coresight-etm4x: Adding CoreSight ETM4x driver

This driver manages the CoreSight ETMv4 (Embedded Trace Macrocell) IP block
to support HW assisted tracing on ARMv7 and ARMv8 architectures.
Signed-off-by: Pratik Patel <pratikp@codeaurora.org>
Signed-off-by: Kaixu Xia <xiakaixu@huawei.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-bus-coresight-devices-etm4x

+What:		/sys/bus/coresight/devices/<memory_map>.etm/enable_source
+Date:		April 2015
+KernelVersion:  4.01
+Contact:        Mathieu Poirier <mathieu.poirier@linaro.org>
+Description:	(RW) Enable/disable tracing on this specific trace entiry.
+		Enabling a source implies the source has been configured
+		properly and a sink has been identidifed for it.  The path
+		of coresight components linking the source to the sink is
+		configured and managed automatically by the coresight framework.
+
+What:		/sys/bus/coresight/devices/<memory_map>.etm/cpu
+Date:		April 2015
+KernelVersion:	4.01
+Contact:	Mathieu Poirier <mathieu.poirier@linaro.org>
+Description:	(R) The CPU this tracing entity is associated with.

drivers/hwtracing/coresight/Kconfig

@@ -58,4 +58,15 @@ config CORESIGHT_SOURCE_ETM3X
 	  which allows tracing the instructions that a processor is executing
 	  This is primarily useful for instruction level tracing.  Depending
 	  the ETM version data tracing may also be available.
+
+config CORESIGHT_SOURCE_ETM4X
+	bool "CoreSight Embedded Trace Macrocell 4.x driver"
+	depends on ARM64
+	select CORESIGHT_LINKS_AND_SINKS
+	help
+	  This driver provides support for the ETM4.x tracer module, tracing the
+	  instructions that a processor is executing. This is primarily useful
+	  for instruction level tracing. Depending on the implemented version
+	  data tracing may also be available.
+
 endif

drivers/hwtracing/coresight/Makefile

@@ -9,3 +9,4 @@ obj-$(CONFIG_CORESIGHT_SINK_ETBV10) += coresight-etb10.o
 obj-$(CONFIG_CORESIGHT_LINKS_AND_SINKS) += coresight-funnel.o \
 					   coresight-replicator.o
 obj-$(CONFIG_CORESIGHT_SOURCE_ETM3X) += coresight-etm3x.o coresight-etm-cp14.o
+obj-$(CONFIG_CORESIGHT_SOURCE_ETM4X) += coresight-etm4x.o

drivers/hwtracing/coresight/coresight-etm4x.c

+/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#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/clk.h>
+#include <linux/cpu.h>
+#include <linux/coresight.h>
+#include <linux/pm_wakeup.h>
+#include <linux/amba/bus.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+#include <linux/pm_runtime.h>
+#include <asm/sections.h>
+
+#include "coresight-etm4x.h"
+
+static int boot_enable;
+module_param_named(boot_enable, boot_enable, int, S_IRUGO);
+
+/* The number of ETMv4 currently registered */
+static int etm4_count;
+static struct etmv4_drvdata *etmdrvdata[NR_CPUS];
+
+static void etm4_os_unlock(void *info)
+{
+	struct etmv4_drvdata *drvdata = (struct etmv4_drvdata *)info;
+
+	/* Writing any value to ETMOSLAR unlocks the trace registers */
+	writel_relaxed(0x0, drvdata->base + TRCOSLAR);
+	isb();
+}
+
+static bool etm4_arch_supported(u8 arch)
+{
+	switch (arch) {
+	case ETM_ARCH_V4:
+		break;
+	default:
+		return false;
+	}
+	return true;
+}
+
+static int etm4_trace_id(struct coresight_device *csdev)
+{
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	unsigned long flags;
+	int trace_id = -1;
+
+	if (!drvdata->enable)
+		return drvdata->trcid;
+
+	pm_runtime_get_sync(drvdata->dev);
+	spin_lock_irqsave(&drvdata->spinlock, flags);
+
+	CS_UNLOCK(drvdata->base);
+	trace_id = readl_relaxed(drvdata->base + TRCTRACEIDR);
+	trace_id &= ETM_TRACEID_MASK;
+	CS_LOCK(drvdata->base);
+
+	spin_unlock_irqrestore(&drvdata->spinlock, flags);
+	pm_runtime_put(drvdata->dev);
+
+	return trace_id;
+}
+
+static void etm4_enable_hw(void *info)
+{
+	int i;
+	struct etmv4_drvdata *drvdata = info;
+
+	CS_UNLOCK(drvdata->base);
+
+	etm4_os_unlock(drvdata);
+
+	/* Disable the trace unit before programming trace registers */
+	writel_relaxed(0, drvdata->base + TRCPRGCTLR);
+
+	/* wait for TRCSTATR.IDLE to go up */
+	if (coresight_timeout(drvdata->base, TRCSTATR, TRCSTATR_IDLE_BIT, 1))
+		dev_err(drvdata->dev,
+			"timeout observed when probing at offset %#x\n",
+			TRCSTATR);
+
+	writel_relaxed(drvdata->pe_sel, drvdata->base + TRCPROCSELR);
+	writel_relaxed(drvdata->cfg, drvdata->base + TRCCONFIGR);
+	/* nothing specific implemented */
+	writel_relaxed(0x0, drvdata->base + TRCAUXCTLR);
+	writel_relaxed(drvdata->eventctrl0, drvdata->base + TRCEVENTCTL0R);
+	writel_relaxed(drvdata->eventctrl1, drvdata->base + TRCEVENTCTL1R);
+	writel_relaxed(drvdata->stall_ctrl, drvdata->base + TRCSTALLCTLR);
+	writel_relaxed(drvdata->ts_ctrl, drvdata->base + TRCTSCTLR);
+	writel_relaxed(drvdata->syncfreq, drvdata->base + TRCSYNCPR);
+	writel_relaxed(drvdata->ccctlr, drvdata->base + TRCCCCTLR);
+	writel_relaxed(drvdata->bb_ctrl, drvdata->base + TRCBBCTLR);
+	writel_relaxed(drvdata->trcid, drvdata->base + TRCTRACEIDR);
+	writel_relaxed(drvdata->vinst_ctrl, drvdata->base + TRCVICTLR);
+	writel_relaxed(drvdata->viiectlr, drvdata->base + TRCVIIECTLR);
+	writel_relaxed(drvdata->vissctlr,
+		       drvdata->base + TRCVISSCTLR);
+	writel_relaxed(drvdata->vipcssctlr,
+		       drvdata->base + TRCVIPCSSCTLR);
+	for (i = 0; i < drvdata->nrseqstate - 1; i++)
+		writel_relaxed(drvdata->seq_ctrl[i],
+			       drvdata->base + TRCSEQEVRn(i));
+	writel_relaxed(drvdata->seq_rst, drvdata->base + TRCSEQRSTEVR);
+	writel_relaxed(drvdata->seq_state, drvdata->base + TRCSEQSTR);
+	writel_relaxed(drvdata->ext_inp, drvdata->base + TRCEXTINSELR);
+	for (i = 0; i < drvdata->nr_cntr; i++) {
+		writel_relaxed(drvdata->cntrldvr[i],
+			       drvdata->base + TRCCNTRLDVRn(i));
+		writel_relaxed(drvdata->cntr_ctrl[i],
+			       drvdata->base + TRCCNTCTLRn(i));
+		writel_relaxed(drvdata->cntr_val[i],
+			       drvdata->base + TRCCNTVRn(i));
+	}
+	for (i = 0; i < drvdata->nr_resource; i++)
+		writel_relaxed(drvdata->res_ctrl[i],
+			       drvdata->base + TRCRSCTLRn(i));
+
+	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+		writel_relaxed(drvdata->ss_ctrl[i],
+			       drvdata->base + TRCSSCCRn(i));
+		writel_relaxed(drvdata->ss_status[i],
+			       drvdata->base + TRCSSCSRn(i));
+		writel_relaxed(drvdata->ss_pe_cmp[i],
+			       drvdata->base + TRCSSPCICRn(i));
+	}
+	for (i = 0; i < drvdata->nr_addr_cmp; i++) {
+		writeq_relaxed(drvdata->addr_val[i],
+			       drvdata->base + TRCACVRn(i));
+		writeq_relaxed(drvdata->addr_acc[i],
+			       drvdata->base + TRCACATRn(i));
+	}
+	for (i = 0; i < drvdata->numcidc; i++)
+		writeq_relaxed(drvdata->ctxid_val[i],
+			       drvdata->base + TRCCIDCVRn(i));
+	writel_relaxed(drvdata->ctxid_mask0, drvdata->base + TRCCIDCCTLR0);
+	writel_relaxed(drvdata->ctxid_mask1, drvdata->base + TRCCIDCCTLR1);
+
+	for (i = 0; i < drvdata->numvmidc; i++)
+		writeq_relaxed(drvdata->vmid_val[i],
+			       drvdata->base + TRCVMIDCVRn(i));
+	writel_relaxed(drvdata->vmid_mask0, drvdata->base + TRCVMIDCCTLR0);
+	writel_relaxed(drvdata->vmid_mask1, drvdata->base + TRCVMIDCCTLR1);
+
+	/* Enable the trace unit */
+	writel_relaxed(1, drvdata->base + TRCPRGCTLR);
+
+	/* wait for TRCSTATR.IDLE to go back down to '0' */
+	if (coresight_timeout(drvdata->base, TRCSTATR, TRCSTATR_IDLE_BIT, 0))
+		dev_err(drvdata->dev,
+			"timeout observed when probing at offset %#x\n",
+			TRCSTATR);
+
+	CS_LOCK(drvdata->base);
+
+	dev_dbg(drvdata->dev, "cpu: %d enable smp call done\n", drvdata->cpu);
+}
+
+static int etm4_enable(struct coresight_device *csdev)
+{
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+	int ret;
+
+	pm_runtime_get_sync(drvdata->dev);
+	spin_lock(&drvdata->spinlock);
+
+	/*
+	 * Executing etm4_enable_hw on the cpu whose ETM is being enabled
+	 * ensures that register writes occur when cpu is powered.
+	 */
+	ret = smp_call_function_single(drvdata->cpu,
+				       etm4_enable_hw, drvdata, 1);
+	if (ret)
+		goto err;
+	drvdata->enable = true;
+	drvdata->sticky_enable = true;
+
+	spin_unlock(&drvdata->spinlock);
+
+	dev_info(drvdata->dev, "ETM tracing enabled\n");
+	return 0;
+err:
+	spin_unlock(&drvdata->spinlock);
+	pm_runtime_put(drvdata->dev);
+	return ret;
+}
+
+static void etm4_disable_hw(void *info)
+{
+	u32 control;
+	struct etmv4_drvdata *drvdata = info;
+
+	CS_UNLOCK(drvdata->base);
+
+	control = readl_relaxed(drvdata->base + TRCPRGCTLR);
+
+	/* EN, bit[0] Trace unit enable bit */
+	control &= ~0x1;
+
+	/* make sure everything completes before disabling */
+	mb();
+	isb();
+	writel_relaxed(control, drvdata->base + TRCPRGCTLR);
+
+	CS_LOCK(drvdata->base);
+
+	dev_dbg(drvdata->dev, "cpu: %d disable smp call done\n", drvdata->cpu);
+}
+
+static void etm4_disable(struct coresight_device *csdev)
+{
+	struct etmv4_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.
+	 */
+	get_online_cpus();
+	spin_lock(&drvdata->spinlock);
+
+	/*
+	 * Executing etm4_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, etm4_disable_hw, drvdata, 1);
+	drvdata->enable = false;
+
+	spin_unlock(&drvdata->spinlock);
+	put_online_cpus();
+
+	pm_runtime_put(drvdata->dev);
+
+	dev_info(drvdata->dev, "ETM tracing disabled\n");
+}
+
+static const struct coresight_ops_source etm4_source_ops = {
+	.trace_id	= etm4_trace_id,
+	.enable		= etm4_enable,
+	.disable	= etm4_disable,
+};
+
+static const struct coresight_ops etm4_cs_ops = {
+	.source_ops	= &etm4_source_ops,
+};
+
+static ssize_t cpu_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	int val;
+	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+	val = drvdata->cpu;
+	return scnprintf(buf, PAGE_SIZE, "%d\n", val);
+
+}
+static DEVICE_ATTR_RO(cpu);
+
+static struct attribute *coresight_etmv4_attrs[] = {
+	&dev_attr_cpu.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(coresight_etmv4);
+
+static void etm4_init_arch_data(void *info)
+{
+	u32 etmidr0;
+	u32 etmidr1;
+	u32 etmidr2;
+	u32 etmidr3;
+	u32 etmidr4;
+	u32 etmidr5;
+	struct etmv4_drvdata *drvdata = info;
+
+	CS_UNLOCK(drvdata->base);
+
+	/* find all capabilities of the tracing unit */
+	etmidr0 = readl_relaxed(drvdata->base + TRCIDR0);
+
+	/* INSTP0, bits[2:1] P0 tracing support field */
+	if (BMVAL(etmidr0, 1, 1) && BMVAL(etmidr0, 2, 2))
+		drvdata->instrp0 = true;
+	else
+		drvdata->instrp0 = false;
+
+	/* TRCBB, bit[5] Branch broadcast tracing support bit */
+	if (BMVAL(etmidr0, 5, 5))
+		drvdata->trcbb = true;
+	else
+		drvdata->trcbb = false;
+
+	/* TRCCOND, bit[6] Conditional instruction tracing support bit */
+	if (BMVAL(etmidr0, 6, 6))
+		drvdata->trccond = true;
+	else
+		drvdata->trccond = false;
+
+	/* TRCCCI, bit[7] Cycle counting instruction bit */
+	if (BMVAL(etmidr0, 7, 7))
+		drvdata->trccci = true;
+	else
+		drvdata->trccci = false;
+
+	/* RETSTACK, bit[9] Return stack bit */
+	if (BMVAL(etmidr0, 9, 9))
+		drvdata->retstack = true;
+	else
+		drvdata->retstack = false;
+
+	/* NUMEVENT, bits[11:10] Number of events field */
+	drvdata->nr_event = BMVAL(etmidr0, 10, 11);
+	/* QSUPP, bits[16:15] Q element support field */
+	drvdata->q_support = BMVAL(etmidr0, 15, 16);
+	/* TSSIZE, bits[28:24] Global timestamp size field */
+	drvdata->ts_size = BMVAL(etmidr0, 24, 28);
+
+	/* base architecture of trace unit */
+	etmidr1 = readl_relaxed(drvdata->base + TRCIDR1);
+	/*
+	 * TRCARCHMIN, bits[7:4] architecture the minor version number
+	 * TRCARCHMAJ, bits[11:8] architecture major versin number
+	 */
+	drvdata->arch = BMVAL(etmidr1, 4, 11);
+
+	/* maximum size of resources */
+	etmidr2 = readl_relaxed(drvdata->base + TRCIDR2);
+	/* CIDSIZE, bits[9:5] Indicates the Context ID size */
+	drvdata->ctxid_size = BMVAL(etmidr2, 5, 9);
+	/* VMIDSIZE, bits[14:10] Indicates the VMID size */
+	drvdata->vmid_size = BMVAL(etmidr2, 10, 14);
+	/* CCSIZE, bits[28:25] size of the cycle counter in bits minus 12 */
+	drvdata->ccsize = BMVAL(etmidr2, 25, 28);
+
+	etmidr3 = readl_relaxed(drvdata->base + TRCIDR3);
+	/* CCITMIN, bits[11:0] minimum threshold value that can be programmed */
+	drvdata->ccitmin = BMVAL(etmidr3, 0, 11);
+	/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */
+	drvdata->s_ex_level = BMVAL(etmidr3, 16, 19);
+	/* EXLEVEL_NS, bits[23:20] Non-secure state instruction tracing */
+	drvdata->ns_ex_level = BMVAL(etmidr3, 20, 23);
+
+	/*
+	 * TRCERR, bit[24] whether a trace unit can trace a
+	 * system error exception.
+	 */
+	if (BMVAL(etmidr3, 24, 24))
+		drvdata->trc_error = true;
+	else
+		drvdata->trc_error = false;
+
+	/* SYNCPR, bit[25] implementation has a fixed synchronization period? */
+	if (BMVAL(etmidr3, 25, 25))
+		drvdata->syncpr = true;
+	else
+		drvdata->syncpr = false;
+
+	/* STALLCTL, bit[26] is stall control implemented? */
+	if (BMVAL(etmidr3, 26, 26))
+		drvdata->stallctl = true;
+	else
+		drvdata->stallctl = false;
+
+	/* SYSSTALL, bit[27] implementation can support stall control? */
+	if (BMVAL(etmidr3, 27, 27))
+		drvdata->sysstall = true;
+	else
+		drvdata->sysstall = false;
+
+	/* NUMPROC, bits[30:28] the number of PEs available for tracing */
+	drvdata->nr_pe = BMVAL(etmidr3, 28, 30);
+
+	/* NOOVERFLOW, bit[31] is trace overflow prevention supported */
+	if (BMVAL(etmidr3, 31, 31))
+		drvdata->nooverflow = true;
+	else
+		drvdata->nooverflow = false;
+
+	/* number of resources trace unit supports */
+	etmidr4 = readl_relaxed(drvdata->base + TRCIDR4);
+	/* NUMACPAIRS, bits[0:3] number of addr comparator pairs for tracing */
+	drvdata->nr_addr_cmp = BMVAL(etmidr4, 0, 3);
+	/* NUMPC, bits[15:12] number of PE comparator inputs for tracing */
+	drvdata->nr_pe_cmp = BMVAL(etmidr4, 12, 15);
+	/* NUMRSPAIR, bits[19:16] the number of resource pairs for tracing */
+	drvdata->nr_resource = BMVAL(etmidr4, 16, 19);
+	/*
+	 * NUMSSCC, bits[23:20] the number of single-shot
+	 * comparator control for tracing
+	 */
+	drvdata->nr_ss_cmp = BMVAL(etmidr4, 20, 23);
+	/* NUMCIDC, bits[27:24] number of Context ID comparators for tracing */
+	drvdata->numcidc = BMVAL(etmidr4, 24, 27);
+	/* NUMVMIDC, bits[31:28] number of VMID comparators for tracing */
+	drvdata->numvmidc = BMVAL(etmidr4, 28, 31);
+
+	etmidr5 = readl_relaxed(drvdata->base + TRCIDR5);
+	/* NUMEXTIN, bits[8:0] number of external inputs implemented */
+	drvdata->nr_ext_inp = BMVAL(etmidr5, 0, 8);
+	/* TRACEIDSIZE, bits[21:16] indicates the trace ID width */
+	drvdata->trcid_size = BMVAL(etmidr5, 16, 21);
+	/* ATBTRIG, bit[22] implementation can support ATB triggers? */
+	if (BMVAL(etmidr5, 22, 22))
+		drvdata->atbtrig = true;
+	else
+		drvdata->atbtrig = false;
+	/*
+	 * LPOVERRIDE, bit[23] implementation supports
+	 * low-power state override
+	 */
+	if (BMVAL(etmidr5, 23, 23))
+		drvdata->lpoverride = true;
+	else
+		drvdata->lpoverride = false;
+	/* NUMSEQSTATE, bits[27:25] number of sequencer states implemented */
+	drvdata->nrseqstate = BMVAL(etmidr5, 25, 27);
+	/* NUMCNTR, bits[30:28] number of counters available for tracing */
+	drvdata->nr_cntr = BMVAL(etmidr5, 28, 30);
+	CS_LOCK(drvdata->base);
+}
+
+static void etm4_init_default_data(struct etmv4_drvdata *drvdata)
+{
+	int i;
+
+	drvdata->pe_sel = 0x0;
+	drvdata->cfg = (ETMv4_MODE_CTXID | ETM_MODE_VMID |
+			ETMv4_MODE_TIMESTAMP | ETM_MODE_RETURNSTACK);
+
+	/* disable all events tracing */
+	drvdata->eventctrl0 = 0x0;
+	drvdata->eventctrl1 = 0x0;
+
+	/* disable stalling */
+	drvdata->stall_ctrl = 0x0;
+
+	/* disable timestamp event */
+	drvdata->ts_ctrl = 0x0;
+
+	/* enable trace synchronization every 4096 bytes for trace */
+	if (drvdata->syncpr == false)
+		drvdata->syncfreq = 0xC;
+
+	/*
+	 *  enable viewInst to trace everything with start-stop logic in
+	 *  started state
+	 */
+	drvdata->vinst_ctrl |= BIT(0);
+	/* set initial state of start-stop logic */
+	if (drvdata->nr_addr_cmp)
+		drvdata->vinst_ctrl |= BIT(9);
+
+	/* no address range filtering for ViewInst */
+	drvdata->viiectlr = 0x0;
+	/* no start-stop filtering for ViewInst */
+	drvdata->vissctlr = 0x0;
+
+	/* disable seq events */
+	for (i = 0; i < drvdata->nrseqstate-1; i++)
+		drvdata->seq_ctrl[i] = 0x0;
+	drvdata->seq_rst = 0x0;
+	drvdata->seq_state = 0x0;
+
+	/* disable external input events */
+	drvdata->ext_inp = 0x0;
+
+	for (i = 0; i < drvdata->nr_cntr; i++) {
+		drvdata->cntrldvr[i] = 0x0;
+		drvdata->cntr_ctrl[i] = 0x0;
+		drvdata->cntr_val[i] = 0x0;
+	}
+
+	for (i = 2; i < drvdata->nr_resource * 2; i++)
+		drvdata->res_ctrl[i] = 0x0;
+
+	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
+		drvdata->ss_ctrl[i] = 0x0;
+		drvdata->ss_pe_cmp[i] = 0x0;
+	}
+
+	if (drvdata->nr_addr_cmp >= 1) {
+		drvdata->addr_val[0] = (unsigned long)_stext;
+		drvdata->addr_val[1] = (unsigned long)_etext;
+		drvdata->addr_type[0] = ETM_ADDR_TYPE_RANGE;
+		drvdata->addr_type[1] = ETM_ADDR_TYPE_RANGE;
+	}
+
+	for (i = 0; i < drvdata->numcidc; i++)
+		drvdata->ctxid_val[i] = 0x0;
+	drvdata->ctxid_mask0 = 0x0;
+	drvdata->ctxid_mask1 = 0x0;
+
+	for (i = 0; i < drvdata->numvmidc; i++)
+		drvdata->vmid_val[i] = 0x0;
+	drvdata->vmid_mask0 = 0x0;
+	drvdata->vmid_mask1 = 0x0;
+
+	/*
+	 * A trace ID value of 0 is invalid, so let's start at some
+	 * random value that fits in 7 bits.  ETMv3.x has 0x10 so let's
+	 * start at 0x20.
+	 */
+	drvdata->trcid = 0x20 + drvdata->cpu;
+}
+
+static int etm4_cpu_callback(struct notifier_block *nfb, unsigned long action,
+			    void *hcpu)
+{
+	unsigned int cpu = (unsigned long)hcpu;
+
+	if (!etmdrvdata[cpu])
+		goto out;
+
+	switch (action & (~CPU_TASKS_FROZEN)) {
+	case CPU_STARTING:
+		spin_lock(&etmdrvdata[cpu]->spinlock);
+		if (!etmdrvdata[cpu]->os_unlock) {
+			etm4_os_unlock(etmdrvdata[cpu]);
+			etmdrvdata[cpu]->os_unlock = true;
+		}
+
+		if (etmdrvdata[cpu]->enable)
+			etm4_enable_hw(etmdrvdata[cpu]);
+		spin_unlock(&etmdrvdata[cpu]->spinlock);
+		break;
+
+	case CPU_ONLINE:
+		if (etmdrvdata[cpu]->boot_enable &&
+			!etmdrvdata[cpu]->sticky_enable)
+			coresight_enable(etmdrvdata[cpu]->csdev);
+		break;
+
+	case CPU_DYING:
+		spin_lock(&etmdrvdata[cpu]->spinlock);
+		if (etmdrvdata[cpu]->enable)
+			etm4_disable_hw(etmdrvdata[cpu]);
+		spin_unlock(&etmdrvdata[cpu]->spinlock);
+		break;
+	}
+out:
+	return NOTIFY_OK;
+}
+
+static struct notifier_block etm4_cpu_notifier = {
+	.notifier_call = etm4_cpu_callback,
+};
+
+static int etm4_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 etmv4_drvdata *drvdata;
+	struct resource *res = &adev->res;
+	struct coresight_desc *desc;
+	struct device_node *np = adev->dev.of_node;
+
+	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return -ENOMEM;
+
+	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
+	if (!drvdata)
+		return -ENOMEM;
+
+	if (np) {
+		pdata = of_get_coresight_platform_data(dev, np);
+		if (IS_ERR(pdata))
+			return PTR_ERR(pdata);
+		adev->dev.platform_data = pdata;
+	}
+
+	drvdata->dev = &adev->dev;
+	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->cpu = pdata ? pdata->cpu : 0;
+
+	get_online_cpus();
+	etmdrvdata[drvdata->cpu] = drvdata;
+
+	if (!smp_call_function_single(drvdata->cpu, etm4_os_unlock, drvdata, 1))
+		drvdata->os_unlock = true;
+
+	if (smp_call_function_single(drvdata->cpu,
+				etm4_init_arch_data,  drvdata, 1))
+		dev_err(dev, "ETM arch init failed\n");
+
+	if (!etm4_count++)
+		register_hotcpu_notifier(&etm4_cpu_notifier);
+
+	put_online_cpus();
+
+	if (etm4_arch_supported(drvdata->arch) == false) {
+		ret = -EINVAL;
+		goto err_arch_supported;
+	}
+	etm4_init_default_data(drvdata);
+
+	pm_runtime_put(&adev->dev);
+
+	desc->type = CORESIGHT_DEV_TYPE_SOURCE;
+	desc->subtype.source_subtype = CORESIGHT_DEV_SUBTYPE_SOURCE_PROC;
+	desc->ops = &etm4_cs_ops;
+	desc->pdata = pdata;
+	desc->dev = dev;
+	desc->groups = coresight_etmv4_groups;
+	drvdata->csdev = coresight_register(desc);
+	if (IS_ERR(drvdata->csdev)) {
+		ret = PTR_ERR(drvdata->csdev);
+		goto err_coresight_register;
+	}
+
+	dev_info(dev, "%s initialized\n", (char *)id->data);
+
+	if (boot_enable) {
+		coresight_enable(drvdata->csdev);
+		drvdata->boot_enable = true;
+	}
+
+	return 0;
+
+err_arch_supported:
+	pm_runtime_put(&adev->dev);
+err_coresight_register:
+	if (--etm4_count == 0)
+		unregister_hotcpu_notifier(&etm4_cpu_notifier);
+	return ret;
+}
+
+static int etm4_remove(struct amba_device *adev)
+{
+	struct etmv4_drvdata *drvdata = amba_get_drvdata(adev);
+
+	coresight_unregister(drvdata->csdev);
+	if (--etm4_count == 0)
+		unregister_hotcpu_notifier(&etm4_cpu_notifier);
+
+	return 0;
+}
+
+static struct amba_id etm4_ids[] = {
+	{       /* ETM 4.0 - Qualcomm */
+		.id	= 0x0003b95d,
+		.mask	= 0x0003ffff,
+		.data	= "ETM 4.0",
+	},
+	{       /* ETM 4.0 - Juno board */
+		.id	= 0x000bb95e,
+		.mask	= 0x000fffff,
+		.data	= "ETM 4.0",
+	},
+	{ 0, 0},
+};
+
+static struct amba_driver etm4x_driver = {
+	.drv = {
+		.name   = "coresight-etm4x",
+	},
+	.probe		= etm4_probe,
+	.remove		= etm4_remove,
+	.id_table	= etm4_ids,
+};
+
+module_amba_driver(etm4x_driver);

drivers/hwtracing/coresight/coresight-etm4x.h

+/* Copyright (c) 2014-2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _CORESIGHT_CORESIGHT_ETM_H
+#define _CORESIGHT_CORESIGHT_ETM_H
+
+#include <linux/spinlock.h>
+#include "coresight-priv.h"
+
+/*
+ * Device registers:
+ * 0x000 - 0x2FC: Trace		registers
+ * 0x300 - 0x314: Management	registers
+ * 0x318 - 0xEFC: Trace		registers
+ * 0xF00: Management		registers
+ * 0xFA0 - 0xFA4: Trace		registers
+ * 0xFA8 - 0xFFC: Management	registers
+ */
+/* Trace registers (0x000-0x2FC) */
+/* Main control and configuration registers */
+#define TRCPRGCTLR			0x004
+#define TRCPROCSELR			0x008
+#define TRCSTATR			0x00C
+#define TRCCONFIGR			0x010
+#define TRCAUXCTLR			0x018
+#define TRCEVENTCTL0R			0x020
+#define TRCEVENTCTL1R			0x024
+#define TRCSTALLCTLR			0x02C
+#define TRCTSCTLR			0x030
+#define TRCSYNCPR			0x034
+#define TRCCCCTLR			0x038
+#define TRCBBCTLR			0x03C
+#define TRCTRACEIDR			0x040
+#define TRCQCTLR			0x044
+/* Filtering control registers */
+#define TRCVICTLR			0x080
+#define TRCVIIECTLR			0x084
+#define TRCVISSCTLR			0x088
+#define TRCVIPCSSCTLR			0x08C
+#define TRCVDCTLR			0x0A0
+#define TRCVDSACCTLR			0x0A4
+#define TRCVDARCCTLR			0x0A8
+/* Derived resources registers */
+#define TRCSEQEVRn(n)			(0x100 + (n * 4))
+#define TRCSEQRSTEVR			0x118
+#define TRCSEQSTR			0x11C
+#define TRCEXTINSELR			0x120
+#define TRCCNTRLDVRn(n)			(0x140 + (n * 4))
+#define TRCCNTCTLRn(n)			(0x150 + (n * 4))
+#define TRCCNTVRn(n)			(0x160 + (n * 4))
+/* ID registers */
+#define TRCIDR8				0x180
+#define TRCIDR9				0x184
+#define TRCIDR10			0x188
+#define TRCIDR11			0x18C
+#define TRCIDR12			0x190
+#define TRCIDR13			0x194
+#define TRCIMSPEC0			0x1C0
+#define TRCIMSPECn(n)			(0x1C0 + (n * 4))
+#define TRCIDR0				0x1E0
+#define TRCIDR1				0x1E4
+#define TRCIDR2				0x1E8
+#define TRCIDR3				0x1EC
+#define TRCIDR4				0x1F0
+#define TRCIDR5				0x1F4
+#define TRCIDR6				0x1F8
+#define TRCIDR7				0x1FC
+/* Resource selection registers */
+#define TRCRSCTLRn(n)			(0x200 + (n * 4))
+/* Single-shot comparator registers */
+#define TRCSSCCRn(n)			(0x280 + (n * 4))
+#define TRCSSCSRn(n)			(0x2A0 + (n * 4))
+#define TRCSSPCICRn(n)			(0x2C0 + (n * 4))
+/* Management registers (0x300-0x314) */
+#define TRCOSLAR			0x300
+#define TRCOSLSR			0x304
+#define TRCPDCR				0x310
+#define TRCPDSR				0x314
+/* Trace registers (0x318-0xEFC) */
+/* Comparator registers */
+#define TRCACVRn(n)			(0x400 + (n * 8))
+#define TRCACATRn(n)			(0x480 + (n * 8))
+#define TRCDVCVRn(n)			(0x500 + (n * 16))
+#define TRCDVCMRn(n)			(0x580 + (n * 16))
+#define TRCCIDCVRn(n)			(0x600 + (n * 8))
+#define TRCVMIDCVRn(n)			(0x640 + (n * 8))
+#define TRCCIDCCTLR0			0x680
+#define TRCCIDCCTLR1			0x684
+#define TRCVMIDCCTLR0			0x688
+#define TRCVMIDCCTLR1			0x68C
+/* Management register (0xF00) */
+/* Integration control registers */
+#define TRCITCTRL			0xF00
+/* Trace registers (0xFA0-0xFA4) */
+/* Claim tag registers */
+#define TRCCLAIMSET			0xFA0
+#define TRCCLAIMCLR			0xFA4
+/* Management registers (0xFA8-0xFFC) */
+#define TRCDEVAFF0			0xFA8
+#define TRCDEVAFF1			0xFAC
+#define TRCLAR				0xFB0
+#define TRCLSR				0xFB4
+#define TRCAUTHSTATUS			0xFB8
+#define TRCDEVARCH			0xFBC
+#define TRCDEVID			0xFC8
+#define TRCDEVTYPE			0xFCC
+#define TRCPIDR4			0xFD0
+#define TRCPIDR5			0xFD4
+#define TRCPIDR6			0xFD8
+#define TRCPIDR7			0xFDC
+#define TRCPIDR0			0xFE0
+#define TRCPIDR1			0xFE4
+#define TRCPIDR2			0xFE8
+#define TRCPIDR3			0xFEC
+#define TRCCIDR0			0xFF0
+#define TRCCIDR1			0xFF4
+#define TRCCIDR2			0xFF8
+#define TRCCIDR3			0xFFC
+
+/* ETMv4 resources */
+#define ETM_MAX_NR_PE			8
+#define ETMv4_MAX_CNTR			4
+#define ETM_MAX_SEQ_STATES		4
+#define ETM_MAX_EXT_INP_SEL		4
+#define ETM_MAX_EXT_INP			256
+#define ETM_MAX_EXT_OUT			4
+#define ETM_MAX_SINGLE_ADDR_CMP		16
+#define ETM_MAX_ADDR_RANGE_CMP		(ETM_MAX_SINGLE_ADDR_CMP / 2)
+#define ETM_MAX_DATA_VAL_CMP		8
+#define ETMv4_MAX_CTXID_CMP		8
+#define ETM_MAX_VMID_CMP		8
+#define ETM_MAX_PE_CMP			8
+#define ETM_MAX_RES_SEL			16
+#define ETM_MAX_SS_CMP			8
+
+#define ETM_ARCH_V4			0x40
+#define ETMv4_SYNC_MASK			0x1F
+#define ETM_CYC_THRESHOLD_MASK		0xFFF
+#define ETMv4_EVENT_MASK		0xFF
+#define ETM_CNTR_MAX_VAL		0xFFFF
+#define ETM_TRACEID_MASK		0x3f
+
+/* ETMv4 programming modes */
+#define ETM_MODE_EXCLUDE		BIT(0)
+#define ETM_MODE_LOAD			BIT(1)
+#define ETM_MODE_STORE			BIT(2)
+#define ETM_MODE_LOAD_STORE		BIT(3)
+#define ETM_MODE_BB			BIT(4)
+#define ETMv4_MODE_CYCACC		BIT(5)
+#define ETMv4_MODE_CTXID		BIT(6)
+#define ETM_MODE_VMID			BIT(7)
+#define ETM_MODE_COND(val)		BMVAL(val, 8, 10)
+#define ETMv4_MODE_TIMESTAMP		BIT(11)
+#define ETM_MODE_RETURNSTACK		BIT(12)
+#define ETM_MODE_QELEM(val)		BMVAL(val, 13, 14)
+#define ETM_MODE_DATA_TRACE_ADDR	BIT(15)
+#define ETM_MODE_DATA_TRACE_VAL		BIT(16)
+#define ETM_MODE_ISTALL			BIT(17)
+#define ETM_MODE_DSTALL			BIT(18)
+#define ETM_MODE_ATB_TRIGGER		BIT(19)
+#define ETM_MODE_LPOVERRIDE		BIT(20)
+#define ETM_MODE_ISTALL_EN		BIT(21)
+#define ETM_MODE_DSTALL_EN		BIT(22)
+#define ETM_MODE_INSTPRIO		BIT(23)
+#define ETM_MODE_NOOVERFLOW		BIT(24)
+#define ETM_MODE_TRACE_RESET		BIT(25)
+#define ETM_MODE_TRACE_ERR		BIT(26)
+#define ETM_MODE_VIEWINST_STARTSTOP	BIT(27)
+#define ETMv4_MODE_ALL			0xFFFFFFF
+
+#define TRCSTATR_IDLE_BIT		0
+
+/**
+ * struct etm4_drvdata - specifics associated to an ETM component
+ * @base:       Memory mapped base address for this component.
+ * @dev:        The device entity associated to this component.
+ * @csdev:      Component vitals needed by the framework.
+ * @spinlock:   Only one at a time pls.
+ * @cpu:        The cpu this component is affined to.
+ * @arch:       ETM version number.
+ * @enable:	Is this ETM currently tracing.
+ * @sticky_enable: true if ETM base configuration has been done.
+ * @boot_enable:True if we should start tracing at boot time.
+ * @os_unlock:  True if access to management registers is allowed.
+ * @nr_pe:	The number of processing entity available for tracing.
+ * @nr_pe_cmp:	The number of processing entity comparator inputs that are
+ *		available for tracing.
+ * @nr_addr_cmp:Number of pairs of address comparators available
+ *		as found in ETMIDR4 0-3.
+ * @nr_cntr:    Number of counters as found in ETMIDR5 bit 28-30.
+ * @nr_ext_inp: Number of external input.
+ * @numcidc:	Number of contextID comparators.
+ * @numvmidc:	Number of VMID comparators.
+ * @nrseqstate: The number of sequencer states that are implemented.
+ * @nr_event:	Indicates how many events the trace unit support.
+ * @nr_resource:The number of resource selection pairs available for tracing.
+ * @nr_ss_cmp:	Number of single-shot comparator controls that are available.
+ * @mode:	Controls various modes supported by this ETM.
+ * @trcid:	value of the current ID for this component.
+ * @trcid_size: Indicates the trace ID width.
+ * @instrp0:	Tracing of load and store instructions
+ *		as P0 elements is supported.
+ * @trccond:	If the trace unit supports conditional
+ *		instruction tracing.
+ * @retstack:	Indicates if the implementation supports a return stack.
+ * @trc_error:	Whether a trace unit can trace a system
+ *		error exception.
+ * @atbtrig:	If the implementation can support ATB triggers
+ * @lpoverride:	If the implementation can support low-power state over.
+ * @pe_sel:	Controls which PE to trace.
+ * @cfg:	Controls the tracing options.
+ * @eventctrl0: Controls the tracing of arbitrary events.
+ * @eventctrl1: Controls the behavior of the events that @event_ctrl0 selects.
+ * @stallctl:	If functionality that prevents trace unit buffer overflows
+ *		is available.
+ * @sysstall:	Does the system support stall control of the PE?
+ * @nooverflow:	Indicate if overflow prevention is supported.
+ * @stall_ctrl:	Enables trace unit functionality that prevents trace
+ *		unit buffer overflows.
+ * @ts_size:	Global timestamp size field.
+ * @ts_ctrl:	Controls the insertion of global timestamps in the
+ *		trace streams.
+ * @syncpr:	Indicates if an implementation has a fixed
+ *		synchronization period.
+ * @syncfreq:	Controls how often trace synchronization requests occur.
+ * @trccci:	Indicates if the trace unit supports cycle counting
+ *		for instruction.
+ * @ccsize:	Indicates the size of the cycle counter in bits.
+ * @ccitmin:	minimum value that can be programmed in
+ *		the TRCCCCTLR register.
+ * @ccctlr:	Sets the threshold value for cycle counting.
+ * @trcbb:	Indicates if the trace unit supports branch broadcast tracing.
+ * @q_support:	Q element support characteristics.
+ * @vinst_ctrl:	Controls instruction trace filtering.
+ * @viiectlr:	Set or read, the address range comparators.
+ * @vissctlr:	Set, or read, the single address comparators that control the
+ *		ViewInst start-stop logic.
+ * @vipcssctlr:	Set, or read, which PE comparator inputs can control the
+ *		ViewInst start-stop logic.
+ * @seq_idx:	Sequencor index selector.
+ * @seq_ctrl:	Control for the sequencer state transition control register.
+ * @seq_rst:	Moves the sequencer to state 0 when a programmed event occurs.
+ * @seq_state:	Set, or read the sequencer state.
+ * @cntr_idx:	Counter index seletor.
+ * @cntrldvr:	Sets or returns the reload count value for a counter.
+ * @cntr_ctrl:	Controls the operation of a counter.
+ * @cntr_val:	Sets or returns the value for a counter.
+ * @res_idx:	Resource index selector.
+ * @res_ctrl:	Controls the selection of the resources in the trace unit.
+ * @ss_ctrl:	Controls the corresponding single-shot comparator resource.
+ * @ss_status:	The status of the corresponding single-shot comparator.
+ * @ss_pe_cmp:	Selects the PE comparator inputs for Single-shot control.
+ * @addr_idx:	Address comparator index selector.
+ * @addr_val:	Value for address comparator.
+ * @addr_acc:	Address comparator access type.
+ * @addr_type:	Current status of the comparator register.
+ * @ctxid_idx:	Context ID index selector.
+ * @ctxid_size:	Size of the context ID field to consider.
+ * @ctxid_val:	Value of the context ID comparator.
+ * @ctxid_mask0:Context ID comparator mask for comparator 0-3.
+ * @ctxid_mask1:Context ID comparator mask for comparator 4-7.
+ * @vmid_idx:	VM ID index selector.
+ * @vmid_size:	Size of the VM ID comparator to consider.
+ * @vmid_val:	Value of the VM ID comparator.
+ * @vmid_mask0:	VM ID comparator mask for comparator 0-3.
+ * @vmid_mask1:	VM ID comparator mask for comparator 4-7.
+ * @s_ex_level:	In secure state, indicates whether instruction tracing is
+ *		supported for the corresponding Exception level.
+ * @ns_ex_level:In non-secure state, indicates whether instruction tracing is
+ *		supported for the corresponding Exception level.
+ * @ext_inp:	External input selection.
+ */
+struct etmv4_drvdata {
+	void __iomem			*base;
+	struct device			*dev;
+	struct coresight_device		*csdev;
+	spinlock_t			spinlock;
+	int				cpu;
+	u8				arch;
+	bool				enable;
+	bool				sticky_enable;
+	bool				boot_enable;
+	bool				os_unlock;
+	u8				nr_pe;
+	u8				nr_pe_cmp;
+	u8				nr_addr_cmp;
+	u8				nr_cntr;
+	u8				nr_ext_inp;
+	u8				numcidc;
+	u8				numvmidc;
+	u8				nrseqstate;
+	u8				nr_event;
+	u8				nr_resource;
+	u8				nr_ss_cmp;
+	u32				mode;
+	u8				trcid;
+	u8				trcid_size;
+	bool				instrp0;
+	bool				trccond;
+	bool				retstack;
+	bool				trc_error;
+	bool				atbtrig;
+	bool				lpoverride;
+	u32				pe_sel;
+	u32				cfg;
+	u32				eventctrl0;
+	u32				eventctrl1;
+	bool				stallctl;
+	bool				sysstall;
+	bool				nooverflow;
+	u32				stall_ctrl;
+	u8				ts_size;
+	u32				ts_ctrl;
+	bool				syncpr;
+	u32				syncfreq;
+	bool				trccci;
+	u8				ccsize;
+	u8				ccitmin;
+	u32				ccctlr;
+	bool				trcbb;
+	u32				bb_ctrl;
+	bool				q_support;
+	u32				vinst_ctrl;
+	u32				viiectlr;
+	u32				vissctlr;
+	u32				vipcssctlr;
+	u8				seq_idx;
+	u32				seq_ctrl[ETM_MAX_SEQ_STATES];
+	u32				seq_rst;
+	u32				seq_state;
+	u8				cntr_idx;
+	u32				cntrldvr[ETMv4_MAX_CNTR];
+	u32				cntr_ctrl[ETMv4_MAX_CNTR];
+	u32				cntr_val[ETMv4_MAX_CNTR];
+	u8				res_idx;
+	u32				res_ctrl[ETM_MAX_RES_SEL];
+	u32				ss_ctrl[ETM_MAX_SS_CMP];
+	u32				ss_status[ETM_MAX_SS_CMP];
+	u32				ss_pe_cmp[ETM_MAX_SS_CMP];
+	u8				addr_idx;
+	u64				addr_val[ETM_MAX_SINGLE_ADDR_CMP];
+	u64				addr_acc[ETM_MAX_SINGLE_ADDR_CMP];
+	u8				addr_type[ETM_MAX_SINGLE_ADDR_CMP];
+	u8				ctxid_idx;
+	u8				ctxid_size;
+	u64				ctxid_val[ETMv4_MAX_CTXID_CMP];
+	u32				ctxid_mask0;
+	u32				ctxid_mask1;
+	u8				vmid_idx;
+	u8				vmid_size;
+	u64				vmid_val[ETM_MAX_VMID_CMP];
+	u32				vmid_mask0;
+	u32				vmid_mask1;
+	u8				s_ex_level;
+	u8				ns_ex_level;
+	u32				ext_inp;
+};
+
+/* Address comparator access types */
+enum etm_addr_acctype {
+	ETM_INSTR_ADDR,
+	ETM_DATA_LOAD_ADDR,
+	ETM_DATA_STORE_ADDR,
+	ETM_DATA_LOAD_STORE_ADDR,
+};
+
+/* Address comparator context types */
+enum etm_addr_ctxtype {
+	ETM_CTX_NONE,
+	ETM_CTX_CTXID,
+	ETM_CTX_VMID,
+	ETM_CTX_CTXID_VMID,
+};
+
+enum etm_addr_type {
+	ETM_ADDR_TYPE_NONE,
+	ETM_ADDR_TYPE_SINGLE,
+	ETM_ADDR_TYPE_RANGE,
+	ETM_ADDR_TYPE_START,
+	ETM_ADDR_TYPE_STOP,
+};
+#endif