sab82532.c

讲述linux的初始化过程

	unsigned long flags;
	char stat_buf[30];
	int ret;

	ret = sprintf(buf, "%u: uart:SAB82532 ", info->line);
	switch (info->type) {
		case 0:
			ret += sprintf(buf+ret, "V1.0 ");
			break;
		case 1:
			ret += sprintf(buf+ret, "V2.0 ");
			break;
		case 2:
			ret += sprintf(buf+ret, "V3.2 ");
			break;
		default:
			ret += sprintf(buf+ret, "V?.? ");
			break;
	}
	ret += sprintf(buf+ret, "port:%lX irq:%s",
		       (unsigned long)info->regs, __irq_itoa(info->irq));

	if (!info->regs) {
		ret += sprintf(buf+ret, "\n");
		return ret;
	}

	/*
	 * Figure out the current RS-232 lines
	 */
	stat_buf[0] = 0;
	stat_buf[1] = 0;
	save_flags(flags); cli();
	if (readb(&info->regs->r.mode) & SAB82532_MODE_RTS) {
		if (!(readb(&info->regs->r.mode) & SAB82532_MODE_FRTS))
			strcat(stat_buf, "|RTS");
	} else {
		strcat(stat_buf, "|RTS");
	}
	if (readb(&info->regs->r.star) & SAB82532_STAR_CTS)
		strcat(stat_buf, "|CTS");
	if (!(readb(&info->regs->r.pvr) & info->pvr_dtr_bit))
		strcat(stat_buf, "|DTR");
	if (!(readb(&info->regs->r.pvr) & info->pvr_dsr_bit))
		strcat(stat_buf, "|DSR");
	if (!(readb(&info->regs->r.vstr) & SAB82532_VSTR_CD))
		strcat(stat_buf, "|CD");
	restore_flags(flags);

	if (info->baud)
		ret += sprintf(buf+ret, " baud:%u", info->baud);

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

	if (info->icount.frame)
		ret += sprintf(buf+ret, " fe:%u", info->icount.frame);

	if (info->icount.parity)
		ret += sprintf(buf+ret, " pe:%u", info->icount.parity);

	if (info->icount.brk)
		ret += sprintf(buf+ret, " brk:%u", info->icount.brk);

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

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

int sab82532_read_proc(char *page, char **start, off_t off, int count,
		       int *eof, void *data)
{
	struct sab82532 *info = sab82532_chain;
	off_t begin = 0;
	int len = 0;

	len += sprintf(page, "serinfo:1.0 driver:%s\n", serial_version);
	for (info = sab82532_chain; info && len < 4000; info = info->next) {
		len += line_info(page + len, info);
		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 + (off-begin);
	return ((count < begin+len-off) ? count : begin+len-off);
}

/*
 * ---------------------------------------------------------------------
 * sab82532_init() and friends
 *
 * sab82532_init() is called at boot-time to initialize the serial driver.
 * ---------------------------------------------------------------------
 */
static int __init get_sab82532(unsigned long *memory_start)
{
	struct linux_ebus *ebus;
	struct linux_ebus_device *edev = 0;
	struct sab82532 *sab;
	unsigned long regs, offset;
	int i;

	for_each_ebus(ebus) {
		for_each_ebusdev(edev, ebus) {
			if (!strcmp(edev->prom_name, "se"))
				goto ebus_done;
		}
	}
ebus_done:
	if (!edev)
		return -ENODEV;

	regs = edev->resource[0].start;
	offset = sizeof(union sab82532_async_regs);

	for (i = 0; i < 2; i++) {
		if (memory_start) {
			*memory_start = (*memory_start + 7) & ~(7);
			sab = (struct sab82532 *)*memory_start;
			*memory_start += sizeof(struct sab82532);
		} else {
			sab = (struct sab82532 *)kmalloc(sizeof(struct sab82532),
							 GFP_KERNEL);
			if (!sab) {
				printk("sab82532: can't alloc sab struct\n");
				break;
			}
		}
		memset(sab, 0, sizeof(struct sab82532));

		sab->regs = ioremap(regs + offset, sizeof(union sab82532_async_regs));
		sab->irq = edev->irqs[0];
		sab->line = 1 - i;
		sab->xmit_fifo_size = 32;
		sab->recv_fifo_size = 32;

		writeb(SAB82532_IPC_IC_ACT_LOW, &sab->regs->w.ipc);

		sab->next = sab82532_chain;
		sab82532_chain = sab;

		offset -= sizeof(union sab82532_async_regs);
	}
	return 0;
}

#ifndef MODULE
static void __init sab82532_kgdb_hook(int line)
{
	prom_printf("sab82532: kgdb support is not implemented, yet\n");
	prom_halt();
}
#endif

static inline void __init show_serial_version(void)
{
	char *revision = "$Revision: 1.54 $";
	char *version, *p;

	version = strchr(revision, ' ');
	strcpy(serial_version, ++version);
	p = strchr(serial_version, ' ');
	*p = '\0';
	printk("SAB82532 serial driver version %s\n", serial_version);
}

extern int su_num_ports;

/*
 * The serial driver boot-time initialization code!
 */
int __init sab82532_init(void)
{
	struct sab82532 *info;
	int i;

	if (!sab82532_chain)
		get_sab82532(0);
	if (!sab82532_chain)
		return -ENODEV;

	init_bh(SERIAL_BH, do_serial_bh);

	show_serial_version();

	/* Initialize the tty_driver structure */
	memset(&serial_driver, 0, sizeof(struct tty_driver));
	serial_driver.magic = TTY_DRIVER_MAGIC;
	serial_driver.driver_name = "serial";
#ifdef CONFIG_DEVFS_FS
	serial_driver.name = "tts/%d";
#else
	serial_driver.name = "ttyS";
#endif
	serial_driver.major = TTY_MAJOR;
	serial_driver.minor_start = 64 + su_num_ports;
	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 =
		B9600 | CS8 | CREAD | HUPCL | CLOCAL;
	serial_driver.flags = TTY_DRIVER_REAL_RAW;
	serial_driver.refcount = &sab82532_refcount;
	serial_driver.table = sab82532_table;
	serial_driver.termios = sab82532_termios;
	serial_driver.termios_locked = sab82532_termios_locked;

	serial_driver.open = sab82532_open;
	serial_driver.close = sab82532_close;
	serial_driver.write = sab82532_write;
	serial_driver.put_char = sab82532_put_char;
	serial_driver.flush_chars = sab82532_flush_chars;
	serial_driver.write_room = sab82532_write_room;
	serial_driver.chars_in_buffer = sab82532_chars_in_buffer;
	serial_driver.flush_buffer = sab82532_flush_buffer;
	serial_driver.ioctl = sab82532_ioctl;
	serial_driver.throttle = sab82532_throttle;
	serial_driver.unthrottle = sab82532_unthrottle;
	serial_driver.send_xchar = sab82532_send_xchar;
	serial_driver.set_termios = sab82532_set_termios;
	serial_driver.stop = sab82532_stop;
	serial_driver.start = sab82532_start;
	serial_driver.hangup = sab82532_hangup;
	serial_driver.break_ctl = sab82532_break;
	serial_driver.wait_until_sent = sab82532_wait_until_sent;
	serial_driver.read_proc = sab82532_read_proc;

	/*
	 * The callout device is just like normal device except for
	 * major number and the subtype code.
	 */
	callout_driver = serial_driver;
#ifdef CONFIG_DEVFS_FS
	callout_driver.name = "cua/%d";
#else
	callout_driver.name = "cua";
#endif
	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");

	for (info = sab82532_chain, i = 0; info; info = info->next, i++) {
		info->magic = SERIAL_MAGIC;

		info->type = readb(&info->regs->r.vstr) & 0x0f;
		writeb(~((1 << 1) | (1 << 2) | (1 << 4)), &info->regs->w.pcr);
		writeb(0xff, &info->regs->w.pim);
		if (info->line == 0) {
			info->pvr_dsr_bit = (1 << 0);
			info->pvr_dtr_bit = (1 << 1);
		} else {
			info->pvr_dsr_bit = (1 << 3);
			info->pvr_dtr_bit = (1 << 2);
		}
		writeb((1 << 1) | (1 << 2) | (1 << 4), &info->regs->w.pvr);
		writeb(readb(&info->regs->rw.mode) | SAB82532_MODE_FRTS, &info->regs->rw.mode);
		writeb(readb(&info->regs->rw.mode) | SAB82532_MODE_RTS, &info->regs->rw.mode);

		info->custom_divisor = 16;
		info->close_delay = 5*HZ/10;
		info->closing_wait = 30*HZ;
		info->tec_timeout = SAB82532_MAX_TEC_TIMEOUT;
		info->cec_timeout = SAB82532_MAX_CEC_TIMEOUT;
		info->x_char = 0;
		info->event = 0;	
		info->blocked_open = 0;
		info->tqueue.routine = do_softint;
		info->tqueue.data = info;
		info->tqueue_hangup.routine = do_serial_hangup;
		info->tqueue_hangup.data = info;
		info->callout_termios = callout_driver.init_termios;
		info->normal_termios = serial_driver.init_termios;
		init_waitqueue_head(&info->open_wait);
		init_waitqueue_head(&info->close_wait);
		init_waitqueue_head(&info->delta_msr_wait);
		info->icount.cts = info->icount.dsr = 
			info->icount.rng = info->icount.dcd = 0;
		info->icount.rx = info->icount.tx = 0;
		info->icount.frame = info->icount.parity = 0;
		info->icount.overrun = info->icount.brk = 0;

		if (!(info->line & 0x01)) {
			if (request_irq(info->irq, sab82532_interrupt, SA_SHIRQ,
					"serial(sab82532)", info)) {
				printk("sab82532: can't get IRQ %x\n",
				       info->irq);
				panic("sab82532 initialization failed");
			}
		}
	
		printk(KERN_INFO
		       "ttyS%02d at 0x%lx (irq = %s) is a SAB82532 %s\n",
		       info->line + su_num_ports, (unsigned long)info->regs,
		       __irq_itoa(info->irq), sab82532_version[info->type]);
	}

#ifdef SERIAL_LOG_DEVICE
	dprint_init(SERIAL_LOG_DEVICE);
#endif
	return 0;
}

int __init sab82532_probe(void)
{
	int node, enode, snode;
	char model[32];
	int len;

        node = prom_getchild(prom_root_node);
	node = prom_searchsiblings(node, "pci");

	/*
	 * Check for SUNW,sabre on Ultra 5/10/AXi.
	 */
	len = prom_getproperty(node, "model", model, sizeof(model));
	if ((len > 0) && !strncmp(model, "SUNW,sabre", len)) {
        	node = prom_getchild(node);
		node = prom_searchsiblings(node, "pci");
	}

	/*
	 * For each PCI bus...
	 */
	while (node) {
		enode = prom_getchild(node);
		enode = prom_searchsiblings(enode, "ebus");

		/*
		 * For each EBus on this PCI...
		 */
		while (enode) {
			snode = prom_getchild(enode);
			snode = prom_searchsiblings(snode, "se");
			if (snode)
				goto found;

			enode = prom_getsibling(enode);
			enode = prom_searchsiblings(enode, "ebus");
		}
		node = prom_getsibling(node);
		node = prom_searchsiblings(node, "pci");
	}
	return -ENODEV;

found:
#ifdef CONFIG_SERIAL_CONSOLE
	sunserial_setinitfunc(sab82532_console_init);
#endif
#ifndef MODULE
	sunserial_setinitfunc(sab82532_init);
	rs_ops.rs_kgdb_hook = sab82532_kgdb_hook;
#endif
	return 0;
}

#ifdef MODULE
int init_module(void)
{
	if (get_sab82532(0))
		return -ENODEV;

	return sab82532_init();
}

void cleanup_module(void) 
{
	struct sab82532 *sab;
	unsigned long flags;
	int e1, e2;

	/* printk("Unloading %s: version %s\n", serial_name, serial_version); */
	save_flags(flags);
	cli();
        remove_bh(SERIAL_BH);
	if ((e1 = tty_unregister_driver(&serial_driver)))
		printk("SERIAL: failed to unregister serial driver (%d)\n",
		       e1);
	if ((e2 = tty_unregister_driver(&callout_driver)))
		printk("SERIAL: failed to unregister callout driver (%d)\n", 
		       e2);
	restore_flags(flags);

	if (tmp_buf) {
		free_page((unsigned long) tmp_buf);
		tmp_buf = NULL;
	}
	for (sab = sab82532_chain; sab; sab = sab->next) {
		if (!(sab->line & 0x01))
			free_irq(sab->irq, sab);
		iounmap(sab->regs);
	}
}
#endif /* MODULE */

#ifdef CONFIG_SERIAL_CONSOLE
static void
batten_down_hatches(struct sab82532 *info)
{
	unsigned char saved_rfc, tmp;

	if (!stop_a_enabled)
		return;

	/* If we are doing kadb, we call the debugger
	 * else we just drop into the boot monitor.
	 * Note that we must flush the user windows
	 * first before giving up control.
	 */
	printk("\n");
	flush_user_windows();

	/*
	 * Set FIFO to single character mode.
	 */
	saved_rfc = readb(&info->regs->r.rfc);
	tmp = readb(&info->regs->rw.rfc);
	tmp &= ~(SAB82532_RFC_RFDF);
	writeb(tmp, &info->regs->rw.rfc);
	sab82532_cec_wait(info);
	writeb(SAB82532_CMDR_RRES, &info->regs->w.cmdr);

#ifndef __sparc_v9__
	if ((((unsigned long)linux_dbvec) >= DEBUG_FIRSTVADDR) &&
	    (((unsigned long)linux_dbvec) <= DEBUG_LASTVADDR))
		sp_enter_debugger();
	else
#endif
		prom_cmdline();

	/*
	 * Reset FIFO to character + status mode.
	 */
	writeb(saved_rfc, &info->regs->w.rfc);
	sab82532_cec_wait(info);
	writeb(SAB82532_CMDR_RRES, &info->regs->w.cmdr);
}

static __inline__ void
sab82532_console_putchar(struct sab82532 *info, char c)
{
	unsigned long flags;

	save_flags(flags); cli();
	sab82532_tec_wait(info);
	writeb(c, &info->regs->w.tic);
	restore_flags(flags);
}

static void
sab82532_console_write(struct console *con, const char *s, unsigned n)
{
	struct sab82532 *info;
	int i;

	info = sab82532_chain;
	for (i = con->index; i; i--) {
		info = info->next;
		if (!info)
			return;
	}

	for (i = 0; i < n; i++) {
		if (*s == '\n')
			sab82532_console_putchar(info, '\r');
		sab82532_console_putchar(info, *s++);
	}
	sab82532_tec_wait(info);
}

static int
sab82532_console_wait_key(struct console *con)