synclink_cs.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

	
	info->bh_running = 1;

	while((action = bh_action(info)) != 0) {
	
		/* Process work item */
		if ( debug_level >= DEBUG_LEVEL_BH )
			printk( "%s(%d):bh_handler() work item action=%d\n",
				__FILE__,__LINE__,action);

		switch (action) {
		
		case BH_RECEIVE:
			while(rx_get_frame(info));
			break;
		case BH_TRANSMIT:
			bh_transmit(info);
			break;
		case BH_STATUS:
			bh_status(info);
			break;
		default:
			/* unknown work item ID */
			printk("Unknown work item ID=%08X!\n", action);
			break;
		}
	}

	if (debug_level >= DEBUG_LEVEL_BH)
		printk( "%s(%d):bh_handler(%s) exit\n",
			__FILE__,__LINE__,info->device_name);
}

void bh_transmit(MGSLPC_INFO *info)
{
	struct tty_struct *tty = info->tty;
	if (debug_level >= DEBUG_LEVEL_BH)
		printk("bh_transmit() entry on %s\n", info->device_name);

	if (tty) {
		if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
		    tty->ldisc.write_wakeup) {
			if ( debug_level >= DEBUG_LEVEL_BH )
				printk( "%s(%d):calling ldisc.write_wakeup on %s\n",
					__FILE__,__LINE__,info->device_name);
			(tty->ldisc.write_wakeup)(tty);
		}
		wake_up_interruptible(&tty->write_wait);
	}
}

void bh_status(MGSLPC_INFO *info)
{
	info->ri_chkcount = 0;
	info->dsr_chkcount = 0;
	info->dcd_chkcount = 0;
	info->cts_chkcount = 0;
}

/* eom: non-zero = end of frame */ 
void rx_ready_hdlc(MGSLPC_INFO *info, int eom) 
{
	unsigned char data[2];
	unsigned char fifo_count, read_count, i;
	RXBUF *buf = (RXBUF*)(info->rx_buf + (info->rx_put * info->rx_buf_size));

	if (debug_level >= DEBUG_LEVEL_ISR)
		printk("%s(%d):rx_ready_hdlc(eom=%d)\n",__FILE__,__LINE__,eom);
	
	if (!info->rx_enabled)
		return;

	if (info->rx_frame_count >= info->rx_buf_count) {
		/* no more free buffers */
		issue_command(info, CHA, CMD_RXRESET);
		info->pending_bh |= BH_RECEIVE;
		info->rx_overflow = 1;
		info->icount.buf_overrun++;
		return;
	}

	if (eom) {
		/* end of frame, get FIFO count from RBCL register */ 
		if (!(fifo_count = (unsigned char)(read_reg(info, CHA+RBCL) & 0x1f)))
			fifo_count = 32;
	} else
		fifo_count = 32;
	
	do {
		if (fifo_count == 1) {
			read_count = 1;
			data[0] = read_reg(info, CHA + RXFIFO);
		} else {
			read_count = 2;
			*((unsigned short *) data) = read_reg16(info, CHA + RXFIFO);
		}
		fifo_count -= read_count;
		if (!fifo_count && eom)
			buf->status = data[--read_count];

		for (i = 0; i < read_count; i++) {
			if (buf->count >= info->max_frame_size) {
				/* frame too large, reset receiver and reset current buffer */
				issue_command(info, CHA, CMD_RXRESET);
				buf->count = 0;
				return;
			}
			*(buf->data + buf->count) = data[i];
			buf->count++;
		}
	} while (fifo_count);

	if (eom) {
		info->pending_bh |= BH_RECEIVE;
		info->rx_frame_count++;
		info->rx_put++;
		if (info->rx_put >= info->rx_buf_count)
			info->rx_put = 0;
	}
	issue_command(info, CHA, CMD_RXFIFO);
}

void rx_ready_async(MGSLPC_INFO *info, int tcd) 
{
	unsigned char data, status;
	int fifo_count;
 	struct tty_struct *tty = info->tty;
 	struct mgsl_icount *icount = &info->icount;

	if (tcd) {
		/* early termination, get FIFO count from RBCL register */ 
		fifo_count = (unsigned char)(read_reg(info, CHA+RBCL) & 0x1f);

		/* Zero fifo count could mean 0 or 32 bytes available.
		 * If BIT5 of STAR is set then at least 1 byte is available.
		 */
		if (!fifo_count && (read_reg(info,CHA+STAR) & BIT5))
			fifo_count = 32;
	} else
		fifo_count = 32;
	
	/* Flush received async data to receive data buffer. */ 
	while (fifo_count) {
		data   = read_reg(info, CHA + RXFIFO);
		status = read_reg(info, CHA + RXFIFO);
		fifo_count -= 2;

		if (tty->flip.count >= TTY_FLIPBUF_SIZE)
			break;
			
		*tty->flip.char_buf_ptr = data;
		icount->rx++;
		
		*tty->flip.flag_buf_ptr = 0;

		// if no frameing/crc error then save data
		// BIT7:parity error
		// BIT6:framing error

		if (status & (BIT7 + BIT6)) {
			if (status & BIT7) 
				icount->parity++;
			else
				icount->frame++;

			/* discard char if tty control flags say so */
			if (status & info->ignore_status_mask)
				continue;
				
			status &= info->read_status_mask;

			if (status & BIT7)
				*tty->flip.flag_buf_ptr = TTY_PARITY;
			else if (status & BIT6)
				*tty->flip.flag_buf_ptr = TTY_FRAME;
		}
		
		tty->flip.flag_buf_ptr++;
		tty->flip.char_buf_ptr++;
		tty->flip.count++;
	}
	issue_command(info, CHA, CMD_RXFIFO);

	if (debug_level >= DEBUG_LEVEL_ISR) {
		printk("%s(%d):rx_ready_async count=%d\n",
			__FILE__,__LINE__,tty->flip.count);
		printk("%s(%d):rx=%d brk=%d parity=%d frame=%d overrun=%d\n",
			__FILE__,__LINE__,icount->rx,icount->brk,
			icount->parity,icount->frame,icount->overrun);
	}
			
	if (tty->flip.count)
		tty_flip_buffer_push(tty);
}


void tx_done(MGSLPC_INFO *info) 
{
	if (!info->tx_active)
		return;
			
	info->tx_active = 0;
	info->tx_aborting = 0;

	if (info->params.mode == MGSL_MODE_ASYNC)
		return;

	info->tx_count = info->tx_put = info->tx_get = 0;
	del_timer(&info->tx_timer);	
	
	if (info->drop_rts_on_tx_done) {
		get_signals(info);
		if (info->serial_signals & SerialSignal_RTS) {
			info->serial_signals &= ~SerialSignal_RTS;
			set_signals(info);
		}
		info->drop_rts_on_tx_done = 0;
	}

#ifdef CONFIG_SYNCLINK_SYNCPPP	
	if (info->netcount)
		mgslpc_sppp_tx_done(info);
	else 
#endif
	{
		if (info->tty->stopped || info->tty->hw_stopped) {
			tx_stop(info);
			return;
		}
		info->pending_bh |= BH_TRANSMIT;
	}
}

void tx_ready(MGSLPC_INFO *info) 
{
	unsigned char fifo_count = 32;
	int c;

	if (debug_level >= DEBUG_LEVEL_ISR)
		printk("%s(%d):tx_ready(%s)\n", __FILE__,__LINE__,info->device_name);

	if (info->params.mode == MGSL_MODE_HDLC) {
		if (!info->tx_active)
			return;
	} else {
		if (info->tty->stopped || info->tty->hw_stopped) {
			tx_stop(info);
			return;
		}
		if (!info->tx_count)
			info->tx_active = 0;
	}

	if (!info->tx_count)
		return;

	while (info->tx_count && fifo_count) {
		c = MIN(2, MIN(fifo_count, MIN(info->tx_count, TXBUFSIZE - info->tx_get)));
		
		if (c == 1) {
			write_reg(info, CHA + TXFIFO, *(info->tx_buf + info->tx_get));
		} else {
			write_reg16(info, CHA + TXFIFO,
					  *((unsigned short*)(info->tx_buf + info->tx_get)));
		}
		info->tx_count -= c;
		info->tx_get = (info->tx_get + c) & (TXBUFSIZE - 1);
		fifo_count -= c;
	}

	if (info->params.mode == MGSL_MODE_ASYNC) {
		if (info->tx_count < WAKEUP_CHARS)
			info->pending_bh |= BH_TRANSMIT;
		issue_command(info, CHA, CMD_TXFIFO);
	} else {
		if (info->tx_count)
			issue_command(info, CHA, CMD_TXFIFO);
		else
			issue_command(info, CHA, CMD_TXFIFO + CMD_TXEOM);
	}
}

void cts_change(MGSLPC_INFO *info) 
{
	get_signals(info);
	if ((info->cts_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
		irq_disable(info, CHB, IRQ_CTS);
	info->icount.cts++;
	if (info->serial_signals & SerialSignal_CTS)
		info->input_signal_events.cts_up++;
	else
		info->input_signal_events.cts_down++;
	wake_up_interruptible(&info->status_event_wait_q);
	wake_up_interruptible(&info->event_wait_q);

	if (info->flags & ASYNC_CTS_FLOW) {
		if (info->tty->hw_stopped) {
			if (info->serial_signals & SerialSignal_CTS) {
				if (debug_level >= DEBUG_LEVEL_ISR)
					printk("CTS tx start...");
				if (info->tty)
					info->tty->hw_stopped = 0;
				tx_start(info);
				info->pending_bh |= BH_TRANSMIT;
				return;
			}
		} else {
			if (!(info->serial_signals & SerialSignal_CTS)) {
				if (debug_level >= DEBUG_LEVEL_ISR)
					printk("CTS tx stop...");
				if (info->tty)
					info->tty->hw_stopped = 1;
				tx_stop(info);
			}
		}
	}
	info->pending_bh |= BH_STATUS;
}

void dcd_change(MGSLPC_INFO *info) 
{
	get_signals(info);
	if ((info->dcd_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
		irq_disable(info, CHB, IRQ_DCD);
	info->icount.dcd++;
	if (info->serial_signals & SerialSignal_DCD) {
		info->input_signal_events.dcd_up++;
#ifdef CONFIG_SYNCLINK_SYNCPPP	
		if (info->netcount)
			sppp_reopen(info->netdev);
#endif
	}
	else
		info->input_signal_events.dcd_down++;
	wake_up_interruptible(&info->status_event_wait_q);
	wake_up_interruptible(&info->event_wait_q);

	if (info->flags & ASYNC_CHECK_CD) {
		if (debug_level >= DEBUG_LEVEL_ISR)
			printk("%s CD now %s...", info->device_name,
			       (info->serial_signals & SerialSignal_DCD) ? "on" : "off");
		if (info->serial_signals & SerialSignal_DCD)
			wake_up_interruptible(&info->open_wait);
		else if (!(info->flags & (ASYNC_CALLOUT_ACTIVE | ASYNC_CALLOUT_NOHUP))) {
			if (debug_level >= DEBUG_LEVEL_ISR)
				printk("doing serial hangup...");
			if (info->tty)
				tty_hangup(info->tty);
		}
	}
	info->pending_bh |= BH_STATUS;
}

void dsr_change(MGSLPC_INFO *info) 
{
	get_signals(info);
	if ((info->dsr_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
		port_irq_disable(info, PVR_DSR);
	info->icount.dsr++;
	if (info->serial_signals & SerialSignal_DSR)
		info->input_signal_events.dsr_up++;
	else
		info->input_signal_events.dsr_down++;
	wake_up_interruptible(&info->status_event_wait_q);
	wake_up_interruptible(&info->event_wait_q);
	info->pending_bh |= BH_STATUS;
}

void ri_change(MGSLPC_INFO *info) 
{
	get_signals(info);
	if ((info->ri_chkcount)++ >= IO_PIN_SHUTDOWN_LIMIT)
		port_irq_disable(info, PVR_RI);
	info->icount.rng++;
	if (info->serial_signals & SerialSignal_RI)
		info->input_signal_events.ri_up++;
	else
		info->input_signal_events.ri_down++;
	wake_up_interruptible(&info->status_event_wait_q);
	wake_up_interruptible(&info->event_wait_q);
	info->pending_bh |= BH_STATUS;
}

/* Interrupt service routine entry point.
 * 	
 * Arguments:
 * 
 * irq     interrupt number that caused interrupt
 * dev_id  device ID supplied during interrupt registration
 * regs    interrupted processor context
 */
static void mgslpc_isr(int irq, void *dev_id, struct pt_regs * regs)
{
	MGSLPC_INFO * info = (MGSLPC_INFO *)dev_id;
	unsigned short isr;
	unsigned char gis, pis;
	int count=0;

	if (debug_level >= DEBUG_LEVEL_ISR)	
		printk("mgslpc_isr(%d) entry.\n", irq);
	if (!info)
		return;
		
	if (!(info->link.state & DEV_CONFIG))
		return;

	spin_lock(&info->lock);

	while ((gis = read_reg(info, CHA + GIS))) {
		if (debug_level >= DEBUG_LEVEL_ISR)	
			printk("mgslpc_isr %s gis=%04X\n", info->device_name,gis);

		if ((gis & 0x70) || count > 1000) {
			printk("synclink_cs:hardware failed or ejected\n");
			break;
		}
		count++;

		if (gis & (BIT1 + BIT0)) {
			isr = read_reg16(info, CHB + ISR);
			if (isr & IRQ_DCD)
				dcd_change(info);
			if (isr & IRQ_CTS)
				cts_change(info);
		}
		if (gis & (BIT3 + BIT2))
		{
			isr = read_reg16(info, CHA + ISR);
			if (isr & IRQ_TIMER) {
				info->irq_occurred = 1;
				irq_disable(info, CHA, IRQ_TIMER);
			}

			/* receive IRQs */ 
			if (isr & IRQ_EXITHUNT) {
				info->icount.exithunt++;
				wake_up_interruptible(&info->event_wait_q);
			}
			if (isr & IRQ_BREAK_ON) {
				info->icount.brk++;
				if (info->flags & ASYNC_SAK)
					do_SAK(info->tty);
			}
			if (isr & IRQ_RXTIME) {
				issue_command(info, CHA, CMD_RXFIFO_READ);
			}
			if (isr & (IRQ_RXEOM + IRQ_RXFIFO)) {
				if (info->params.mode == MGSL_MODE_HDLC)
					rx_ready_hdlc(info, isr & IRQ_RXEOM); 
				else
					rx_ready_async(info, isr & IRQ_RXEOM);
			}

			/* transmit IRQs */ 
			if (isr & IRQ_UNDERRUN) {
				if (info->tx_aborting)
					info->icount.txabort++;
				else
					info->icount.txunder++;
				tx_done(info);
			}
			else if (isr & IRQ_ALLSENT) {
				info->icount.txok++;
				tx_done(info);
			}
			else if (isr & IRQ_TXFIFO)
				tx_ready(info);
		}
		if (gis & BIT7) {
			pis = read_reg(info, CHA + PIS);
			if (pis & BIT1)
				dsr_change(info);
			if (pis & BIT2)
				ri_change(info);
		}
	}
	
	/* Request bottom half processing if there's something 
	 * for it to do and the bh is not already running
	 */

	if (info->pending_bh && !info->bh_running && !info->bh_requested) {
		if ( debug_level >= DEBUG_LEVEL_ISR )	
			printk("%s(%d):%s queueing bh task.\n",
				__FILE__,__LINE__,info->device_name);
		queue_task(&info->task, &tq_immediate);
		mark_bh(IMMEDIATE_BH);
		info->bh_requested = 1;
	}

	spin_unlock(&info->lock);