Rework the ISA PnP driver pnp and the PnP resource parser to fix

the following bugs.

- When constructing a resource configuration, respect the order
  in which resource descriptors are read, in order to establish
  the correct mapping between the descriptors and configuration
  registers.
  "Plug and Play ISA Specification, Version 1.0a", Sec 4.6.1, May 5,
  1994.  "Clarifications to the Plug and Play ISA Specification,
  Version 1.0a", Sec 6.2.1, Dec. 10, 1994.

- Do not ignore null (empty) descriptors; they are valid descriptors
  acting as filler.
  "Clarifications to the Plug and Play ISA Specification, Version 1.0a",
  Sec 6.2.1.

- Correctly set up logical device configuration registers for null
  resources.
  "Clarifications to the Plug and Play ISA Specification, Version 1.0a"

- Handle null resources properly in the resource allocator for the
  ISA bus.

1 files changed, 7 insertions, 0 deletions

diff --git a/sys/isa/isavar.h b/sys/isa/isavar.h
index d81685c..fa27c3c 100644
--- a/sys/isa/isavar.h
+++ b/sys/isa/isavar.h
@@ -128,6 +128,13 @@ enum isa_device_ivars {
 };
 
 /*
+ * ISA_IVAR_CONFIGATTR bits
+ */
+#define ISACFGATTR_CANDISABLE	(1 << 0)	/* can be disabled */
+#define ISACFGATTR_DYNAMIC	(1 << 1)	/* dynamic configuration */
+#define ISACFGATTR_MULTI	(1 << 2)	/* multiple configurations */
+
+/*
  * Simplified accessors for isa devices
  */
 #define ISA_ACCESSOR(A, B, T)						\