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1// SPDX-License-Identifier: (GPL-2.0 OR MIT)
2/*
3 * Siemens System Memory Buffer driver.
4 * Copyright(c) 2022, HiSilicon Limited.
5 */
6
7#include <linux/atomic.h>
8#include <linux/acpi.h>
9#include <linux/circ_buf.h>
10#include <linux/err.h>
11#include <linux/fs.h>
12#include <linux/module.h>
13#include <linux/mod_devicetable.h>
14#include <linux/platform_device.h>
15
16#include "coresight-etm-perf.h"
17#include "coresight-priv.h"
18#include "ultrasoc-smb.h"
19
20DEFINE_CORESIGHT_DEVLIST(sink_devs, "ultra_smb");
21
22#define ULTRASOC_SMB_DSM_UUID "82ae1283-7f6a-4cbe-aa06-53e8fb24db18"
23
24static bool smb_buffer_not_empty(struct smb_drv_data *drvdata)
25{
26 u32 buf_status = readl(drvdata->base + SMB_LB_INT_STS_REG);
27
28 return FIELD_GET(SMB_LB_INT_STS_NOT_EMPTY_MSK, buf_status);
29}
30
31static void smb_update_data_size(struct smb_drv_data *drvdata)
32{
33 struct smb_data_buffer *sdb = &drvdata->sdb;
34 u32 buf_wrptr;
35
36 buf_wrptr = readl(drvdata->base + SMB_LB_WR_ADDR_REG) -
37 sdb->buf_hw_base;
38
39 /* Buffer is full */
40 if (buf_wrptr == sdb->buf_rdptr && smb_buffer_not_empty(drvdata)) {
41 sdb->data_size = sdb->buf_size;
42 return;
43 }
44
45 /* The buffer mode is circular buffer mode */
46 sdb->data_size = CIRC_CNT(buf_wrptr, sdb->buf_rdptr,
47 sdb->buf_size);
48}
49
50/*
51 * The read pointer adds @nbytes bytes (may round up to the beginning)
52 * after the data is read or discarded, while needing to update the
53 * available data size.
54 */
55static void smb_update_read_ptr(struct smb_drv_data *drvdata, u32 nbytes)
56{
57 struct smb_data_buffer *sdb = &drvdata->sdb;
58
59 sdb->buf_rdptr += nbytes;
60 sdb->buf_rdptr %= sdb->buf_size;
61 writel(sdb->buf_hw_base + sdb->buf_rdptr,
62 drvdata->base + SMB_LB_RD_ADDR_REG);
63
64 sdb->data_size -= nbytes;
65}
66
67static void smb_reset_buffer(struct smb_drv_data *drvdata)
68{
69 struct smb_data_buffer *sdb = &drvdata->sdb;
70 u32 write_ptr;
71
72 /*
73 * We must flush and discard any data left in hardware path
74 * to avoid corrupting the next session.
75 * Note: The write pointer will never exceed the read pointer.
76 */
77 writel(SMB_LB_PURGE_PURGED, drvdata->base + SMB_LB_PURGE_REG);
78
79 /* Reset SMB logical buffer status flags */
80 writel(SMB_LB_INT_STS_RESET, drvdata->base + SMB_LB_INT_STS_REG);
81
82 write_ptr = readl(drvdata->base + SMB_LB_WR_ADDR_REG);
83
84 /* Do nothing, not data left in hardware path */
85 if (!write_ptr || write_ptr == sdb->buf_rdptr + sdb->buf_hw_base)
86 return;
87
88 /*
89 * The SMB_LB_WR_ADDR_REG register is read-only,
90 * Synchronize the read pointer to write pointer.
91 */
92 writel(write_ptr, drvdata->base + SMB_LB_RD_ADDR_REG);
93 sdb->buf_rdptr = write_ptr - sdb->buf_hw_base;
94}
95
96static int smb_open(struct inode *inode, struct file *file)
97{
98 struct smb_drv_data *drvdata = container_of(file->private_data,
99 struct smb_drv_data, miscdev);
100
101 guard(spinlock)(&drvdata->spinlock);
102
103 if (drvdata->reading)
104 return -EBUSY;
105
106 if (drvdata->csdev->refcnt)
107 return -EBUSY;
108
109 smb_update_data_size(drvdata);
110 drvdata->reading = true;
111
112 return 0;
113}
114
115static ssize_t smb_read(struct file *file, char __user *data, size_t len,
116 loff_t *ppos)
117{
118 struct smb_drv_data *drvdata = container_of(file->private_data,
119 struct smb_drv_data, miscdev);
120 struct smb_data_buffer *sdb = &drvdata->sdb;
121 struct device *dev = &drvdata->csdev->dev;
122 ssize_t to_copy = 0;
123
124 if (!len)
125 return 0;
126
127 if (!sdb->data_size)
128 return 0;
129
130 to_copy = min(sdb->data_size, len);
131
132 /* Copy parts of trace data when read pointer wrap around SMB buffer */
133 if (sdb->buf_rdptr + to_copy > sdb->buf_size)
134 to_copy = sdb->buf_size - sdb->buf_rdptr;
135
136 if (copy_to_user(data, sdb->buf_base + sdb->buf_rdptr, to_copy)) {
137 dev_dbg(dev, "Failed to copy data to user\n");
138 return -EFAULT;
139 }
140
141 *ppos += to_copy;
142 smb_update_read_ptr(drvdata, to_copy);
143 if (!sdb->data_size)
144 smb_reset_buffer(drvdata);
145
146 dev_dbg(dev, "%zu bytes copied\n", to_copy);
147 return to_copy;
148}
149
150static int smb_release(struct inode *inode, struct file *file)
151{
152 struct smb_drv_data *drvdata = container_of(file->private_data,
153 struct smb_drv_data, miscdev);
154
155 guard(spinlock)(&drvdata->spinlock);
156 drvdata->reading = false;
157
158 return 0;
159}
160
161static const struct file_operations smb_fops = {
162 .owner = THIS_MODULE,
163 .open = smb_open,
164 .read = smb_read,
165 .release = smb_release,
166};
167
168static ssize_t buf_size_show(struct device *dev, struct device_attribute *attr,
169 char *buf)
170{
171 struct smb_drv_data *drvdata = dev_get_drvdata(dev->parent);
172
173 return sysfs_emit(buf, "0x%lx\n", drvdata->sdb.buf_size);
174}
175static DEVICE_ATTR_RO(buf_size);
176
177static struct attribute *smb_sink_attrs[] = {
178 coresight_simple_reg32(read_pos, SMB_LB_RD_ADDR_REG),
179 coresight_simple_reg32(write_pos, SMB_LB_WR_ADDR_REG),
180 coresight_simple_reg32(buf_status, SMB_LB_INT_STS_REG),
181 &dev_attr_buf_size.attr,
182 NULL
183};
184
185static const struct attribute_group smb_sink_group = {
186 .attrs = smb_sink_attrs,
187 .name = "mgmt",
188};
189
190static const struct attribute_group *smb_sink_groups[] = {
191 &smb_sink_group,
192 NULL
193};
194
195static void smb_enable_hw(struct smb_drv_data *drvdata)
196{
197 writel(SMB_GLB_EN_HW_ENABLE, drvdata->base + SMB_GLB_EN_REG);
198}
199
200static void smb_disable_hw(struct smb_drv_data *drvdata)
201{
202 writel(0x0, drvdata->base + SMB_GLB_EN_REG);
203}
204
205static void smb_enable_sysfs(struct coresight_device *csdev)
206{
207 struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
208
209 if (coresight_get_mode(csdev) != CS_MODE_DISABLED)
210 return;
211
212 smb_enable_hw(drvdata);
213 coresight_set_mode(csdev, CS_MODE_SYSFS);
214}
215
216static int smb_enable_perf(struct coresight_device *csdev, void *data)
217{
218 struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
219 struct perf_output_handle *handle = data;
220 struct cs_buffers *buf = etm_perf_sink_config(handle);
221 pid_t pid;
222
223 if (!buf)
224 return -EINVAL;
225
226 /* Get a handle on the pid of the target process */
227 pid = buf->pid;
228
229 /* Device is already in used by other session */
230 if (drvdata->pid != -1 && drvdata->pid != pid)
231 return -EBUSY;
232
233 if (drvdata->pid == -1) {
234 smb_enable_hw(drvdata);
235 drvdata->pid = pid;
236 coresight_set_mode(csdev, CS_MODE_PERF);
237 }
238
239 return 0;
240}
241
242static int smb_enable(struct coresight_device *csdev, enum cs_mode mode,
243 void *data)
244{
245 struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
246 int ret = 0;
247
248 guard(spinlock)(&drvdata->spinlock);
249
250 /* Do nothing, the trace data is reading by other interface now */
251 if (drvdata->reading)
252 return -EBUSY;
253
254 /* Do nothing, the SMB is already enabled as other mode */
255 if (coresight_get_mode(csdev) != CS_MODE_DISABLED &&
256 coresight_get_mode(csdev) != mode)
257 return -EBUSY;
258
259 switch (mode) {
260 case CS_MODE_SYSFS:
261 smb_enable_sysfs(csdev);
262 break;
263 case CS_MODE_PERF:
264 ret = smb_enable_perf(csdev, data);
265 break;
266 default:
267 ret = -EINVAL;
268 }
269
270 if (ret)
271 return ret;
272
273 csdev->refcnt++;
274 dev_dbg(&csdev->dev, "Ultrasoc SMB enabled\n");
275
276 return ret;
277}
278
279static int smb_disable(struct coresight_device *csdev)
280{
281 struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
282
283 guard(spinlock)(&drvdata->spinlock);
284
285 if (drvdata->reading)
286 return -EBUSY;
287
288 csdev->refcnt--;
289 if (csdev->refcnt)
290 return -EBUSY;
291
292 /* Complain if we (somehow) got out of sync */
293 WARN_ON_ONCE(coresight_get_mode(csdev) == CS_MODE_DISABLED);
294
295 smb_disable_hw(drvdata);
296
297 /* Dissociate from the target process. */
298 drvdata->pid = -1;
299 coresight_set_mode(csdev, CS_MODE_DISABLED);
300 dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n");
301
302 return 0;
303}
304
305static void *smb_alloc_buffer(struct coresight_device *csdev,
306 struct perf_event *event, void **pages,
307 int nr_pages, bool overwrite)
308{
309 struct cs_buffers *buf;
310 int node;
311
312 node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
313 buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
314 if (!buf)
315 return NULL;
316
317 buf->snapshot = overwrite;
318 buf->nr_pages = nr_pages;
319 buf->data_pages = pages;
320 buf->pid = task_pid_nr(event->owner);
321
322 return buf;
323}
324
325static void smb_free_buffer(void *config)
326{
327 struct cs_buffers *buf = config;
328
329 kfree(buf);
330}
331
332static void smb_sync_perf_buffer(struct smb_drv_data *drvdata,
333 struct cs_buffers *buf,
334 unsigned long head)
335{
336 struct smb_data_buffer *sdb = &drvdata->sdb;
337 char **dst_pages = (char **)buf->data_pages;
338 unsigned long to_copy;
339 long pg_idx, pg_offset;
340
341 pg_idx = head >> PAGE_SHIFT;
342 pg_offset = head & (PAGE_SIZE - 1);
343
344 while (sdb->data_size) {
345 unsigned long pg_space = PAGE_SIZE - pg_offset;
346
347 to_copy = min(sdb->data_size, pg_space);
348
349 /* Copy parts of trace data when read pointer wrap around */
350 if (sdb->buf_rdptr + to_copy > sdb->buf_size)
351 to_copy = sdb->buf_size - sdb->buf_rdptr;
352
353 memcpy(dst_pages[pg_idx] + pg_offset,
354 sdb->buf_base + sdb->buf_rdptr, to_copy);
355
356 pg_offset += to_copy;
357 if (pg_offset >= PAGE_SIZE) {
358 pg_offset = 0;
359 pg_idx++;
360 pg_idx %= buf->nr_pages;
361 }
362 smb_update_read_ptr(drvdata, to_copy);
363 }
364
365 smb_reset_buffer(drvdata);
366}
367
368static unsigned long smb_update_buffer(struct coresight_device *csdev,
369 struct perf_output_handle *handle,
370 void *sink_config)
371{
372 struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
373 struct smb_data_buffer *sdb = &drvdata->sdb;
374 struct cs_buffers *buf = sink_config;
375 unsigned long data_size;
376 bool lost = false;
377
378 if (!buf)
379 return 0;
380
381 guard(spinlock)(&drvdata->spinlock);
382
383 /* Don't do anything if another tracer is using this sink. */
384 if (csdev->refcnt != 1)
385 return 0;
386
387 smb_disable_hw(drvdata);
388 smb_update_data_size(drvdata);
389
390 /*
391 * The SMB buffer may be bigger than the space available in the
392 * perf ring buffer (handle->size). If so advance the offset so
393 * that we get the latest trace data.
394 */
395 if (sdb->data_size > handle->size) {
396 smb_update_read_ptr(drvdata, sdb->data_size - handle->size);
397 lost = true;
398 }
399
400 data_size = sdb->data_size;
401 smb_sync_perf_buffer(drvdata, buf, handle->head);
402 if (!buf->snapshot && lost)
403 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
404
405 return data_size;
406}
407
408static const struct coresight_ops_sink smb_cs_ops = {
409 .enable = smb_enable,
410 .disable = smb_disable,
411 .alloc_buffer = smb_alloc_buffer,
412 .free_buffer = smb_free_buffer,
413 .update_buffer = smb_update_buffer,
414};
415
416static const struct coresight_ops cs_ops = {
417 .sink_ops = &smb_cs_ops,
418};
419
420static int smb_init_data_buffer(struct platform_device *pdev,
421 struct smb_data_buffer *sdb)
422{
423 struct resource *res;
424 void *base;
425
426 res = platform_get_resource(pdev, IORESOURCE_MEM, SMB_BUF_ADDR_RES);
427 if (!res) {
428 dev_err(&pdev->dev, "SMB device failed to get resource\n");
429 return -EINVAL;
430 }
431
432 sdb->buf_rdptr = 0;
433 sdb->buf_hw_base = FIELD_GET(SMB_BUF_ADDR_LO_MSK, res->start);
434 sdb->buf_size = resource_size(res);
435 if (sdb->buf_size == 0)
436 return -EINVAL;
437
438 /*
439 * This is a chunk of memory, use classic mapping with better
440 * performance.
441 */
442 base = devm_memremap(&pdev->dev, sdb->buf_hw_base, sdb->buf_size,
443 MEMREMAP_WB);
444 if (IS_ERR(base))
445 return PTR_ERR(base);
446
447 sdb->buf_base = base;
448
449 return 0;
450}
451
452static void smb_init_hw(struct smb_drv_data *drvdata)
453{
454 smb_disable_hw(drvdata);
455
456 writel(SMB_LB_CFG_LO_DEFAULT, drvdata->base + SMB_LB_CFG_LO_REG);
457 writel(SMB_LB_CFG_HI_DEFAULT, drvdata->base + SMB_LB_CFG_HI_REG);
458 writel(SMB_GLB_CFG_DEFAULT, drvdata->base + SMB_GLB_CFG_REG);
459 writel(SMB_GLB_INT_CFG, drvdata->base + SMB_GLB_INT_REG);
460 writel(SMB_LB_INT_CTRL_CFG, drvdata->base + SMB_LB_INT_CTRL_REG);
461}
462
463static int smb_register_sink(struct platform_device *pdev,
464 struct smb_drv_data *drvdata)
465{
466 struct coresight_platform_data *pdata = NULL;
467 struct coresight_desc desc = { 0 };
468 int ret;
469
470 pdata = coresight_get_platform_data(&pdev->dev);
471 if (IS_ERR(pdata))
472 return PTR_ERR(pdata);
473
474 desc.type = CORESIGHT_DEV_TYPE_SINK;
475 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
476 desc.ops = &cs_ops;
477 desc.pdata = pdata;
478 desc.dev = &pdev->dev;
479 desc.groups = smb_sink_groups;
480 desc.name = coresight_alloc_device_name(&sink_devs, &pdev->dev);
481 if (!desc.name) {
482 dev_err(&pdev->dev, "Failed to alloc coresight device name");
483 return -ENOMEM;
484 }
485 desc.access = CSDEV_ACCESS_IOMEM(drvdata->base);
486
487 drvdata->csdev = coresight_register(&desc);
488 if (IS_ERR(drvdata->csdev))
489 return PTR_ERR(drvdata->csdev);
490
491 drvdata->miscdev.name = desc.name;
492 drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
493 drvdata->miscdev.fops = &smb_fops;
494 ret = misc_register(&drvdata->miscdev);
495 if (ret) {
496 coresight_unregister(drvdata->csdev);
497 dev_err(&pdev->dev, "Failed to register misc, ret=%d\n", ret);
498 }
499
500 return ret;
501}
502
503static void smb_unregister_sink(struct smb_drv_data *drvdata)
504{
505 misc_deregister(&drvdata->miscdev);
506 coresight_unregister(drvdata->csdev);
507}
508
509static int smb_config_inport(struct device *dev, bool enable)
510{
511 u64 func = enable ? 1 : 0;
512 union acpi_object *obj;
513 guid_t guid;
514 u64 rev = 0;
515
516 /*
517 * Using DSM calls to enable/disable ultrasoc hardwares on
518 * tracing path, to prevent ultrasoc packet format being exposed.
519 */
520 if (guid_parse(ULTRASOC_SMB_DSM_UUID, &guid)) {
521 dev_err(dev, "Get GUID failed\n");
522 return -EINVAL;
523 }
524
525 obj = acpi_evaluate_dsm(ACPI_HANDLE(dev), &guid, rev, func, NULL);
526 if (!obj) {
527 dev_err(dev, "ACPI handle failed\n");
528 return -ENODEV;
529 }
530
531 ACPI_FREE(obj);
532
533 return 0;
534}
535
536static int smb_probe(struct platform_device *pdev)
537{
538 struct device *dev = &pdev->dev;
539 struct smb_drv_data *drvdata;
540 int ret;
541
542 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
543 if (!drvdata)
544 return -ENOMEM;
545
546 drvdata->base = devm_platform_ioremap_resource(pdev, SMB_REG_ADDR_RES);
547 if (IS_ERR(drvdata->base)) {
548 dev_err(dev, "Failed to ioremap resource\n");
549 return PTR_ERR(drvdata->base);
550 }
551
552 smb_init_hw(drvdata);
553
554 ret = smb_init_data_buffer(pdev, &drvdata->sdb);
555 if (ret) {
556 dev_err(dev, "Failed to init buffer, ret = %d\n", ret);
557 return ret;
558 }
559
560 ret = smb_config_inport(dev, true);
561 if (ret)
562 return ret;
563
564 smb_reset_buffer(drvdata);
565 platform_set_drvdata(pdev, drvdata);
566 spin_lock_init(&drvdata->spinlock);
567 drvdata->pid = -1;
568
569 ret = smb_register_sink(pdev, drvdata);
570 if (ret) {
571 smb_config_inport(&pdev->dev, false);
572 dev_err(dev, "Failed to register SMB sink\n");
573 return ret;
574 }
575
576 return 0;
577}
578
579static void smb_remove(struct platform_device *pdev)
580{
581 struct smb_drv_data *drvdata = platform_get_drvdata(pdev);
582
583 smb_unregister_sink(drvdata);
584
585 smb_config_inport(&pdev->dev, false);
586}
587
588#ifdef CONFIG_ACPI
589static const struct acpi_device_id ultrasoc_smb_acpi_match[] = {
590 {"HISI03A1", 0, 0, 0},
591 {}
592};
593MODULE_DEVICE_TABLE(acpi, ultrasoc_smb_acpi_match);
594#endif
595
596static struct platform_driver smb_driver = {
597 .driver = {
598 .name = "ultrasoc-smb",
599 .acpi_match_table = ACPI_PTR(ultrasoc_smb_acpi_match),
600 .suppress_bind_attrs = true,
601 },
602 .probe = smb_probe,
603 .remove = smb_remove,
604};
605module_platform_driver(smb_driver);
606
607MODULE_DESCRIPTION("UltraSoc SMB CoreSight driver");
608MODULE_LICENSE("Dual MIT/GPL");
609MODULE_AUTHOR("Jonathan Zhou <jonathan.zhouwen@huawei.com>");
610MODULE_AUTHOR("Qi Liu <liuqi115@huawei.com>");