xref: /linux/drivers/hwtracing/coresight/coresight-etm4x-core.c (revision 83bd89291f5cc866f60d32c34e268896c7ba8a3d)

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2014, The Linux Foundation. All rights reserved.
 */

#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/kvm_host.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/cpu_pm.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/perf_event.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/clk/clk-conf.h>

#include <asm/barrier.h>
#include <asm/sections.h>
#include <asm/sysreg.h>
#include <asm/local.h>
#include <asm/virt.h>

#include "coresight-etm4x.h"
#include "coresight-etm-perf.h"
#include "coresight-etm4x-cfg.h"
#include "coresight-self-hosted-trace.h"
#include "coresight-syscfg.h"
#include "coresight-trace-id.h"

static int boot_enable;
module_param(boot_enable, int, 0444);
MODULE_PARM_DESC(boot_enable, "Enable tracing on boot");

#define PARAM_PM_SAVE_FIRMWARE	  0 /* save self-hosted state as per firmware */
#define PARAM_PM_SAVE_NEVER	  1 /* never save any state */
#define PARAM_PM_SAVE_SELF_HOSTED 2 /* save self-hosted state only */

static int pm_save_enable = PARAM_PM_SAVE_FIRMWARE;
module_param(pm_save_enable, int, 0444);
MODULE_PARM_DESC(pm_save_enable,
	"Save/restore state on power down: 1 = never, 2 = self-hosted");

static struct etmv4_drvdata *etmdrvdata[NR_CPUS];
static void etm4_set_default_config(struct etmv4_config *config);
static int etm4_set_event_filters(struct etmv4_drvdata *drvdata,
				  struct perf_event *event);
static u64 etm4_get_access_type(struct etmv4_config *config);

static enum cpuhp_state hp_online;

struct etm4_init_arg {
	struct device		*dev;
	struct csdev_access	*csa;
};

static DEFINE_PER_CPU(struct etm4_init_arg *, delayed_probe);
static int etm4_probe_cpu(unsigned int cpu);

/*
 * Check if TRCSSPCICRn(i) is implemented for a given instance.
 *
 * TRCSSPCICRn is implemented only if :
 *	TRCSSPCICR<n> is present only if all of the following are true:
 *		TRCIDR4.NUMSSCC > n.
 *		TRCIDR4.NUMPC > 0b0000 .
 *		TRCSSCSR<n>.PC == 0b1
 */
static bool etm4x_sspcicrn_present(struct etmv4_drvdata *drvdata, int n)
{
	return (n < drvdata->nr_ss_cmp) &&
	       drvdata->nr_pe &&
	       (drvdata->config.ss_status[n] & TRCSSCSRn_PC);
}

u64 etm4x_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
{
	u64 res = 0;

	switch (offset) {
	ETM4x_READ_SYSREG_CASES(res)
	default :
		pr_warn_ratelimited("etm4x: trying to read unsupported register @%x\n",
			 offset);
	}

	if (!_relaxed)
		__io_ar(res);	/* Imitate the !relaxed I/O helpers */

	return res;
}

void etm4x_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
{
	if (!_relaxed)
		__io_bw();	/* Imitate the !relaxed I/O helpers */
	if (!_64bit)
		val &= GENMASK(31, 0);

	switch (offset) {
	ETM4x_WRITE_SYSREG_CASES(val)
	default :
		pr_warn_ratelimited("etm4x: trying to write to unsupported register @%x\n",
			offset);
	}
}

static u64 ete_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
{
	u64 res = 0;

	switch (offset) {
	ETE_READ_CASES(res)
	default :
		pr_warn_ratelimited("ete: trying to read unsupported register @%x\n",
				    offset);
	}

	if (!_relaxed)
		__io_ar(res);	/* Imitate the !relaxed I/O helpers */

	return res;
}

static void ete_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
{
	if (!_relaxed)
		__io_bw();	/* Imitate the !relaxed I/O helpers */
	if (!_64bit)
		val &= GENMASK(31, 0);

	switch (offset) {
	ETE_WRITE_CASES(val)
	default :
		pr_warn_ratelimited("ete: trying to write to unsupported register @%x\n",
				    offset);
	}
}

static void etm_detect_os_lock(struct etmv4_drvdata *drvdata,
			       struct csdev_access *csa)
{
	u32 oslsr = etm4x_relaxed_read32(csa, TRCOSLSR);

	drvdata->os_lock_model = ETM_OSLSR_OSLM(oslsr);
}

static void etm_write_os_lock(struct etmv4_drvdata *drvdata,
			      struct csdev_access *csa, u32 val)
{
	val = !!val;

	switch (drvdata->os_lock_model) {
	case ETM_OSLOCK_PRESENT:
		etm4x_relaxed_write32(csa, val, TRCOSLAR);
		break;
	case ETM_OSLOCK_PE:
		write_sysreg_s(val, SYS_OSLAR_EL1);
		break;
	default:
		pr_warn_once("CPU%d: Unsupported Trace OSLock model: %x\n",
			     smp_processor_id(), drvdata->os_lock_model);
		fallthrough;
	case ETM_OSLOCK_NI:
		return;
	}
	isb();
}

static void etm4_os_unlock_csa(struct etmv4_drvdata *drvdata,
				      struct csdev_access *csa)
{
	WARN_ON(drvdata->cpu != smp_processor_id());

	/* Writing 0 to OS Lock unlocks the trace unit registers */
	etm_write_os_lock(drvdata, csa, 0x0);
	drvdata->os_unlock = true;
}

static void etm4_os_unlock(struct etmv4_drvdata *drvdata)
{
	if (!WARN_ON(!drvdata->csdev))
		etm4_os_unlock_csa(drvdata, &drvdata->csdev->access);
}

static void etm4_os_lock(struct etmv4_drvdata *drvdata)
{
	if (WARN_ON(!drvdata->csdev))
		return;
	/* Writing 0x1 to OS Lock locks the trace registers */
	etm_write_os_lock(drvdata, &drvdata->csdev->access, 0x1);
	drvdata->os_unlock = false;
}

static void etm4_cs_lock(struct etmv4_drvdata *drvdata,
			 struct csdev_access *csa)
{
	/* Software Lock is only accessible via memory mapped interface */
	if (csa->io_mem)
		CS_LOCK(csa->base);
}

static void etm4_cs_unlock(struct etmv4_drvdata *drvdata,
			   struct csdev_access *csa)
{
	if (csa->io_mem)
		CS_UNLOCK(csa->base);
}

static int etm4_cpu_id(struct coresight_device *csdev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	return drvdata->cpu;
}

void etm4_release_trace_id(struct etmv4_drvdata *drvdata)
{
	coresight_trace_id_put_cpu_id(drvdata->cpu);
}

struct etm4_enable_arg {
	struct etmv4_drvdata *drvdata;
	int rc;
};

/*
 * etm4x_prohibit_trace - Prohibit the CPU from tracing at all ELs.
 * When the CPU supports FEAT_TRF, we could move the ETM to a trace
 * prohibited state by filtering the Exception levels via TRFCR_EL1.
 */
static void etm4x_prohibit_trace(struct etmv4_drvdata *drvdata)
{
	u64 trfcr;

	/* If the CPU doesn't support FEAT_TRF, nothing to do */
	if (!drvdata->trfcr)
		return;

	trfcr = drvdata->trfcr & ~(TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE);

	write_trfcr(trfcr);
	kvm_tracing_set_el1_configuration(trfcr);
}

static u64 etm4x_get_kern_user_filter(struct etmv4_drvdata *drvdata)
{
	u64 trfcr = drvdata->trfcr;

	if (drvdata->config.mode & ETM_MODE_EXCL_KERN)
		trfcr &= ~TRFCR_EL1_ExTRE;
	if (drvdata->config.mode & ETM_MODE_EXCL_USER)
		trfcr &= ~TRFCR_EL1_E0TRE;

	return trfcr;
}

/*
 * etm4x_allow_trace - Allow CPU tracing in the respective ELs,
 * as configured by the drvdata->config.mode for the current
 * session. Even though we have TRCVICTLR bits to filter the
 * trace in the ELs, it doesn't prevent the ETM from generating
 * a packet (e.g, TraceInfo) that might contain the addresses from
 * the excluded levels. Thus we use the additional controls provided
 * via the Trace Filtering controls (FEAT_TRF) to make sure no trace
 * is generated for the excluded ELs.
 */
static void etm4x_allow_trace(struct etmv4_drvdata *drvdata)
{
	u64 trfcr, guest_trfcr;

	/* If the CPU doesn't support FEAT_TRF, nothing to do */
	if (!drvdata->trfcr)
		return;

	if (drvdata->config.mode & ETM_MODE_EXCL_HOST)
		trfcr = drvdata->trfcr & ~(TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE);
	else
		trfcr = etm4x_get_kern_user_filter(drvdata);

	write_trfcr(trfcr);

	/* Set filters for guests and pass to KVM */
	if (drvdata->config.mode & ETM_MODE_EXCL_GUEST)
		guest_trfcr = drvdata->trfcr & ~(TRFCR_EL1_ExTRE | TRFCR_EL1_E0TRE);
	else
		guest_trfcr = etm4x_get_kern_user_filter(drvdata);

	/* TRFCR_EL1 doesn't have CX so mask it out. */
	guest_trfcr &= ~TRFCR_EL2_CX;
	kvm_tracing_set_el1_configuration(guest_trfcr);
}

#ifdef CONFIG_ETM4X_IMPDEF_FEATURE

#define HISI_HIP08_AMBA_ID		0x000b6d01
#define ETM4_AMBA_MASK			0xfffff
#define HISI_HIP08_CORE_COMMIT_MASK	0x3000
#define HISI_HIP08_CORE_COMMIT_SHIFT	12
#define HISI_HIP08_CORE_COMMIT_FULL	0b00
#define HISI_HIP08_CORE_COMMIT_LVL_1	0b01
#define HISI_HIP08_CORE_COMMIT_REG	sys_reg(3, 1, 15, 2, 5)

struct etm4_arch_features {
	void (*arch_callback)(bool enable);
};

static bool etm4_hisi_match_pid(unsigned int id)
{
	return (id & ETM4_AMBA_MASK) == HISI_HIP08_AMBA_ID;
}

static void etm4_hisi_config_core_commit(bool enable)
{
	u8 commit = enable ? HISI_HIP08_CORE_COMMIT_LVL_1 :
		    HISI_HIP08_CORE_COMMIT_FULL;
	u64 val;

	/*
	 * bit 12 and 13 of HISI_HIP08_CORE_COMMIT_REG are used together
	 * to set core-commit, 2'b00 means cpu is at full speed, 2'b01,
	 * 2'b10, 2'b11 mean reduce pipeline speed, and 2'b01 means level-1
	 * speed(minimun value). So bit 12 and 13 should be cleared together.
	 */
	val = read_sysreg_s(HISI_HIP08_CORE_COMMIT_REG);
	val &= ~HISI_HIP08_CORE_COMMIT_MASK;
	val |= commit << HISI_HIP08_CORE_COMMIT_SHIFT;
	write_sysreg_s(val, HISI_HIP08_CORE_COMMIT_REG);
}

static struct etm4_arch_features etm4_features[] = {
	[ETM4_IMPDEF_HISI_CORE_COMMIT] = {
		.arch_callback = etm4_hisi_config_core_commit,
	},
	{},
};

static void etm4_enable_arch_specific(struct etmv4_drvdata *drvdata)
{
	struct etm4_arch_features *ftr;
	int bit;

	for_each_set_bit(bit, drvdata->arch_features, ETM4_IMPDEF_FEATURE_MAX) {
		ftr = &etm4_features[bit];

		if (ftr->arch_callback)
			ftr->arch_callback(true);
	}
}

static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
{
	struct etm4_arch_features *ftr;
	int bit;

	for_each_set_bit(bit, drvdata->arch_features, ETM4_IMPDEF_FEATURE_MAX) {
		ftr = &etm4_features[bit];

		if (ftr->arch_callback)
			ftr->arch_callback(false);
	}
}

static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
				     struct csdev_access *csa)
{
	/*
	 * TRCPIDR* registers are not required for ETMs with system
	 * instructions. They must be identified by the MIDR+REVIDRs.
	 * Skip the TRCPID checks for now.
	 */
	if (!csa->io_mem)
		return;

	if (etm4_hisi_match_pid(coresight_get_pid(csa)))
		set_bit(ETM4_IMPDEF_HISI_CORE_COMMIT, drvdata->arch_features);
}
#else
static void etm4_enable_arch_specific(struct etmv4_drvdata *drvdata)
{
}

static void etm4_disable_arch_specific(struct etmv4_drvdata *drvdata)
{
}

static void etm4_check_arch_features(struct etmv4_drvdata *drvdata,
				     struct csdev_access *csa)
{
}
#endif /* CONFIG_ETM4X_IMPDEF_FEATURE */

static void etm4x_sys_ins_barrier(struct csdev_access *csa, u32 offset, int pos, int val)
{
	if (!csa->io_mem)
		isb();
}

/*
 * etm4x_wait_status: Poll for TRCSTATR.<pos> == <val>. While using system
 * instruction to access the trace unit, each access must be separated by a
 * synchronization barrier. See ARM IHI0064H.b section "4.3.7 Synchronization of
 * register updates", for system instructions section, in "Notes":
 *
 *   "In particular, whenever disabling or enabling the trace unit, a poll of
 *    TRCSTATR needs explicit synchronization between each read of TRCSTATR"
 */
static int etm4x_wait_status(struct csdev_access *csa, int pos, int val)
{
	if (!csa->io_mem)
		return coresight_timeout_action(csa, TRCSTATR, pos, val,
						etm4x_sys_ins_barrier);
	return coresight_timeout(csa, TRCSTATR, pos, val);
}

static int etm4_enable_trace_unit(struct etmv4_drvdata *drvdata)
{
	struct coresight_device *csdev = drvdata->csdev;
	struct device *etm_dev = &csdev->dev;
	struct csdev_access *csa = &csdev->access;

	/*
	 * ETE mandates that the TRCRSR is written to before
	 * enabling it.
	 */
	if (etm4x_is_ete(drvdata))
		etm4x_relaxed_write32(csa, TRCRSR_TA, TRCRSR);

	etm4x_allow_trace(drvdata);

	/*
	 * According to software usage PKLXF in Arm ARM (ARM DDI 0487 L.a),
	 * execute a Context synchronization event to guarantee the trace unit
	 * will observe the new values of the System registers.
	 */
	if (!csa->io_mem)
		isb();

	/* Enable the trace unit */
	etm4x_relaxed_write32(csa, 1, TRCPRGCTLR);

	/*
	 * As recommended by section 4.3.7 ("Synchronization when using system
	 * instructions to progrom the trace unit") of ARM IHI 0064H.b, the
	 * self-hosted trace analyzer must perform a Context synchronization
	 * event between writing to the TRCPRGCTLR and reading the TRCSTATR.
	 */
	if (!csa->io_mem)
		isb();

	/* wait for TRCSTATR.IDLE to go back down to '0' */
	if (etm4x_wait_status(csa, TRCSTATR_IDLE_BIT, 0)) {
		dev_err(etm_dev,
			"timeout while waiting for Idle Trace Status\n");
		return -ETIME;
	}

	/*
	 * As recommended in section 4.3.7 (Synchronization of register updates)
	 * of ARM IHI 0064H.b, the self-hosted trace analyzer always executes an
	 * ISB instruction after programming the trace unit registers.
	 *
	 * For the memory-mapped interface, the registers are mapped as Device
	 * type (Device-nGnRE). Reading back the value of any register in the
	 * trace unit ensures that all writes have completed. Therefore, polling
	 * on TRCSTATR guarantees that the writing TRCPRGCTLR is complete, and
	 * no explicit dsb() is required at here.
	 */
	isb();

	return 0;
}

static int etm4_enable_hw(struct etmv4_drvdata *drvdata)
{
	int i, rc;
	struct etmv4_config *config = &drvdata->config;
	struct coresight_device *csdev = drvdata->csdev;
	struct device *etm_dev = &csdev->dev;
	struct csdev_access *csa = &csdev->access;


	etm4_cs_unlock(drvdata, csa);
	etm4_enable_arch_specific(drvdata);

	etm4_os_unlock(drvdata);

	rc = coresight_claim_device_unlocked(csdev);
	if (rc)
		goto done;

	/* Disable the trace unit before programming trace registers */
	etm4x_relaxed_write32(csa, 0, TRCPRGCTLR);

	/*
	 * If we use system instructions, we need to synchronize the
	 * write to the TRCPRGCTLR, before accessing the TRCSTATR.
	 * See ARM IHI0064F, section
	 * "4.3.7 Synchronization of register updates"
	 */
	if (!csa->io_mem)
		isb();

	/* wait for TRCSTATR.IDLE to go up */
	if (etm4x_wait_status(csa, TRCSTATR_IDLE_BIT, 1))
		dev_err(etm_dev,
			"timeout while waiting for Idle Trace Status\n");
	if (drvdata->nr_pe)
		etm4x_relaxed_write32(csa, config->pe_sel, TRCPROCSELR);
	etm4x_relaxed_write32(csa, config->cfg, TRCCONFIGR);
	/* nothing specific implemented */
	etm4x_relaxed_write32(csa, 0x0, TRCAUXCTLR);
	etm4x_relaxed_write32(csa, config->eventctrl0, TRCEVENTCTL0R);
	etm4x_relaxed_write32(csa, config->eventctrl1, TRCEVENTCTL1R);
	if (drvdata->stallctl)
		etm4x_relaxed_write32(csa, config->stall_ctrl, TRCSTALLCTLR);
	etm4x_relaxed_write32(csa, config->ts_ctrl, TRCTSCTLR);
	etm4x_relaxed_write32(csa, config->syncfreq, TRCSYNCPR);
	etm4x_relaxed_write32(csa, config->ccctlr, TRCCCCTLR);
	etm4x_relaxed_write32(csa, config->bb_ctrl, TRCBBCTLR);
	etm4x_relaxed_write32(csa, drvdata->trcid, TRCTRACEIDR);
	etm4x_relaxed_write32(csa, config->vinst_ctrl, TRCVICTLR);
	etm4x_relaxed_write32(csa, config->viiectlr, TRCVIIECTLR);
	etm4x_relaxed_write32(csa, config->vissctlr, TRCVISSCTLR);
	if (drvdata->nr_pe_cmp)
		etm4x_relaxed_write32(csa, config->vipcssctlr, TRCVIPCSSCTLR);
	for (i = 0; i < drvdata->nrseqstate - 1; i++)
		etm4x_relaxed_write32(csa, config->seq_ctrl[i], TRCSEQEVRn(i));
	if (drvdata->nrseqstate) {
		etm4x_relaxed_write32(csa, config->seq_rst, TRCSEQRSTEVR);
		etm4x_relaxed_write32(csa, config->seq_state, TRCSEQSTR);
	}
	if (drvdata->numextinsel)
		etm4x_relaxed_write32(csa, config->ext_inp, TRCEXTINSELR);
	for (i = 0; i < drvdata->nr_cntr; i++) {
		etm4x_relaxed_write32(csa, config->cntrldvr[i], TRCCNTRLDVRn(i));
		etm4x_relaxed_write32(csa, config->cntr_ctrl[i], TRCCNTCTLRn(i));
		etm4x_relaxed_write32(csa, config->cntr_val[i], TRCCNTVRn(i));
	}

	/*
	 * Resource selector pair 0 is always implemented and reserved.  As
	 * such start at 2.
	 */
	for (i = 2; i < drvdata->nr_resource * 2; i++)
		etm4x_relaxed_write32(csa, config->res_ctrl[i], TRCRSCTLRn(i));

	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
		/* always clear status bit on restart if using single-shot */
		if (config->ss_ctrl[i] || config->ss_pe_cmp[i])
			config->ss_status[i] &= ~TRCSSCSRn_STATUS;
		etm4x_relaxed_write32(csa, config->ss_ctrl[i], TRCSSCCRn(i));
		etm4x_relaxed_write32(csa, config->ss_status[i], TRCSSCSRn(i));
		if (etm4x_sspcicrn_present(drvdata, i))
			etm4x_relaxed_write32(csa, config->ss_pe_cmp[i], TRCSSPCICRn(i));
	}
	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
		etm4x_relaxed_write64(csa, config->addr_val[i], TRCACVRn(i));
		etm4x_relaxed_write64(csa, config->addr_acc[i], TRCACATRn(i));
	}
	for (i = 0; i < drvdata->numcidc; i++)
		etm4x_relaxed_write64(csa, config->ctxid_pid[i], TRCCIDCVRn(i));
	etm4x_relaxed_write32(csa, config->ctxid_mask0, TRCCIDCCTLR0);
	if (drvdata->numcidc > 4)
		etm4x_relaxed_write32(csa, config->ctxid_mask1, TRCCIDCCTLR1);

	for (i = 0; i < drvdata->numvmidc; i++)
		etm4x_relaxed_write64(csa, config->vmid_val[i], TRCVMIDCVRn(i));
	etm4x_relaxed_write32(csa, config->vmid_mask0, TRCVMIDCCTLR0);
	if (drvdata->numvmidc > 4)
		etm4x_relaxed_write32(csa, config->vmid_mask1, TRCVMIDCCTLR1);

	if (!drvdata->skip_power_up) {
		u32 trcpdcr = etm4x_relaxed_read32(csa, TRCPDCR);

		/*
		 * Request to keep the trace unit powered and also
		 * emulation of powerdown
		 */
		etm4x_relaxed_write32(csa, trcpdcr | TRCPDCR_PU, TRCPDCR);
	}

	if (!drvdata->paused)
		rc = etm4_enable_trace_unit(drvdata);
done:
	etm4_cs_lock(drvdata, csa);

	dev_dbg(etm_dev, "cpu: %d enable smp call done: %d\n",
		drvdata->cpu, rc);
	return rc;
}

static void etm4_enable_sysfs_smp_call(void *info)
{
	struct etm4_enable_arg *arg = info;
	struct coresight_device *csdev;

	if (WARN_ON(!arg))
		return;

	csdev = arg->drvdata->csdev;
	if (!coresight_take_mode(csdev, CS_MODE_SYSFS)) {
		/* Someone is already using the tracer */
		arg->rc = -EBUSY;
		return;
	}

	arg->rc = etm4_enable_hw(arg->drvdata);

	/* The tracer didn't start */
	if (arg->rc)
		coresight_set_mode(csdev, CS_MODE_DISABLED);
}

/*
 * The goal of function etm4_config_timestamp_event() is to configure a
 * counter that will tell the tracer to emit a timestamp packet when it
 * reaches zero.  This is done in order to get a more fine grained idea
 * of when instructions are executed so that they can be correlated
 * with execution on other CPUs.
 *
 * To do this the counter itself is configured to self reload and
 * TRCRSCTLR1 (always true) used to get the counter to decrement.  From
 * there a resource selector is configured with the counter and the
 * timestamp control register to use the resource selector to trigger the
 * event that will insert a timestamp packet in the stream.
 */
static int etm4_config_timestamp_event(struct etmv4_drvdata *drvdata)
{
	int ctridx, ret = -EINVAL;
	int counter, rselector;
	u32 val = 0;
	struct etmv4_config *config = &drvdata->config;

	/* No point in trying if we don't have at least one counter */
	if (!drvdata->nr_cntr)
		goto out;

	/* Find a counter that hasn't been initialised */
	for (ctridx = 0; ctridx < drvdata->nr_cntr; ctridx++)
		if (config->cntr_val[ctridx] == 0)
			break;

	/* All the counters have been configured already, bail out */
	if (ctridx == drvdata->nr_cntr) {
		pr_debug("%s: no available counter found\n", __func__);
		ret = -ENOSPC;
		goto out;
	}

	/*
	 * Searching for an available resource selector to use, starting at
	 * '2' since every implementation has at least 2 resource selector.
	 * ETMIDR4 gives the number of resource selector _pairs_,
	 * hence multiply by 2.
	 */
	for (rselector = 2; rselector < drvdata->nr_resource * 2; rselector++)
		if (!config->res_ctrl[rselector])
			break;

	if (rselector == drvdata->nr_resource * 2) {
		pr_debug("%s: no available resource selector found\n",
			 __func__);
		ret = -ENOSPC;
		goto out;
	}

	/* Remember what counter we used */
	counter = 1 << ctridx;

	/*
	 * Initialise original and reload counter value to the smallest
	 * possible value in order to get as much precision as we can.
	 */
	config->cntr_val[ctridx] = 1;
	config->cntrldvr[ctridx] = 1;

	/* Set the trace counter control register */
	val =  0x1 << 16	|  /* Bit 16, reload counter automatically */
	       0x0 << 7		|  /* Select single resource selector */
	       0x1;		   /* Resource selector 1, i.e always true */

	config->cntr_ctrl[ctridx] = val;

	val = 0x2 << 16		| /* Group 0b0010 - Counter and sequencers */
	      counter << 0;	  /* Counter to use */

	config->res_ctrl[rselector] = val;

	val = 0x0 << 7		| /* Select single resource selector */
	      rselector;	  /* Resource selector */

	config->ts_ctrl = val;

	ret = 0;
out:
	return ret;
}

static int etm4_parse_event_config(struct coresight_device *csdev,
				   struct perf_event *event)
{
	int ret = 0;
	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
	struct etmv4_config *config = &drvdata->config;
	struct perf_event_attr *attr = &event->attr;
	unsigned long cfg_hash;
	int preset, cc_threshold;

	/* Clear configuration from previous run */
	memset(config, 0, sizeof(struct etmv4_config));

	if (attr->exclude_kernel)
		config->mode = ETM_MODE_EXCL_KERN;

	if (attr->exclude_user)
		config->mode = ETM_MODE_EXCL_USER;

	if (attr->exclude_host)
		config->mode |= ETM_MODE_EXCL_HOST;

	if (attr->exclude_guest)
		config->mode |= ETM_MODE_EXCL_GUEST;

	/* Always start from the default config */
	etm4_set_default_config(config);

	/* Configure filters specified on the perf cmd line, if any. */
	ret = etm4_set_event_filters(drvdata, event);
	if (ret)
		goto out;

	/* Go from generic option to ETMv4 specifics */
	if (attr->config & BIT(ETM_OPT_CYCACC)) {
		config->cfg |= TRCCONFIGR_CCI;
		/* TRM: Must program this for cycacc to work */
		cc_threshold = attr->config3 & ETM_CYC_THRESHOLD_MASK;
		if (!cc_threshold)
			cc_threshold = ETM_CYC_THRESHOLD_DEFAULT;
		if (cc_threshold < drvdata->ccitmin)
			cc_threshold = drvdata->ccitmin;
		config->ccctlr = cc_threshold;
	}
	if (attr->config & BIT(ETM_OPT_TS)) {
		/*
		 * Configure timestamps to be emitted at regular intervals in
		 * order to correlate instructions executed on different CPUs
		 * (CPU-wide trace scenarios).
		 */
		ret = etm4_config_timestamp_event(drvdata);

		/*
		 * No need to go further if timestamp intervals can't
		 * be configured.
		 */
		if (ret)
			goto out;

		/* bit[11], Global timestamp tracing bit */
		config->cfg |= TRCCONFIGR_TS;
	}

	/* Only trace contextID when runs in root PID namespace */
	if ((attr->config & BIT(ETM_OPT_CTXTID)) &&
	    task_is_in_init_pid_ns(current))
		/* bit[6], Context ID tracing bit */
		config->cfg |= TRCCONFIGR_CID;

	/*
	 * If set bit ETM_OPT_CTXTID2 in perf config, this asks to trace VMID
	 * for recording CONTEXTIDR_EL2.  Do not enable VMID tracing if the
	 * kernel is not running in EL2.
	 */
	if (attr->config & BIT(ETM_OPT_CTXTID2)) {
		if (!is_kernel_in_hyp_mode()) {
			ret = -EINVAL;
			goto out;
		}
		/* Only trace virtual contextID when runs in root PID namespace */
		if (task_is_in_init_pid_ns(current))
			config->cfg |= TRCCONFIGR_VMID | TRCCONFIGR_VMIDOPT;
	}

	/* return stack - enable if selected and supported */
	if ((attr->config & BIT(ETM_OPT_RETSTK)) && drvdata->retstack)
		/* bit[12], Return stack enable bit */
		config->cfg |= TRCCONFIGR_RS;

	/*
	 * Set any selected configuration and preset.
	 *
	 * This extracts the values of PMU_FORMAT_ATTR(configid) and PMU_FORMAT_ATTR(preset)
	 * in the perf attributes defined in coresight-etm-perf.c.
	 * configid uses bits 63:32 of attr->config2, preset uses bits 3:0 of attr->config.
	 * A zero configid means no configuration active, preset = 0 means no preset selected.
	 */
	if (attr->config2 & GENMASK_ULL(63, 32)) {
		cfg_hash = (u32)(attr->config2 >> 32);
		preset = attr->config & 0xF;
		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
	}

	/* branch broadcast - enable if selected and supported */
	if (attr->config & BIT(ETM_OPT_BRANCH_BROADCAST)) {
		if (!drvdata->trcbb) {
			/*
			 * Missing BB support could cause silent decode errors
			 * so fail to open if it's not supported.
			 */
			ret = -EINVAL;
			goto out;
		} else {
			config->cfg |= BIT(ETM4_CFG_BIT_BB);
		}
	}

out:
	return ret;
}

static int etm4_enable_perf(struct coresight_device *csdev,
			    struct perf_event *event,
			    struct coresight_path *path)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
	int ret;

	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
		return -EINVAL;

	if (!coresight_take_mode(csdev, CS_MODE_PERF))
		return -EBUSY;

	/* Configure the tracer based on the session's specifics */
	ret = etm4_parse_event_config(csdev, event);
	if (ret)
		goto out;

	drvdata->trcid = path->trace_id;

	/* Populate pause state */
	drvdata->paused = !!READ_ONCE(event->hw.aux_paused);

	/* And enable it */
	ret = etm4_enable_hw(drvdata);

out:
	/* Failed to start tracer; roll back to DISABLED mode */
	if (ret)
		coresight_set_mode(csdev, CS_MODE_DISABLED);
	return ret;
}

static int etm4_enable_sysfs(struct coresight_device *csdev, struct coresight_path *path)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
	struct etm4_enable_arg arg = { };
	unsigned long cfg_hash;
	int ret, preset;

	/* enable any config activated by configfs */
	cscfg_config_sysfs_get_active_cfg(&cfg_hash, &preset);
	if (cfg_hash) {
		ret = cscfg_csdev_enable_active_config(csdev, cfg_hash, preset);
		if (ret)
			return ret;
	}

	raw_spin_lock(&drvdata->spinlock);

	drvdata->trcid = path->trace_id;

	/* Tracer will never be paused in sysfs mode */
	drvdata->paused = false;

	/*
	 * Executing etm4_enable_hw on the cpu whose ETM is being enabled
	 * ensures that register writes occur when cpu is powered.
	 */
	arg.drvdata = drvdata;
	ret = smp_call_function_single(drvdata->cpu,
				       etm4_enable_sysfs_smp_call, &arg, 1);
	if (!ret)
		ret = arg.rc;
	if (!ret)
		drvdata->sticky_enable = true;

	if (ret)
		etm4_release_trace_id(drvdata);

	raw_spin_unlock(&drvdata->spinlock);

	if (!ret)
		dev_dbg(&csdev->dev, "ETM tracing enabled\n");
	return ret;
}

static int etm4_enable(struct coresight_device *csdev, struct perf_event *event,
		       enum cs_mode mode, struct coresight_path *path)
{
	int ret;

	switch (mode) {
	case CS_MODE_SYSFS:
		ret = etm4_enable_sysfs(csdev, path);
		break;
	case CS_MODE_PERF:
		ret = etm4_enable_perf(csdev, event, path);
		break;
	default:
		ret = -EINVAL;
	}

	return ret;
}

static void etm4_disable_trace_unit(struct etmv4_drvdata *drvdata)
{
	u32 control;
	struct coresight_device *csdev = drvdata->csdev;
	struct device *etm_dev = &csdev->dev;
	struct csdev_access *csa = &csdev->access;

	control = etm4x_relaxed_read32(csa, TRCPRGCTLR);

	/* EN, bit[0] Trace unit enable bit */
	control &= ~0x1;

	/*
	 * If the CPU supports v8.4 Trace filter Control,
	 * set the ETM to trace prohibited region.
	 */
	etm4x_prohibit_trace(drvdata);
	/*
	 * Prevent being speculative at the point of disabling the trace unit,
	 * as recommended by section 7.3.77 ("TRCVICTLR, ViewInst Main Control
	 * Register, SSTATUS") of ARM IHI 0064D
	 */
	dsb(sy);
	/*
	 * According to software usage VKHHY in Arm ARM (ARM DDI 0487 L.a),
	 * execute a Context synchronization event to guarantee no new
	 * program-flow trace is generated.
	 */
	isb();
	/* Trace synchronization barrier, is a nop if not supported */
	tsb_csync();
	etm4x_relaxed_write32(csa, control, TRCPRGCTLR);

	/*
	 * As recommended by section 4.3.7 ("Synchronization when using system
	 * instructions to progrom the trace unit") of ARM IHI 0064H.b, the
	 * self-hosted trace analyzer must perform a Context synchronization
	 * event between writing to the TRCPRGCTLR and reading the TRCSTATR.
	 */
	if (!csa->io_mem)
		isb();

	/* wait for TRCSTATR.PMSTABLE to go to '1' */
	if (etm4x_wait_status(csa, TRCSTATR_PMSTABLE_BIT, 1))
		dev_err(etm_dev,
			"timeout while waiting for PM stable Trace Status\n");
	/*
	 * As recommended in section 4.3.7 (Synchronization of register updates)
	 * of ARM IHI 0064H.b, the self-hosted trace analyzer always executes an
	 * ISB instruction after programming the trace unit registers.
	 *
	 * For the memory-mapped interface, the registers are mapped as Device
	 * type (Device-nGnRE). Reading back the value of any register in the
	 * trace unit ensures that all writes have completed. Therefore, polling
	 * on TRCSTATR guarantees that the writing TRCPRGCTLR is complete, and
	 * no explicit dsb() is required at here.
	 */
	isb();
}

static void etm4_disable_hw(struct etmv4_drvdata *drvdata)
{
	u32 control;
	struct etmv4_config *config = &drvdata->config;
	struct coresight_device *csdev = drvdata->csdev;
	struct csdev_access *csa = &csdev->access;
	int i;

	etm4_cs_unlock(drvdata, csa);
	etm4_disable_arch_specific(drvdata);

	if (!drvdata->skip_power_up) {
		/* power can be removed from the trace unit now */
		control = etm4x_relaxed_read32(csa, TRCPDCR);
		control &= ~TRCPDCR_PU;
		etm4x_relaxed_write32(csa, control, TRCPDCR);
	}

	etm4_disable_trace_unit(drvdata);

	/* read the status of the single shot comparators */
	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
		config->ss_status[i] =
			etm4x_relaxed_read32(csa, TRCSSCSRn(i));
	}

	/* read back the current counter values */
	for (i = 0; i < drvdata->nr_cntr; i++) {
		config->cntr_val[i] =
			etm4x_relaxed_read32(csa, TRCCNTVRn(i));
	}

	coresight_disclaim_device_unlocked(csdev);
	etm4_cs_lock(drvdata, csa);

	dev_dbg(&drvdata->csdev->dev,
		"cpu: %d disable smp call done\n", drvdata->cpu);
}

static void etm4_disable_sysfs_smp_call(void *info)
{
	struct etmv4_drvdata *drvdata = info;

	etm4_disable_hw(drvdata);

	coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);
}

static int etm4_disable_perf(struct coresight_device *csdev,
			     struct perf_event *event)
{
	u32 control;
	struct etm_filters *filters = event->hw.addr_filters;
	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
	struct perf_event_attr *attr = &event->attr;

	if (WARN_ON_ONCE(drvdata->cpu != smp_processor_id()))
		return -EINVAL;

	etm4_disable_hw(drvdata);
	/*
	 * The config_id occupies bits 63:32 of the config2 perf event attr
	 * field. If this is non-zero then we will have enabled a config.
	 */
	if (attr->config2 & GENMASK_ULL(63, 32))
		cscfg_csdev_disable_active_config(csdev);

	/*
	 * Check if the start/stop logic was active when the unit was stopped.
	 * That way we can re-enable the start/stop logic when the process is
	 * scheduled again.  Configuration of the start/stop logic happens in
	 * function etm4_set_event_filters().
	 */
	control = etm4x_relaxed_read32(&csdev->access, TRCVICTLR);
	/* TRCVICTLR::SSSTATUS, bit[9] */
	filters->ssstatus = (control & BIT(9));

	coresight_set_mode(drvdata->csdev, CS_MODE_DISABLED);

	/*
	 * perf will release trace ids when _free_aux() is
	 * called at the end of the session.
	 */

	return 0;
}

static void etm4_disable_sysfs(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.
	 */
	cpus_read_lock();
	raw_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_sysfs_smp_call,
				 drvdata, 1);

	raw_spin_unlock(&drvdata->spinlock);

	cscfg_csdev_disable_active_config(csdev);

	cpus_read_unlock();

	/*
	 * we only release trace IDs when resetting sysfs.
	 * This permits sysfs users to read the trace ID after the trace
	 * session has completed. This maintains operational behaviour with
	 * prior trace id allocation method
	 */

	dev_dbg(&csdev->dev, "ETM tracing disabled\n");
}

static void etm4_disable(struct coresight_device *csdev,
			 struct perf_event *event)
{
	enum cs_mode mode;

	/*
	 * 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 = coresight_get_mode(csdev);

	switch (mode) {
	case CS_MODE_DISABLED:
		break;
	case CS_MODE_SYSFS:
		etm4_disable_sysfs(csdev);
		break;
	case CS_MODE_PERF:
		etm4_disable_perf(csdev, event);
		break;
	}
}

static int etm4_resume_perf(struct coresight_device *csdev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
	struct csdev_access *csa = &csdev->access;

	if (coresight_get_mode(csdev) != CS_MODE_PERF)
		return -EINVAL;

	etm4_cs_unlock(drvdata, csa);
	etm4_enable_trace_unit(drvdata);
	etm4_cs_lock(drvdata, csa);

	drvdata->paused = false;
	return 0;
}

static void etm4_pause_perf(struct coresight_device *csdev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
	struct csdev_access *csa = &csdev->access;

	if (coresight_get_mode(csdev) != CS_MODE_PERF)
		return;

	etm4_cs_unlock(drvdata, csa);
	etm4_disable_trace_unit(drvdata);
	etm4_cs_lock(drvdata, csa);

	drvdata->paused = true;
}

static const struct coresight_ops_source etm4_source_ops = {
	.cpu_id		= etm4_cpu_id,
	.enable		= etm4_enable,
	.disable	= etm4_disable,
	.resume_perf	= etm4_resume_perf,
	.pause_perf	= etm4_pause_perf,
};

static const struct coresight_ops etm4_cs_ops = {
	.trace_id	= coresight_etm_get_trace_id,
	.source_ops	= &etm4_source_ops,
};

static bool cpu_supports_sysreg_trace(void)
{
	u64 dfr0 = read_sysreg_s(SYS_ID_AA64DFR0_EL1);

	return ((dfr0 >> ID_AA64DFR0_EL1_TraceVer_SHIFT) & 0xfUL) > 0;
}

static bool etm4_init_sysreg_access(struct etmv4_drvdata *drvdata,
				    struct csdev_access *csa)
{
	u32 devarch;

	if (!cpu_supports_sysreg_trace())
		return false;

	/*
	 * ETMs implementing sysreg access must implement TRCDEVARCH.
	 */
	devarch = read_etm4x_sysreg_const_offset(TRCDEVARCH);
	switch (devarch & ETM_DEVARCH_ID_MASK) {
	case ETM_DEVARCH_ETMv4x_ARCH:
		*csa = (struct csdev_access) {
			.io_mem	= false,
			.read	= etm4x_sysreg_read,
			.write	= etm4x_sysreg_write,
		};
		break;
	case ETM_DEVARCH_ETE_ARCH:
		*csa = (struct csdev_access) {
			.io_mem	= false,
			.read	= ete_sysreg_read,
			.write	= ete_sysreg_write,
		};
		break;
	default:
		return false;
	}

	drvdata->arch = etm_devarch_to_arch(devarch);
	return true;
}

static bool is_devtype_cpu_trace(void __iomem *base)
{
	u32 devtype = readl(base + TRCDEVTYPE);

	return (devtype == CS_DEVTYPE_PE_TRACE);
}

static bool etm4_init_iomem_access(struct etmv4_drvdata *drvdata,
				   struct csdev_access *csa)
{
	u32 devarch = readl_relaxed(drvdata->base + TRCDEVARCH);

	if (!is_coresight_device(drvdata->base) || !is_devtype_cpu_trace(drvdata->base))
		return false;

	/*
	 * All ETMs must implement TRCDEVARCH to indicate that
	 * the component is an ETMv4. Even though TRCIDR1 also
	 * contains the information, it is part of the "Trace"
	 * register and must be accessed with the OSLK cleared,
	 * with MMIO. But we cannot touch the OSLK until we are
	 * sure this is an ETM. So rely only on the TRCDEVARCH.
	 */
	if ((devarch & ETM_DEVARCH_ID_MASK) != ETM_DEVARCH_ETMv4x_ARCH) {
		pr_warn_once("TRCDEVARCH doesn't match ETMv4 architecture\n");
		return false;
	}

	drvdata->arch = etm_devarch_to_arch(devarch);
	*csa = CSDEV_ACCESS_IOMEM(drvdata->base);
	return true;
}

static bool etm4_init_csdev_access(struct etmv4_drvdata *drvdata,
				   struct csdev_access *csa)
{
	/*
	 * Always choose the memory mapped io, if there is
	 * a memory map to prevent sysreg access on broken
	 * systems.
	 */
	if (drvdata->base)
		return etm4_init_iomem_access(drvdata, csa);

	if (etm4_init_sysreg_access(drvdata, csa))
		return true;

	return false;
}

static void cpu_detect_trace_filtering(struct etmv4_drvdata *drvdata)
{
	u64 dfr0 = read_sysreg(id_aa64dfr0_el1);
	u64 trfcr;

	drvdata->trfcr = 0;
	if (!cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_TraceFilt_SHIFT))
		return;

	/*
	 * If the CPU supports v8.4 SelfHosted Tracing, enable
	 * tracing at the kernel EL and EL0, forcing to use the
	 * virtual time as the timestamp.
	 */
	trfcr = (FIELD_PREP(TRFCR_EL1_TS_MASK, TRFCR_EL1_TS_VIRTUAL) |
		 TRFCR_EL1_ExTRE |
		 TRFCR_EL1_E0TRE);

	/* If we are running at EL2, allow tracing the CONTEXTIDR_EL2. */
	if (is_kernel_in_hyp_mode())
		trfcr |= TRFCR_EL2_CX;

	drvdata->trfcr = trfcr;
}

/*
 * The following errata on applicable cpu ranges, affect the CCITMIN filed
 * in TCRIDR3 register. Software read for the field returns 0x100 limiting
 * the cycle threshold granularity, whereas the right value should have
 * been 0x4, which is well supported in the hardware.
 */
static struct midr_range etm_wrong_ccitmin_cpus[] = {
	/* Erratum #1490853 - Cortex-A76 */
	MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 4, 0),
	/* Erratum #1490853 - Neoverse-N1 */
	MIDR_RANGE(MIDR_NEOVERSE_N1, 0, 0, 4, 0),
	/* Erratum #1491015 - Cortex-A77 */
	MIDR_RANGE(MIDR_CORTEX_A77, 0, 0, 1, 0),
	/* Erratum #1502854 - Cortex-X1 */
	MIDR_REV(MIDR_CORTEX_X1, 0, 0),
	/* Erratum #1619801 - Neoverse-V1 */
	MIDR_REV(MIDR_NEOVERSE_V1, 0, 0),
	{},
};

static void etm4_fixup_wrong_ccitmin(struct etmv4_drvdata *drvdata)
{
	/*
	 * Erratum affected cpus will read 256 as the minimum
	 * instruction trace cycle counting threshold whereas
	 * the correct value should be 4 instead. Override the
	 * recorded value for 'drvdata->ccitmin' to workaround
	 * this problem.
	 */
	if (is_midr_in_range_list(etm_wrong_ccitmin_cpus)) {
		if (drvdata->ccitmin == 256)
			drvdata->ccitmin = 4;
	}
}

static void etm4_init_arch_data(void *info)
{
	u32 etmidr0;
	u32 etmidr2;
	u32 etmidr3;
	u32 etmidr4;
	u32 etmidr5;
	struct etm4_init_arg *init_arg = info;
	struct etmv4_drvdata *drvdata;
	struct csdev_access *csa;
	struct device *dev = init_arg->dev;
	int i;

	drvdata = dev_get_drvdata(init_arg->dev);
	csa = init_arg->csa;

	/*
	 * If we are unable to detect the access mechanism,
	 * or unable to detect the trace unit type, fail
	 * early.
	 */
	if (!etm4_init_csdev_access(drvdata, csa))
		return;

	if (!csa->io_mem ||
	    fwnode_property_present(dev_fwnode(dev), "qcom,skip-power-up"))
		drvdata->skip_power_up = true;

	/* Detect the support for OS Lock before we actually use it */
	etm_detect_os_lock(drvdata, csa);

	/* Make sure all registers are accessible */
	etm4_os_unlock_csa(drvdata, csa);
	etm4_cs_unlock(drvdata, csa);

	etm4_check_arch_features(drvdata, csa);

	/* find all capabilities of the tracing unit */
	etmidr0 = etm4x_relaxed_read32(csa, TRCIDR0);

	/* INSTP0, bits[2:1] P0 tracing support field */
	drvdata->instrp0 = !!(FIELD_GET(TRCIDR0_INSTP0_MASK, etmidr0) == 0b11);
	/* TRCBB, bit[5] Branch broadcast tracing support bit */
	drvdata->trcbb = !!(etmidr0 & TRCIDR0_TRCBB);
	/* TRCCOND, bit[6] Conditional instruction tracing support bit */
	drvdata->trccond = !!(etmidr0 & TRCIDR0_TRCCOND);
	/* TRCCCI, bit[7] Cycle counting instruction bit */
	drvdata->trccci = !!(etmidr0 & TRCIDR0_TRCCCI);
	/* RETSTACK, bit[9] Return stack bit */
	drvdata->retstack = !!(etmidr0 & TRCIDR0_RETSTACK);
	/* NUMEVENT, bits[11:10] Number of events field */
	drvdata->nr_event = FIELD_GET(TRCIDR0_NUMEVENT_MASK, etmidr0);
	/* QSUPP, bits[16:15] Q element support field */
	drvdata->q_support = FIELD_GET(TRCIDR0_QSUPP_MASK, etmidr0);
	if (drvdata->q_support)
		drvdata->q_filt = !!(etmidr0 & TRCIDR0_QFILT);
	/* TSSIZE, bits[28:24] Global timestamp size field */
	drvdata->ts_size = FIELD_GET(TRCIDR0_TSSIZE_MASK, etmidr0);

	/* maximum size of resources */
	etmidr2 = etm4x_relaxed_read32(csa, TRCIDR2);
	/* CIDSIZE, bits[9:5] Indicates the Context ID size */
	drvdata->ctxid_size = FIELD_GET(TRCIDR2_CIDSIZE_MASK, etmidr2);
	/* VMIDSIZE, bits[14:10] Indicates the VMID size */
	drvdata->vmid_size = FIELD_GET(TRCIDR2_VMIDSIZE_MASK, etmidr2);
	/* CCSIZE, bits[28:25] size of the cycle counter in bits minus 12 */
	drvdata->ccsize = FIELD_GET(TRCIDR2_CCSIZE_MASK, etmidr2);

	etmidr3 = etm4x_relaxed_read32(csa, TRCIDR3);
	/* CCITMIN, bits[11:0] minimum threshold value that can be programmed */
	drvdata->ccitmin = FIELD_GET(TRCIDR3_CCITMIN_MASK, etmidr3);
	etm4_fixup_wrong_ccitmin(drvdata);

	/* EXLEVEL_S, bits[19:16] Secure state instruction tracing */
	drvdata->s_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_S_MASK, etmidr3);
	drvdata->config.s_ex_level = drvdata->s_ex_level;
	/* EXLEVEL_NS, bits[23:20] Non-secure state instruction tracing */
	drvdata->ns_ex_level = FIELD_GET(TRCIDR3_EXLEVEL_NS_MASK, etmidr3);
	/*
	 * TRCERR, bit[24] whether a trace unit can trace a
	 * system error exception.
	 */
	drvdata->trc_error = !!(etmidr3 & TRCIDR3_TRCERR);
	/* SYNCPR, bit[25] implementation has a fixed synchronization period? */
	drvdata->syncpr = !!(etmidr3 & TRCIDR3_SYNCPR);
	/* STALLCTL, bit[26] is stall control implemented? */
	drvdata->stallctl = !!(etmidr3 & TRCIDR3_STALLCTL);
	/* SYSSTALL, bit[27] implementation can support stall control? */
	drvdata->sysstall = !!(etmidr3 & TRCIDR3_SYSSTALL);
	/*
	 * NUMPROC - the number of PEs available for tracing, 5bits
	 *         = TRCIDR3.bits[13:12]bits[30:28]
	 *  bits[4:3] = TRCIDR3.bits[13:12] (since etm-v4.2, otherwise RES0)
	 *  bits[3:0] = TRCIDR3.bits[30:28]
	 */
	drvdata->nr_pe =  (FIELD_GET(TRCIDR3_NUMPROC_HI_MASK, etmidr3) << 3) |
			   FIELD_GET(TRCIDR3_NUMPROC_LO_MASK, etmidr3);
	/* NOOVERFLOW, bit[31] is trace overflow prevention supported */
	drvdata->nooverflow = !!(etmidr3 & TRCIDR3_NOOVERFLOW);

	/* number of resources trace unit supports */
	etmidr4 = etm4x_relaxed_read32(csa, TRCIDR4);
	/* NUMACPAIRS, bits[0:3] number of addr comparator pairs for tracing */
	drvdata->nr_addr_cmp = FIELD_GET(TRCIDR4_NUMACPAIRS_MASK, etmidr4);
	/* NUMPC, bits[15:12] number of PE comparator inputs for tracing */
	drvdata->nr_pe_cmp = FIELD_GET(TRCIDR4_NUMPC_MASK, etmidr4);
	/*
	 * NUMRSPAIR, bits[19:16]
	 * The number of resource pairs conveyed by the HW starts at 0, i.e a
	 * value of 0x0 indicate 1 resource pair, 0x1 indicate two and so on.
	 * As such add 1 to the value of NUMRSPAIR for a better representation.
	 *
	 * For ETM v4.3 and later, 0x0 means 0, and no pairs are available -
	 * the default TRUE and FALSE resource selectors are omitted.
	 * Otherwise for values 0x1 and above the number is N + 1 as per v4.2.
	 */
	drvdata->nr_resource = FIELD_GET(TRCIDR4_NUMRSPAIR_MASK, etmidr4);
	if ((drvdata->arch < ETM_ARCH_V4_3) || (drvdata->nr_resource > 0))
		drvdata->nr_resource += 1;
	/*
	 * NUMSSCC, bits[23:20] the number of single-shot
	 * comparator control for tracing. Read any status regs as these
	 * also contain RO capability data.
	 */
	drvdata->nr_ss_cmp = FIELD_GET(TRCIDR4_NUMSSCC_MASK, etmidr4);
	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
		drvdata->config.ss_status[i] =
			etm4x_relaxed_read32(csa, TRCSSCSRn(i));
	}
	/* NUMCIDC, bits[27:24] number of Context ID comparators for tracing */
	drvdata->numcidc = FIELD_GET(TRCIDR4_NUMCIDC_MASK, etmidr4);
	/* NUMVMIDC, bits[31:28] number of VMID comparators for tracing */
	drvdata->numvmidc = FIELD_GET(TRCIDR4_NUMVMIDC_MASK, etmidr4);

	etmidr5 = etm4x_relaxed_read32(csa, TRCIDR5);
	/* NUMEXTIN, bits[8:0] number of external inputs implemented */
	drvdata->nr_ext_inp = FIELD_GET(TRCIDR5_NUMEXTIN_MASK, etmidr5);
	drvdata->numextinsel = FIELD_GET(TRCIDR5_NUMEXTINSEL_MASK, etmidr5);
	/* TRACEIDSIZE, bits[21:16] indicates the trace ID width */
	drvdata->trcid_size = FIELD_GET(TRCIDR5_TRACEIDSIZE_MASK, etmidr5);
	/* ATBTRIG, bit[22] implementation can support ATB triggers? */
	drvdata->atbtrig = !!(etmidr5 & TRCIDR5_ATBTRIG);
	/*
	 * LPOVERRIDE, bit[23] implementation supports
	 * low-power state override
	 */
	drvdata->lpoverride = (etmidr5 & TRCIDR5_LPOVERRIDE) && (!drvdata->skip_power_up);
	/* NUMSEQSTATE, bits[27:25] number of sequencer states implemented */
	drvdata->nrseqstate = FIELD_GET(TRCIDR5_NUMSEQSTATE_MASK, etmidr5);
	/* NUMCNTR, bits[30:28] number of counters available for tracing */
	drvdata->nr_cntr = FIELD_GET(TRCIDR5_NUMCNTR_MASK, etmidr5);

	coresight_clear_self_claim_tag_unlocked(csa);
	etm4_cs_lock(drvdata, csa);
	cpu_detect_trace_filtering(drvdata);
}

static u32 etm4_get_victlr_access_type(struct etmv4_config *config)
{
	return etm4_get_access_type(config) << __bf_shf(TRCVICTLR_EXLEVEL_MASK);
}

/* Set ELx trace filter access in the TRCVICTLR register */
static void etm4_set_victlr_access(struct etmv4_config *config)
{
	config->vinst_ctrl &= ~TRCVICTLR_EXLEVEL_MASK;
	config->vinst_ctrl |= etm4_get_victlr_access_type(config);
}

static void etm4_set_default_config(struct etmv4_config *config)
{
	/* disable all events tracing */
	config->eventctrl0 = 0x0;
	config->eventctrl1 = 0x0;

	/* disable stalling */
	config->stall_ctrl = 0x0;

	/* enable trace synchronization every 4096 bytes, if available */
	config->syncfreq = 0xC;

	/* disable timestamp event */
	config->ts_ctrl = 0x0;

	/* TRCVICTLR::EVENT = 0x01, select the always on logic */
	config->vinst_ctrl = FIELD_PREP(TRCVICTLR_EVENT_MASK, 0x01);

	/* TRCVICTLR::EXLEVEL_NS:EXLEVELS: Set kernel / user filtering */
	etm4_set_victlr_access(config);
}

static u64 etm4_get_ns_access_type(struct etmv4_config *config)
{
	u64 access_type = 0;

	/*
	 * EXLEVEL_NS, for NonSecure Exception levels.
	 * The mask here is a generic value and must be
	 * shifted to the corresponding field for the registers
	 */
	if (!is_kernel_in_hyp_mode()) {
		/* Stay away from hypervisor mode for non-VHE */
		access_type =  ETM_EXLEVEL_NS_HYP;
		if (config->mode & ETM_MODE_EXCL_KERN)
			access_type |= ETM_EXLEVEL_NS_OS;
	} else if (config->mode & ETM_MODE_EXCL_KERN) {
		access_type = ETM_EXLEVEL_NS_HYP;
	}

	if (config->mode & ETM_MODE_EXCL_USER)
		access_type |= ETM_EXLEVEL_NS_APP;

	return access_type;
}

/*
 * Construct the exception level masks for a given config.
 * This must be shifted to the corresponding register field
 * for usage.
 */
static u64 etm4_get_access_type(struct etmv4_config *config)
{
	/* All Secure exception levels are excluded from the trace */
	return etm4_get_ns_access_type(config) | (u64)config->s_ex_level;
}

static u64 etm4_get_comparator_access_type(struct etmv4_config *config)
{
	return etm4_get_access_type(config) << TRCACATR_EXLEVEL_SHIFT;
}

static void etm4_set_comparator_filter(struct etmv4_config *config,
				       u64 start, u64 stop, int comparator)
{
	u64 access_type = etm4_get_comparator_access_type(config);

	/* First half of default address comparator */
	config->addr_val[comparator] = start;
	config->addr_acc[comparator] = access_type;
	config->addr_type[comparator] = ETM_ADDR_TYPE_RANGE;

	/* Second half of default address comparator */
	config->addr_val[comparator + 1] = stop;
	config->addr_acc[comparator + 1] = access_type;
	config->addr_type[comparator + 1] = ETM_ADDR_TYPE_RANGE;

	/*
	 * Configure the ViewInst function to include this address range
	 * comparator.
	 *
	 * @comparator is divided by two since it is the index in the
	 * etmv4_config::addr_val array but register TRCVIIECTLR deals with
	 * address range comparator _pairs_.
	 *
	 * Therefore:
	 *	index 0 -> compatator pair 0
	 *	index 2 -> comparator pair 1
	 *	index 4 -> comparator pair 2
	 *	...
	 *	index 14 -> comparator pair 7
	 */
	config->viiectlr |= BIT(comparator / 2);
}

static void etm4_set_start_stop_filter(struct etmv4_config *config,
				       u64 address, int comparator,
				       enum etm_addr_type type)
{
	int shift;
	u64 access_type = etm4_get_comparator_access_type(config);

	/* Configure the comparator */
	config->addr_val[comparator] = address;
	config->addr_acc[comparator] = access_type;
	config->addr_type[comparator] = type;

	/*
	 * Configure ViewInst Start-Stop control register.
	 * Addresses configured to start tracing go from bit 0 to n-1,
	 * while those configured to stop tracing from 16 to 16 + n-1.
	 */
	shift = (type == ETM_ADDR_TYPE_START ? 0 : 16);
	config->vissctlr |= BIT(shift + comparator);
}

static void etm4_set_default_filter(struct etmv4_config *config)
{
	/* Trace everything 'default' filter achieved by no filtering */
	config->viiectlr = 0x0;

	/*
	 * TRCVICTLR::SSSTATUS == 1, the start-stop logic is
	 * in the started state
	 */
	config->vinst_ctrl |= TRCVICTLR_SSSTATUS;
	config->mode |= ETM_MODE_VIEWINST_STARTSTOP;

	/* No start-stop filtering for ViewInst */
	config->vissctlr = 0x0;
}

static void etm4_set_default(struct etmv4_config *config)
{
	if (WARN_ON_ONCE(!config))
		return;

	/*
	 * Make default initialisation trace everything
	 *
	 * This is done by a minimum default config sufficient to enable
	 * full instruction trace - with a default filter for trace all
	 * achieved by having no filtering.
	 */
	etm4_set_default_config(config);
	etm4_set_default_filter(config);
}

static int etm4_get_next_comparator(struct etmv4_drvdata *drvdata, u32 type)
{
	int nr_comparator, index = 0;
	struct etmv4_config *config = &drvdata->config;

	/*
	 * nr_addr_cmp holds the number of comparator _pair_, so time 2
	 * for the total number of comparators.
	 */
	nr_comparator = drvdata->nr_addr_cmp * 2;

	/* Go through the tally of comparators looking for a free one. */
	while (index < nr_comparator) {
		switch (type) {
		case ETM_ADDR_TYPE_RANGE:
			if (config->addr_type[index] == ETM_ADDR_TYPE_NONE &&
			    config->addr_type[index + 1] == ETM_ADDR_TYPE_NONE)
				return index;

			/* Address range comparators go in pairs */
			index += 2;
			break;
		case ETM_ADDR_TYPE_START:
		case ETM_ADDR_TYPE_STOP:
			if (config->addr_type[index] == ETM_ADDR_TYPE_NONE)
				return index;

			/* Start/stop address can have odd indexes */
			index += 1;
			break;
		default:
			return -EINVAL;
		}
	}

	/* If we are here all the comparators have been used. */
	return -ENOSPC;
}

static int etm4_set_event_filters(struct etmv4_drvdata *drvdata,
				  struct perf_event *event)
{
	int i, comparator, ret = 0;
	u64 address;
	struct etmv4_config *config = &drvdata->config;
	struct etm_filters *filters = event->hw.addr_filters;

	if (!filters)
		goto default_filter;

	/* Sync events with what Perf got */
	perf_event_addr_filters_sync(event);

	/*
	 * If there are no filters to deal with simply go ahead with
	 * the default filter, i.e the entire address range.
	 */
	if (!filters->nr_filters)
		goto default_filter;

	for (i = 0; i < filters->nr_filters; i++) {
		struct etm_filter *filter = &filters->etm_filter[i];
		enum etm_addr_type type = filter->type;

		/* See if a comparator is free. */
		comparator = etm4_get_next_comparator(drvdata, type);
		if (comparator < 0) {
			ret = comparator;
			goto out;
		}

		switch (type) {
		case ETM_ADDR_TYPE_RANGE:
			etm4_set_comparator_filter(config,
						   filter->start_addr,
						   filter->stop_addr,
						   comparator);
			/*
			 * TRCVICTLR::SSSTATUS == 1, the start-stop logic is
			 * in the started state
			 */
			config->vinst_ctrl |= TRCVICTLR_SSSTATUS;

			/* No start-stop filtering for ViewInst */
			config->vissctlr = 0x0;
			break;
		case ETM_ADDR_TYPE_START:
		case ETM_ADDR_TYPE_STOP:
			/* Get the right start or stop address */
			address = (type == ETM_ADDR_TYPE_START ?
				   filter->start_addr :
				   filter->stop_addr);

			/* Configure comparator */
			etm4_set_start_stop_filter(config, address,
						   comparator, type);

			/*
			 * If filters::ssstatus == 1, trace acquisition was
			 * started but the process was yanked away before the
			 * stop address was hit.  As such the start/stop
			 * logic needs to be re-started so that tracing can
			 * resume where it left.
			 *
			 * The start/stop logic status when a process is
			 * scheduled out is checked in function
			 * etm4_disable_perf().
			 */
			if (filters->ssstatus)
				config->vinst_ctrl |= TRCVICTLR_SSSTATUS;

			/* No include/exclude filtering for ViewInst */
			config->viiectlr = 0x0;
			break;
		default:
			ret = -EINVAL;
			goto out;
		}
	}

	goto out;


default_filter:
	etm4_set_default_filter(config);

out:
	return ret;
}

void etm4_config_trace_mode(struct etmv4_config *config)
{
	u32 mode;

	mode = config->mode;
	mode &= (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER);

	/* excluding kernel AND user space doesn't make sense */
	WARN_ON_ONCE(mode == (ETM_MODE_EXCL_KERN | ETM_MODE_EXCL_USER));

	/* nothing to do if neither flags are set */
	if (!(mode & ETM_MODE_EXCL_KERN) && !(mode & ETM_MODE_EXCL_USER))
		return;

	etm4_set_victlr_access(config);
}

static int etm4_online_cpu(unsigned int cpu)
{
	if (!etmdrvdata[cpu])
		return etm4_probe_cpu(cpu);

	if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
		coresight_enable_sysfs(etmdrvdata[cpu]->csdev);
	return 0;
}

static int etm4_starting_cpu(unsigned int cpu)
{
	if (!etmdrvdata[cpu])
		return 0;

	raw_spin_lock(&etmdrvdata[cpu]->spinlock);
	if (!etmdrvdata[cpu]->os_unlock)
		etm4_os_unlock(etmdrvdata[cpu]);

	if (coresight_get_mode(etmdrvdata[cpu]->csdev))
		etm4_enable_hw(etmdrvdata[cpu]);
	raw_spin_unlock(&etmdrvdata[cpu]->spinlock);
	return 0;
}

static int etm4_dying_cpu(unsigned int cpu)
{
	if (!etmdrvdata[cpu])
		return 0;

	raw_spin_lock(&etmdrvdata[cpu]->spinlock);
	if (coresight_get_mode(etmdrvdata[cpu]->csdev))
		etm4_disable_hw(etmdrvdata[cpu]);
	raw_spin_unlock(&etmdrvdata[cpu]->spinlock);
	return 0;
}

static int __etm4_cpu_save(struct etmv4_drvdata *drvdata)
{
	int i, ret = 0;
	struct etmv4_save_state *state;
	struct coresight_device *csdev = drvdata->csdev;
	struct csdev_access *csa;
	struct device *etm_dev;

	if (WARN_ON(!csdev))
		return -ENODEV;

	etm_dev = &csdev->dev;
	csa = &csdev->access;

	/*
	 * As recommended by 3.4.1 ("The procedure when powering down the PE")
	 * of ARM IHI 0064D
	 */
	dsb(sy);
	isb();

	etm4_cs_unlock(drvdata, csa);
	/* Lock the OS lock to disable trace and external debugger access */
	etm4_os_lock(drvdata);

	/* wait for TRCSTATR.PMSTABLE to go up */
	if (etm4x_wait_status(csa, TRCSTATR_PMSTABLE_BIT, 1)) {
		dev_err(etm_dev,
			"timeout while waiting for PM Stable Status\n");
		etm4_os_unlock(drvdata);
		ret = -EBUSY;
		goto out;
	}

	if (!drvdata->paused)
		etm4_disable_trace_unit(drvdata);

	state = drvdata->save_state;

	if (drvdata->nr_pe)
		state->trcprocselr = etm4x_read32(csa, TRCPROCSELR);
	state->trcconfigr = etm4x_read32(csa, TRCCONFIGR);
	state->trcauxctlr = etm4x_read32(csa, TRCAUXCTLR);
	state->trceventctl0r = etm4x_read32(csa, TRCEVENTCTL0R);
	state->trceventctl1r = etm4x_read32(csa, TRCEVENTCTL1R);
	if (drvdata->stallctl)
		state->trcstallctlr = etm4x_read32(csa, TRCSTALLCTLR);
	state->trctsctlr = etm4x_read32(csa, TRCTSCTLR);
	state->trcsyncpr = etm4x_read32(csa, TRCSYNCPR);
	state->trcccctlr = etm4x_read32(csa, TRCCCCTLR);
	state->trcbbctlr = etm4x_read32(csa, TRCBBCTLR);
	state->trctraceidr = etm4x_read32(csa, TRCTRACEIDR);
	if (drvdata->q_filt)
		state->trcqctlr = etm4x_read32(csa, TRCQCTLR);

	state->trcvictlr = etm4x_read32(csa, TRCVICTLR);
	state->trcviiectlr = etm4x_read32(csa, TRCVIIECTLR);
	state->trcvissctlr = etm4x_read32(csa, TRCVISSCTLR);
	if (drvdata->nr_pe_cmp)
		state->trcvipcssctlr = etm4x_read32(csa, TRCVIPCSSCTLR);

	for (i = 0; i < drvdata->nrseqstate - 1; i++)
		state->trcseqevr[i] = etm4x_read32(csa, TRCSEQEVRn(i));

	if (drvdata->nrseqstate) {
		state->trcseqrstevr = etm4x_read32(csa, TRCSEQRSTEVR);
		state->trcseqstr = etm4x_read32(csa, TRCSEQSTR);
	}

	if (drvdata->numextinsel)
		state->trcextinselr = etm4x_read32(csa, TRCEXTINSELR);

	for (i = 0; i < drvdata->nr_cntr; i++) {
		state->trccntrldvr[i] = etm4x_read32(csa, TRCCNTRLDVRn(i));
		state->trccntctlr[i] = etm4x_read32(csa, TRCCNTCTLRn(i));
		state->trccntvr[i] = etm4x_read32(csa, TRCCNTVRn(i));
	}

	/* Resource selector pair 0 is reserved */
	for (i = 2; i < drvdata->nr_resource * 2; i++)
		state->trcrsctlr[i] = etm4x_read32(csa, TRCRSCTLRn(i));

	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
		state->trcssccr[i] = etm4x_read32(csa, TRCSSCCRn(i));
		state->trcsscsr[i] = etm4x_read32(csa, TRCSSCSRn(i));
		if (etm4x_sspcicrn_present(drvdata, i))
			state->trcsspcicr[i] = etm4x_read32(csa, TRCSSPCICRn(i));
	}

	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
		state->trcacvr[i] = etm4x_read64(csa, TRCACVRn(i));
		state->trcacatr[i] = etm4x_read64(csa, TRCACATRn(i));
	}

	/*
	 * Data trace stream is architecturally prohibited for A profile cores
	 * so we don't save (or later restore) trcdvcvr and trcdvcmr - As per
	 * section 1.3.4 ("Possible functional configurations of an ETMv4 trace
	 * unit") of ARM IHI 0064D.
	 */

	for (i = 0; i < drvdata->numcidc; i++)
		state->trccidcvr[i] = etm4x_read64(csa, TRCCIDCVRn(i));

	for (i = 0; i < drvdata->numvmidc; i++)
		state->trcvmidcvr[i] = etm4x_read64(csa, TRCVMIDCVRn(i));

	state->trccidcctlr0 = etm4x_read32(csa, TRCCIDCCTLR0);
	if (drvdata->numcidc > 4)
		state->trccidcctlr1 = etm4x_read32(csa, TRCCIDCCTLR1);

	state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR0);
	if (drvdata->numvmidc > 4)
		state->trcvmidcctlr0 = etm4x_read32(csa, TRCVMIDCCTLR1);

	state->trcclaimset = etm4x_read32(csa, TRCCLAIMCLR);

	if (!drvdata->skip_power_up)
		state->trcpdcr = etm4x_read32(csa, TRCPDCR);

	/* wait for TRCSTATR.IDLE to go up */
	if (etm4x_wait_status(csa, TRCSTATR_IDLE_BIT, 1)) {
		dev_err(etm_dev,
			"timeout while waiting for Idle Trace Status\n");
		etm4_os_unlock(drvdata);
		ret = -EBUSY;
		goto out;
	}

	/*
	 * Power can be removed from the trace unit now. We do this to
	 * potentially save power on systems that respect the TRCPDCR_PU
	 * despite requesting software to save/restore state.
	 */
	if (!drvdata->skip_power_up)
		etm4x_relaxed_write32(csa, (state->trcpdcr & ~TRCPDCR_PU),
				      TRCPDCR);
out:
	etm4_cs_lock(drvdata, csa);
	return ret;
}

static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
{
	int ret = 0;

	if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED)
		return 0;

	/*
	 * Save and restore the ETM Trace registers only if
	 * the ETM is active.
	 */
	if (coresight_get_mode(drvdata->csdev))
		ret = __etm4_cpu_save(drvdata);
	return ret;
}

static void __etm4_cpu_restore(struct etmv4_drvdata *drvdata)
{
	int i;
	struct etmv4_save_state *state = drvdata->save_state;
	struct csdev_access *csa = &drvdata->csdev->access;

	if (WARN_ON(!drvdata->csdev))
		return;

	etm4_cs_unlock(drvdata, csa);
	etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET);

	if (drvdata->nr_pe)
		etm4x_relaxed_write32(csa, state->trcprocselr, TRCPROCSELR);
	etm4x_relaxed_write32(csa, state->trcconfigr, TRCCONFIGR);
	etm4x_relaxed_write32(csa, state->trcauxctlr, TRCAUXCTLR);
	etm4x_relaxed_write32(csa, state->trceventctl0r, TRCEVENTCTL0R);
	etm4x_relaxed_write32(csa, state->trceventctl1r, TRCEVENTCTL1R);
	if (drvdata->stallctl)
		etm4x_relaxed_write32(csa, state->trcstallctlr, TRCSTALLCTLR);
	etm4x_relaxed_write32(csa, state->trctsctlr, TRCTSCTLR);
	etm4x_relaxed_write32(csa, state->trcsyncpr, TRCSYNCPR);
	etm4x_relaxed_write32(csa, state->trcccctlr, TRCCCCTLR);
	etm4x_relaxed_write32(csa, state->trcbbctlr, TRCBBCTLR);
	etm4x_relaxed_write32(csa, state->trctraceidr, TRCTRACEIDR);
	if (drvdata->q_filt)
		etm4x_relaxed_write32(csa, state->trcqctlr, TRCQCTLR);

	etm4x_relaxed_write32(csa, state->trcvictlr, TRCVICTLR);
	etm4x_relaxed_write32(csa, state->trcviiectlr, TRCVIIECTLR);
	etm4x_relaxed_write32(csa, state->trcvissctlr, TRCVISSCTLR);
	if (drvdata->nr_pe_cmp)
		etm4x_relaxed_write32(csa, state->trcvipcssctlr, TRCVIPCSSCTLR);

	for (i = 0; i < drvdata->nrseqstate - 1; i++)
		etm4x_relaxed_write32(csa, state->trcseqevr[i], TRCSEQEVRn(i));

	if (drvdata->nrseqstate) {
		etm4x_relaxed_write32(csa, state->trcseqrstevr, TRCSEQRSTEVR);
		etm4x_relaxed_write32(csa, state->trcseqstr, TRCSEQSTR);
	}
	if (drvdata->numextinsel)
		etm4x_relaxed_write32(csa, state->trcextinselr, TRCEXTINSELR);

	for (i = 0; i < drvdata->nr_cntr; i++) {
		etm4x_relaxed_write32(csa, state->trccntrldvr[i], TRCCNTRLDVRn(i));
		etm4x_relaxed_write32(csa, state->trccntctlr[i], TRCCNTCTLRn(i));
		etm4x_relaxed_write32(csa, state->trccntvr[i], TRCCNTVRn(i));
	}

	/* Resource selector pair 0 is reserved */
	for (i = 2; i < drvdata->nr_resource * 2; i++)
		etm4x_relaxed_write32(csa, state->trcrsctlr[i], TRCRSCTLRn(i));

	for (i = 0; i < drvdata->nr_ss_cmp; i++) {
		etm4x_relaxed_write32(csa, state->trcssccr[i], TRCSSCCRn(i));
		etm4x_relaxed_write32(csa, state->trcsscsr[i], TRCSSCSRn(i));
		if (etm4x_sspcicrn_present(drvdata, i))
			etm4x_relaxed_write32(csa, state->trcsspcicr[i], TRCSSPCICRn(i));
	}

	for (i = 0; i < drvdata->nr_addr_cmp * 2; i++) {
		etm4x_relaxed_write64(csa, state->trcacvr[i], TRCACVRn(i));
		etm4x_relaxed_write64(csa, state->trcacatr[i], TRCACATRn(i));
	}

	for (i = 0; i < drvdata->numcidc; i++)
		etm4x_relaxed_write64(csa, state->trccidcvr[i], TRCCIDCVRn(i));

	for (i = 0; i < drvdata->numvmidc; i++)
		etm4x_relaxed_write64(csa, state->trcvmidcvr[i], TRCVMIDCVRn(i));

	etm4x_relaxed_write32(csa, state->trccidcctlr0, TRCCIDCCTLR0);
	if (drvdata->numcidc > 4)
		etm4x_relaxed_write32(csa, state->trccidcctlr1, TRCCIDCCTLR1);

	etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR0);
	if (drvdata->numvmidc > 4)
		etm4x_relaxed_write32(csa, state->trcvmidcctlr0, TRCVMIDCCTLR1);

	etm4x_relaxed_write32(csa, state->trcclaimset, TRCCLAIMSET);

	if (!drvdata->skip_power_up)
		etm4x_relaxed_write32(csa, state->trcpdcr, TRCPDCR);

	/*
	 * As recommended by section 4.3.7 ("Synchronization when using the
	 * memory-mapped interface") of ARM IHI 0064D
	 */
	dsb(sy);
	isb();

	/* Unlock the OS lock to re-enable trace and external debug access */
	etm4_os_unlock(drvdata);

	if (!drvdata->paused)
		etm4_enable_trace_unit(drvdata);

	etm4_cs_lock(drvdata, csa);
}

static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
{
	if (pm_save_enable != PARAM_PM_SAVE_SELF_HOSTED)
		return;

	if (coresight_get_mode(drvdata->csdev))
		__etm4_cpu_restore(drvdata);
}

static int etm4_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
			      void *v)
{
	struct etmv4_drvdata *drvdata;
	unsigned int cpu = smp_processor_id();

	if (!etmdrvdata[cpu])
		return NOTIFY_OK;

	drvdata = etmdrvdata[cpu];

	if (WARN_ON_ONCE(drvdata->cpu != cpu))
		return NOTIFY_BAD;

	switch (cmd) {
	case CPU_PM_ENTER:
		if (etm4_cpu_save(drvdata))
			return NOTIFY_BAD;
		break;
	case CPU_PM_EXIT:
	case CPU_PM_ENTER_FAILED:
		etm4_cpu_restore(drvdata);
		break;
	default:
		return NOTIFY_DONE;
	}

	return NOTIFY_OK;
}

static struct notifier_block etm4_cpu_pm_nb = {
	.notifier_call = etm4_cpu_pm_notify,
};

/* Setup PM. Deals with error conditions and counts */
static int __init etm4_pm_setup(void)
{
	int ret;

	ret = cpu_pm_register_notifier(&etm4_cpu_pm_nb);
	if (ret)
		return ret;

	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,
					"arm/coresight4:starting",
					etm4_starting_cpu, etm4_dying_cpu);

	if (ret)
		goto unregister_notifier;

	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
					"arm/coresight4:online",
					etm4_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);

unregister_notifier:
	cpu_pm_unregister_notifier(&etm4_cpu_pm_nb);
	return ret;
}

static void etm4_pm_clear(void)
{
	cpu_pm_unregister_notifier(&etm4_cpu_pm_nb);
	cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);
	if (hp_online) {
		cpuhp_remove_state_nocalls(hp_online);
		hp_online = 0;
	}
}

static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
{
	int ret;
	struct coresight_platform_data *pdata = NULL;
	struct device *dev = init_arg->dev;
	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
	struct coresight_desc desc = { 0 };
	u8 major, minor;
	char *type_name;

	if (!drvdata)
		return -EINVAL;

	desc.access = *init_arg->csa;

	if (!drvdata->arch)
		return -EINVAL;

	major = ETM_ARCH_MAJOR_VERSION(drvdata->arch);
	minor = ETM_ARCH_MINOR_VERSION(drvdata->arch);

	if (etm4x_is_ete(drvdata)) {
		type_name = "ete";
		/* ETE v1 has major version == 0b101. Adjust this for logging.*/
		major -= 4;
	} else {
		type_name = "etm";
	}

	desc.name = devm_kasprintf(dev, GFP_KERNEL,
				   "%s%d", type_name, drvdata->cpu);
	if (!desc.name)
		return -ENOMEM;

	etm4_set_default(&drvdata->config);

	pdata = coresight_get_platform_data(dev);
	if (IS_ERR(pdata))
		return PTR_ERR(pdata);

	dev->platform_data = pdata;

	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))
		return PTR_ERR(drvdata->csdev);

	ret = etm_perf_symlink(drvdata->csdev, true);
	if (ret) {
		coresight_unregister(drvdata->csdev);
		return ret;
	}

	/* register with config infrastructure & load any current features */
	ret = etm4_cscfg_register(drvdata->csdev);
	if (ret) {
		coresight_unregister(drvdata->csdev);
		return ret;
	}

	etmdrvdata[drvdata->cpu] = drvdata;

	dev_info(&drvdata->csdev->dev, "CPU%d: %s v%d.%d initialized\n",
		 drvdata->cpu, type_name, major, minor);

	if (boot_enable) {
		coresight_enable_sysfs(drvdata->csdev);
		drvdata->boot_enable = true;
	}

	return 0;
}

static int etm4_probe(struct device *dev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
	struct csdev_access access = { 0 };
	struct etm4_init_arg init_arg = { 0 };
	struct etm4_init_arg *delayed;
	int ret;

	if (WARN_ON(!drvdata))
		return -ENOMEM;

	ret = coresight_get_enable_clocks(dev, &drvdata->pclk, &drvdata->atclk);
	if (ret)
		return ret;

	if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE)
		pm_save_enable = coresight_loses_context_with_cpu(dev) ?
			       PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER;

	if (pm_save_enable != PARAM_PM_SAVE_NEVER) {
		drvdata->save_state = devm_kmalloc(dev,
				sizeof(struct etmv4_save_state), GFP_KERNEL);
		if (!drvdata->save_state)
			return -ENOMEM;
	}

	raw_spin_lock_init(&drvdata->spinlock);

	drvdata->cpu = coresight_get_cpu(dev);
	if (drvdata->cpu < 0)
		return drvdata->cpu;

	init_arg.dev = dev;
	init_arg.csa = &access;

	/*
	 * Serialize against CPUHP callbacks to avoid race condition
	 * between the smp call and saving the delayed probe.
	 */
	cpus_read_lock();
	if (smp_call_function_single(drvdata->cpu,
				etm4_init_arch_data,  &init_arg, 1)) {
		/* The CPU was offline, try again once it comes online. */
		delayed = devm_kmalloc(dev, sizeof(*delayed), GFP_KERNEL);
		if (!delayed) {
			cpus_read_unlock();
			return -ENOMEM;
		}

		*delayed = init_arg;

		per_cpu(delayed_probe, drvdata->cpu) = delayed;

		cpus_read_unlock();
		return 0;
	}
	cpus_read_unlock();

	return etm4_add_coresight_dev(&init_arg);
}

static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
{
	struct etmv4_drvdata *drvdata;
	void __iomem *base;
	struct device *dev = &adev->dev;
	struct resource *res = &adev->res;
	int ret;

	/* 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 = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
	if (!drvdata)
		return -ENOMEM;

	drvdata->base = base;
	dev_set_drvdata(dev, drvdata);
	ret = etm4_probe(dev);
	if (!ret)
		pm_runtime_put(&adev->dev);

	return ret;
}

static int etm4_probe_platform_dev(struct platform_device *pdev)
{
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	struct etmv4_drvdata *drvdata;
	int ret;

	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
	if (!drvdata)
		return -ENOMEM;

	if (res) {
		drvdata->base = devm_ioremap_resource(&pdev->dev, res);
		if (IS_ERR(drvdata->base))
			return PTR_ERR(drvdata->base);
	}

	dev_set_drvdata(&pdev->dev, drvdata);
	pm_runtime_get_noresume(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	ret = etm4_probe(&pdev->dev);

	pm_runtime_put(&pdev->dev);
	if (ret)
		pm_runtime_disable(&pdev->dev);

	return ret;
}

static int etm4_probe_cpu(unsigned int cpu)
{
	int ret;
	struct etm4_init_arg init_arg;
	struct csdev_access access = { 0 };
	struct etm4_init_arg *iap = *this_cpu_ptr(&delayed_probe);

	if (!iap)
		return 0;

	init_arg = *iap;
	devm_kfree(init_arg.dev, iap);
	*this_cpu_ptr(&delayed_probe) = NULL;

	ret = pm_runtime_resume_and_get(init_arg.dev);
	if (ret < 0) {
		dev_err(init_arg.dev, "Failed to get PM runtime!\n");
		return 0;
	}

	init_arg.csa = &access;
	etm4_init_arch_data(&init_arg);

	etm4_add_coresight_dev(&init_arg);

	pm_runtime_put(init_arg.dev);
	return 0;
}

static struct amba_cs_uci_id uci_id_etm4[] = {
	{
		/*  ETMv4 UCI data */
		.devarch	= ETM_DEVARCH_ETMv4x_ARCH,
		.devarch_mask	= ETM_DEVARCH_ID_MASK,
		.devtype	= CS_DEVTYPE_PE_TRACE,
	}
};

static void clear_etmdrvdata(void *info)
{
	int cpu = *(int *)info;

	etmdrvdata[cpu] = NULL;
	per_cpu(delayed_probe, cpu) = NULL;
}

static void etm4_remove_dev(struct etmv4_drvdata *drvdata)
{
	bool had_delayed_probe;
	/*
	 * Taking hotplug lock here to avoid racing between etm4_remove_dev()
	 * and CPU hotplug call backs.
	 */
	cpus_read_lock();

	had_delayed_probe = per_cpu(delayed_probe, drvdata->cpu);

	/*
	 * 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))
		clear_etmdrvdata(&drvdata->cpu);

	cpus_read_unlock();

	if (!had_delayed_probe) {
		etm_perf_symlink(drvdata->csdev, false);
		cscfg_unregister_csdev(drvdata->csdev);
		coresight_unregister(drvdata->csdev);
	}
}

static void etm4_remove_amba(struct amba_device *adev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(&adev->dev);

	if (drvdata)
		etm4_remove_dev(drvdata);
}

static void etm4_remove_platform_dev(struct platform_device *pdev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(&pdev->dev);

	if (drvdata)
		etm4_remove_dev(drvdata);
	pm_runtime_disable(&pdev->dev);
}

static const struct amba_id etm4_ids[] = {
	CS_AMBA_ID(0x000bb95d),			/* Cortex-A53 */
	CS_AMBA_ID(0x000bb95e),			/* Cortex-A57 */
	CS_AMBA_ID(0x000bb95a),			/* Cortex-A72 */
	CS_AMBA_ID(0x000bb959),			/* Cortex-A73 */
	CS_AMBA_UCI_ID(0x000bb9da, uci_id_etm4),/* Cortex-A35 */
	CS_AMBA_UCI_ID(0x000bbd05, uci_id_etm4),/* Cortex-A55 */
	CS_AMBA_UCI_ID(0x000bbd0a, uci_id_etm4),/* Cortex-A75 */
	CS_AMBA_UCI_ID(0x000bbd0c, uci_id_etm4),/* Neoverse N1 */
	CS_AMBA_UCI_ID(0x000bbd41, uci_id_etm4),/* Cortex-A78 */
	CS_AMBA_UCI_ID(0x000f0205, uci_id_etm4),/* Qualcomm Kryo */
	CS_AMBA_UCI_ID(0x000f0211, uci_id_etm4),/* Qualcomm Kryo */
	CS_AMBA_UCI_ID(0x000bb802, uci_id_etm4),/* Qualcomm Kryo 385 Cortex-A55 */
	CS_AMBA_UCI_ID(0x000bb803, uci_id_etm4),/* Qualcomm Kryo 385 Cortex-A75 */
	CS_AMBA_UCI_ID(0x000bb805, uci_id_etm4),/* Qualcomm Kryo 4XX Cortex-A55 */
	CS_AMBA_UCI_ID(0x000bb804, uci_id_etm4),/* Qualcomm Kryo 4XX Cortex-A76 */
	CS_AMBA_UCI_ID(0x000bbd0d, uci_id_etm4),/* Qualcomm Kryo 5XX Cortex-A77 */
	CS_AMBA_UCI_ID(0x000cc0af, uci_id_etm4),/* Marvell ThunderX2 */
	CS_AMBA_UCI_ID(0x000b6d01, uci_id_etm4),/* HiSilicon-Hip08 */
	CS_AMBA_UCI_ID(0x000b6d02, uci_id_etm4),/* HiSilicon-Hip09 */
	/*
	 * Match all PIDs with ETM4 DEVARCH. No need for adding any of the new
	 * CPUs to the list here.
	 */
	CS_AMBA_MATCH_ALL_UCI(uci_id_etm4),
	{},
};

MODULE_DEVICE_TABLE(amba, etm4_ids);

static struct amba_driver etm4x_amba_driver = {
	.drv = {
		.name   = "coresight-etm4x",
		.suppress_bind_attrs = true,
	},
	.probe		= etm4_probe_amba,
	.remove         = etm4_remove_amba,
	.id_table	= etm4_ids,
};

#ifdef CONFIG_PM
static int etm4_runtime_suspend(struct device *dev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);

	clk_disable_unprepare(drvdata->atclk);
	clk_disable_unprepare(drvdata->pclk);

	return 0;
}

static int etm4_runtime_resume(struct device *dev)
{
	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
	int ret;

	ret = clk_prepare_enable(drvdata->pclk);
	if (ret)
		return ret;

	ret = clk_prepare_enable(drvdata->atclk);
	if (ret)
		clk_disable_unprepare(drvdata->pclk);

	return ret;
}
#endif

static const struct dev_pm_ops etm4_dev_pm_ops = {
	SET_RUNTIME_PM_OPS(etm4_runtime_suspend, etm4_runtime_resume, NULL)
};

static const struct of_device_id etm4_sysreg_match[] = {
	{ .compatible	= "arm,coresight-etm4x-sysreg" },
	{ .compatible	= "arm,embedded-trace-extension" },
	{}
};

#ifdef CONFIG_ACPI
static const struct acpi_device_id etm4x_acpi_ids[] = {
	{"ARMHC500", 0, 0, 0}, /* ARM CoreSight ETM4x */
	{}
};
MODULE_DEVICE_TABLE(acpi, etm4x_acpi_ids);
#endif

static struct platform_driver etm4_platform_driver = {
	.probe		= etm4_probe_platform_dev,
	.remove		= etm4_remove_platform_dev,
	.driver			= {
		.name			= "coresight-etm4x",
		.of_match_table		= etm4_sysreg_match,
		.acpi_match_table	= ACPI_PTR(etm4x_acpi_ids),
		.suppress_bind_attrs	= true,
		.pm			= &etm4_dev_pm_ops,
	},
};

static int __init etm4x_init(void)
{
	int ret;

	ret = etm4_pm_setup();

	/* etm4_pm_setup() does its own cleanup - exit on error */
	if (ret)
		return ret;

	ret = amba_driver_register(&etm4x_amba_driver);
	if (ret) {
		pr_err("Error registering etm4x AMBA driver\n");
		goto clear_pm;
	}

	ret = platform_driver_register(&etm4_platform_driver);
	if (!ret)
		return 0;

	pr_err("Error registering etm4x platform driver\n");
	amba_driver_unregister(&etm4x_amba_driver);

clear_pm:
	etm4_pm_clear();
	return ret;
}

static void __exit etm4x_exit(void)
{
	amba_driver_unregister(&etm4x_amba_driver);
	platform_driver_unregister(&etm4_platform_driver);
	etm4_pm_clear();
}

module_init(etm4x_init);
module_exit(etm4x_exit);

MODULE_AUTHOR("Pratik Patel <pratikp@codeaurora.org>");
MODULE_AUTHOR("Mathieu Poirier <mathieu.poirier@linaro.org>");
MODULE_DESCRIPTION("Arm CoreSight Program Flow Trace v4.x driver");
MODULE_LICENSE("GPL v2");