[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 c52af73a25..6756d0fab6 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;