// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2011-2017, The Linux Foundation
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pm_runtime.h>
#include <linux/slimbus.h>
#include "slimbus.h"

static DEFINE_IDA(ctrl_ida);

static const struct slim_device_id *slim_match(const struct slim_device_id *id,
                                               const struct slim_device *sbdev)
{
        while (id->manf_id != 0 || id->prod_code != 0) {
                if (id->manf_id == sbdev->e_addr.manf_id &&
                    id->prod_code == sbdev->e_addr.prod_code &&
                    id->dev_index == sbdev->e_addr.dev_index &&
                    id->instance == sbdev->e_addr.instance)
                        return id;
                id++;
        }
        return NULL;
}

static int slim_device_match(struct device *dev, struct device_driver *drv)
{
        struct slim_device *sbdev = to_slim_device(dev);
        struct slim_driver *sbdrv = to_slim_driver(drv);

        /* Attempt an OF style match first */
        if (of_driver_match_device(dev, drv))
                return 1;

        return !!slim_match(sbdrv->id_table, sbdev);
}

static void slim_device_update_status(struct slim_device *sbdev,
                                      enum slim_device_status status)
{
        struct slim_driver *sbdrv;

        if (sbdev->status == status)
                return;

        sbdev->status = status;
        if (!sbdev->dev.driver)
                return;

        sbdrv = to_slim_driver(sbdev->dev.driver);
        if (sbdrv->device_status)
                sbdrv->device_status(sbdev, sbdev->status);
}

static int slim_device_probe(struct device *dev)
{
        struct slim_device      *sbdev = to_slim_device(dev);
        struct slim_driver      *sbdrv = to_slim_driver(dev->driver);
        int ret;

        ret = sbdrv->probe(sbdev);
        if (ret)
                return ret;

        /* try getting the logical address after probe */
        ret = slim_get_logical_addr(sbdev);
        if (!ret) {
                slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP);
        } else {
                dev_err(&sbdev->dev, "Failed to get logical address\n");
                ret = -EPROBE_DEFER;
        }

        return ret;
}

static int slim_device_remove(struct device *dev)
{
        struct slim_device *sbdev = to_slim_device(dev);
        struct slim_driver *sbdrv;

        if (dev->driver) {
                sbdrv = to_slim_driver(dev->driver);
                if (sbdrv->remove)
                        sbdrv->remove(sbdev);
        }

        return 0;
}

static int slim_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
        struct slim_device *sbdev = to_slim_device(dev);

        return add_uevent_var(env, "MODALIAS=slim:%s", dev_name(&sbdev->dev));
}

struct bus_type slimbus_bus = {
        .name           = "slimbus",
        .match          = slim_device_match,
        .probe          = slim_device_probe,
        .remove         = slim_device_remove,
        .uevent         = slim_device_uevent,
};
EXPORT_SYMBOL_GPL(slimbus_bus);

/*
 * __slim_driver_register() - Client driver registration with SLIMbus
 *
 * @drv:Client driver to be associated with client-device.
 * @owner: owning module/driver
 *
 * This API will register the client driver with the SLIMbus
 * It is called from the driver's module-init function.
 */
int __slim_driver_register(struct slim_driver *drv, struct module *owner)
{
        /* ID table and probe are mandatory */
        if (!(drv->driver.of_match_table || drv->id_table) || !drv->probe)
                return -EINVAL;

        drv->driver.bus = &slimbus_bus;
        drv->driver.owner = owner;

        return driver_register(&drv->driver);
}
EXPORT_SYMBOL_GPL(__slim_driver_register);

/*
 * slim_driver_unregister() - Undo effect of slim_driver_register
 *
 * @drv: Client driver to be unregistered
 */
void slim_driver_unregister(struct slim_driver *drv)
{
        driver_unregister(&drv->driver);
}
EXPORT_SYMBOL_GPL(slim_driver_unregister);

static void slim_dev_release(struct device *dev)
{
        struct slim_device *sbdev = to_slim_device(dev);

        kfree(sbdev);
}

static int slim_add_device(struct slim_controller *ctrl,
                           struct slim_device *sbdev,
                           struct device_node *node)
{
        sbdev->dev.bus = &slimbus_bus;
        sbdev->dev.parent = ctrl->dev;
        sbdev->dev.release = slim_dev_release;
        sbdev->dev.driver = NULL;
        sbdev->ctrl = ctrl;
        INIT_LIST_HEAD(&sbdev->stream_list);
        spin_lock_init(&sbdev->stream_list_lock);
        sbdev->dev.of_node = of_node_get(node);
        sbdev->dev.fwnode = of_fwnode_handle(node);

        dev_set_name(&sbdev->dev, "%x:%x:%x:%x",
                                  sbdev->e_addr.manf_id,
                                  sbdev->e_addr.prod_code,
                                  sbdev->e_addr.dev_index,
                                  sbdev->e_addr.instance);

        return device_register(&sbdev->dev);
}

static struct slim_device *slim_alloc_device(struct slim_controller *ctrl,
                                             struct slim_eaddr *eaddr,
                                             struct device_node *node)
{
        struct slim_device *sbdev;
        int ret;

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

        sbdev->e_addr = *eaddr;
        ret = slim_add_device(ctrl, sbdev, node);
        if (ret) {
                put_device(&sbdev->dev);
                return NULL;
        }

        return sbdev;
}

static void of_register_slim_devices(struct slim_controller *ctrl)
{
        struct device *dev = ctrl->dev;
        struct device_node *node;

        if (!ctrl->dev->of_node)
                return;

        for_each_child_of_node(ctrl->dev->of_node, node) {
                struct slim_device *sbdev;
                struct slim_eaddr e_addr;
                const char *compat = NULL;
                int reg[2], ret;
                int manf_id, prod_code;

                compat = of_get_property(node, "compatible", NULL);
                if (!compat)
                        continue;

                ret = sscanf(compat, "slim%x,%x", &manf_id, &prod_code);
                if (ret != 2) {
                        dev_err(dev, "Manf ID & Product code not found %s\n",
                                compat);
                        continue;
                }

                ret = of_property_read_u32_array(node, "reg", reg, 2);
                if (ret) {
                        dev_err(dev, "Device and Instance id not found:%d\n",
                                ret);
                        continue;
                }

                e_addr.dev_index = reg[0];
                e_addr.instance = reg[1];
                e_addr.manf_id = manf_id;
                e_addr.prod_code = prod_code;

                sbdev = slim_alloc_device(ctrl, &e_addr, node);
                if (!sbdev)
                        continue;
        }
}

/*
 * slim_register_controller() - Controller bring-up and registration.
 *
 * @ctrl: Controller to be registered.
 *
 * A controller is registered with the framework using this API.
 * If devices on a controller were registered before controller,
 * this will make sure that they get probed when controller is up
 */
int slim_register_controller(struct slim_controller *ctrl)
{
        int id;

        id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
        if (id < 0)
                return id;

        ctrl->id = id;

        if (!ctrl->min_cg)
                ctrl->min_cg = SLIM_MIN_CLK_GEAR;
        if (!ctrl->max_cg)
                ctrl->max_cg = SLIM_MAX_CLK_GEAR;

        ida_init(&ctrl->laddr_ida);
        idr_init(&ctrl->tid_idr);
        mutex_init(&ctrl->lock);
        mutex_init(&ctrl->sched.m_reconf);
        init_completion(&ctrl->sched.pause_comp);
        spin_lock_init(&ctrl->txn_lock);

        dev_dbg(ctrl->dev, "Bus [%s] registered:dev:%p\n",
                ctrl->name, ctrl->dev);

        of_register_slim_devices(ctrl);

        return 0;
}
EXPORT_SYMBOL_GPL(slim_register_controller);

/* slim_remove_device: Remove the effect of slim_add_device() */
static void slim_remove_device(struct slim_device *sbdev)
{
        of_node_put(sbdev->dev.of_node);
        device_unregister(&sbdev->dev);
}

static int slim_ctrl_remove_device(struct device *dev, void *null)
{
        slim_remove_device(to_slim_device(dev));
        return 0;
}

/**
 * slim_unregister_controller() - Controller tear-down.
 *
 * @ctrl: Controller to tear-down.
 */
int slim_unregister_controller(struct slim_controller *ctrl)
{
        /* Remove all clients */
        device_for_each_child(ctrl->dev, NULL, slim_ctrl_remove_device);
        /* Enter Clock Pause */
        slim_ctrl_clk_pause(ctrl, false, 0);
        ida_simple_remove(&ctrl_ida, ctrl->id);

        return 0;
}
EXPORT_SYMBOL_GPL(slim_unregister_controller);

/**
 * slim_report_absent() - Controller calls this function when a device
 *      reports absent, OR when the device cannot be communicated with
 *
 * @sbdev: Device that cannot be reached, or sent report absent
 */
void slim_report_absent(struct slim_device *sbdev)
{
        struct slim_controller *ctrl = sbdev->ctrl;

        if (!ctrl)
                return;

        /* invalidate logical addresses */
        mutex_lock(&ctrl->lock);
        sbdev->is_laddr_valid = false;
        mutex_unlock(&ctrl->lock);

        ida_simple_remove(&ctrl->laddr_ida, sbdev->laddr);
        slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_DOWN);
}
EXPORT_SYMBOL_GPL(slim_report_absent);

static bool slim_eaddr_equal(struct slim_eaddr *a, struct slim_eaddr *b)
{
        return (a->manf_id == b->manf_id &&
                a->prod_code == b->prod_code &&
                a->dev_index == b->dev_index &&
                a->instance == b->instance);
}

static int slim_match_dev(struct device *dev, void *data)
{
        struct slim_eaddr *e_addr = data;
        struct slim_device *sbdev = to_slim_device(dev);

        return slim_eaddr_equal(&sbdev->e_addr, e_addr);
}

static struct slim_device *find_slim_device(struct slim_controller *ctrl,
                                            struct slim_eaddr *eaddr)
{
        struct slim_device *sbdev;
        struct device *dev;

        dev = device_find_child(ctrl->dev, eaddr, slim_match_dev);
        if (dev) {
                sbdev = to_slim_device(dev);
                return sbdev;
        }

        return NULL;
}

/**
 * slim_get_device() - get handle to a device.
 *
 * @ctrl: Controller on which this device will be added/queried
 * @e_addr: Enumeration address of the device to be queried
 *
 * Return: pointer to a device if it has already reported. Creates a new
 * device and returns pointer to it if the device has not yet enumerated.
 */
struct slim_device *slim_get_device(struct slim_controller *ctrl,
                                    struct slim_eaddr *e_addr)
{
        struct slim_device *sbdev;

        sbdev = find_slim_device(ctrl, e_addr);
        if (!sbdev) {
                sbdev = slim_alloc_device(ctrl, e_addr, NULL);
                if (!sbdev)
                        return ERR_PTR(-ENOMEM);
        }

        return sbdev;
}
EXPORT_SYMBOL_GPL(slim_get_device);

static int of_slim_match_dev(struct device *dev, void *data)
{
        struct device_node *np = data;
        struct slim_device *sbdev = to_slim_device(dev);

        return (sbdev->dev.of_node == np);
}

static struct slim_device *of_find_slim_device(struct slim_controller *ctrl,
                                               struct device_node *np)
{
        struct slim_device *sbdev;
        struct device *dev;

        dev = device_find_child(ctrl->dev, np, of_slim_match_dev);
        if (dev) {
                sbdev = to_slim_device(dev);
                return sbdev;
        }

        return NULL;
}

/**
 * of_slim_get_device() - get handle to a device using dt node.
 *
 * @ctrl: Controller on which this device will be added/queried
 * @np: node pointer to device
 *
 * Return: pointer to a device if it has already reported. Creates a new
 * device and returns pointer to it if the device has not yet enumerated.
 */
struct slim_device *of_slim_get_device(struct slim_controller *ctrl,
                                       struct device_node *np)
{
        return of_find_slim_device(ctrl, np);
}
EXPORT_SYMBOL_GPL(of_slim_get_device);

static int slim_device_alloc_laddr(struct slim_device *sbdev,
                                   bool report_present)
{
        struct slim_controller *ctrl = sbdev->ctrl;
        u8 laddr;
        int ret;

        mutex_lock(&ctrl->lock);
        if (ctrl->get_laddr) {
                ret = ctrl->get_laddr(ctrl, &sbdev->e_addr, &laddr);
                if (ret < 0)
                        goto err;
        } else if (report_present) {
                ret = ida_simple_get(&ctrl->laddr_ida,
                                     0, SLIM_LA_MANAGER - 1, GFP_KERNEL);
                if (ret < 0)
                        goto err;

                laddr = ret;
        } else {
                ret = -EINVAL;
                goto err;
        }

        if (ctrl->set_laddr) {
                ret = ctrl->set_laddr(ctrl, &sbdev->e_addr, laddr);
                if (ret) {
                        ret = -EINVAL;
                        goto err;
                }
        }

        sbdev->laddr = laddr;
        sbdev->is_laddr_valid = true;
        mutex_unlock(&ctrl->lock);

        slim_device_update_status(sbdev, SLIM_DEVICE_STATUS_UP);

        dev_dbg(ctrl->dev, "setting slimbus l-addr:%x, ea:%x,%x,%x,%x\n",
                laddr, sbdev->e_addr.manf_id, sbdev->e_addr.prod_code,
                sbdev->e_addr.dev_index, sbdev->e_addr.instance);

        return 0;

err:
        mutex_unlock(&ctrl->lock);
        return ret;

}

/**
 * slim_device_report_present() - Report enumerated device.
 *
 * @ctrl: Controller with which device is enumerated.
 * @e_addr: Enumeration address of the device.
 * @laddr: Return logical address (if valid flag is false)
 *
 * Called by controller in response to REPORT_PRESENT. Framework will assign
 * a logical address to this enumeration address.
 * Function returns -EXFULL to indicate that all logical addresses are already
 * taken.
 */
int slim_device_report_present(struct slim_controller *ctrl,
                               struct slim_eaddr *e_addr, u8 *laddr)
{
        struct slim_device *sbdev;
        int ret;

        ret = pm_runtime_get_sync(ctrl->dev);

        if (ctrl->sched.clk_state != SLIM_CLK_ACTIVE) {
                dev_err(ctrl->dev, "slim ctrl not active,state:%d, ret:%d\n",
                                    ctrl->sched.clk_state, ret);
                goto slimbus_not_active;
        }

        sbdev = slim_get_device(ctrl, e_addr);
        if (IS_ERR(sbdev))
                return -ENODEV;

        if (sbdev->is_laddr_valid) {
                *laddr = sbdev->laddr;
                return 0;
        }

        ret = slim_device_alloc_laddr(sbdev, true);

slimbus_not_active:
        pm_runtime_mark_last_busy(ctrl->dev);
        pm_runtime_put_autosuspend(ctrl->dev);
        return ret;
}
EXPORT_SYMBOL_GPL(slim_device_report_present);

/**
 * slim_get_logical_addr() - get/allocate logical address of a SLIMbus device.
 *
 * @sbdev: client handle requesting the address.
 *
 * Return: zero if a logical address is valid or a new logical address
 * has been assigned. error code in case of error.
 */
int slim_get_logical_addr(struct slim_device *sbdev)
{
        if (!sbdev->is_laddr_valid)
                return slim_device_alloc_laddr(sbdev, false);

        return 0;
}
EXPORT_SYMBOL_GPL(slim_get_logical_addr);

static void __exit slimbus_exit(void)
{
        bus_unregister(&slimbus_bus);
}
module_exit(slimbus_exit);

static int __init slimbus_init(void)
{
        return bus_register(&slimbus_bus);
}
postcore_initcall(slimbus_init);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("SLIMbus core");