uart.c

讲述linux的初始化过程

	}
	cli();
	status = serial_in(info, UART_MSR);
	control = info ? info->MCR : serial_in(info, UART_MCR);
	sti();
	
	stat_buf[0] = 0;
	stat_buf[1] = 0;
	if (control & UART_MCR_RTS)
		strcat(stat_buf, "|RTS");
	if (status & UART_MSR_CTS)
		strcat(stat_buf, "|CTS");
	if (control & UART_MCR_DTR)
		strcat(stat_buf, "|DTR");
	if (status & UART_MSR_DSR)
		strcat(stat_buf, "|DSR");
	if (status & UART_MSR_DCD)
		strcat(stat_buf, "|CD");
	if (status & UART_MSR_RI)
		strcat(stat_buf, "|RI");

	if (info->quot) {
		ret += sprintf(buf+ret, " baud:%d",
			       state->baud_base / info->quot);
	}

	ret += sprintf(buf+ret, " tx:%d rx:%d",
		      state->icount.tx, state->icount.rx);

	if (state->icount.frame)
		ret += sprintf(buf+ret, " fe:%d", state->icount.frame);
	
	if (state->icount.parity)
		ret += sprintf(buf+ret, " pe:%d", state->icount.parity);
	
	if (state->icount.brk)
		ret += sprintf(buf+ret, " brk:%d", state->icount.brk);	

	if (state->icount.overrun)
		ret += sprintf(buf+ret, " oe:%d", state->icount.overrun);

	/*
	 * Last thing is the RS-232 status lines
	 */
	ret += sprintf(buf+ret, " %s\n", stat_buf+1);
#endif
	return ret;
}

int rs_8xx_read_proc(char *page, char **start, off_t off, int count,
		 int *eof, void *data)
{
	int i, len = 0;
	off_t	begin = 0;

	len += sprintf(page, "serinfo:1.0 driver:%s\n", serial_version);
	for (i = 0; i < NR_PORTS && len < 4000; i++) {
		len += line_info(page + len, &rs_table[i]);
		if (len+begin > off+count)
			goto done;
		if (len+begin < off) {
			begin += len;
			len = 0;
		}
	}
	*eof = 1;
done:
	if (off >= len+begin)
		return 0;
	*start = page + (begin-off);
	return ((count < begin+len-off) ? count : begin+len-off);
}

/*
 * ---------------------------------------------------------------------
 * rs_init() and friends
 *
 * rs_init() is called at boot-time to initialize the serial driver.
 * ---------------------------------------------------------------------
 */

/*
 * This routine prints out the appropriate serial driver version
 * number, and identifies which options were configured into this
 * driver.
 */
static _INLINE_ void show_serial_version(void)
{
 	printk(KERN_INFO "%s version %s\n", serial_name, serial_version);
}


/*
 * The serial console driver used during boot.  Note that these names
 * clash with those found in "serial.c", so we currently can't support
 * the 16xxx uarts and these at the same time.  I will fix this to become
 * an indirect function call from tty_io.c (or something).
 */

#ifdef CONFIG_SERIAL_CONSOLE

/*
 * Print a string to the serial port trying not to disturb any possible
 * real use of the port...
 */
static void serial_console_write(struct console *c, const char *s,
				unsigned count)
{
	struct		serial_state	*ser;
	ser_info_t			*info;
	unsigned			i;
	volatile	cbd_t		*bdp, *bdbase;
	volatile	smc_uart_t	*up;
	volatile	u_char		*cp;

	ser = rs_table + c->index;

	/* If the port has been initialized for general use, we have
	 * to use the buffer descriptors allocated there.  Otherwise,
	 * we simply use the single buffer allocated.
	 */
	if ((info = (ser_info_t *)ser->info) != NULL) {
		bdp = info->tx_cur;
		bdbase = info->tx_bd_base;
	}
	else {
		/* Pointer to UART in parameter ram.
		*/
		up = (smc_uart_t *)&immr->im_dprambase[ser->port];

		/* Get the address of the host memory buffer.
		 */
		bdp = bdbase = (cbd_t *)&immr->im_dprambase[up->smc_tbase];
	}

	/*
	 * We need to gracefully shut down the transmitter, disable
	 * interrupts, then send our bytes out.
	 */

	/*
	 * Now, do each character.  This is not as bad as it looks
	 * since this is a holding FIFO and not a transmitting FIFO.
	 * We could add the complexity of filling the entire transmit
	 * buffer, but we would just wait longer between accesses......
	 */
	for (i = 0; i < count; i++, s++) {
		/* Wait for transmitter fifo to empty.
		 * Ready indicates output is ready, and xmt is doing
		 * that, not that it is ready for us to send.
		 */
		while (bdp->cbd_sc & BD_SC_READY);
		/* Send the character out. */
		cp = __va(bdp->cbd_bufaddr);
		*cp = *s;
		
		bdp->cbd_datlen = 1;
		bdp->cbd_sc |= BD_SC_READY;

		if (bdp->cbd_sc & BD_SC_WRAP)
			bdp = bdbase;
		else
			bdp++;

		/* if a LF, also do CR... */
		if (*s == 10) {
			while (bdp->cbd_sc & BD_SC_READY);
			cp = __va(bdp->cbd_bufaddr);
			*cp = 13;
			bdp->cbd_datlen = 1;
			bdp->cbd_sc |= BD_SC_READY;

			if (bdp->cbd_sc & BD_SC_WRAP) {
				bdp = bdbase;
			}
			else {
				bdp++;
			}
		}
	}

	/*
	 * Finally, Wait for transmitter & holding register to empty
	 *  and restore the IER
	 */
	while (bdp->cbd_sc & BD_SC_READY);

	if (info)
		info->tx_cur = (cbd_t *)bdp;
}

/*
 * Receive character from the serial port.  This only works well
 * before the port is initialize for real use.
 */
static int serial_console_wait_key(struct console *co)
{
	struct serial_state		*ser;
	u_char				c, *cp;
	ser_info_t			*info;
	volatile	cbd_t		*bdp;
	volatile	smc_uart_t	*up;

	ser = rs_table + co->index;

	/* Pointer to UART in parameter ram.
	*/
	up = (smc_uart_t *)&immr->im_dprambase[ser->port];

	/* Get the address of the host memory buffer.
	 * If the port has been initialized for general use, we must
	 * use information from the port structure.
	 */
	if ((info = (ser_info_t *)ser->info))
		bdp = info->rx_cur;
	else
		bdp = (cbd_t *)&immr->im_dprambase[up->smc_rbase];

	/*
	 * We need to gracefully shut down the receiver, disable
	 * interrupts, then read the input.
	 */
	while (bdp->cbd_sc & BD_SC_EMPTY);	/* Wait for a character */
	cp = __va(bdp->cbd_bufaddr);

	if (info) {
		if (bdp->cbd_sc & BD_SC_WRAP) {
			bdp = info->rx_bd_base;
		}
		else {
			bdp++;
		}
		info->rx_cur = (cbd_t *)bdp;
	}

	c = *cp;
	return((int)c);
}

static kdev_t serial_console_device(struct console *c)
{
	return MKDEV(TTYAUX_MAJOR, 64 + c->index);
}


static struct console sercons = {
	name:		"ttyS",
	write:		serial_console_write,
	device:		serial_console_device,
	wait_key:	serial_console_wait_key,
	setup:		serial_console_setup,
	flags:		CON_PRINTBUFFER,
	index:		CONFIG_SERIAL_CONSOLE_PORT,
};

/*
 *	Register console.
 */
long __init console_8xx_init(long kmem_start, long kmem_end)
{
	register_console(&sercons);
	return kmem_start;
}

#endif

/* Default console baud rate as determined by the board information
 * structure.
 */
static	int	baud_idx;

/*
 * The serial driver boot-time initialization code!
 */
int __init rs_8xx_init(void)
{
	struct serial_state * state;
	ser_info_t	*info;
	uint		mem_addr, dp_addr;
	int		i, j, idx;
	uint		page, sblock;
	volatile	cbd_t		*bdp;
	volatile	cpm8260_t	*cp;
	volatile	smc_t		*sp;
	volatile	smc_uart_t	*up;
	volatile	scc_t		*scp;
	volatile	scc_uart_t	*sup;
	volatile	immap_t		*immap;
	volatile	iop8260_t	*io;
	
	init_bh(SERIAL_BH, do_serial_bh);

	show_serial_version();

	/* Initialize the tty_driver structure */
	
	/*memset(&serial_driver, 0, sizeof(struct tty_driver));*/
	__clear_user(&serial_driver,sizeof(struct tty_driver));
	serial_driver.magic = TTY_DRIVER_MAGIC;
	serial_driver.driver_name = "serial";
	serial_driver.name = "ttyS";
	serial_driver.major = TTY_MAJOR;
	serial_driver.minor_start = 64;
	serial_driver.num = NR_PORTS;
	serial_driver.type = TTY_DRIVER_TYPE_SERIAL;
	serial_driver.subtype = SERIAL_TYPE_NORMAL;
	serial_driver.init_termios = tty_std_termios;
	serial_driver.init_termios.c_cflag =
		baud_idx | CS8 | CREAD | HUPCL | CLOCAL;
	serial_driver.flags = TTY_DRIVER_REAL_RAW;
	serial_driver.refcount = &serial_refcount;
	serial_driver.table = serial_table;
	serial_driver.termios = serial_termios;
	serial_driver.termios_locked = serial_termios_locked;

	serial_driver.open = rs_8xx_open;
	serial_driver.close = rs_8xx_close;
	serial_driver.write = rs_8xx_write;
	serial_driver.put_char = rs_8xx_put_char;
	serial_driver.write_room = rs_8xx_write_room;
	serial_driver.chars_in_buffer = rs_8xx_chars_in_buffer;
	serial_driver.flush_buffer = rs_8xx_flush_buffer;
	serial_driver.ioctl = rs_8xx_ioctl;
	serial_driver.throttle = rs_8xx_throttle;
	serial_driver.unthrottle = rs_8xx_unthrottle;
	serial_driver.send_xchar = rs_8xx_send_xchar;
	serial_driver.set_termios = rs_8xx_set_termios;
	serial_driver.stop = rs_8xx_stop;
	serial_driver.start = rs_8xx_start;
	serial_driver.hangup = rs_8xx_hangup;
	serial_driver.wait_until_sent = rs_8xx_wait_until_sent;
	serial_driver.read_proc = rs_8xx_read_proc;
	
	/*
	 * The callout device is just like normal device except for
	 * major number and the subtype code.
	 */
	callout_driver = serial_driver;
	callout_driver.name = "cua";
	callout_driver.major = TTYAUX_MAJOR;
	callout_driver.subtype = SERIAL_TYPE_CALLOUT;
	callout_driver.read_proc = 0;
	callout_driver.proc_entry = 0;

	if (tty_register_driver(&serial_driver))
		panic("Couldn't register serial driver\n");
	if (tty_register_driver(&callout_driver))
		panic("Couldn't register callout driver\n");
	
	immap = immr;
	cp = &immap->im_cpm;
	io = &immap->im_ioport;

	/* This should have been done long ago by the early boot code,
	 * but do it again to make sure.
	 */
	*(ushort *)(&immap->im_dprambase[PROFF_SMC1_BASE]) = PROFF_SMC1;
	*(ushort *)(&immap->im_dprambase[PROFF_SMC2_BASE]) = PROFF_SMC2;

	/* Geeze, here we go....Picking I/O port bits....Lots of
	 * choices.  If you don't like mine, pick your own.
	 * Configure SMCs Tx/Rx.  SMC1 is only on Port D, SMC2 is
	 * only on Port A.  You either pick 'em, or not.
	 */
	io->iop_ppard |= 0x00c00000;
	io->iop_pdird |= 0x00400000;
	io->iop_pdird &= ~0x00800000;
	io->iop_psord &= ~0x00c00000;
#if USE_SMC2
	io->iop_ppara |= 0x00c00000;
	io->iop_pdira |= 0x00400000;
	io->iop_pdira &= ~0x00800000;
	io->iop_psora &= ~0x00c00000;
#endif

	/* Configure SCC2 and SCC3.  Be careful about the fine print.
	 * Secondary options are only available when you take away
	 * the primary option.  Unless the pins are used for something
	 * else, SCC2 and SCC3 are on Port B.
	 *	Port B,  8 - SCC3 TxD
	 *	Port B, 12 - SCC2 TxD
	 *	Port B, 14 - SCC3 RxD
	 *	Port B, 15 - SCC2 RxD
	 */
	io->iop_pparb |= 0x008b0000;
	io->iop_pdirb |= 0x00880000;
	io->iop_psorb |= 0x00880000;
	io->iop_pdirb &= ~0x00030000;
	io->iop_psorb &= ~0x00030000;

	/* Wire BRG1 to SMC1 and BRG2 to SMC2.
	*/
	immap->im_cpmux.cmx_smr = 0;

	/* Connect SCC2 and SCC3 to NMSI.  Connect BRG3 to SCC2 and
	 * BRG4 to SCC3.
	 */
	immap->im_cpmux.cmx_scr &= ~0x00ffff00;
	immap->im_cpmux.cmx_scr |= 0x00121b00;

	for (i = 0, state = rs_table; i < NR_PORTS; i++,state++) {
		state->magic = SSTATE_MAGIC;
		state->line = i;
		state->type = PORT_UNKNOWN;
		state->custom_divisor = 0;
		state->close_delay = 5*HZ/10;
		state->closing_wait = 30*HZ;
		state->callout_termios = callout_driver.init_termios;
		state->normal_termios = serial_driver.init_termios;
		state->icount.cts = state->icount.dsr = 
			state->icount.rng = state->icount.dcd = 0;
		state->icount.rx = state->icount.tx = 0;
		state->icount.frame = state->icount.parity = 0;
		state->icount.overrun = state->icount.brk = 0;
		printk(KERN_INFO "ttyS%02d at 0x%04x is a %s\n",
		       i, state->port,
		       (state->smc_scc_num < SCC_NUM_BASE) ? "SMC" : "SCC");
#ifdef CONFIG_SERIAL_CONSOLE
		/* If we just printed the message on the console port, and
		 * we are about to initialize it for general use, we have
		 * to wait a couple of character times for the CR/NL to
		 * make it out of the transmit buffer.
		 */
		if (i == CONFIG_SERIAL_CONSOLE_PORT)
			mdelay(2);
#endif
		info = kmalloc(sizeof(ser_info_t), GFP_KERNEL);
		if (info) {
			/*memset(info, 0, sizeof(ser_info_t));*/
			__clear_user(info,sizeof(ser_info_t));
			init_waitqueue_head(&info->open_wait);
			init_waitqueue_head(&info->close_wait);
			info->magic = SERIAL_MAGIC;
			info->flags = state->flags;
			info->tqueue.routine = do_softint;
			info->tqueue.data = info;
			info->tqueue_hangup.routine = do_serial_hangup;
			info->tqueue_hangup.data = info;
			info->line = i;
			info->state = state;
			state->info = (struct async_struct *)info;

			/* We need to allocate a transmit and receive buffer
			 * descriptors from dual port ram, and a character
			 * buffer area from host mem.
			 */
			dp_addr = m8260_cpm_dpalloc(sizeof(cbd_t) * RX_NUM_FIFO, 8);

			/* Allocate space for FIFOs in the host memory.
			*/
			mem_addr = m8260_cpm_hostalloc(RX_NUM_FIFO * RX_BUF_SIZE, 1);

			/* Set the physical address of the host memory
			 * buffers in the buffer descriptors, and the
			 * virtual address for us to work with.
			 */
			bdp = (cbd_t *)&immap->im_dprambase[dp_addr];
			info->rx_cur = info->rx_bd_base = (cbd_t *)bdp;

			for (j=0; j<(RX_NUM_FIFO-1); j++) {
				bdp->cbd_bufaddr = __pa(mem_addr);
				bdp->cbd_sc = BD_SC_EMPTY | BD_SC_INTRPT;
				mem_addr += RX_BUF_SIZE;
				bdp++;
			}
			bdp->cbd_bufaddr = __pa(mem_addr);
			bdp->cbd_sc = BD_SC_WRAP | BD_SC_EMPTY | BD_SC_INTRPT;

			if ((idx = state->smc_scc_num) < SCC_NUM_BASE) {
				sp = &immap->im_smc[idx];
				up = (smc_uart_t *)&immap->im_dprambase[state->port];
				up->smc_rbase = dp_addr;
			}
			else {
				scp = &immap->im_scc[idx - SCC_IDX_BASE];
				sup = (scc_uart_t *)&immap->im_dprambase[state->port];
				sup->scc_genscc.scc_rbase = dp_addr;
			}

			dp_addr = m8260_cpm_dpalloc(sizeof(cbd_t) * TX_NUM_FIFO, 8);

			/* Allocate space for FIFOs in the host memory.
			*/
			mem_addr = m8260_cpm_hostalloc(TX_NUM_FIFO * TX_BUF_SIZE, 1);

			/* Set the physical address of the host memory
			 * buffers in the buffer descriptors, and the
			 * virtual address for us to work with.
			 */
			bdp = (cbd_t *)&immap->im_dprambase[dp_addr];
			info->tx_cur = info->tx_bd_base = (cbd_t *)bdp;

			for (j=0; j<(TX_NUM_FIFO-1); j++) {
				bdp->cbd_bufaddr = __pa(mem_addr);
				bdp->cbd_sc = BD_SC_INTRPT;
				mem_addr += TX_BUF_SIZE;
				bdp++;
			}
			bdp->cbd_bufaddr = __pa(mem_addr);
			bdp->cbd_sc = (BD_SC_WRAP | BD_SC_INTRPT);

			if (idx < SCC_NUM_BASE) {
				up->smc_tbase = dp_addr;

				/* Set up the uart parameters in the
				 * param