/*
 * Greybus Module code
 *
 * Copyright 2016 Google Inc.
 * Copyright 2016 Linaro Ltd.
 *
 * Released under the GPLv2 only.
 */

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


static ssize_t eject_store(struct device *dev,
                                struct device_attribute *attr,
                                const char *buf, size_t len)
{
        struct gb_module *module = to_gb_module(dev);
        struct gb_interface *intf;
        size_t i;
        long val;
        int ret;

        ret = kstrtol(buf, 0, &val);
        if (ret)
                return ret;

        if (!val)
                return len;

        for (i = 0; i < module->num_interfaces; ++i) {
                intf = module->interfaces[i];

                mutex_lock(&intf->mutex);
                /* Set flag to prevent concurrent activation. */
                intf->ejected = true;
                gb_interface_disable(intf);
                gb_interface_deactivate(intf);
                mutex_unlock(&intf->mutex);
        }

        /* Tell the SVC to eject the primary interface. */
        ret = gb_svc_intf_eject(module->hd->svc, module->module_id);
        if (ret)
                return ret;

        return len;
}
static DEVICE_ATTR_WO(eject);

static ssize_t module_id_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct gb_module *module = to_gb_module(dev);

        return sprintf(buf, "%u\n", module->module_id);
}
static DEVICE_ATTR_RO(module_id);

static ssize_t num_interfaces_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct gb_module *module = to_gb_module(dev);

        return sprintf(buf, "%zu\n", module->num_interfaces);
}
static DEVICE_ATTR_RO(num_interfaces);

static struct attribute *module_attrs[] = {
        &dev_attr_eject.attr,
        &dev_attr_module_id.attr,
        &dev_attr_num_interfaces.attr,
        NULL,
};
ATTRIBUTE_GROUPS(module);

static void gb_module_release(struct device *dev)
{
        struct gb_module *module = to_gb_module(dev);

        trace_gb_module_release(module);

        kfree(module);
}

struct device_type greybus_module_type = {
        .name           = "greybus_module",
        .release        = gb_module_release,
};

struct gb_module *gb_module_create(struct gb_host_device *hd, u8 module_id,
                                        size_t num_interfaces)
{
        struct gb_interface *intf;
        struct gb_module *module;
        int i;

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

        module->hd = hd;
        module->module_id = module_id;
        module->num_interfaces = num_interfaces;

        module->dev.parent = &hd->dev;
        module->dev.bus = &greybus_bus_type;
        module->dev.type = &greybus_module_type;
        module->dev.groups = module_groups;
        module->dev.dma_mask = hd->dev.dma_mask;
        device_initialize(&module->dev);
        dev_set_name(&module->dev, "%d-%u", hd->bus_id, module_id);

        trace_gb_module_create(module);

        for (i = 0; i < num_interfaces; ++i) {
                intf = gb_interface_create(module, module_id + i);
                if (!intf) {
                        dev_err(&module->dev, "failed to create interface %u\n",
                                        module_id + i);
                        goto err_put_interfaces;
                }
                module->interfaces[i] = intf;
        }

        return module;

err_put_interfaces:
        for (--i; i >= 0; --i)
                gb_interface_put(module->interfaces[i]);

        put_device(&module->dev);

        return NULL;
}

/*
 * Register and enable an interface after first attempting to activate it.
 */
static void gb_module_register_interface(struct gb_interface *intf)
{
        struct gb_module *module = intf->module;
        u8 intf_id = intf->interface_id;
        int ret;

        mutex_lock(&intf->mutex);

        ret = gb_interface_activate(intf);
        if (ret) {
                if (intf->type != GB_INTERFACE_TYPE_DUMMY) {
                        dev_err(&module->dev,
                                        "failed to activate interface %u: %d\n",
                                        intf_id, ret);
                }

                gb_interface_add(intf);
                goto err_unlock;
        }

        ret = gb_interface_add(intf);
        if (ret)
                goto err_interface_deactivate;

        ret = gb_interface_enable(intf);
        if (ret) {
                dev_err(&module->dev, "failed to enable interface %u: %d\n",
                                intf_id, ret);
                goto err_interface_deactivate;
        }

        mutex_unlock(&intf->mutex);

        return;

err_interface_deactivate:
        gb_interface_deactivate(intf);
err_unlock:
        mutex_unlock(&intf->mutex);
}

static void gb_module_deregister_interface(struct gb_interface *intf)
{
        /* Mark as disconnected to prevent I/O during disable. */
        if (intf->module->disconnected)
                intf->disconnected = true;

        mutex_lock(&intf->mutex);
        intf->removed = true;
        gb_interface_disable(intf);
        gb_interface_deactivate(intf);
        mutex_unlock(&intf->mutex);

        gb_interface_del(intf);
}

/* Register a module and its interfaces. */
int gb_module_add(struct gb_module *module)
{
        size_t i;
        int ret;

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

        trace_gb_module_add(module);

        for (i = 0; i < module->num_interfaces; ++i)
                gb_module_register_interface(module->interfaces[i]);

        return 0;
}

/* Deregister a module and its interfaces. */
void gb_module_del(struct gb_module *module)
{
        size_t i;

        for (i = 0; i < module->num_interfaces; ++i)
                gb_module_deregister_interface(module->interfaces[i]);

        trace_gb_module_del(module);

        device_del(&module->dev);
}

void gb_module_put(struct gb_module *module)
{
        size_t i;

        for (i = 0; i < module->num_interfaces; ++i)
                gb_interface_put(module->interfaces[i]);

        put_device(&module->dev);
}