x86, Calgary: Increase max PHB number

Newer systems (x3950M2) can have 48 PHBs per chassis and 8
chassis, so bump the limits up and provide an explanation
of the requirements for each class.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: Muli Ben-Yehuda <muli@il.ibm.com>
Cc: Corinna Schultz <cschultz@linux.vnet.ibm.com>
Cc: <stable@kernel.org>
LKML-Reference: <20100624212647.GI15515@tux1.beaverton.ibm.com>
[ v2: Fixed build bug, added back PHBS_PER_CALGARY == 4 ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/pci-calgary_64.c

@@ -103,11 +103,16 @@ int use_calgary __read_mostly = 0;
 #define PMR_SOFTSTOPFAULT	0x40000000
 #define PMR_HARDSTOP		0x20000000
 
-#define MAX_NUM_OF_PHBS		8 /* how many PHBs in total? */
-#define MAX_NUM_CHASSIS		8 /* max number of chassis */
-/* MAX_PHB_BUS_NUM is the maximal possible dev->bus->number */
-#define MAX_PHB_BUS_NUM		(MAX_NUM_OF_PHBS * MAX_NUM_CHASSIS * 2)
-#define PHBS_PER_CALGARY	4
+/*
+ * The maximum PHB bus number.
+ * x3950M2 (rare): 8 chassis, 48 PHBs per chassis = 384
+ * x3950M2: 4 chassis, 48 PHBs per chassis        = 192
+ * x3950 (PCIE): 8 chassis, 32 PHBs per chassis   = 256
+ * x3950 (PCIX): 8 chassis, 16 PHBs per chassis   = 128
+ */
+#define MAX_PHB_BUS_NUM		384
+
+#define PHBS_PER_CALGARY	  4
 
 /* register offsets in Calgary's internal register space */
 static const unsigned long tar_offsets[] = {