/*
 * HD-audio core bus driver
 */

#include <linux/init.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/export.h>
#include <sound/hdaudio.h>
#include "trace.h"

static void process_unsol_events(struct work_struct *work);

static const struct hdac_bus_ops default_ops = {
        .command = snd_hdac_bus_send_cmd,
        .get_response = snd_hdac_bus_get_response,
};

/**
 * snd_hdac_bus_init - initialize a HD-audio bas bus
 * @bus: the pointer to bus object
 * @ops: bus verb operators
 * @io_ops: lowlevel I/O operators
 *
 * Returns 0 if successful, or a negative error code.
 */
int snd_hdac_bus_init(struct hdac_bus *bus, struct device *dev,
                      const struct hdac_bus_ops *ops,
                      const struct hdac_io_ops *io_ops)
{
        memset(bus, 0, sizeof(*bus));
        bus->dev = dev;
        if (ops)
                bus->ops = ops;
        else
                bus->ops = &default_ops;
        bus->io_ops = io_ops;
        INIT_LIST_HEAD(&bus->stream_list);
        INIT_LIST_HEAD(&bus->codec_list);
        INIT_WORK(&bus->unsol_work, process_unsol_events);
        spin_lock_init(&bus->reg_lock);
        mutex_init(&bus->cmd_mutex);
        bus->irq = -1;
        return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_init);

/**
 * snd_hdac_bus_exit - clean up a HD-audio bas bus
 * @bus: the pointer to bus object
 */
void snd_hdac_bus_exit(struct hdac_bus *bus)
{
        WARN_ON(!list_empty(&bus->stream_list));
        WARN_ON(!list_empty(&bus->codec_list));
        cancel_work_sync(&bus->unsol_work);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exit);

/**
 * snd_hdac_bus_exec_verb - execute a HD-audio verb on the given bus
 * @bus: bus object
 * @cmd: HD-audio encoded verb
 * @res: pointer to store the response, NULL if performing asynchronously
 *
 * Returns 0 if successful, or a negative error code.
 */
int snd_hdac_bus_exec_verb(struct hdac_bus *bus, unsigned int addr,
                           unsigned int cmd, unsigned int *res)
{
        int err;

        mutex_lock(&bus->cmd_mutex);
        err = snd_hdac_bus_exec_verb_unlocked(bus, addr, cmd, res);
        mutex_unlock(&bus->cmd_mutex);
        return err;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exec_verb);

/**
 * snd_hdac_bus_exec_verb_unlocked - unlocked version
 * @bus: bus object
 * @cmd: HD-audio encoded verb
 * @res: pointer to store the response, NULL if performing asynchronously
 *
 * Returns 0 if successful, or a negative error code.
 */
int snd_hdac_bus_exec_verb_unlocked(struct hdac_bus *bus, unsigned int addr,
                                    unsigned int cmd, unsigned int *res)
{
        unsigned int tmp;
        int err;

        if (cmd == ~0)
                return -EINVAL;

        if (res)
                *res = -1;
        else if (bus->sync_write)
                res = &tmp;
        for (;;) {
                trace_hda_send_cmd(bus, cmd);
                err = bus->ops->command(bus, cmd);
                if (err != -EAGAIN)
                        break;
                /* process pending verbs */
                err = bus->ops->get_response(bus, addr, &tmp);
                if (err)
                        break;
        }
        if (!err && res) {
                err = bus->ops->get_response(bus, addr, res);
                trace_hda_get_response(bus, addr, *res);
        }
        return err;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_exec_verb_unlocked);

/**
 * snd_hdac_bus_queue_event - add an unsolicited event to queue
 * @bus: the BUS
 * @res: unsolicited event (lower 32bit of RIRB entry)
 * @res_ex: codec addr and flags (upper 32bit or RIRB entry)
 *
 * Adds the given event to the queue.  The events are processed in
 * the workqueue asynchronously.  Call this function in the interrupt
 * hanlder when RIRB receives an unsolicited event.
 */
void snd_hdac_bus_queue_event(struct hdac_bus *bus, u32 res, u32 res_ex)
{
        unsigned int wp;

        if (!bus)
                return;

        trace_hda_unsol_event(bus, res, res_ex);
        wp = (bus->unsol_wp + 1) % HDA_UNSOL_QUEUE_SIZE;
        bus->unsol_wp = wp;

        wp <<= 1;
        bus->unsol_queue[wp] = res;
        bus->unsol_queue[wp + 1] = res_ex;

        schedule_work(&bus->unsol_work);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_queue_event);

/*
 * process queued unsolicited events
 */
static void process_unsol_events(struct work_struct *work)
{
        struct hdac_bus *bus = container_of(work, struct hdac_bus, unsol_work);
        struct hdac_device *codec;
        struct hdac_driver *drv;
        unsigned int rp, caddr, res;

        while (bus->unsol_rp != bus->unsol_wp) {
                rp = (bus->unsol_rp + 1) % HDA_UNSOL_QUEUE_SIZE;
                bus->unsol_rp = rp;
                rp <<= 1;
                res = bus->unsol_queue[rp];
                caddr = bus->unsol_queue[rp + 1];
                if (!(caddr & (1 << 4))) /* no unsolicited event? */
                        continue;
                codec = bus->caddr_tbl[caddr & 0x0f];
                if (!codec || !codec->dev.driver)
                        continue;
                drv = drv_to_hdac_driver(codec->dev.driver);
                if (drv->unsol_event)
                        drv->unsol_event(codec, res);
        }
}

/**
 * snd_hdac_bus_add_device - Add a codec to bus
 * @bus: HDA core bus
 * @codec: HDA core device to add
 *
 * Adds the given codec to the list in the bus.  The caddr_tbl array
 * and codec_powered bits are updated, as well.
 * Returns zero if success, or a negative error code.
 */
int snd_hdac_bus_add_device(struct hdac_bus *bus, struct hdac_device *codec)
{
        if (bus->caddr_tbl[codec->addr]) {
                dev_err(bus->dev, "address 0x%x is already occupied\n",
                        codec->addr);
                return -EBUSY;
        }

        list_add_tail(&codec->list, &bus->codec_list);
        bus->caddr_tbl[codec->addr] = codec;
        set_bit(codec->addr, &bus->codec_powered);
        bus->num_codecs++;
        return 0;
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_add_device);

/**
 * snd_hdac_bus_remove_device - Remove a codec from bus
 * @bus: HDA core bus
 * @codec: HDA core device to remove
 */
void snd_hdac_bus_remove_device(struct hdac_bus *bus,
                                struct hdac_device *codec)
{
        WARN_ON(bus != codec->bus);
        if (list_empty(&codec->list))
                return;
        list_del_init(&codec->list);
        bus->caddr_tbl[codec->addr] = NULL;
        clear_bit(codec->addr, &bus->codec_powered);
        bus->num_codecs--;
        flush_work(&bus->unsol_work);
}
EXPORT_SYMBOL_GPL(snd_hdac_bus_remove_device);