dvb_ca_en50221.c

Linux dvb-ci apifor use as an example

	int status;
	u8 buf[HOST_LINK_BUF_SIZE];
	int i;

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

	/* check if we have space for a link buf in the rx_buffer */
	if (ebuf == NULL) {
		int buf_free;

		if (ca->slot_info[slot].rx_buffer.data == NULL) {
			status = -EIO;
			goto exit;
		}
		buf_free = dvb_ringbuffer_free(&ca->slot_info[slot].rx_buffer);

		if (buf_free < (ca->slot_info[slot].link_buf_size + DVB_RINGBUFFER_PKTHDRSIZE)) {
			status = -EAGAIN;
			goto exit;
		}
	}

	/* check if there is data available */
	if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0)
		goto exit;
	if (!(status & STATUSREG_DA)) {
		/* no data */
		status = 0;
		goto exit;
	}

	/* read the amount of data */
	if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_SIZE_HIGH)) < 0)
		goto exit;
	bytes_read = status << 8;
	if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_SIZE_LOW)) < 0)
		goto exit;
	bytes_read |= status;

	/* check it will fit */
	if (ebuf == NULL) {
		if (bytes_read > ca->slot_info[slot].link_buf_size) {
			printk("dvb_ca adapter %d: CAM tried to send a buffer larger than the link buffer size (%i > %i)!\n",
			       ca->dvbdev->adapter->num, bytes_read, ca->slot_info[slot].link_buf_size);
			ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
			status = -EIO;
			goto exit;
		}
		if (bytes_read < 2) {
			printk("dvb_ca adapter %d: CAM sent a buffer that was less than 2 bytes!\n",
			       ca->dvbdev->adapter->num);
			ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
			status = -EIO;
			goto exit;
		}
	} else {
		if (bytes_read > ecount) {
			printk("dvb_ca adapter %d: CAM tried to send a buffer larger than the ecount size!\n",
			       ca->dvbdev->adapter->num);
			status = -EIO;
			goto exit;
		}
	}

	/* fill the buffer */
	for (i = 0; i < bytes_read; i++) {
		/* read byte and check */
		if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_DATA)) < 0)
			goto exit;

		/* OK, store it in the buffer */
		buf[i] = status;
	}

	/* check for read error (RE should now be 0) */
	if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0)
		goto exit;
	if (status & STATUSREG_RE) {
		ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
		status = -EIO;
		goto exit;
	}

	/* OK, add it to the receive buffer, or copy into external buffer if supplied */
	if (ebuf == NULL) {
		if (ca->slot_info[slot].rx_buffer.data == NULL) {
			status = -EIO;
			goto exit;
		}
		dvb_ringbuffer_pkt_write(&ca->slot_info[slot].rx_buffer, buf, bytes_read);
	} else {
		memcpy(ebuf, buf, bytes_read);
	}

	dprintk("Received CA packet for slot %i connection id 0x%x last_frag:%i size:0x%x\n", slot,
		buf[0], (buf[1] & 0x80) == 0, bytes_read);

	/* wake up readers when a last_fragment is received */
	if ((buf[1] & 0x80) == 0x00) {
		wake_up_interruptible(&ca->wait_queue);
	}
	status = bytes_read;

exit:
	return status;
}


/**
 * This function talks to an EN50221 CAM control interface. It writes a buffer of data
 * to a CAM.
 *
 * @param ca CA instance.
 * @param slot Slot to write to.
 * @param ebuf The data in this buffer is treated as a complete link-level packet to
 * be written.
 * @param count Size of ebuf.
 *
 * @return Number of bytes written, or < 0 on error.
 */
static int dvb_ca_en50221_write_data(struct dvb_ca_private *ca, int slot, u8 * buf, int bytes_write)
{
	int status;
	int i;

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


	// sanity check
	if (bytes_write > ca->slot_info[slot].link_buf_size)
		return -EINVAL;

	/* check if interface is actually waiting for us to read from it, or if a read is in progress */
	if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0)
		goto exitnowrite;
	if (status & (STATUSREG_DA | STATUSREG_RE)) {
		status = -EAGAIN;
		goto exitnowrite;
	}

	/* OK, set HC bit */
	if ((status = ca->pub->write_cam_control(ca->pub, slot, CTRLIF_COMMAND,
						 IRQEN | CMDREG_HC)) != 0)
		goto exit;

	/* check if interface is still free */
	if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0)
		goto exit;
	if (!(status & STATUSREG_FR)) {
		/* it wasn't free => try again later */
		status = -EAGAIN;
		goto exit;
	}

	/* send the amount of data */
	if ((status = ca->pub->write_cam_control(ca->pub, slot, CTRLIF_SIZE_HIGH, bytes_write >> 8)) != 0)
		goto exit;
	if ((status = ca->pub->write_cam_control(ca->pub, slot, CTRLIF_SIZE_LOW,
						 bytes_write & 0xff)) != 0)
		goto exit;

	/* send the buffer */
	for (i = 0; i < bytes_write; i++) {
		if ((status = ca->pub->write_cam_control(ca->pub, slot, CTRLIF_DATA, buf[i])) != 0)
			goto exit;
	}

	/* check for write error (WE should now be 0) */
	if ((status = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS)) < 0)
		goto exit;
	if (status & STATUSREG_WE) {
		ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
		status = -EIO;
		goto exit;
	}
	status = bytes_write;

	dprintk("Wrote CA packet for slot %i, connection id 0x%x last_frag:%i size:0x%x\n", slot,
		buf[0], (buf[1] & 0x80) == 0, bytes_write);

exit:
	ca->pub->write_cam_control(ca->pub, slot, CTRLIF_COMMAND, IRQEN);

exitnowrite:
	return status;
}
EXPORT_SYMBOL(dvb_ca_en50221_camchange_irq);



/* ******************************************************************************** */
/* EN50221 higher level functions */


/**
 * A CAM has been removed => shut it down.
 *
 * @param ca CA instance.
 * @param slot Slot to shut down.
 */
static int dvb_ca_en50221_slot_shutdown(struct dvb_ca_private *ca, int slot)
{
	dprintk("%s\n", __FUNCTION__);

	ca->pub->slot_shutdown(ca->pub, slot);
	ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_NONE;

	/* need to wake up all processes to check if they're now
	   trying to write to a defunct CAM */
	wake_up_interruptible(&ca->wait_queue);

	dprintk("Slot %i shutdown\n", slot);

	/* success */
	return 0;
}
EXPORT_SYMBOL(dvb_ca_en50221_camready_irq);


/**
 * A CAMCHANGE IRQ has occurred.
 *
 * @param ca CA instance.
 * @param slot Slot concerned.
 * @param change_type One of the DVB_CA_CAMCHANGE_* values.
 */
void dvb_ca_en50221_camchange_irq(struct dvb_ca_en50221 *pubca, int slot, int change_type)
{
	struct dvb_ca_private *ca = pubca->private;

	dprintk("CAMCHANGE IRQ slot:%i change_type:%i\n", slot, change_type);

	switch (change_type) {
	case DVB_CA_EN50221_CAMCHANGE_REMOVED:
	case DVB_CA_EN50221_CAMCHANGE_INSERTED:
		break;

	default:
		return;
	}

	ca->slot_info[slot].camchange_type = change_type;
	atomic_inc(&ca->slot_info[slot].camchange_count);
	dvb_ca_en50221_thread_wakeup(ca);
}
EXPORT_SYMBOL(dvb_ca_en50221_frda_irq);


/**
 * A CAMREADY IRQ has occurred.
 *
 * @param ca CA instance.
 * @param slot Slot concerned.
 */
void dvb_ca_en50221_camready_irq(struct dvb_ca_en50221 *pubca, int slot)
{
	struct dvb_ca_private *ca = pubca->private;

	dprintk("CAMREADY IRQ slot:%i\n", slot);

	if (ca->slot_info[slot].slot_state == DVB_CA_SLOTSTATE_WAITREADY) {
		ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_VALIDATE;
		dvb_ca_en50221_thread_wakeup(ca);
	}
}


/**
 * An FR or DA IRQ has occurred.
 *
 * @param ca CA instance.
 * @param slot Slot concerned.
 */
void dvb_ca_en50221_frda_irq(struct dvb_ca_en50221 *pubca, int slot)
{
	struct dvb_ca_private *ca = pubca->private;
	int flags;

	dprintk("FR/DA IRQ slot:%i\n", slot);

	switch (ca->slot_info[slot].slot_state) {
	case DVB_CA_SLOTSTATE_LINKINIT:
		flags = ca->pub->read_cam_control(pubca, slot, CTRLIF_STATUS);
		if (flags & STATUSREG_DA) {
			dprintk("CAM supports DA IRQ\n");
			ca->slot_info[slot].da_irq_supported = 1;
		}
		break;

	case DVB_CA_SLOTSTATE_RUNNING:
		if (ca->open)
			dvb_ca_en50221_thread_wakeup(ca);
		break;
	}
}



/* ******************************************************************************** */
/* EN50221 thread functions */

/**
 * Wake up the DVB CA thread
 *
 * @param ca CA instance.
 */
static void dvb_ca_en50221_thread_wakeup(struct dvb_ca_private *ca)
{

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

	ca->wakeup = 1;
	mb();
	wake_up_interruptible(&ca->thread_queue);
}

/**
 * Used by the CA thread to determine if an early wakeup is necessary
 *
 * @param ca CA instance.
 */
static int dvb_ca_en50221_thread_should_wakeup(struct dvb_ca_private *ca)
{
	if (ca->wakeup) {
		ca->wakeup = 0;
		return 1;
	}
	if (ca->exit)
		return 1;

	return 0;
}


/**
 * Update the delay used by the thread.
 *
 * @param ca CA instance.
 */
static void dvb_ca_en50221_thread_update_delay(struct dvb_ca_private *ca)
{
	int delay;
	int curdelay = 100000000;
	int slot;

	for (slot = 0; slot < ca->slot_count; slot++) {
		switch (ca->slot_info[slot].slot_state) {
		default:
		case DVB_CA_SLOTSTATE_NONE:
		case DVB_CA_SLOTSTATE_INVALID:
			delay = HZ * 60;
			if (!(ca->flags & DVB_CA_EN50221_FLAG_IRQ_CAMCHANGE)) {
				delay = HZ / 10;
			}
			break;

		case DVB_CA_SLOTSTATE_UNINITIALISED:
		case DVB_CA_SLOTSTATE_WAITREADY:
		case DVB_CA_SLOTSTATE_VALIDATE:
		case DVB_CA_SLOTSTATE_WAITFR:
		case DVB_CA_SLOTSTATE_LINKINIT:
			delay = HZ / 10;
			break;

		case DVB_CA_SLOTSTATE_RUNNING:
			delay = HZ * 60;
			if (!(ca->flags & DVB_CA_EN50221_FLAG_IRQ_CAMCHANGE)) {
				delay = HZ / 10;
			}
			if (ca->open) {
				if ((!ca->slot_info[slot].da_irq_supported) ||
				    (!(ca->flags & DVB_CA_EN50221_FLAG_IRQ_DA))) {
					delay = HZ / 10;
				}
			}
			break;
		}

		if (delay < curdelay)
			curdelay = delay;
	}

	ca->delay = curdelay;
}



/**
 * Kernel thread which monitors CA slots for CAM changes, and performs data transfers.
 */
static int dvb_ca_en50221_thread(void *data)
{
	struct dvb_ca_private *ca = data;
	char name[15];
	int slot;
	int flags;
	int status;
	int pktcount;
	void *rxbuf;

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

	/* setup kernel thread */
	snprintf(name, sizeof(name), "kdvb-ca-%i:%i", ca->dvbdev->adapter->num, ca->dvbdev->id);

	lock_kernel();
	daemonize(name);
	sigfillset(&current->blocked);
	unlock_kernel();

	/* choose the correct initial delay */
	dvb_ca_en50221_thread_update_delay(ca);

	/* main loop */
	while (!ca->exit) {
		/* sleep for a bit */
		if (!ca->wakeup) {
			flags = wait_event_interruptible_timeout(ca->thread_queue,
								 dvb_ca_en50221_thread_should_wakeup(ca),
								 ca->delay);
			if ((flags == -ERESTARTSYS) || ca->exit) {
				/* got signal or quitting */
				break;
			}
		}
		ca->wakeup = 0;

		/* go through all the slots processing them */
		for (slot = 0; slot < ca->slot_count; slot++) {

			// check the cam status + deal with CAMCHANGEs
			while (dvb_ca_en50221_check_camstatus(ca, slot)) {
				/* clear down an old CI slot if necessary */
				if (ca->slot_info[slot].slot_state != DVB_CA_SLOTSTATE_NONE)
					dvb_ca_en50221_slot_shutdown(ca, slot);

				/* if a CAM is NOW present, initialise it */
				if (ca->slot_info[slot].camchange_type == DVB_CA_EN50221_CAMCHANGE_INSERTED) {
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_UNINITIALISED;
				}

				/* we've handled one CAMCHANGE */
				dvb_ca_en50221_thread_update_delay(ca);
				atomic_dec(&ca->slot_info[slot].camchange_count);
			}

			// CAM state machine
			switch (ca->slot_info[slot].slot_state) {
			case DVB_CA_SLOTSTATE_NONE:
			case DVB_CA_SLOTSTATE_INVALID:
				// no action needed
				break;

			case DVB_CA_SLOTSTATE_UNINITIALISED:
				ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_WAITREADY;
				ca->pub->slot_reset(ca->pub, slot);
				ca->slot_info[slot].timeout = jiffies + (INIT_TIMEOUT_SECS * HZ);
				break;

			case DVB_CA_SLOTSTATE_WAITREADY:
				if (time_after(jiffies, ca->slot_info[slot].timeout)) {
					printk("dvb_ca adaptor %d: PC card did not respond :(\n",
					       ca->dvbdev->adapter->num);
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID;
					dvb_ca_en50221_thread_update_delay(ca);
					break;
				}
				// no other action needed; will automatically change state when ready
				break;

			case DVB_CA_SLOTSTATE_VALIDATE:
				if (dvb_ca_en50221_parse_attributes(ca, slot) != 0) {
					/* we need this extra check for annoying interfaces like the budget-av */
					if ((!(ca->flags & DVB_CA_EN50221_FLAG_IRQ_CAMCHANGE)) &&
					    (ca->pub->poll_slot_status)) {
						int status = ca->pub->poll_slot_status(ca->pub, slot, 0);
						if (!(status & DVB_CA_EN50221_POLL_CAM_PRESENT)) {
							ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_NONE;
							dvb_ca_en50221_thread_update_delay(ca);
							break;
						}
					}

					printk("dvb_ca adapter %d: Invalid PC card inserted :(\n",
					       ca->dvbdev->adapter->num);
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID;
					dvb_ca_en50221_thread_update_delay(ca);
					break;
				}
				if (dvb_ca_en50221_set_configoption(ca, slot) != 0) {
					printk("dvb_ca adapter %d: Unable to initialise CAM :(\n",
					       ca->dvbdev->adapter->num);
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID;
					dvb_ca_en50221_thread_update_delay(ca);
					break;
				}
				if (ca->pub->write_cam_control(ca->pub, slot,
							       CTRLIF_COMMAND, CMDREG_RS) != 0) {
					printk("dvb_ca adapter %d: Unable to reset CAM IF\n",
					       ca->dvbdev->adapter->num);
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID;
					dvb_ca_en50221_thread_update_delay(ca);
					break;
				}
				dprintk("DVB CAM validated successfully\n");

				ca->slot_info[slot].timeout = jiffies + (INIT_TIMEOUT_SECS * HZ);
				ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_WAITFR;
				ca->wakeup = 1;
				break;

			case DVB_CA_SLOTSTATE_WAITFR:
				if (time_after(jiffies, ca->slot_info[slot].timeout)) {
					printk("dvb_ca adapter %d: DVB CAM did not respond :(\n",
					       ca->dvbdev->adapter->num);
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID;
					dvb_ca_en50221_thread_update_delay(ca);
					break;
				}

				flags = ca->pub->read_cam_control(ca->pub, slot, CTRLIF_STATUS);
				if (flags & STATUSREG_FR) {
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_LINKINIT;
					ca->wakeup = 1;
				}
				break;

			case DVB_CA_SLOTSTATE_LINKINIT:
				if (dvb_ca_en50221_link_init(ca, slot) != 0) {
					/* we need this extra check for annoying interfaces like the budget-av */
					if ((!(ca->flags & DVB_CA_EN50221_FLAG_IRQ_CAMCHANGE)) &&
					    (ca->pub->poll_slot_status)) {
						int status = ca->pub->poll_slot_status(ca->pub, slot, 0);
						if (!(status & DVB_CA_EN50221_POLL_CAM_PRESENT)) {
							ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_NONE;
							dvb_ca_en50221_thread_update_delay(ca);
							break;
						}
					}

					printk("dvb_ca adapter %d: DVB CAM link initialisation failed :(\n", ca->dvbdev->adapter->num);
					ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID;
					dvb_ca_en50221_thread_update_delay(ca);
					break;
				}

				if (ca->slot_info[slot].rx_buffer.data == NULL) {
					rxbuf = vmalloc(RX_BUFFER_SIZE);
					if (rxbuf == NULL) {
						printk("dvb_ca adapter %d: Unable to allocate CAM rx buffer :(\n", ca->dvbdev->adapter->num);
						ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_INVALID;
						dvb_ca_en50221_thread_update_delay(ca);
						break;
					}
					dvb_ringbuffer_init(&ca->slot_info[slot].rx_buffer, rxbuf, RX_BUFFER_SIZE);
				}

				ca->pub->slot_ts_enable(ca->pub, slot);
				ca->slot_info[slot].slot_state = DVB_CA_SLOTSTATE_RUNNING;
				dvb_ca_en50221_thread_update_delay(ca);
				printk("dvb_ca adapter %d: DVB CAM detected and initialised successfully\n", ca->dvbdev->adapter->num);
				break;

			case DVB_CA_SLOTSTATE_RUNNING:
				if (!ca->open)
					continue;

				// poll slots for data
				pktcount = 0;
				while ((status = dvb_ca_en50221_read_data(ca, slot, NULL, 0)) > 0) {
					if (!ca->open)
						break;

					/* if a CAMCHANGE occurred at some point, do not do any more processing of this slot */
					if (dvb_ca_en50221_check_camstatus(ca, slot)) {
						// we dont want to sleep on the next iteration so we can handle the cam change
						ca->wakeup = 1;
						break;
					}

					/* check if we've hit our limit this time */
					if (++pktcount >= MAX_RX_PACKETS_PER_ITERATION) {
						// dont sleep; there is likely to be more data to read
						ca->wakeup = 1;
						break;
					}
				}
				break;
			}
		}
	}