/*
 * Intel(R) Trace Hub Global Trace Hub
 *
 * Copyright (C) 2014-2015 Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 */

#define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/bitmap.h>

#include "intel_th.h"
#include "gth.h"

struct gth_device;

/**
 * struct gth_output - GTH view on an output port
 * @gth:        backlink to the GTH device
 * @output:     link to output device's output descriptor
 * @index:      output port number
 * @port_type:  one of GTH_* port type values
 * @master:     bitmap of masters configured for this output
 */
struct gth_output {
        struct gth_device       *gth;
        struct intel_th_output  *output;
        unsigned int            index;
        unsigned int            port_type;
        DECLARE_BITMAP(master, TH_CONFIGURABLE_MASTERS + 1);
};

/**
 * struct gth_device - GTH device
 * @dev:        driver core's device
 * @base:       register window base address
 * @output_group:       attributes describing output ports
 * @master_group:       attributes describing master assignments
 * @output:             output ports
 * @master:             master/output port assignments
 * @gth_lock:           serializes accesses to GTH bits
 */
struct gth_device {
        struct device           *dev;
        void __iomem            *base;

        struct attribute_group  output_group;
        struct attribute_group  master_group;
        struct gth_output       output[TH_POSSIBLE_OUTPUTS];
        signed char             master[TH_CONFIGURABLE_MASTERS + 1];
        spinlock_t              gth_lock;
};

static void gth_output_set(struct gth_device *gth, int port,
                           unsigned int config)
{
        unsigned long reg = port & 4 ? REG_GTH_GTHOPT1 : REG_GTH_GTHOPT0;
        u32 val;
        int shift = (port & 3) * 8;

        val = ioread32(gth->base + reg);
        val &= ~(0xff << shift);
        val |= config << shift;
        iowrite32(val, gth->base + reg);
}

static unsigned int gth_output_get(struct gth_device *gth, int port)
{
        unsigned long reg = port & 4 ? REG_GTH_GTHOPT1 : REG_GTH_GTHOPT0;
        u32 val;
        int shift = (port & 3) * 8;

        val = ioread32(gth->base + reg);
        val &= 0xff << shift;
        val >>= shift;

        return val;
}

static void gth_smcfreq_set(struct gth_device *gth, int port,
                            unsigned int freq)
{
        unsigned long reg = REG_GTH_SMCR0 + ((port / 2) * 4);
        int shift = (port & 1) * 16;
        u32 val;

        val = ioread32(gth->base + reg);
        val &= ~(0xffff << shift);
        val |= freq << shift;
        iowrite32(val, gth->base + reg);
}

static unsigned int gth_smcfreq_get(struct gth_device *gth, int port)
{
        unsigned long reg = REG_GTH_SMCR0 + ((port / 2) * 4);
        int shift = (port & 1) * 16;
        u32 val;

        val = ioread32(gth->base + reg);
        val &= 0xffff << shift;
        val >>= shift;

        return val;
}

/*
 * "masters" attribute group
 */

struct master_attribute {
        struct device_attribute attr;
        struct gth_device       *gth;
        unsigned int            master;
};

static void
gth_master_set(struct gth_device *gth, unsigned int master, int port)
{
        unsigned int reg = REG_GTH_SWDEST0 + ((master >> 1) & ~3u);
        unsigned int shift = (master & 0x7) * 4;
        u32 val;

        if (master >= 256) {
                reg = REG_GTH_GSWTDEST;
                shift = 0;
        }

        val = ioread32(gth->base + reg);
        val &= ~(0xf << shift);
        if (port >= 0)
                val |= (0x8 | port) << shift;
        iowrite32(val, gth->base + reg);
}

static ssize_t master_attr_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct master_attribute *ma =
                container_of(attr, struct master_attribute, attr);
        struct gth_device *gth = ma->gth;
        size_t count;
        int port;

        spin_lock(&gth->gth_lock);
        port = gth->master[ma->master];
        spin_unlock(&gth->gth_lock);

        if (port >= 0)
                count = snprintf(buf, PAGE_SIZE, "%x\n", port);
        else
                count = snprintf(buf, PAGE_SIZE, "disabled\n");

        return count;
}

static ssize_t master_attr_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        struct master_attribute *ma =
                container_of(attr, struct master_attribute, attr);
        struct gth_device *gth = ma->gth;
        int old_port, port;

        if (kstrtoint(buf, 10, &port) < 0)
                return -EINVAL;

        if (port >= TH_POSSIBLE_OUTPUTS || port < -1)
                return -EINVAL;

        spin_lock(&gth->gth_lock);

        /* disconnect from the previous output port, if any */
        old_port = gth->master[ma->master];
        if (old_port >= 0) {
                gth->master[ma->master] = -1;
                clear_bit(ma->master, gth->output[old_port].master);
                if (gth->output[old_port].output->active)
                        gth_master_set(gth, ma->master, -1);
        }

        /* connect to the new output port, if any */
        if (port >= 0) {
                /* check if there's a driver for this port */
                if (!gth->output[port].output) {
                        count = -ENODEV;
                        goto unlock;
                }

                set_bit(ma->master, gth->output[port].master);

                /* if the port is active, program this setting */
                if (gth->output[port].output->active)
                        gth_master_set(gth, ma->master, port);
        }

        gth->master[ma->master] = port;

unlock:
        spin_unlock(&gth->gth_lock);

        return count;
}

struct output_attribute {
        struct device_attribute attr;
        struct gth_device       *gth;
        unsigned int            port;
        unsigned int            parm;
};

#define OUTPUT_PARM(_name, _mask, _r, _w, _what)                        \
        [TH_OUTPUT_PARM(_name)] = { .name = __stringify(_name),         \
                                    .get = gth_ ## _what ## _get,       \
                                    .set = gth_ ## _what ## _set,       \
                                    .mask = (_mask),                    \
                                    .readable = (_r),                   \
                                    .writable = (_w) }

static const struct output_parm {
        const char      *name;
        unsigned int    (*get)(struct gth_device *gth, int port);
        void            (*set)(struct gth_device *gth, int port,
                               unsigned int val);
        unsigned int    mask;
        unsigned int    readable : 1,
                        writable : 1;
} output_parms[] = {
        OUTPUT_PARM(port,       0x7,    1, 0, output),
        OUTPUT_PARM(null,       BIT(3), 1, 1, output),
        OUTPUT_PARM(drop,       BIT(4), 1, 1, output),
        OUTPUT_PARM(reset,      BIT(5), 1, 0, output),
        OUTPUT_PARM(flush,      BIT(7), 0, 1, output),
        OUTPUT_PARM(smcfreq,    0xffff, 1, 1, smcfreq),
};

static void
gth_output_parm_set(struct gth_device *gth, int port, unsigned int parm,
                    unsigned int val)
{
        unsigned int config = output_parms[parm].get(gth, port);
        unsigned int mask = output_parms[parm].mask;
        unsigned int shift = __ffs(mask);

        config &= ~mask;
        config |= (val << shift) & mask;
        output_parms[parm].set(gth, port, config);
}

static unsigned int
gth_output_parm_get(struct gth_device *gth, int port, unsigned int parm)
{
        unsigned int config = output_parms[parm].get(gth, port);
        unsigned int mask = output_parms[parm].mask;
        unsigned int shift = __ffs(mask);

        config &= mask;
        config >>= shift;
        return config;
}

/*
 * Reset outputs and sources
 */
static int intel_th_gth_reset(struct gth_device *gth)
{
        u32 scratchpad;
        int port, i;

        scratchpad = ioread32(gth->base + REG_GTH_SCRPD0);
        if (scratchpad & SCRPD_DEBUGGER_IN_USE)
                return -EBUSY;

        /* Always save/restore STH and TU registers in S0ix entry/exit */
        scratchpad |= SCRPD_STH_IS_ENABLED | SCRPD_TRIGGER_IS_ENABLED;
        iowrite32(scratchpad, gth->base + REG_GTH_SCRPD0);

        /* output ports */
        for (port = 0; port < 8; port++) {
                if (gth_output_parm_get(gth, port, TH_OUTPUT_PARM(port)) ==
                    GTH_NONE)
                        continue;

                gth_output_set(gth, port, 0);
                gth_smcfreq_set(gth, port, 16);
        }
        /* disable overrides */
        iowrite32(0, gth->base + REG_GTH_DESTOVR);

        /* masters swdest_0~31 and gswdest */
        for (i = 0; i < 33; i++)
                iowrite32(0, gth->base + REG_GTH_SWDEST0 + i * 4);

        /* sources */
        iowrite32(0, gth->base + REG_GTH_SCR);
        iowrite32(0xfc, gth->base + REG_GTH_SCR2);

        return 0;
}

/*
 * "outputs" attribute group
 */

static ssize_t output_attr_show(struct device *dev,
                                struct device_attribute *attr,
                                char *buf)
{
        struct output_attribute *oa =
                container_of(attr, struct output_attribute, attr);
        struct gth_device *gth = oa->gth;
        size_t count;

        spin_lock(&gth->gth_lock);
        count = snprintf(buf, PAGE_SIZE, "%x\n",
                         gth_output_parm_get(gth, oa->port, oa->parm));
        spin_unlock(&gth->gth_lock);

        return count;
}

static ssize_t output_attr_store(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t count)
{
        struct output_attribute *oa =
                container_of(attr, struct output_attribute, attr);
        struct gth_device *gth = oa->gth;
        unsigned int config;

        if (kstrtouint(buf, 16, &config) < 0)
                return -EINVAL;

        spin_lock(&gth->gth_lock);
        gth_output_parm_set(gth, oa->port, oa->parm, config);
        spin_unlock(&gth->gth_lock);

        return count;
}

static int intel_th_master_attributes(struct gth_device *gth)
{
        struct master_attribute *master_attrs;
        struct attribute **attrs;
        int i, nattrs = TH_CONFIGURABLE_MASTERS + 2;

        attrs = devm_kcalloc(gth->dev, nattrs, sizeof(void *), GFP_KERNEL);
        if (!attrs)
                return -ENOMEM;

        master_attrs = devm_kcalloc(gth->dev, nattrs,
                                    sizeof(struct master_attribute),
                                    GFP_KERNEL);
        if (!master_attrs)
                return -ENOMEM;

        for (i = 0; i < TH_CONFIGURABLE_MASTERS + 1; i++) {
                char *name;

                name = devm_kasprintf(gth->dev, GFP_KERNEL, "%d%s", i,
                                      i == TH_CONFIGURABLE_MASTERS ? "+" : "");
                if (!name)
                        return -ENOMEM;

                master_attrs[i].attr.attr.name = name;
                master_attrs[i].attr.attr.mode = S_IRUGO | S_IWUSR;
                master_attrs[i].attr.show = master_attr_show;
                master_attrs[i].attr.store = master_attr_store;

                sysfs_attr_init(&master_attrs[i].attr.attr);
                attrs[i] = &master_attrs[i].attr.attr;

                master_attrs[i].gth = gth;
                master_attrs[i].master = i;
        }

        gth->master_group.name  = "masters";
        gth->master_group.attrs = attrs;

        return sysfs_create_group(&gth->dev->kobj, &gth->master_group);
}

static int intel_th_output_attributes(struct gth_device *gth)
{
        struct output_attribute *out_attrs;
        struct attribute **attrs;
        int i, j, nouts = TH_POSSIBLE_OUTPUTS;
        int nparms = ARRAY_SIZE(output_parms);
        int nattrs = nouts * nparms + 1;

        attrs = devm_kcalloc(gth->dev, nattrs, sizeof(void *), GFP_KERNEL);
        if (!attrs)
                return -ENOMEM;

        out_attrs = devm_kcalloc(gth->dev, nattrs,
                                 sizeof(struct output_attribute),
                                 GFP_KERNEL);
        if (!out_attrs)
                return -ENOMEM;

        for (i = 0; i < nouts; i++) {
                for (j = 0; j < nparms; j++) {
                        unsigned int idx = i * nparms + j;
                        char *name;

                        name = devm_kasprintf(gth->dev, GFP_KERNEL, "%d_%s", i,
                                              output_parms[j].name);
                        if (!name)
                                return -ENOMEM;

                        out_attrs[idx].attr.attr.name = name;

                        if (output_parms[j].readable) {
                                out_attrs[idx].attr.attr.mode |= S_IRUGO;
                                out_attrs[idx].attr.show = output_attr_show;
                        }

                        if (output_parms[j].writable) {
                                out_attrs[idx].attr.attr.mode |= S_IWUSR;
                                out_attrs[idx].attr.store = output_attr_store;
                        }

                        sysfs_attr_init(&out_attrs[idx].attr.attr);
                        attrs[idx] = &out_attrs[idx].attr.attr;

                        out_attrs[idx].gth = gth;
                        out_attrs[idx].port = i;
                        out_attrs[idx].parm = j;
                }
        }

        gth->output_group.name  = "outputs";
        gth->output_group.attrs = attrs;

        return sysfs_create_group(&gth->dev->kobj, &gth->output_group);
}

/**
 * intel_th_gth_disable() - enable tracing to an output device
 * @thdev:      GTH device
 * @output:     output device's descriptor
 *
 * This will deconfigure all masters set to output to this device,
 * disable tracing using force storeEn off signal and wait for the
 * "pipeline empty" bit for corresponding output port.
 */
static void intel_th_gth_disable(struct intel_th_device *thdev,
                                 struct intel_th_output *output)
{
        struct gth_device *gth = dev_get_drvdata(&thdev->dev);
        unsigned long count;
        int master;
        u32 reg;

        spin_lock(&gth->gth_lock);
        output->active = false;

        for_each_set_bit(master, gth->output[output->port].master,
                         TH_CONFIGURABLE_MASTERS) {
                gth_master_set(gth, master, -1);
        }
        spin_unlock(&gth->gth_lock);

        iowrite32(0, gth->base + REG_GTH_SCR);
        iowrite32(0xfd, gth->base + REG_GTH_SCR2);

        /* wait on pipeline empty for the given port */
        for (reg = 0, count = GTH_PLE_WAITLOOP_DEPTH;
             count && !(reg & BIT(output->port)); count--) {
                reg = ioread32(gth->base + REG_GTH_STAT);
                cpu_relax();
        }

        /* clear force capture done for next captures */
        iowrite32(0xfc, gth->base + REG_GTH_SCR2);

        if (!count)
                dev_dbg(&thdev->dev, "timeout waiting for GTH[%d] PLE\n",
                        output->port);

        reg = ioread32(gth->base + REG_GTH_SCRPD0);
        reg &= ~output->scratchpad;
        iowrite32(reg, gth->base + REG_GTH_SCRPD0);
}

/**
 * intel_th_gth_enable() - enable tracing to an output device
 * @thdev:      GTH device
 * @output:     output device's descriptor
 *
 * This will configure all masters set to output to this device and
 * enable tracing using force storeEn signal.
 */
static void intel_th_gth_enable(struct intel_th_device *thdev,
                                struct intel_th_output *output)
{
        struct gth_device *gth = dev_get_drvdata(&thdev->dev);
        u32 scr = 0xfc0000, scrpd;
        int master;

        spin_lock(&gth->gth_lock);
        for_each_set_bit(master, gth->output[output->port].master,
                         TH_CONFIGURABLE_MASTERS + 1) {
                gth_master_set(gth, master, output->port);
        }

        if (output->multiblock)
                scr |= 0xff;

        output->active = true;
        spin_unlock(&gth->gth_lock);

        scrpd = ioread32(gth->base + REG_GTH_SCRPD0);
        scrpd |= output->scratchpad;
        iowrite32(scrpd, gth->base + REG_GTH_SCRPD0);

        iowrite32(scr, gth->base + REG_GTH_SCR);
        iowrite32(0, gth->base + REG_GTH_SCR2);
}

/**
 * intel_th_gth_assign() - assign output device to a GTH output port
 * @thdev:      GTH device
 * @othdev:     output device
 *
 * This will match a given output device parameters against present
 * output ports on the GTH and fill out relevant bits in output device's
 * descriptor.
 *
 * Return:      0 on success, -errno on error.
 */
static int intel_th_gth_assign(struct intel_th_device *thdev,
                               struct intel_th_device *othdev)
{
        struct gth_device *gth = dev_get_drvdata(&thdev->dev);
        int i, id;

        if (othdev->type != INTEL_TH_OUTPUT)
                return -EINVAL;

        for (i = 0, id = 0; i < TH_POSSIBLE_OUTPUTS; i++) {
                if (gth->output[i].port_type != othdev->output.type)
                        continue;

                if (othdev->id == -1 || othdev->id == id)
                        goto found;

                id++;
        }

        return -ENOENT;

found:
        spin_lock(&gth->gth_lock);
        othdev->output.port = i;
        othdev->output.active = false;
        gth->output[i].output = &othdev->output;
        spin_unlock(&gth->gth_lock);

        return 0;
}

/**
 * intel_th_gth_unassign() - deassociate an output device from its output port
 * @thdev:      GTH device
 * @othdev:     output device
 */
static void intel_th_gth_unassign(struct intel_th_device *thdev,
                                  struct intel_th_device *othdev)
{
        struct gth_device *gth = dev_get_drvdata(&thdev->dev);
        int port = othdev->output.port;

        spin_lock(&gth->gth_lock);
        othdev->output.port = -1;
        othdev->output.active = false;
        gth->output[port].output = NULL;
        spin_unlock(&gth->gth_lock);
}

static int
intel_th_gth_set_output(struct intel_th_device *thdev, unsigned int master)
{
        struct gth_device *gth = dev_get_drvdata(&thdev->dev);
        int port = 0; /* FIXME: make default output configurable */

        /*
         * everything above TH_CONFIGURABLE_MASTERS is controlled by the
         * same register
         */
        if (master > TH_CONFIGURABLE_MASTERS)
                master = TH_CONFIGURABLE_MASTERS;

        spin_lock(&gth->gth_lock);
        if (gth->master[master] == -1) {
                set_bit(master, gth->output[port].master);
                gth->master[master] = port;
        }
        spin_unlock(&gth->gth_lock);

        return 0;
}

static int intel_th_gth_probe(struct intel_th_device *thdev)
{
        struct device *dev = &thdev->dev;
        struct gth_device *gth;
        struct resource *res;
        void __iomem *base;
        int i, ret;

        res = intel_th_device_get_resource(thdev, IORESOURCE_MEM, 0);
        if (!res)
                return -ENODEV;

        base = devm_ioremap(dev, res->start, resource_size(res));
        if (!base)
                return -ENOMEM;

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

        gth->dev = dev;
        gth->base = base;
        spin_lock_init(&gth->gth_lock);

        ret = intel_th_gth_reset(gth);
        if (ret)
                return ret;

        for (i = 0; i < TH_CONFIGURABLE_MASTERS + 1; i++)
                gth->master[i] = -1;

        for (i = 0; i < TH_POSSIBLE_OUTPUTS; i++) {
                gth->output[i].gth = gth;
                gth->output[i].index = i;
                gth->output[i].port_type =
                        gth_output_parm_get(gth, i, TH_OUTPUT_PARM(port));
        }

        if (intel_th_output_attributes(gth) ||
            intel_th_master_attributes(gth)) {
                pr_warn("Can't initialize sysfs attributes\n");

                if (gth->output_group.attrs)
                        sysfs_remove_group(&gth->dev->kobj, &gth->output_group);
                return -ENOMEM;
        }

        dev_set_drvdata(dev, gth);

        return 0;
}

static void intel_th_gth_remove(struct intel_th_device *thdev)
{
        struct gth_device *gth = dev_get_drvdata(&thdev->dev);

        sysfs_remove_group(&gth->dev->kobj, &gth->output_group);
        sysfs_remove_group(&gth->dev->kobj, &gth->master_group);
}

static struct intel_th_driver intel_th_gth_driver = {
        .probe          = intel_th_gth_probe,
        .remove         = intel_th_gth_remove,
        .assign         = intel_th_gth_assign,
        .unassign       = intel_th_gth_unassign,
        .set_output     = intel_th_gth_set_output,
        .enable         = intel_th_gth_enable,
        .disable        = intel_th_gth_disable,
        .driver = {
                .name   = "gth",
                .owner  = THIS_MODULE,
        },
};

module_driver(intel_th_gth_driver,
              intel_th_driver_register,
              intel_th_driver_unregister);

MODULE_ALIAS("intel_th_switch");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Intel(R) Trace Hub Global Trace Hub driver");
MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");