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(addr: 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(addr: 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(val: sdb->buf_hw_base + sdb->buf_rdptr,
62 addr: 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, addr: drvdata->base + SMB_LB_PURGE_REG);
78
79 /* Reset SMB logical buffer status flags */
80 writel(SMB_LB_INT_STS_RESET, addr: drvdata->base + SMB_LB_INT_STS_REG);
81
82 write_ptr = readl(addr: 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(val: write_ptr, addr: 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(raw_spinlock)(l: &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(to: data, from: sdb->buf_base + sdb->buf_rdptr, n: 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, nbytes: 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(raw_spinlock)(l: &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: dev->parent);
172
173 return sysfs_emit(buf, fmt: "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, addr: drvdata->base + SMB_GLB_EN_REG);
198}
199
200static void smb_disable_hw(struct smb_drv_data *drvdata)
201{
202 writel(val: 0x0, addr: 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(dev: 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, new_mode: CS_MODE_SYSFS);
214}
215
216static int smb_enable_perf(struct coresight_device *csdev,
217 struct coresight_path *path)
218{
219 struct smb_drv_data *drvdata = dev_get_drvdata(dev: csdev->dev.parent);
220 struct perf_output_handle *handle = path->handle;
221 struct cs_buffers *buf = etm_perf_sink_config(handle);
222 pid_t pid;
223
224 if (!buf)
225 return -EINVAL;
226
227 /* Get a handle on the pid of the target process */
228 pid = buf->pid;
229
230 /* Device is already in used by other session */
231 if (drvdata->pid != -1 && drvdata->pid != pid)
232 return -EBUSY;
233
234 if (drvdata->pid == -1) {
235 smb_enable_hw(drvdata);
236 drvdata->pid = pid;
237 coresight_set_mode(csdev, new_mode: CS_MODE_PERF);
238 }
239
240 return 0;
241}
242
243static int smb_enable(struct coresight_device *csdev, enum cs_mode mode,
244 struct coresight_path *path)
245{
246 struct smb_drv_data *drvdata = dev_get_drvdata(dev: csdev->dev.parent);
247 int ret = 0;
248
249 guard(raw_spinlock)(l: &drvdata->spinlock);
250
251 /* Do nothing, the trace data is reading by other interface now */
252 if (drvdata->reading)
253 return -EBUSY;
254
255 /* Do nothing, the SMB is already enabled as other mode */
256 if (coresight_get_mode(csdev) != CS_MODE_DISABLED &&
257 coresight_get_mode(csdev) != mode)
258 return -EBUSY;
259
260 switch (mode) {
261 case CS_MODE_SYSFS:
262 smb_enable_sysfs(csdev);
263 break;
264 case CS_MODE_PERF:
265 ret = smb_enable_perf(csdev, path);
266 break;
267 default:
268 ret = -EINVAL;
269 }
270
271 if (ret)
272 return ret;
273
274 csdev->refcnt++;
275 dev_dbg(&csdev->dev, "Ultrasoc SMB enabled\n");
276
277 return ret;
278}
279
280static int smb_disable(struct coresight_device *csdev)
281{
282 struct smb_drv_data *drvdata = dev_get_drvdata(dev: csdev->dev.parent);
283
284 guard(raw_spinlock)(l: &drvdata->spinlock);
285
286 if (drvdata->reading)
287 return -EBUSY;
288
289 csdev->refcnt--;
290 if (csdev->refcnt)
291 return -EBUSY;
292
293 /* Complain if we (somehow) got out of sync */
294 WARN_ON_ONCE(coresight_get_mode(csdev) == CS_MODE_DISABLED);
295
296 smb_disable_hw(drvdata);
297
298 /* Dissociate from the target process. */
299 drvdata->pid = -1;
300 coresight_set_mode(csdev, new_mode: CS_MODE_DISABLED);
301 dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n");
302
303 return 0;
304}
305
306static void *smb_alloc_buffer(struct coresight_device *csdev,
307 struct perf_event *event, void **pages,
308 int nr_pages, bool overwrite)
309{
310 struct cs_buffers *buf;
311 int node;
312
313 node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(cpu: event->cpu);
314 buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
315 if (!buf)
316 return NULL;
317
318 buf->snapshot = overwrite;
319 buf->nr_pages = nr_pages;
320 buf->data_pages = pages;
321 buf->pid = task_pid_nr(tsk: event->owner);
322
323 return buf;
324}
325
326static void smb_free_buffer(void *config)
327{
328 struct cs_buffers *buf = config;
329
330 kfree(objp: buf);
331}
332
333static void smb_sync_perf_buffer(struct smb_drv_data *drvdata,
334 struct cs_buffers *buf,
335 unsigned long head)
336{
337 struct smb_data_buffer *sdb = &drvdata->sdb;
338 char **dst_pages = (char **)buf->data_pages;
339 unsigned long to_copy;
340 long pg_idx, pg_offset;
341
342 pg_idx = head >> PAGE_SHIFT;
343 pg_offset = head & (PAGE_SIZE - 1);
344
345 while (sdb->data_size) {
346 unsigned long pg_space = PAGE_SIZE - pg_offset;
347
348 to_copy = min(sdb->data_size, pg_space);
349
350 /* Copy parts of trace data when read pointer wrap around */
351 if (sdb->buf_rdptr + to_copy > sdb->buf_size)
352 to_copy = sdb->buf_size - sdb->buf_rdptr;
353
354 memcpy(dst_pages[pg_idx] + pg_offset,
355 sdb->buf_base + sdb->buf_rdptr, to_copy);
356
357 pg_offset += to_copy;
358 if (pg_offset >= PAGE_SIZE) {
359 pg_offset = 0;
360 pg_idx++;
361 pg_idx %= buf->nr_pages;
362 }
363 smb_update_read_ptr(drvdata, nbytes: to_copy);
364 }
365
366 smb_reset_buffer(drvdata);
367}
368
369static unsigned long smb_update_buffer(struct coresight_device *csdev,
370 struct perf_output_handle *handle,
371 void *sink_config)
372{
373 struct smb_drv_data *drvdata = dev_get_drvdata(dev: csdev->dev.parent);
374 struct smb_data_buffer *sdb = &drvdata->sdb;
375 struct cs_buffers *buf = sink_config;
376 unsigned long data_size;
377 bool lost = false;
378
379 if (!buf)
380 return 0;
381
382 guard(raw_spinlock)(l: &drvdata->spinlock);
383
384 /* Don't do anything if another tracer is using this sink. */
385 if (csdev->refcnt != 1)
386 return 0;
387
388 smb_disable_hw(drvdata);
389 smb_update_data_size(drvdata);
390
391 /*
392 * The SMB buffer may be bigger than the space available in the
393 * perf ring buffer (handle->size). If so advance the offset so
394 * that we get the latest trace data.
395 */
396 if (sdb->data_size > handle->size) {
397 smb_update_read_ptr(drvdata, nbytes: sdb->data_size - handle->size);
398 lost = true;
399 }
400
401 data_size = sdb->data_size;
402 smb_sync_perf_buffer(drvdata, buf, head: handle->head);
403 if (!buf->snapshot && lost)
404 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
405
406 return data_size;
407}
408
409static const struct coresight_ops_sink smb_cs_ops = {
410 .enable = smb_enable,
411 .disable = smb_disable,
412 .alloc_buffer = smb_alloc_buffer,
413 .free_buffer = smb_free_buffer,
414 .update_buffer = smb_update_buffer,
415};
416
417static const struct coresight_ops cs_ops = {
418 .sink_ops = &smb_cs_ops,
419};
420
421static int smb_init_data_buffer(struct platform_device *pdev,
422 struct smb_data_buffer *sdb)
423{
424 struct resource *res;
425 void *base;
426
427 res = platform_get_resource(pdev, IORESOURCE_MEM, SMB_BUF_ADDR_RES);
428 if (!res) {
429 dev_err(&pdev->dev, "SMB device failed to get resource\n");
430 return -EINVAL;
431 }
432
433 sdb->buf_rdptr = 0;
434 sdb->buf_hw_base = FIELD_GET(SMB_BUF_ADDR_LO_MSK, res->start);
435 sdb->buf_size = resource_size(res);
436 if (sdb->buf_size == 0)
437 return -EINVAL;
438
439 /*
440 * This is a chunk of memory, use classic mapping with better
441 * performance.
442 */
443 base = devm_memremap(dev: &pdev->dev, offset: sdb->buf_hw_base, size: sdb->buf_size,
444 flags: MEMREMAP_WB);
445 if (IS_ERR(ptr: base))
446 return PTR_ERR(ptr: base);
447
448 sdb->buf_base = base;
449
450 return 0;
451}
452
453static void smb_init_hw(struct smb_drv_data *drvdata)
454{
455 smb_disable_hw(drvdata);
456
457 writel(SMB_LB_CFG_LO_DEFAULT, addr: drvdata->base + SMB_LB_CFG_LO_REG);
458 writel(SMB_LB_CFG_HI_DEFAULT, addr: drvdata->base + SMB_LB_CFG_HI_REG);
459 writel(SMB_GLB_CFG_DEFAULT, addr: drvdata->base + SMB_GLB_CFG_REG);
460 writel(SMB_GLB_INT_CFG, addr: drvdata->base + SMB_GLB_INT_REG);
461 writel(SMB_LB_INT_CTRL_CFG, addr: drvdata->base + SMB_LB_INT_CTRL_REG);
462}
463
464static int smb_register_sink(struct platform_device *pdev,
465 struct smb_drv_data *drvdata)
466{
467 struct coresight_platform_data *pdata = NULL;
468 struct coresight_desc desc = { 0 };
469 int ret;
470
471 pdata = coresight_get_platform_data(dev: &pdev->dev);
472 if (IS_ERR(ptr: pdata))
473 return PTR_ERR(ptr: pdata);
474
475 desc.type = CORESIGHT_DEV_TYPE_SINK;
476 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
477 desc.ops = &cs_ops;
478 desc.pdata = pdata;
479 desc.dev = &pdev->dev;
480 desc.groups = smb_sink_groups;
481 desc.name = coresight_alloc_device_name(devs: &sink_devs, dev: &pdev->dev);
482 if (!desc.name) {
483 dev_err(&pdev->dev, "Failed to alloc coresight device name");
484 return -ENOMEM;
485 }
486 desc.access = CSDEV_ACCESS_IOMEM(drvdata->base);
487
488 drvdata->csdev = coresight_register(desc: &desc);
489 if (IS_ERR(ptr: drvdata->csdev))
490 return PTR_ERR(ptr: drvdata->csdev);
491
492 drvdata->miscdev.name = desc.name;
493 drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
494 drvdata->miscdev.fops = &smb_fops;
495 ret = misc_register(misc: &drvdata->miscdev);
496 if (ret) {
497 coresight_unregister(csdev: drvdata->csdev);
498 dev_err(&pdev->dev, "Failed to register misc, ret=%d\n", ret);
499 }
500
501 return ret;
502}
503
504static void smb_unregister_sink(struct smb_drv_data *drvdata)
505{
506 misc_deregister(misc: &drvdata->miscdev);
507 coresight_unregister(csdev: drvdata->csdev);
508}
509
510static int smb_config_inport(struct device *dev, bool enable)
511{
512 u64 func = enable ? 1 : 0;
513 union acpi_object *obj;
514 guid_t guid;
515 u64 rev = 0;
516
517 /*
518 * Using DSM calls to enable/disable ultrasoc hardwares on
519 * tracing path, to prevent ultrasoc packet format being exposed.
520 */
521 if (guid_parse(ULTRASOC_SMB_DSM_UUID, u: &guid)) {
522 dev_err(dev, "Get GUID failed\n");
523 return -EINVAL;
524 }
525
526 obj = acpi_evaluate_dsm(ACPI_HANDLE(dev), guid: &guid, rev, func, NULL);
527 if (!obj) {
528 dev_err(dev, "ACPI handle failed\n");
529 return -ENODEV;
530 }
531
532 ACPI_FREE(obj);
533
534 return 0;
535}
536
537static int smb_probe(struct platform_device *pdev)
538{
539 struct device *dev = &pdev->dev;
540 struct smb_drv_data *drvdata;
541 int ret;
542
543 drvdata = devm_kzalloc(dev, size: sizeof(*drvdata), GFP_KERNEL);
544 if (!drvdata)
545 return -ENOMEM;
546
547 drvdata->base = devm_platform_ioremap_resource(pdev, SMB_REG_ADDR_RES);
548 if (IS_ERR(ptr: drvdata->base)) {
549 dev_err(dev, "Failed to ioremap resource\n");
550 return PTR_ERR(ptr: drvdata->base);
551 }
552
553 smb_init_hw(drvdata);
554
555 ret = smb_init_data_buffer(pdev, sdb: &drvdata->sdb);
556 if (ret) {
557 dev_err(dev, "Failed to init buffer, ret = %d\n", ret);
558 return ret;
559 }
560
561 ret = smb_config_inport(dev, enable: true);
562 if (ret)
563 return ret;
564
565 smb_reset_buffer(drvdata);
566 platform_set_drvdata(pdev, data: drvdata);
567 raw_spin_lock_init(&drvdata->spinlock);
568 drvdata->pid = -1;
569
570 ret = smb_register_sink(pdev, drvdata);
571 if (ret) {
572 smb_config_inport(dev: &pdev->dev, enable: false);
573 dev_err(dev, "Failed to register SMB sink\n");
574 return ret;
575 }
576
577 return 0;
578}
579
580static void smb_remove(struct platform_device *pdev)
581{
582 struct smb_drv_data *drvdata = platform_get_drvdata(pdev);
583
584 smb_unregister_sink(drvdata);
585
586 smb_config_inport(dev: &pdev->dev, enable: false);
587}
588
589#ifdef CONFIG_ACPI
590static const struct acpi_device_id ultrasoc_smb_acpi_match[] = {
591 {"HISI03A1", 0, 0, 0},
592 {}
593};
594MODULE_DEVICE_TABLE(acpi, ultrasoc_smb_acpi_match);
595#endif
596
597static struct platform_driver smb_driver = {
598 .driver = {
599 .name = "ultrasoc-smb",
600 .acpi_match_table = ACPI_PTR(ultrasoc_smb_acpi_match),
601 .suppress_bind_attrs = true,
602 },
603 .probe = smb_probe,
604 .remove = smb_remove,
605};
606module_platform_driver(smb_driver);
607
608MODULE_DESCRIPTION("UltraSoc SMB CoreSight driver");
609MODULE_LICENSE("Dual MIT/GPL");
610MODULE_AUTHOR("Jonathan Zhou <jonathan.zhouwen@huawei.com>");
611MODULE_AUTHOR("Qi Liu <liuqi115@huawei.com>");
612

source code of linux/drivers/hwtracing/coresight/ultrasoc-smb.c