/*
 * Greybus interface code
 *
 * Copyright 2014 Google Inc.
 * Copyright 2014 Linaro Ltd.
 *
 * Released under the GPLv2 only.
 */

#include <linux/delay.h>

#include "greybus.h"
#include "greybus_trace.h"

#define GB_INTERFACE_MODE_SWITCH_TIMEOUT        2000

#define GB_INTERFACE_DEVICE_ID_BAD      0xff

#define GB_INTERFACE_AUTOSUSPEND_MS                     3000

/* Time required for interface to enter standby before disabling REFCLK */
#define GB_INTERFACE_SUSPEND_HIBERNATE_DELAY_MS                 20

/* Don't-care selector index */
#define DME_SELECTOR_INDEX_NULL         0

/* DME attributes */
/* FIXME: remove ES2 support and DME_T_TST_SRC_INCREMENT */
#define DME_T_TST_SRC_INCREMENT         0x4083

#define DME_DDBL1_MANUFACTURERID        0x5003
#define DME_DDBL1_PRODUCTID             0x5004

#define DME_TOSHIBA_GMP_VID             0x6000
#define DME_TOSHIBA_GMP_PID             0x6001
#define DME_TOSHIBA_GMP_SN0             0x6002
#define DME_TOSHIBA_GMP_SN1             0x6003
#define DME_TOSHIBA_GMP_INIT_STATUS     0x6101

/* DDBL1 Manufacturer and Product ids */
#define TOSHIBA_DMID                    0x0126
#define TOSHIBA_ES2_BRIDGE_DPID         0x1000
#define TOSHIBA_ES3_APBRIDGE_DPID       0x1001
#define TOSHIBA_ES3_GBPHY_DPID  0x1002

static int gb_interface_hibernate_link(struct gb_interface *intf);
static int gb_interface_refclk_set(struct gb_interface *intf, bool enable);

static int gb_interface_dme_attr_get(struct gb_interface *intf,
                                                        u16 attr, u32 *val)
{
        return gb_svc_dme_peer_get(intf->hd->svc, intf->interface_id,
                                        attr, DME_SELECTOR_INDEX_NULL, val);
}

static int gb_interface_read_ara_dme(struct gb_interface *intf)
{
        u32 sn0, sn1;
        int ret;

        /*
         * Unless this is a Toshiba bridge, bail out until we have defined
         * standard GMP attributes.
         */
        if (intf->ddbl1_manufacturer_id != TOSHIBA_DMID) {
                dev_err(&intf->dev, "unknown manufacturer %08x\n",
                                intf->ddbl1_manufacturer_id);
                return -ENODEV;
        }

        ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_VID,
                                        &intf->vendor_id);
        if (ret)
                return ret;

        ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_PID,
                                        &intf->product_id);
        if (ret)
                return ret;

        ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_SN0, &sn0);
        if (ret)
                return ret;

        ret = gb_interface_dme_attr_get(intf, DME_TOSHIBA_GMP_SN1, &sn1);
        if (ret)
                return ret;

        intf->serial_number = (u64)sn1 << 32 | sn0;

        return 0;
}

static int gb_interface_read_dme(struct gb_interface *intf)
{
        int ret;

        /* DME attributes have already been read */
        if (intf->dme_read)
                return 0;

        ret = gb_interface_dme_attr_get(intf, DME_DDBL1_MANUFACTURERID,
                                        &intf->ddbl1_manufacturer_id);
        if (ret)
                return ret;

        ret = gb_interface_dme_attr_get(intf, DME_DDBL1_PRODUCTID,
                                        &intf->ddbl1_product_id);
        if (ret)
                return ret;

        if (intf->ddbl1_manufacturer_id == TOSHIBA_DMID &&
                        intf->ddbl1_product_id == TOSHIBA_ES2_BRIDGE_DPID) {
                intf->quirks |= GB_INTERFACE_QUIRK_NO_GMP_IDS;
                intf->quirks |= GB_INTERFACE_QUIRK_NO_INIT_STATUS;
        }

        ret = gb_interface_read_ara_dme(intf);
        if (ret)
                return ret;

        intf->dme_read = true;

        return 0;
}

static int gb_interface_route_create(struct gb_interface *intf)
{
        struct gb_svc *svc = intf->hd->svc;
        u8 intf_id = intf->interface_id;
        u8 device_id;
        int ret;

        /* Allocate an interface device id. */
        ret = ida_simple_get(&svc->device_id_map,
                             GB_SVC_DEVICE_ID_MIN, GB_SVC_DEVICE_ID_MAX + 1,
                             GFP_KERNEL);
        if (ret < 0) {
                dev_err(&intf->dev, "failed to allocate device id: %d\n", ret);
                return ret;
        }
        device_id = ret;

        ret = gb_svc_intf_device_id(svc, intf_id, device_id);
        if (ret) {
                dev_err(&intf->dev, "failed to set device id %u: %d\n",
                                device_id, ret);
                goto err_ida_remove;
        }

        /* FIXME: Hard-coded AP device id. */
        ret = gb_svc_route_create(svc, svc->ap_intf_id, GB_SVC_DEVICE_ID_AP,
                                  intf_id, device_id);
        if (ret) {
                dev_err(&intf->dev, "failed to create route: %d\n", ret);
                goto err_svc_id_free;
        }

        intf->device_id = device_id;

        return 0;

err_svc_id_free:
        /*
         * XXX Should we tell SVC that this id doesn't belong to interface
         * XXX anymore.
         */
err_ida_remove:
        ida_simple_remove(&svc->device_id_map, device_id);

        return ret;
}

static void gb_interface_route_destroy(struct gb_interface *intf)
{
        struct gb_svc *svc = intf->hd->svc;

        if (intf->device_id == GB_INTERFACE_DEVICE_ID_BAD)
                return;

        gb_svc_route_destroy(svc, svc->ap_intf_id, intf->interface_id);
        ida_simple_remove(&svc->device_id_map, intf->device_id);
        intf->device_id = GB_INTERFACE_DEVICE_ID_BAD;
}

/* Locking: Caller holds the interface mutex. */
static int gb_interface_legacy_mode_switch(struct gb_interface *intf)
{
        int ret;

        dev_info(&intf->dev, "legacy mode switch detected\n");

        /* Mark as disconnected to prevent I/O during disable. */
        intf->disconnected = true;
        gb_interface_disable(intf);
        intf->disconnected = false;

        ret = gb_interface_enable(intf);
        if (ret) {
                dev_err(&intf->dev, "failed to re-enable interface: %d\n", ret);
                gb_interface_deactivate(intf);
        }

        return ret;
}

void gb_interface_mailbox_event(struct gb_interface *intf, u16 result,
                                                                u32 mailbox)
{
        mutex_lock(&intf->mutex);

        if (result) {
                dev_warn(&intf->dev,
                                "mailbox event with UniPro error: 0x%04x\n",
                                result);
                goto err_disable;
        }

        if (mailbox != GB_SVC_INTF_MAILBOX_GREYBUS) {
                dev_warn(&intf->dev,
                                "mailbox event with unexpected value: 0x%08x\n",
                                mailbox);
                goto err_disable;
        }

        if (intf->quirks & GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH) {
                gb_interface_legacy_mode_switch(intf);
                goto out_unlock;
        }

        if (!intf->mode_switch) {
                dev_warn(&intf->dev, "unexpected mailbox event: 0x%08x\n",
                                mailbox);
                goto err_disable;
        }

        dev_info(&intf->dev, "mode switch detected\n");

        complete(&intf->mode_switch_completion);

out_unlock:
        mutex_unlock(&intf->mutex);

        return;

err_disable:
        gb_interface_disable(intf);
        gb_interface_deactivate(intf);
        mutex_unlock(&intf->mutex);
}

static void gb_interface_mode_switch_work(struct work_struct *work)
{
        struct gb_interface *intf;
        struct gb_control *control;
        unsigned long timeout;
        int ret;

        intf = container_of(work, struct gb_interface, mode_switch_work);

        mutex_lock(&intf->mutex);
        /* Make sure interface is still enabled. */
        if (!intf->enabled) {
                dev_dbg(&intf->dev, "mode switch aborted\n");
                intf->mode_switch = false;
                mutex_unlock(&intf->mutex);
                goto out_interface_put;
        }

        /*
         * Prepare the control device for mode switch and make sure to get an
         * extra reference before it goes away during interface disable.
         */
        control = gb_control_get(intf->control);
        gb_control_mode_switch_prepare(control);
        gb_interface_disable(intf);
        mutex_unlock(&intf->mutex);

        timeout = msecs_to_jiffies(GB_INTERFACE_MODE_SWITCH_TIMEOUT);
        ret = wait_for_completion_interruptible_timeout(
                        &intf->mode_switch_completion, timeout);

        /* Finalise control-connection mode switch. */
        gb_control_mode_switch_complete(control);
        gb_control_put(control);

        if (ret < 0) {
                dev_err(&intf->dev, "mode switch interrupted\n");
                goto err_deactivate;
        } else if (ret == 0) {
                dev_err(&intf->dev, "mode switch timed out\n");
                goto err_deactivate;
        }

        /* Re-enable (re-enumerate) interface if still active. */
        mutex_lock(&intf->mutex);
        intf->mode_switch = false;
        if (intf->active) {
                ret = gb_interface_enable(intf);
                if (ret) {
                        dev_err(&intf->dev, "failed to re-enable interface: %d\n",
                                        ret);
                        gb_interface_deactivate(intf);
                }
        }
        mutex_unlock(&intf->mutex);

out_interface_put:
        gb_interface_put(intf);

        return;

err_deactivate:
        mutex_lock(&intf->mutex);
        intf->mode_switch = false;
        gb_interface_deactivate(intf);
        mutex_unlock(&intf->mutex);

        gb_interface_put(intf);
}

int gb_interface_request_mode_switch(struct gb_interface *intf)
{
        int ret = 0;

        mutex_lock(&intf->mutex);
        if (intf->mode_switch) {
                ret = -EBUSY;
                goto out_unlock;
        }

        intf->mode_switch = true;
        reinit_completion(&intf->mode_switch_completion);

        /*
         * Get a reference to the interface device, which will be put once the
         * mode switch is complete.
         */
        get_device(&intf->dev);

        if (!queue_work(system_long_wq, &intf->mode_switch_work)) {
                put_device(&intf->dev);
                ret = -EBUSY;
                goto out_unlock;
        }

out_unlock:
        mutex_unlock(&intf->mutex);

        return ret;
}
EXPORT_SYMBOL_GPL(gb_interface_request_mode_switch);

/*
 * T_TstSrcIncrement is written by the module on ES2 as a stand-in for the
 * init-status attribute DME_TOSHIBA_INIT_STATUS. The AP needs to read and
 * clear it after reading a non-zero value from it.
 *
 * FIXME: This is module-hardware dependent and needs to be extended for every
 * type of module we want to support.
 */
static int gb_interface_read_and_clear_init_status(struct gb_interface *intf)
{
        struct gb_host_device *hd = intf->hd;
        unsigned long bootrom_quirks;
        unsigned long s2l_quirks;
        int ret;
        u32 value;
        u16 attr;
        u8 init_status;

        /*
         * ES2 bridges use T_TstSrcIncrement for the init status.
         *
         * FIXME: Remove ES2 support
         */
        if (intf->quirks & GB_INTERFACE_QUIRK_NO_INIT_STATUS)
                attr = DME_T_TST_SRC_INCREMENT;
        else
                attr = DME_TOSHIBA_GMP_INIT_STATUS;

        ret = gb_svc_dme_peer_get(hd->svc, intf->interface_id, attr,
                                  DME_SELECTOR_INDEX_NULL, &value);
        if (ret)
                return ret;

        /*
         * A nonzero init status indicates the module has finished
         * initializing.
         */
        if (!value) {
                dev_err(&intf->dev, "invalid init status\n");
                return -ENODEV;
        }

        /*
         * Extract the init status.
         *
         * For ES2: We need to check lowest 8 bits of 'value'.
         * For ES3: We need to check highest 8 bits out of 32 of 'value'.
         *
         * FIXME: Remove ES2 support
         */
        if (intf->quirks & GB_INTERFACE_QUIRK_NO_INIT_STATUS)
                init_status = value & 0xff;
        else
                init_status = value >> 24;

        /*
         * Check if the interface is executing the quirky ES3 bootrom that,
         * for example, requires E2EFC, CSD and CSV to be disabled.
         */
        bootrom_quirks = GB_INTERFACE_QUIRK_NO_CPORT_FEATURES |
                                GB_INTERFACE_QUIRK_FORCED_DISABLE |
                                GB_INTERFACE_QUIRK_LEGACY_MODE_SWITCH |
                                GB_INTERFACE_QUIRK_NO_BUNDLE_ACTIVATE;

        s2l_quirks = GB_INTERFACE_QUIRK_NO_PM;

        switch (init_status) {
        case GB_INIT_BOOTROM_UNIPRO_BOOT_STARTED:
        case GB_INIT_BOOTROM_FALLBACK_UNIPRO_BOOT_STARTED:
                intf->quirks |= bootrom_quirks;
                break;
        case GB_INIT_S2_LOADER_BOOT_STARTED:
                /* S2 Loader doesn't support runtime PM */
                intf->quirks &= ~bootrom_quirks;
                intf->quirks |= s2l_quirks;
                break;
        default:
                intf->quirks &= ~bootrom_quirks;
                intf->quirks &= ~s2l_quirks;
        }

        /* Clear the init status. */
        return gb_svc_dme_peer_set(hd->svc, intf->interface_id, attr,
                                   DME_SELECTOR_INDEX_NULL, 0);
}

/* interface sysfs attributes */
#define gb_interface_attr(field, type)                                  \
static ssize_t field##_show(struct device *dev,                         \
                            struct device_attribute *attr,              \
                            char *buf)                                  \
{                                                                       \
        struct gb_interface *intf = to_gb_interface(dev);               \
        return scnprintf(buf, PAGE_SIZE, type"\n", intf->field);        \
}                                                                       \
static DEVICE_ATTR_RO(field)

gb_interface_attr(ddbl1_manufacturer_id, "0x%08x");
gb_interface_attr(ddbl1_product_id, "0x%08x");
gb_interface_attr(interface_id, "%u");
gb_interface_attr(vendor_id, "0x%08x");
gb_interface_attr(product_id, "0x%08x");
gb_interface_attr(serial_number, "0x%016llx");

static ssize_t voltage_now_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct gb_interface *intf = to_gb_interface(dev);
        int ret;
        u32 measurement;

        ret = gb_svc_pwrmon_intf_sample_get(intf->hd->svc, intf->interface_id,
                                            GB_SVC_PWRMON_TYPE_VOL,
                                            &measurement);
        if (ret) {
                dev_err(&intf->dev, "failed to get voltage sample (%d)\n", ret);
                return ret;
        }

        return sprintf(buf, "%u\n", measurement);
}
static DEVICE_ATTR_RO(voltage_now);

static ssize_t current_now_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct gb_interface *intf = to_gb_interface(dev);
        int ret;
        u32 measurement;

        ret = gb_svc_pwrmon_intf_sample_get(intf->hd->svc, intf->interface_id,
                                            GB_SVC_PWRMON_TYPE_CURR,
                                            &measurement);
        if (ret) {
                dev_err(&intf->dev, "failed to get current sample (%d)\n", ret);
                return ret;
        }

        return sprintf(buf, "%u\n", measurement);
}
static DEVICE_ATTR_RO(current_now);

static ssize_t power_now_show(struct device *dev,
                              struct device_attribute *attr, char *buf)
{
        struct gb_interface *intf = to_gb_interface(dev);
        int ret;
        u32 measurement;

        ret = gb_svc_pwrmon_intf_sample_get(intf->hd->svc, intf->interface_id,
                                            GB_SVC_PWRMON_TYPE_PWR,
                                            &measurement);
        if (ret) {
                dev_err(&intf->dev, "failed to get power sample (%d)\n", ret);
                return ret;
        }

        return sprintf(buf, "%u\n", measurement);
}
static DEVICE_ATTR_RO(power_now);

static ssize_t power_state_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct gb_interface *intf = to_gb_interface(dev);

        if (intf->active)
                return scnprintf(buf, PAGE_SIZE, "on\n");
        else
                return scnprintf(buf, PAGE_SIZE, "off\n");
}

static ssize_t power_state_store(struct device *dev,
                                 struct device_attribute *attr, const char *buf,
                                 size_t len)
{
        struct gb_interface *intf = to_gb_interface(dev);
        bool activate;
        int ret = 0;

        if (kstrtobool(buf, &activate))
                return -EINVAL;

        mutex_lock(&intf->mutex);

        if (activate == intf->active)
                goto unlock;

        if (activate) {
                ret = gb_interface_activate(intf);
                if (ret) {
                        dev_err(&intf->dev,
                                "failed to activate interface: %d\n", ret);
                        goto unlock;
                }

                ret = gb_interface_enable(intf);
                if (ret) {
                        dev_err(&intf->dev,
                                "failed to enable interface: %d\n", ret);
                        gb_interface_deactivate(intf);
                        goto unlock;
                }
        } else {
                gb_interface_disable(intf);
                gb_interface_deactivate(intf);
        }

unlock:
        mutex_unlock(&intf->mutex);

        if (ret)
                return ret;

        return len;
}
static DEVICE_ATTR_RW(power_state);

static const char *gb_interface_type_string(struct gb_interface *intf)
{
        static const char * const types[] = {
                [GB_INTERFACE_TYPE_INVALID] = "invalid",
                [GB_INTERFACE_TYPE_UNKNOWN] = "unknown",
                [GB_INTERFACE_TYPE_DUMMY] = "dummy",
                [GB_INTERFACE_TYPE_UNIPRO] = "unipro",
                [GB_INTERFACE_TYPE_GREYBUS] = "greybus",
        };

        return types[intf->type];
}

static ssize_t interface_type_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
{
        struct gb_interface *intf = to_gb_interface(dev);

        return sprintf(buf, "%s\n", gb_interface_type_string(intf));
}
static DEVICE_ATTR_RO(interface_type);

static struct attribute *interface_unipro_attrs[] = {
        &dev_attr_ddbl1_manufacturer_id.attr,
        &dev_attr_ddbl1_product_id.attr,
        NULL
};

static struct attribute *interface_greybus_attrs[] = {
        &dev_attr_vendor_id.attr,
        &dev_attr_product_id.attr,
        &dev_attr_serial_number.attr,
        NULL
};

static struct attribute *interface_power_attrs[] = {
        &dev_attr_voltage_now.attr,
        &dev_attr_current_now.attr,
        &dev_attr_power_now.attr,
        &dev_attr_power_state.attr,
        NULL
};

static struct attribute *interface_common_attrs[] = {
        &dev_attr_interface_id.attr,
        &dev_attr_interface_type.attr,
        NULL
};

static umode_t interface_unipro_is_visible(struct kobject *kobj,
                                                struct attribute *attr, int n)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct gb_interface *intf = to_gb_interface(dev);

        switch (intf->type) {
        case GB_INTERFACE_TYPE_UNIPRO:
        case GB_INTERFACE_TYPE_GREYBUS:
                return attr->mode;
        default:
                return 0;
        }
}

static umode_t interface_greybus_is_visible(struct kobject *kobj,
                                                struct attribute *attr, int n)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct gb_interface *intf = to_gb_interface(dev);

        switch (intf->type) {
        case GB_INTERFACE_TYPE_GREYBUS:
                return attr->mode;
        default:
                return 0;
        }
}

static umode_t interface_power_is_visible(struct kobject *kobj,
                                                struct attribute *attr, int n)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct gb_interface *intf = to_gb_interface(dev);

        switch (intf->type) {
        case GB_INTERFACE_TYPE_UNIPRO:
        case GB_INTERFACE_TYPE_GREYBUS:
                return attr->mode;
        default:
                return 0;
        }
}

static const struct attribute_group interface_unipro_group = {
        .is_visible     = interface_unipro_is_visible,
        .attrs          = interface_unipro_attrs,
};

static const struct attribute_group interface_greybus_group = {
        .is_visible     = interface_greybus_is_visible,
        .attrs          = interface_greybus_attrs,
};

static const struct attribute_group interface_power_group = {
        .is_visible     = interface_power_is_visible,
        .attrs          = interface_power_attrs,
};

static const struct attribute_group interface_common_group = {
        .attrs          = interface_common_attrs,
};

static const struct attribute_group *interface_groups[] = {
        &interface_unipro_group,
        &interface_greybus_group,
        &interface_power_group,
        &interface_common_group,
        NULL
};

static void gb_interface_release(struct device *dev)
{
        struct gb_interface *intf = to_gb_interface(dev);

        trace_gb_interface_release(intf);

        kfree(intf);
}

#ifdef CONFIG_PM
static int gb_interface_suspend(struct device *dev)
{
        struct gb_interface *intf = to_gb_interface(dev);
        int ret, timesync_ret;

        ret = gb_control_interface_suspend_prepare(intf->control);
        if (ret)
                return ret;

        gb_timesync_interface_remove(intf);

        ret = gb_control_suspend(intf->control);
        if (ret)
                goto err_hibernate_abort;

        ret = gb_interface_hibernate_link(intf);
        if (ret)
                return ret;

        /* Delay to allow interface to enter standby before disabling refclk */
        msleep(GB_INTERFACE_SUSPEND_HIBERNATE_DELAY_MS);

        ret = gb_interface_refclk_set(intf, false);
        if (ret)
                return ret;

        return 0;

err_hibernate_abort:
        gb_control_interface_hibernate_abort(intf->control);

        timesync_ret = gb_timesync_interface_add(intf);
        if (timesync_ret) {
                dev_err(dev, "failed to add to timesync: %d\n", timesync_ret);
                return timesync_ret;
        }

        return ret;
}

static int gb_interface_resume(struct device *dev)
{
        struct gb_interface *intf = to_gb_interface(dev);
        struct gb_svc *svc = intf->hd->svc;
        int ret;

        ret = gb_interface_refclk_set(intf, true);
        if (ret)
                return ret;

        ret = gb_svc_intf_resume(svc, intf->interface_id);
        if (ret)
                return ret;

        ret = gb_control_resume(intf->control);
        if (ret)
                return ret;

        ret = gb_timesync_interface_add(intf);
        if (ret) {
                dev_err(dev, "failed to add to timesync: %d\n", ret);
                return ret;
        }

        ret = gb_timesync_schedule_synchronous(intf);
        if (ret) {
                dev_err(dev, "failed to synchronize FrameTime: %d\n", ret);
                return ret;
        }

        return 0;
}

static int gb_interface_runtime_idle(struct device *dev)
{
        pm_runtime_mark_last_busy(dev);
        pm_request_autosuspend(dev);

        return 0;
}
#endif

static const struct dev_pm_ops gb_interface_pm_ops = {
        SET_RUNTIME_PM_OPS(gb_interface_suspend, gb_interface_resume,
                           gb_interface_runtime_idle)
};

struct device_type greybus_interface_type = {
        .name =         "greybus_interface",
        .release =      gb_interface_release,
        .pm =           &gb_interface_pm_ops,
};

/*
 * A Greybus module represents a user-replaceable component on a GMP
 * phone.  An interface is the physical connection on that module.  A
 * module may have more than one interface.
 *
 * Create a gb_interface structure to represent a discovered interface.
 * The position of interface within the Endo is encoded in "interface_id"
 * argument.
 *
 * Returns a pointer to the new interfce or a null pointer if a
 * failure occurs due to memory exhaustion.
 */
struct gb_interface *gb_interface_create(struct gb_module *module,
                                         u8 interface_id)
{
        struct gb_host_device *hd = module->hd;
        struct gb_interface *intf;

        intf = kzalloc(sizeof(*intf), GFP_KERNEL);
        if (!intf)
                return NULL;

        intf->hd = hd;          /* XXX refcount? */
        intf->module = module;
        intf->interface_id = interface_id;
        INIT_LIST_HEAD(&intf->bundles);
        INIT_LIST_HEAD(&intf->manifest_descs);
        mutex_init(&intf->mutex);
        INIT_WORK(&intf->mode_switch_work, gb_interface_mode_switch_work);
        init_completion(&intf->mode_switch_completion);

        /* Invalid device id to start with */
        intf->device_id = GB_INTERFACE_DEVICE_ID_BAD;

        intf->dev.parent = &module->dev;
        intf->dev.bus = &greybus_bus_type;
        intf->dev.type = &greybus_interface_type;
        intf->dev.groups = interface_groups;
        intf->dev.dma_mask = module->dev.dma_mask;
        device_initialize(&intf->dev);
        dev_set_name(&intf->dev, "%s.%u", dev_name(&module->dev),
                        interface_id);

        pm_runtime_set_autosuspend_delay(&intf->dev,
                                         GB_INTERFACE_AUTOSUSPEND_MS);

        trace_gb_interface_create(intf);

        return intf;
}

static int gb_interface_vsys_set(struct gb_interface *intf, bool enable)
{
        struct gb_svc *svc = intf->hd->svc;
        int ret;

        dev_dbg(&intf->dev, "%s - %d\n", __func__, enable);

        ret = gb_svc_intf_vsys_set(svc, intf->interface_id, enable);
        if (ret) {
                dev_err(&intf->dev, "failed to set v_sys: %d\n", ret);
                return ret;
        }

        return 0;
}

static int gb_interface_refclk_set(struct gb_interface *intf, bool enable)
{
        struct gb_svc *svc = intf->hd->svc;
        int ret;

        dev_dbg(&intf->dev, "%s - %d\n", __func__, enable);

        ret = gb_svc_intf_refclk_set(svc, intf->interface_id, enable);
        if (ret) {
                dev_err(&intf->dev, "failed to set refclk: %d\n", ret);
                return ret;
        }

        return 0;
}

static int gb_interface_unipro_set(struct gb_interface *intf, bool enable)
{
        struct gb_svc *svc = intf->hd->svc;
        int ret;

        dev_dbg(&intf->dev, "%s - %d\n", __func__, enable);

        ret = gb_svc_intf_unipro_set(svc, intf->interface_id, enable);
        if (ret) {
                dev_err(&intf->dev, "failed to set UniPro: %d\n", ret);
                return ret;
        }

        return 0;
}

static int gb_interface_activate_operation(struct gb_interface *intf,
                                           enum gb_interface_type *intf_type)
{
        struct gb_svc *svc = intf->hd->svc;
        u8 type;
        int ret;

        dev_dbg(&intf->dev, "%s\n", __func__);

        ret = gb_svc_intf_activate(svc, intf->interface_id, &type);
        if (ret) {
                dev_err(&intf->dev, "failed to activate: %d\n", ret);
                return ret;
        }

        switch (type) {
        case GB_SVC_INTF_TYPE_DUMMY:
                *intf_type = GB_INTERFACE_TYPE_DUMMY;
                /* FIXME: handle as an error for now */
                return -ENODEV;
        case GB_SVC_INTF_TYPE_UNIPRO:
                *intf_type = GB_INTERFACE_TYPE_UNIPRO;
                dev_err(&intf->dev, "interface type UniPro not supported\n");
                /* FIXME: handle as an error for now */
                return -ENODEV;
        case GB_SVC_INTF_TYPE_GREYBUS:
                *intf_type = GB_INTERFACE_TYPE_GREYBUS;
                break;
        default:
                dev_err(&intf->dev, "unknown interface type: %u\n", type);
                *intf_type = GB_INTERFACE_TYPE_UNKNOWN;
                return -ENODEV;
        }

        return 0;
}

static int gb_interface_hibernate_link(struct gb_interface *intf)
{
        struct gb_svc *svc = intf->hd->svc;

        return gb_svc_intf_set_power_mode_hibernate(svc, intf->interface_id);
}

static int _gb_interface_activate(struct gb_interface *intf,
                                  enum gb_interface_type *type)
{
        int ret;

        *type = GB_INTERFACE_TYPE_UNKNOWN;

        if (intf->ejected || intf->removed)
                return -ENODEV;

        ret = gb_interface_vsys_set(intf, true);
        if (ret)
                return ret;

        ret = gb_interface_refclk_set(intf, true);
        if (ret)
                goto err_vsys_disable;

        ret = gb_interface_unipro_set(intf, true);
        if (ret)
                goto err_refclk_disable;

        ret = gb_interface_activate_operation(intf, type);
        if (ret) {
                switch (*type) {
                case GB_INTERFACE_TYPE_UNIPRO:
                case GB_INTERFACE_TYPE_GREYBUS:
                        goto err_hibernate_link;
                default:
                        goto err_unipro_disable;
                }
        }

        ret = gb_interface_read_dme(intf);
        if (ret)
                goto err_hibernate_link;

        ret = gb_interface_route_create(intf);
        if (ret)
                goto err_hibernate_link;

        intf->active = true;

        trace_gb_interface_activate(intf);

        return 0;

err_hibernate_link:
        gb_interface_hibernate_link(intf);
err_unipro_disable:
        gb_interface_unipro_set(intf, false);
err_refclk_disable:
        gb_interface_refclk_set(intf, false);
err_vsys_disable:
        gb_interface_vsys_set(intf, false);

        return ret;
}

/*
 * At present, we assume a UniPro-only module to be a Greybus module that
 * failed to send its mailbox poke. There is some reason to believe that this
 * is because of a bug in the ES3 bootrom.

 *
 * FIXME: Check if this is a Toshiba bridge before retrying?
 */
static int _gb_interface_activate_es3_hack(struct gb_interface *intf,
                                           enum gb_interface_type *type)
{
        int retries = 3;
        int ret;

        while (retries--) {
                ret = _gb_interface_activate(intf, type);
                if (ret == -ENODEV && *type == GB_INTERFACE_TYPE_UNIPRO)
                        continue;

                break;
        }

        return ret;
}

/*
 * Activate an interface.
 *
 * Locking: Caller holds the interface mutex.
 */
int gb_interface_activate(struct gb_interface *intf)
{
        enum gb_interface_type type;
        int ret;

        switch (intf->type) {
        case GB_INTERFACE_TYPE_INVALID:
        case GB_INTERFACE_TYPE_GREYBUS:
                ret = _gb_interface_activate_es3_hack(intf, &type);
                break;
        default:
                ret = _gb_interface_activate(intf, &type);
        }

        /* Make sure type is detected correctly during reactivation. */
        if (intf->type != GB_INTERFACE_TYPE_INVALID) {
                if (type != intf->type) {
                        dev_err(&intf->dev, "failed to detect interface type\n");

                        if (!ret)
                                gb_interface_deactivate(intf);

                        return -EIO;
                }
        } else {
                intf->type = type;
        }

        return ret;
}

/*
 * Deactivate an interface.
 *
 * Locking: Caller holds the interface mutex.
 */
void gb_interface_deactivate(struct gb_interface *intf)
{
        if (!intf->active)
                return;

        trace_gb_interface_deactivate(intf);

        /* Abort any ongoing mode switch. */
        if (intf->mode_switch)
                complete(&intf->mode_switch_completion);

        gb_interface_route_destroy(intf);
        gb_interface_hibernate_link(intf);
        gb_interface_unipro_set(intf, false);
        gb_interface_refclk_set(intf, false);
        gb_interface_vsys_set(intf, false);

        intf->active = false;
}

/*
 * Enable an interface by enabling its control connection, fetching the
 * manifest and other information over it, and finally registering its child
 * devices.
 *
 * Locking: Caller holds the interface mutex.
 */
int gb_interface_enable(struct gb_interface *intf)
{
        struct gb_control *control;
        struct gb_bundle *bundle, *tmp;
        int ret, size;
        void *manifest;

        ret = gb_interface_read_and_clear_init_status(intf);
        if (ret) {
                dev_err(&intf->dev, "failed to clear init status: %d\n", ret);
                return ret;
        }

        /* Establish control connection */
        control = gb_control_create(intf);
        if (IS_ERR(control)) {
                dev_err(&intf->dev, "failed to create control device: %ld\n",
                                PTR_ERR(control));
                return PTR_ERR(control);
        }
        intf->control = control;

        ret = gb_control_enable(intf->control);
        if (ret)
                goto err_put_control;

        /* Get manifest size using control protocol on CPort */
        size = gb_control_get_manifest_size_operation(intf);
        if (size <= 0) {
                dev_err(&intf->dev, "failed to get manifest size: %d\n", size);

                if (size)
                        ret = size;
                else
                        ret =  -EINVAL;

                goto err_disable_control;
        }

        manifest = kmalloc(size, GFP_KERNEL);
        if (!manifest) {
                ret = -ENOMEM;
                goto err_disable_control;
        }

        /* Get manifest using control protocol on CPort */
        ret = gb_control_get_manifest_operation(intf, manifest, size);
        if (ret) {
                dev_err(&intf->dev, "failed to get manifest: %d\n", ret);
                goto err_free_manifest;
        }

        /*
         * Parse the manifest and build up our data structures representing
         * what's in it.
         */
        if (!gb_manifest_parse(intf, manifest, size)) {
                dev_err(&intf->dev, "failed to parse manifest\n");
                ret = -EINVAL;
                goto err_destroy_bundles;
        }

        ret = gb_control_get_bundle_versions(intf->control);
        if (ret)
                goto err_destroy_bundles;

        ret = gb_timesync_interface_add(intf);
        if (ret) {
                dev_err(&intf->dev, "failed to add to timesync: %d\n", ret);
                goto err_destroy_bundles;
        }

        /* Register the control device and any bundles */
        ret = gb_control_add(intf->control);
        if (ret)
                goto err_remove_timesync;

        pm_runtime_use_autosuspend(&intf->dev);
        pm_runtime_get_noresume(&intf->dev);
        pm_runtime_set_active(&intf->dev);
        pm_runtime_enable(&intf->dev);

        list_for_each_entry_safe_reverse(bundle, tmp, &intf->bundles, links) {
                ret = gb_bundle_add(bundle);
                if (ret) {
                        gb_bundle_destroy(bundle);
                        continue;
                }
        }

        kfree(manifest);

        intf->enabled = true;

        pm_runtime_put(&intf->dev);

        trace_gb_interface_enable(intf);

        return 0;

err_remove_timesync:
        gb_timesync_interface_remove(intf);
err_destroy_bundles:
        list_for_each_entry_safe(bundle, tmp, &intf->bundles, links)
                gb_bundle_destroy(bundle);
err_free_manifest:
        kfree(manifest);
err_disable_control:
        gb_control_disable(intf->control);
err_put_control:
        gb_control_put(intf->control);
        intf->control = NULL;

        return ret;
}

/*
 * Disable an interface and destroy its bundles.
 *
 * Locking: Caller holds the interface mutex.
 */
void gb_interface_disable(struct gb_interface *intf)
{
        struct gb_bundle *bundle;
        struct gb_bundle *next;

        if (!intf->enabled)
                return;

        trace_gb_interface_disable(intf);

        pm_runtime_get_sync(&intf->dev);

        /* Set disconnected flag to avoid I/O during connection tear down. */
        if (intf->quirks & GB_INTERFACE_QUIRK_FORCED_DISABLE)
                intf->disconnected = true;

        list_for_each_entry_safe(bundle, next, &intf->bundles, links)
                gb_bundle_destroy(bundle);

        if (!intf->mode_switch && !intf->disconnected)
                gb_control_interface_deactivate_prepare(intf->control);

        gb_control_del(intf->control);
        gb_timesync_interface_remove(intf);
        gb_control_disable(intf->control);
        gb_control_put(intf->control);
        intf->control = NULL;

        intf->enabled = false;

        pm_runtime_disable(&intf->dev);
        pm_runtime_set_suspended(&intf->dev);
        pm_runtime_dont_use_autosuspend(&intf->dev);
        pm_runtime_put_noidle(&intf->dev);
}

/* Enable TimeSync on an Interface control connection. */
int gb_interface_timesync_enable(struct gb_interface *intf, u8 count,
                                 u64 frame_time, u32 strobe_delay, u32 refclk)
{
        return gb_control_timesync_enable(intf->control, count,
                                          frame_time, strobe_delay,
                                          refclk);
}

/* Disable TimeSync on an Interface control connection. */
int gb_interface_timesync_disable(struct gb_interface *intf)
{
        return gb_control_timesync_disable(intf->control);
}

/* Transmit the Authoritative FrameTime via an Interface control connection. */
int gb_interface_timesync_authoritative(struct gb_interface *intf,
                                        u64 *frame_time)
{
        return gb_control_timesync_authoritative(intf->control,
                                                frame_time);
}

/* Register an interface. */
int gb_interface_add(struct gb_interface *intf)
{
        int ret;

        ret = device_add(&intf->dev);
        if (ret) {
                dev_err(&intf->dev, "failed to register interface: %d\n", ret);
                return ret;
        }

        trace_gb_interface_add(intf);

        dev_info(&intf->dev, "Interface added (%s)\n",
                        gb_interface_type_string(intf));

        switch (intf->type) {
        case GB_INTERFACE_TYPE_GREYBUS:
                dev_info(&intf->dev, "GMP VID=0x%08x, PID=0x%08x\n",
                                intf->vendor_id, intf->product_id);
                /* fall-through */
        case GB_INTERFACE_TYPE_UNIPRO:
                dev_info(&intf->dev, "DDBL1 Manufacturer=0x%08x, Product=0x%08x\n",
                                intf->ddbl1_manufacturer_id,
                                intf->ddbl1_product_id);
                break;
        default:
                break;
        }

        return 0;
}

/* Deregister an interface. */
void gb_interface_del(struct gb_interface *intf)
{
        if (device_is_registered(&intf->dev)) {
                trace_gb_interface_del(intf);

                device_del(&intf->dev);
                dev_info(&intf->dev, "Interface removed\n");
        }
}

void gb_interface_put(struct gb_interface *intf)
{
        put_device(&intf->dev);
}