linux-imx

/*

 * isochronous resources helper functions

 *

 * Copyright (c) Clemens Ladisch <clemens@ladisch.de>

 * Licensed under the terms of the GNU General Public License, version 2.

 */

​

#include <linux/device.h>

#include <linux/firewire.h>

#include <linux/firewire-constants.h>

#include <linux/export.h>

#include <linux/jiffies.h>

#include <linux/mutex.h>

#include <linux/sched.h>

#include <linux/spinlock.h>

#include "iso-resources.h"

​

/**

 * fw_iso_resources_init - initializes a &struct fw_iso_resources

 * @r: the resource manager to initialize

 * @unit: the device unit for which the resources will be needed

 *

 * If the device does not support all channel numbers, change @r->channels_mask

 * after calling this function.

 */

int fw_iso_resources_init(struct fw_iso_resources *r, struct fw_unit *unit)

{

    r->channels_mask = ~0uLL;

    r->unit = unit;

    mutex_init(&r->mutex);

    r->allocated = false;

​

    return 0;

}

EXPORT_SYMBOL(fw_iso_resources_init);

​

/**

 * fw_iso_resources_destroy - destroy a resource manager

 * @r: the resource manager that is no longer needed

 */

void fw_iso_resources_destroy(struct fw_iso_resources *r)

{

    WARN_ON(r->allocated);

    mutex_destroy(&r->mutex);

}

EXPORT_SYMBOL(fw_iso_resources_destroy);

​

static unsigned int packet_bandwidth(unsigned int max_payload_bytes, int speed)

{

    unsigned int bytes, s400_bytes;

​

    /* iso packets have three header quadlets and quadlet-aligned payload */

    bytes = 3 * 4 + ALIGN(max_payload_bytes, 4);

​

    /* convert to bandwidth units (quadlets at S1600 = bytes at S400) */

    if (speed <= SCODE_400)

        s400_bytes = bytes * (1 << (SCODE_400 - speed));

    else

        s400_bytes = DIV_ROUND_UP(bytes, 1 << (speed - SCODE_400));

​

    return s400_bytes;

}

​