dvb_ca_en50221.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,628 行 · 第 1/4 页

                fragbuf[0] = connection_id;
                fragbuf[1] = ((fragpos + fraglen) < count) ? 0x80 : 0x00;
                if ((status = copy_from_user(fragbuf+2, buf+fragpos, fraglen)) != 0) goto exit;

		timeout = jiffies + HZ/2;
	        written = 0;
                while(!time_after(jiffies, timeout)) {
                        status = dvb_ca_en50221_write_data(ca, slot, fragbuf, fraglen+2);
		        if (status == (fraglen+2)) {
			       written = 1;
			       break;
			}
                        if (status != -EAGAIN) goto exit;

                        dvb_delay(1);
                }
	        if (!written) {
		        status = -EIO;
		        goto exit;
		}

                fragpos += fraglen;
        }
        status = count + 2;

exit:
        return status;
}


/**
 * Condition for waking up in dvb_ca_en50221_io_read_condition
 */
static int dvb_ca_en50221_io_read_condition(struct dvb_ca_private* ca, int* result, int* _slot)
{
        int slot;
        int slot_count = 0;
        int idx;
        size_t fraglen;
        int connection_id = -1;
        int found = 0;
        u8 hdr[2];

        slot = ca->next_read_slot;
        while((slot_count < ca->slot_count) && (!found)) {
                if (ca->slot_info[slot].slot_state != DVB_CA_SLOTSTATE_RUNNING) goto nextslot;

                if ((*result = down_interruptible(&ca->slot_info[slot].sem)) != 0) return 1;

                idx = dvb_ringbuffer_pkt_next(&ca->slot_info[slot].rx_buffer, -1, &fraglen);
                while(idx != -1) {
                        dvb_ringbuffer_pkt_read(&ca->slot_info[slot].rx_buffer, idx, 0, hdr, 2, 0);
                        if (connection_id == -1) connection_id = hdr[0];
                        if ((hdr[0] == connection_id) && ((hdr[1] & 0x80) == 0)) {
                                *_slot = slot;
                                found = 1;
                                break;
                        }

                        idx = dvb_ringbuffer_pkt_next(&ca->slot_info[slot].rx_buffer, idx, &fraglen);
                }

                if (!found) up(&ca->slot_info[slot].sem);

nextslot:
                slot = (slot + 1) % ca->slot_count;
                slot_count++;
        }

        ca->next_read_slot = slot;
        return found;
}


/**
 * Implementation of read() syscall.
 *
 * @param file File structure.
 * @param buf Destination buffer.
 * @param count Size of destination buffer.
 * @param ppos Position in file (ignored).
 *
 * @return Number of bytes read, or <0 on error.
 */
static ssize_t dvb_ca_en50221_io_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
        struct dvb_device *dvbdev=(struct dvb_device *) file->private_data;
        struct dvb_ca_private *ca=(struct dvb_ca_private*) dvbdev->priv;
        int status;
        int result = 0;
        u8 hdr[2];
        int slot;
        int connection_id = -1;
        size_t idx, idx2;
        int last_fragment = 0;
        size_t fraglen;
        int pktlen;
        int dispose = 0;

        dprintk ("%s\n", __FUNCTION__);

        /* Outgoing packet has a 2 byte header. hdr[0] = slot_id, hdr[1] = connection_id */
        if (count < 2) return -EINVAL;

        /* wait for some data */
        if ((status = dvb_ca_en50221_io_read_condition(ca, &result, &slot)) == 0) {

                /* if we're in nonblocking mode, exit immediately */
                if (file->f_flags & O_NONBLOCK) return -EWOULDBLOCK;

                /* wait for some data */
                status = wait_event_interruptible(ca->wait_queue, dvb_ca_en50221_io_read_condition(ca, &result, &slot));
        }
        if ((status < 0) || (result < 0)) {
                if (result) return result;
                return status;
        }

        idx = dvb_ringbuffer_pkt_next(&ca->slot_info[slot].rx_buffer, -1, &fraglen);
        pktlen = 2;
        do {
                if (idx == -1) {
                        printk("dvb_ca: BUG: read packet ended before last_fragment encountered\n");
                        status = -EIO;
                        goto exit;
                }

                dvb_ringbuffer_pkt_read(&ca->slot_info[slot].rx_buffer, idx, 0, hdr, 2, 0);
                if (connection_id == -1) connection_id = hdr[0];
                if (hdr[0] == connection_id) {
                        if (pktlen < count) {
                                if ((pktlen + fraglen - 2) > count) {
                                        fraglen = count - pktlen;
                                } else {
                                        fraglen -= 2;
                                }

			        if ((status = dvb_ringbuffer_pkt_read(&ca->slot_info[slot].rx_buffer, idx, 2, buf + pktlen, fraglen, 1)) < 0) {
                                        goto exit;
                                }
                                pktlen += fraglen;
                        }

                        if ((hdr[1] & 0x80) == 0) last_fragment = 1;
                        dispose = 1;
                }

                idx2 = dvb_ringbuffer_pkt_next(&ca->slot_info[slot].rx_buffer, idx, &fraglen);
                if (dispose) dvb_ringbuffer_pkt_dispose(&ca->slot_info[slot].rx_buffer, idx);
                idx = idx2;
                dispose = 0;
        } while (!last_fragment);

        hdr[0] = slot;
        hdr[1] = connection_id;
        if ((status = copy_to_user(buf, hdr, 2)) != 0) goto exit;
        status = pktlen;

exit:
        up(&ca->slot_info[slot].sem);
        return status;
}


/**
 * Implementation of file open syscall.
 *
 * @param inode Inode concerned.
 * @param file File concerned.
 *
 * @return 0 on success, <0 on failure.
 */
static int dvb_ca_en50221_io_open(struct inode *inode, struct file *file)
{
        struct dvb_device *dvbdev = (struct dvb_device *) file->private_data;
        struct dvb_ca_private *ca = (struct dvb_ca_private*) dvbdev->priv;
        int err;
        int i;

        dprintk ("%s\n", __FUNCTION__);

        err=dvb_generic_open(inode, file);
        if (err<0)
                return err;

        for(i=0; i< ca->slot_count; i++) {
                if (ca->slot_info[i].slot_state == DVB_CA_SLOTSTATE_RUNNING) {
                        dvb_ringbuffer_flush(&ca->slot_info[i].rx_buffer);
                }
        }

        ca->open = 1;
        dvb_ca_en50221_thread_update_delay(ca);
        dvb_ca_en50221_thread_wakeup(ca);

        return 0;
}


/**
 * Implementation of file close syscall.
 *
 * @param inode Inode concerned.
 * @param file File concerned.
 *
 * @return 0 on success, <0 on failure.
 */
static int dvb_ca_en50221_io_release(struct inode *inode, struct file *file)
{
        struct dvb_device *dvbdev=(struct dvb_device *) file->private_data;
        struct dvb_ca_private *ca=(struct dvb_ca_private*) dvbdev->priv;
        int err;

        dprintk ("%s\n", __FUNCTION__);

        /* mark the CA device as closed */
        ca->open = 0;
        dvb_ca_en50221_thread_update_delay(ca);

        err=dvb_generic_release(inode, file);
        if (err<0)
                return err;
        return 0;
}


/**
 * Implementation of poll() syscall.
 *
 * @param file File concerned.
 * @param wait poll wait table.
 *
 * @return Standard poll mask.
 */
static unsigned int dvb_ca_en50221_io_poll(struct file *file, poll_table *wait)
{
        struct dvb_device* dvbdev = (struct dvb_device*) file->private_data;
        struct dvb_ca_private* ca = (struct dvb_ca_private*) dvbdev->priv;
        unsigned int mask=0;
        int slot;
        int result = 0;

        dprintk ("%s\n", __FUNCTION__);

        if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) {
                up(&ca->slot_info[slot].sem);
                mask |= POLLIN;
        }

        /* if there is something, return now */
        if (mask) return mask;

        /* wait for something to happen */
        poll_wait(file, &ca->wait_queue, wait);

        if (dvb_ca_en50221_io_read_condition(ca, &result, &slot) == 1) {
                up(&ca->slot_info[slot].sem);
                mask |= POLLIN;
        }

        return mask;
}


static struct file_operations dvb_ca_fops = {
        .owner = THIS_MODULE,
        .read = dvb_ca_en50221_io_read,
        .write = dvb_ca_en50221_io_write,
        .ioctl = dvb_ca_en50221_io_ioctl,
        .open = dvb_ca_en50221_io_open,
        .release = dvb_ca_en50221_io_release,
        .poll = dvb_ca_en50221_io_poll,
};

static struct dvb_device dvbdev_ca = {
        .users = 1,
        .readers = 1,
        .writers = 1,
        .fops = &dvb_ca_fops,
};


/* ******************************************************************************** */
/* Initialisation/shutdown functions */


/**
 * Initialise a new DVB CA EN50221 interface device.
 *
 * @param dvb_adapter DVB adapter to attach the new CA device to.
 * @param ca The dvb_ca instance.
 * @param flags Flags describing the CA device (DVB_CA_FLAG_*).
 * @param slot_count Number of slots supported.
 *
 * @return 0 on success, nonzero on failure
 */
int dvb_ca_en50221_init(struct dvb_adapter *dvb_adapter, struct dvb_ca_en50221* pubca, int flags, int slot_count)
{
        int ret;
        struct dvb_ca_private* ca = NULL;
        int i;

        dprintk ("%s\n", __FUNCTION__);

        if (slot_count < 1) return -EINVAL;

        /* initialise the system data */
        if ((ca = (struct dvb_ca_private*) kmalloc(sizeof(struct dvb_ca_private), GFP_KERNEL)) == NULL) {
                ret = -ENOMEM;
                goto error;
        }
        memset(ca, 0, sizeof(struct dvb_ca_private));
        ca->pub = pubca;
        ca->flags = flags;
        ca->slot_count = slot_count;
        if ((ca->slot_info = kmalloc(sizeof(struct dvb_ca_slot) * slot_count, GFP_KERNEL)) == NULL) {
                ret = -ENOMEM;
                goto error;
        }
        memset(ca->slot_info, 0, sizeof(struct dvb_ca_slot) * slot_count);
        init_waitqueue_head(&ca->wait_queue);
        ca->thread_pid = 0;
        init_waitqueue_head(&ca->thread_queue);
        ca->exit = 0;
        ca->open = 0;
        ca->wakeup = 0;
        ca->next_read_slot = 0;
        pubca->private = ca;

        /* register the DVB device */
        ret = dvb_register_device(dvb_adapter, &ca->dvbdev, &dvbdev_ca, ca, DVB_DEVICE_CA);
        if (ret) goto error;

        /* now initialise each slot */
        for(i=0; i< slot_count; i++) {
                memset(&ca->slot_info[i], 0, sizeof(struct dvb_ca_slot));
                ca->slot_info[i].slot_state = DVB_CA_SLOTSTATE_NONE;
                atomic_set(&ca->slot_info[i].camchange_count, 0);
                ca->slot_info[i].camchange_type = DVB_CA_EN50221_CAMCHANGE_REMOVED;
                init_MUTEX(&ca->slot_info[i].sem);
        }

        if (signal_pending(current)) {
                ret = -EINTR;
                goto error;
        }
        mb();

        /* create a kthread for monitoring this CA device */
        ret = kernel_thread (dvb_ca_en50221_thread, ca, 0);
        if (ret < 0) {
                printk("dvb_ca_init: failed to start kernel_thread (%d)\n", ret);
                goto error;
        }
        ca->thread_pid = ret;
        return 0;

error:
        if (ca != NULL) {
                if (ca->dvbdev != NULL) dvb_unregister_device(ca->dvbdev);
                if (ca->slot_info != NULL) kfree(ca->slot_info);
                kfree(ca);
        }
        pubca->private = NULL;
        return ret;
}



/**
 * Release a DVB CA EN50221 interface device.
 *
 * @param ca_dev The dvb_device_t instance for the CA device.
 * @param ca The associated dvb_ca instance.
 */
void dvb_ca_en50221_release(struct dvb_ca_en50221* pubca)
{
        struct dvb_ca_private* ca = (struct dvb_ca_private*) pubca->private;
        int i;

        dprintk ("%s\n", __FUNCTION__);

        /* shutdown the thread if there was one */
        if (ca->thread_pid) {
                if (kill_proc(ca->thread_pid, 0, 1) == -ESRCH) {
                        printk("dvb_ca_release: thread PID %d already died\n", ca->thread_pid);
                } else {
                        ca->exit = 1;
                        mb();
                        dvb_ca_en50221_thread_wakeup(ca);
                        wait_event_interruptible(ca->thread_queue, ca->thread_pid == 0);
                }
        }

        for(i=0; i< ca->slot_count; i++) {
                dvb_ca_en50221_slot_shutdown(ca, i);
        }
        kfree(ca->slot_info);
        dvb_unregister_device(ca->dvbdev);
        kfree(ca);
        pubca->private = NULL;
}

MODULE_PARM(dvb_ca_en50221_debug,"i");

MODULE_PARM_DESC(dvb_ca_en50221_debug, "enable verbose debug messages");