rtlwifi: No need to export rtl_evm_dbm_jaguar anymore

[deliverable/linux.git] / drivers / bus / arm-cci.c

/*
 * CCI cache coherent interconnect driver
 *
 * Copyright (C) 2013 ARM Ltd.
 * Author: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/arm-cci.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include <asm/cacheflush.h>
#include <asm/smp_plat.h>

#define DRIVER_NAME             "CCI-400"
#define DRIVER_NAME_PMU         DRIVER_NAME " PMU"

#define CCI_PORT_CTRL           0x0
#define CCI_CTRL_STATUS         0xc

#define CCI_ENABLE_SNOOP_REQ    0x1
#define CCI_ENABLE_DVM_REQ      0x2
#define CCI_ENABLE_REQ          (CCI_ENABLE_SNOOP_REQ | CCI_ENABLE_DVM_REQ)

struct cci_nb_ports {
        unsigned int nb_ace;
        unsigned int nb_ace_lite;
};

enum cci_ace_port_type {
        ACE_INVALID_PORT = 0x0,
        ACE_PORT,
        ACE_LITE_PORT,
};

struct cci_ace_port {
        void __iomem *base;
        unsigned long phys;
        enum cci_ace_port_type type;
        struct device_node *dn;
};

static struct cci_ace_port *ports;
static unsigned int nb_cci_ports;

static void __iomem *cci_ctrl_base;
static unsigned long cci_ctrl_phys;

#ifdef CONFIG_HW_PERF_EVENTS

#define CCI_PMCR                0x0100
#define CCI_PID2                0x0fe8

#define CCI_PMCR_CEN            0x00000001
#define CCI_PMCR_NCNT_MASK      0x0000f800
#define CCI_PMCR_NCNT_SHIFT     11

#define CCI_PID2_REV_MASK       0xf0
#define CCI_PID2_REV_SHIFT      4

/* Port ids */
#define CCI_PORT_S0     0
#define CCI_PORT_S1     1
#define CCI_PORT_S2     2
#define CCI_PORT_S3     3
#define CCI_PORT_S4     4
#define CCI_PORT_M0     5
#define CCI_PORT_M1     6
#define CCI_PORT_M2     7

#define CCI_REV_R0              0
#define CCI_REV_R1              1
#define CCI_REV_R1_PX           5

#define CCI_PMU_EVT_SEL         0x000
#define CCI_PMU_CNTR            0x004
#define CCI_PMU_CNTR_CTRL       0x008
#define CCI_PMU_OVRFLW          0x00c

#define CCI_PMU_OVRFLW_FLAG     1

#define CCI_PMU_CNTR_BASE(idx)  ((idx) * SZ_4K)

#define CCI_PMU_CNTR_MASK       ((1ULL << 32) -1)

/*
 * Instead of an event id to monitor CCI cycles, a dedicated counter is
 * provided. Use 0xff to represent CCI cycles and hope that no future revisions
 * make use of this event in hardware.
 */
enum cci400_perf_events {
        CCI_PMU_CYCLES = 0xff
};

#define CCI_PMU_EVENT_MASK              0xff
#define CCI_PMU_EVENT_SOURCE(event)     ((event >> 5) & 0x7)
#define CCI_PMU_EVENT_CODE(event)       (event & 0x1f)

#define CCI_PMU_MAX_HW_EVENTS 5   /* CCI PMU has 4 counters + 1 cycle counter */

#define CCI_PMU_CYCLE_CNTR_IDX          0
#define CCI_PMU_CNTR0_IDX               1
#define CCI_PMU_CNTR_LAST(cci_pmu)      (CCI_PMU_CYCLE_CNTR_IDX + cci_pmu->num_events - 1)

/*
 * CCI PMU event id is an 8-bit value made of two parts - bits 7:5 for one of 8
 * ports and bits 4:0 are event codes. There are different event codes
 * associated with each port type.
 *
 * Additionally, the range of events associated with the port types changed
 * between Rev0 and Rev1.
 *
 * The constants below define the range of valid codes for each port type for
 * the different revisions and are used to validate the event to be monitored.
 */

#define CCI_REV_R0_SLAVE_PORT_MIN_EV    0x00
#define CCI_REV_R0_SLAVE_PORT_MAX_EV    0x13
#define CCI_REV_R0_MASTER_PORT_MIN_EV   0x14
#define CCI_REV_R0_MASTER_PORT_MAX_EV   0x1a

#define CCI_REV_R1_SLAVE_PORT_MIN_EV    0x00
#define CCI_REV_R1_SLAVE_PORT_MAX_EV    0x14
#define CCI_REV_R1_MASTER_PORT_MIN_EV   0x00
#define CCI_REV_R1_MASTER_PORT_MAX_EV   0x11

struct pmu_port_event_ranges {
        u8 slave_min;
        u8 slave_max;
        u8 master_min;
        u8 master_max;
};

static struct pmu_port_event_ranges port_event_range[] = {
        [CCI_REV_R0] = {
                .slave_min = CCI_REV_R0_SLAVE_PORT_MIN_EV,
                .slave_max = CCI_REV_R0_SLAVE_PORT_MAX_EV,
                .master_min = CCI_REV_R0_MASTER_PORT_MIN_EV,
                .master_max = CCI_REV_R0_MASTER_PORT_MAX_EV,
        },
        [CCI_REV_R1] = {
                .slave_min = CCI_REV_R1_SLAVE_PORT_MIN_EV,
                .slave_max = CCI_REV_R1_SLAVE_PORT_MAX_EV,
                .master_min = CCI_REV_R1_MASTER_PORT_MIN_EV,
                .master_max = CCI_REV_R1_MASTER_PORT_MAX_EV,
        },
};

/*
 * Export different PMU names for the different revisions so userspace knows
 * because the event ids are different
 */
static char *const pmu_names[] = {
        [CCI_REV_R0] = "CCI_400",
        [CCI_REV_R1] = "CCI_400_r1",
};

struct cci_pmu_hw_events {
        struct perf_event *events[CCI_PMU_MAX_HW_EVENTS];
        unsigned long used_mask[BITS_TO_LONGS(CCI_PMU_MAX_HW_EVENTS)];
        raw_spinlock_t pmu_lock;
};

struct cci_pmu {
        void __iomem *base;
        struct pmu pmu;
        int nr_irqs;
        int irqs[CCI_PMU_MAX_HW_EVENTS];
        unsigned long active_irqs;
        struct pmu_port_event_ranges *port_ranges;
        struct cci_pmu_hw_events hw_events;
        struct platform_device *plat_device;
        int num_events;
        atomic_t active_events;
        struct mutex reserve_mutex;
        cpumask_t cpus;
};
static struct cci_pmu *pmu;

#define to_cci_pmu(c)   (container_of(c, struct cci_pmu, pmu))

static bool is_duplicate_irq(int irq, int *irqs, int nr_irqs)
{
        int i;

        for (i = 0; i < nr_irqs; i++)
                if (irq == irqs[i])
                        return true;

        return false;
}

static int probe_cci_revision(void)
{
        int rev;
        rev = readl_relaxed(cci_ctrl_base + CCI_PID2) & CCI_PID2_REV_MASK;
        rev >>= CCI_PID2_REV_SHIFT;

        if (rev < CCI_REV_R1_PX)
                return CCI_REV_R0;
        else
                return CCI_REV_R1;
}

static struct pmu_port_event_ranges *port_range_by_rev(void)
{
        int rev = probe_cci_revision();

        return &port_event_range[rev];
}

static int pmu_is_valid_slave_event(u8 ev_code)
{
        return pmu->port_ranges->slave_min <= ev_code &&
                ev_code <= pmu->port_ranges->slave_max;
}

static int pmu_is_valid_master_event(u8 ev_code)
{
        return pmu->port_ranges->master_min <= ev_code &&
                ev_code <= pmu->port_ranges->master_max;
}

static int pmu_validate_hw_event(u8 hw_event)
{
        u8 ev_source = CCI_PMU_EVENT_SOURCE(hw_event);
        u8 ev_code = CCI_PMU_EVENT_CODE(hw_event);

        switch (ev_source) {
        case CCI_PORT_S0:
        case CCI_PORT_S1:
        case CCI_PORT_S2:
        case CCI_PORT_S3:
        case CCI_PORT_S4:
                /* Slave Interface */
                if (pmu_is_valid_slave_event(ev_code))
                        return hw_event;
                break;
        case CCI_PORT_M0:
        case CCI_PORT_M1:
        case CCI_PORT_M2:
                /* Master Interface */
                if (pmu_is_valid_master_event(ev_code))
                        return hw_event;
                break;
        }

        return -ENOENT;
}

static int pmu_is_valid_counter(struct cci_pmu *cci_pmu, int idx)
{
        return CCI_PMU_CYCLE_CNTR_IDX <= idx &&
                idx <= CCI_PMU_CNTR_LAST(cci_pmu);
}

static u32 pmu_read_register(int idx, unsigned int offset)
{
        return readl_relaxed(pmu->base + CCI_PMU_CNTR_BASE(idx) + offset);
}

static void pmu_write_register(u32 value, int idx, unsigned int offset)
{
        return writel_relaxed(value, pmu->base + CCI_PMU_CNTR_BASE(idx) + offset);
}

static void pmu_disable_counter(int idx)
{
        pmu_write_register(0, idx, CCI_PMU_CNTR_CTRL);
}

static void pmu_enable_counter(int idx)
{
        pmu_write_register(1, idx, CCI_PMU_CNTR_CTRL);
}

static void pmu_set_event(int idx, unsigned long event)
{
        event &= CCI_PMU_EVENT_MASK;
        pmu_write_register(event, idx, CCI_PMU_EVT_SEL);
}

static u32 pmu_get_max_counters(void)
{
        u32 n_cnts = (readl_relaxed(cci_ctrl_base + CCI_PMCR) &
                      CCI_PMCR_NCNT_MASK) >> CCI_PMCR_NCNT_SHIFT;

        /* add 1 for cycle counter */
        return n_cnts + 1;
}

static int pmu_get_event_idx(struct cci_pmu_hw_events *hw, struct perf_event *event)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        struct hw_perf_event *hw_event = &event->hw;
        unsigned long cci_event = hw_event->config_base & CCI_PMU_EVENT_MASK;
        int idx;

        if (cci_event == CCI_PMU_CYCLES) {
                if (test_and_set_bit(CCI_PMU_CYCLE_CNTR_IDX, hw->used_mask))
                        return -EAGAIN;

                return CCI_PMU_CYCLE_CNTR_IDX;
        }

        for (idx = CCI_PMU_CNTR0_IDX; idx <= CCI_PMU_CNTR_LAST(cci_pmu); ++idx)
                if (!test_and_set_bit(idx, hw->used_mask))
                        return idx;

        /* No counters available */
        return -EAGAIN;
}

static int pmu_map_event(struct perf_event *event)
{
        int mapping;
        u8 config = event->attr.config & CCI_PMU_EVENT_MASK;

        if (event->attr.type < PERF_TYPE_MAX)
                return -ENOENT;

        if (config == CCI_PMU_CYCLES)
                mapping = config;
        else
                mapping = pmu_validate_hw_event(config);

        return mapping;
}

static int pmu_request_irq(struct cci_pmu *cci_pmu, irq_handler_t handler)
{
        int i;
        struct platform_device *pmu_device = cci_pmu->plat_device;

        if (unlikely(!pmu_device))
                return -ENODEV;

        if (pmu->nr_irqs < 1) {
                dev_err(&pmu_device->dev, "no irqs for CCI PMUs defined\n");
                return -ENODEV;
        }

        /*
         * Register all available CCI PMU interrupts. In the interrupt handler
         * we iterate over the counters checking for interrupt source (the
         * overflowing counter) and clear it.
         *
         * This should allow handling of non-unique interrupt for the counters.
         */
        for (i = 0; i < pmu->nr_irqs; i++) {
                int err = request_irq(pmu->irqs[i], handler, IRQF_SHARED,
                                "arm-cci-pmu", cci_pmu);
                if (err) {
                        dev_err(&pmu_device->dev, "unable to request IRQ%d for ARM CCI PMU counters\n",
                                pmu->irqs[i]);
                        return err;
                }

                set_bit(i, &pmu->active_irqs);
        }

        return 0;
}

static void pmu_free_irq(struct cci_pmu *cci_pmu)
{
        int i;

        for (i = 0; i < pmu->nr_irqs; i++) {
                if (!test_and_clear_bit(i, &pmu->active_irqs))
                        continue;

                free_irq(pmu->irqs[i], cci_pmu);
        }
}

static u32 pmu_read_counter(struct perf_event *event)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        struct hw_perf_event *hw_counter = &event->hw;
        int idx = hw_counter->idx;
        u32 value;

        if (unlikely(!pmu_is_valid_counter(cci_pmu, idx))) {
                dev_err(&cci_pmu->plat_device->dev, "Invalid CCI PMU counter %d\n", idx);
                return 0;
        }
        value = pmu_read_register(idx, CCI_PMU_CNTR);

        return value;
}

static void pmu_write_counter(struct perf_event *event, u32 value)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        struct hw_perf_event *hw_counter = &event->hw;
        int idx = hw_counter->idx;

        if (unlikely(!pmu_is_valid_counter(cci_pmu, idx)))
                dev_err(&cci_pmu->plat_device->dev, "Invalid CCI PMU counter %d\n", idx);
        else
                pmu_write_register(value, idx, CCI_PMU_CNTR);
}

static u64 pmu_event_update(struct perf_event *event)
{
        struct hw_perf_event *hwc = &event->hw;
        u64 delta, prev_raw_count, new_raw_count;

        do {
                prev_raw_count = local64_read(&hwc->prev_count);
                new_raw_count = pmu_read_counter(event);
        } while (local64_cmpxchg(&hwc->prev_count, prev_raw_count,
                 new_raw_count) != prev_raw_count);

        delta = (new_raw_count - prev_raw_count) & CCI_PMU_CNTR_MASK;

        local64_add(delta, &event->count);

        return new_raw_count;
}

static void pmu_read(struct perf_event *event)
{
        pmu_event_update(event);
}

void pmu_event_set_period(struct perf_event *event)
{
        struct hw_perf_event *hwc = &event->hw;
        /*
         * The CCI PMU counters have a period of 2^32. To account for the
         * possiblity of extreme interrupt latency we program for a period of
         * half that. Hopefully we can handle the interrupt before another 2^31
         * events occur and the counter overtakes its previous value.
         */
        u64 val = 1ULL << 31;
        local64_set(&hwc->prev_count, val);
        pmu_write_counter(event, val);
}

static irqreturn_t pmu_handle_irq(int irq_num, void *dev)
{
        unsigned long flags;
        struct cci_pmu *cci_pmu = dev;
        struct cci_pmu_hw_events *events = &pmu->hw_events;
        int idx, handled = IRQ_NONE;

        raw_spin_lock_irqsave(&events->pmu_lock, flags);
        /*
         * Iterate over counters and update the corresponding perf events.
         * This should work regardless of whether we have per-counter overflow
         * interrupt or a combined overflow interrupt.
         */
        for (idx = CCI_PMU_CYCLE_CNTR_IDX; idx <= CCI_PMU_CNTR_LAST(cci_pmu); idx++) {
                struct perf_event *event = events->events[idx];
                struct hw_perf_event *hw_counter;

                if (!event)
                        continue;

                hw_counter = &event->hw;

                /* Did this counter overflow? */
                if (!(pmu_read_register(idx, CCI_PMU_OVRFLW) &
                      CCI_PMU_OVRFLW_FLAG))
                        continue;

                pmu_write_register(CCI_PMU_OVRFLW_FLAG, idx, CCI_PMU_OVRFLW);

                pmu_event_update(event);
                pmu_event_set_period(event);
                handled = IRQ_HANDLED;
        }
        raw_spin_unlock_irqrestore(&events->pmu_lock, flags);

        return IRQ_RETVAL(handled);
}

static int cci_pmu_get_hw(struct cci_pmu *cci_pmu)
{
        int ret = pmu_request_irq(cci_pmu, pmu_handle_irq);
        if (ret) {
                pmu_free_irq(cci_pmu);
                return ret;
        }
        return 0;
}

static void cci_pmu_put_hw(struct cci_pmu *cci_pmu)
{
        pmu_free_irq(cci_pmu);
}

static void hw_perf_event_destroy(struct perf_event *event)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        atomic_t *active_events = &cci_pmu->active_events;
        struct mutex *reserve_mutex = &cci_pmu->reserve_mutex;

        if (atomic_dec_and_mutex_lock(active_events, reserve_mutex)) {
                cci_pmu_put_hw(cci_pmu);
                mutex_unlock(reserve_mutex);
        }
}

static void cci_pmu_enable(struct pmu *pmu)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(pmu);
        struct cci_pmu_hw_events *hw_events = &cci_pmu->hw_events;
        int enabled = bitmap_weight(hw_events->used_mask, cci_pmu->num_events);
        unsigned long flags;
        u32 val;

        if (!enabled)
                return;

        raw_spin_lock_irqsave(&hw_events->pmu_lock, flags);

        /* Enable all the PMU counters. */
        val = readl_relaxed(cci_ctrl_base + CCI_PMCR) | CCI_PMCR_CEN;
        writel(val, cci_ctrl_base + CCI_PMCR);
        raw_spin_unlock_irqrestore(&hw_events->pmu_lock, flags);

}

static void cci_pmu_disable(struct pmu *pmu)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(pmu);
        struct cci_pmu_hw_events *hw_events = &cci_pmu->hw_events;
        unsigned long flags;
        u32 val;

        raw_spin_lock_irqsave(&hw_events->pmu_lock, flags);

        /* Disable all the PMU counters. */
        val = readl_relaxed(cci_ctrl_base + CCI_PMCR) & ~CCI_PMCR_CEN;
        writel(val, cci_ctrl_base + CCI_PMCR);
        raw_spin_unlock_irqrestore(&hw_events->pmu_lock, flags);
}

static void cci_pmu_start(struct perf_event *event, int pmu_flags)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        struct cci_pmu_hw_events *hw_events = &cci_pmu->hw_events;
        struct hw_perf_event *hwc = &event->hw;
        int idx = hwc->idx;
        unsigned long flags;

        /*
         * To handle interrupt latency, we always reprogram the period
         * regardlesss of PERF_EF_RELOAD.
         */
        if (pmu_flags & PERF_EF_RELOAD)
                WARN_ON_ONCE(!(hwc->state & PERF_HES_UPTODATE));

        hwc->state = 0;

        if (unlikely(!pmu_is_valid_counter(cci_pmu, idx))) {
                dev_err(&cci_pmu->plat_device->dev, "Invalid CCI PMU counter %d\n", idx);
                return;
        }

        raw_spin_lock_irqsave(&hw_events->pmu_lock, flags);

        /* Configure the event to count, unless you are counting cycles */
        if (idx != CCI_PMU_CYCLE_CNTR_IDX)
                pmu_set_event(idx, hwc->config_base);

        pmu_event_set_period(event);
        pmu_enable_counter(idx);

        raw_spin_unlock_irqrestore(&hw_events->pmu_lock, flags);
}

static void cci_pmu_stop(struct perf_event *event, int pmu_flags)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        struct hw_perf_event *hwc = &event->hw;
        int idx = hwc->idx;

        if (hwc->state & PERF_HES_STOPPED)
                return;

        if (unlikely(!pmu_is_valid_counter(cci_pmu, idx))) {
                dev_err(&cci_pmu->plat_device->dev, "Invalid CCI PMU counter %d\n", idx);
                return;
        }

        /*
         * We always reprogram the counter, so ignore PERF_EF_UPDATE. See
         * cci_pmu_start()
         */
        pmu_disable_counter(idx);
        pmu_event_update(event);
        hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
}

static int cci_pmu_add(struct perf_event *event, int flags)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        struct cci_pmu_hw_events *hw_events = &cci_pmu->hw_events;
        struct hw_perf_event *hwc = &event->hw;
        int idx;
        int err = 0;

        perf_pmu_disable(event->pmu);

        /* If we don't have a space for the counter then finish early. */
        idx = pmu_get_event_idx(hw_events, event);
        if (idx < 0) {
                err = idx;
                goto out;
        }

        event->hw.idx = idx;
        hw_events->events[idx] = event;

        hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
        if (flags & PERF_EF_START)
                cci_pmu_start(event, PERF_EF_RELOAD);

        /* Propagate our changes to the userspace mapping. */
        perf_event_update_userpage(event);

out:
        perf_pmu_enable(event->pmu);
        return err;
}

static void cci_pmu_del(struct perf_event *event, int flags)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        struct cci_pmu_hw_events *hw_events = &cci_pmu->hw_events;
        struct hw_perf_event *hwc = &event->hw;
        int idx = hwc->idx;

        cci_pmu_stop(event, PERF_EF_UPDATE);
        hw_events->events[idx] = NULL;
        clear_bit(idx, hw_events->used_mask);

        perf_event_update_userpage(event);
}

static int
validate_event(struct cci_pmu_hw_events *hw_events,
               struct perf_event *event)
{
        if (is_software_event(event))
                return 1;

        if (event->state < PERF_EVENT_STATE_OFF)
                return 1;

        if (event->state == PERF_EVENT_STATE_OFF && !event->attr.enable_on_exec)
                return 1;

        return pmu_get_event_idx(hw_events, event) >= 0;
}

static int
validate_group(struct perf_event *event)
{
        struct perf_event *sibling, *leader = event->group_leader;
        struct cci_pmu_hw_events fake_pmu = {
                /*
                 * Initialise the fake PMU. We only need to populate the
                 * used_mask for the purposes of validation.
                 */
                .used_mask = CPU_BITS_NONE,
        };

        if (!validate_event(&fake_pmu, leader))
                return -EINVAL;

        list_for_each_entry(sibling, &leader->sibling_list, group_entry) {
                if (!validate_event(&fake_pmu, sibling))
                        return -EINVAL;
        }

        if (!validate_event(&fake_pmu, event))
                return -EINVAL;

        return 0;
}

static int
__hw_perf_event_init(struct perf_event *event)
{
        struct hw_perf_event *hwc = &event->hw;
        int mapping;

        mapping = pmu_map_event(event);

        if (mapping < 0) {
                pr_debug("event %x:%llx not supported\n", event->attr.type,
                         event->attr.config);
                return mapping;
        }

        /*
         * We don't assign an index until we actually place the event onto
         * hardware. Use -1 to signify that we haven't decided where to put it
         * yet.
         */
        hwc->idx                = -1;
        hwc->config_base        = 0;
        hwc->config             = 0;
        hwc->event_base         = 0;

        /*
         * Store the event encoding into the config_base field.
         */
        hwc->config_base            |= (unsigned long)mapping;

        /*
         * Limit the sample_period to half of the counter width. That way, the
         * new counter value is far less likely to overtake the previous one
         * unless you have some serious IRQ latency issues.
         */
        hwc->sample_period  = CCI_PMU_CNTR_MASK >> 1;
        hwc->last_period    = hwc->sample_period;
        local64_set(&hwc->period_left, hwc->sample_period);

        if (event->group_leader != event) {
                if (validate_group(event) != 0)
                        return -EINVAL;
        }

        return 0;
}

static int cci_pmu_event_init(struct perf_event *event)
{
        struct cci_pmu *cci_pmu = to_cci_pmu(event->pmu);
        atomic_t *active_events = &cci_pmu->active_events;
        int err = 0;
        int cpu;

        if (event->attr.type != event->pmu->type)
                return -ENOENT;

        /* Shared by all CPUs, no meaningful state to sample */
        if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
                return -EOPNOTSUPP;

        /* We have no filtering of any kind */
        if (event->attr.exclude_user    ||
            event->attr.exclude_kernel  ||
            event->attr.exclude_hv      ||
            event->attr.exclude_idle    ||
            event->attr.exclude_host    ||
            event->attr.exclude_guest)
                return -EINVAL;

        /*
         * Following the example set by other "uncore" PMUs, we accept any CPU
         * and rewrite its affinity dynamically rather than having perf core
         * handle cpu == -1 and pid == -1 for this case.
         *
         * The perf core will pin online CPUs for the duration of this call and
         * the event being installed into its context, so the PMU's CPU can't
         * change under our feet.
         */
        cpu = cpumask_first(&cci_pmu->cpus);
        if (event->cpu < 0 || cpu < 0)
                return -EINVAL;
        event->cpu = cpu;

        event->destroy = hw_perf_event_destroy;
        if (!atomic_inc_not_zero(active_events)) {
                mutex_lock(&cci_pmu->reserve_mutex);
                if (atomic_read(active_events) == 0)
                        err = cci_pmu_get_hw(cci_pmu);
                if (!err)
                        atomic_inc(active_events);
                mutex_unlock(&cci_pmu->reserve_mutex);
        }
        if (err)
                return err;

        err = __hw_perf_event_init(event);
        if (err)
                hw_perf_event_destroy(event);

        return err;
}

static ssize_t pmu_attr_cpumask_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        int n = scnprintf(buf, PAGE_SIZE - 1, "%*pbl",
                          cpumask_pr_args(&pmu->cpus));
        buf[n++] = '\n';
        buf[n] = '\0';
        return n;
}

static DEVICE_ATTR(cpumask, S_IRUGO, pmu_attr_cpumask_show, NULL);

static struct attribute *pmu_attrs[] = {
        &dev_attr_cpumask.attr,
        NULL,
};

static struct attribute_group pmu_attr_group = {
        .attrs = pmu_attrs,
};

static const struct attribute_group *pmu_attr_groups[] = {
        &pmu_attr_group,
        NULL
};

static int cci_pmu_init(struct cci_pmu *cci_pmu, struct platform_device *pdev)
{
        char *name = pmu_names[probe_cci_revision()];
        cci_pmu->pmu = (struct pmu) {
                .name           = pmu_names[probe_cci_revision()],
                .task_ctx_nr    = perf_invalid_context,
                .pmu_enable     = cci_pmu_enable,
                .pmu_disable    = cci_pmu_disable,
                .event_init     = cci_pmu_event_init,
                .add            = cci_pmu_add,
                .del            = cci_pmu_del,
                .start          = cci_pmu_start,
                .stop           = cci_pmu_stop,
                .read           = pmu_read,
                .attr_groups    = pmu_attr_groups,
        };

        cci_pmu->plat_device = pdev;
        cci_pmu->num_events = pmu_get_max_counters();

        return perf_pmu_register(&cci_pmu->pmu, name, -1);
}

static int cci_pmu_cpu_notifier(struct notifier_block *self,
                                unsigned long action, void *hcpu)
{
        unsigned int cpu = (long)hcpu;
        unsigned int target;

        switch (action & ~CPU_TASKS_FROZEN) {
        case CPU_DOWN_PREPARE:
                if (!cpumask_test_and_clear_cpu(cpu, &pmu->cpus))
                        break;
                target = cpumask_any_but(cpu_online_mask, cpu);
                if (target < 0) // UP, last CPU
                        break;
                /*
                 * TODO: migrate context once core races on event->ctx have
                 * been fixed.
                 */
                cpumask_set_cpu(target, &pmu->cpus);
        default:
                break;
        }

        return NOTIFY_OK;
}

static struct notifier_block cci_pmu_cpu_nb = {
        .notifier_call  = cci_pmu_cpu_notifier,
        /*
         * to migrate uncore events, our notifier should be executed
         * before perf core's notifier.
         */
        .priority       = CPU_PRI_PERF + 1,
};

static const struct of_device_id arm_cci_pmu_matches[] = {
        {
                .compatible = "arm,cci-400-pmu",
        },
        {},
};

static int cci_pmu_probe(struct platform_device *pdev)
{
        struct resource *res;
        int i, ret, irq;

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

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        pmu->base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(pmu->base))
                return -ENOMEM;

        /*
         * CCI PMU has 5 overflow signals - one per counter; but some may be tied
         * together to a common interrupt.
         */
        pmu->nr_irqs = 0;
        for (i = 0; i < CCI_PMU_MAX_HW_EVENTS; i++) {
                irq = platform_get_irq(pdev, i);
                if (irq < 0)
                        break;

                if (is_duplicate_irq(irq, pmu->irqs, pmu->nr_irqs))
                        continue;

                pmu->irqs[pmu->nr_irqs++] = irq;
        }

        /*
         * Ensure that the device tree has as many interrupts as the number
         * of counters.
         */
        if (i < CCI_PMU_MAX_HW_EVENTS) {
                dev_warn(&pdev->dev, "In-correct number of interrupts: %d, should be %d\n",
                        i, CCI_PMU_MAX_HW_EVENTS);
                return -EINVAL;
        }

        pmu->port_ranges = port_range_by_rev();
        if (!pmu->port_ranges) {
                dev_warn(&pdev->dev, "CCI PMU version not supported\n");
                return -EINVAL;
        }

        raw_spin_lock_init(&pmu->hw_events.pmu_lock);
        mutex_init(&pmu->reserve_mutex);
        atomic_set(&pmu->active_events, 0);
        cpumask_set_cpu(smp_processor_id(), &pmu->cpus);

        ret = register_cpu_notifier(&cci_pmu_cpu_nb);
        if (ret)
                return ret;

        ret = cci_pmu_init(pmu, pdev);
        if (ret)
                return ret;

        return 0;
}

static int cci_platform_probe(struct platform_device *pdev)
{
        if (!cci_probed())
                return -ENODEV;

        return of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
}

#endif /* CONFIG_HW_PERF_EVENTS */

struct cpu_port {
        u64 mpidr;
        u32 port;
};

/*
 * Use the port MSB as valid flag, shift can be made dynamic
 * by computing number of bits required for port indexes.
 * Code disabling CCI cpu ports runs with D-cache invalidated
 * and SCTLR bit clear so data accesses must be kept to a minimum
 * to improve performance; for now shift is left static to
 * avoid one more data access while disabling the CCI port.
 */
#define PORT_VALID_SHIFT        31
#define PORT_VALID              (0x1 << PORT_VALID_SHIFT)

static inline void init_cpu_port(struct cpu_port *port, u32 index, u64 mpidr)
{
        port->port = PORT_VALID | index;
        port->mpidr = mpidr;
}

static inline bool cpu_port_is_valid(struct cpu_port *port)
{
        return !!(port->port & PORT_VALID);
}

static inline bool cpu_port_match(struct cpu_port *port, u64 mpidr)
{
        return port->mpidr == (mpidr & MPIDR_HWID_BITMASK);
}

static struct cpu_port cpu_port[NR_CPUS];

/**
 * __cci_ace_get_port - Function to retrieve the port index connected to
 *                      a cpu or device.
 *
 * @dn: device node of the device to look-up
 * @type: port type
 *
 * Return value:
 *      - CCI port index if success
 *      - -ENODEV if failure
 */
static int __cci_ace_get_port(struct device_node *dn, int type)
{
        int i;
        bool ace_match;
        struct device_node *cci_portn;

        cci_portn = of_parse_phandle(dn, "cci-control-port", 0);
        for (i = 0; i < nb_cci_ports; i++) {
                ace_match = ports[i].type == type;
                if (ace_match && cci_portn == ports[i].dn)
                        return i;
        }
        return -ENODEV;
}

int cci_ace_get_port(struct device_node *dn)
{
        return __cci_ace_get_port(dn, ACE_LITE_PORT);
}
EXPORT_SYMBOL_GPL(cci_ace_get_port);

static void cci_ace_init_ports(void)
{
        int port, cpu;
        struct device_node *cpun;

        /*
         * Port index look-up speeds up the function disabling ports by CPU,
         * since the logical to port index mapping is done once and does
         * not change after system boot.
         * The stashed index array is initialized for all possible CPUs
         * at probe time.
         */
        for_each_possible_cpu(cpu) {
                /* too early to use cpu->of_node */
                cpun = of_get_cpu_node(cpu, NULL);

                if (WARN(!cpun, "Missing cpu device node\n"))
                        continue;

                port = __cci_ace_get_port(cpun, ACE_PORT);
                if (port < 0)
                        continue;

                init_cpu_port(&cpu_port[cpu], port, cpu_logical_map(cpu));
        }

        for_each_possible_cpu(cpu) {
                WARN(!cpu_port_is_valid(&cpu_port[cpu]),
                        "CPU %u does not have an associated CCI port\n",
                        cpu);
        }
}
/*
 * Functions to enable/disable a CCI interconnect slave port
 *
 * They are called by low-level power management code to disable slave
 * interfaces snoops and DVM broadcast.
 * Since they may execute with cache data allocation disabled and
 * after the caches have been cleaned and invalidated the functions provide
 * no explicit locking since they may run with D-cache disabled, so normal
 * cacheable kernel locks based on ldrex/strex may not work.
 * Locking has to be provided by BSP implementations to ensure proper
 * operations.
 */

/**
 * cci_port_control() - function to control a CCI port
 *
 * @port: index of the port to setup
 * @enable: if true enables the port, if false disables it
 */
static void notrace cci_port_control(unsigned int port, bool enable)
{
        void __iomem *base = ports[port].base;

        writel_relaxed(enable ? CCI_ENABLE_REQ : 0, base + CCI_PORT_CTRL);
        /*
         * This function is called from power down procedures
         * and must not execute any instruction that might
         * cause the processor to be put in a quiescent state
         * (eg wfi). Hence, cpu_relax() can not be added to this
         * read loop to optimize power, since it might hide possibly
         * disruptive operations.
         */
        while (readl_relaxed(cci_ctrl_base + CCI_CTRL_STATUS) & 0x1)
                        ;
}

/**
 * cci_disable_port_by_cpu() - function to disable a CCI port by CPU
 *                             reference
 *
 * @mpidr: mpidr of the CPU whose CCI port should be disabled
 *
 * Disabling a CCI port for a CPU implies disabling the CCI port
 * controlling that CPU cluster. Code disabling CPU CCI ports
 * must make sure that the CPU running the code is the last active CPU
 * in the cluster ie all other CPUs are quiescent in a low power state.
 *
 * Return:
 *      0 on success
 *      -ENODEV on port look-up failure
 */
int notrace cci_disable_port_by_cpu(u64 mpidr)
{
        int cpu;
        bool is_valid;
        for (cpu = 0; cpu < nr_cpu_ids; cpu++) {
                is_valid = cpu_port_is_valid(&cpu_port[cpu]);
                if (is_valid && cpu_port_match(&cpu_port[cpu], mpidr)) {
                        cci_port_control(cpu_port[cpu].port, false);
                        return 0;
                }
        }
        return -ENODEV;
}
EXPORT_SYMBOL_GPL(cci_disable_port_by_cpu);

/**
 * cci_enable_port_for_self() - enable a CCI port for calling CPU
 *
 * Enabling a CCI port for the calling CPU implies enabling the CCI
 * port controlling that CPU's cluster. Caller must make sure that the
 * CPU running the code is the first active CPU in the cluster and all
 * other CPUs are quiescent in a low power state  or waiting for this CPU
 * to complete the CCI initialization.
 *
 * Because this is called when the MMU is still off and with no stack,
 * the code must be position independent and ideally rely on callee
 * clobbered registers only.  To achieve this we must code this function
 * entirely in assembler.
 *
 * On success this returns with the proper CCI port enabled.  In case of
 * any failure this never returns as the inability to enable the CCI is
 * fatal and there is no possible recovery at this stage.
 */
asmlinkage void __naked cci_enable_port_for_self(void)
{
        asm volatile ("\n"
"       .arch armv7-a\n"
"       mrc     p15, 0, r0, c0, c0, 5   @ get MPIDR value \n"
"       and     r0, r0, #"__stringify(MPIDR_HWID_BITMASK)" \n"
"       adr     r1, 5f \n"
"       ldr     r2, [r1] \n"
"       add     r1, r1, r2              @ &cpu_port \n"
"       add     ip, r1, %[sizeof_cpu_port] \n"

        /* Loop over the cpu_port array looking for a matching MPIDR */
"1:     ldr     r2, [r1, %[offsetof_cpu_port_mpidr_lsb]] \n"
"       cmp     r2, r0                  @ compare MPIDR \n"
"       bne     2f \n"

        /* Found a match, now test port validity */
"       ldr     r3, [r1, %[offsetof_cpu_port_port]] \n"
"       tst     r3, #"__stringify(PORT_VALID)" \n"
"       bne     3f \n"

        /* no match, loop with the next cpu_port entry */
"2:     add     r1, r1, %[sizeof_struct_cpu_port] \n"
"       cmp     r1, ip                  @ done? \n"
"       blo     1b \n"

        /* CCI port not found -- cheaply try to stall this CPU */
"cci_port_not_found: \n"
"       wfi \n"
"       wfe \n"
"       b       cci_port_not_found \n"

        /* Use matched port index to look up the corresponding ports entry */
"3:     bic     r3, r3, #"__stringify(PORT_VALID)" \n"
"       adr     r0, 6f \n"
"       ldmia   r0, {r1, r2} \n"
"       sub     r1, r1, r0              @ virt - phys \n"
"       ldr     r0, [r0, r2]            @ *(&ports) \n"
"       mov     r2, %[sizeof_struct_ace_port] \n"
"       mla     r0, r2, r3, r0          @ &ports[index] \n"
"       sub     r0, r0, r1              @ virt_to_phys() \n"

        /* Enable the CCI port */
"       ldr     r0, [r0, %[offsetof_port_phys]] \n"
"       mov     r3, %[cci_enable_req]\n"                   
"       str     r3, [r0, #"__stringify(CCI_PORT_CTRL)"] \n"

        /* poll the status reg for completion */
"       adr     r1, 7f \n"
"       ldr     r0, [r1] \n"
"       ldr     r0, [r0, r1]            @ cci_ctrl_base \n"
"4:     ldr     r1, [r0, #"__stringify(CCI_CTRL_STATUS)"] \n"
"       tst     r1, %[cci_control_status_bits] \n"                      
"       bne     4b \n"

"       mov     r0, #0 \n"
"       bx      lr \n"

"       .align  2 \n"
"5:     .word   cpu_port - . \n"
"6:     .word   . \n"
"       .word   ports - 6b \n"
"7:     .word   cci_ctrl_phys - . \n"
        : :
        [sizeof_cpu_port] "i" (sizeof(cpu_port)),
        [cci_enable_req] "i" cpu_to_le32(CCI_ENABLE_REQ),
        [cci_control_status_bits] "i" cpu_to_le32(1),
#ifndef __ARMEB__
        [offsetof_cpu_port_mpidr_lsb] "i" (offsetof(struct cpu_port, mpidr)),
#else
        [offsetof_cpu_port_mpidr_lsb] "i" (offsetof(struct cpu_port, mpidr)+4),
#endif
        [offsetof_cpu_port_port] "i" (offsetof(struct cpu_port, port)),
        [sizeof_struct_cpu_port] "i" (sizeof(struct cpu_port)),
        [sizeof_struct_ace_port] "i" (sizeof(struct cci_ace_port)),
        [offsetof_port_phys] "i" (offsetof(struct cci_ace_port, phys)) );

        unreachable();
}

/**
 * __cci_control_port_by_device() - function to control a CCI port by device
 *                                  reference
 *
 * @dn: device node pointer of the device whose CCI port should be
 *      controlled
 * @enable: if true enables the port, if false disables it
 *
 * Return:
 *      0 on success
 *      -ENODEV on port look-up failure
 */
int notrace __cci_control_port_by_device(struct device_node *dn, bool enable)
{
        int port;

        if (!dn)
                return -ENODEV;

        port = __cci_ace_get_port(dn, ACE_LITE_PORT);
        if (WARN_ONCE(port < 0, "node %s ACE lite port look-up failure\n",
                                dn->full_name))
                return -ENODEV;
        cci_port_control(port, enable);
        return 0;
}
EXPORT_SYMBOL_GPL(__cci_control_port_by_device);

/**
 * __cci_control_port_by_index() - function to control a CCI port by port index
 *
 * @port: port index previously retrieved with cci_ace_get_port()
 * @enable: if true enables the port, if false disables it
 *
 * Return:
 *      0 on success
 *      -ENODEV on port index out of range
 *      -EPERM if operation carried out on an ACE PORT
 */
int notrace __cci_control_port_by_index(u32 port, bool enable)
{
        if (port >= nb_cci_ports || ports[port].type == ACE_INVALID_PORT)
                return -ENODEV;
        /*
         * CCI control for ports connected to CPUS is extremely fragile
         * and must be made to go through a specific and controlled
         * interface (ie cci_disable_port_by_cpu(); control by general purpose
         * indexing is therefore disabled for ACE ports.
         */
        if (ports[port].type == ACE_PORT)
                return -EPERM;

        cci_port_control(port, enable);
        return 0;
}
EXPORT_SYMBOL_GPL(__cci_control_port_by_index);

static const struct cci_nb_ports cci400_ports = {
        .nb_ace = 2,
        .nb_ace_lite = 3
};

static const struct of_device_id arm_cci_matches[] = {
        {.compatible = "arm,cci-400", .data = &cci400_ports },
        {},
};

static const struct of_device_id arm_cci_ctrl_if_matches[] = {
        {.compatible = "arm,cci-400-ctrl-if", },
        {},
};

static int cci_probe(void)
{
        struct cci_nb_ports const *cci_config;
        int ret, i, nb_ace = 0, nb_ace_lite = 0;
        struct device_node *np, *cp;
        struct resource res;
        const char *match_str;
        bool is_ace;

        np = of_find_matching_node(NULL, arm_cci_matches);
        if (!np)
                return -ENODEV;

        if (!of_device_is_available(np))
                return -ENODEV;

        cci_config = of_match_node(arm_cci_matches, np)->data;
        if (!cci_config)
                return -ENODEV;

        nb_cci_ports = cci_config->nb_ace + cci_config->nb_ace_lite;

        ports = kcalloc(nb_cci_ports, sizeof(*ports), GFP_KERNEL);
        if (!ports)
                return -ENOMEM;

        ret = of_address_to_resource(np, 0, &res);
        if (!ret) {
                cci_ctrl_base = ioremap(res.start, resource_size(&res));
                cci_ctrl_phys = res.start;
        }
        if (ret || !cci_ctrl_base) {
                WARN(1, "unable to ioremap CCI ctrl\n");
                ret = -ENXIO;
                goto memalloc_err;
        }

        for_each_child_of_node(np, cp) {
                if (!of_match_node(arm_cci_ctrl_if_matches, cp))
                        continue;

                i = nb_ace + nb_ace_lite;

                if (i >= nb_cci_ports)
                        break;

                if (of_property_read_string(cp, "interface-type",
                                        &match_str)) {
                        WARN(1, "node %s missing interface-type property\n",
                                  cp->full_name);
                        continue;
                }
                is_ace = strcmp(match_str, "ace") == 0;
                if (!is_ace && strcmp(match_str, "ace-lite")) {
                        WARN(1, "node %s containing invalid interface-type property, skipping it\n",
                                        cp->full_name);
                        continue;
                }

                ret = of_address_to_resource(cp, 0, &res);
                if (!ret) {
                        ports[i].base = ioremap(res.start, resource_size(&res));
                        ports[i].phys = res.start;
                }
                if (ret || !ports[i].base) {
                        WARN(1, "unable to ioremap CCI port %d\n", i);
                        continue;
                }

                if (is_ace) {
                        if (WARN_ON(nb_ace >= cci_config->nb_ace))
                                continue;
                        ports[i].type = ACE_PORT;
                        ++nb_ace;
                } else {
                        if (WARN_ON(nb_ace_lite >= cci_config->nb_ace_lite))
                                continue;
                        ports[i].type = ACE_LITE_PORT;
                        ++nb_ace_lite;
                }
                ports[i].dn = cp;
        }

         /* initialize a stashed array of ACE ports to speed-up look-up */
        cci_ace_init_ports();

        /*
         * Multi-cluster systems may need this data when non-coherent, during
         * cluster power-up/power-down. Make sure it reaches main memory.
         */
        sync_cache_w(&cci_ctrl_base);
        sync_cache_w(&cci_ctrl_phys);
        sync_cache_w(&ports);
        sync_cache_w(&cpu_port);
        __sync_cache_range_w(ports, sizeof(*ports) * nb_cci_ports);
        pr_info("ARM CCI driver probed\n");
        return 0;

memalloc_err:

        kfree(ports);
        return ret;
}

static int cci_init_status = -EAGAIN;
static DEFINE_MUTEX(cci_probing);

static int cci_init(void)
{
        if (cci_init_status != -EAGAIN)
                return cci_init_status;

        mutex_lock(&cci_probing);
        if (cci_init_status == -EAGAIN)
                cci_init_status = cci_probe();
        mutex_unlock(&cci_probing);
        return cci_init_status;
}

#ifdef CONFIG_HW_PERF_EVENTS
static struct platform_driver cci_pmu_driver = {
        .driver = {
                   .name = DRIVER_NAME_PMU,
                   .of_match_table = arm_cci_pmu_matches,
                  },
        .probe = cci_pmu_probe,
};

static struct platform_driver cci_platform_driver = {
        .driver = {
                   .name = DRIVER_NAME,
                   .of_match_table = arm_cci_matches,
                  },
        .probe = cci_platform_probe,
};

static int __init cci_platform_init(void)
{
        int ret;

        ret = platform_driver_register(&cci_pmu_driver);
        if (ret)
                return ret;

        return platform_driver_register(&cci_platform_driver);
}

#else

static int __init cci_platform_init(void)
{
        return 0;
}

#endif
/*
 * To sort out early init calls ordering a helper function is provided to
 * check if the CCI driver has beed initialized. Function check if the driver
 * has been initialized, if not it calls the init function that probes
 * the driver and updates the return value.
 */
bool cci_probed(void)
{
        return cci_init() == 0;
}
EXPORT_SYMBOL_GPL(cci_probed);

early_initcall(cci_init);
core_initcall(cci_platform_init);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ARM CCI support");