From NetBSD; new device detaching infrastructure.

2 files changed, 186 insertions, 4 deletions

diff --git a/sys/kern/subr_autoconf.c b/sys/kern/subr_autoconf.c
index 93613bb63df..12f8234d317 100644
--- a/sys/kern/subr_autoconf.c
+++ b/sys/kern/subr_autoconf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_autoconf.c,v 1.24 1999/08/05 17:41:44 niklas Exp $	*/
+/*	$OpenBSD: subr_autoconf.c,v 1.25 1999/08/08 00:37:09 niklas Exp $	*/
 /*	$NetBSD: subr_autoconf.c,v 1.21 1996/04/04 06:06:18 cgd Exp $	*/
 
 /*
@@ -456,6 +456,7 @@ config_make_softc(parent, cf)
 	bzero(dev, ca->ca_devsize);
 	dev->dv_class = cd->cd_class;
 	dev->dv_cfdata = cf;
+	dev->dv_flags = DVF_ACTIVE;	/* always initially active */
 
 	/* If this is a STAR device, search for a free unit number */
 	if (cf->cf_fstate == FSTATE_STAR) {
@@ -511,6 +512,167 @@ config_make_softc(parent, cf)
 }
 
 /*
+ * Detach a device.  Optionally forced (e.g. because of hardware
+ * removal) and quiet.  Returns zero if successful, non-zero
+ * (an error code) otherwise.
+ *
+ * Note that this code wants to be run from a process context, so
+ * that the detach can sleep to allow processes which have a device
+ * open to run and unwind their stacks.
+ */
+int
+config_detach(dev, flags)
+	struct device *dev;
+	int flags;
+{
+	struct cfdata *cf;
+	struct cfattach *ca;
+	struct cfdriver *cd;
+#ifdef DIAGNOSTIC
+	struct device *d;
+#endif
+	int rv = 0, i;
+
+	cf = dev->dv_cfdata;
+#ifdef DIAGNOSTIC
+	if (cf->cf_fstate != FSTATE_FOUND && cf->cf_fstate != FSTATE_STAR)
+		panic("config_detach: bad device fstate");
+#endif
+	ca = cf->cf_attach;
+	cd = cf->cf_driver;
+
+	/*
+	 * Ensure the device is deactivated.  If the device doesn't
+	 * have an activation entry point, we allow DVF_ACTIVE to
+	 * remain set.  Otherwise, if DVF_ACTIVE is still set, the
+	 * device is busy, and the detach fails.
+	 */
+	if (ca->ca_activate != NULL)
+		rv = config_deactivate(dev);
+
+	/*
+	 * Try to detach the device.  If that's not possible, then
+	 * we either panic() (for the forced but failed case), or
+	 * return an error.
+	 */
+	if (rv == 0) {
+		if (ca->ca_detach != NULL)
+			rv = (*ca->ca_detach)(dev, flags);
+		else
+			rv = EOPNOTSUPP;
+	}
+	if (rv != 0) {
+		if ((flags & DETACH_FORCE) == 0)
+			return (rv);
+		else
+			panic("config_detach: forced detach of %s failed (%d)",
+			    dev->dv_xname, rv);
+	}
+
+	/*
+	 * The device has now been successfully detached.
+	 */
+
+#ifdef DIAGNOSTIC
+	/*
+	 * Sanity: If you're successfully detached, you should have no
+	 * children.  (Note that because children must be attached
+	 * after parents, we only need to search the latter part of
+	 * the list.)
+	 */
+	for (d = TAILQ_NEXT(dev, dv_list); d != NULL;
+	     d = TAILQ_NEXT(d, dv_list)) {
+		if (d->dv_parent == dev)
+			panic("config_detach: detached device has children");
+	}
+#endif
+
+	/*
+	 * Mark cfdata to show that the unit can be reused, if possible.
+	 * Note that we can only re-use a starred unit number if the unit
+	 * being detached had the last assigned unit number.
+	 */
+	for (cf = cfdata; cf->cf_driver; cf++) {
+		if (cf->cf_driver == cd) {
+			if (cf->cf_fstate == FSTATE_FOUND &&
+			    cf->cf_unit == dev->dv_unit)
+				cf->cf_fstate = FSTATE_NOTFOUND;
+			if (cf->cf_fstate == FSTATE_STAR &&
+			    cf->cf_unit == dev->dv_unit + 1)
+				cf->cf_unit--;
+		}
+	}
+
+	/*
+	 * Unlink from device list.
+	 */
+	TAILQ_REMOVE(&alldevs, dev, dv_list);
+
+	/*
+	 * Remove from cfdriver's array, tell the world, and free softc.
+	 */
+	cd->cd_devs[dev->dv_unit] = NULL;
+	if ((flags & DETACH_QUIET) == 0)
+		printf("%s detached\n", dev->dv_xname);
+	free(dev, M_DEVBUF);
+
+	/*
+	 * If the device now has no units in use, deallocate its softc array.
+	 */
+	for (i = 0; i < cd->cd_ndevs; i++)
+		if (cd->cd_devs[i] != NULL)
+			break;
+	if (i == cd->cd_ndevs) {		/* nothing found; deallocate */
+		free(cd->cd_devs, M_DEVBUF);
+		cd->cd_devs = NULL;
+		cd->cd_ndevs = 0;
+	}
+
+	/*
+	 * Return success.
+	 */
+	return (0);
+}
+
+int
+config_activate(dev)
+	struct device *dev;
+{
+	struct cfattach *ca = dev->dv_cfdata->cf_attach;
+	int rv = 0, oflags = dev->dv_flags;
+
+	if (ca->ca_activate == NULL)
+		return (EOPNOTSUPP);
+
+	if ((dev->dv_flags & DVF_ACTIVE) == 0) {
+		dev->dv_flags |= DVF_ACTIVE;
+		rv = (*ca->ca_activate)(dev, DVACT_ACTIVATE);
+		if (rv)
+			dev->dv_flags = oflags;
+	}
+	return (rv);
+}
+
+int
+config_deactivate(dev)
+	struct device *dev;
+{
+	struct cfattach *ca = dev->dv_cfdata->cf_attach;
+	int rv = 0, oflags = dev->dv_flags;
+
+	if (ca->ca_activate == NULL)
+		return (EOPNOTSUPP);
+
+	if (dev->dv_flags & DVF_ACTIVE) {
+		dev->dv_flags &= ~DVF_ACTIVE;
+		rv = (*ca->ca_activate)(dev, DVACT_DEACTIVATE);
+		if (rv)
+			dev->dv_flags = oflags;
+	}
+	return (rv);
+}
+
+/*
  * Defer the configuration of the specified device until all
  * of its parent's devices have been attached.
  */
diff --git a/sys/sys/device.h b/sys/sys/device.h
index bb241eeba60..5db3220c683 100644
--- a/sys/sys/device.h
+++ b/sys/sys/device.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: device.h,v 1.16 1999/08/05 17:41:43 niklas Exp $	*/
+/*	$OpenBSD: device.h,v 1.17 1999/08/08 00:37:09 niklas Exp $	*/
 /*	$NetBSD: device.h,v 1.15 1996/04/09 20:55:24 cgd Exp $	*/
 
 /*
@@ -63,6 +63,14 @@ enum devclass {
 	DV_TTY			/* serial line interface (???) */
 };
 
+/*
+ * Actions for ca_activate.
+ */
+enum devact {
+	DVACT_ACTIVATE,		/* activate the device */
+	DVACT_DEACTIVATE,	/* deactivate the device */
+};
+
 struct device {
 	enum	devclass dv_class;	/* this device's classification */
 	TAILQ_ENTRY(device) dv_list;	/* entry on list of all devices */
@@ -70,7 +78,12 @@ struct device {
 	int	dv_unit;		/* device unit number */
 	char	dv_xname[16];		/* external name (name + unit) */
 	struct	device *dv_parent;	/* pointer to parent device */
+	int	dv_flags;		/* misc. flags; see below */
 };
+
+/* dv_flags */
+#define	DVF_ACTIVE	0x0001		/* device is activated */
+
 TAILQ_HEAD(devicelist, device);
 
 /* `event' counters (use zero or more per device instance, as needed) */
@@ -127,10 +140,14 @@ struct cfattach {
 	size_t	  ca_devsize;		/* size of dev data (for malloc) */
 	cfmatch_t ca_match;		/* returns a match level */
 	void	(*ca_attach) __P((struct device *, struct device *, void *));
-	int	(*ca_detach) __P((struct device*));
-	int	(*ca_reprobe) __P((struct device*, struct cfdata*));
+	int	(*ca_detach) __P((struct device *, int));
+	int	(*ca_activate) __P((struct device *, enum devact));
 };
 
+/* Flags given to config_detach(), and the ca_detach function. */
+#define	DETACH_FORCE	0x01		/* force detachment; hardware gone */
+#define	DETACH_QUIET	0x02		/* don't print a notice */
+
 struct cfdriver {
 	void	**cd_devs;		/* devices found */
 	char	*cd_name;		/* device name */
@@ -179,6 +196,9 @@ struct device *config_found_sm __P((struct device *, void *, cfprint_t,
 struct device *config_rootfound __P((char *, void *));
 void config_scan __P((cfscan_t, struct device *));
 struct device *config_attach __P((struct device *, void *, void *, cfprint_t));
+int config_detach __P((struct device *, int));
+int config_activate __P((struct device *));
+int config_deactivate __P((struct device *));
 struct device *config_make_softc __P((struct device *parent,
     struct cfdata *cf));
 void config_defer __P((struct device *, void (*)(struct device *)));