[MIPS] zs.c: Resurrect the deceased zs.c for now.

Not that it's meant to be sustained for long, but from time to time it's
useful to have some console...

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 70 insertions, 93 deletions

diff --git a/drivers/tc/zs.c b/drivers/tc/zs.c
index c52af73a251b..6756d0fab6fe 100644
--- a/drivers/tc/zs.c
+++ b/drivers/tc/zs.c
@@ -6,7 +6,7 @@
  *
  * DECstation changes
  * Copyright (C) 1998-2000 Harald Koerfgen
- * Copyright (C) 2000, 2001, 2002, 2003, 2004  Maciej W. Rozycki
+ * Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005  Maciej W. Rozycki
  *
  * For the rest of the code the original Copyright applies:
  * Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)
@@ -55,6 +55,7 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/ioport.h>
+#include <linux/spinlock.h>
 #ifdef CONFIG_SERIAL_DEC_CONSOLE
 #include <linux/console.h>
 #endif
@@ -63,7 +64,6 @@
 #include <asm/pgtable.h>
 #include <asm/irq.h>
 #include <asm/system.h>
-#include <asm/uaccess.h>
 #include <asm/bootinfo.h>
 
 #include <asm/dec/interrupts.h>
@@ -128,6 +128,8 @@ static struct zs_parms ds_parms = {
 
 #define BUS_PRESENT (DS_BUS_PRESENT)
 
+DEFINE_SPINLOCK(zs_lock);
+
 struct dec_zschannel zs_channels[NUM_CHANNELS];
 struct dec_serial zs_soft[NUM_CHANNELS];
 int zs_channels_found;
@@ -159,8 +161,6 @@ static unsigned char zs_init_regs[16] __initdata = {
 	0				/* write 15 */
 };
 
-DECLARE_TASK_QUEUE(tq_zs_serial);
-
 static struct tty_driver *serial_driver;
 
 /* serial subtype definitions */
@@ -294,8 +294,7 @@ static inline void zs_rtsdtr(struct dec_serial *info, int which, int set)
 {
         unsigned long flags;
 
-
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 	if (info->zs_channel != info->zs_chan_a) {
 		if (set) {
 			info->zs_chan_a->curregs[5] |= (which & (RTS | DTR));
@@ -304,7 +303,7 @@ static inline void zs_rtsdtr(struct dec_serial *info, int which, int set)
 		}
 		write_zsreg(info->zs_chan_a, 5, info->zs_chan_a->curregs[5]);
 	}
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 /* Utility routines for the Zilog */
@@ -345,12 +344,10 @@ static inline void rs_recv_clear(struct dec_zschannel *zsc)
  * 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 dec_serial *info,
-				  int event)
+static _INLINE_ void rs_sched_event(struct dec_serial *info, int event)
 {
 	info->event |= 1 << event;
-	queue_task(&info->tqueue, &tq_zs_serial);
-	mark_bh(SERIAL_BH);
+	tasklet_schedule(&info->tlet);
 }
 
 static _INLINE_ void receive_chars(struct dec_serial *info,
@@ -497,9 +494,10 @@ static _INLINE_ void status_handle(struct dec_serial *info)
 /*
  * This is the serial driver's generic interrupt routine
  */
-void rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+static irqreturn_t rs_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
 	struct dec_serial *info = (struct dec_serial *) dev_id;
+	irqreturn_t status = IRQ_NONE;
 	unsigned char zs_intreg;
 	int shift;
 
@@ -521,6 +519,8 @@ void rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 		if ((zs_intreg & CHAN_IRQMASK) == 0)
 			break;
 
+		status = IRQ_HANDLED;
+
 		if (zs_intreg & CHBRxIP) {
 			receive_chars(info, regs);
 		}
@@ -534,6 +534,8 @@ void rs_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 
 	/* Why do we need this ? */
 	write_zsreg(info->zs_channel, 0, RES_H_IUS);
+
+	return status;
 }
 
 #ifdef ZS_DEBUG_REGS
@@ -578,12 +580,12 @@ static void rs_stop(struct tty_struct *tty)
 		return;
 
 #if 1
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 	if (info->zs_channel->curregs[5] & TxENAB) {
 		info->zs_channel->curregs[5] &= ~TxENAB;
 		write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
 	}
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 #endif
 }
 
@@ -595,7 +597,7 @@ static void rs_start(struct tty_struct *tty)
 	if (serial_paranoia_check(info, tty->name, "rs_start"))
 		return;
 
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 #if 1
 	if (info->xmit_cnt && info->xmit_buf && !(info->zs_channel->curregs[5] & TxENAB)) {
 		info->zs_channel->curregs[5] |= TxENAB;
@@ -606,7 +608,7 @@ static void rs_start(struct tty_struct *tty)
 		transmit_chars(info);
 	}
 #endif
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 /*
@@ -618,12 +620,8 @@ static void rs_start(struct tty_struct *tty)
  * interrupt driver proper are done; the interrupt driver schedules
  * them using rs_sched_event(), and they get done here.
  */
-static void do_serial_bh(void)
-{
-	run_task_queue(&tq_zs_serial);
-}
 
-static void do_softint(void *private_)
+static void do_softint(unsigned long private_)
 {
 	struct dec_serial	*info = (struct dec_serial *) private_;
 	struct tty_struct	*tty;
@@ -634,10 +632,11 @@ static void do_softint(void *private_)
 
 	if (test_and_clear_bit(RS_EVENT_WRITE_WAKEUP, &info->event)) {
 		tty_wakeup(tty);
+		wake_up_interruptible(&tty->write_wait);
 	}
 }
 
-int zs_startup(struct dec_serial * info)
+static int zs_startup(struct dec_serial * info)
 {
 	unsigned long flags;
 
@@ -650,7 +649,7 @@ int zs_startup(struct dec_serial * info)
 			return -ENOMEM;
 	}
 
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 
 #ifdef SERIAL_DEBUG_OPEN
 	printk("starting up ttyS%d (irq %d)...", info->line, info->irq);
@@ -706,7 +705,7 @@ int zs_startup(struct dec_serial * info)
 	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
 
 	info->flags |= ZILOG_INITIALIZED;
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 	return 0;
 }
 
@@ -726,7 +725,7 @@ static void shutdown(struct dec_serial * info)
 	       info->irq);
 #endif
 
-	save_flags(flags); cli(); /* Disable interrupts */
+	spin_lock_irqsave(&zs_lock, flags);
 
 	if (info->xmit_buf) {
 		free_page((unsigned long) info->xmit_buf);
@@ -749,7 +748,7 @@ static void shutdown(struct dec_serial * info)
 		set_bit(TTY_IO_ERROR, &info->tty->flags);
 
 	info->flags &= ~ZILOG_INITIALIZED;
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 /*
@@ -785,7 +784,7 @@ static void change_speed(struct dec_serial *info)
 			i += 15;
 	}
 
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 	info->zs_baud = baud_table[i];
 	if (info->zs_baud) {
 		brg = BPS_TO_BRG(info->zs_baud, zs_parms->clock/info->clk_divisor);
@@ -858,7 +857,7 @@ static void change_speed(struct dec_serial *info)
 	/* Load up the new values */
 	load_zsregs(info->zs_channel, info->zs_channel->curregs);
 
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 static void rs_flush_chars(struct tty_struct *tty)
@@ -874,9 +873,9 @@ static void rs_flush_chars(struct tty_struct *tty)
 		return;
 
 	/* Enable transmitter */
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 	transmit_chars(info);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 static int rs_write(struct tty_struct * tty,
@@ -892,26 +891,17 @@ static int rs_write(struct tty_struct * tty,
 	if (!tty || !info->xmit_buf)
 		return 0;
 
-	save_flags(flags);
 	while (1) {
-		cli();
+		spin_lock_irqsave(&zs_lock, flags);
 		c = min(count, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
 				   SERIAL_XMIT_SIZE - info->xmit_head));
 		if (c <= 0)
 			break;
 
-		if (from_user) {
-			down(&tmp_buf_sem);
-			copy_from_user(tmp_buf, buf, c);
-			c = min(c, min(SERIAL_XMIT_SIZE - info->xmit_cnt - 1,
-				       SERIAL_XMIT_SIZE - info->xmit_head));
-			memcpy(info->xmit_buf + info->xmit_head, tmp_buf, c);
-			up(&tmp_buf_sem);
-		} else
-			memcpy(info->xmit_buf + info->xmit_head, buf, c);
+		memcpy(info->xmit_buf + info->xmit_head, buf, c);
 		info->xmit_head = (info->xmit_head + c) & (SERIAL_XMIT_SIZE-1);
 		info->xmit_cnt += c;
-		restore_flags(flags);
+		spin_unlock_irqrestore(&zs_lock, flags);
 		buf += c;
 		count -= c;
 		total += c;
@@ -920,7 +910,7 @@ static int rs_write(struct tty_struct * tty,
 	if (info->xmit_cnt && !tty->stopped && !info->tx_stopped
 	    && !info->tx_active)
 		transmit_chars(info);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 	return total;
 }
 
@@ -952,9 +942,9 @@ static void rs_flush_buffer(struct tty_struct *tty)
 
 	if (serial_paranoia_check(info, tty->name, "rs_flush_buffer"))
 		return;
-	cli();
+	spin_lock_irq(&zs_lock);
 	info->xmit_cnt = info->xmit_head = info->xmit_tail = 0;
-	sti();
+	spin_unlock_irq(&zs_lock);
 	tty_wakeup(tty);
 }
 
@@ -982,11 +972,11 @@ static void rs_throttle(struct tty_struct * tty)
 		return;
 
 	if (I_IXOFF(tty)) {
-		save_flags(flags); cli();
+		spin_lock_irqsave(&zs_lock, flags);
 		info->x_char = STOP_CHAR(tty);
 		if (!info->tx_active)
 			transmit_chars(info);
-		restore_flags(flags);
+		spin_unlock_irqrestore(&zs_lock, flags);
 	}
 
 	if (C_CRTSCTS(tty)) {
@@ -1010,7 +1000,7 @@ static void rs_unthrottle(struct tty_struct * tty)
 		return;
 
 	if (I_IXOFF(tty)) {
-		save_flags(flags); cli();
+		spin_lock_irqsave(&zs_lock, flags);
 		if (info->x_char)
 			info->x_char = 0;
 		else {
@@ -1018,7 +1008,7 @@ static void rs_unthrottle(struct tty_struct * tty)
 			if (!info->tx_active)
 				transmit_chars(info);
 		}
-		restore_flags(flags);
+		spin_unlock_irqrestore(&zs_lock, flags);
 	}
 
 	if (C_CRTSCTS(tty)) {
@@ -1111,9 +1101,9 @@ static int get_lsr_info(struct dec_serial * info, unsigned int *value)
 {
 	unsigned char status;
 
-	cli();
+	spin_lock(&zs_lock);
 	status = read_zsreg(info->zs_channel, 0);
-	sti();
+	spin_unlock_irq(&zs_lock);
 	put_user(status,value);
 	return 0;
 }
@@ -1136,11 +1126,11 @@ static int rs_tiocmget(struct tty_struct *tty, struct file *file)
 	if (info->zs_channel == info->zs_chan_a)
 		result = 0;
 	else {
-		cli();
+		spin_lock(&zs_lock);
 		control = info->zs_chan_a->curregs[5];
 		status_a = read_zsreg(info->zs_chan_a, 0);
 		status_b = read_zsreg(info->zs_channel, 0);
-		sti();
+		spin_unlock_irq(&zs_lock);
 		result =  ((control  & RTS) ? TIOCM_RTS: 0)
 			| ((control  & DTR) ? TIOCM_DTR: 0)
 			| ((status_b & DCD) ? TIOCM_CAR: 0)
@@ -1155,8 +1145,6 @@ static int rs_tiocmset(struct tty_struct *tty, struct file *file,
                        unsigned int set, unsigned int clear)
 {
 	struct dec_serial * info = (struct dec_serial *)tty->driver_data;
-	int error;
-	unsigned int arg, bits;
 
 	if (info->hook)
 		return -ENODEV;
@@ -1170,8 +1158,7 @@ static int rs_tiocmset(struct tty_struct *tty, struct file *file,
 	if (info->zs_channel == info->zs_chan_a)
 		return 0;
 
-	get_user(arg, value);
-	cli();
+	spin_lock(&zs_lock);
 	if (set & TIOCM_RTS)
 		info->zs_chan_a->curregs[5] |= RTS;
 	if (set & TIOCM_DTR)
@@ -1181,7 +1168,7 @@ static int rs_tiocmset(struct tty_struct *tty, struct file *file,
 	if (clear & TIOCM_DTR)
 		info->zs_chan_a->curregs[5] &= ~DTR;
 	write_zsreg(info->zs_chan_a, 5, info->zs_chan_a->curregs[5]);
-	sti();
+	spin_unlock_irq(&zs_lock);
 	return 0;
 }
 
@@ -1198,19 +1185,18 @@ static void rs_break(struct tty_struct *tty, int break_state)
 	if (!info->port)
 		return;
 
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 	if (break_state == -1)
 		info->zs_channel->curregs[5] |= SND_BRK;
 	else
 		info->zs_channel->curregs[5] &= ~SND_BRK;
 	write_zsreg(info->zs_channel, 5, info->zs_channel->curregs[5]);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 static int rs_ioctl(struct tty_struct *tty, struct file * file,
 		    unsigned int cmd, unsigned long arg)
 {
-	int error;
 	struct dec_serial * info = (struct dec_serial *)tty->driver_data;
 
 	if (info->hook)
@@ -1287,10 +1273,10 @@ static void rs_close(struct tty_struct *tty, struct file * filp)
 	if (!info || serial_paranoia_check(info, tty->name, "rs_close"))
 		return;
 
-	save_flags(flags); cli();
+	spin_lock_irqsave(&zs_lock, flags);
 
 	if (tty_hung_up_p(filp)) {
-		restore_flags(flags);
+		spin_unlock_irqrestore(&zs_lock, flags);
 		return;
 	}
 
@@ -1315,7 +1301,7 @@ static void rs_close(struct tty_struct *tty, struct file * filp)
 		info->count = 0;
 	}
 	if (info->count) {
-		restore_flags(flags);
+		spin_unlock_irqrestore(&zs_lock, flags);
 		return;
 	}
 	info->flags |= ZILOG_CLOSING;
@@ -1358,7 +1344,7 @@ static void rs_close(struct tty_struct *tty, struct file * filp)
 	}
 	info->flags &= ~(ZILOG_NORMAL_ACTIVE|ZILOG_CLOSING);
 	wake_up_interruptible(&info->close_wait);
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 /*
@@ -1398,7 +1384,7 @@ static void rs_wait_until_sent(struct tty_struct *tty, int timeout)
 /*
  * rs_hangup() --- called by tty_hangup() when a hangup is signaled.
  */
-void rs_hangup(struct tty_struct *tty)
+static void rs_hangup(struct tty_struct *tty)
 {
 	struct dec_serial * info = (struct dec_serial *)tty->driver_data;
 
@@ -1466,16 +1452,16 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
 	printk("block_til_ready before block: ttyS%d, count = %d\n",
 	       info->line, info->count);
 #endif
-	cli();
+	spin_lock(&zs_lock);
 	if (!tty_hung_up_p(filp))
 		info->count--;
-	sti();
+	spin_unlock_irq(&zs_lock);
 	info->blocked_open++;
 	while (1) {
-		cli();
+		spin_lock(&zs_lock);
 		if (tty->termios->c_cflag & CBAUD)
 			zs_rtsdtr(info, RTS | DTR, 1);
-		sti();
+		spin_unlock_irq(&zs_lock);
 		set_current_state(TASK_INTERRUPTIBLE);
 		if (tty_hung_up_p(filp) ||
 		    !(info->flags & ZILOG_INITIALIZED)) {
@@ -1523,7 +1509,7 @@ static int block_til_ready(struct tty_struct *tty, struct file * filp,
  * the IRQ chain.   It also performs the serial-specific
  * initialization for the tty structure.
  */
-int rs_open(struct tty_struct *tty, struct file * filp)
+static int rs_open(struct tty_struct *tty, struct file * filp)
 {
 	struct dec_serial	*info;
 	int 			retval, line;
@@ -1706,7 +1692,7 @@ static void __init probe_sccs(void)
 		}
 	}
 
-	save_and_cli(flags);
+	spin_lock_irqsave(&zs_lock, flags);
 	for (n = 0; n < zs_channels_found; n++) {
 		if (n % 2 == 0) {
 			write_zsreg(zs_soft[n].zs_chan_a, R9, FHWRES);
@@ -1716,7 +1702,7 @@ static void __init probe_sccs(void)
 		load_zsregs(zs_soft[n].zs_channel,
 			    zs_soft[n].zs_channel->curregs);
 	}
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 }
 
 static struct tty_operations serial_ops = {
@@ -1749,9 +1735,6 @@ int __init zs_init(void)
 	if(!BUS_PRESENT)
 		return -ENODEV;
 
-	/* Setup base handler, and timer table. */
-	init_bh(SERIAL_BH, do_serial_bh);
-
 	/* Find out how many Z8530 SCCs we have */
 	if (zs_chain == 0)
 		probe_sccs();
@@ -1800,8 +1783,7 @@ int __init zs_init(void)
 		info->event = 0;
 		info->count = 0;
 		info->blocked_open = 0;
-		info->tqueue.routine = do_softint;
-		info->tqueue.data = info;
+		tasklet_init(&info->tlet, do_softint, (unsigned long)info);
 		init_waitqueue_head(&info->open_wait);
 		init_waitqueue_head(&info->close_wait);
 		printk("ttyS%02d at 0x%08x (irq = %d) is a Z85C30 SCC\n",
@@ -1833,8 +1815,7 @@ int __init zs_init(void)
 /*
  * polling I/O routines
  */
-static int
-zs_poll_tx_char(void *handle, unsigned char ch)
+static int zs_poll_tx_char(void *handle, unsigned char ch)
 {
 	struct dec_serial *info = handle;
 	struct dec_zschannel *chan = info->zs_channel;
@@ -1857,8 +1838,7 @@ zs_poll_tx_char(void *handle, unsigned char ch)
 		return -ENODEV;
 }
 
-static int
-zs_poll_rx_char(void *handle)
+static int zs_poll_rx_char(void *handle)
 {
 	struct dec_serial *info = handle;
         struct dec_zschannel *chan = info->zs_channel;
@@ -2037,7 +2017,7 @@ static int __init serial_console_setup(struct console *co, char *options)
 	}
 	co->cflag = cflag;
 
-	save_and_cli(flags);
+	spin_lock_irqsave(&zs_lock, flags);
 
 	/*
 	 * Set up the baud rate generator.
@@ -2092,7 +2072,7 @@ static int __init serial_console_setup(struct console *co, char *options)
 	zs_soft[co->index].clk_divisor = clk_divisor;
 	zs_soft[co->index].zs_baud = get_zsbaud(&zs_soft[co->index]);
 
-	restore_flags(flags);
+	spin_unlock_irqrestore(&zs_lock, flags);
 
 	return 0;
 }
@@ -2229,5 +2209,3 @@ void __init zs_kgdb_hook(int tty_num)
 	set_debug_traps(); /* init stub */
 }
 #endif /* ifdef CONFIG_KGDB */
-
-
diff --git a/drivers/tc/zs.h b/drivers/tc/zs.h
index c52edffa6049..13512200ceba 100644
--- a/drivers/tc/zs.h
+++ b/drivers/tc/zs.h
@@ -6,14 +6,14 @@
  *
  * Copyright (C) 1996 Paul Mackerras (Paul.Mackerras@cs.anu.edu.au)
  * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
- * Copyright (C) 2004  Maciej W. Rozycki
+ * Copyright (C) 2004, 2005  Maciej W. Rozycki
  */
 #ifndef _DECSERIAL_H
 #define _DECSERIAL_H
 
 #include <asm/dec/serial.h>
 
-#define NUM_ZSREGS    16
+#define NUM_ZSREGS 16
 
 struct serial_struct {
 	int	type;
@@ -139,8 +139,7 @@ struct dec_serial {
 	int			xmit_head;
 	int			xmit_tail;
 	int			xmit_cnt;
-	struct tq_struct	tqueue;
-	struct tq_struct	tqueue_hangup;
+	struct tasklet_struct	tlet;
 	wait_queue_head_t	open_wait;
 	wait_queue_head_t	close_wait;
 };
@@ -282,7 +281,7 @@ struct dec_serial {
 #define	DLC	4	/* Disable Lower Chain */
 #define	MIE	8	/* Master Interrupt Enable */
 #define	STATHI	0x10	/* Status high */
-#define SOFTACK 0x20    /* Software Interrupt Acknowledge */
+#define	SOFTACK	0x20	/* Software Interrupt Acknowledge */
 #define	NORESET	0	/* No reset on write to R9 */
 #define	CHRB	0x40	/* Reset channel B */
 #define	CHRA	0x80	/* Reset channel A */
@@ -395,8 +394,8 @@ struct dec_serial {
 /* Read Register 15 (value of WR 15) */
 
 /* Misc macros */
-#define ZS_CLEARERR(channel)    (write_zsreg(channel, 0, ERR_RES))
-#define ZS_CLEARFIFO(channel)   do { volatile unsigned char garbage; \
+#define ZS_CLEARERR(channel)	(write_zsreg(channel, 0, ERR_RES))
+#define ZS_CLEARFIFO(channel)	do { volatile unsigned char garbage; \
 				     garbage = read_zsdata(channel); \
 				     garbage = read_zsdata(channel); \
 				     garbage = read_zsdata(channel); \