MFp4: Large set of CAM inprovements.

- Unify bus reset/probe sequence. Whenever bus attached at boot or later,
CAM will automatically reset and scan it. It allows to remove duplicate
code from many drivers.
- Any bus, attached before CAM completed it's boot-time initialization,
will equally join to the process, delaying boot if needed.
- New kern.cam.boot_delay loader tunable should help controllers that
are still unable to register their buses in time (such as slow USB/
PCCard/ CardBus devices), by adding one more event to wait on boot.
- To allow synchronization between different CAM levels, concept of
requests priorities was extended. Priorities now split between several
"run levels". Device can be freezed at specified level, allowing higher
priority requests to pass. For example, no payload requests allowed,
until PMP driver enable port. ATA XPT negotiate transfer parameters,
periph driver configure caching and so on.
- Frozen requests are no more counted by request allocation scheduler.
It fixes deadlocks, when frozen low priority payload requests occupying
slots, required by higher levels to manage theit execution.
- Two last changes were holding proper ATA reinitialization and error
recovery implementation. Now it is done: SATA controllers and Port
Multipliers now implement automatic hot-plug and should correctly
recover from timeouts and bus resets.
- Improve SCSI error recovery for devices on buses without automatic sense
reporting, such as ATAPI or USB. For example, it allows CAM to wait, while
CD drive loads disk, instead of immediately return error status.
- Decapitalize diagnostic messages and make them more readable and sensible.
- Teach PMP driver to limit maximum speed on fan-out ports.
- Make boot wait for PMP scan completes, and make rescan more reliable.
- Fix pass driver, to return CCB to user level in case of error.
- Increase number of retries in cd driver, as device may return several UAs.

1 files changed, 19 insertions, 6 deletions

diff --git a/sys/cam/cam.h b/sys/cam/cam.h
index 3d85264..2b3b98c 100644
--- a/sys/cam/cam.h
+++ b/sys/cam/cam.h
@@ -60,16 +60,29 @@ typedef u_int lun_id_t;
 struct cam_periph;
 
 /*
- * Priority information for a CAM structure.  The generation number is
- * incremented everytime a new entry is entered into the queue giving round
- * robin per priority level scheduling.
+ * Priority information for a CAM structure. 
+ */
+typedef enum {
+    CAM_RL_HOST,
+    CAM_RL_BUS,
+    CAM_RL_XPT,
+    CAM_RL_DEV,
+    CAM_RL_NORMAL,
+    CAM_RL_VALUES
+} cam_rl;
+/*
+ * The generation number is incremented everytime a new entry is entered into
+ * the queue giving round robin per priority level scheduling.
  */
 typedef struct {
 	u_int32_t priority;
-#define CAM_PRIORITY_BUS	0
-#define CAM_PRIORITY_DEV	0
-#define CAM_PRIORITY_NORMAL	1
+#define CAM_PRIORITY_HOST	((CAM_RL_HOST << 8) + 0x80)
+#define CAM_PRIORITY_BUS	((CAM_RL_BUS << 8) + 0x80)
+#define CAM_PRIORITY_XPT	((CAM_RL_XPT << 8) + 0x80)
+#define CAM_PRIORITY_DEV	((CAM_RL_DEV << 8) + 0x80)
+#define CAM_PRIORITY_NORMAL	((CAM_RL_NORMAL << 8) + 0x80)
 #define CAM_PRIORITY_NONE	(u_int32_t)-1
+#define CAM_PRIORITY_TO_RL(x)	((x) >> 8)
 	u_int32_t generation;
 	int       index;
 #define CAM_UNQUEUED_INDEX	-1