/* Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
 *
 * Description: CoreSight System Trace Macrocell driver
 *
 * 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.
 *
 * Initial implementation by Pratik Patel
 * (C) 2014-2015 Pratik Patel <pratikp@codeaurora.org>
 *
 * Serious refactoring, code cleanup and upgrading to the Coresight upstream
 * framework by Mathieu Poirier
 * (C) 2015-2016 Mathieu Poirier <mathieu.poirier@linaro.org>
 *
 * Guaranteed timing and support for various packet type coming from the
 * generic STM API by Chunyan Zhang
 * (C) 2015-2016 Chunyan Zhang <zhang.chunyan@linaro.org>
 */
#include <asm/local.h>
#include <linux/amba/bus.h>
#include <linux/bitmap.h>
#include <linux/clk.h>
#include <linux/coresight.h>
#include <linux/coresight-stm.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/of_address.h>
#include <linux/perf_event.h>
#include <linux/pm_runtime.h>
#include <linux/stm.h>

#include "coresight-priv.h"

#define STMDMASTARTR                    0xc04
#define STMDMASTOPR                     0xc08
#define STMDMASTATR                     0xc0c
#define STMDMACTLR                      0xc10
#define STMDMAIDR                       0xcfc
#define STMHEER                         0xd00
#define STMHETER                        0xd20
#define STMHEBSR                        0xd60
#define STMHEMCR                        0xd64
#define STMHEMASTR                      0xdf4
#define STMHEFEAT1R                     0xdf8
#define STMHEIDR                        0xdfc
#define STMSPER                         0xe00
#define STMSPTER                        0xe20
#define STMPRIVMASKR                    0xe40
#define STMSPSCR                        0xe60
#define STMSPMSCR                       0xe64
#define STMSPOVERRIDER                  0xe68
#define STMSPMOVERRIDER                 0xe6c
#define STMSPTRIGCSR                    0xe70
#define STMTCSR                         0xe80
#define STMTSSTIMR                      0xe84
#define STMTSFREQR                      0xe8c
#define STMSYNCR                        0xe90
#define STMAUXCR                        0xe94
#define STMSPFEAT1R                     0xea0
#define STMSPFEAT2R                     0xea4
#define STMSPFEAT3R                     0xea8
#define STMITTRIGGER                    0xee8
#define STMITATBDATA0                   0xeec
#define STMITATBCTR2                    0xef0
#define STMITATBID                      0xef4
#define STMITATBCTR0                    0xef8

#define STM_32_CHANNEL                  32
#define BYTES_PER_CHANNEL               256
#define STM_TRACE_BUF_SIZE              4096
#define STM_SW_MASTER_END               127

/* Register bit definition */
#define STMTCSR_BUSY_BIT                23
/* Reserve the first 10 channels for kernel usage */
#define STM_CHANNEL_OFFSET              0

enum stm_pkt_type {
        STM_PKT_TYPE_DATA       = 0x98,
        STM_PKT_TYPE_FLAG       = 0xE8,
        STM_PKT_TYPE_TRIG       = 0xF8,
};

#define stm_channel_addr(drvdata, ch)   (drvdata->chs.base +    \
                                        (ch * BYTES_PER_CHANNEL))
#define stm_channel_off(type, opts)     (type & ~opts)

static int boot_nr_channel;

/*
 * Not really modular but using module_param is the easiest way to
 * remain consistent with existing use cases for now.
 */
module_param_named(
        boot_nr_channel, boot_nr_channel, int, S_IRUGO
);

/**
 * struct channel_space - central management entity for extended ports
 * @base:               memory mapped base address where channels start.
 * @phys:               physical base address of channel region.
 * @guaraneed:          is the channel delivery guaranteed.
 */
struct channel_space {
        void __iomem            *base;
        phys_addr_t             phys;
        unsigned long           *guaranteed;
};

/**
 * struct stm_drvdata - specifics associated to an STM component
 * @base:               memory mapped base address for this component.
 * @dev:                the device entity associated to this component.
 * @atclk:              optional clock for the core parts of the STM.
 * @csdev:              component vitals needed by the framework.
 * @spinlock:           only one at a time pls.
 * @chs:                the channels accociated to this STM.
 * @stm:                structure associated to the generic STM interface.
 * @mode:               this tracer's mode, i.e sysFS, or disabled.
 * @traceid:            value of the current ID for this component.
 * @write_bytes:        Maximus bytes this STM can write at a time.
 * @stmsper:            settings for register STMSPER.
 * @stmspscr:           settings for register STMSPSCR.
 * @numsp:              the total number of stimulus port support by this STM.
 * @stmheer:            settings for register STMHEER.
 * @stmheter:           settings for register STMHETER.
 * @stmhebsr:           settings for register STMHEBSR.
 */
struct stm_drvdata {
        void __iomem            *base;
        struct device           *dev;
        struct clk              *atclk;
        struct coresight_device *csdev;
        spinlock_t              spinlock;
        struct channel_space    chs;
        struct stm_data         stm;
        local_t                 mode;
        u8                      traceid;
        u32                     write_bytes;
        u32                     stmsper;
        u32                     stmspscr;
        u32                     numsp;
        u32                     stmheer;
        u32                     stmheter;
        u32                     stmhebsr;
};

static void stm_hwevent_enable_hw(struct stm_drvdata *drvdata)
{
        CS_UNLOCK(drvdata->base);

        writel_relaxed(drvdata->stmhebsr, drvdata->base + STMHEBSR);
        writel_relaxed(drvdata->stmheter, drvdata->base + STMHETER);
        writel_relaxed(drvdata->stmheer, drvdata->base + STMHEER);
        writel_relaxed(0x01 |   /* Enable HW event tracing */
                       0x04,    /* Error detection on event tracing */
                       drvdata->base + STMHEMCR);

        CS_LOCK(drvdata->base);
}

static void stm_port_enable_hw(struct stm_drvdata *drvdata)
{
        CS_UNLOCK(drvdata->base);
        /* ATB trigger enable on direct writes to TRIG locations */
        writel_relaxed(0x10,
                       drvdata->base + STMSPTRIGCSR);
        writel_relaxed(drvdata->stmspscr, drvdata->base + STMSPSCR);
        writel_relaxed(drvdata->stmsper, drvdata->base + STMSPER);

        CS_LOCK(drvdata->base);
}

static void stm_enable_hw(struct stm_drvdata *drvdata)
{
        if (drvdata->stmheer)
                stm_hwevent_enable_hw(drvdata);

        stm_port_enable_hw(drvdata);

        CS_UNLOCK(drvdata->base);

        /* 4096 byte between synchronisation packets */
        writel_relaxed(0xFFF, drvdata->base + STMSYNCR);
        writel_relaxed((drvdata->traceid << 16 | /* trace id */
                        0x02 |                   /* timestamp enable */
                        0x01),                   /* global STM enable */
                        drvdata->base + STMTCSR);

        CS_LOCK(drvdata->base);
}

static int stm_enable(struct coresight_device *csdev,
                      struct perf_event *event, u32 mode)
{
        u32 val;
        struct stm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

        if (mode != CS_MODE_SYSFS)
                return -EINVAL;

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

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

        pm_runtime_get_sync(drvdata->dev);

        spin_lock(&drvdata->spinlock);
        stm_enable_hw(drvdata);
        spin_unlock(&drvdata->spinlock);

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

static void stm_hwevent_disable_hw(struct stm_drvdata *drvdata)
{
        CS_UNLOCK(drvdata->base);

        writel_relaxed(0x0, drvdata->base + STMHEMCR);
        writel_relaxed(0x0, drvdata->base + STMHEER);
        writel_relaxed(0x0, drvdata->base + STMHETER);

        CS_LOCK(drvdata->base);
}

static void stm_port_disable_hw(struct stm_drvdata *drvdata)
{
        CS_UNLOCK(drvdata->base);

        writel_relaxed(0x0, drvdata->base + STMSPER);
        writel_relaxed(0x0, drvdata->base + STMSPTRIGCSR);

        CS_LOCK(drvdata->base);
}

static void stm_disable_hw(struct stm_drvdata *drvdata)
{
        u32 val;

        CS_UNLOCK(drvdata->base);

        val = readl_relaxed(drvdata->base + STMTCSR);
        val &= ~0x1; /* clear global STM enable [0] */
        writel_relaxed(val, drvdata->base + STMTCSR);

        CS_LOCK(drvdata->base);

        stm_port_disable_hw(drvdata);
        if (drvdata->stmheer)
                stm_hwevent_disable_hw(drvdata);
}

static void stm_disable(struct coresight_device *csdev,
                        struct perf_event *event)
{
        struct stm_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.
         */
        if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
                spin_lock(&drvdata->spinlock);
                stm_disable_hw(drvdata);
                spin_unlock(&drvdata->spinlock);

                /* Wait until the engine has completely stopped */
                coresight_timeout(drvdata, STMTCSR, STMTCSR_BUSY_BIT, 0);

                pm_runtime_put(drvdata->dev);

                local_set(&drvdata->mode, CS_MODE_DISABLED);
                dev_info(drvdata->dev, "STM tracing disabled\n");
        }
}

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

        return drvdata->traceid;
}

static const struct coresight_ops_source stm_source_ops = {
        .trace_id       = stm_trace_id,
        .enable         = stm_enable,
        .disable        = stm_disable,
};

static const struct coresight_ops stm_cs_ops = {
        .source_ops     = &stm_source_ops,
};

static inline bool stm_addr_unaligned(const void *addr, u8 write_bytes)
{
        return ((unsigned long)addr & (write_bytes - 1));
}

static void stm_send(void *addr, const void *data, u32 size, u8 write_bytes)
{
        u8 paload[8];

        if (stm_addr_unaligned(data, write_bytes)) {
                memcpy(paload, data, size);
                data = paload;
        }

        /* now we are 64bit/32bit aligned */
        switch (size) {
#ifdef CONFIG_64BIT
        case 8:
                writeq_relaxed(*(u64 *)data, addr);
                break;
#endif
        case 4:
                writel_relaxed(*(u32 *)data, addr);
                break;
        case 2:
                writew_relaxed(*(u16 *)data, addr);
                break;
        case 1:
                writeb_relaxed(*(u8 *)data, addr);
                break;
        default:
                break;
        }
}

static int stm_generic_link(struct stm_data *stm_data,
                            unsigned int master,  unsigned int channel)
{
        struct stm_drvdata *drvdata = container_of(stm_data,
                                                   struct stm_drvdata, stm);
        if (!drvdata || !drvdata->csdev)
                return -EINVAL;

        return coresight_enable(drvdata->csdev);
}

static void stm_generic_unlink(struct stm_data *stm_data,
                               unsigned int master,  unsigned int channel)
{
        struct stm_drvdata *drvdata = container_of(stm_data,
                                                   struct stm_drvdata, stm);
        if (!drvdata || !drvdata->csdev)
                return;

        coresight_disable(drvdata->csdev);
}

static phys_addr_t
stm_mmio_addr(struct stm_data *stm_data, unsigned int master,
              unsigned int channel, unsigned int nr_chans)
{
        struct stm_drvdata *drvdata = container_of(stm_data,
                                                   struct stm_drvdata, stm);
        phys_addr_t addr;

        addr = drvdata->chs.phys + channel * BYTES_PER_CHANNEL;

        if (offset_in_page(addr) ||
            offset_in_page(nr_chans * BYTES_PER_CHANNEL))
                return 0;

        return addr;
}

static long stm_generic_set_options(struct stm_data *stm_data,
                                    unsigned int master,
                                    unsigned int channel,
                                    unsigned int nr_chans,
                                    unsigned long options)
{
        struct stm_drvdata *drvdata = container_of(stm_data,
                                                   struct stm_drvdata, stm);
        if (!(drvdata && local_read(&drvdata->mode)))
                return -EINVAL;

        if (channel >= drvdata->numsp)
                return -EINVAL;

        switch (options) {
        case STM_OPTION_GUARANTEED:
                set_bit(channel, drvdata->chs.guaranteed);
                break;

        case STM_OPTION_INVARIANT:
                clear_bit(channel, drvdata->chs.guaranteed);
                break;

        default:
                return -EINVAL;
        }

        return 0;
}

static ssize_t notrace stm_generic_packet(struct stm_data *stm_data,
                                  unsigned int master,
                                  unsigned int channel,
                                  unsigned int packet,
                                  unsigned int flags,
                                  unsigned int size,
                                  const unsigned char *payload)
{
        unsigned long ch_addr;
        struct stm_drvdata *drvdata = container_of(stm_data,
                                                   struct stm_drvdata, stm);

        if (!(drvdata && local_read(&drvdata->mode)))
                return -EACCES;

        if (channel >= drvdata->numsp)
                return -EINVAL;

        ch_addr = (unsigned long)stm_channel_addr(drvdata, channel);

        flags = (flags == STP_PACKET_TIMESTAMPED) ? STM_FLAG_TIMESTAMPED : 0;
        flags |= test_bit(channel, drvdata->chs.guaranteed) ?
                           STM_FLAG_GUARANTEED : 0;

        if (size > drvdata->write_bytes)
                size = drvdata->write_bytes;
        else
                size = rounddown_pow_of_two(size);

        switch (packet) {
        case STP_PACKET_FLAG:
                ch_addr |= stm_channel_off(STM_PKT_TYPE_FLAG, flags);

                /*
                 * The generic STM core sets a size of '0' on flag packets.
                 * As such send a flag packet of size '1' and tell the
                 * core we did so.
                 */
                stm_send((void *)ch_addr, payload, 1, drvdata->write_bytes);
                size = 1;
                break;

        case STP_PACKET_DATA:
                ch_addr |= stm_channel_off(STM_PKT_TYPE_DATA, flags);
                stm_send((void *)ch_addr, payload, size,
                                drvdata->write_bytes);
                break;

        default:
                return -ENOTSUPP;
        }

        return size;
}

static ssize_t hwevent_enable_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val = drvdata->stmheer;

        return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
}

static ssize_t hwevent_enable_store(struct device *dev,
                                    struct device_attribute *attr,
                                    const char *buf, size_t size)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val;
        int ret = 0;

        ret = kstrtoul(buf, 16, &val);
        if (ret)
                return -EINVAL;

        drvdata->stmheer = val;
        /* HW event enable and trigger go hand in hand */
        drvdata->stmheter = val;

        return size;
}
static DEVICE_ATTR_RW(hwevent_enable);

static ssize_t hwevent_select_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val = drvdata->stmhebsr;

        return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
}

static ssize_t hwevent_select_store(struct device *dev,
                                    struct device_attribute *attr,
                                    const char *buf, size_t size)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val;
        int ret = 0;

        ret = kstrtoul(buf, 16, &val);
        if (ret)
                return -EINVAL;

        drvdata->stmhebsr = val;

        return size;
}
static DEVICE_ATTR_RW(hwevent_select);

static ssize_t port_select_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val;

        if (!local_read(&drvdata->mode)) {
                val = drvdata->stmspscr;
        } else {
                spin_lock(&drvdata->spinlock);
                val = readl_relaxed(drvdata->base + STMSPSCR);
                spin_unlock(&drvdata->spinlock);
        }

        return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
}

static ssize_t port_select_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t size)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val, stmsper;
        int ret = 0;

        ret = kstrtoul(buf, 16, &val);
        if (ret)
                return ret;

        spin_lock(&drvdata->spinlock);
        drvdata->stmspscr = val;

        if (local_read(&drvdata->mode)) {
                CS_UNLOCK(drvdata->base);
                /* Process as per ARM's TRM recommendation */
                stmsper = readl_relaxed(drvdata->base + STMSPER);
                writel_relaxed(0x0, drvdata->base + STMSPER);
                writel_relaxed(drvdata->stmspscr, drvdata->base + STMSPSCR);
                writel_relaxed(stmsper, drvdata->base + STMSPER);
                CS_LOCK(drvdata->base);
        }
        spin_unlock(&drvdata->spinlock);

        return size;
}
static DEVICE_ATTR_RW(port_select);

static ssize_t port_enable_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val;

        if (!local_read(&drvdata->mode)) {
                val = drvdata->stmsper;
        } else {
                spin_lock(&drvdata->spinlock);
                val = readl_relaxed(drvdata->base + STMSPER);
                spin_unlock(&drvdata->spinlock);
        }

        return scnprintf(buf, PAGE_SIZE, "%#lx\n", val);
}

static ssize_t port_enable_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t size)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
        unsigned long val;
        int ret = 0;

        ret = kstrtoul(buf, 16, &val);
        if (ret)
                return ret;

        spin_lock(&drvdata->spinlock);
        drvdata->stmsper = val;

        if (local_read(&drvdata->mode)) {
                CS_UNLOCK(drvdata->base);
                writel_relaxed(drvdata->stmsper, drvdata->base + STMSPER);
                CS_LOCK(drvdata->base);
        }
        spin_unlock(&drvdata->spinlock);

        return size;
}
static DEVICE_ATTR_RW(port_enable);

static ssize_t traceid_show(struct device *dev,
                            struct device_attribute *attr, char *buf)
{
        unsigned long val;
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);

        val = drvdata->traceid;
        return sprintf(buf, "%#lx\n", val);
}

static ssize_t traceid_store(struct device *dev,
                             struct device_attribute *attr,
                             const char *buf, size_t size)
{
        int ret;
        unsigned long val;
        struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);

        ret = kstrtoul(buf, 16, &val);
        if (ret)
                return ret;

        /* traceid field is 7bit wide on STM32 */
        drvdata->traceid = val & 0x7f;
        return size;
}
static DEVICE_ATTR_RW(traceid);

#define coresight_stm_simple_func(name, offset) \
        coresight_simple_func(struct stm_drvdata, NULL, name, offset)

coresight_stm_simple_func(tcsr, STMTCSR);
coresight_stm_simple_func(tsfreqr, STMTSFREQR);
coresight_stm_simple_func(syncr, STMSYNCR);
coresight_stm_simple_func(sper, STMSPER);
coresight_stm_simple_func(spter, STMSPTER);
coresight_stm_simple_func(privmaskr, STMPRIVMASKR);
coresight_stm_simple_func(spscr, STMSPSCR);
coresight_stm_simple_func(spmscr, STMSPMSCR);
coresight_stm_simple_func(spfeat1r, STMSPFEAT1R);
coresight_stm_simple_func(spfeat2r, STMSPFEAT2R);
coresight_stm_simple_func(spfeat3r, STMSPFEAT3R);
coresight_stm_simple_func(devid, CORESIGHT_DEVID);

static struct attribute *coresight_stm_attrs[] = {
        &dev_attr_hwevent_enable.attr,
        &dev_attr_hwevent_select.attr,
        &dev_attr_port_enable.attr,
        &dev_attr_port_select.attr,
        &dev_attr_traceid.attr,
        NULL,
};

static struct attribute *coresight_stm_mgmt_attrs[] = {
        &dev_attr_tcsr.attr,
        &dev_attr_tsfreqr.attr,
        &dev_attr_syncr.attr,
        &dev_attr_sper.attr,
        &dev_attr_spter.attr,
        &dev_attr_privmaskr.attr,
        &dev_attr_spscr.attr,
        &dev_attr_spmscr.attr,
        &dev_attr_spfeat1r.attr,
        &dev_attr_spfeat2r.attr,
        &dev_attr_spfeat3r.attr,
        &dev_attr_devid.attr,
        NULL,
};

static const struct attribute_group coresight_stm_group = {
        .attrs = coresight_stm_attrs,
};

static const struct attribute_group coresight_stm_mgmt_group = {
        .attrs = coresight_stm_mgmt_attrs,
        .name = "mgmt",
};

static const struct attribute_group *coresight_stm_groups[] = {
        &coresight_stm_group,
        &coresight_stm_mgmt_group,
        NULL,
};

static int stm_get_resource_byname(struct device_node *np,
                                   char *ch_base, struct resource *res)
{
        const char *name = NULL;
        int index = 0, found = 0;

        while (!of_property_read_string_index(np, "reg-names", index, &name)) {
                if (strcmp(ch_base, name)) {
                        index++;
                        continue;
                }

                /* We have a match and @index is where it's at */
                found = 1;
                break;
        }

        if (!found)
                return -EINVAL;

        return of_address_to_resource(np, index, res);
}

static u32 stm_fundamental_data_size(struct stm_drvdata *drvdata)
{
        u32 stmspfeat2r;

        if (!IS_ENABLED(CONFIG_64BIT))
                return 4;

        stmspfeat2r = readl_relaxed(drvdata->base + STMSPFEAT2R);

        /*
         * bit[15:12] represents the fundamental data size
         * 0 - 32-bit data
         * 1 - 64-bit data
         */
        return BMVAL(stmspfeat2r, 12, 15) ? 8 : 4;
}

static u32 stm_num_stimulus_port(struct stm_drvdata *drvdata)
{
        u32 numsp;

        numsp = readl_relaxed(drvdata->base + CORESIGHT_DEVID);
        /*
         * NUMPS in STMDEVID is 17 bit long and if equal to 0x0,
         * 32 stimulus ports are supported.
         */
        numsp &= 0x1ffff;
        if (!numsp)
                numsp = STM_32_CHANNEL;
        return numsp;
}

static void stm_init_default_data(struct stm_drvdata *drvdata)
{
        /* Don't use port selection */
        drvdata->stmspscr = 0x0;
        /*
         * Enable all channel regardless of their number.  When port
         * selection isn't used (see above) STMSPER applies to all
         * 32 channel group available, hence setting all 32 bits to 1
         */
        drvdata->stmsper = ~0x0;

        /*
         * The trace ID value for *ETM* tracers start at CPU_ID * 2 + 0x10 and
         * anything equal to or higher than 0x70 is reserved.  Since 0x00 is
         * also reserved the STM trace ID needs to be higher than 0x00 and
         * lowner than 0x10.
         */
        drvdata->traceid = 0x1;

        /* Set invariant transaction timing on all channels */
        bitmap_clear(drvdata->chs.guaranteed, 0, drvdata->numsp);
}

static void stm_init_generic_data(struct stm_drvdata *drvdata)
{
        drvdata->stm.name = dev_name(drvdata->dev);

        /*
         * MasterIDs are assigned at HW design phase. As such the core is
         * using a single master for interaction with this device.
         */
        drvdata->stm.sw_start = 1;
        drvdata->stm.sw_end = 1;
        drvdata->stm.hw_override = true;
        drvdata->stm.sw_nchannels = drvdata->numsp;
        drvdata->stm.sw_mmiosz = BYTES_PER_CHANNEL;
        drvdata->stm.packet = stm_generic_packet;
        drvdata->stm.mmio_addr = stm_mmio_addr;
        drvdata->stm.link = stm_generic_link;
        drvdata->stm.unlink = stm_generic_unlink;
        drvdata->stm.set_options = stm_generic_set_options;
}

static int stm_probe(struct amba_device *adev, const struct amba_id *id)
{
        int ret;
        void __iomem *base;
        unsigned long *guaranteed;
        struct device *dev = &adev->dev;
        struct coresight_platform_data *pdata = NULL;
        struct stm_drvdata *drvdata;
        struct resource *res = &adev->res;
        struct resource ch_res;
        size_t res_size, bitmap_size;
        struct coresight_desc desc = { 0 };
        struct device_node *np = adev->dev.of_node;

        if (np) {
                pdata = of_get_coresight_platform_data(dev, np);
                if (IS_ERR(pdata))
                        return PTR_ERR(pdata);
                adev->dev.platform_data = pdata;
        }
        drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
        if (!drvdata)
                return -ENOMEM;

        drvdata->dev = &adev->dev;
        drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
        if (!IS_ERR(drvdata->atclk)) {
                ret = clk_prepare_enable(drvdata->atclk);
                if (ret)
                        return ret;
        }
        dev_set_drvdata(dev, drvdata);

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

        ret = stm_get_resource_byname(np, "stm-stimulus-base", &ch_res);
        if (ret)
                return ret;
        drvdata->chs.phys = ch_res.start;

        base = devm_ioremap_resource(dev, &ch_res);
        if (IS_ERR(base))
                return PTR_ERR(base);
        drvdata->chs.base = base;

        drvdata->write_bytes = stm_fundamental_data_size(drvdata);

        if (boot_nr_channel) {
                drvdata->numsp = boot_nr_channel;
                res_size = min((resource_size_t)(boot_nr_channel *
                                  BYTES_PER_CHANNEL), resource_size(res));
        } else {
                drvdata->numsp = stm_num_stimulus_port(drvdata);
                res_size = min((resource_size_t)(drvdata->numsp *
                                 BYTES_PER_CHANNEL), resource_size(res));
        }
        bitmap_size = BITS_TO_LONGS(drvdata->numsp) * sizeof(long);

        guaranteed = devm_kzalloc(dev, bitmap_size, GFP_KERNEL);
        if (!guaranteed)
                return -ENOMEM;
        drvdata->chs.guaranteed = guaranteed;

        spin_lock_init(&drvdata->spinlock);

        stm_init_default_data(drvdata);
        stm_init_generic_data(drvdata);

        if (stm_register_device(dev, &drvdata->stm, THIS_MODULE)) {
                dev_info(dev,
                         "stm_register_device failed, probing deffered\n");
                return -EPROBE_DEFER;
        }

        desc.type = CORESIGHT_DEV_TYPE_SOURCE;
        desc.subtype.source_subtype = CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE;
        desc.ops = &stm_cs_ops;
        desc.pdata = pdata;
        desc.dev = dev;
        desc.groups = coresight_stm_groups;
        drvdata->csdev = coresight_register(&desc);
        if (IS_ERR(drvdata->csdev)) {
                ret = PTR_ERR(drvdata->csdev);
                goto stm_unregister;
        }

        pm_runtime_put(&adev->dev);

        dev_info(dev, "%s initialized\n", (char *)id->data);
        return 0;

stm_unregister:
        stm_unregister_device(&drvdata->stm);
        return ret;
}

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

        if (drvdata && !IS_ERR(drvdata->atclk))
                clk_disable_unprepare(drvdata->atclk);

        return 0;
}

static int stm_runtime_resume(struct device *dev)
{
        struct stm_drvdata *drvdata = dev_get_drvdata(dev);

        if (drvdata && !IS_ERR(drvdata->atclk))
                clk_prepare_enable(drvdata->atclk);

        return 0;
}
#endif

static const struct dev_pm_ops stm_dev_pm_ops = {
        SET_RUNTIME_PM_OPS(stm_runtime_suspend, stm_runtime_resume, NULL)
};

static struct amba_id stm_ids[] = {
        {
                .id     = 0x0003b962,
                .mask   = 0x0003ffff,
                .data   = "STM32",
        },
        {
                .id     = 0x0003b963,
                .mask   = 0x0003ffff,
                .data   = "STM500",
        },
        { 0, 0},
};

static struct amba_driver stm_driver = {
        .drv = {
                .name   = "coresight-stm",
                .owner  = THIS_MODULE,
                .pm     = &stm_dev_pm_ops,
                .suppress_bind_attrs = true,
        },
        .probe          = stm_probe,
        .id_table       = stm_ids,
};

builtin_amba_driver(stm_driver);