Merge branch 'for-4.8/hid-led' into for-linus

[mirror_ubuntu-zesty-kernel.git] / 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/coresight-pmu.h>
#include <linux/pm_wakeup.h>
#include <linux/amba/bus.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/perf_event.h>
#include <linux/pm_runtime.h>
#include <linux/perf_event.h>
#include <asm/sections.h>
#include <asm/local.h>

#include "coresight-etm4x.h"
#include "coresight-etm-perf.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_set_default(struct etmv4_config *config);

static void etm4_os_unlock(struct etmv4_drvdata *drvdata)
{
        /* Writing any value to ETMOSLAR unlocks the trace registers */
        writel_relaxed(0x0, drvdata->base + TRCOSLAR);
        drvdata->os_unlock = true;
        isb();
}

static bool etm4_arch_supported(u8 arch)
{
        switch (arch) {
        case ETM_ARCH_V4:
                break;
        default:
                return false;
        }
        return true;
}

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

        return drvdata->cpu;
}

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 (!local_read(&drvdata->mode))
                return drvdata->trcid;

        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);

        return trace_id;
}

static void etm4_enable_hw(void *info)
{
        int i;
        struct etmv4_drvdata *drvdata = info;
        struct etmv4_config *config = &drvdata->config;

        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(config->pe_sel, drvdata->base + TRCPROCSELR);
        writel_relaxed(config->cfg, drvdata->base + TRCCONFIGR);
        /* nothing specific implemented */
        writel_relaxed(0x0, drvdata->base + TRCAUXCTLR);
        writel_relaxed(config->eventctrl0, drvdata->base + TRCEVENTCTL0R);
        writel_relaxed(config->eventctrl1, drvdata->base + TRCEVENTCTL1R);
        writel_relaxed(config->stall_ctrl, drvdata->base + TRCSTALLCTLR);
        writel_relaxed(config->ts_ctrl, drvdata->base + TRCTSCTLR);
        writel_relaxed(config->syncfreq, drvdata->base + TRCSYNCPR);
        writel_relaxed(config->ccctlr, drvdata->base + TRCCCCTLR);
        writel_relaxed(config->bb_ctrl, drvdata->base + TRCBBCTLR);
        writel_relaxed(drvdata->trcid, drvdata->base + TRCTRACEIDR);
        writel_relaxed(config->vinst_ctrl, drvdata->base + TRCVICTLR);
        writel_relaxed(config->viiectlr, drvdata->base + TRCVIIECTLR);
        writel_relaxed(config->vissctlr,
                       drvdata->base + TRCVISSCTLR);
        writel_relaxed(config->vipcssctlr,
                       drvdata->base + TRCVIPCSSCTLR);
        for (i = 0; i < drvdata->nrseqstate - 1; i++)
                writel_relaxed(config->seq_ctrl[i],
                               drvdata->base + TRCSEQEVRn(i));
        writel_relaxed(config->seq_rst, drvdata->base + TRCSEQRSTEVR);
        writel_relaxed(config->seq_state, drvdata->base + TRCSEQSTR);
        writel_relaxed(config->ext_inp, drvdata->base + TRCEXTINSELR);
        for (i = 0; i < drvdata->nr_cntr; i++) {
                writel_relaxed(config->cntrldvr[i],
                               drvdata->base + TRCCNTRLDVRn(i));
                writel_relaxed(config->cntr_ctrl[i],
                               drvdata->base + TRCCNTCTLRn(i));
                writel_relaxed(config->cntr_val[i],
                               drvdata->base + TRCCNTVRn(i));
        }

        /* Resource selector pair 0 is always implemented and reserved */
        for (i = 0; i < drvdata->nr_resource * 2; i++)
                writel_relaxed(config->res_ctrl[i],
                               drvdata->base + TRCRSCTLRn(i));

        for (i = 0; i < drvdata->nr_ss_cmp; i++) {
                writel_relaxed(config->ss_ctrl[i],
                               drvdata->base + TRCSSCCRn(i));
                writel_relaxed(config->ss_status[i],
                               drvdata->base + TRCSSCSRn(i));
                writel_relaxed(config->ss_pe_cmp[i],
                               drvdata->base + TRCSSPCICRn(i));
        }
        for (i = 0; i < drvdata->nr_addr_cmp; i++) {
                writeq_relaxed(config->addr_val[i],
                               drvdata->base + TRCACVRn(i));
                writeq_relaxed(config->addr_acc[i],
                               drvdata->base + TRCACATRn(i));
        }
        for (i = 0; i < drvdata->numcidc; i++)
                writeq_relaxed(config->ctxid_pid[i],
                               drvdata->base + TRCCIDCVRn(i));
        writel_relaxed(config->ctxid_mask0, drvdata->base + TRCCIDCCTLR0);
        writel_relaxed(config->ctxid_mask1, drvdata->base + TRCCIDCCTLR1);

        for (i = 0; i < drvdata->numvmidc; i++)
                writeq_relaxed(config->vmid_val[i],
                               drvdata->base + TRCVMIDCVRn(i));
        writel_relaxed(config->vmid_mask0, drvdata->base + TRCVMIDCCTLR0);
        writel_relaxed(config->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_parse_event_config(struct etmv4_drvdata *drvdata,
                                   struct perf_event_attr *attr)
{
        struct etmv4_config *config = &drvdata->config;

        if (!attr)
                return -EINVAL;

        /* 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;

        /* Always start from the default config */
        etm4_set_default(config);

        /*
         * By default the tracers are configured to trace the whole address
         * range.  Narrow the field only if requested by user space.
         */
        if (config->mode)
                etm4_config_trace_mode(config);

        /* Go from generic option to ETMv4 specifics */
        if (attr->config & BIT(ETM_OPT_CYCACC))
                config->cfg |= ETMv4_MODE_CYCACC;
        if (attr->config & BIT(ETM_OPT_TS))
                config->cfg |= ETMv4_MODE_TIMESTAMP;

        return 0;
}

static int etm4_enable_perf(struct coresight_device *csdev,
                            struct perf_event_attr *attr)
{
        struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

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

        /* Configure the tracer based on the session's specifics */
        etm4_parse_event_config(drvdata, attr);
        /* And enable it */
        etm4_enable_hw(drvdata);

        return 0;
}

static int etm4_enable_sysfs(struct coresight_device *csdev)
{
        struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
        int ret;

        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->sticky_enable = true;
        spin_unlock(&drvdata->spinlock);

        dev_info(drvdata->dev, "ETM tracing enabled\n");
        return 0;

err:
        spin_unlock(&drvdata->spinlock);
        return ret;
}

static int etm4_enable(struct coresight_device *csdev,
                       struct perf_event_attr *attr, u32 mode)
{
        int ret;
        u32 val;
        struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

        val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);

        /* Someone is already using the tracer */
        if (val)
                return -EBUSY;

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

        /* The tracer didn't start */
        if (ret)
                local_set(&drvdata->mode, CS_MODE_DISABLED);

        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 int etm4_disable_perf(struct coresight_device *csdev)
{
        struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

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

        etm4_disable_hw(drvdata);
        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.
         */
        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);

        spin_unlock(&drvdata->spinlock);
        put_online_cpus();

        dev_info(drvdata->dev, "ETM tracing disabled\n");
}

static void etm4_disable(struct coresight_device *csdev)
{
        u32 mode;
        struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

        /*
         * For as long as the tracer isn't disabled another entity can't
         * change its status.  As such we can read the status here without
         * fearing it will change under us.
         */
        mode = local_read(&drvdata->mode);

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

        if (mode)
                local_set(&drvdata->mode, CS_MODE_DISABLED);
}

static const struct coresight_ops_source etm4_source_ops = {
        .cpu_id         = etm4_cpu_id,
        .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 void etm4_init_arch_data(void *info)
{
        u32 etmidr0;
        u32 etmidr1;
        u32 etmidr2;
        u32 etmidr3;
        u32 etmidr4;
        u32 etmidr5;
        struct etmv4_drvdata *drvdata = info;

        /* Make sure all registers are accessible */
        etm4_os_unlock(drvdata);

        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 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.
         */
        drvdata->nr_resource = BMVAL(etmidr4, 16, 19) + 1;
        /*
         * 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_set_default(struct etmv4_config *config)
{
        if (WARN_ON_ONCE(!config))
                return;

        /*
         * Make default initialisation trace everything
         *
         * Select the "always true" resource selector on the
         * "Enablign Event" line and configure address range comparator
         * '0' to trace all the possible address range.  From there
         * configure the "include/exclude" engine to include address
         * range comparator '0'.
         */

        /* 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 |= BIT(0);

        /*
         * TRCVICTLR::SSSTATUS == 1, the start-stop logic is
         * in the started state
         */
        config->vinst_ctrl |= BIT(9);

        /*
         * Configure address range comparator '0' to encompass all
         * possible addresses.
         */

        /* First half of default address comparator: start at address 0 */
        config->addr_val[ETM_DEFAULT_ADDR_COMP] = 0x0;
        /* trace instruction addresses */
        config->addr_acc[ETM_DEFAULT_ADDR_COMP] &= ~(BIT(0) | BIT(1));
        /* EXLEVEL_NS, bits[12:15], only trace application and kernel space */
        config->addr_acc[ETM_DEFAULT_ADDR_COMP] |= ETM_EXLEVEL_NS_HYP;
        /* EXLEVEL_S, bits[11:8], don't trace anything in secure state */
        config->addr_acc[ETM_DEFAULT_ADDR_COMP] |= (ETM_EXLEVEL_S_APP |
                                                    ETM_EXLEVEL_S_OS |
                                                    ETM_EXLEVEL_S_HYP);
        config->addr_type[ETM_DEFAULT_ADDR_COMP] = ETM_ADDR_TYPE_RANGE;

        /*
         * Second half of default address comparator: go all
         * the way to the top.
        */
        config->addr_val[ETM_DEFAULT_ADDR_COMP + 1] = ~0x0;
        /* trace instruction addresses */
        config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] &= ~(BIT(0) | BIT(1));
        /* Address comparator type must be equal for both halves */
        config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] =
                                        config->addr_acc[ETM_DEFAULT_ADDR_COMP];
        config->addr_type[ETM_DEFAULT_ADDR_COMP + 1] = ETM_ADDR_TYPE_RANGE;

        /*
         * Configure the ViewInst function to filter on address range
         * comparator '0'.
         */
        config->viiectlr = BIT(0);

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

void etm4_config_trace_mode(struct etmv4_config *config)
{
        u32 addr_acc, 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;

        addr_acc = config->addr_acc[ETM_DEFAULT_ADDR_COMP];
        /* clear default config */
        addr_acc &= ~(ETM_EXLEVEL_NS_APP | ETM_EXLEVEL_NS_OS);

        /*
         * EXLEVEL_NS, bits[15:12]
         * The Exception levels are:
         *   Bit[12] Exception level 0 - Application
         *   Bit[13] Exception level 1 - OS
         *   Bit[14] Exception level 2 - Hypervisor
         *   Bit[15] Never implemented
         */
        if (mode & ETM_MODE_EXCL_KERN)
                addr_acc |= ETM_EXLEVEL_NS_OS;
        else
                addr_acc |= ETM_EXLEVEL_NS_APP;

        config->addr_acc[ETM_DEFAULT_ADDR_COMP] = addr_acc;
        config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] = addr_acc;
}

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 (local_read(&etmdrvdata[cpu]->mode))
                        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 (local_read(&etmdrvdata[cpu]->mode))
                        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 void etm4_init_trace_id(struct etmv4_drvdata *drvdata)
{
        drvdata->trcid = coresight_get_trace_id(drvdata->cpu);
}

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_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_trace_id(drvdata);
        etm4_set_default(&drvdata->config);

        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_arch_supported;
        }

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

        pm_runtime_put(&adev->dev);
        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:
        if (--etm4_count == 0)
                unregister_hotcpu_notifier(&etm4_cpu_notifier);
        return ret;
}

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",
        },
        {       /* ETM 4.0 - A72, Maia, HiSilicon */
                .id = 0x000bb95a,
                .mask = 0x000fffff,
                .data = "ETM 4.0",
        },
        { 0, 0},
};

static struct amba_driver etm4x_driver = {
        .drv = {
                .name   = "coresight-etm4x",
                .suppress_bind_attrs = true,
        },
        .probe          = etm4_probe,
        .id_table       = etm4_ids,
};
builtin_amba_driver(etm4x_driver);