1 files changed, 681 insertions, 0 deletions

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
new file mode 100644
index 000000000..eee069e95
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -0,0 +1,681 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright(C) 2016 Linaro Limited. All rights reserved.
+ * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
+ */
+
+#include <linux/atomic.h>
+#include <linux/circ_buf.h>
+#include <linux/coresight.h>
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+#include "coresight-priv.h"
+#include "coresight-tmc.h"
+#include "coresight-etm-perf.h"
+
+static int tmc_set_etf_buffer(struct coresight_device *csdev,
+			      struct perf_output_handle *handle);
+
+static void __tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
+{
+	CS_UNLOCK(drvdata->base);
+
+	/* Wait for TMCSReady bit to be set */
+	tmc_wait_for_tmcready(drvdata);
+
+	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
+	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
+		       TMC_FFCR_FON_FLIN | TMC_FFCR_FON_TRIG_EVT |
+		       TMC_FFCR_TRIGON_TRIGIN,
+		       drvdata->base + TMC_FFCR);
+
+	writel_relaxed(drvdata->trigger_cntr, drvdata->base + TMC_TRG);
+	tmc_enable_hw(drvdata);
+
+	CS_LOCK(drvdata->base);
+}
+
+static int tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
+{
+	int rc = coresight_claim_device(drvdata->base);
+
+	if (rc)
+		return rc;
+
+	__tmc_etb_enable_hw(drvdata);
+	return 0;
+}
+
+static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
+{
+	char *bufp;
+	u32 read_data, lost;
+
+	/* Check if the buffer wrapped around. */
+	lost = readl_relaxed(drvdata->base + TMC_STS) & TMC_STS_FULL;
+	bufp = drvdata->buf;
+	drvdata->len = 0;
+	while (1) {
+		read_data = readl_relaxed(drvdata->base + TMC_RRD);
+		if (read_data == 0xFFFFFFFF)
+			break;
+		memcpy(bufp, &read_data, 4);
+		bufp += 4;
+		drvdata->len += 4;
+	}
+
+	if (lost)
+		coresight_insert_barrier_packet(drvdata->buf);
+	return;
+}
+
+static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
+{
+	CS_UNLOCK(drvdata->base);
+
+	tmc_flush_and_stop(drvdata);
+	/*
+	 * When operating in sysFS mode the content of the buffer needs to be
+	 * read before the TMC is disabled.
+	 */
+	if (drvdata->mode == CS_MODE_SYSFS)
+		tmc_etb_dump_hw(drvdata);
+	tmc_disable_hw(drvdata);
+
+	CS_LOCK(drvdata->base);
+}
+
+static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
+{
+	__tmc_etb_disable_hw(drvdata);
+	coresight_disclaim_device(drvdata->base);
+}
+
+static void __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
+{
+	CS_UNLOCK(drvdata->base);
+
+	/* Wait for TMCSReady bit to be set */
+	tmc_wait_for_tmcready(drvdata);
+
+	writel_relaxed(TMC_MODE_HARDWARE_FIFO, drvdata->base + TMC_MODE);
+	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI,
+		       drvdata->base + TMC_FFCR);
+	writel_relaxed(0x0, drvdata->base + TMC_BUFWM);
+	tmc_enable_hw(drvdata);
+
+	CS_LOCK(drvdata->base);
+}
+
+static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
+{
+	int rc = coresight_claim_device(drvdata->base);
+
+	if (rc)
+		return rc;
+
+	__tmc_etf_enable_hw(drvdata);
+	return 0;
+}
+
+static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
+{
+	CS_UNLOCK(drvdata->base);
+
+	tmc_flush_and_stop(drvdata);
+	tmc_disable_hw(drvdata);
+	coresight_disclaim_device_unlocked(drvdata->base);
+	CS_LOCK(drvdata->base);
+}
+
+/*
+ * Return the available trace data in the buffer from @pos, with
+ * a maximum limit of @len, updating the @bufpp on where to
+ * find it.
+ */
+ssize_t tmc_etb_get_sysfs_trace(struct tmc_drvdata *drvdata,
+				loff_t pos, size_t len, char **bufpp)
+{
+	ssize_t actual = len;
+
+	/* Adjust the len to available size @pos */
+	if (pos + actual > drvdata->len)
+		actual = drvdata->len - pos;
+	if (actual > 0)
+		*bufpp = drvdata->buf + pos;
+	return actual;
+}
+
+static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
+{
+	int ret = 0;
+	bool used = false;
+	char *buf = NULL;
+	unsigned long flags;
+	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	/*
+	 * If we don't have a buffer release the lock and allocate memory.
+	 * Otherwise keep the lock and move along.
+	 */
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+	if (!drvdata->buf) {
+		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+		/* Allocating the memory here while outside of the spinlock */
+		buf = kzalloc(drvdata->size, GFP_KERNEL);
+		if (!buf)
+			return -ENOMEM;
+
+		/* Let's try again */
+		spin_lock_irqsave(&drvdata->spinlock, flags);
+	}
+
+	if (drvdata->reading) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/*
+	 * In sysFS mode we can have multiple writers per sink.  Since this
+	 * sink is already enabled no memory is needed and the HW need not be
+	 * touched.
+	 */
+	if (drvdata->mode == CS_MODE_SYSFS) {
+		atomic_inc(csdev->refcnt);
+		goto out;
+	}
+
+	/*
+	 * If drvdata::buf isn't NULL, memory was allocated for a previous
+	 * trace run but wasn't read.  If so simply zero-out the memory.
+	 * Otherwise use the memory allocated above.
+	 *
+	 * The memory is freed when users read the buffer using the
+	 * /dev/xyz.{etf|etb} interface.  See tmc_read_unprepare_etf() for
+	 * details.
+	 */
+	if (drvdata->buf) {
+		memset(drvdata->buf, 0, drvdata->size);
+	} else {
+		used = true;
+		drvdata->buf = buf;
+	}
+
+	ret = tmc_etb_enable_hw(drvdata);
+	if (!ret) {
+		drvdata->mode = CS_MODE_SYSFS;
+		atomic_inc(csdev->refcnt);
+	} else {
+		/* Free up the buffer if we failed to enable */
+		used = false;
+	}
+out:
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	/* Free memory outside the spinlock if need be */
+	if (!used)
+		kfree(buf);
+
+	return ret;
+}
+
+static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
+{
+	int ret = 0;
+	pid_t pid;
+	unsigned long flags;
+	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	struct perf_output_handle *handle = data;
+	struct cs_buffers *buf = etm_perf_sink_config(handle);
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+	do {
+		ret = -EINVAL;
+		if (drvdata->reading)
+			break;
+		/*
+		 * No need to continue if the ETB/ETF is already operated
+		 * from sysFS.
+		 */
+		if (drvdata->mode == CS_MODE_SYSFS) {
+			ret = -EBUSY;
+			break;
+		}
+
+		/* Get a handle on the pid of the process to monitor */
+		pid = buf->pid;
+
+		if (drvdata->pid != -1 && drvdata->pid != pid) {
+			ret = -EBUSY;
+			break;
+		}
+
+		ret = tmc_set_etf_buffer(csdev, handle);
+		if (ret)
+			break;
+
+		/*
+		 * No HW configuration is needed if the sink is already in
+		 * use for this session.
+		 */
+		if (drvdata->pid == pid) {
+			atomic_inc(csdev->refcnt);
+			break;
+		}
+
+		ret  = tmc_etb_enable_hw(drvdata);
+		if (!ret) {
+			/* Associate with monitored process. */
+			drvdata->pid = pid;
+			drvdata->mode = CS_MODE_PERF;
+			atomic_inc(csdev->refcnt);
+		}
+	} while (0);
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	return ret;
+}
+
+static int tmc_enable_etf_sink(struct coresight_device *csdev,
+			       u32 mode, void *data)
+{
+	int ret;
+
+	switch (mode) {
+	case CS_MODE_SYSFS:
+		ret = tmc_enable_etf_sink_sysfs(csdev);
+		break;
+	case CS_MODE_PERF:
+		ret = tmc_enable_etf_sink_perf(csdev, data);
+		break;
+	/* We shouldn't be here */
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	if (ret)
+		return ret;
+
+	dev_dbg(&csdev->dev, "TMC-ETB/ETF enabled\n");
+	return 0;
+}
+
+static int tmc_disable_etf_sink(struct coresight_device *csdev)
+{
+	unsigned long flags;
+	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+
+	if (drvdata->reading) {
+		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		return -EBUSY;
+	}
+
+	if (atomic_dec_return(csdev->refcnt)) {
+		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		return -EBUSY;
+	}
+
+	/* Complain if we (somehow) got out of sync */
+	WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+	tmc_etb_disable_hw(drvdata);
+	/* Dissociate from monitored process. */
+	drvdata->pid = -1;
+	drvdata->mode = CS_MODE_DISABLED;
+
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	dev_dbg(&csdev->dev, "TMC-ETB/ETF disabled\n");
+	return 0;
+}
+
+static int tmc_enable_etf_link(struct coresight_device *csdev,
+			       int inport, int outport)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	bool first_enable = false;
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+	if (drvdata->reading) {
+		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		return -EBUSY;
+	}
+
+	if (atomic_read(&csdev->refcnt[0]) == 0) {
+		ret = tmc_etf_enable_hw(drvdata);
+		if (!ret) {
+			drvdata->mode = CS_MODE_SYSFS;
+			first_enable = true;
+		}
+	}
+	if (!ret)
+		atomic_inc(&csdev->refcnt[0]);
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	if (first_enable)
+		dev_dbg(&csdev->dev, "TMC-ETF enabled\n");
+	return ret;
+}
+
+static void tmc_disable_etf_link(struct coresight_device *csdev,
+				 int inport, int outport)
+{
+	unsigned long flags;
+	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	bool last_disable = false;
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+	if (drvdata->reading) {
+		spin_unlock_irqrestore(&drvdata->spinlock, flags);
+		return;
+	}
+
+	if (atomic_dec_return(&csdev->refcnt[0]) == 0) {
+		tmc_etf_disable_hw(drvdata);
+		drvdata->mode = CS_MODE_DISABLED;
+		last_disable = true;
+	}
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	if (last_disable)
+		dev_dbg(&csdev->dev, "TMC-ETF disabled\n");
+}
+
+static void *tmc_alloc_etf_buffer(struct coresight_device *csdev,
+				  struct perf_event *event, void **pages,
+				  int nr_pages, bool overwrite)
+{
+	int node;
+	struct cs_buffers *buf;
+
+	node = (event->cpu == -1) ? NUMA_NO_NODE : cpu_to_node(event->cpu);
+
+	/* Allocate memory structure for interaction with Perf */
+	buf = kzalloc_node(sizeof(struct cs_buffers), GFP_KERNEL, node);
+	if (!buf)
+		return NULL;
+
+	buf->pid = task_pid_nr(event->owner);
+	buf->snapshot = overwrite;
+	buf->nr_pages = nr_pages;
+	buf->data_pages = pages;
+
+	return buf;
+}
+
+static void tmc_free_etf_buffer(void *config)
+{
+	struct cs_buffers *buf = config;
+
+	kfree(buf);
+}
+
+static int tmc_set_etf_buffer(struct coresight_device *csdev,
+			      struct perf_output_handle *handle)
+{
+	int ret = 0;
+	unsigned long head;
+	struct cs_buffers *buf = etm_perf_sink_config(handle);
+
+	if (!buf)
+		return -EINVAL;
+
+	/* wrap head around to the amount of space we have */
+	head = handle->head & (((unsigned long)buf->nr_pages << PAGE_SHIFT) - 1);
+
+	/* find the page to write to */
+	buf->cur = head / PAGE_SIZE;
+
+	/* and offset within that page */
+	buf->offset = head % PAGE_SIZE;
+
+	local_set(&buf->data_size, 0);
+
+	return ret;
+}
+
+static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
+				  struct perf_output_handle *handle,
+				  void *sink_config)
+{
+	bool lost = false;
+	int i, cur;
+	const u32 *barrier;
+	u32 *buf_ptr;
+	u64 read_ptr, write_ptr;
+	u32 status;
+	unsigned long offset, to_read = 0, flags;
+	struct cs_buffers *buf = sink_config;
+	struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	if (!buf)
+		return 0;
+
+	/* This shouldn't happen */
+	if (WARN_ON_ONCE(drvdata->mode != CS_MODE_PERF))
+		return 0;
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+
+	/* Don't do anything if another tracer is using this sink */
+	if (atomic_read(csdev->refcnt) != 1)
+		goto out;
+
+	CS_UNLOCK(drvdata->base);
+
+	tmc_flush_and_stop(drvdata);
+
+	read_ptr = tmc_read_rrp(drvdata);
+	write_ptr = tmc_read_rwp(drvdata);
+
+	/*
+	 * Get a hold of the status register and see if a wrap around
+	 * has occurred.  If so adjust things accordingly.
+	 */
+	status = readl_relaxed(drvdata->base + TMC_STS);
+	if (status & TMC_STS_FULL) {
+		lost = true;
+		to_read = drvdata->size;
+	} else {
+		to_read = CIRC_CNT(write_ptr, read_ptr, drvdata->size);
+	}
+
+	/*
+	 * The TMC RAM buffer may be bigger than the space available in the
+	 * perf ring buffer (handle->size).  If so advance the RRP so that we
+	 * get the latest trace data.  In snapshot mode none of that matters
+	 * since we are expected to clobber stale data in favour of the latest
+	 * traces.
+	 */
+	if (!buf->snapshot && to_read > handle->size) {
+		u32 mask = tmc_get_memwidth_mask(drvdata);
+
+		/*
+		 * Make sure the new size is aligned in accordance with the
+		 * requirement explained in function tmc_get_memwidth_mask().
+		 */
+		to_read = handle->size & mask;
+		/* Move the RAM read pointer up */
+		read_ptr = (write_ptr + drvdata->size) - to_read;
+		/* Make sure we are still within our limits */
+		if (read_ptr > (drvdata->size - 1))
+			read_ptr -= drvdata->size;
+		/* Tell the HW */
+		tmc_write_rrp(drvdata, read_ptr);
+		lost = true;
+	}
+
+	/*
+	 * Don't set the TRUNCATED flag in snapshot mode because 1) the
+	 * captured buffer is expected to be truncated and 2) a full buffer
+	 * prevents the event from being re-enabled by the perf core,
+	 * resulting in stale data being send to user space.
+	 */
+	if (!buf->snapshot && lost)
+		perf_aux_output_flag(handle, PERF_AUX_FLAG_TRUNCATED);
+
+	cur = buf->cur;
+	offset = buf->offset;
+	barrier = coresight_barrier_pkt;
+
+	/* for every byte to read */
+	for (i = 0; i < to_read; i += 4) {
+		buf_ptr = buf->data_pages[cur] + offset;
+		*buf_ptr = readl_relaxed(drvdata->base + TMC_RRD);
+
+		if (lost && i < CORESIGHT_BARRIER_PKT_SIZE) {
+			*buf_ptr = *barrier;
+			barrier++;
+		}
+
+		offset += 4;
+		if (offset >= PAGE_SIZE) {
+			offset = 0;
+			cur++;
+			/* wrap around at the end of the buffer */
+			cur &= buf->nr_pages - 1;
+		}
+	}
+
+	/*
+	 * In snapshot mode we simply increment the head by the number of byte
+	 * that were written.  User space function  cs_etm_find_snapshot() will
+	 * figure out how many bytes to get from the AUX buffer based on the
+	 * position of the head.
+	 */
+	if (buf->snapshot)
+		handle->head += to_read;
+
+	CS_LOCK(drvdata->base);
+out:
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	return to_read;
+}
+
+static const struct coresight_ops_sink tmc_etf_sink_ops = {
+	.enable		= tmc_enable_etf_sink,
+	.disable	= tmc_disable_etf_sink,
+	.alloc_buffer	= tmc_alloc_etf_buffer,
+	.free_buffer	= tmc_free_etf_buffer,
+	.update_buffer	= tmc_update_etf_buffer,
+};
+
+static const struct coresight_ops_link tmc_etf_link_ops = {
+	.enable		= tmc_enable_etf_link,
+	.disable	= tmc_disable_etf_link,
+};
+
+const struct coresight_ops tmc_etb_cs_ops = {
+	.sink_ops	= &tmc_etf_sink_ops,
+};
+
+const struct coresight_ops tmc_etf_cs_ops = {
+	.sink_ops	= &tmc_etf_sink_ops,
+	.link_ops	= &tmc_etf_link_ops,
+};
+
+int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
+{
+	enum tmc_mode mode;
+	int ret = 0;
+	unsigned long flags;
+
+	/* config types are set a boot time and never change */
+	if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB &&
+			 drvdata->config_type != TMC_CONFIG_TYPE_ETF))
+		return -EINVAL;
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+
+	if (drvdata->reading) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	/* Don't interfere if operated from Perf */
+	if (drvdata->mode == CS_MODE_PERF) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* If drvdata::buf is NULL the trace data has been read already */
+	if (drvdata->buf == NULL) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Disable the TMC if need be */
+	if (drvdata->mode == CS_MODE_SYSFS) {
+		/* There is no point in reading a TMC in HW FIFO mode */
+		mode = readl_relaxed(drvdata->base + TMC_MODE);
+		if (mode != TMC_MODE_CIRCULAR_BUFFER) {
+			ret = -EINVAL;
+			goto out;
+		}
+		__tmc_etb_disable_hw(drvdata);
+	}
+
+	drvdata->reading = true;
+out:
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	return ret;
+}
+
+int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
+{
+	char *buf = NULL;
+	enum tmc_mode mode;
+	unsigned long flags;
+
+	/* config types are set a boot time and never change */
+	if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB &&
+			 drvdata->config_type != TMC_CONFIG_TYPE_ETF))
+		return -EINVAL;
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+
+	/* Re-enable the TMC if need be */
+	if (drvdata->mode == CS_MODE_SYSFS) {
+		/* There is no point in reading a TMC in HW FIFO mode */
+		mode = readl_relaxed(drvdata->base + TMC_MODE);
+		if (mode != TMC_MODE_CIRCULAR_BUFFER) {
+			spin_unlock_irqrestore(&drvdata->spinlock, flags);
+			return -EINVAL;
+		}
+		/*
+		 * The trace run will continue with the same allocated trace
+		 * buffer. As such zero-out the buffer so that we don't end
+		 * up with stale data.
+		 *
+		 * Since the tracer is still enabled drvdata::buf
+		 * can't be NULL.
+		 */
+		memset(drvdata->buf, 0, drvdata->size);
+		__tmc_etb_enable_hw(drvdata);
+	} else {
+		/*
+		 * The ETB/ETF is not tracing and the buffer was just read.
+		 * As such prepare to free the trace buffer.
+		 */
+		buf = drvdata->buf;
+		drvdata->buf = NULL;
+	}
+
+	drvdata->reading = false;
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+	/*
+	 * Free allocated memory outside of the spinlock.  There is no need
+	 * to assert the validity of 'buf' since calling kfree(NULL) is safe.
+	 */
+	kfree(buf);
+
+	return 0;
+}