1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/device.h>
4 #include <linux/err.h>
5 #include <linux/errno.h>
6 #include <linux/fs.h>
7 #include <linux/fsi-sbefifo.h>
8 #include <linux/gfp.h>
9 #include <linux/idr.h>
10 #include <linux/kernel.h>
11 #include <linux/list.h>
12 #include <linux/miscdevice.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/fsi-occ.h>
16 #include <linux/of.h>
17 #include <linux/platform_device.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/uaccess.h>
21 #include <asm/unaligned.h>
22
23 #define OCC_SRAM_BYTES 4096
24 #define OCC_CMD_DATA_BYTES 4090
25 #define OCC_RESP_DATA_BYTES 4089
26
27 #define OCC_SRAM_CMD_ADDR 0xFFFBE000
28 #define OCC_SRAM_RSP_ADDR 0xFFFBF000
29
30 /*
31 * Assume we don't have much FFDC, if we do we'll overflow and
32 * fail the command. This needs to be big enough for simple
33 * commands as well.
34 */
35 #define OCC_SBE_STATUS_WORDS 32
36
37 #define OCC_TIMEOUT_MS 1000
38 #define OCC_CMD_IN_PRG_WAIT_MS 50
39
40 struct occ {
41 struct device *dev;
42 struct device *sbefifo;
43 char name[32];
44 int idx;
45 struct miscdevice mdev;
46 struct mutex occ_lock;
47 };
48
49 #define to_occ(x) container_of((x), struct occ, mdev)
50
51 struct occ_response {
52 u8 seq_no;
53 u8 cmd_type;
54 u8 return_status;
55 __be16 data_length;
56 u8 data[OCC_RESP_DATA_BYTES + 2]; /* two bytes checksum */
57 } __packed;
58
59 struct occ_client {
60 struct occ *occ;
61 struct mutex lock;
62 size_t data_size;
63 size_t read_offset;
64 u8 *buffer;
65 };
66
67 #define to_client(x) container_of((x), struct occ_client, xfr)
68
69 static DEFINE_IDA(occ_ida);
70
occ_open(struct inode * inode,struct file * file)71 static int occ_open(struct inode *inode, struct file *file)
72 {
73 struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL);
74 struct miscdevice *mdev = file->private_data;
75 struct occ *occ = to_occ(mdev);
76
77 if (!client)
78 return -ENOMEM;
79
80 client->buffer = (u8 *)__get_free_page(GFP_KERNEL);
81 if (!client->buffer) {
82 kfree(client);
83 return -ENOMEM;
84 }
85
86 client->occ = occ;
87 mutex_init(&client->lock);
88 file->private_data = client;
89
90 /* We allocate a 1-page buffer, make sure it all fits */
91 BUILD_BUG_ON((OCC_CMD_DATA_BYTES + 3) > PAGE_SIZE);
92 BUILD_BUG_ON((OCC_RESP_DATA_BYTES + 7) > PAGE_SIZE);
93
94 return 0;
95 }
96
occ_read(struct file * file,char __user * buf,size_t len,loff_t * offset)97 static ssize_t occ_read(struct file *file, char __user *buf, size_t len,
98 loff_t *offset)
99 {
100 struct occ_client *client = file->private_data;
101 ssize_t rc = 0;
102
103 if (!client)
104 return -ENODEV;
105
106 if (len > OCC_SRAM_BYTES)
107 return -EINVAL;
108
109 mutex_lock(&client->lock);
110
111 /* This should not be possible ... */
112 if (WARN_ON_ONCE(client->read_offset > client->data_size)) {
113 rc = -EIO;
114 goto done;
115 }
116
117 /* Grab how much data we have to read */
118 rc = min(len, client->data_size - client->read_offset);
119 if (copy_to_user(buf, client->buffer + client->read_offset, rc))
120 rc = -EFAULT;
121 else
122 client->read_offset += rc;
123
124 done:
125 mutex_unlock(&client->lock);
126
127 return rc;
128 }
129
occ_write(struct file * file,const char __user * buf,size_t len,loff_t * offset)130 static ssize_t occ_write(struct file *file, const char __user *buf,
131 size_t len, loff_t *offset)
132 {
133 struct occ_client *client = file->private_data;
134 size_t rlen, data_length;
135 u16 checksum = 0;
136 ssize_t rc, i;
137 u8 *cmd;
138
139 if (!client)
140 return -ENODEV;
141
142 if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3)
143 return -EINVAL;
144
145 mutex_lock(&client->lock);
146
147 /* Construct the command */
148 cmd = client->buffer;
149
150 /* Sequence number (we could increment and compare with response) */
151 cmd[0] = 1;
152
153 /*
154 * Copy the user command (assume user data follows the occ command
155 * format)
156 * byte 0: command type
157 * bytes 1-2: data length (msb first)
158 * bytes 3-n: data
159 */
160 if (copy_from_user(&cmd[1], buf, len)) {
161 rc = -EFAULT;
162 goto done;
163 }
164
165 /* Extract data length */
166 data_length = (cmd[2] << 8) + cmd[3];
167 if (data_length > OCC_CMD_DATA_BYTES) {
168 rc = -EINVAL;
169 goto done;
170 }
171
172 /* Calculate checksum */
173 for (i = 0; i < data_length + 4; ++i)
174 checksum += cmd[i];
175
176 cmd[data_length + 4] = checksum >> 8;
177 cmd[data_length + 5] = checksum & 0xFF;
178
179 /* Submit command */
180 rlen = PAGE_SIZE;
181 rc = fsi_occ_submit(client->occ->dev, cmd, data_length + 6, cmd,
182 &rlen);
183 if (rc)
184 goto done;
185
186 /* Set read tracking data */
187 client->data_size = rlen;
188 client->read_offset = 0;
189
190 /* Done */
191 rc = len;
192
193 done:
194 mutex_unlock(&client->lock);
195
196 return rc;
197 }
198
occ_release(struct inode * inode,struct file * file)199 static int occ_release(struct inode *inode, struct file *file)
200 {
201 struct occ_client *client = file->private_data;
202
203 free_page((unsigned long)client->buffer);
204 kfree(client);
205
206 return 0;
207 }
208
209 static const struct file_operations occ_fops = {
210 .owner = THIS_MODULE,
211 .open = occ_open,
212 .read = occ_read,
213 .write = occ_write,
214 .release = occ_release,
215 };
216
occ_verify_checksum(struct occ_response * resp,u16 data_length)217 static int occ_verify_checksum(struct occ_response *resp, u16 data_length)
218 {
219 /* Fetch the two bytes after the data for the checksum. */
220 u16 checksum_resp = get_unaligned_be16(&resp->data[data_length]);
221 u16 checksum;
222 u16 i;
223
224 checksum = resp->seq_no;
225 checksum += resp->cmd_type;
226 checksum += resp->return_status;
227 checksum += (data_length >> 8) + (data_length & 0xFF);
228
229 for (i = 0; i < data_length; ++i)
230 checksum += resp->data[i];
231
232 if (checksum != checksum_resp)
233 return -EBADMSG;
234
235 return 0;
236 }
237
occ_getsram(struct occ * occ,u32 address,void * data,ssize_t len)238 static int occ_getsram(struct occ *occ, u32 address, void *data, ssize_t len)
239 {
240 u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */
241 size_t resp_len, resp_data_len;
242 __be32 *resp, cmd[5];
243 int rc;
244
245 /*
246 * Magic sequence to do SBE getsram command. SBE will fetch data from
247 * specified SRAM address.
248 */
249 cmd[0] = cpu_to_be32(0x5);
250 cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_OCC_SRAM);
251 cmd[2] = cpu_to_be32(1);
252 cmd[3] = cpu_to_be32(address);
253 cmd[4] = cpu_to_be32(data_len);
254
255 resp_len = (data_len >> 2) + OCC_SBE_STATUS_WORDS;
256 resp = kzalloc(resp_len << 2, GFP_KERNEL);
257 if (!resp)
258 return -ENOMEM;
259
260 rc = sbefifo_submit(occ->sbefifo, cmd, 5, resp, &resp_len);
261 if (rc)
262 goto free;
263
264 rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_GET_OCC_SRAM,
265 resp, resp_len, &resp_len);
266 if (rc)
267 goto free;
268
269 resp_data_len = be32_to_cpu(resp[resp_len - 1]);
270 if (resp_data_len != data_len) {
271 dev_err(occ->dev, "SRAM read expected %d bytes got %zd\n",
272 data_len, resp_data_len);
273 rc = -EBADMSG;
274 } else {
275 memcpy(data, resp, len);
276 }
277
278 free:
279 /* Convert positive SBEI status */
280 if (rc > 0) {
281 dev_err(occ->dev, "SRAM read returned failure status: %08x\n",
282 rc);
283 rc = -EBADMSG;
284 }
285
286 kfree(resp);
287 return rc;
288 }
289
occ_putsram(struct occ * occ,u32 address,const void * data,ssize_t len)290 static int occ_putsram(struct occ *occ, u32 address, const void *data,
291 ssize_t len)
292 {
293 size_t cmd_len, buf_len, resp_len, resp_data_len;
294 u32 data_len = ((len + 7) / 8) * 8; /* must be multiples of 8 B */
295 __be32 *buf;
296 int rc;
297
298 /*
299 * We use the same buffer for command and response, make
300 * sure it's big enough
301 */
302 resp_len = OCC_SBE_STATUS_WORDS;
303 cmd_len = (data_len >> 2) + 5;
304 buf_len = max(cmd_len, resp_len);
305 buf = kzalloc(buf_len << 2, GFP_KERNEL);
306 if (!buf)
307 return -ENOMEM;
308
309 /*
310 * Magic sequence to do SBE putsram command. SBE will transfer
311 * data to specified SRAM address.
312 */
313 buf[0] = cpu_to_be32(cmd_len);
314 buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
315 buf[2] = cpu_to_be32(1);
316 buf[3] = cpu_to_be32(address);
317 buf[4] = cpu_to_be32(data_len);
318
319 memcpy(&buf[5], data, len);
320
321 rc = sbefifo_submit(occ->sbefifo, buf, cmd_len, buf, &resp_len);
322 if (rc)
323 goto free;
324
325 rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
326 buf, resp_len, &resp_len);
327 if (rc)
328 goto free;
329
330 if (resp_len != 1) {
331 dev_err(occ->dev, "SRAM write response length invalid: %zd\n",
332 resp_len);
333 rc = -EBADMSG;
334 } else {
335 resp_data_len = be32_to_cpu(buf[0]);
336 if (resp_data_len != data_len) {
337 dev_err(occ->dev,
338 "SRAM write expected %d bytes got %zd\n",
339 data_len, resp_data_len);
340 rc = -EBADMSG;
341 }
342 }
343
344 free:
345 /* Convert positive SBEI status */
346 if (rc > 0) {
347 dev_err(occ->dev, "SRAM write returned failure status: %08x\n",
348 rc);
349 rc = -EBADMSG;
350 }
351
352 kfree(buf);
353 return rc;
354 }
355
occ_trigger_attn(struct occ * occ)356 static int occ_trigger_attn(struct occ *occ)
357 {
358 __be32 buf[OCC_SBE_STATUS_WORDS];
359 size_t resp_len, resp_data_len;
360 int rc;
361
362 BUILD_BUG_ON(OCC_SBE_STATUS_WORDS < 7);
363 resp_len = OCC_SBE_STATUS_WORDS;
364
365 buf[0] = cpu_to_be32(0x5 + 0x2); /* Chip-op length in words */
366 buf[1] = cpu_to_be32(SBEFIFO_CMD_PUT_OCC_SRAM);
367 buf[2] = cpu_to_be32(0x3); /* Mode: Circular */
368 buf[3] = cpu_to_be32(0x0); /* Address: ignore in mode 3 */
369 buf[4] = cpu_to_be32(0x8); /* Data length in bytes */
370 buf[5] = cpu_to_be32(0x20010000); /* Trigger OCC attention */
371 buf[6] = 0;
372
373 rc = sbefifo_submit(occ->sbefifo, buf, 7, buf, &resp_len);
374 if (rc)
375 goto error;
376
377 rc = sbefifo_parse_status(occ->sbefifo, SBEFIFO_CMD_PUT_OCC_SRAM,
378 buf, resp_len, &resp_len);
379 if (rc)
380 goto error;
381
382 if (resp_len != 1) {
383 dev_err(occ->dev, "SRAM attn response length invalid: %zd\n",
384 resp_len);
385 rc = -EBADMSG;
386 } else {
387 resp_data_len = be32_to_cpu(buf[0]);
388 if (resp_data_len != 8) {
389 dev_err(occ->dev,
390 "SRAM attn expected 8 bytes got %zd\n",
391 resp_data_len);
392 rc = -EBADMSG;
393 }
394 }
395
396 error:
397 /* Convert positive SBEI status */
398 if (rc > 0) {
399 dev_err(occ->dev, "SRAM attn returned failure status: %08x\n",
400 rc);
401 rc = -EBADMSG;
402 }
403
404 return rc;
405 }
406
fsi_occ_submit(struct device * dev,const void * request,size_t req_len,void * response,size_t * resp_len)407 int fsi_occ_submit(struct device *dev, const void *request, size_t req_len,
408 void *response, size_t *resp_len)
409 {
410 const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
411 const unsigned long wait_time =
412 msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
413 struct occ *occ = dev_get_drvdata(dev);
414 struct occ_response *resp = response;
415 u8 seq_no;
416 u16 resp_data_length;
417 unsigned long start;
418 int rc;
419
420 if (!occ)
421 return -ENODEV;
422
423 if (*resp_len < 7) {
424 dev_dbg(dev, "Bad resplen %zd\n", *resp_len);
425 return -EINVAL;
426 }
427
428 mutex_lock(&occ->occ_lock);
429
430 /* Extract the seq_no from the command (first byte) */
431 seq_no = *(const u8 *)request;
432 rc = occ_putsram(occ, OCC_SRAM_CMD_ADDR, request, req_len);
433 if (rc)
434 goto done;
435
436 rc = occ_trigger_attn(occ);
437 if (rc)
438 goto done;
439
440 /* Read occ response header */
441 start = jiffies;
442 do {
443 rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR, resp, 8);
444 if (rc)
445 goto done;
446
447 if (resp->return_status == OCC_RESP_CMD_IN_PRG ||
448 resp->return_status == OCC_RESP_CRIT_INIT ||
449 resp->seq_no != seq_no) {
450 rc = -ETIMEDOUT;
451
452 if (time_after(jiffies, start + timeout)) {
453 dev_err(occ->dev, "resp timeout status=%02x "
454 "resp seq_no=%d our seq_no=%d\n",
455 resp->return_status, resp->seq_no,
456 seq_no);
457 goto done;
458 }
459
460 set_current_state(TASK_UNINTERRUPTIBLE);
461 schedule_timeout(wait_time);
462 }
463 } while (rc);
464
465 /* Extract size of response data */
466 resp_data_length = get_unaligned_be16(&resp->data_length);
467
468 /* Message size is data length + 5 bytes header + 2 bytes checksum */
469 if ((resp_data_length + 7) > *resp_len) {
470 rc = -EMSGSIZE;
471 goto done;
472 }
473
474 dev_dbg(dev, "resp_status=%02x resp_data_len=%d\n",
475 resp->return_status, resp_data_length);
476
477 /* Grab the rest */
478 if (resp_data_length > 1) {
479 /* already got 3 bytes resp, also need 2 bytes checksum */
480 rc = occ_getsram(occ, OCC_SRAM_RSP_ADDR + 8,
481 &resp->data[3], resp_data_length - 1);
482 if (rc)
483 goto done;
484 }
485
486 *resp_len = resp_data_length + 7;
487 rc = occ_verify_checksum(resp, resp_data_length);
488
489 done:
490 mutex_unlock(&occ->occ_lock);
491
492 return rc;
493 }
494 EXPORT_SYMBOL_GPL(fsi_occ_submit);
495
occ_unregister_child(struct device * dev,void * data)496 static int occ_unregister_child(struct device *dev, void *data)
497 {
498 struct platform_device *hwmon_dev = to_platform_device(dev);
499
500 platform_device_unregister(hwmon_dev);
501
502 return 0;
503 }
504
occ_probe(struct platform_device * pdev)505 static int occ_probe(struct platform_device *pdev)
506 {
507 int rc;
508 u32 reg;
509 struct occ *occ;
510 struct platform_device *hwmon_dev;
511 struct device *dev = &pdev->dev;
512 struct platform_device_info hwmon_dev_info = {
513 .parent = dev,
514 .name = "occ-hwmon",
515 };
516
517 occ = devm_kzalloc(dev, sizeof(*occ), GFP_KERNEL);
518 if (!occ)
519 return -ENOMEM;
520
521 occ->dev = dev;
522 occ->sbefifo = dev->parent;
523 mutex_init(&occ->occ_lock);
524
525 if (dev->of_node) {
526 rc = of_property_read_u32(dev->of_node, "reg", ®);
527 if (!rc) {
528 /* make sure we don't have a duplicate from dts */
529 occ->idx = ida_simple_get(&occ_ida, reg, reg + 1,
530 GFP_KERNEL);
531 if (occ->idx < 0)
532 occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
533 GFP_KERNEL);
534 } else {
535 occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX,
536 GFP_KERNEL);
537 }
538 } else {
539 occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL);
540 }
541
542 platform_set_drvdata(pdev, occ);
543
544 snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx);
545 occ->mdev.fops = &occ_fops;
546 occ->mdev.minor = MISC_DYNAMIC_MINOR;
547 occ->mdev.name = occ->name;
548 occ->mdev.parent = dev;
549
550 rc = misc_register(&occ->mdev);
551 if (rc) {
552 dev_err(dev, "failed to register miscdevice: %d\n", rc);
553 ida_simple_remove(&occ_ida, occ->idx);
554 return rc;
555 }
556
557 hwmon_dev_info.id = occ->idx;
558 hwmon_dev = platform_device_register_full(&hwmon_dev_info);
559 if (IS_ERR(hwmon_dev))
560 dev_warn(dev, "failed to create hwmon device\n");
561
562 return 0;
563 }
564
occ_remove(struct platform_device * pdev)565 static int occ_remove(struct platform_device *pdev)
566 {
567 struct occ *occ = platform_get_drvdata(pdev);
568
569 misc_deregister(&occ->mdev);
570
571 device_for_each_child(&pdev->dev, NULL, occ_unregister_child);
572
573 ida_simple_remove(&occ_ida, occ->idx);
574
575 return 0;
576 }
577
578 static const struct of_device_id occ_match[] = {
579 { .compatible = "ibm,p9-occ" },
580 { },
581 };
582 MODULE_DEVICE_TABLE(of, occ_match);
583
584 static struct platform_driver occ_driver = {
585 .driver = {
586 .name = "occ",
587 .of_match_table = occ_match,
588 },
589 .probe = occ_probe,
590 .remove = occ_remove,
591 };
592
occ_init(void)593 static int occ_init(void)
594 {
595 return platform_driver_register(&occ_driver);
596 }
597
occ_exit(void)598 static void occ_exit(void)
599 {
600 platform_driver_unregister(&occ_driver);
601
602 ida_destroy(&occ_ida);
603 }
604
605 module_init(occ_init);
606 module_exit(occ_exit);
607
608 MODULE_AUTHOR("Eddie James <eajames@linux.ibm.com>");
609 MODULE_DESCRIPTION("BMC P9 OCC driver");
610 MODULE_LICENSE("GPL");
611