via-maciisi.c

linux 内核源代码

	}
	if (maciisi_state == idle)
	{
		i = maciisi_start();
		if(i != 0)
		{
			local_irq_restore(flags);
			return i;
		}
	}
	else
	{
#ifdef DEBUG_MACIISI_ADB
		printk(KERN_DEBUG "maciisi_write: would start, but state is %d\n", maciisi_state);
#endif
		local_irq_restore(flags);
		return -EBUSY;
	}

	local_irq_restore(flags);

	return 0;
}

static int
maciisi_start(void)
{
	struct adb_request* req;
	int status;

#ifdef DEBUG_MACIISI_ADB
	status = via[B] & (TIP | TREQ);

	printk(KERN_DEBUG "maciisi_start called, state=%d, status=%x, ifr=%x\n", maciisi_state, status, via[IFR]);
#endif

	if (maciisi_state != idle) {
		/* shouldn't happen */
		printk(KERN_ERR "maciisi_start: maciisi_start called when driver busy!\n");
		return -EBUSY;
	}

	req = current_req;
	if (req == NULL)
		return -EINVAL;

	status = via[B] & (TIP|TREQ);
	if (!(status & TREQ)) {
#ifdef DEBUG_MACIISI_ADB
		printk(KERN_DEBUG "maciisi_start: bus busy - aborting\n");
#endif
		return -EBUSY;
	}

	/* Okay, send */
#ifdef DEBUG_MACIISI_ADB
	printk(KERN_DEBUG "maciisi_start: sending\n");
#endif
	/* Set state to active */
	via[B] |= TIP;
	/* ACK off */
	via[B] &= ~TACK;
	/* Delay */
	udelay(ADB_DELAY);
	/* Shift out and send */
	via[ACR] |= SR_OUT;
	via[SR] = req->data[0];
	data_index = 1;
	/* ACK on */
	via[B] |= TACK;
	maciisi_state = sending;

	return 0;
}

void
maciisi_poll(void)
{
	unsigned long flags;

	local_irq_save(flags);
	if (via[IFR] & SR_INT) {
		maciisi_interrupt(0, NULL);
	}
	else /* avoid calling this function too quickly in a loop */
		udelay(ADB_DELAY);

	local_irq_restore(flags);
}

/* Shift register interrupt - this is *supposed* to mean that the
   register is either full or empty. In practice, I have no idea what
   it means :( */
static irqreturn_t
maciisi_interrupt(int irq, void* arg)
{
	int status;
	struct adb_request *req;
#ifdef DEBUG_MACIISI_ADB
	static int dump_reply = 0;
#endif
	int i;
	unsigned long flags;

	local_irq_save(flags);

	status = via[B] & (TIP|TREQ);
#ifdef DEBUG_MACIISI_ADB
	printk(KERN_DEBUG "state %d status %x ifr %x\n", maciisi_state, status, via[IFR]);
#endif

	if (!(via[IFR] & SR_INT)) {
		/* Shouldn't happen, we hope */
		printk(KERN_ERR "maciisi_interrupt: called without interrupt flag set\n");
		local_irq_restore(flags);
		return IRQ_NONE;
	}

	/* Clear the interrupt */
	/* via[IFR] = SR_INT; */

 switch_start:
	switch (maciisi_state) {
	case idle:
		if (status & TIP)
			printk(KERN_ERR "maciisi_interrupt: state is idle but TIP asserted!\n");

		if(!reading_reply)
			udelay(ADB_DELAY);
		/* Shift in */
		via[ACR] &= ~SR_OUT;
 		/* Signal start of frame */
		via[B] |= TIP;
		/* Clear the interrupt (throw this value on the floor, it's useless) */
		tmp = via[SR];
		/* ACK adb chip, high-low */
		via[B] |= TACK;
		udelay(ADB_DELAY);
		via[B] &= ~TACK;
		reply_len = 0;
		maciisi_state = reading;
		if (reading_reply) {
			reply_ptr = current_req->reply;
		} else {
			reply_ptr = maciisi_rbuf;
		}
		break;

	case sending:
		/* via[SR]; */
		/* Set ACK off */
		via[B] &= ~TACK;
		req = current_req;

		if (!(status & TREQ)) {
			/* collision */
			printk(KERN_ERR "maciisi_interrupt: send collision\n");
			/* Set idle and input */
			via[ACR] &= ~SR_OUT;
			tmp = via[SR];
			via[B] &= ~TIP;
			/* Must re-send */
			reading_reply = 0;
			reply_len = 0;
			maciisi_state = idle;
			udelay(ADB_DELAY);
			/* process this now, because the IFR has been cleared */
			goto switch_start;
		}

		udelay(ADB_DELAY);

		if (data_index >= req->nbytes) {
			/* Sent the whole packet, put the bus back in idle state */
			/* Shift in, we are about to read a reply (hopefully) */
			via[ACR] &= ~SR_OUT;
			tmp = via[SR];
			/* End of frame */
			via[B] &= ~TIP;
			req->sent = 1;
			maciisi_state = idle;
			if (req->reply_expected) {
				/* Note: only set this once we've
                                   successfully sent the packet */
				reading_reply = 1;
			} else {
				current_req = req->next;
				if (req->done)
					(*req->done)(req);
				/* Do any queued requests now */
				i = maciisi_start();
				if(i == 0 && need_sync) {
					/* Packet needs to be synced */
					maciisi_sync(current_req);
				}
				if(i != -EBUSY)
					need_sync = 0;
			}
		} else {
			/* Sending more stuff */
			/* Shift out */
			via[ACR] |= SR_OUT;
			/* Write */
			via[SR] = req->data[data_index++];
			/* Signal 'byte ready' */
			via[B] |= TACK;
		}
		break;

	case reading:
		/* Shift in */
		/* via[ACR] &= ~SR_OUT; */ /* Not in 2.2 */
		if (reply_len++ > 16) {
			printk(KERN_ERR "maciisi_interrupt: reply too long, aborting read\n");
			via[B] |= TACK;
			udelay(ADB_DELAY);
			via[B] &= ~(TACK|TIP);
			maciisi_state = idle;
			i = maciisi_start();
			if(i == 0 && need_sync) {
				/* Packet needs to be synced */
				maciisi_sync(current_req);
			}
			if(i != -EBUSY)
				need_sync = 0;
			break;
		}
		/* Read data */
		*reply_ptr++ = via[SR];
		status = via[B] & (TIP|TREQ);
		/* ACK on/off */
		via[B] |= TACK;
		udelay(ADB_DELAY);
		via[B] &= ~TACK;	
		if (!(status & TREQ))
			break; /* more stuff to deal with */
		
		/* end of frame */
		via[B] &= ~TIP;
		tmp = via[SR]; /* That's what happens in 2.2 */
		udelay(ADB_DELAY); /* Give controller time to recover */

		/* end of packet, deal with it */
		if (reading_reply) {
			req = current_req;
			req->reply_len = reply_ptr - req->reply;
			if (req->data[0] == ADB_PACKET) {
				/* Have to adjust the reply from ADB commands */
				if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
					/* the 0x2 bit indicates no response */
					req->reply_len = 0;
				} else {
					/* leave just the command and result bytes in the reply */
					req->reply_len -= 2;
					memmove(req->reply, req->reply + 2, req->reply_len);
				}
			}
#ifdef DEBUG_MACIISI_ADB
			if (dump_reply) {
				int i;
				printk(KERN_DEBUG "maciisi_interrupt: reply is ");
				for (i = 0; i < req->reply_len; ++i)
					printk(" %.2x", req->reply[i]);
				printk("\n");
			}
#endif
			req->complete = 1;
			current_req = req->next;
			if (req->done)
				(*req->done)(req);
			/* Obviously, we got it */
			reading_reply = 0;
		} else {
			maciisi_input(maciisi_rbuf, reply_ptr - maciisi_rbuf);
		}
		maciisi_state = idle;
		status = via[B] & (TIP|TREQ);
		if (!(status & TREQ)) {
			/* Timeout?! More likely, another packet coming in already */
#ifdef DEBUG_MACIISI_ADB
			printk(KERN_DEBUG "extra data after packet: status %x ifr %x\n",
			       status, via[IFR]);
#endif
#if 0
			udelay(ADB_DELAY);
			via[B] |= TIP;

			maciisi_state = reading;
			reading_reply = 0;
			reply_ptr = maciisi_rbuf;
#else
			/* Process the packet now */
			reading_reply = 0;
			goto switch_start;
#endif
			/* We used to do this... but the controller might actually have data for us */
			/* maciisi_stfu(); */
		}
		else {
			/* Do any queued requests now if possible */
			i = maciisi_start();
			if(i == 0 && need_sync) {
				/* Packet needs to be synced */
				maciisi_sync(current_req);
			}
			if(i != -EBUSY)
				need_sync = 0;
		}
		break;

	default:
		printk("maciisi_interrupt: unknown maciisi_state %d?\n", maciisi_state);
	}
	local_irq_restore(flags);
	return IRQ_HANDLED;
}

static void
maciisi_input(unsigned char *buf, int nb)
{
#ifdef DEBUG_MACIISI_ADB
    int i;
#endif

    switch (buf[0]) {
    case ADB_PACKET:
	    adb_input(buf+2, nb-2, buf[1] & 0x40);
	    break;
    default:
#ifdef DEBUG_MACIISI_ADB
	    printk(KERN_DEBUG "data from IIsi ADB (%d bytes):", nb);
	    for (i = 0; i < nb; ++i)
		    printk(" %.2x", buf[i]);
	    printk("\n");
#endif
	    break;
    }
}