PERFORCE change 92390 for review

[Marcel Moolenaar]

http://perforce.freebsd.org/chv.cgi?CH=92390

Change 92390 by marcel at marcel_nfs on 2006/02/25 20:47:01

	Slightly change the logic of scheduling the softih. Add a
	schedih flag to the softc that signals whether to schedule
	the softc. When scheduled, the flag is cleared. Softih
	handlers set the flag again to signal that they need to
	be rescheduled. This avoids that we're rescheduling the
	softih when not needed.
	
	Schedule the softih in the source-specific interrupt
	handlers. There's no need to schedule the softih at the
	end of the generic interrupt handler.

Affected files ...

.. //depot/projects/uart/dev/uart/uart_bus.h#39 edit
.. //depot/projects/uart/dev/uart/uart_core.c#45 edit
.. //depot/projects/uart/dev/uart/uart_kbd_sun.c#7 edit
.. //depot/projects/uart/dev/uart/uart_tty.c#25 edit

Differences ...

==== //depot/projects/uart/dev/uart/uart_bus.h#39 (text+ko) ====

@@ -99,6 +99,7 @@
 	int		sc_opened:1;	/* This UART is open for business. */
 	int		sc_polled:1;	/* This UART has no interrupts. */
 	int		sc_txbusy:1;	/* This UART is transmitting. */
+	int		sc_schedih:1;	/* The softih needs (re)scheduling. */
 
 	struct uart_devinfo *sc_sysdev;	/* System device (or NULL). */
 

==== //depot/projects/uart/dev/uart/uart_core.c#45 (text+ko) ====

@@ -71,6 +71,20 @@
 }
 
 /*
+ * Schedule a soft interrupt.
+ */
+static __inline void
+uart_sched_softih(struct uart_softc *sc, uint32_t ipend)
+{
+
+	atomic_set_32(&sc->sc_ttypend, ipend);
+	if (sc->sc_schedih) {
+		swi_sched(sc->sc_softih, 0);
+		sc->sc_schedih = 0;
+	}
+}
+
+/*
  * A break condition has been detected. We treat the break condition as
  * a special case that should not happen during normal operation. When
  * the break condition is to be passed to higher levels in the form of
@@ -91,7 +105,7 @@
 	}
 #endif
 	if (sc->sc_opened)
-		atomic_set_32(&sc->sc_ttypend, SER_INT_BREAK);
+		uart_sched_softih(sc, SER_INT_BREAK);
 }
 
 /*
@@ -118,7 +132,7 @@
 		UART_RECEIVE(sc);
 		if (uart_rx_put(sc, UART_STAT_OVERRUN))
 			sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
-		atomic_set_32(&sc->sc_ttypend, SER_INT_RXREADY);
+		uart_sched_softih(sc, SER_INT_RXREADY);
 	}
 	UART_FLUSH(sc, UART_FLUSH_RECEIVER);
 }
@@ -145,7 +159,7 @@
 	}
 #endif
 	if (sc->sc_opened)
-		atomic_set_32(&sc->sc_ttypend, SER_INT_RXREADY);
+		uart_sched_softih(sc, SER_INT_RXREADY);
 	else
 		sc->sc_rxput = sc->sc_rxget;	/* Ignore received data. */
 }
@@ -184,8 +198,10 @@
 		old = sc->sc_ttypend;
 		new = old & ~SER_MASK_STATE;
 		new |= sig & SER_INT_SIGMASK;
-		new |= SER_INT_SIGCHG;
 	} while (!atomic_cmpset_32(&sc->sc_ttypend, old, new));
+
+	if (sc->sc_opened)
+		uart_sched_softih(sc, SER_INT_SIGCHG);
 }
 
 /*
@@ -198,7 +214,7 @@
 
 	if (sc->sc_txbusy) {
 		sc->sc_txbusy = 0;
-		atomic_set_32(&sc->sc_ttypend, SER_INT_TXIDLE);
+		uart_sched_softih(sc, SER_INT_TXIDLE);
 	}
 }
 
@@ -220,9 +236,6 @@
 		if (ipend & SER_INT_TXIDLE)
 			uart_intr_txidle(sc);
 	}
-
-	if (sc->sc_opened && sc->sc_ttypend != 0)
-		swi_sched(sc->sc_softih, 0);
 }
 
 driver_intr_t *

==== //depot/projects/uart/dev/uart/uart_kbd_sun.c#7 (text+ko) ====

@@ -258,6 +258,7 @@
 		    &sunkbd_softc, SWI_TTY, INTR_TYPE_TTY, &sc->sc_softih);
 
 		sc->sc_opened = 1;
+		sc->sc_schedih = 1;
 		KBD_INIT_DONE(&sunkbd_softc.sc_kbd);
 	}
 
@@ -273,6 +274,7 @@
 	if (sc->sc_uart->sc_leaving)
 		return;
 
+	sc->sc_uart->sc_schedih = 1;
 	pend = atomic_readandclear_32(&sc->sc_uart->sc_ttypend);
 	if (!(pend & SER_INT_MASK))
 		return;

==== //depot/projects/uart/dev/uart/uart_tty.c#25 (text+ko) ====

@@ -306,6 +306,7 @@
 	if (sc->sc_leaving)
 		return;
 
+	sc->sc_schedih = 1;
 	pend = atomic_readandclear_32(&sc->sc_ttypend);
 	if (!(pend & SER_INT_MASK))
 		return;
@@ -379,6 +380,7 @@
 
 	swi_add(&tty_intr_event, uart_driver_name, uart_tty_intr, sc, SWI_TTY,
 	    INTR_TYPE_TTY, &sc->sc_softih);
+	sc->sc_schedih = 1;
 
 	ttycreate(tp, TS_CALLOUT, "u%r", unit);