Allow device hints to wire the unit numbers of devices.

- An "at" hint now reserves a device name.
- A new BUS_HINT_DEVICE_UNIT method is added to the bus interface.  When
  determining the unit number of a device, this method is invoked to
  let the bus driver specify the unit of a device given a specific
  devclass.  This is the only way a device can be given a name reserved
  via an "at" hint.
- Implement BUS_HINT_DEVICE_UNIT() for the acpi(4) and isa(4) bus drivers.
  Both of these busses implement this by comparing the resources for a
  given hint device with the resources enumerated by ACPI/PnPBIOS and
  wire a unit if the hint resources are a subset of the "real" resources.
- Use bus_hinted_children() for adding hinted devices on isa(4) busses
  now instead of doing it by hand.
- Remove the unit kludging from sio(4) as it is no longer necessary.

Prodding from:	peter, imp
OK'd by:	marcel
MFC after:	1 month

1 files changed, 76 insertions, 39 deletions

diff --git a/sys/isa/isahint.c b/sys/isa/isahint.c
index 01f8823..e2ce6a4 100644
--- a/sys/isa/isahint.c
+++ b/sys/isa/isahint.c
@@ -33,10 +33,11 @@ __FBSDID("$FreeBSD$");
 #include <sys/bus.h>
 #include <sys/module.h>
 #include <isa/isavar.h>
+#include <isa/isa_common.h>
 #include <machine/resource.h>
 
-static void
-isahint_add_device(device_t parent, const char *name, int unit)
+void
+isa_hinted_child(device_t parent, const char *name, int unit)
 {
 	device_t	child;
 	int		sensitive, start, count;
@@ -82,43 +83,79 @@ isahint_add_device(device_t parent, const char *name, int unit)
 	isa_set_configattr(child, (isa_get_configattr(child)|ISACFGATTR_HINTS));
 }
 
-static void
-isahint_identify(driver_t *driver, device_t parent)
+static int
+isa_match_resource_hint(device_t dev, int type, long value)
 {
-	int i;
-	static char buf[] = "isaXXX";
-	const char *dname;
-	int dunit;
-
-	/*
-	 * Add all devices configured to be attached to parent.
-	 */
-	sprintf(buf, "isa%d", device_get_unit(parent));
-	i = 0;
-	while (resource_find_match(&i, &dname, &dunit, "at", buf) == 0)
-		isahint_add_device(parent, dname, dunit);
-
-	/*
-	 * and isa?
-	 */
-	i = 0;
-	while (resource_find_match(&i, &dname, &dunit, "at", "isa") == 0)
-		isahint_add_device(parent, dname, dunit);
+	struct isa_device* idev = DEVTOISA(dev);
+	struct resource_list *rl = &idev->id_resources;
+	struct resource_list_entry *rle;
+
+	STAILQ_FOREACH(rle, rl, link) {
+		if (rle->type != type)
+			continue;
+		if (rle->start <= value && rle->end >= value)
+			return (1);
+	}
+	return (0);
 }
 
-static device_method_t isahint_methods[] = {
-	/* Device interface */
-	DEVMETHOD(device_identify,	isahint_identify),
-
-	{ 0, 0 }
-};
-
-static driver_t isahint_driver = {
-	"hint",
-	isahint_methods,
-	1,			/* no softc */
-};
-
-static devclass_t hint_devclass;
-
-DRIVER_MODULE(isahint, isa, isahint_driver, hint_devclass, 0, 0);
+void
+isa_hint_device_unit(device_t bus, device_t child, const char *name, int *unitp)
+{
+	const char *s;
+	long value;
+	int line, matches, unit;
+
+	line = 0;
+	for (;;) {
+		if (resource_find_dev(&line, name, &unit, "at", NULL) != 0)
+			break;
+
+		/* Must have an "at" for isa. */
+		resource_string_value(name, unit, "at", &s);
+		if (!(strcmp(s, device_get_nameunit(bus)) == 0 ||
+		    strcmp(s, device_get_name(bus)) == 0))
+			continue;
+
+		/*
+		 * Check for matching resources.  We must have at least one,
+		 * and all resources specified have to match.
+		 *
+		 * XXX: We may want to revisit this to be more lenient and wire
+		 * as long as it gets one match.
+		 */
+		matches = 0;
+		if (resource_long_value(name, unit, "port", &value) == 0) {
+			if (isa_match_resource_hint(child, SYS_RES_IOPORT,
+			    value))
+				matches++;
+			else
+				continue;
+		}
+		if (resource_long_value(name, unit, "maddr", &value) == 0) {
+			if (isa_match_resource_hint(child, SYS_RES_MEMORY,
+			    value))
+				matches++;
+			else
+				continue;
+		}
+		if (resource_long_value(name, unit, "irq", &value) == 0) {
+			if (isa_match_resource_hint(child, SYS_RES_IRQ, value))
+				matches++;
+			else
+				continue;
+		}
+		if (resource_long_value(name, unit, "drq", &value) == 0) {
+			if (isa_match_resource_hint(child, SYS_RES_DRQ, value))
+				matches++;
+			else
+				continue;
+		}
+
+		if (matches > 0) {
+			/* We have a winner! */
+			*unitp = unit;
+			break;
+		}
+	}
+}