Fix a race condition in kiic(4) made possible by the way the device's STOP

condition is sent. We used to put the bus in the STOP state, but returned
without waiting for that to actually occur.

Submitted by:	Marco Trillo

1 files changed, 17 insertions, 18 deletions

diff --git a/sys/powerpc/powermac/kiic.c b/sys/powerpc/powermac/kiic.c
index 0dc9f15..1f246e7 100644
--- a/sys/powerpc/powermac/kiic.c
+++ b/sys/powerpc/powermac/kiic.c
@@ -230,7 +230,7 @@ static void
 kiic_writereg(struct kiic_softc *sc, u_int reg, u_int val)
 {
 	bus_write_1(sc->sc_reg, sc->sc_regstep * reg, val);
-	DELAY(10); /* XXX why? */
+	DELAY(10); /* register access delay */
 }
 
 static u_int
@@ -289,18 +289,22 @@ kiic_intr(void *xsc)
 	}
 
 	if (isr & I2C_INT_DATA) {
-		if (sc->sc_resid > 0) {
-			if (sc->sc_flags & I2C_READING) {
+		if (sc->sc_flags & I2C_READING) {
+			if (sc->sc_resid > 0) {
 				*sc->sc_data++ = kiic_readreg(sc, DATA);
 				sc->sc_resid--;
+			}
+
+		} else {
+			if (sc->sc_resid == 0) {
+				x = kiic_readreg(sc, CONTROL);
+				x |= I2C_CT_STOP;
+				kiic_writereg(sc, CONTROL, x);
 			} else {
 				kiic_writereg(sc, DATA, *sc->sc_data++);
 				sc->sc_resid--;
 			}
 		}
-
-		if (sc->sc_resid == 0)
-			wakeup(sc->sc_dev);
 	}
 
 	if (isr & I2C_INT_STOP) {
@@ -317,7 +321,7 @@ static int
 kiic_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
 {
 	struct kiic_softc *sc;
-	int i, x, timo;
+	int i, x, timo, err;
 	uint8_t addr;
 
 	sc = device_get_softc(dev);
@@ -341,6 +345,7 @@ kiic_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
 		sc->sc_flags = I2C_BUSY;
 		addr = msgs[i].slave;
 		timo = 1000 + sc->sc_resid * 200;
+		timo += 100000;
 
 		if (msgs[i].flags & IIC_M_RD) {
 			sc->sc_flags |= I2C_READING;
@@ -353,19 +358,13 @@ kiic_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
 		x = kiic_readreg(sc, CONTROL) | I2C_CT_ADDR;
 		kiic_writereg(sc, CONTROL, x);
 
-		mtx_sleep(dev, &sc->sc_mutex, 0, "kiic", timo);
-
-		if (!(sc->sc_flags & I2C_READING)) {
-			x = kiic_readreg(sc, CONTROL) | I2C_CT_STOP;
-			kiic_writereg(sc, CONTROL, x);
-		}
-
-		mtx_sleep(dev, &sc->sc_mutex, 0, "kiic", timo);
-
+		err = mtx_sleep(dev, &sc->sc_mutex, 0, "kiic", timo);
+		
 		msgs[i].len -= sc->sc_resid;
 
-		if (sc->sc_flags & I2C_ERROR) {
-			device_printf(sc->sc_dev, "I2C_ERROR\n");
+		if ((sc->sc_flags & I2C_ERROR) || err == EWOULDBLOCK) {
+			device_printf(sc->sc_dev, "I2C error\n");
+			sc->sc_flags = 0;
 			mtx_unlock(&sc->sc_mutex);
 			return (-1);
 		}