PERFORCE change 106762 for review

[Warner Losh]

http://perforce.freebsd.org/chv.cgi?CH=106762

Change 106762 by imp at imp_lighthouse on 2006/09/27 06:24:46

	implement bus acquisision and release as kind of a poor-man's
	semaphore.  Might be a good idea to add a device owner to the
	mix for sanity checking...

Affected files ...

.. //depot/projects/arm/src/sys/arm/at91/at91_mci.c#7 edit

Differences ...

==== //depot/projects/arm/src/sys/arm/at91/at91_mci.c#7 (text+ko) ====

@@ -68,6 +68,7 @@
 	bus_dmamap_t map;
 	struct mmc_host host;
 	int wire4;
+	int bus_busy;
 };
 
 static inline uint32_t
@@ -108,7 +109,7 @@
 
 	WR4(sc, MCI_CR, MCI_CR_MCIEN);		/* Enable controller */
 	WR4(sc, MCI_IDR, 0xffffffff);		/* Turn off interrupts */
-	WR4(sc, MCI_DTOR, MCI_DTOR_DTOMUL_1M | MCI_DTOR_DTOCYC);
+	WR4(sc, MCI_DTOR, MCI_DTOR_DTOMUL_1M | 1);
 	WR4(sc, MCI_MR, 0x834a);	// XXX GROSS HACK FROM LINUX
 	WR4(sc, MCI_SDCR, 0);			/* SLOT A, 1 bit bus */
 }
@@ -133,7 +134,6 @@
 static int
 at91_mci_attach(device_t dev)
 {
-	/* XXX: asumes MCK = 60MHz */
 	struct at91_mci_softc *sc = device_get_softc(dev);
 	int err;
 	device_t child;
@@ -299,13 +299,27 @@
 static int
 at91_acquire_host(device_t brdev, device_t reqdev)
 {
-	return (EIO);	// XXX
+	struct at91_mci_softc *sc = device_get_softc(brdev);
+	int err = 0;
+
+	AT91_MCI_LOCK(sc);
+	while (sc->bus_busy)
+		msleep(sc, &sc->sc_mtx, PZERO, "mciah", hz / 5);
+	sc->bus_busy++;
+	AT91_MCI_UNLOCK(sc);
+	return (err);
 }
 
 static int
 at91_release_host(device_t brdev, device_t reqdev)
 {
-	return (EIO);	// XXX
+	struct at91_mci_softc *sc = device_get_softc(brdev);
+
+	AT91_MCI_LOCK(sc);
+	sc->bus_busy--;
+	wakeup(sc);
+	AT91_MCI_UNLOCK(sc);
+	return (0);
 }
 
 static device_method_t at91_mci_methods[] = {