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->csdev);
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;
255 struct csdev_access *csa = &drvdata->csdev->access;
257 CS_UNLOCK(drvdata->base);
259 ffcr = readl_relaxed(drvdata->base + ETB_FFCR);
260 /* stop formatter when a stop has completed */
261 ffcr |= ETB_FFCR_STOP_FI;
262 writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
263 /* manually generate a flush of the system */
264 ffcr |= ETB_FFCR_FON_MAN;
265 writel_relaxed(ffcr, drvdata->base + ETB_FFCR);
267 if (coresight_timeout(csa, ETB_FFCR, ETB_FFCR_BIT, 0)) {
269 "timeout while waiting for completion of Manual Flush\n");
272 /* disable trace capture */
273 writel_relaxed(0x0, drvdata->base + ETB_CTL_REG);
275 if (coresight_timeout(csa, ETB_FFSR, ETB_FFSR_BIT, 1)) {
277 "timeout while waiting for Formatter to Stop\n");
280 CS_LOCK(drvdata->base);
283 static void etb_dump_hw(struct etb_drvdata *drvdata)
288 u32 read_data, depth;
289 u32 read_ptr, write_ptr;
290 u32 frame_off, frame_endoff;
291 struct device *dev = &drvdata->csdev->dev;
293 CS_UNLOCK(drvdata->base);
295 read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
296 write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
298 frame_off = write_ptr % ETB_FRAME_SIZE_WORDS;
299 frame_endoff = ETB_FRAME_SIZE_WORDS - frame_off;
302 "write_ptr: %lu not aligned to formatter frame size\n",
303 (unsigned long)write_ptr);
304 dev_err(dev, "frameoff: %lu, frame_endoff: %lu\n",
305 (unsigned long)frame_off, (unsigned long)frame_endoff);
306 write_ptr += frame_endoff;
309 if ((readl_relaxed(drvdata->base + ETB_STATUS_REG)
310 & ETB_STATUS_RAM_FULL) == 0) {
311 writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
313 writel_relaxed(write_ptr, drvdata->base + ETB_RAM_READ_POINTER);
317 depth = drvdata->buffer_depth;
318 buf_ptr = drvdata->buf;
319 for (i = 0; i < depth; i++) {
320 read_data = readl_relaxed(drvdata->base +
321 ETB_RAM_READ_DATA_REG);
322 *(u32 *)buf_ptr = read_data;
327 coresight_insert_barrier_packet(drvdata->buf);
330 buf_ptr -= (frame_endoff * 4);
331 for (i = 0; i < frame_endoff; i++) {
339 writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
341 CS_LOCK(drvdata->base);
344 static void etb_disable_hw(struct etb_drvdata *drvdata)
346 __etb_disable_hw(drvdata);
347 etb_dump_hw(drvdata);
348 coresight_disclaim_device(drvdata->csdev);
351 static int etb_disable(struct coresight_device *csdev)
353 struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
356 spin_lock_irqsave(&drvdata->spinlock, flags);
358 if (atomic_dec_return(csdev->refcnt)) {
359 spin_unlock_irqrestore(&drvdata->spinlock, flags);
363 /* Complain if we (somehow) got out of sync */
364 WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
365 etb_disable_hw(drvdata);
366 /* Dissociate from monitored process. */
368 drvdata->mode = CS_MODE_DISABLED;
369 spin_unlock_irqrestore(&drvdata->spinlock, flags);
371 dev_dbg(&csdev->dev, "ETB disabled\n");
375 static void *etb_alloc_buffer(struct coresight_device *csdev,
376 struct perf_event *event, void **pages,
377 int nr_pages, bool overwrite)
380 struct cs_buffers *buf;
382 node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
384 buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
388 buf->pid = task_pid_nr(event->owner);
389 buf->snapshot = overwrite;
390 buf->nr_pages = nr_pages;
391 buf->data_pages = pages;
396 static void etb_free_buffer(void *config)
398 struct cs_buffers *buf = config;
403 static int etb_set_buffer(struct coresight_device *csdev,
404 struct perf_output_handle *handle)
408 struct cs_buffers *buf = etm_perf_sink_config(handle);
413 /* wrap head around to the amount of space we have */
414 head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
416 /* find the page to write to */
417 buf->cur = head / PAGE_SIZE;
419 /* and offset within that page */
420 buf->offset = head % PAGE_SIZE;
422 local_set(&buf->data_size, 0);
427 static unsigned long etb_update_buffer(struct coresight_device *csdev,
428 struct perf_output_handle *handle,
435 u32 read_ptr, write_ptr, capacity;
436 u32 status, read_data;
437 unsigned long offset, to_read = 0, flags;
438 struct cs_buffers *buf = sink_config;
439 struct etb_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
444 capacity = drvdata->buffer_depth * ETB_FRAME_SIZE_WORDS;
446 spin_lock_irqsave(&drvdata->spinlock, flags);
448 /* Don't do anything if another tracer is using this sink */
449 if (atomic_read(csdev->refcnt) != 1)
452 __etb_disable_hw(drvdata);
453 CS_UNLOCK(drvdata->base);
455 /* unit is in words, not bytes */
456 read_ptr = readl_relaxed(drvdata->base + ETB_RAM_READ_POINTER);
457 write_ptr = readl_relaxed(drvdata->base + ETB_RAM_WRITE_POINTER);
460 * Entries should be aligned to the frame size. If they are not
461 * go back to the last alignment point to give decoding tools a
462 * chance to fix things.
464 if (write_ptr % ETB_FRAME_SIZE_WORDS) {
466 "write_ptr: %lu not aligned to formatter frame size\n",
467 (unsigned long)write_ptr);
469 write_ptr &= ~(ETB_FRAME_SIZE_WORDS - 1);
474 * Get a hold of the status register and see if a wrap around
475 * has occurred. If so adjust things accordingly. Otherwise
476 * start at the beginning and go until the write pointer has
479 status = readl_relaxed(drvdata->base + ETB_STATUS_REG);
480 if (status & ETB_STATUS_RAM_FULL) {
483 read_ptr = write_ptr;
485 to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->buffer_depth);
486 to_read *= ETB_FRAME_SIZE_WORDS;
490 * Make sure we don't overwrite data that hasn't been consumed yet.
491 * It is entirely possible that the HW buffer has more data than the
492 * ring buffer can currently handle. If so adjust the start address
493 * to take only the last traces.
495 * In snapshot mode we are looking to get the latest traces only and as
496 * such, we don't care about not overwriting data that hasn't been
497 * processed by user space.
499 if (!buf->snapshot && to_read > handle->size) {
500 u32 mask = ~(ETB_FRAME_SIZE_WORDS - 1);
502 /* The new read pointer must be frame size aligned */
503 to_read = handle->size & mask;
505 * Move the RAM read pointer up, keeping in mind that
506 * everything is in frame size units.
508 read_ptr = (write_ptr + drvdata->buffer_depth) -
509 to_read / ETB_FRAME_SIZE_WORDS;
510 /* Wrap around if need be*/
511 if (read_ptr > (drvdata->buffer_depth - 1))
512 read_ptr -= drvdata->buffer_depth;
513 /* let the decoder know we've skipped ahead */
518 * Don't set the TRUNCATED flag in snapshot mode because 1) the
519 * captured buffer is expected to be truncated and 2) a full buffer
520 * prevents the event from being re-enabled by the perf core,
521 * resulting in stale data being send to user space.
523 if (!buf->snapshot && lost)
524 perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
526 /* finally tell HW where we want to start reading from */
527 writel_relaxed(read_ptr, drvdata->base + ETB_RAM_READ_POINTER);
530 offset = buf->offset;
531 barrier = coresight_barrier_pkt;
533 for (i = 0; i < to_read; i += 4) {
534 buf_ptr = buf->data_pages[cur] + offset;
535 read_data = readl_relaxed(drvdata->base +
536 ETB_RAM_READ_DATA_REG);
537 if (lost && i < CORESIGHT_BARRIER_PKT_SIZE) {
538 read_data = *barrier;
542 *(u32 *)buf_ptr = read_data;
546 if (offset >= PAGE_SIZE) {
549 /* wrap around at the end of the buffer */
550 cur &= buf->nr_pages - 1;
554 /* reset ETB buffer for next run */
555 writel_relaxed(0x0, drvdata->base + ETB_RAM_READ_POINTER);
556 writel_relaxed(0x0, drvdata->base + ETB_RAM_WRITE_POINTER);
559 * In snapshot mode we simply increment the head by the number of byte
560 * that were written. User space will figure out how many bytes to get
561 * from the AUX buffer based on the 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 static struct attribute *coresight_etb_mgmt_attrs[] = {
659 coresight_simple_reg32(rdp, ETB_RAM_DEPTH_REG),
660 coresight_simple_reg32(sts, ETB_STATUS_REG),
661 coresight_simple_reg32(rrp, ETB_RAM_READ_POINTER),
662 coresight_simple_reg32(rwp, ETB_RAM_WRITE_POINTER),
663 coresight_simple_reg32(trg, ETB_TRG),
664 coresight_simple_reg32(ctl, ETB_CTL_REG),
665 coresight_simple_reg32(ffsr, ETB_FFSR),
666 coresight_simple_reg32(ffcr, ETB_FFCR),
670 static ssize_t trigger_cntr_show(struct device *dev,
671 struct device_attribute *attr, char *buf)
673 struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
674 unsigned long val = drvdata->trigger_cntr;
676 return sprintf(buf, "%#lx\n", val);
679 static ssize_t trigger_cntr_store(struct device *dev,
680 struct device_attribute *attr,
681 const char *buf, size_t size)
685 struct etb_drvdata *drvdata = dev_get_drvdata(dev->parent);
687 ret = kstrtoul(buf, 16, &val);
691 drvdata->trigger_cntr = val;
694 static DEVICE_ATTR_RW(trigger_cntr);
696 static struct attribute *coresight_etb_attrs[] = {
697 &dev_attr_trigger_cntr.attr,
701 static const struct attribute_group coresight_etb_group = {
702 .attrs = coresight_etb_attrs,
705 static const struct attribute_group coresight_etb_mgmt_group = {
706 .attrs = coresight_etb_mgmt_attrs,
710 static const struct attribute_group *coresight_etb_groups[] = {
711 &coresight_etb_group,
712 &coresight_etb_mgmt_group,
716 static int etb_probe(struct amba_device *adev, const struct amba_id *id)
720 struct device *dev = &adev->dev;
721 struct coresight_platform_data *pdata = NULL;
722 struct etb_drvdata *drvdata;
723 struct resource *res = &adev->res;
724 struct coresight_desc desc = { 0 };
726 desc.name = coresight_alloc_device_name(&etb_devs, dev);
730 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
734 drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
735 if (!IS_ERR(drvdata->atclk)) {
736 ret = clk_prepare_enable(drvdata->atclk);
740 dev_set_drvdata(dev, drvdata);
742 /* validity for the resource is already checked by the AMBA core */
743 base = devm_ioremap_resource(dev, res);
745 return PTR_ERR(base);
747 drvdata->base = base;
748 desc.access = CSDEV_ACCESS_IOMEM(base);
750 spin_lock_init(&drvdata->spinlock);
752 drvdata->buffer_depth = etb_get_buffer_depth(drvdata);
754 if (drvdata->buffer_depth & 0x80000000)
757 drvdata->buf = devm_kcalloc(dev,
758 drvdata->buffer_depth, 4, GFP_KERNEL);
762 /* This device is not associated with a session */
765 pdata = coresight_get_platform_data(dev);
767 return PTR_ERR(pdata);
768 adev->dev.platform_data = pdata;
770 desc.type = CORESIGHT_DEV_TYPE_SINK;
771 desc.subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
772 desc.ops = &etb_cs_ops;
775 desc.groups = coresight_etb_groups;
776 drvdata->csdev = coresight_register(&desc);
777 if (IS_ERR(drvdata->csdev))
778 return PTR_ERR(drvdata->csdev);
780 drvdata->miscdev.name = desc.name;
781 drvdata->miscdev.minor = MISC_DYNAMIC_MINOR;
782 drvdata->miscdev.fops = &etb_fops;
783 ret = misc_register(&drvdata->miscdev);
785 goto err_misc_register;
787 pm_runtime_put(&adev->dev);
791 coresight_unregister(drvdata->csdev);
795 static void etb_remove(struct amba_device *adev)
797 struct etb_drvdata *drvdata = dev_get_drvdata(&adev->dev);
800 * Since misc_open() holds a refcount on the f_ops, which is
801 * etb fops in this case, device is there until last file
802 * handler to this device is closed.
804 misc_deregister(&drvdata->miscdev);
805 coresight_unregister(drvdata->csdev);
809 static int etb_runtime_suspend(struct device *dev)
811 struct etb_drvdata *drvdata = dev_get_drvdata(dev);
813 if (drvdata && !IS_ERR(drvdata->atclk))
814 clk_disable_unprepare(drvdata->atclk);
819 static int etb_runtime_resume(struct device *dev)
821 struct etb_drvdata *drvdata = dev_get_drvdata(dev);
823 if (drvdata && !IS_ERR(drvdata->atclk))
824 clk_prepare_enable(drvdata->atclk);
830 static const struct dev_pm_ops etb_dev_pm_ops = {
831 SET_RUNTIME_PM_OPS(etb_runtime_suspend, etb_runtime_resume, NULL)
834 static const struct amba_id etb_ids[] = {
842 MODULE_DEVICE_TABLE(amba, etb_ids);
844 static struct amba_driver etb_driver = {
846 .name = "coresight-etb10",
847 .owner = THIS_MODULE,
848 .pm = &etb_dev_pm_ops,
849 .suppress_bind_attrs = true,
853 .remove = etb_remove,
857 module_amba_driver(etb_driver);
859 MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
860 MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
861 MODULE_DESCRIPTION("Arm CoreSight Embedded Trace Buffer driver");
862 MODULE_LICENSE("GPL v2");