1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
5 * Description: CoreSight Embedded Trace Buffer driver
8 #include <linux/atomic.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/types.h>
12 #include <linux/device.h>
14 #include <linux/err.h>
16 #include <linux/miscdevice.h>
17 #include <linux/uaccess.h>
18 #include <linux/slab.h>
19 #include <linux/spinlock.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/seq_file.h>
22 #include <linux/coresight.h>
23 #include <linux/amba/bus.h>
24 #include <linux/clk.h>
25 #include <linux/circ_buf.h>
27 #include <linux/perf_event.h>
30 #include "coresight-priv.h"
31 #include "coresight-etm-perf.h"
33 #define ETB_RAM_DEPTH_REG 0x004
34 #define ETB_STATUS_REG 0x00c
35 #define ETB_RAM_READ_DATA_REG 0x010
36 #define ETB_RAM_READ_POINTER 0x014
37 #define ETB_RAM_WRITE_POINTER 0x018
39 #define ETB_CTL_REG 0x020
40 #define ETB_RWD_REG 0x024
41 #define ETB_FFSR 0x300
42 #define ETB_FFCR 0x304
43 #define ETB_ITMISCOP0 0xee0
44 #define ETB_ITTRFLINACK 0xee4
45 #define ETB_ITTRFLIN 0xee8
46 #define ETB_ITATBDATA0 0xeeC
47 #define ETB_ITATBCTR2 0xef0
48 #define ETB_ITATBCTR1 0xef4
49 #define ETB_ITATBCTR0 0xef8
51 /* register description */
53 #define ETB_STATUS_RAM_FULL BIT(0)
55 #define ETB_CTL_CAPT_EN BIT(0)
57 #define ETB_FFCR_EN_FTC BIT(0)
58 #define ETB_FFCR_FON_MAN BIT(6)
59 #define ETB_FFCR_STOP_FI BIT(12)
60 #define ETB_FFCR_STOP_TRIGGER BIT(13)
62 #define ETB_FFCR_BIT 6
63 #define ETB_FFSR_BIT 1
64 #define ETB_FRAME_SIZE_WORDS 4
66 DEFINE_CORESIGHT_DEVLIST(etb_devs, "etb");
69 * struct etb_drvdata - specifics associated to an ETB component
70 * @base: memory mapped base address for this component.
71 * @atclk: optional clock for the core parts of the ETB.
72 * @csdev: component vitals needed by the framework.
73 * @miscdev: specifics to handle "/dev/xyz.etb" entry.
74 * @spinlock: only one at a time pls.
75 * @reading: synchronise user space access to etb buffer.
76 * @pid: Process ID of the process being monitored by the session
77 * that is using this component.
78 * @buf: area of memory where ETB buffer content gets sent.
79 * @mode: this ETB is being used.
80 * @buffer_depth: size of @buf.
81 * @trigger_cntr: amount of words to store after a trigger.
86 struct coresight_device *csdev;
87 struct miscdevice miscdev;
97 static int etb_set_buffer(struct coresight_device *csdev,
98 struct perf_output_handle *handle);
100 static inline unsigned int etb_get_buffer_depth(struct etb_drvdata *drvdata)
102 return readl_relaxed(drvdata->base + ETB_RAM_DEPTH_REG);
105 static void __etb_enable_hw(struct etb_drvdata *drvdata)
110 CS_UNLOCK(drvdata->base);
112 depth = drvdata->buffer_depth;
113 /* reset write RAM pointer address */
114 writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
115 /* clear entire RAM buffer */
116 for (i = 0; i < depth; i++)
117 writel_relaxed(0x0, drvdata->base + ETB_RWD_REG);
119 /* reset write RAM pointer address */
120 writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
121 /* reset read RAM pointer address */
122 writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
124 writel_relaxed(drvdata->trigger_cntr, drvdata->base + ETB_TRG);
125 writel_relaxed(ETB_FFCR_EN_FTC | ETB_FFCR_STOP_TRIGGER,
126 drvdata->base + ETB_FFCR);
127 /* ETB trace capture enable */
128 writel_relaxed(ETB_CTL_CAPT_EN, drvdata->base + ETB_CTL_REG);
130 CS_LOCK(drvdata->base);
133 static int etb_enable_hw(struct etb_drvdata *drvdata)
135 int rc = coresight_claim_device(drvdata->base);
140 __etb_enable_hw(drvdata);
144 static int etb_enable_sysfs(struct coresight_device *csdev)
148 struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
150 spin_lock_irqsave(&drvdata->spinlock, flags);
152 /* Don't messup with perf sessions. */
153 if (drvdata->mode == CS_MODE_PERF) {
158 if (drvdata->mode == CS_MODE_DISABLED) {
159 ret = etb_enable_hw(drvdata);
163 drvdata->mode = CS_MODE_SYSFS;
166 atomic_inc(csdev->refcnt);
168 spin_unlock_irqrestore(&drvdata->spinlock, flags);
172 static int etb_enable_perf(struct coresight_device *csdev, void *data)
177 struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
178 struct perf_output_handle *handle = data;
179 struct cs_buffers *buf = etm_perf_sink_config(handle);
181 spin_lock_irqsave(&drvdata->spinlock, flags);
183 /* No need to continue if the component is already in used by sysFS. */
184 if (drvdata->mode == CS_MODE_SYSFS) {
189 /* Get a handle on the pid of the process to monitor */
192 if (drvdata->pid != -1 && drvdata->pid != pid) {
198 * No HW configuration is needed if the sink is already in
199 * use for this session.
201 if (drvdata->pid == pid) {
202 atomic_inc(csdev->refcnt);
207 * We don't have an internal state to clean up if we fail to setup
208 * the perf buffer. So we can perform the step before we turn the
209 * ETB on and leave without cleaning up.
211 ret = etb_set_buffer(csdev, handle);
215 ret = etb_enable_hw(drvdata);
217 /* Associate with monitored process. */
219 drvdata->mode = CS_MODE_PERF;
220 atomic_inc(csdev->refcnt);
224 spin_unlock_irqrestore(&drvdata->spinlock, flags);
228 static int etb_enable(struct coresight_device *csdev, u32 mode, void *data)
234 ret = etb_enable_sysfs(csdev);
237 ret = etb_enable_perf(csdev, data);
247 dev_dbg(&csdev->dev, "ETB enabled\n");
251 static void __etb_disable_hw(struct etb_drvdata *drvdata)
254 struct device *dev = &drvdata->csdev->dev;
256 CS_UNLOCK(drvdata->base);
258 ffcr = readl_relaxed(drvdata->base + ETB_FFCR);
259 /* stop formatter when a stop has completed */
260 ffcr |= ETB_FFCR_STOP_FI;
261 writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
262 /* manually generate a flush of the system */
263 ffcr |= ETB_FFCR_FON_MAN;
264 writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
266 if (coresight_timeout(drvdata->base, ETB_FFCR, ETB_FFCR_BIT, 0)) {
268 "timeout while waiting for completion of Manual Flush\n");
271 /* disable trace capture */
272 writel_relaxed(0x0, drvdata->base + ETB_CTL_REG);
274 if (coresight_timeout(drvdata->base, ETB_FFSR, ETB_FFSR_BIT, 1)) {
276 "timeout while waiting for Formatter to Stop\n");
279 CS_LOCK(drvdata->base);
282 static void etb_dump_hw(struct etb_drvdata *drvdata)
287 u32 read_data, depth;
288 u32 read_ptr, write_ptr;
289 u32 frame_off, frame_endoff;
290 struct device *dev = &drvdata->csdev->dev;
292 CS_UNLOCK(drvdata->base);
294 read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
295 write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
297 frame_off = write_ptr % ETB_FRAME_SIZE_WORDS;
298 frame_endoff = ETB_FRAME_SIZE_WORDS - frame_off;
301 "write_ptr: %lu not aligned to formatter frame size\n",
302 (unsigned long)write_ptr);
303 dev_err(dev, "frameoff: %lu, frame_endoff: %lu\n",
304 (unsigned long)frame_off, (unsigned long)frame_endoff);
305 write_ptr += frame_endoff;
308 if ((readl_relaxed(drvdata->base + ETB_STATUS_REG)
309 & ETB_STATUS_RAM_FULL) == 0) {
310 writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
312 writel_relaxed(write_ptr, drvdata->base + ETB_RAM_READ_POINTER);
316 depth = drvdata->buffer_depth;
317 buf_ptr = drvdata->buf;
318 for (i = 0; i < depth; i++) {
319 read_data = readl_relaxed(drvdata->base +
320 ETB_RAM_READ_DATA_REG);
321 *(u32 *)buf_ptr = read_data;
326 coresight_insert_barrier_packet(drvdata->buf);
329 buf_ptr -= (frame_endoff * 4);
330 for (i = 0; i < frame_endoff; i++) {
338 writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
340 CS_LOCK(drvdata->base);
343 static void etb_disable_hw(struct etb_drvdata *drvdata)
345 __etb_disable_hw(drvdata);
346 etb_dump_hw(drvdata);
347 coresight_disclaim_device(drvdata->base);
350 static int etb_disable(struct coresight_device *csdev)
352 struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
355 spin_lock_irqsave(&drvdata->spinlock, flags);
357 if (atomic_dec_return(csdev->refcnt)) {
358 spin_unlock_irqrestore(&drvdata->spinlock, flags);
362 /* Complain if we (somehow) got out of sync */
363 WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
364 etb_disable_hw(drvdata);
365 /* Dissociate from monitored process. */
367 drvdata->mode = CS_MODE_DISABLED;
368 spin_unlock_irqrestore(&drvdata->spinlock, flags);
370 dev_dbg(&csdev->dev, "ETB disabled\n");
374 static void *etb_alloc_buffer(struct coresight_device *csdev,
375 struct perf_event *event, void **pages,
376 int nr_pages, bool overwrite)
379 struct cs_buffers *buf;
381 node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
383 buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
387 buf->pid = task_pid_nr(event->owner);
388 buf->snapshot = overwrite;
389 buf->nr_pages = nr_pages;
390 buf->data_pages = pages;
395 static void etb_free_buffer(void *config)
397 struct cs_buffers *buf = config;
402 static int etb_set_buffer(struct coresight_device *csdev,
403 struct perf_output_handle *handle)
407 struct cs_buffers *buf = etm_perf_sink_config(handle);
412 /* wrap head around to the amount of space we have */
413 head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
415 /* find the page to write to */
416 buf->cur = head / PAGE_SIZE;
418 /* and offset within that page */
419 buf->offset = head % PAGE_SIZE;
421 local_set(&buf->data_size, 0);
426 static unsigned long etb_update_buffer(struct coresight_device *csdev,
427 struct perf_output_handle *handle,
434 u32 read_ptr, write_ptr, capacity;
435 u32 status, read_data;
436 unsigned long offset, to_read = 0, flags;
437 struct cs_buffers *buf = sink_config;
438 struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
443 capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;
445 spin_lock_irqsave(&drvdata->spinlock, flags);
447 /* Don't do anything if another tracer is using this sink */
448 if (atomic_read(csdev->refcnt) != 1)
451 __etb_disable_hw(drvdata);
452 CS_UNLOCK(drvdata->base);
454 /* unit is in words, not bytes */
455 read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
456 write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
459 * Entries should be aligned to the frame size. If they are not
460 * go back to the last alignment point to give decoding tools a
461 * chance to fix things.
463 if (write_ptr % ETB_FRAME_SIZE_WORDS) {
465 "write_ptr: %lu not aligned to formatter frame size\n",
466 (unsigned long)write_ptr);
468 write_ptr &= ~(ETB_FRAME_SIZE_WORDS - 1);
473 * Get a hold of the status register and see if a wrap around
474 * has occurred. If so adjust things accordingly. Otherwise
475 * start at the beginning and go until the write pointer has
478 status = readl_relaxed(drvdata->base + ETB_STATUS_REG);
479 if (status & ETB_STATUS_RAM_FULL) {
482 read_ptr = write_ptr;
484 to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->buffer_depth);
485 to_read *= ETB_FRAME_SIZE_WORDS;
489 * Make sure we don't overwrite data that hasn't been consumed yet.
490 * It is entirely possible that the HW buffer has more data than the
491 * ring buffer can currently handle. If so adjust the start address
492 * to take only the last traces.
494 * In snapshot mode we are looking to get the latest traces only and as
495 * such, we don't care about not overwriting data that hasn't been
496 * processed by user space.
498 if (!buf->snapshot && to_read > handle->size) {
499 u32 mask = ~(ETB_FRAME_SIZE_WORDS - 1);
501 /* The new read pointer must be frame size aligned */
502 to_read = handle->size & mask;
504 * Move the RAM read pointer up, keeping in mind that
505 * everything is in frame size units.
507 read_ptr = (write_ptr + drvdata->buffer_depth) -
508 to_read / ETB_FRAME_SIZE_WORDS;
509 /* Wrap around if need be*/
510 if (read_ptr > (drvdata->buffer_depth - 1))
511 read_ptr -= drvdata->buffer_depth;
512 /* let the decoder know we've skipped ahead */
517 * Don't set the TRUNCATED flag in snapshot mode because 1) the
518 * captured buffer is expected to be truncated and 2) a full buffer
519 * prevents the event from being re-enabled by the perf core,
520 * resulting in stale data being send to user space.
522 if (!buf->snapshot && lost)
523 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
525 /* finally tell HW where we want to start reading from */
526 writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
529 offset = buf->offset;
530 barrier = coresight_barrier_pkt;
532 for (i = 0; i < to_read; i += 4) {
533 buf_ptr = buf->data_pages[cur] + offset;
534 read_data = readl_relaxed(drvdata->base +
535 ETB_RAM_READ_DATA_REG);
536 if (lost && i < CORESIGHT_BARRIER_PKT_SIZE) {
537 read_data = *barrier;
541 *(u32 *)buf_ptr = read_data;
545 if (offset >= PAGE_SIZE) {
548 /* wrap around at the end of the buffer */
549 cur &= buf->nr_pages - 1;
553 /* reset ETB buffer for next run */
554 writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
555 writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
558 * In snapshot mode we simply increment the head by the number of byte
559 * that were written. User space function cs_etm_find_snapshot() will
560 * figure out how many bytes to get from the AUX buffer based on the
561 * position of the head.
564 handle->head += to_read;
566 __etb_enable_hw(drvdata);
567 CS_LOCK(drvdata->base);
569 spin_unlock_irqrestore(&drvdata->spinlock, flags);
574 static const struct coresight_ops_sink etb_sink_ops = {
575 .enable = etb_enable,
576 .disable = etb_disable,
577 .alloc_buffer = etb_alloc_buffer,
578 .free_buffer = etb_free_buffer,
579 .update_buffer = etb_update_buffer,
582 static const struct coresight_ops etb_cs_ops = {
583 .sink_ops = &etb_sink_ops,
586 static void etb_dump(struct etb_drvdata *drvdata)
590 spin_lock_irqsave(&drvdata->spinlock, flags);
591 if (drvdata->mode == CS_MODE_SYSFS) {
592 __etb_disable_hw(drvdata);
593 etb_dump_hw(drvdata);
594 __etb_enable_hw(drvdata);
596 spin_unlock_irqrestore(&drvdata->spinlock, flags);
598 dev_dbg(&drvdata->csdev->dev, "ETB dumped\n");
601 static int etb_open(struct inode *inode, struct file *file)
603 struct etb_drvdata *drvdata = container_of(file->private_data,
604 struct etb_drvdata, miscdev);
606 if (local_cmpxchg(&drvdata->reading, 0, 1))
609 dev_dbg(&drvdata->csdev->dev, "%s: successfully opened\n", __func__);
613 static ssize_t etb_read(struct file *file, char __user *data,
614 size_t len, loff_t *ppos)
617 struct etb_drvdata *drvdata = container_of(file->private_data,
618 struct etb_drvdata, miscdev);
619 struct device *dev = &drvdata->csdev->dev;
623 depth = drvdata->buffer_depth;
624 if (*ppos + len > depth * 4)
625 len = depth * 4 - *ppos;
627 if (copy_to_user(data, drvdata->buf + *ppos, len)) {
629 "%s: copy_to_user failed\n", __func__);
635 dev_dbg(dev, "%s: %zu bytes copied, %d bytes left\n",
636 __func__, len, (int)(depth * 4 - *ppos));
640 static int etb_release(struct inode *inode, struct file *file)
642 struct etb_drvdata *drvdata = container_of(file->private_data,
643 struct etb_drvdata, miscdev);
644 local_set(&drvdata->reading, 0);
646 dev_dbg(&drvdata->csdev->dev, "%s: released\n", __func__);
650 static const struct file_operations etb_fops = {
651 .owner = THIS_MODULE,
654 .release = etb_release,
658 #define coresight_etb10_reg(name, offset) \
659 coresight_simple_reg32(struct etb_drvdata, name, offset)
661 coresight_etb10_reg(rdp, ETB_RAM_DEPTH_REG);
662 coresight_etb10_reg(sts, ETB_STATUS_REG);
663 coresight_etb10_reg(rrp, ETB_RAM_READ_POINTER);
664 coresight_etb10_reg(rwp, ETB_RAM_WRITE_POINTER);
665 coresight_etb10_reg(trg, ETB_TRG);
666 coresight_etb10_reg(ctl, ETB_CTL_REG);
667 coresight_etb10_reg(ffsr, ETB_FFSR);
668 coresight_etb10_reg(ffcr, ETB_FFCR);
670 static struct attribute *coresight_etb_mgmt_attrs[] = {
682 static ssize_t trigger_cntr_show(struct device *dev,
683 struct device_attribute *attr, char *buf)
685 struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
686 unsigned long val = drvdata->trigger_cntr;
688 return sprintf(buf, "%#lx\n", val);
691 static ssize_t trigger_cntr_store(struct device *dev,
692 struct device_attribute *attr,
693 const char *buf, size_t size)
697 struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
699 ret = kstrtoul(buf, 16, &val);
703 drvdata->trigger_cntr = val;
706 static DEVICE_ATTR_RW(trigger_cntr);
708 static struct attribute *coresight_etb_attrs[] = {
709 &dev_attr_trigger_cntr.attr,
713 static const struct attribute_group coresight_etb_group = {
714 .attrs = coresight_etb_attrs,
717 static const struct attribute_group coresight_etb_mgmt_group = {
718 .attrs = coresight_etb_mgmt_attrs,
722 static const struct attribute_group *coresight_etb_groups[] = {
723 &coresight_etb_group,
724 &coresight_etb_mgmt_group,
728 static int etb_probe(struct amba_device *adev, const struct amba_id *id)
732 struct device *dev = &adev->dev;
733 struct coresight_platform_data *pdata = NULL;
734 struct etb_drvdata *drvdata;
735 struct resource *res = &adev->res;
736 struct coresight_desc desc = { 0 };
738 desc.name = coresight_alloc_device_name(&etb_devs, dev);
742 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
746 drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
747 if (!IS_ERR(drvdata->atclk)) {
748 ret = clk_prepare_enable(drvdata->atclk);
752 dev_set_drvdata(dev, drvdata);
754 /* validity for the resource is already checked by the AMBA core */
755 base = devm_ioremap_resource(dev, res);
757 return PTR_ERR(base);
759 drvdata->base = base;
761 spin_lock_init(&drvdata->spinlock);
763 drvdata->buffer_depth = etb_get_buffer_depth(drvdata);
765 if (drvdata->buffer_depth & 0x80000000)
768 drvdata->buf = devm_kcalloc(dev,
769 drvdata->buffer_depth, 4, GFP_KERNEL);
773 /* This device is not associated with a session */
776 pdata = coresight_get_platform_data(dev);
778 return PTR_ERR(pdata);
779 adev->dev.platform_data = pdata;
781 desc.type = CORESIGHT_DEV_TYPE_SINK;
782 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
783 desc.ops = &etb_cs_ops;
786 desc.groups = coresight_etb_groups;
787 drvdata->csdev = coresight_register(&desc);
788 if (IS_ERR(drvdata->csdev))
789 return PTR_ERR(drvdata->csdev);
791 drvdata->miscdev.name = desc.name;
792 drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
793 drvdata->miscdev.fops = &etb_fops;
794 ret = misc_register(&drvdata->miscdev);
796 goto err_misc_register;
798 pm_runtime_put(&adev->dev);
802 coresight_unregister(drvdata->csdev);
806 static void etb_remove(struct amba_device *adev)
808 struct etb_drvdata *drvdata = dev_get_drvdata(&adev->dev);
811 * Since misc_open() holds a refcount on the f_ops, which is
812 * etb fops in this case, device is there until last file
813 * handler to this device is closed.
815 misc_deregister(&drvdata->miscdev);
816 coresight_unregister(drvdata->csdev);
820 static int etb_runtime_suspend(struct device *dev)
822 struct etb_drvdata *drvdata = dev_get_drvdata(dev);
824 if (drvdata && !IS_ERR(drvdata->atclk))
825 clk_disable_unprepare(drvdata->atclk);
830 static int etb_runtime_resume(struct device *dev)
832 struct etb_drvdata *drvdata = dev_get_drvdata(dev);
834 if (drvdata && !IS_ERR(drvdata->atclk))
835 clk_prepare_enable(drvdata->atclk);
841 static const struct dev_pm_ops etb_dev_pm_ops = {
842 SET_RUNTIME_PM_OPS(etb_runtime_suspend, etb_runtime_resume, NULL)
845 static const struct amba_id etb_ids[] = {
853 MODULE_DEVICE_TABLE(amba, etb_ids);
855 static struct amba_driver etb_driver = {
857 .name = "coresight-etb10",
858 .owner = THIS_MODULE,
859 .pm = &etb_dev_pm_ops,
860 .suppress_bind_attrs = true,
864 .remove = etb_remove,
868 module_amba_driver(etb_driver);
870 MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
871 MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
872 MODULE_DESCRIPTION("Arm CoreSight Embedded Trace Buffer driver");
873 MODULE_LICENSE("GPL v2");