// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2018 Linaro Limited, All rights reserved.
 * Author: Mike Leach <mike.leach@linaro.org>
 */

#include <linux/amba/bus.h>
#include <linux/atomic.h>
#include <linux/bits.h>
#include <linux/coresight.h>
#include <linux/cpu_pm.h>
#include <linux/cpuhotplug.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/spinlock.h>

#include "coresight-priv.h"
#include "coresight-cti.h"

/**
 * CTI devices can be associated with a PE, or be connected to CoreSight
 * hardware. We have a list of all CTIs irrespective of CPU bound or
 * otherwise.
 *
 * We assume that the non-CPU CTIs are always powered as we do with sinks etc.
 *
 * We leave the client to figure out if all the CTIs are interconnected with
 * the same CTM, in general this is the case but does not always have to be.
 */

/* net of CTI devices connected via CTM */
static LIST_HEAD(ect_net);

/* protect the list */
static DEFINE_MUTEX(ect_mutex);

#define csdev_to_cti_drvdata(csdev)     \
        dev_get_drvdata(csdev->dev.parent)

/* power management handling */
static int nr_cti_cpu;

/* quick lookup list for CPU bound CTIs when power handling */
static struct cti_drvdata *cti_cpu_drvdata[NR_CPUS];

/*
 * CTI naming. CTI bound to cores will have the name cti_cpu<N> where
 * N is the CPU ID. System CTIs will have the name cti_sys<I> where I
 * is an index allocated by order of discovery.
 *
 * CTI device name list - for CTI not bound to cores.
 */
DEFINE_CORESIGHT_DEVLIST(cti_sys_devs, "cti_sys");

/* write set of regs to hardware - call with spinlock claimed */
void cti_write_all_hw_regs(struct cti_drvdata *drvdata)
{
        struct cti_config *config = &drvdata->config;
        int i;

        CS_UNLOCK(drvdata->base);

        /* disable CTI before writing registers */
        writel_relaxed(0, drvdata->base + CTICONTROL);

        /* write the CTI trigger registers */
        for (i = 0; i < config->nr_trig_max; i++) {
                writel_relaxed(config->ctiinen[i], drvdata->base + CTIINEN(i));
                writel_relaxed(config->ctiouten[i],
                               drvdata->base + CTIOUTEN(i));
        }

        /* other regs */
        writel_relaxed(config->ctigate, drvdata->base + CTIGATE);
        writel_relaxed(config->asicctl, drvdata->base + ASICCTL);
        writel_relaxed(config->ctiappset, drvdata->base + CTIAPPSET);

        /* re-enable CTI */
        writel_relaxed(1, drvdata->base + CTICONTROL);

        CS_LOCK(drvdata->base);
}

/* write regs to hardware and enable */
static int cti_enable_hw(struct cti_drvdata *drvdata)
{
        struct cti_config *config = &drvdata->config;
        struct device *dev = &drvdata->csdev->dev;
        unsigned long flags;
        int rc = 0;

        pm_runtime_get_sync(dev->parent);
        spin_lock_irqsave(&drvdata->spinlock, flags);

        /* no need to do anything if enabled or unpowered*/
        if (config->hw_enabled || !config->hw_powered)
                goto cti_state_unchanged;

        /* claim the device */
        rc = coresight_claim_device(drvdata->csdev);
        if (rc)
                goto cti_err_not_enabled;

        cti_write_all_hw_regs(drvdata);

        config->hw_enabled = true;
        atomic_inc(&drvdata->config.enable_req_count);
        spin_unlock_irqrestore(&drvdata->spinlock, flags);
        return rc;

cti_state_unchanged:
        atomic_inc(&drvdata->config.enable_req_count);

        /* cannot enable due to error */
cti_err_not_enabled:
        spin_unlock_irqrestore(&drvdata->spinlock, flags);
        pm_runtime_put(dev->parent);
        return rc;
}

/* re-enable CTI on CPU when using CPU hotplug */
static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata)
{
        struct cti_config *config = &drvdata->config;

        spin_lock(&drvdata->spinlock);
        config->hw_powered = true;

        /* no need to do anything if no enable request */
        if (!atomic_read(&drvdata->config.enable_req_count))
                goto cti_hp_not_enabled;

        /* try to claim the device */
        if (coresight_claim_device(drvdata->csdev))
                goto cti_hp_not_enabled;

        cti_write_all_hw_regs(drvdata);
        config->hw_enabled = true;
        spin_unlock(&drvdata->spinlock);
        return;

        /* did not re-enable due to no claim / no request */
cti_hp_not_enabled:
        spin_unlock(&drvdata->spinlock);
}

/* disable hardware */
static int cti_disable_hw(struct cti_drvdata *drvdata)
{
        struct cti_config *config = &drvdata->config;
        struct device *dev = &drvdata->csdev->dev;
        struct coresight_device *csdev = drvdata->csdev;

        spin_lock(&drvdata->spinlock);

        /* check refcount - disable on 0 */
        if (atomic_dec_return(&drvdata->config.enable_req_count) > 0)
                goto cti_not_disabled;

        /* no need to do anything if disabled or cpu unpowered */
        if (!config->hw_enabled || !config->hw_powered)
                goto cti_not_disabled;

        CS_UNLOCK(drvdata->base);

        /* disable CTI */
        writel_relaxed(0, drvdata->base + CTICONTROL);
        config->hw_enabled = false;

        coresight_disclaim_device_unlocked(csdev);
        CS_LOCK(drvdata->base);
        spin_unlock(&drvdata->spinlock);
        pm_runtime_put(dev);
        return 0;

        /* not disabled this call */
cti_not_disabled:
        spin_unlock(&drvdata->spinlock);
        return 0;
}

void cti_write_single_reg(struct cti_drvdata *drvdata, int offset, u32 value)
{
        CS_UNLOCK(drvdata->base);
        writel_relaxed(value, drvdata->base + offset);
        CS_LOCK(drvdata->base);
}

void cti_write_intack(struct device *dev, u32 ackval)
{
        struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
        struct cti_config *config = &drvdata->config;

        spin_lock(&drvdata->spinlock);
        /* write if enabled */
        if (cti_active(config))
                cti_write_single_reg(drvdata, CTIINTACK, ackval);
        spin_unlock(&drvdata->spinlock);
}

/*
 * Look at the HW DEVID register for some of the HW settings.
 * DEVID[15:8] - max number of in / out triggers.
 */
#define CTI_DEVID_MAXTRIGS(devid_val) ((int) BMVAL(devid_val, 8, 15))

/* DEVID[19:16] - number of CTM channels */
#define CTI_DEVID_CTMCHANNELS(devid_val) ((int) BMVAL(devid_val, 16, 19))

static void cti_set_default_config(struct device *dev,
                                   struct cti_drvdata *drvdata)
{
        struct cti_config *config = &drvdata->config;
        u32 devid;

        devid = readl_relaxed(drvdata->base + CORESIGHT_DEVID);
        config->nr_trig_max = CTI_DEVID_MAXTRIGS(devid);

        /*
         * no current hardware should exceed this, but protect the driver
         * in case of fault / out of spec hw
         */
        if (config->nr_trig_max > CTIINOUTEN_MAX) {
                dev_warn_once(dev,
                        "Limiting HW MaxTrig value(%d) to driver max(%d)\n",
                        config->nr_trig_max, CTIINOUTEN_MAX);
                config->nr_trig_max = CTIINOUTEN_MAX;
        }

        config->nr_ctm_channels = CTI_DEVID_CTMCHANNELS(devid);

        /* Most regs default to 0 as zalloc'ed except...*/
        config->trig_filter_enable = true;
        config->ctigate = GENMASK(config->nr_ctm_channels - 1, 0);
        atomic_set(&config->enable_req_count, 0);
}

/*
 * Add a connection entry to the list of connections for this
 * CTI device.
 */
int cti_add_connection_entry(struct device *dev, struct cti_drvdata *drvdata,
                             struct cti_trig_con *tc,
                             struct coresight_device *csdev,
                             const char *assoc_dev_name)
{
        struct cti_device *cti_dev = &drvdata->ctidev;

        tc->con_dev = csdev;
        /*
         * Prefer actual associated CS device dev name to supplied value -
         * which is likely to be node name / other conn name.
         */
        if (csdev)
                tc->con_dev_name = dev_name(&csdev->dev);
        else if (assoc_dev_name != NULL) {
                tc->con_dev_name = devm_kstrdup(dev,
                                                assoc_dev_name, GFP_KERNEL);
                if (!tc->con_dev_name)
                        return -ENOMEM;
        }
        list_add_tail(&tc->node, &cti_dev->trig_cons);
        cti_dev->nr_trig_con++;

        /* add connection usage bit info to overall info */
        drvdata->config.trig_in_use |= tc->con_in->used_mask;
        drvdata->config.trig_out_use |= tc->con_out->used_mask;

        return 0;
}

/* create a trigger connection with appropriately sized signal groups */
struct cti_trig_con *cti_allocate_trig_con(struct device *dev, int in_sigs,
                                           int out_sigs)
{
        struct cti_trig_con *tc = NULL;
        struct cti_trig_grp *in = NULL, *out = NULL;

        tc = devm_kzalloc(dev, sizeof(struct cti_trig_con), GFP_KERNEL);
        if (!tc)
                return tc;

        in = devm_kzalloc(dev,
                          offsetof(struct cti_trig_grp, sig_types[in_sigs]),
                          GFP_KERNEL);
        if (!in)
                return NULL;

        out = devm_kzalloc(dev,
                           offsetof(struct cti_trig_grp, sig_types[out_sigs]),
                           GFP_KERNEL);
        if (!out)
                return NULL;

        tc->con_in = in;
        tc->con_out = out;
        tc->con_in->nr_sigs = in_sigs;
        tc->con_out->nr_sigs = out_sigs;
        return tc;
}

/*
 * Add a default connection if nothing else is specified.
 * single connection based on max in/out info, no assoc device
 */
int cti_add_default_connection(struct device *dev, struct cti_drvdata *drvdata)
{
        int ret = 0;
        int n_trigs = drvdata->config.nr_trig_max;
        u32 n_trig_mask = GENMASK(n_trigs - 1, 0);
        struct cti_trig_con *tc = NULL;

        /*
         * Assume max trigs for in and out,
         * all used, default sig types allocated
         */
        tc = cti_allocate_trig_con(dev, n_trigs, n_trigs);
        if (!tc)
                return -ENOMEM;

        tc->con_in->used_mask = n_trig_mask;
        tc->con_out->used_mask = n_trig_mask;
        ret = cti_add_connection_entry(dev, drvdata, tc, NULL, "default");
        return ret;
}

/** cti channel api **/
/* attach/detach channel from trigger - write through if enabled. */
int cti_channel_trig_op(struct device *dev, enum cti_chan_op op,
                        enum cti_trig_dir direction, u32 channel_idx,
                        u32 trigger_idx)
{
        struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
        struct cti_config *config = &drvdata->config;
        u32 trig_bitmask;
        u32 chan_bitmask;
        u32 reg_value;
        int reg_offset;

        /* ensure indexes in range */
        if ((channel_idx >= config->nr_ctm_channels) ||
           (trigger_idx >= config->nr_trig_max))
                return -EINVAL;

        trig_bitmask = BIT(trigger_idx);

        /* ensure registered triggers and not out filtered */
        if (direction == CTI_TRIG_IN)   {
                if (!(trig_bitmask & config->trig_in_use))
                        return -EINVAL;
        } else {
                if (!(trig_bitmask & config->trig_out_use))
                        return -EINVAL;

                if ((config->trig_filter_enable) &&
                    (config->trig_out_filter & trig_bitmask))
                        return -EINVAL;
        }

        /* update the local register values */
        chan_bitmask = BIT(channel_idx);
        reg_offset = (direction == CTI_TRIG_IN ? CTIINEN(trigger_idx) :
                      CTIOUTEN(trigger_idx));

        spin_lock(&drvdata->spinlock);

        /* read - modify write - the trigger / channel enable value */
        reg_value = direction == CTI_TRIG_IN ? config->ctiinen[trigger_idx] :
                     config->ctiouten[trigger_idx];
        if (op == CTI_CHAN_ATTACH)
                reg_value |= chan_bitmask;
        else
                reg_value &= ~chan_bitmask;

        /* write local copy */
        if (direction == CTI_TRIG_IN)
                config->ctiinen[trigger_idx] = reg_value;
        else
                config->ctiouten[trigger_idx] = reg_value;

        /* write through if enabled */
        if (cti_active(config))
                cti_write_single_reg(drvdata, reg_offset, reg_value);
        spin_unlock(&drvdata->spinlock);
        return 0;
}

int cti_channel_gate_op(struct device *dev, enum cti_chan_gate_op op,
                        u32 channel_idx)
{
        struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
        struct cti_config *config = &drvdata->config;
        u32 chan_bitmask;
        u32 reg_value;
        int err = 0;

        if (channel_idx >= config->nr_ctm_channels)
                return -EINVAL;

        chan_bitmask = BIT(channel_idx);

        spin_lock(&drvdata->spinlock);
        reg_value = config->ctigate;
        switch (op) {
        case CTI_GATE_CHAN_ENABLE:
                reg_value |= chan_bitmask;
                break;

        case CTI_GATE_CHAN_DISABLE:
                reg_value &= ~chan_bitmask;
                break;

        default:
                err = -EINVAL;
                break;
        }
        if (err == 0) {
                config->ctigate = reg_value;
                if (cti_active(config))
                        cti_write_single_reg(drvdata, CTIGATE, reg_value);
        }
        spin_unlock(&drvdata->spinlock);
        return err;
}

int cti_channel_setop(struct device *dev, enum cti_chan_set_op op,
                      u32 channel_idx)
{
        struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
        struct cti_config *config = &drvdata->config;
        u32 chan_bitmask;
        u32 reg_value;
        u32 reg_offset;
        int err = 0;

        if (channel_idx >= config->nr_ctm_channels)
                return -EINVAL;

        chan_bitmask = BIT(channel_idx);

        spin_lock(&drvdata->spinlock);
        reg_value = config->ctiappset;
        switch (op) {
        case CTI_CHAN_SET:
                config->ctiappset |= chan_bitmask;
                reg_value  = config->ctiappset;
                reg_offset = CTIAPPSET;
                break;

        case CTI_CHAN_CLR:
                config->ctiappset &= ~chan_bitmask;
                reg_value = chan_bitmask;
                reg_offset = CTIAPPCLEAR;
                break;

        case CTI_CHAN_PULSE:
                config->ctiappset &= ~chan_bitmask;
                reg_value = chan_bitmask;
                reg_offset = CTIAPPPULSE;
                break;

        default:
                err = -EINVAL;
                break;
        }

        if ((err == 0) && cti_active(config))
                cti_write_single_reg(drvdata, reg_offset, reg_value);
        spin_unlock(&drvdata->spinlock);

        return err;
}

static bool cti_add_sysfs_link(struct cti_drvdata *drvdata,
                               struct cti_trig_con *tc)
{
        struct coresight_sysfs_link link_info;
        int link_err = 0;

        link_info.orig = drvdata->csdev;
        link_info.orig_name = tc->con_dev_name;
        link_info.target = tc->con_dev;
        link_info.target_name = dev_name(&drvdata->csdev->dev);

        link_err = coresight_add_sysfs_link(&link_info);
        if (link_err)
                dev_warn(&drvdata->csdev->dev,
                         "Failed to set CTI sysfs link %s<=>%s\n",
                         link_info.orig_name, link_info.target_name);
        return !link_err;
}

static void cti_remove_sysfs_link(struct cti_drvdata *drvdata,
                                  struct cti_trig_con *tc)
{
        struct coresight_sysfs_link link_info;

        link_info.orig = drvdata->csdev;
        link_info.orig_name = tc->con_dev_name;
        link_info.target = tc->con_dev;
        link_info.target_name = dev_name(&drvdata->csdev->dev);
        coresight_remove_sysfs_link(&link_info);
}

/*
 * Look for a matching connection device name in the list of connections.
 * If found then swap in the csdev name, set trig con association pointer
 * and return found.
 */
static bool
cti_match_fixup_csdev(struct cti_device *ctidev, const char *node_name,
                      struct coresight_device *csdev)
{
        struct cti_trig_con *tc;
        struct cti_drvdata *drvdata = container_of(ctidev, struct cti_drvdata,
                                                   ctidev);

        list_for_each_entry(tc, &ctidev->trig_cons, node) {
                if (tc->con_dev_name) {
                        if (!strcmp(node_name, tc->con_dev_name)) {
                                /* match: so swap in csdev name & dev */
                                tc->con_dev_name = dev_name(&csdev->dev);
                                tc->con_dev = csdev;
                                /* try to set sysfs link */
                                if (cti_add_sysfs_link(drvdata, tc))
                                        return true;
                                /* link failed - remove CTI reference */
                                tc->con_dev = NULL;
                                break;
                        }
                }
        }
        return false;
}

/*
 * Search the cti list to add an associated CTI into the supplied CS device
 * This will set the association if CTI declared before the CS device.
 * (called from coresight_register() with coresight_mutex locked).
 */
static void cti_add_assoc_to_csdev(struct coresight_device *csdev)
{
        struct cti_drvdata *ect_item;
        struct cti_device *ctidev;
        const char *node_name = NULL;

        /* protect the list */
        mutex_lock(&ect_mutex);

        /* exit if current is an ECT device.*/
        if ((csdev->type == CORESIGHT_DEV_TYPE_ECT) || list_empty(&ect_net))
                goto cti_add_done;

        /* if we didn't find the csdev previously we used the fwnode name */
        node_name = cti_plat_get_node_name(dev_fwnode(csdev->dev.parent));
        if (!node_name)
                goto cti_add_done;

        /* for each CTI in list... */
        list_for_each_entry(ect_item, &ect_net, node) {
                ctidev = &ect_item->ctidev;
                if (cti_match_fixup_csdev(ctidev, node_name, csdev)) {
                        /*
                         * if we found a matching csdev then update the ECT
                         * association pointer for the device with this CTI.
                         */
                        csdev->ect_dev = ect_item->csdev;
                        break;
                }
        }
cti_add_done:
        mutex_unlock(&ect_mutex);
}

/*
 * Removing the associated devices is easier.
 * A CTI will not have a value for csdev->ect_dev.
 */
static void cti_remove_assoc_from_csdev(struct coresight_device *csdev)
{
        struct cti_drvdata *ctidrv;
        struct cti_trig_con *tc;
        struct cti_device *ctidev;

        mutex_lock(&ect_mutex);
        if (csdev->ect_dev) {
                ctidrv = csdev_to_cti_drvdata(csdev->ect_dev);
                ctidev = &ctidrv->ctidev;
                list_for_each_entry(tc, &ctidev->trig_cons, node) {
                        if (tc->con_dev == csdev) {
                                cti_remove_sysfs_link(ctidrv, tc);
                                tc->con_dev = NULL;
                                break;
                        }
                }
                csdev->ect_dev = NULL;
        }
        mutex_unlock(&ect_mutex);
}

/*
 * Operations to add and remove associated CTI.
 * Register to coresight core driver as call back function.
 */
static struct cti_assoc_op cti_assoc_ops = {
        .add = cti_add_assoc_to_csdev,
        .remove = cti_remove_assoc_from_csdev
};

/*
 * Update the cross references where the associated device was found
 * while we were building the connection info. This will occur if the
 * assoc device was registered before the CTI.
 */
static void cti_update_conn_xrefs(struct cti_drvdata *drvdata)
{
        struct cti_trig_con *tc;
        struct cti_device *ctidev = &drvdata->ctidev;

        list_for_each_entry(tc, &ctidev->trig_cons, node) {
                if (tc->con_dev) {
                        /* if we can set the sysfs link */
                        if (cti_add_sysfs_link(drvdata, tc))
                                /* set the CTI/csdev association */
                                coresight_set_assoc_ectdev_mutex(tc->con_dev,
                                                         drvdata->csdev);
                        else
                                /* otherwise remove reference from CTI */
                                tc->con_dev = NULL;
                }
        }
}

static void cti_remove_conn_xrefs(struct cti_drvdata *drvdata)
{
        struct cti_trig_con *tc;
        struct cti_device *ctidev = &drvdata->ctidev;

        list_for_each_entry(tc, &ctidev->trig_cons, node) {
                if (tc->con_dev) {
                        coresight_set_assoc_ectdev_mutex(tc->con_dev,
                                                         NULL);
                        cti_remove_sysfs_link(drvdata, tc);
                        tc->con_dev = NULL;
                }
        }
}

/** cti PM callbacks **/
static int cti_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd,
                             void *v)
{
        struct cti_drvdata *drvdata;
        struct coresight_device *csdev;
        unsigned int cpu = smp_processor_id();
        int notify_res = NOTIFY_OK;

        if (!cti_cpu_drvdata[cpu])
                return NOTIFY_OK;

        drvdata = cti_cpu_drvdata[cpu];
        csdev = drvdata->csdev;

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

        spin_lock(&drvdata->spinlock);

        switch (cmd) {
        case CPU_PM_ENTER:
                /* CTI regs all static - we have a copy & nothing to save */
                drvdata->config.hw_powered = false;
                if (drvdata->config.hw_enabled)
                        coresight_disclaim_device(csdev);
                break;

        case CPU_PM_ENTER_FAILED:
                drvdata->config.hw_powered = true;
                if (drvdata->config.hw_enabled) {
                        if (coresight_claim_device(csdev))
                                drvdata->config.hw_enabled = false;
                }
                break;

        case CPU_PM_EXIT:
                /* write hardware registers to re-enable. */
                drvdata->config.hw_powered = true;
                drvdata->config.hw_enabled = false;

                /* check enable reference count to enable HW */
                if (atomic_read(&drvdata->config.enable_req_count)) {
                        /* check we can claim the device as we re-power */
                        if (coresight_claim_device(csdev))
                                goto cti_notify_exit;

                        drvdata->config.hw_enabled = true;
                        cti_write_all_hw_regs(drvdata);
                }
                break;

        default:
                notify_res = NOTIFY_DONE;
                break;
        }

cti_notify_exit:
        spin_unlock(&drvdata->spinlock);
        return notify_res;
}

static struct notifier_block cti_cpu_pm_nb = {
        .notifier_call = cti_cpu_pm_notify,
};

/* CPU HP handlers */
static int cti_starting_cpu(unsigned int cpu)
{
        struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];

        if (!drvdata)
                return 0;

        cti_cpuhp_enable_hw(drvdata);
        return 0;
}

static int cti_dying_cpu(unsigned int cpu)
{
        struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];

        if (!drvdata)
                return 0;

        spin_lock(&drvdata->spinlock);
        drvdata->config.hw_powered = false;
        if (drvdata->config.hw_enabled)
                coresight_disclaim_device(drvdata->csdev);
        spin_unlock(&drvdata->spinlock);
        return 0;
}

static int cti_pm_setup(struct cti_drvdata *drvdata)
{
        int ret;

        if (drvdata->ctidev.cpu == -1)
                return 0;

        if (nr_cti_cpu)
                goto done;

        cpus_read_lock();
        ret = cpuhp_setup_state_nocalls_cpuslocked(
                        CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
                        "arm/coresight_cti:starting",
                        cti_starting_cpu, cti_dying_cpu);
        if (ret) {
                cpus_read_unlock();
                return ret;
        }

        ret = cpu_pm_register_notifier(&cti_cpu_pm_nb);
        cpus_read_unlock();
        if (ret) {
                cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_CTI_STARTING);
                return ret;
        }

done:
        nr_cti_cpu++;
        cti_cpu_drvdata[drvdata->ctidev.cpu] = drvdata;

        return 0;
}

/* release PM registrations */
static void cti_pm_release(struct cti_drvdata *drvdata)
{
        if (drvdata->ctidev.cpu == -1)
                return;

        cti_cpu_drvdata[drvdata->ctidev.cpu] = NULL;
        if (--nr_cti_cpu == 0) {
                cpu_pm_unregister_notifier(&cti_cpu_pm_nb);
                cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_CTI_STARTING);
        }
}

/** cti ect operations **/
int cti_enable(struct coresight_device *csdev)
{
        struct cti_drvdata *drvdata = csdev_to_cti_drvdata(csdev);

        return cti_enable_hw(drvdata);
}

int cti_disable(struct coresight_device *csdev)
{
        struct cti_drvdata *drvdata = csdev_to_cti_drvdata(csdev);

        return cti_disable_hw(drvdata);
}

static const struct coresight_ops_ect cti_ops_ect = {
        .enable = cti_enable,
        .disable = cti_disable,
};

static const struct coresight_ops cti_ops = {
        .ect_ops = &cti_ops_ect,
};

/*
 * Free up CTI specific resources
 * called by dev->release, need to call down to underlying csdev release.
 */
static void cti_device_release(struct device *dev)
{
        struct cti_drvdata *drvdata = dev_get_drvdata(dev->parent);
        struct cti_drvdata *ect_item, *ect_tmp;

        mutex_lock(&ect_mutex);
        cti_pm_release(drvdata);

        /* remove from the list */
        list_for_each_entry_safe(ect_item, ect_tmp, &ect_net, node) {
                if (ect_item == drvdata) {
                        list_del(&ect_item->node);
                        break;
                }
        }
        mutex_unlock(&ect_mutex);

        if (drvdata->csdev_release)
                drvdata->csdev_release(dev);
}
static void cti_remove(struct amba_device *adev)
{
        struct cti_drvdata *drvdata = dev_get_drvdata(&adev->dev);

        mutex_lock(&ect_mutex);
        cti_remove_conn_xrefs(drvdata);
        mutex_unlock(&ect_mutex);

        coresight_unregister(drvdata->csdev);
}

static int cti_probe(struct amba_device *adev, const struct amba_id *id)
{
        int ret = 0;
        void __iomem *base;
        struct device *dev = &adev->dev;
        struct cti_drvdata *drvdata = NULL;
        struct coresight_desc cti_desc;
        struct coresight_platform_data *pdata = NULL;
        struct resource *res = &adev->res;

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

        /* 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;
        cti_desc.access = CSDEV_ACCESS_IOMEM(base);

        dev_set_drvdata(dev, drvdata);

        /* default CTI device info  */
        drvdata->ctidev.cpu = -1;
        drvdata->ctidev.nr_trig_con = 0;
        drvdata->ctidev.ctm_id = 0;
        INIT_LIST_HEAD(&drvdata->ctidev.trig_cons);

        spin_lock_init(&drvdata->spinlock);

        /* initialise CTI driver config values */
        cti_set_default_config(dev, drvdata);

        pdata = coresight_cti_get_platform_data(dev);
        if (IS_ERR(pdata)) {
                dev_err(dev, "coresight_cti_get_platform_data err\n");
                return  PTR_ERR(pdata);
        }

        /* default to powered - could change on PM notifications */
        drvdata->config.hw_powered = true;

        /* set up device name - will depend if cpu bound or otherwise */
        if (drvdata->ctidev.cpu >= 0)
                cti_desc.name = devm_kasprintf(dev, GFP_KERNEL, "cti_cpu%d",
                                               drvdata->ctidev.cpu);
        else
                cti_desc.name = coresight_alloc_device_name(&cti_sys_devs, dev);
        if (!cti_desc.name)
                return -ENOMEM;

        /* setup CPU power management handling for CPU bound CTI devices. */
        ret = cti_pm_setup(drvdata);
        if (ret)
                return ret;

        /* create dynamic attributes for connections */
        ret = cti_create_cons_sysfs(dev, drvdata);
        if (ret) {
                dev_err(dev, "%s: create dynamic sysfs entries failed\n",
                        cti_desc.name);
                goto pm_release;
        }

        /* set up coresight component description */
        cti_desc.pdata = pdata;
        cti_desc.type = CORESIGHT_DEV_TYPE_ECT;
        cti_desc.subtype.ect_subtype = CORESIGHT_DEV_SUBTYPE_ECT_CTI;
        cti_desc.ops = &cti_ops;
        cti_desc.groups = drvdata->ctidev.con_groups;
        cti_desc.dev = dev;
        drvdata->csdev = coresight_register(&cti_desc);
        if (IS_ERR(drvdata->csdev)) {
                ret = PTR_ERR(drvdata->csdev);
                goto pm_release;
        }

        /* add to list of CTI devices */
        mutex_lock(&ect_mutex);
        list_add(&drvdata->node, &ect_net);
        /* set any cross references */
        cti_update_conn_xrefs(drvdata);
        mutex_unlock(&ect_mutex);

        /* set up release chain */
        drvdata->csdev_release = drvdata->csdev->dev.release;
        drvdata->csdev->dev.release = cti_device_release;

        /* all done - dec pm refcount */
        pm_runtime_put(&adev->dev);
        dev_info(&drvdata->csdev->dev, "CTI initialized\n");
        return 0;

pm_release:
        cti_pm_release(drvdata);
        return ret;
}

static struct amba_cs_uci_id uci_id_cti[] = {
        {
                /*  CTI UCI data */
                .devarch        = 0x47701a14, /* CTI v2 */
                .devarch_mask   = 0xfff0ffff,
                .devtype        = 0x00000014, /* maj(0x4-debug) min(0x1-ECT) */
        }
};

static const struct amba_id cti_ids[] = {
        CS_AMBA_ID(0x000bb906), /* Coresight CTI (SoC 400), C-A72, C-A57 */
        CS_AMBA_ID(0x000bb922), /* CTI - C-A8 */
        CS_AMBA_ID(0x000bb9a8), /* CTI - C-A53 */
        CS_AMBA_ID(0x000bb9aa), /* CTI - C-A73 */
        CS_AMBA_UCI_ID(0x000bb9da, uci_id_cti), /* CTI - C-A35 */
        CS_AMBA_UCI_ID(0x000bb9ed, uci_id_cti), /* Coresight CTI (SoC 600) */
        { 0, 0},
};

MODULE_DEVICE_TABLE(amba, cti_ids);

static struct amba_driver cti_driver = {
        .drv = {
                .name   = "coresight-cti",
                .owner = THIS_MODULE,
                .suppress_bind_attrs = true,
        },
        .probe          = cti_probe,
        .remove         = cti_remove,
        .id_table       = cti_ids,
};

static int __init cti_init(void)
{
        int ret;

        ret = amba_driver_register(&cti_driver);
        if (ret)
                pr_info("Error registering cti driver\n");
        coresight_set_cti_ops(&cti_assoc_ops);
        return ret;
}

static void __exit cti_exit(void)
{
        coresight_remove_cti_ops();
        amba_driver_unregister(&cti_driver);

}

module_init(cti_init);
module_exit(cti_exit);

MODULE_AUTHOR("Mike Leach <mike.leach@linaro.org>");
MODULE_DESCRIPTION("Arm CoreSight CTI Driver");
MODULE_LICENSE("GPL v2");