coresight: etm3x: Allow etm3x to be built as a module

Allow to build coresight-etm3x as a module, for ease of development.

- Kconfig becomes a tristate, to allow =m
- append -core to source file name to allow module to
  be called coresight-etm3x by the Makefile
- add an etm_remove function, for module unload
- add a MODULE_DEVICE_TABLE for autoloading on boot
- delay advertising the per-cpu etmdrvdata
- protect etmdrvdata[] by modifying it on relevant CPU

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Reviewed-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Kim Phillips <kim.phillips@arm.com>
Signed-off-by: Tingwei Zhang <tingwei@codeaurora.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200928163513.70169-10-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 1026 insertions, 0 deletions

diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
new file mode 100644
index 000000000000..47f610b1c2b1
--- /dev/null
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -0,0 +1,1026 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2011-2012, The Linux Foundation. All rights reserved.
+ *
+ * Description: CoreSight Program Flow Trace driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/smp.h>
+#include <linux/sysfs.h>
+#include <linux/stat.h>
+#include <linux/pm_runtime.h>
+#include <linux/cpu.h>
+#include <linux/of.h>
+#include <linux/coresight.h>
+#include <linux/coresight-pmu.h>
+#include <linux/amba/bus.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/clk.h>
+#include <linux/perf_event.h>
+#include <asm/sections.h>
+
+#include "coresight-etm.h"
+#include "coresight-etm-perf.h"
+
+/*
+ * Not really modular but using module_param is the easiest way to
+ * remain consistent with existing use cases for now.
+ */
+static int boot_enable;
+module_param_named(boot_enable, boot_enable, int, S_IRUGO);
+
+static struct etm_drvdata *etmdrvdata[NR_CPUS];
+
+static enum cpuhp_state hp_online;
+
+/*
+ * Memory mapped writes to clear os lock are not supported on some processors
+ * and OS lock must be unlocked before any memory mapped access on such
+ * processors, otherwise memory mapped reads/writes will be invalid.
+ */
+static void etm_os_unlock(struct etm_drvdata *drvdata)
+{
+	/* Writing any value to ETMOSLAR unlocks the trace registers */
+	etm_writel(drvdata, 0x0, ETMOSLAR);
+	drvdata->os_unlock = true;
+	isb();
+}
+
+static void etm_set_pwrdwn(struct etm_drvdata *drvdata)
+{
+	u32 etmcr;
+
+	/* Ensure pending cp14 accesses complete before setting pwrdwn */
+	mb();
+	isb();
+	etmcr = etm_readl(drvdata, ETMCR);
+	etmcr |= ETMCR_PWD_DWN;
+	etm_writel(drvdata, etmcr, ETMCR);
+}
+
+static void etm_clr_pwrdwn(struct etm_drvdata *drvdata)
+{
+	u32 etmcr;
+
+	etmcr = etm_readl(drvdata, ETMCR);
+	etmcr &= ~ETMCR_PWD_DWN;
+	etm_writel(drvdata, etmcr, ETMCR);
+	/* Ensure pwrup completes before subsequent cp14 accesses */
+	mb();
+	isb();
+}
+
+static void etm_set_pwrup(struct etm_drvdata *drvdata)
+{
+	u32 etmpdcr;
+
+	etmpdcr = readl_relaxed(drvdata->base + ETMPDCR);
+	etmpdcr |= ETMPDCR_PWD_UP;
+	writel_relaxed(etmpdcr, drvdata->base + ETMPDCR);
+	/* Ensure pwrup completes before subsequent cp14 accesses */
+	mb();
+	isb();
+}
+
+static void etm_clr_pwrup(struct etm_drvdata *drvdata)
+{
+	u32 etmpdcr;
+
+	/* Ensure pending cp14 accesses complete before clearing pwrup */
+	mb();
+	isb();
+	etmpdcr = readl_relaxed(drvdata->base + ETMPDCR);
+	etmpdcr &= ~ETMPDCR_PWD_UP;
+	writel_relaxed(etmpdcr, drvdata->base + ETMPDCR);
+}
+
+/**
+ * coresight_timeout_etm - loop until a bit has changed to a specific state.
+ * @drvdata: etm's private data structure.
+ * @offset: address of a register, starting from @addr.
+ * @position: the position of the bit of interest.
+ * @value: the value the bit should have.
+ *
+ * Basically the same as @coresight_timeout except for the register access
+ * method where we have to account for CP14 configurations.
+
+ * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
+ * TIMEOUT_US has elapsed, which ever happens first.
+ */
+
+static int coresight_timeout_etm(struct etm_drvdata *drvdata, u32 offset,
+				  int position, int value)
+{
+	int i;
+	u32 val;
+
+	for (i = TIMEOUT_US; i > 0; i--) {
+		val = etm_readl(drvdata, offset);
+		/* Waiting on the bit to go from 0 to 1 */
+		if (value) {
+			if (val & BIT(position))
+				return 0;
+		/* Waiting on the bit to go from 1 to 0 */
+		} else {
+			if (!(val & BIT(position)))
+				return 0;
+		}
+
+		/*
+		 * Delay is arbitrary - the specification doesn't say how long
+		 * we are expected to wait.  Extra check required to make sure
+		 * we don't wait needlessly on the last iteration.
+		 */
+		if (i - 1)
+			udelay(1);
+	}
+
+	return -EAGAIN;
+}
+
+
+static void etm_set_prog(struct etm_drvdata *drvdata)
+{
+	u32 etmcr;
+
+	etmcr = etm_readl(drvdata, ETMCR);
+	etmcr |= ETMCR_ETM_PRG;
+	etm_writel(drvdata, etmcr, ETMCR);
+	/*
+	 * Recommended by spec for cp14 accesses to ensure etmcr write is
+	 * complete before polling etmsr
+	 */
+	isb();
+	if (coresight_timeout_etm(drvdata, ETMSR, ETMSR_PROG_BIT, 1)) {
+		dev_err(&drvdata->csdev->dev,
+			"%s: timeout observed when probing at offset %#x\n",
+			__func__, ETMSR);
+	}
+}
+
+static void etm_clr_prog(struct etm_drvdata *drvdata)
+{
+	u32 etmcr;
+
+	etmcr = etm_readl(drvdata, ETMCR);
+	etmcr &= ~ETMCR_ETM_PRG;
+	etm_writel(drvdata, etmcr, ETMCR);
+	/*
+	 * Recommended by spec for cp14 accesses to ensure etmcr write is
+	 * complete before polling etmsr
+	 */
+	isb();
+	if (coresight_timeout_etm(drvdata, ETMSR, ETMSR_PROG_BIT, 0)) {
+		dev_err(&drvdata->csdev->dev,
+			"%s: timeout observed when probing at offset %#x\n",
+			__func__, ETMSR);
+	}
+}
+
+void etm_set_default(struct etm_config *config)
+{
+	int i;
+
+	if (WARN_ON_ONCE(!config))
+		return;
+
+	/*
+	 * Taken verbatim from the TRM:
+	 *
+	 * To trace all memory:
+	 *  set bit [24] in register 0x009, the ETMTECR1, to 1
+	 *  set all other bits in register 0x009, the ETMTECR1, to 0
+	 *  set all bits in register 0x007, the ETMTECR2, to 0
+	 *  set register 0x008, the ETMTEEVR, to 0x6F (TRUE).
+	 */
+	config->enable_ctrl1 = BIT(24);
+	config->enable_ctrl2 = 0x0;
+	config->enable_event = ETM_HARD_WIRE_RES_A;
+
+	config->trigger_event = ETM_DEFAULT_EVENT_VAL;
+	config->enable_event = ETM_HARD_WIRE_RES_A;
+
+	config->seq_12_event = ETM_DEFAULT_EVENT_VAL;
+	config->seq_21_event = ETM_DEFAULT_EVENT_VAL;
+	config->seq_23_event = ETM_DEFAULT_EVENT_VAL;
+	config->seq_31_event = ETM_DEFAULT_EVENT_VAL;
+	config->seq_32_event = ETM_DEFAULT_EVENT_VAL;
+	config->seq_13_event = ETM_DEFAULT_EVENT_VAL;
+	config->timestamp_event = ETM_DEFAULT_EVENT_VAL;
+
+	for (i = 0; i < ETM_MAX_CNTR; i++) {
+		config->cntr_rld_val[i] = 0x0;
+		config->cntr_event[i] = ETM_DEFAULT_EVENT_VAL;
+		config->cntr_rld_event[i] = ETM_DEFAULT_EVENT_VAL;
+		config->cntr_val[i] = 0x0;
+	}
+
+	config->seq_curr_state = 0x0;
+	config->ctxid_idx = 0x0;
+	for (i = 0; i < ETM_MAX_CTXID_CMP; i++)
+		config->ctxid_pid[i] = 0x0;
+
+	config->ctxid_mask = 0x0;
+	/* Setting default to 1024 as per TRM recommendation */
+	config->sync_freq = 0x400;
+}
+
+void etm_config_trace_mode(struct etm_config *config)
+{
+	u32 flags, mode;
+
+	mode = config->mode;
+
+	mode &= (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER);
+
+	/* excluding kernel AND user space doesn't make sense */
+	if (mode == (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER))
+		return;
+
+	/* nothing to do if neither flags are set */
+	if (!(mode & ETM_MODE_EXCL_KERN) && !(mode & ETM_MODE_EXCL_USER))
+		return;
+
+	flags = (1 << 0 |	/* instruction execute */
+		 3 << 3 |	/* ARM instruction */
+		 0 << 5 |	/* No data value comparison */
+		 0 << 7 |	/* No exact mach */
+		 0 << 8);	/* Ignore context ID */
+
+	/* No need to worry about single address comparators. */
+	config->enable_ctrl2 = 0x0;
+
+	/* Bit 0 is address range comparator 1 */
+	config->enable_ctrl1 = ETMTECR1_ADDR_COMP_1;
+
+	/*
+	 * On ETMv3.5:
+	 * ETMACTRn[13,11] == Non-secure state comparison control
+	 * ETMACTRn[12,10] == Secure state comparison control
+	 *
+	 * b00 == Match in all modes in this state
+	 * b01 == Do not match in any more in this state
+	 * b10 == Match in all modes excepts user mode in this state
+	 * b11 == Match only in user mode in this state
+	 */
+
+	/* Tracing in secure mode is not supported at this time */
+	flags |= (0 << 12 | 1 << 10);
+
+	if (mode & ETM_MODE_EXCL_USER) {
+		/* exclude user, match all modes except user mode */
+		flags |= (1 << 13 | 0 << 11);
+	} else {
+		/* exclude kernel, match only in user mode */
+		flags |= (1 << 13 | 1 << 11);
+	}
+
+	/*
+	 * The ETMEEVR register is already set to "hard wire A".  As such
+	 * all there is to do is setup an address comparator that spans
+	 * the entire address range and configure the state and mode bits.
+	 */
+	config->addr_val[0] = (u32) 0x0;
+	config->addr_val[1] = (u32) ~0x0;
+	config->addr_acctype[0] = flags;
+	config->addr_acctype[1] = flags;
+	config->addr_type[0] = ETM_ADDR_TYPE_RANGE;
+	config->addr_type[1] = ETM_ADDR_TYPE_RANGE;
+}
+
+#define ETM3X_SUPPORTED_OPTIONS (ETMCR_CYC_ACC | \
+				 ETMCR_TIMESTAMP_EN | \
+				 ETMCR_RETURN_STACK)
+
+static int etm_parse_event_config(struct etm_drvdata *drvdata,
+				  struct perf_event *event)
+{
+	struct etm_config *config = &drvdata->config;
+	struct perf_event_attr *attr = &event->attr;
+
+	if (!attr)
+		return -EINVAL;
+
+	/* Clear configuration from previous run */
+	memset(config, 0, sizeof(struct etm_config));
+
+	if (attr->exclude_kernel)
+		config->mode = ETM_MODE_EXCL_KERN;
+
+	if (attr->exclude_user)
+		config->mode = ETM_MODE_EXCL_USER;
+
+	/* Always start from the default config */
+	etm_set_default(config);
+
+	/*
+	 * By default the tracers are configured to trace the whole address
+	 * range.  Narrow the field only if requested by user space.
+	 */
+	if (config->mode)
+		etm_config_trace_mode(config);
+
+	/*
+	 * At this time only cycle accurate, return stack  and timestamp
+	 * options are available.
+	 */
+	if (attr->config & ~ETM3X_SUPPORTED_OPTIONS)
+		return -EINVAL;
+
+	config->ctrl = attr->config;
+
+	/*
+	 * Possible to have cores with PTM (supports ret stack) and ETM
+	 * (never has ret stack) on the same SoC. So if we have a request
+	 * for return stack that can't be honoured on this core then
+	 * clear the bit - trace will still continue normally
+	 */
+	if ((config->ctrl & ETMCR_RETURN_STACK) &&
+	    !(drvdata->etmccer & ETMCCER_RETSTACK))
+		config->ctrl &= ~ETMCR_RETURN_STACK;
+
+	return 0;
+}
+
+static int etm_enable_hw(struct etm_drvdata *drvdata)
+{
+	int i, rc;
+	u32 etmcr;
+	struct etm_config *config = &drvdata->config;
+
+	CS_UNLOCK(drvdata->base);
+
+	rc = coresight_claim_device_unlocked(drvdata->base);
+	if (rc)
+		goto done;
+
+	/* Turn engine on */
+	etm_clr_pwrdwn(drvdata);
+	/* Apply power to trace registers */
+	etm_set_pwrup(drvdata);
+	/* Make sure all registers are accessible */
+	etm_os_unlock(drvdata);
+
+	etm_set_prog(drvdata);
+
+	etmcr = etm_readl(drvdata, ETMCR);
+	/* Clear setting from a previous run if need be */
+	etmcr &= ~ETM3X_SUPPORTED_OPTIONS;
+	etmcr |= drvdata->port_size;
+	etmcr |= ETMCR_ETM_EN;
+	etm_writel(drvdata, config->ctrl | etmcr, ETMCR);
+	etm_writel(drvdata, config->trigger_event, ETMTRIGGER);
+	etm_writel(drvdata, config->startstop_ctrl, ETMTSSCR);
+	etm_writel(drvdata, config->enable_event, ETMTEEVR);
+	etm_writel(drvdata, config->enable_ctrl1, ETMTECR1);
+	etm_writel(drvdata, config->fifofull_level, ETMFFLR);
+	for (i = 0; i < drvdata->nr_addr_cmp; i++) {
+		etm_writel(drvdata, config->addr_val[i], ETMACVRn(i));
+		etm_writel(drvdata, config->addr_acctype[i], ETMACTRn(i));
+	}
+	for (i = 0; i < drvdata->nr_cntr; i++) {
+		etm_writel(drvdata, config->cntr_rld_val[i], ETMCNTRLDVRn(i));
+		etm_writel(drvdata, config->cntr_event[i], ETMCNTENRn(i));
+		etm_writel(drvdata, config->cntr_rld_event[i],
+			   ETMCNTRLDEVRn(i));
+		etm_writel(drvdata, config->cntr_val[i], ETMCNTVRn(i));
+	}
+	etm_writel(drvdata, config->seq_12_event, ETMSQ12EVR);
+	etm_writel(drvdata, config->seq_21_event, ETMSQ21EVR);
+	etm_writel(drvdata, config->seq_23_event, ETMSQ23EVR);
+	etm_writel(drvdata, config->seq_31_event, ETMSQ31EVR);
+	etm_writel(drvdata, config->seq_32_event, ETMSQ32EVR);
+	etm_writel(drvdata, config->seq_13_event, ETMSQ13EVR);
+	etm_writel(drvdata, config->seq_curr_state, ETMSQR);
+	for (i = 0; i < drvdata->nr_ext_out; i++)
+		etm_writel(drvdata, ETM_DEFAULT_EVENT_VAL, ETMEXTOUTEVRn(i));
+	for (i = 0; i < drvdata->nr_ctxid_cmp; i++)
+		etm_writel(drvdata, config->ctxid_pid[i], ETMCIDCVRn(i));
+	etm_writel(drvdata, config->ctxid_mask, ETMCIDCMR);
+	etm_writel(drvdata, config->sync_freq, ETMSYNCFR);
+	/* No external input selected */
+	etm_writel(drvdata, 0x0, ETMEXTINSELR);
+	etm_writel(drvdata, config->timestamp_event, ETMTSEVR);
+	/* No auxiliary control selected */
+	etm_writel(drvdata, 0x0, ETMAUXCR);
+	etm_writel(drvdata, drvdata->traceid, ETMTRACEIDR);
+	/* No VMID comparator value selected */
+	etm_writel(drvdata, 0x0, ETMVMIDCVR);
+
+	etm_clr_prog(drvdata);
+
+done:
+	CS_LOCK(drvdata->base);
+
+	dev_dbg(&drvdata->csdev->dev, "cpu: %d enable smp call done: %d\n",
+		drvdata->cpu, rc);
+	return rc;
+}
+
+struct etm_enable_arg {
+	struct etm_drvdata *drvdata;
+	int rc;
+};
+
+static void etm_enable_hw_smp_call(void *info)
+{
+	struct etm_enable_arg *arg = info;
+
+	if (WARN_ON(!arg))
+		return;
+	arg->rc = etm_enable_hw(arg->drvdata);
+}
+
+static int etm_cpu_id(struct coresight_device *csdev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	return drvdata->cpu;
+}
+
+int etm_get_trace_id(struct etm_drvdata *drvdata)
+{
+	unsigned long flags;
+	int trace_id = -1;
+	struct device *etm_dev;
+
+	if (!drvdata)
+		goto out;
+
+	etm_dev = drvdata->csdev->dev.parent;
+	if (!local_read(&drvdata->mode))
+		return drvdata->traceid;
+
+	pm_runtime_get_sync(etm_dev);
+
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+
+	CS_UNLOCK(drvdata->base);
+	trace_id = (etm_readl(drvdata, ETMTRACEIDR) & ETM_TRACEID_MASK);
+	CS_LOCK(drvdata->base);
+
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	pm_runtime_put(etm_dev);
+
+out:
+	return trace_id;
+
+}
+
+static int etm_trace_id(struct coresight_device *csdev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	return etm_get_trace_id(drvdata);
+}
+
+static int etm_enable_perf(struct coresight_device *csdev,
+			   struct perf_event *event)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
+		return -EINVAL;
+
+	/* Configure the tracer based on the session's specifics */
+	etm_parse_event_config(drvdata, event);
+	/* And enable it */
+	return etm_enable_hw(drvdata);
+}
+
+static int etm_enable_sysfs(struct coresight_device *csdev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	struct etm_enable_arg arg = { };
+	int ret;
+
+	spin_lock(&drvdata->spinlock);
+
+	/*
+	 * Configure the ETM only if the CPU is online.  If it isn't online
+	 * hw configuration will take place on the local CPU during bring up.
+	 */
+	if (cpu_online(drvdata->cpu)) {
+		arg.drvdata = drvdata;
+		ret = smp_call_function_single(drvdata->cpu,
+					       etm_enable_hw_smp_call, &arg, 1);
+		if (!ret)
+			ret = arg.rc;
+		if (!ret)
+			drvdata->sticky_enable = true;
+	} else {
+		ret = -ENODEV;
+	}
+
+	spin_unlock(&drvdata->spinlock);
+
+	if (!ret)
+		dev_dbg(&csdev->dev, "ETM tracing enabled\n");
+	return ret;
+}
+
+static int etm_enable(struct coresight_device *csdev,
+		      struct perf_event *event, u32 mode)
+{
+	int ret;
+	u32 val;
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
+
+	/* Someone is already using the tracer */
+	if (val)
+		return -EBUSY;
+
+	switch (mode) {
+	case CS_MODE_SYSFS:
+		ret = etm_enable_sysfs(csdev);
+		break;
+	case CS_MODE_PERF:
+		ret = etm_enable_perf(csdev, event);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	/* The tracer didn't start */
+	if (ret)
+		local_set(&drvdata->mode, CS_MODE_DISABLED);
+
+	return ret;
+}
+
+static void etm_disable_hw(void *info)
+{
+	int i;
+	struct etm_drvdata *drvdata = info;
+	struct etm_config *config = &drvdata->config;
+
+	CS_UNLOCK(drvdata->base);
+	etm_set_prog(drvdata);
+
+	/* Read back sequencer and counters for post trace analysis */
+	config->seq_curr_state = (etm_readl(drvdata, ETMSQR) & ETM_SQR_MASK);
+
+	for (i = 0; i < drvdata->nr_cntr; i++)
+		config->cntr_val[i] = etm_readl(drvdata, ETMCNTVRn(i));
+
+	etm_set_pwrdwn(drvdata);
+	coresight_disclaim_device_unlocked(drvdata->base);
+
+	CS_LOCK(drvdata->base);
+
+	dev_dbg(&drvdata->csdev->dev,
+		"cpu: %d disable smp call done\n", drvdata->cpu);
+}
+
+static void etm_disable_perf(struct coresight_device *csdev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
+		return;
+
+	CS_UNLOCK(drvdata->base);
+
+	/* Setting the prog bit disables tracing immediately */
+	etm_set_prog(drvdata);
+
+	/*
+	 * There is no way to know when the tracer will be used again so
+	 * power down the tracer.
+	 */
+	etm_set_pwrdwn(drvdata);
+	coresight_disclaim_device_unlocked(drvdata->base);
+
+	CS_LOCK(drvdata->base);
+}
+
+static void etm_disable_sysfs(struct coresight_device *csdev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	/*
+	 * Taking hotplug lock here protects from clocks getting disabled
+	 * with tracing being left on (crash scenario) if user disable occurs
+	 * after cpu online mask indicates the cpu is offline but before the
+	 * DYING hotplug callback is serviced by the ETM driver.
+	 */
+	cpus_read_lock();
+	spin_lock(&drvdata->spinlock);
+
+	/*
+	 * Executing etm_disable_hw on the cpu whose ETM is being disabled
+	 * ensures that register writes occur when cpu is powered.
+	 */
+	smp_call_function_single(drvdata->cpu, etm_disable_hw, drvdata, 1);
+
+	spin_unlock(&drvdata->spinlock);
+	cpus_read_unlock();
+
+	dev_dbg(&csdev->dev, "ETM tracing disabled\n");
+}
+
+static void etm_disable(struct coresight_device *csdev,
+			struct perf_event *event)
+{
+	u32 mode;
+	struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+	/*
+	 * For as long as the tracer isn't disabled another entity can't
+	 * change its status.  As such we can read the status here without
+	 * fearing it will change under us.
+	 */
+	mode = local_read(&drvdata->mode);
+
+	switch (mode) {
+	case CS_MODE_DISABLED:
+		break;
+	case CS_MODE_SYSFS:
+		etm_disable_sysfs(csdev);
+		break;
+	case CS_MODE_PERF:
+		etm_disable_perf(csdev);
+		break;
+	default:
+		WARN_ON_ONCE(mode);
+		return;
+	}
+
+	if (mode)
+		local_set(&drvdata->mode, CS_MODE_DISABLED);
+}
+
+static const struct coresight_ops_source etm_source_ops = {
+	.cpu_id		= etm_cpu_id,
+	.trace_id	= etm_trace_id,
+	.enable		= etm_enable,
+	.disable	= etm_disable,
+};
+
+static const struct coresight_ops etm_cs_ops = {
+	.source_ops	= &etm_source_ops,
+};
+
+static int etm_online_cpu(unsigned int cpu)
+{
+	if (!etmdrvdata[cpu])
+		return 0;
+
+	if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
+		coresight_enable(etmdrvdata[cpu]->csdev);
+	return 0;
+}
+
+static int etm_starting_cpu(unsigned int cpu)
+{
+	if (!etmdrvdata[cpu])
+		return 0;
+
+	spin_lock(&etmdrvdata[cpu]->spinlock);
+	if (!etmdrvdata[cpu]->os_unlock) {
+		etm_os_unlock(etmdrvdata[cpu]);
+		etmdrvdata[cpu]->os_unlock = true;
+	}
+
+	if (local_read(&etmdrvdata[cpu]->mode))
+		etm_enable_hw(etmdrvdata[cpu]);
+	spin_unlock(&etmdrvdata[cpu]->spinlock);
+	return 0;
+}
+
+static int etm_dying_cpu(unsigned int cpu)
+{
+	if (!etmdrvdata[cpu])
+		return 0;
+
+	spin_lock(&etmdrvdata[cpu]->spinlock);
+	if (local_read(&etmdrvdata[cpu]->mode))
+		etm_disable_hw(etmdrvdata[cpu]);
+	spin_unlock(&etmdrvdata[cpu]->spinlock);
+	return 0;
+}
+
+static bool etm_arch_supported(u8 arch)
+{
+	switch (arch) {
+	case ETM_ARCH_V3_3:
+		break;
+	case ETM_ARCH_V3_5:
+		break;
+	case PFT_ARCH_V1_0:
+		break;
+	case PFT_ARCH_V1_1:
+		break;
+	default:
+		return false;
+	}
+	return true;
+}
+
+static void etm_init_arch_data(void *info)
+{
+	u32 etmidr;
+	u32 etmccr;
+	struct etm_drvdata *drvdata = info;
+
+	/* Make sure all registers are accessible */
+	etm_os_unlock(drvdata);
+
+	CS_UNLOCK(drvdata->base);
+
+	/* First dummy read */
+	(void)etm_readl(drvdata, ETMPDSR);
+	/* Provide power to ETM: ETMPDCR[3] == 1 */
+	etm_set_pwrup(drvdata);
+	/*
+	 * Clear power down bit since when this bit is set writes to
+	 * certain registers might be ignored.
+	 */
+	etm_clr_pwrdwn(drvdata);
+	/*
+	 * Set prog bit. It will be set from reset but this is included to
+	 * ensure it is set
+	 */
+	etm_set_prog(drvdata);
+
+	/* Find all capabilities */
+	etmidr = etm_readl(drvdata, ETMIDR);
+	drvdata->arch = BMVAL(etmidr, 4, 11);
+	drvdata->port_size = etm_readl(drvdata, ETMCR) & PORT_SIZE_MASK;
+
+	drvdata->etmccer = etm_readl(drvdata, ETMCCER);
+	etmccr = etm_readl(drvdata, ETMCCR);
+	drvdata->etmccr = etmccr;
+	drvdata->nr_addr_cmp = BMVAL(etmccr, 0, 3) * 2;
+	drvdata->nr_cntr = BMVAL(etmccr, 13, 15);
+	drvdata->nr_ext_inp = BMVAL(etmccr, 17, 19);
+	drvdata->nr_ext_out = BMVAL(etmccr, 20, 22);
+	drvdata->nr_ctxid_cmp = BMVAL(etmccr, 24, 25);
+
+	etm_set_pwrdwn(drvdata);
+	etm_clr_pwrup(drvdata);
+	CS_LOCK(drvdata->base);
+}
+
+static void etm_init_trace_id(struct etm_drvdata *drvdata)
+{
+	drvdata->traceid = coresight_get_trace_id(drvdata->cpu);
+}
+
+static int __init etm_hp_setup(void)
+{
+	int ret;
+
+	ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ARM_CORESIGHT_STARTING,
+						   "arm/coresight:starting",
+						   etm_starting_cpu, etm_dying_cpu);
+
+	if (ret)
+		return ret;
+
+	ret = cpuhp_setup_state_nocalls_cpuslocked(CPUHP_AP_ONLINE_DYN,
+						   "arm/coresight:online",
+						   etm_online_cpu, NULL);
+
+	/* HP dyn state ID returned in ret on success */
+	if (ret > 0) {
+		hp_online = ret;
+		return 0;
+	}
+
+	/* failed dyn state - remove others */
+	cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
+
+	return ret;
+}
+
+static void etm_hp_clear(void)
+{
+	cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
+	if (hp_online) {
+		cpuhp_remove_state_nocalls(hp_online);
+		hp_online = 0;
+	}
+}
+
+static int etm_probe(struct amba_device *adev, const struct amba_id *id)
+{
+	int ret;
+	void __iomem *base;
+	struct device *dev = &adev->dev;
+	struct coresight_platform_data *pdata = NULL;
+	struct etm_drvdata *drvdata;
+	struct resource *res = &adev->res;
+	struct coresight_desc desc = { 0 };
+
+	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	drvdata->use_cp14 = fwnode_property_read_bool(dev->fwnode, "arm,cp14");
+	dev_set_drvdata(dev, drvdata);
+
+	/* Validity for the resource is already checked by the AMBA core */
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	drvdata->base = base;
+
+	spin_lock_init(&drvdata->spinlock);
+
+	drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
+	if (!IS_ERR(drvdata->atclk)) {
+		ret = clk_prepare_enable(drvdata->atclk);
+		if (ret)
+			return ret;
+	}
+
+	drvdata->cpu = coresight_get_cpu(dev);
+	if (drvdata->cpu < 0)
+		return drvdata->cpu;
+
+	desc.name  = devm_kasprintf(dev, GFP_KERNEL, "etm%d", drvdata->cpu);
+	if (!desc.name)
+		return -ENOMEM;
+
+	if (smp_call_function_single(drvdata->cpu,
+				     etm_init_arch_data,  drvdata, 1))
+		dev_err(dev, "ETM arch init failed\n");
+
+	if (etm_arch_supported(drvdata->arch) == false)
+		return -EINVAL;
+
+	etm_init_trace_id(drvdata);
+	etm_set_default(&drvdata->config);
+
+	pdata = coresight_get_platform_data(dev);
+	if (IS_ERR(pdata))
+		return PTR_ERR(pdata);
+
+	adev->dev.platform_data = pdata;
+
+	desc.type = CORESIGHT_DEV_TYPE_SOURCE;
+	desc.subtype.source_subtype = CORESIGHT_DEV_SUBTYPE_SOURCE_PROC;
+	desc.ops = &etm_cs_ops;
+	desc.pdata = pdata;
+	desc.dev = dev;
+	desc.groups = coresight_etm_groups;
+	drvdata->csdev = coresight_register(&desc);
+	if (IS_ERR(drvdata->csdev))
+		return PTR_ERR(drvdata->csdev);
+
+	ret = etm_perf_symlink(drvdata->csdev, true);
+	if (ret) {
+		coresight_unregister(drvdata->csdev);
+		return ret;
+	}
+
+	etmdrvdata[drvdata->cpu] = drvdata;
+
+	pm_runtime_put(&adev->dev);
+	dev_info(&drvdata->csdev->dev,
+		 "%s initialized\n", (char *)coresight_get_uci_data(id));
+	if (boot_enable) {
+		coresight_enable(drvdata->csdev);
+		drvdata->boot_enable = true;
+	}
+
+	return 0;
+}
+
+static void __exit clear_etmdrvdata(void *info)
+{
+	int cpu = *(int *)info;
+
+	etmdrvdata[cpu] = NULL;
+}
+
+static int __exit etm_remove(struct amba_device *adev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(&adev->dev);
+
+	etm_perf_symlink(drvdata->csdev, false);
+
+	/*
+	 * Taking hotplug lock here to avoid racing between etm_remove and
+	 * CPU hotplug call backs.
+	 */
+	cpus_read_lock();
+	/*
+	 * The readers for etmdrvdata[] are CPU hotplug call backs
+	 * and PM notification call backs. Change etmdrvdata[i] on
+	 * CPU i ensures these call backs has consistent view
+	 * inside one call back function.
+	 */
+	if (smp_call_function_single(drvdata->cpu, clear_etmdrvdata, &drvdata->cpu, 1))
+		etmdrvdata[drvdata->cpu] = NULL;
+
+	cpus_read_unlock();
+
+	coresight_unregister(drvdata->csdev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int etm_runtime_suspend(struct device *dev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(dev);
+
+	if (drvdata && !IS_ERR(drvdata->atclk))
+		clk_disable_unprepare(drvdata->atclk);
+
+	return 0;
+}
+
+static int etm_runtime_resume(struct device *dev)
+{
+	struct etm_drvdata *drvdata = dev_get_drvdata(dev);
+
+	if (drvdata && !IS_ERR(drvdata->atclk))
+		clk_prepare_enable(drvdata->atclk);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops etm_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(etm_runtime_suspend, etm_runtime_resume, NULL)
+};
+
+static const struct amba_id etm_ids[] = {
+	/* ETM 3.3 */
+	CS_AMBA_ID_DATA(0x000bb921, "ETM 3.3"),
+	/* ETM 3.5 - Cortex-A5 */
+	CS_AMBA_ID_DATA(0x000bb955, "ETM 3.5"),
+	/* ETM 3.5 */
+	CS_AMBA_ID_DATA(0x000bb956, "ETM 3.5"),
+	/* PTM 1.0 */
+	CS_AMBA_ID_DATA(0x000bb950, "PTM 1.0"),
+	/* PTM 1.1 */
+	CS_AMBA_ID_DATA(0x000bb95f, "PTM 1.1"),
+	/* PTM 1.1 Qualcomm */
+	CS_AMBA_ID_DATA(0x000b006f, "PTM 1.1"),
+	{ 0, 0},
+};
+
+MODULE_DEVICE_TABLE(amba, etm_ids);
+
+static struct amba_driver etm_driver = {
+	.drv = {
+		.name	= "coresight-etm3x",
+		.owner	= THIS_MODULE,
+		.pm	= &etm_dev_pm_ops,
+		.suppress_bind_attrs = true,
+	},
+	.probe		= etm_probe,
+	.remove         = etm_remove,
+	.id_table	= etm_ids,
+};
+
+static int __init etm_init(void)
+{
+	int ret;
+
+	ret = etm_hp_setup();
+
+	/* etm_hp_setup() does its own cleanup - exit on error */
+	if (ret)
+		return ret;
+
+	ret = amba_driver_register(&etm_driver);
+	if (ret) {
+		pr_err("Error registering etm3x driver\n");
+		etm_hp_clear();
+	}
+
+	return ret;
+}
+
+static void __exit etm_exit(void)
+{
+	amba_driver_unregister(&etm_driver);
+	etm_hp_clear();
+}
+
+module_init(etm_init);
+module_exit(etm_exit);
+
+MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
+MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
+MODULE_DESCRIPTION("Arm CoreSight Program Flow Trace driver");
+MODULE_LICENSE("GPL v2");