serial.c

该文件是rt_linux

#endif
#endif
}

/* If this behaves as a modem, RI and CD is an output */
static inline void 
e100_ri_out(struct e100_serial *info, int set)
{
#ifndef CONFIG_SVINTO_SIM
	/* RI is active low */
	{
		unsigned char mask = (1 << e100_modem_pins[info->line].ri_bit);
		unsigned long flags;

		save_flags(flags);
		cli();
		*e100_modem_pins[info->line].shadow &= ~mask;
		*e100_modem_pins[info->line].shadow |= (set ? 0 : mask); 
		*e100_modem_pins[info->line].port = *e100_modem_pins[info->line].shadow;
		restore_flags(flags);
	}
#endif
}
static inline void 
e100_cd_out(struct e100_serial *info, int set)
{
#ifndef CONFIG_SVINTO_SIM
	/* CD is active low */
	{
		unsigned char mask = (1 << e100_modem_pins[info->line].cd_bit);
		unsigned long flags;

		save_flags(flags);
		cli();
		*e100_modem_pins[info->line].shadow &= ~mask;
		*e100_modem_pins[info->line].shadow |= (set ? 0 : mask); 
		*e100_modem_pins[info->line].port = *e100_modem_pins[info->line].shadow;
		restore_flags(flags);
	}
#endif
}

static inline void
e100_disable_rx(struct e100_serial *info)
{
#ifndef CONFIG_SVINTO_SIM
	/* disable the receiver */
	info->port[REG_REC_CTRL] =
		(info->rx_ctrl &= ~IO_MASK(R_SERIAL0_REC_CTRL, rec_enable));
#endif
}

static inline void 
e100_enable_rx(struct e100_serial *info)
{
#ifndef CONFIG_SVINTO_SIM
	/* enable the receiver */
	info->port[REG_REC_CTRL] =
		(info->rx_ctrl |= IO_MASK(R_SERIAL0_REC_CTRL, rec_enable));
#endif
}

/* the rx DMA uses both the dma_descr and the dma_eop interrupts */

static inline void
e100_disable_rxdma_irq(struct e100_serial *info) 
{
#ifdef SERIAL_DEBUG_INTR
	printk("rxdma_irq(%d): 0\n",info->line);
#endif
	*R_IRQ_MASK2_CLR = (info->irq << 2) | (info->irq << 3);
}

static inline void
e100_enable_rxdma_irq(struct e100_serial *info) 
{
#ifdef SERIAL_DEBUG_INTR
	printk("rxdma_irq(%d): 1\n",info->line);
#endif
	*R_IRQ_MASK2_SET = (info->irq << 2) | (info->irq << 3);
}

/* the tx DMA uses only dma_descr interrupt */

static inline void
e100_disable_txdma_irq(struct e100_serial *info) 
{
#ifdef SERIAL_DEBUG_INTR
	printk("txdma_irq(%d): 0\n",info->line);
#endif
	*R_IRQ_MASK2_CLR = info->irq;
}

static inline void
e100_enable_txdma_irq(struct e100_serial *info) 
{
#ifdef SERIAL_DEBUG_INTR
	printk("txdma_irq(%d): 1\n",info->line);
#endif
	*R_IRQ_MASK2_SET = info->irq;
}

#ifdef SERIAL_HANDLE_EARLY_ERRORS
/* in order to detect and fix errors on the first byte
   we have to use the serial interrupts as well. */

static inline void
e100_disable_serial_data_irq(struct e100_serial *info) 
{
#ifdef SERIAL_DEBUG_INTR
	printk("ser_irq(%d): 0\n",info->line);
#endif
	*R_IRQ_MASK1_CLR = (1U << (8+2*info->line));
}

static inline void
e100_enable_serial_data_irq(struct e100_serial *info) 
{
#ifdef SERIAL_DEBUG_INTR
	printk("ser_irq(%d): 1\n",info->line);
	printk("**** %d = %d\n",
	       (8+2*info->line),
	       (1U << (8+2*info->line)));
#endif
	*R_IRQ_MASK1_SET = (1U << (8+2*info->line));
}
#endif

#if defined(CONFIG_ETRAX_RS485)
/* Enable RS-485 mode on selected port. This is UGLY. */
static int
e100_enable_rs485(struct tty_struct *tty,struct rs485_control *r)
{
	struct e100_serial * info = (struct e100_serial *)tty->driver_data;

#if defined(CONFIG_ETRAX_RS485_ON_PA)	
	*R_PORT_PA_DATA = port_pa_data_shadow |= (1 << rs485_pa_bit);
#endif

	info->rs485.rts_on_send = 0x01 & r->rts_on_send;
	info->rs485.rts_after_sent = 0x01 & r->rts_after_sent;
	info->rs485.delay_rts_before_send = r->delay_rts_before_send;
	info->rs485.enabled = r->enabled;
/*	printk("rts: on send = %i, after = %i, enabled = %i",
		    info->rs485.rts_on_send,
		    info->rs485.rts_after_sent,
		    info->rs485.enabled
	);
*/		
	return 0;
}

static int
e100_write_rs485(struct tty_struct *tty, int from_user,
                 const unsigned char *buf, int count)
{
	struct e100_serial * info = (struct e100_serial *)tty->driver_data;
	int old_enabled = info->rs485.enabled;

	/* rs485 is always implicitly enabled if we're using the ioctl() 
	 * but it doesn't have to be set in the rs485_control
	 * (to be backward compatible with old apps)
	 * So we store, set and restore it.
	 */
	info->rs485.enabled = 1;
	/* rs_write now deals with RS485 if enabled */
	count = rs_write(tty, from_user, buf, count);
	info->rs485.enabled = old_enabled;
	return count;
}

#ifdef CONFIG_ETRAX_FAST_TIMER
/* Timer function to toggle RTS when using FAST_TIMER */
static void rs485_toggle_rts_timer_function(unsigned long data)
{
	struct e100_serial *info = (struct e100_serial *)data;

	fast_timers_rs485[info->line].function = NULL;
	e100_rts(info, info->rs485.rts_after_sent);
#if defined(CONFIG_ETRAX_RS485_DISABLE_RECEIVER)
	e100_enable_rx(info);
	e100_enable_rxdma_irq(info);
#endif
}
#endif
#endif /* CONFIG_ETRAX_RS485 */

/*
 * ------------------------------------------------------------
 * rs_stop() and rs_start()
 *
 * This routines are called before setting or resetting tty->stopped.
 * They enable or disable transmitter interrupts, as necessary.
 * ------------------------------------------------------------
 */

/* FIXME - when are these used and what is the purpose ? 
 * In rs_stop we probably just can block the transmit DMA ready irq
 * and in rs_start we re-enable it (and then the old one will come).
 */

static void 
rs_stop(struct tty_struct *tty)
{
}

static void 
rs_start(struct tty_struct *tty)
{
}

/*
 * ----------------------------------------------------------------------
 *
 * Here starts the interrupt handling routines.  All of the following
 * subroutines are declared as inline and are folded into
 * rs_interrupt().  They were separated out for readability's sake.
 *
 * Note: rs_interrupt() is a "fast" interrupt, which means that it
 * runs with interrupts turned off.  People who may want to modify
 * rs_interrupt() should try to keep the interrupt handler as fast as
 * possible.  After you are done making modifications, it is not a bad
 * idea to do:
 * 
 * gcc -S -DKERNEL -Wall -Wstrict-prototypes -O6 -fomit-frame-pointer serial.c
 *
 * and look at the resulting assemble code in serial.s.
 *
 * 				- Ted Ts'o ([e-mail]), 7-Mar-93
 * -----------------------------------------------------------------------
 */

/*
 * This routine is used by the interrupt handler to schedule
 * processing in the software interrupt portion of the driver.
 */
static _INLINE_ void 
rs_sched_event(struct e100_serial *info,
				    int event)
{
	info->event |= 1 << event;
	queue_task(&info->tqueue, &tq_serial);
	mark_bh(SERIAL_BH);
}

/* The output DMA channel is free - use it to send as many chars as possible
 * NOTES:
 *   We don't pay attention to info->x_char, which means if the TTY wants to
 *   use XON/XOFF it will set info->x_char but we won't send any X char!
 * 
 *   To implement this, we'd just start a DMA send of 1 byte pointing at a
 *   buffer containing the X char, and skip updating xmit. We'd also have to
 *   check if the last sent char was the X char when we enter this function
 *   the next time, to avoid updating xmit with the sent X value.
 */

static void 
transmit_chars(struct e100_serial *info)
{
	unsigned int c, sentl;
	struct etrax_dma_descr *descr;

#ifdef CONFIG_SVINTO_SIM
	/* This will output too little if tail is not 0 always since
	 * we don't reloop to send the other part. Anyway this SHOULD be a
	 * no-op - transmit_chars would never really be called during sim
	 * since rs_write does not write into the xmit buffer then.
	 */
	if (info->xmit.tail)
		printk("Error in serial.c:transmit_chars(), tail!=0\n");
	if (info->xmit.head != info->xmit.tail) {
		SIMCOUT(info->xmit.buf + info->xmit.tail,
			CIRC_CNT(info->xmit.head,
				 info->xmit.tail,
				 SERIAL_XMIT_SIZE));
		info->xmit.head = info->xmit.tail;  /* move back head */
		info->tr_running = 0;
	}
	return;
#endif
	/* acknowledge both dma_descr and dma_eop irq in R_DMA_CHx_CLR_INTR */
	*info->oclrintradr =
		IO_STATE(R_DMA_CH6_CLR_INTR, clr_descr, do) |
		IO_STATE(R_DMA_CH6_CLR_INTR, clr_eop, do);

#ifdef SERIAL_DEBUG_INTR
	if (info->line == SERIAL_DEBUG_LINE)
		printk("tc\n");
#endif
	if (!info->tr_running) {
		/* weirdo... we shouldn't get here! */
		printk("Achtung: transmit_chars with !tr_running\n");
		return;
	}

	descr = &info->tr_descr;

	/* first get the amount of bytes sent during the last DMA transfer,
	   and update xmit accordingly */

	/* if the stop bit was not set, all data has been sent */
	if (!(descr->status & d_stop)) {
		sentl = descr->sw_len;
	} else 
		/* otherwise we find the amount of data sent here */
		sentl = descr->hw_len;

	/* update stats */
	info->icount.tx += sentl;

	/* update xmit buffer */
	info->xmit.tail = (info->xmit.tail + sentl) & (SERIAL_XMIT_SIZE - 1);

	/* if there is only a few chars left in the buf, wake up the blocked
	   write if any */
	if (CIRC_CNT(info->xmit.head,
		     info->xmit.tail,
		     SERIAL_XMIT_SIZE) < WAKEUP_CHARS)
		rs_sched_event(info, RS_EVENT_WRITE_WAKEUP);

	/* find out the largest amount of consecutive bytes we want to send now */

	c = CIRC_CNT_TO_END(info->xmit.head, info->xmit.tail, SERIAL_XMIT_SIZE);

	if (c <= 0) {
		/* our job here is done, don't schedule any new DMA transfer */
		info->tr_running = 0;

#if defined(CONFIG_ETRAX_RS485) && defined(CONFIG_ETRAX_FAST_TIMER)
		if (info->rs485.enabled) {
			/* Set a short timer to toggle RTS */
			start_one_shot_timer(&fast_timers_rs485[info->line],
			                     rs485_toggle_rts_timer_function,
			                     (unsigned long)info,
			                     info->char_time_usec*2,
			                     "RS-485");
		}
#endif /* RS485 */
		return;
	}

	/* ok we can schedule a dma send of c chars starting at info->xmit.tail */
	/* set up the descriptor correctly for output */

	descr->ctrl = d_int | d_eol | d_wait; /* Wait needed for tty_wait_until_sent() */
	descr->sw_len = c;
	descr->buf = virt_to_phys(info->xmit.buf + info->xmit.tail);
	descr->status = 0;

	*info->ofirstadr = virt_to_phys(descr); /* write to R_DMAx_FIRST */
	*info->ocmdadr = 1;       /* dma command start -> R_DMAx_CMD */
	
	/* DMA is now running (hopefully) */
} /* transmit_chars */

static void 
start_transmit(struct e100_serial *info)
{
#if 0
	if (info->line == SERIAL_DEBUG_LINE)
		printk("x\n");
#endif

	info->tr_descr.sw_len = 0;
	info->tr_descr.hw_len = 0;
	info->tr_descr.status = 0;
	info->tr_running = 1;

	transmit_chars(info);
} /* start_transmit */

#ifdef CONFIG_ETRAX_SERIAL_FAST_TIMER
static int serial_fast_timer_started = 0;
static int serial_fast_timer_expired = 0;
static void flush_timeout_function(unsigned long data);
#define START_FLUSH_FAST_TIMER(info, string) {\
  unsigned long timer_flags; \
  save_flags(timer_flags); \
  cli(); \
  if (fast_timers[info->line].function == NULL) { \
    serial_fast_timer_started++; \
    TIMERD(DEBUG_LOG(info->line, "start_timer %i ", info->line)); \
    TIMERD(DEBUG_LOG(info->line, "num started: %i\n", serial_fast_timer_started)); \
    start_one_shot_timer(&fast_timers[info->line], \
                         flush_timeout_function, \
                         (unsigned long)info, \
                         info->char_time_usec*4, \
                         string); \
  } \
  else { \
    TIMERD(DEBUG_LOG(info->line, "timer %i already running\n", info->line)); \
  } \
  restore_flags(timer_flags); \
}

#else
#define START_FLUSH_FAST_TIMER(info, string)
#endif

static struct etrax_recv_buffer *
alloc_recv_buffer(unsigned int size)
{
	struct etrax_recv_buffer *buffer;

	if (!(buffer = kmalloc(sizeof *buffer + size, GFP_ATOMIC)))
		return NULL;

	buffer->next = NULL;
	buffer->length = 0;
	buffer->error = TTY_NORMAL;

	return buffer;
}

static void
append_recv_buffer(struct e100_serial *info, struct etrax_recv_buffer *buffer)
{
	unsigned long flags;

	save_flags(flags);
	cli();

	if (!info->first_recv_buffer)
		info->first_recv_buffer = buffer;
	else
		info->last_recv_buffer->next = buffer;

	info->last_recv_buffer = buffer;

	info->recv_cnt += buffer->length;
	if (info->recv_cnt > info->max_recv_cnt)
		info->max_recv_cnt = info->recv_cnt;

	restore_flags(flags);
}

static int
add_char_and_flag(struct e100_serial *info, unsigned char data, unsigned char flag)
{
	struct etrax_recv_buffer *buffer;

	if (!(buffer = alloc_recv_buffer(4)))
		return 0;