 #define FSI_SMODE_WSC 0x80000000 /* Warm start done */
59 #define FSI_SMODE_ECRC 0x20000000 /* Hw CRC check */
60 #define FSI_SMODE_SID_SHIFT 24 /* ID shift */
61 #define FSI_SMODE_SID_MASK 3 /* ID Mask */
62 #define FSI_SMODE_ED_SHIFT 20 /* Echo delay shift */
63 #define FSI_SMODE_ED_MASK 0xf /* Echo delay mask */
64 #define FSI_SMODE_SD_SHIFT 16 /* Send delay shift */
65 #define FSI_SMODE_SD_MASK 0xf /* Send delay mask */
66 #define FSI_SMODE_LBCRR_SHIFT 8 /* Clk ratio shift */
67 #define FSI_SMODE_LBCRR_MASK 0xf /* Clk ratio mask */
68
69 /*
70 * LLMODE fields
71 */
72 #define FSI_LLMODE_ASYNC 0x1
73
74 #define FSI_SLAVE_SIZE_23b 0x800000
75
76 static DEFINE_IDA(master_ida);
77
78 struct fsi_slave {
79 struct device dev;
80 struct fsi_master *master;
81 struct cdev cdev;
82 int cdev_idx;
83 int id; /* FSI address */
84 int link; /* FSI link# */
85 u32 cfam_id;
86 int chip_id;
87 uint32_t size; /* size of slave address space */
88 u8 t_send_delay;
89 u8 t_echo_delay;
90 };
91
92 #define to_fsi_master(d) container_of(d, struct fsi_master, dev)
93 #define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)
94
95 static const int slave_retries = 2;
96 static int discard_errors;
97
98 static dev_t fsi_base_dev;
99 static DEFINE_IDA(fsi_minor_ida);
100 #define FSI_CHAR_MAX_DEVICES 0x1000
101
102 /* Legacy /dev numbering: 4 devices per chip, 16 chips */
103 #define FSI_CHAR_LEGACY_TOP 64
104
105 static int fsi_master_read(struct fsi_master *master, int link,
106 uint8_t slave_id, uint32_t addr, void *val, size_t size);
107 static int fsi_master_write(struct fsi_master *master, int link,
108 uint8_t slave_id, uint32_t addr, const void *val, size_t size);
109 static int fsi_master_break(struct fsi_master *master, int link);
110
111 /*
112 * fsi_device_read() / fsi_device_write() / fsi_device_peek()
113 *
114 * FSI endpoint-device support
115 *
116 * Read / write / peek accessors for a client
117 *
118 * Parameters:
119 * dev: Structure passed to FSI client device drivers on probe().
120 * addr: FSI address of given device. Client should pass in its base address
121 * plus desired offset to access its register space.
122 * val: For read/peek this is the value read at the specified address. For
123 * write this is value to write to the specified address.
124 * The data in val must be FSI bus endian (big endian).
125 * size: Size in bytes of the operation. Sizes supported are 1, 2 and 4 bytes.
126 * Addresses must be aligned on size boundaries or an error will result.
127 */
128 int fsi_device_read(struct fsi_device *dev, uint32_t addr, void *val,
129 size_t size)
130 {
131 if (addr > dev->size || size > dev->size || addr > dev->size - size)
132 return -EINVAL;
133
134 return fsi_slave_read(dev->slave, dev->addr + addr, val, size);
135 }
136 EXPORT_SYMBOL_GPL(fsi_device_read);
137
138 int fsi_device_write(struct fsi_device *dev, uint32_t addr, const void *val,
139 size_t size)
140 {
141 if (addr > dev->size || size > dev->size || addr > dev->size - size)
142 return -EINVAL;
143
144 return fsi_slave_write(dev->slave, dev->addr + addr, val, size);
145 }
146 EXPORT_SYMBOL_GPL(fsi_device_write);
147
148 int fsi_device_peek(struct fsi_device *dev, void *val)
149 {
150 uint32_t addr = FSI_PEEK_BASE + ((dev->unit - 2) * sizeof(uint32_t));
151
152 return fsi_slave_read(dev->slave, addr, val, sizeof(uint32_t));
153 }
154
155 static void fsi_device_release(struct device *_device)
156 {
157 struct fsi_device *device = to_fsi_dev(_device);
158
159 of_node_put(device->dev.of_node);
160 kfree(device);
161 }
162
163 static struct fsi_device *fsi_create_device(struct fsi_slave *slave)
164 {
165 struct fsi_device *dev;
166
167 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
168 if (!dev)
169 return NULL;
170
171 dev->dev.parent = &slave->dev;
172 dev->dev.bus = &fsi_bus_type;
173 dev->dev.release = fsi_device_release;
174
175 return dev;
176 }
177
178 /* FSI slave support */
179 static int fsi_slave_calc_addr(struct fsi_slave *slave, uint32_t *addrp,
180 uint8_t *idp)
181 {
182 uint32_t addr = *addrp;
183 uint8_t id = *idp;
184
185 if (addr > slave->size)
186 return -EINVAL;
187
188 /* For 23 bit addressing, we encode the extra two bits in the slave
189 * id (and the slave's actual ID needs to be 0).
190 */
191 if (addr > 0x1fffff) {
192 if (slave->id != 0)
193 return -EINVAL;
194 id = (addr >> 21) & 0x3;
195 addr &= 0x1fffff;
196 }
197
198 *addrp = addr;
199 *idp = id;
200 return 0;
201 }
202
203 static int fsi_slave_report_and_clear_errors(struct fsi_slave *slave)
204 {
205 struct fsi_master *master = slave->master;
206 __be32 irq, stat;
207 int rc, link;
208 uint8_t id;
209
210 link = slave->link;
211 id = slave->id;
212
213 rc = fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
214 &irq, sizeof(irq));
215 if (rc)
216 return rc;
217
218 rc = fsi_master_read(master, link, id, FSI_SLAVE_BASE + FSI_SSTAT,
219 &stat, sizeof(stat));
220 if (rc)
221 return rc;
222
223 dev_dbg(&slave->dev, "status: 0x%08x, sisc: 0x%08x\n",
224 be32_to_cpu(stat), be32_to_cpu(irq));
225
226 /* clear interrupts */
227 return fsi_master_write(master, link, id, FSI_SLAVE_BASE + FSI_SISC,
228 &irq, sizeof(irq));
229 }
230
231 /* Encode slave local bus echo delay */
232 static inline uint32_t fsi_smode_echodly(int x)
233 {
234 return (x & FSI_SMODE_ED_MASK) << FSI_SMODE_ED_SHIFT;
235 }
236
237 /* Encode slave local bus send delay */
238 static inline uint32_t fsi_smode_senddly(int x)
239 {
240 return (x & FSI_SMODE_SD_MASK) << FSI_SMODE_SD_SHIFT;
241 }
242
243 /* Encode slave local bus clock rate ratio */
244 static inline uint32_t fsi_smode_lbcrr(int x)
245 {
246 return (x & FSI_SMODE_LBCRR_MASK) << FSI_SMODE_LBCRR_SHIFT;
247 }
248
249 /* Encode slave ID */
250 static inline uint32_t fsi_smode_sid(int x)
251 {
252 return (x & FSI_SMODE_SID_MASK) << FSI_SMODE_SID_SHIFT;
253 }
254
255 static uint32_t fsi_slave_smode(int id, u8 t_senddly, u8 t_echodly)
256 {
257 return FSI_SMODE_WSC | FSI_SMODE_ECRC
258 | fsi_smode_sid(id)
259 | fsi_smode_echodly(t_echodly - 1) | fsi_smode_senddly(t_senddly - 1)
260 | fsi_smode_lbcrr(0x8);
261 }
262
263 static int fsi_slave_set_smode(struct fsi_slave *slave)
264 {
265 uint32_t smode;
266 __be32 data;
267
268 /* set our smode register with the slave ID field to 0; this enables
269 * extended slave addressing
270 */
271 smode = fsi_slave_smode(slave->id, slave->t_send_delay, slave->t_echo_delay);
272 data = cpu_to_be32(smode);
273
274 return fsi_master_write(slave->master, slave->link, slave->id,
275 FSI_SLAVE_BASE + FSI_SMODE,
276 &data, sizeof(data));
277 }
278
279 static int fsi_slave_handle_error(struct fsi_slave *slave, bool write,
280 uint32_t addr, size_t size)
281 {
282 struct fsi_master *master = slave->master;
283 int rc, link;
284 uint32_t reg;
285 uint8_t id, send_delay, echo_delay;
286
287 if (discard_errors)
288 return -1;
289
290 link = slave->link;
291 id = slave->id;
292
293 dev_dbg(&slave->dev, "handling error on %s to 0x%08x[%zd]",
294 write ? "write" : "read", addr, size);
295
296 /* try a simple clear of error conditions, which may fail if we've lost
297 * communication with the slave
298 */
299 rc = fsi_slave_report_and_clear_errors(slave);
300 if (!rc)
301 return 0;
302
303 /* send a TERM and retry */
304 if (master->term) {
305 rc = master->term(master, link, id);
306 if (!rc) {
307 rc = fsi_master_read(master, link, id, 0,
308 &reg, sizeof(reg));
309 if (!rc)
310 rc = fsi_slave_report_and_clear_errors(slave);
311 if (!rc)
312 return 0;
313 }
314 }
315
316 send_delay = slave->t_send_delay;
317 echo_delay = slave->t_echo_delay;
318
319 /* getting serious, reset the slave via BREAK */
320 rc = fsi_master_break(master, link);
321 if (rc)
322 return rc;
323
324 slave->t_send_delay = send_delay;
325 slave->t_echo_delay = echo_delay;
326
327 rc = fsi_slave_set_smode(slave);
328 if (rc)
329 return rc;
330
331 if (master->link_config)
332 master->link_config(master, link,
333 slave->t_send_delay,
334 slave->t_echo_delay);
335
336 return fsi_slave_report_and_clear_errors(slave);
337 }
338
339 int fsi_slave_read(struct fsi_slave *slave, uint32_t addr,
340 void *val, size_t size)
341 {
342 uint8_t id = slave->id;
343 int rc, err_rc, i;
344
345 rc = fsi_slave_calc_addr(slave, &addr, &id);
346 if (rc)
347 return rc;
348
349 for (i = 0; i < slave_retries; i++) {
350 rc = fsi_master_read(slave->master, slave->link,
351 id, addr, val, size);
352 if (!rc)
353 break;
354
355 err_rc = fsi_slave_handle_error(slave, false, addr, size);
356 if (err_rc)
357 break;
358 }
359
360 return rc;
361 }
362 EXPORT_SYMBOL_GPL(fsi_slave_read);
363
364 int fsi_slave_write(struct fsi_slave *slave, uint32_t addr,
365 const void *val, size_t size)
366 {
367 uint8_t id = slave->id;
368 int rc, err_rc, i;
369
370 rc = fsi_slave_calc_addr(slave, &addr, &id);
371 if (rc)
372 return rc;
373
374 for (i = 0; i < slave_retries; i++) {
375 rc = fsi_master_write(slave->master, slave->link,
376 id, addr, val, size);
377 if (!rc)
378 break;
379
380 err_rc = fsi_slave_handle_error(slave, true, addr, size);
381 if (err_rc)
382 break;
383 }
384
385 return rc;
386 }
387 EXPORT_SYMBOL_GPL(fsi_slave_write);
388
389 extern int fsi_slave_claim_range(struct fsi_slave *slave,
390 uint32_t addr, uint32_t size)
391 {
392 if (addr + size < addr)
393 return -EINVAL;
394
395 if (addr + size > slave->size)
396 return -EINVAL;
397
398 /* todo: check for overlapping claims */
399 return 0;
400 }
401 EXPORT_SYMBOL_GPL(fsi_slave_claim_range);
402
403 extern void fsi_slave_release_range(struct fsi_slave *slave,
404 uint32_t addr, uint32_t size)
405 {
406 }
407 EXPORT_SYMBOL_GPL(fsi_slave_release_range);
408
409 static bool fsi_device_node_matches(struct device *dev, struct device_node *np,
410 uint32_t addr, uint32_t size)
411 {
412 unsigned int len, na, ns;
413 const __be32 *prop;
414 uint32_t psize;
415
416 na = of_n_addr_cells(np);
417 ns = of_n_size_cells(np);
418
419 if (na != 1 || ns != 1)
420 return false;
421
422 prop = of_get_property(np, "reg", &len);
423 if (!prop || len != 8)
424 return false;
425
426 if (of_read_number(prop, 1) != addr)
427 return false;
428
429 psize = of_read_number(prop + 1, 1);
430 if (psize != size) {
431 dev_warn(dev,
432 "node %s matches probed address, but not size (got 0x%x, expected 0x%x)",
433 of_node_full_name(np), psize, size);
434 }
435
436 return true;
437 }
438
439 /* Find a matching node for the slave engine at @address, using @size bytes
440 * of space. Returns NULL if not found, or a matching node with refcount
441 * already incremented.
442 */
443 static struct device_node *fsi_device_find_of_node(struct fsi_device *dev)
444 {
445 struct device_node *parent, *np;
446
447 parent = dev_of_node(&dev->slave->dev);
448 if (!parent)
449 return NULL;
450
451 for_each_child_of_node(parent, np) {
452 if (fsi_device_node_matches(&dev->dev, np,
453 dev->addr, dev->size))
454 return np;
455 }
456
457 return NULL;
458 }
459
460 static int fsi_slave_scan(struct fsi_slave *slave)
461 {
462 uint32_t engine_addr;
463 int rc, i;
464
465 /*
466 * scan engines
467 *
468 * We keep the peek mode and slave engines for the core; so start
469 * at the third slot in the configuration table. We also need to
470 * skip the chip ID entry at the start of the address space.
471 */
472 engine_addr = engine_page_size * 3;
473 for (i = 2; i < engine_page_size / sizeof(uint32_t); i++) {
474 uint8_t slots, version, type, crc;
475 struct fsi_device *dev;
476 uint32_t conf;
477 __be32 data;
478
479 rc = fsi_slave_read(slave, (i + 1) * sizeof(data),
480 &data, sizeof(data));
481 if (rc) {
482 dev_warn(&slave->dev,
483 "error reading slave registers\n");
484 return -1;
485 }
486 conf = be32_to_cpu(data);
487
488 crc = crc4(0, conf, 32);
489 if (crc) {
490 dev_warn(&slave->dev,
491 "crc error in slave register at 0x%04x\n",
492 i);
493 return -1;
494 }
495
496 slots = (conf & FSI_SLAVE_CONF_SLOTS_MASK)
497 >> FSI_SLAVE_CONF_SLOTS_SHIFT;
498 version = (conf & FSI_SLAVE_CONF_VERSION_MASK)
499 >> FSI_SLAVE_CONF_VERSION_SHIFT;
500 type = (conf & FSI_SLAVE_CONF_TYPE_MASK)
501 >> FSI_SLAVE_CONF_TYPE_SHIFT;
502
503 /*
504 * Unused address areas are marked by a zero type value; this
505 * skips the defined address areas
506 */
507 if (type != 0 && slots != 0) {
508
509 /* create device */
510 dev = fsi_create_device(slave);
511 if (!dev)
512 return -ENOMEM;
513
514 dev->slave = slave;
515 dev->engine_type = type;
516 dev->version = version;
517 dev->unit = i;
518 dev->addr = engine_addr;
519 dev->size = slots * engine_page_size;
520
521 dev_dbg(&slave->dev,
522 "engine[%i]: type %x, version %x, addr %x size %x\n",
523 dev->unit, dev->engine_type, version,
524 dev->addr, dev->size);
525
526 dev_set_name(&dev->dev, "%02x:%02x:%02x:%02x",
527 slave->master->idx, slave->link,
528 slave->id, i - 2);
529 dev->dev.of_node = fsi_device_find_of_node(dev);
530
531 rc = device_register(&dev->dev);
532 if (rc) {
533 dev_warn(&slave->dev, "add failed: %d\n", rc);
534 put_device(&dev->dev);
535 }
536 }
537
538 engine_addr += slots * engine_page_size;
539
540 if (!(conf & FSI_SLAVE_CONF_NEXT_MASK))
541 break;
542 }
543
544 return 0;
545 }
546
547 static unsigned long aligned_access_size(size_t offset, size_t count)
548 {
549 unsigned long offset_unit, count_unit;
550
551 /* Criteria:
552 *
553 * 1. Access size must be less than or equal to the maximum access
554 * width or the highest power-of-two factor of offset
555 * 2. Access size must be less than or equal to the amount specified by
556 * count
557 *
558 * The access width is optimal if we can calculate 1 to be strictly
559 * equal while still satisfying 2.
560 */
561
562 /* Find 1 by the bottom bit of offset (with a 4 byte access cap) */
563 offset_unit = BIT(__builtin_ctzl(offset | 4));
564
565 /* Find 2 by the top bit of count */
566 count_unit = BIT(8 * sizeof(unsigned long) - 1 - __builtin_clzl(count));
567
568 /* Constrain the maximum access width to the minimum of both criteria */
569 return BIT(__builtin_ctzl(offset_unit | count_unit));
570 }
571
572 static ssize_t fsi_slave_sysfs_raw_read(struct file *file,
573 struct kobject *kobj, struct bin_attribute *attr, char *buf,
574 loff_t off, size_t count)
575 {
576 struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
577 size_t total_len, read_len;
578 int rc;
579
580 if (off < 0)
581 return -EINVAL;
582
583 if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
584 return -EINVAL;
585
586 for (total_len = 0; total_len < count; total_len += read_len) {
587 read_len = aligned_access_size(off, count - total_len);
588
589 rc = fsi_slave_read(slave, off, buf + total_len, read_len);
590 if (rc)
591 return rc;
592
593 off += read_len;
594 }
595
596 return count;
597 }
598
599 static ssize_t fsi_slave_sysfs_raw_write(struct file *file,
600 struct kobject *kobj, struct bin_attribute *attr,
601 char *buf, loff_t off, size_t count)
602 {
603 struct fsi_slave *slave = to_fsi_slave(kobj_to_dev(kobj));
604 size_t total_len, write_len;
605 int rc;
606
607 if (off < 0)
608 return -EINVAL;
609
610 if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
611 return -EINVAL;
612
613 for (total_len = 0; total_len < count; total_len += write_len) {
614 write_len = aligned_access_size(off, count - total_len);
615
616 rc = fsi_slave_write(slave, off, buf + total_len, write_len);
617 if (rc)
618 return rc;
619
620 off += write_len;
621 }
622
623 return count;
624 }
625
626 static const struct bin_attribute fsi_slave_raw_attr = {
627 .attr = {
628 .name = "raw",
629 .mode = 0600,
630 },
631 .size = 0,
632 .read = fsi_slave_sysfs_raw_read,
633 .write = fsi_slave_sysfs_raw_write,
634 };
635
636 static void fsi_slave_release(struct device *dev)
637 {
638 struct fsi_slave *slave = to_fsi_slave(dev);
639
640 fsi_free_minor(slave->dev.devt);
641 of_node_put(dev->of_node);
642 kfree(slave);
643 }
644
645 static bool fsi_slave_node_matches(struct device_node *np,
646 int link, uint8_t id)
647 {
648 unsigned int len, na, ns;
649 const __be32 *prop;
650
651 na = of_n_addr_cells(np);
652 ns = of_n_size_cells(np);
653
654 /* Ensure we have the correct format for addresses and sizes in
655 * reg properties
656 */
657 if (na != 2 || ns != 0)
658 return false;
659
660 prop = of_get_property(np, "reg", &len);
661 if (!prop || len != 8)
662 return false;
663
664 return (of_read_number(prop, 1) == link) &&
665 (of_read_number(prop + 1, 1) == id);
666 }
667
668 /* Find a matching node for the slave at (link, id). Returns NULL if none
669 * found, or a matching node with refcount already incremented.
670 */
671 static struct device_node *fsi_slave_find_of_node(struct fsi_master *master,
672 int link, uint8_t id)
673 {
674 struct device_node *parent, *np;
675
676 parent = dev_of_node(&master->dev);
677 if (!parent)
678 return NULL;
679
680 for_each_child_of_node(parent, np) {
681 if (fsi_slave_node_matches(np, link, id))
682 return np;
683 }
684
685 return NULL;
686 }
687
688 static ssize_t cfam_read(struct file *filep, char __user *buf, size_t count,
689 loff_t *offset)
690 {
691 struct fsi_slave *slave = filep->private_data;
692 size_t total_len, read_len;
693 loff_t off = *offset;
694 ssize_t rc;
695
696 if (off < 0)
697 return -EINVAL;
698
699 if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
700 return -EINVAL;
701
702 for (total_len = 0; total_len < count; total_len += read_len) {
703 __be32 data;
704
705 read_len = min_t(size_t, count, 4);
706 read_len -= off & 0x3;
707
708 rc = fsi_slave_read(slave, off, &data, read_len);
709 if (rc)
710 goto fail;
711 rc = copy_to_user(buf + total_len, &data, read_len);
712 if (rc) {
713 rc = -EFAULT;
714 goto fail;
715 }
716 off += read_len;
717 }
718 rc = count;
719 fail:
720 *offset = off;
721 return count;
722 }
723
724 static ssize_t cfam_write(struct file *filep, const char __user *buf,
725 size_t count, loff_t *offset)
726 {
727 struct fsi_slave *slave = filep->private_data;
728 size_t total_len, write_len;
729 loff_t off = *offset;
730 ssize_t rc;
731
732
733 if (off < 0)
734 return -EINVAL;
735
736 if (off > 0xffffffff || count > 0xffffffff || off + count > 0xffffffff)
737 return -EINVAL;
738
739 for (total_len = 0; total_len < count; total_len += write_len) {
740 __be32 data;
741
742 write_len = min_t(size_t, count, 4);
743 write_len -= off & 0x3;
744
745 rc = copy_from_user(&data, buf + total_len, write_len);
746 if (rc) {
747 rc = -EFAULT;
748 goto fail;
749 }
750 rc = fsi_slave_write(slave, off, &data, write_len);
751 if (rc)
752 goto fail;
753 off += write_len;
754 }
755 rc = count;
756 fail:
757 *offset = off;
758 return count;
759 }
760
761 static loff_t cfam_llseek(struct file *file, loff_t offset, int whence)
762 {
763 switch (whence) {
764 case SEEK_CUR:
765 break;
766 case SEEK_SET:
767 file->f_pos = offset;
768 break;
769 default:
770 return -EINVAL;
771 }
772
773 return offset;
774 }
775
776 static int cfam_open(struct inode *inode, struct file *file)
777 {
778 struct fsi_slave *slave = container_of(inode->i_cdev, struct fsi_slave, cdev);
779
780 file->private_data = slave;
781
782 return 0;
783 }
784
785 static const struct file_operations cfam_fops = {
786 .owner = THIS_MODULE,
787 .open = cfam_open,
788 .llseek = cfam_llseek,
789 .read = cfam_read,
790 .write = cfam_write,
791 };
792
793 static ssize_t send_term_store(struct device *dev,
794 struct device_attribute *attr,
795 const char *buf, size_t count)
796 {
797 struct fsi_slave *slave = to_fsi_slave(dev);
798 struct fsi_master *master = slave->master;
799
800 if (!master->term)
801 return -ENODEV;
802
803 master->term(master, slave->link, slave->id);
804 return count;
805 }
806
807 static DEVICE_ATTR_WO(send_term);
808
809 static ssize_t slave_send_echo_show(struct device *dev,
810 struct device_attribute *attr,
811 char *buf)
812 {
813 struct fsi_slave *slave = to_fsi_slave(dev);
814
815 return sprintf(buf, "%u\n", slave->t_send_delay);
816 }
817
818 static ssize_t slave_send_echo_store(struct device *dev,
819 struct device_attribute *attr, const char *buf, size_t count)
820 {
821 struct fsi_slave *slave = to_fsi_slave(dev);
822 struct fsi_master *master = slave->master;
823 unsigned long val;
824 int rc;
825
826 if (kstrtoul(buf, 0, &val) < 0)
827 return -EINVAL;
828
829 if (val < 1 || val > 16)
830 return -EINVAL;
831
832 if (!master->link_config)
833 return -ENXIO;
834
835 /* Current HW mandates that send and echo delay are identical */
836 slave->t_send_delay = val;
837 slave->t_echo_delay = val;
838
839 rc = fsi_slave_set_smode(slave);
840 if (rc < 0)
841 return rc;
842 if (master->link_config)
843 master->link_config(master, slave->link,
844 slave->t_send_delay,
845 slave->t_echo_delay);
846
847 return count;
848 }
849
850 static DEVICE_ATTR(send_echo_delays, 0600,
851 slave_send_echo_show, slave_send_echo_store);
852
853 static ssize_t chip_id_show(struct device *dev,
854 struct device_attribute *attr,
855 char *buf)
856 {
857 struct fsi_slave *slave = to_fsi_slave(dev);
858
859 return sprintf(buf, "%d\n", slave->chip_id);
860 }
861
862 static DEVICE_ATTR_RO(chip_id);
863
864 static ssize_t cfam_id_show(struct device *dev,
865 struct device_attribute *attr,
866 char *buf)
867 {
868 struct fsi_slave *slave = to_fsi_slave(dev);
869
870 return sprintf(buf, "0x%x\n", slave->cfam_id);
871 }
872
873 static DEVICE_ATTR_RO(cfam_id);
874
875 static struct attribute *cfam_attr[] = {
876 &dev_attr_send_echo_delays.attr,
877 &dev_attr_chip_id.attr,
878 &dev_attr_cfam_id.attr,
879 &dev_attr_send_term.attr,
880 NULL,
881 };
882
883 static const struct attribute_group cfam_attr_group = {
884 .attrs = cfam_attr,
885 };
886
887 static const struct attribute_group *cfam_attr_groups[] = {
888 &cfam_attr_group,
889 NULL,
890 };
891
892 static char *cfam_devnode(struct device *dev, umode_t *mode,
893 kuid_t *uid, kgid_t *gid)
894 {
895 struct fsi_slave *slave = to_fsi_slave(dev);
896
897 #ifdef CONFIG_FSI_NEW_DEV_NODE
898 return kasprintf(GFP_KERNEL, "fsi/cfam%d", slave->cdev_idx);
899 #else
900 return kasprintf(GFP_KERNEL, "cfam%d", slave->cdev_idx);
901 #endif
902 }
903
904 static const struct device_type cfam_type = {
905 .name = "cfam",
906 .devnode = cfam_devnode,
907 .groups = cfam_attr_groups
908 };
909
910 static char *fsi_cdev_devnode(struct device *dev, umode_t *mode,
911 kuid_t *uid, kgid_t *gid)
912 {
913 #ifdef CONFIG_FSI_NEW_DEV_NODE
914 return kasprintf(GFP_KERNEL, "fsi/%s", dev_name(dev));
915 #else
916 return kasprintf(GFP_KERNEL, "%s", dev_name(dev));
917 #endif
918 }
919
920 const struct device_type fsi_cdev_type = {
921 .name = "fsi-cdev",
922 .devnode = fsi_cdev_devnode,
923 };
924 EXPORT_SYMBOL_GPL(fsi_cdev_type);
925
926 /* Backward compatible /dev/ numbering in "old style" mode */
927 static int fsi_adjust_index(int index)
928 {
929 #ifdef CONFIG_FSI_NEW_DEV_NODE
930 return index;
931 #else
932 return index + 1;
933 #endif
934 }
935
936 static int __fsi_get_new_minor(struct fsi_slave *slave, enum fsi_dev_type type,
937 dev_t *out_dev, int *out_index)
938 {
939 int cid = slave->chip_id;
940 int id;
941
942 /* Check if we qualify for legacy numbering */
943 if (cid >= 0 && cid < 16 && type < 4) {
944 /* Try reserving the legacy number */
945 id = (cid << 4) | type;
946 id = ida_simple_get(&fsi_minor_ida, id, id + 1, GFP_KERNEL);
947 if (id >= 0) {
948 *out_index = fsi_adjust_index(cid);
949 *out_dev = fsi_base_dev + id;
950 return 0;
951 }
952 /* Other failure */
953 if (id != -ENOSPC)
954 return id;
955 /* Fallback to non-legacy allocation */
956 }
957 id = ida_simple_get(&fsi_minor_ida, FSI_CHAR_LEGACY_TOP,
958 FSI_CHAR_MAX_DEVICES, GFP_KERNEL);
959 if (id < 0)
960 return id;
961 *out_index = fsi_adjust_index(id);
962 *out_dev = fsi_base_dev + id;
963 return 0;
964 }
965
966 int fsi_get_new_minor(struct fsi_device *fdev, enum fsi_dev_type type,
967 dev_t *out_dev, int *out_index)
968 {
969 return __fsi_get_new_minor(fdev->slave, type, out_dev, out_index);
970 }
971 EXPORT_SYMBOL_GPL(fsi_get_new_minor);
972
973 void fsi_free_minor(dev_t dev)
974 {
975 ida_simple_remove(&fsi_minor_ida, MINOR(dev));
976 }
977 EXPORT_SYMBOL_GPL(fsi_free_minor);
978
979 static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id)
980 {
981 uint32_t cfam_id;
982 struct fsi_slave *slave;
983 uint8_t crc;
984 __be32 data, llmode;
985 int rc;
986
987 /* Currently, we only support single slaves on a link, and use the
988 * full 23-bit address range
989 */
990 if (id != 0)
991 return -EINVAL;
992
993 rc = fsi_master_read(master, link, id, 0, &data, sizeof(data));
994 if (rc) {
995 dev_dbg(&master->dev, "can't read slave %02x:%02x %d\n",
996 link, id, rc);
997 return -ENODEV;
998 }
999 cfam_id = be32_to_cpu(data);
1000
1001 crc = crc4(0, cfam_id, 32);
1002 if (crc) {
1003 dev_warn(&master->dev, "slave %02x:%02x invalid cfam id CRC!\n",
1004 link, id);
1005 return -EIO;
1006 }
1007
1008 dev_dbg(&master->dev, "fsi: found chip %08x at %02x:%02x:%02x\n",
1009 cfam_id, master->idx, link, id);
1010
1011 /* If we're behind a master that doesn't provide a self-running bus
1012 * clock, put the slave into async mode
1013 */
1014 if (master->flags & FSI_MASTER_FLAG_SWCLOCK) {
1015 llmode = cpu_to_be32(FSI_LLMODE_ASYNC);
1016 rc = fsi_master_write(master, link, id,
1017 FSI_SLAVE_BASE + FSI_LLMODE,
1018 &llmode, sizeof(llmode));
1019 if (rc)
1020 dev_warn(&master->dev,
1021 "can't set llmode on slave:%02x:%02x %d\n",
1022 link, id, rc);
1023 }
1024
1025 /* We can communicate with a slave; create the slave device and
1026 * register.
1027 */
1028 slave = kzalloc(sizeof(*slave), GFP_KERNEL);
1029 if (!slave)
1030 return -ENOMEM;
1031
1032 dev_set_name(&slave->dev, "slave@%02x:%02x", link, id);
1033 slave->dev.type = &cfam_type;
1034 slave->dev.parent = &master->dev;
1035 slave->dev.of_node = fsi_slave_find_of_node(master, link, id);
1036 slave->dev.release = fsi_slave_release;
1037 device_initialize(&slave->dev);
1038 slave->cfam_id = cfam_id;
1039 slave->master = master;
1040 slave->link = link;
1041 slave->id = id;
1042 slave->size = FSI_SLAVE_SIZE_23b;
1043 slave->t_send_delay = 16;
1044 slave->t_echo_delay = 16;
1045
1046 /* Get chip ID if any */
1047 slave->chip_id = -1;
1048 if (slave->dev.of_node) {
1049 uint32_t prop;
1050 if (!of_property_read_u32(slave->dev.of_node, "chip-id", &prop))
1051 slave->chip_id = prop;
1052
1053 }
1054
1055 rc = fsi_slave_set_smode(slave);
1056 if (rc) {
1057 dev_warn(&master->dev,
1058 "can't set smode on slave:%02x:%02x %d\n",
1059 link, id, rc);
1060 goto err_free;
1061 }
1062
1063 /* Allocate a minor in the FSI space */
1064 rc = __fsi_get_new_minor(slave, fsi_dev_cfam, &slave->dev.devt,
1065 &slave->cdev_idx);
1066 if (rc)
1067 goto err_free;
1068
1069 /* Create chardev for userspace access */
1070 cdev_init(&slave->cdev, &cfam_fops);
1071 rc = cdev_device_add(&slave->cdev, &slave->dev);
1072 if (rc) {
1073 dev_err(&slave->dev, "Error %d creating slave device\n", rc);
1074 goto err_free_ida;
1075 }
1076
1077 /* Now that we have the cdev registered with the core, any fatal
1078 * failures beyond this point will need to clean up through
1079 * cdev_device_del(). Fortunately though, nothing past here is fatal.
1080 */
1081
1082 if (master->link_config)
1083 master->link_config(master, link,
1084 slave->t_send_delay,
1085 slave->t_echo_delay);
1086
1087 /* Legacy raw file -> to be removed */
1088 rc = device_create_bin_file(&slave->dev, &fsi_slave_raw_attr);
1089 if (rc)
1090 dev_warn(&slave->dev, "failed to create raw attr: %d\n", rc);
1091
1092
1093 rc = fsi_slave_scan(slave);
1094 if (rc)
1095 dev_dbg(&master->dev, "failed during slave scan with: %d\n",
1096 rc);
1097
1098 return 0;
1099
1100 err_free_ida:
1101 fsi_free_minor(slave->dev.devt);
1102 err_free:
1103 of_node_put(slave->dev.of_node);
1104 kfree(slave);
1105 return rc;
1106 }
1107
1108 /* FSI master support */
1109 static int fsi_check_access(uint32_t addr, size_t size)
1110 {
1111 if (size == 4) {
1112 if (addr & 0x3)
1113 return -EINVAL;
1114 } else if (size == 2) {
1115 if (addr & 0x1)
1116 return -EINVAL;
1117 } else if (size != 1)
1118 return -EINVAL;
1119
1120 return 0;
1121 }
1122
1123 static int fsi_master_read(struct fsi_master *master, int link,
1124 uint8_t slave_id, uint32_t addr, void *val, size_t size)
1125 {
1126 int rc;
1127
1128 trace_fsi_master_read(master, link, slave_id, addr, size);
1129
1130 rc = fsi_check_access(addr, size);
1131 if (!rc)
1132 rc = master->read(master, link, slave_id, addr, val, size);
1133
1134 trace_fsi_master_rw_result(master, link, slave_id, addr, size,
1135 false, val, rc);
1136
1137 return rc;
1138 }
1139
1140 static int fsi_master_write(struct fsi_master *master, int link,
1141 uint8_t slave_id, uint32_t addr, const void *val, size_t size)
1142 {
1143 int rc;
1144
1145 trace_fsi_master_write(master, link, slave_id, addr, size, val);
1146
1147 rc = fsi_check_access(addr, size);
1148 if (!rc)
1149 rc = master->write(master, link, slave_id, addr, val, size);
1150
1151 trace_fsi_master_rw_result(master, link, slave_id, addr, size,
1152 true, val, rc);
1153
1154 return rc;
1155 }
1156
1157 static int fsi_master_link_enable(struct fsi_master *master, int link)
1158 {
1159 if (master->link_enable)
1160 return master->link_enable(master, link);
1161
1162 return 0;
1163 }
1164
1165 /*
1166 * Issue a break command on this link
1167 */
1168 static int fsi_master_break(struct fsi_master *master, int link)
1169 {
1170 int rc = 0;
1171
1172 trace_fsi_master_break(master, link);
1173
1174 if (master->send_break)
1175 rc = master->send_break(master, link);
1176 if (master->link_config)
1177 master->link_config(master, link, 16, 16);
1178
1179 return rc;
1180 }
1181
1182 static int fsi_master_scan(struct fsi_master *master)
1183 {
1184 int link, rc;
1185
1186 for (link = 0; link < master->n_links; link++) {
1187 rc = fsi_master_link_enable(master, link);
1188 if (rc) {
1189 dev_dbg(&master->dev,
1190 "enable link %d failed: %d\n", link, rc);
1191 continue;
1192 }
1193 rc = fsi_master_break(master, link);
1194 if (rc) {
1195 dev_dbg(&master->dev,
1196 "break to link %d failed: %d\n", link, rc);
1197 continue;
1198 }
1199
1200 fsi_slave_init(master, link, 0);
1201 }
1202
1203 return 0;
1204 }
1205
1206 static int fsi_slave_remove_device(struct device *dev, void *arg)
1207 {
1208 device_unregister(dev);
1209 return 0;
1210 }
1211
1212 static int fsi_master_remove_slave(struct device *dev, void *arg)
1213 {
1214 struct fsi_slave *slave = to_fsi_slave(dev);
1215
1216 device_for_each_child(dev, NULL, fsi_slave_remove_device);
1217 cdev_device_del(&slave->cdev, &slave->dev);
1218 put_device(dev);
1219 return 0;
1220 }
1221
1222 static void fsi_master_unscan(struct fsi_master *master)
1223 {
1224 device_for_each_child(&master->dev, NULL, fsi_master_remove_slave);
1225 }
1226
1227 int fsi_master_rescan(struct fsi_master *master)
1228 {
1229 int rc;
1230
1231 mutex_lock(&master->scan_lock);
1232 fsi_master_unscan(master);
1233 rc = fsi_master_scan(master);
1234 mutex_unlock(&master->scan_lock);
1235
1236 return rc;
1237 }
1238 EXPORT_SYMBOL_GPL(fsi_master_rescan);
1239
1240 static ssize_t master_rescan_store(struct device *dev,
1241 struct device_attribute *attr, const char *buf, size_t count)
1242 {
1243 struct fsi_master *master = to_fsi_master(dev);
1244 int rc;
1245
1246 rc = fsi_master_rescan(master);
1247 if (rc < 0)
1248 return rc;
1249
1250 return count;
1251 }
1252
1253 static DEVICE_ATTR(rescan, 0200, NULL, master_rescan_store);
1254
1255 static ssize_t master_break_store(struct device *dev,
1256 struct device_attribute *attr, const char *buf, size_t count)
1257 {
1258 struct fsi_master *master = to_fsi_master(dev);
1259
1260 fsi_master_break(master, 0);
1261
1262 return count;
1263 }
1264
1265 static DEVICE_ATTR(break, 0200, NULL, master_break_store);
1266
1267 static struct attribute *master_attrs[] = {
1268 &dev_attr_break.attr,
1269 &dev_attr_rescan.attr,
1270 NULL
1271 };
1272
1273 ATTRIBUTE_GROUPS(master);
1274
1275 static struct class fsi_master_class = {
1276 .name = "fsi-master",
1277 .dev_groups = master_groups,
1278 };
1279
1280 int fsi_master_register(struct fsi_master *master)
1281 {
1282 int rc;
1283 struct device_node *np;
1284
1285 mutex_init(&master->scan_lock);
1286 master->idx = ida_simple_get(&master_ida, 0, INT_MAX, GFP_KERNEL);
1287 dev_set_name(&master->dev, "fsi%d", master->idx);
1288 master->dev.class = &fsi_master_class;
1289
1290 rc = device_register(&master->dev);
1291 if (rc) {
1292 ida_simple_remove(&master_ida, master->idx);
1293 return rc;
1294 }
1295
1296 np = dev_of_node(&master->dev);
1297 if (!of_property_read_bool(np, "no-scan-on-init")) {
1298 mutex_lock(&master->scan_lock);
1299 fsi_master_scan(master);
1300 mutex_unlock(&master->scan_lock);
1301 }
1302
1303 return 0;
1304 }
1305 EXPORT_SYMBOL_GPL(fsi_master_register);
1306
1307 void fsi_master_unregister(struct fsi_master *master)
1308 {
1309 if (master->idx >= 0) {
1310 ida_simple_remove(&master_ida, master->idx);
1311 master->idx = -1;
1312 }
1313
1314 mutex_lock(&master->scan_lock);
1315 fsi_master_unscan(master);
1316 mutex_unlock(&master->scan_lock);
1317 device_unregister(&master->dev);
1318 }
1319 EXPORT_SYMBOL_GPL(fsi_master_unregister);
1320
1321 /* FSI core & Linux bus type definitions */
1322
1323 static int fsi_bus_match(struct device *dev, struct device_driver *drv)
1324 {
1325 struct fsi_device *fsi_dev = to_fsi_dev(dev);
1326 struct fsi_driver *fsi_drv = to_fsi_drv(drv);
1327 const struct fsi_device_id *id;
1328
1329 if (!fsi_drv->id_table)
1330 return 0;
1331
1332 for (id = fsi_drv->id_table; id->engine_type; id++) {
1333 if (id->engine_type != fsi_dev->engine_type)
1334 continue;
1335 if (id->version == FSI_VERSION_ANY ||
1336 id->version == fsi_dev->version)
1337 return 1;
1338 }
1339
1340 return 0;
1341 }
1342
1343 int fsi_driver_register(struct fsi_driver *fsi_drv)
1344 {
1345 if (!fsi_drv)
1346 return -EINVAL;
1347 if (!fsi_drv->id_table)
1348 return -EINVAL;
1349
1350 return driver_register(&fsi_drv->drv);
1351 }
1352 EXPORT_SYMBOL_GPL(fsi_driver_register);
1353
1354 void fsi_driver_unregister(struct fsi_driver *fsi_drv)
1355 {
1356 driver_unregister(&fsi_drv->drv);
1357 }
1358 EXPORT_SYMBOL_GPL(fsi_driver_unregister);
1359
1360 struct bus_type fsi_bus_type = {
1361 .name = "fsi",
1362 .match = fsi_bus_match,
1363 };
1364 EXPORT_SYMBOL_GPL(fsi_bus_type);
1365
1366 static int __init fsi_init(void)
1367 {
1368 int rc;
1369
1370 rc = alloc_chrdev_region(&fsi_base_dev, 0, FSI_CHAR_MAX_DEVICES, "fsi");
1371 if (rc)
1372 return rc;
1373 rc = bus_register(&fsi_bus_type);
1374 if (rc)
1375 goto fail_bus;
1376
1377 rc = class_register(&fsi_master_class);
1378 if (rc)
1379 goto fail_class;
1380
1381 return 0;
1382
1383 fail_class:
1384 bus_unregister(&fsi_bus_type);
1385 fail_bus:
1386 unregister_chrdev_region(fsi_base_dev, FSI_CHAR_MAX_DEVICES);
1387 return rc;
1388 }
1389 postcore_initcall(fsi_init);
1390
1391 static void fsi_exit(void)
1392 {
1393 class_unregister(&fsi_master_class);
1394 bus_unregister(&fsi_bus_type);
1395 unregister_chrdev_region(fsi_base_dev, FSI_CHAR_MAX_DEVICES);
1396 ida_destroy(&fsi_minor_ida);
1397 }
1398 module_exit(fsi_exit);
1399 module_param(discard_errors, int, 0664);
1400 MODULE_LICENSE("GPL");
1401 MODULE_PARM_DESC(discard_errors, "Don't invoke error handling on bus accesses");
Linux with added FPC-III support