x86, UV: Calculate BAU destination timeout

Calculate the Broadcast Assist Unit's destination timeout period from the
values in the relevant MMR's.

Store it in each cpu's per-cpu BAU structure so that a destination
timeout can be differentiated from a 'plugged' situation in which all
software ack resources are already allocated and a timeout is pending.
That case returns an immediate destination error.

Signed-off-by: Cliff Wickman <[e-mail]>
Cc: [e-mail]
LKML-Reference: <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/include/asm/uv/uv_bau.h

···
 #define UV_ENABLE_INTD_SOFT_ACK_MODE_SHIFT 15
 #define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHIFT 16
 #define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD 0x000000000bUL
+/* [19:16] SOFT_ACK timeout period  19: 1 is urgency 7  17:16 1 is multiplier */
+#define BAU_MISC_CONTROL_MULT_MASK 3
+
+#define UVH_AGING_PRESCALE_SEL 0x000000b000UL
+/* [30:28] URGENCY_7  an index into a table of times */
+#define BAU_URGENCY_7_SHIFT 28
+#define BAU_URGENCY_7_MASK 7
+
+#define UVH_TRANSACTION_TIMEOUT 0x000000b200UL
+/* [45:40] BAU - BAU transaction timeout select - a multiplier */
+#define BAU_TRANS_SHIFT 40
+#define BAU_TRANS_MASK 0x3f
 
 /*
  * bits in UVH_LB_BAU_SB_ACTIVATION_STATUS_0/1

arch/x86/kernel/tlb_uv.c

···
 	struct bau_payload_queue_entry *va_queue_last;
 };
 
+/* timeouts in nanoseconds (indexed by UVH_AGING_PRESCALE_SEL urgency7 30:28) */
+static int timeout_base_ns[] = {
+		20,
+		160,
+		1280,
+		10240,
+		81920,
+		655360,
+		5242880,
+		167772160
+};
+static int timeout_us;
+
 #define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD	0x000000000bUL
 
 static int uv_bau_max_concurrent __read_mostly;
···
 			 * pending.  In that case hardware returns the
 			 * ERROR that looks like a destination timeout.
 			 */
-			if (cycles_2_us(ttime - bcp->send_message) < BIOS_TO) {
+			if (cycles_2_us(ttime - bcp->send_message) <
+							timeout_us) {
 				bcp->conseccompletes = 0;
 				return FLUSH_RETRY_PLUGGED;
 			}
···
 }
 
 static inline unsigned long long
-millisec_2_cycles(unsigned long millisec)
+microsec_2_cycles(unsigned long microsec)
 {
 	unsigned long ns;
 	unsigned long long cyc;
 
-	ns = millisec * 1000;
+	ns = microsec * 1000;
 	cyc = (ns << CYC2NS_SCALE_FACTOR)/(per_cpu(cyc2ns, smp_processor_id()));
 	return cyc;
 }
···
 }
 
 /*
+ * We will set BAU_MISC_CONTROL with a timeout period.
+ * But the BIOS has set UVH_AGING_PRESCALE_SEL and UVH_TRANSACTION_TIMEOUT.
+ * So the destination timeout period has be be calculated from them.
+ */
+static int
+calculate_destination_timeout(void)
+{
+	unsigned long mmr_image;
+	int mult1;
+	int mult2;
+	int index;
+	int base;
+	int ret;
+	unsigned long ts_ns;
+
+	mult1 = UV_INTD_SOFT_ACK_TIMEOUT_PERIOD & BAU_MISC_CONTROL_MULT_MASK;
+	mmr_image = uv_read_local_mmr(UVH_AGING_PRESCALE_SEL);
+	index = (mmr_image >> BAU_URGENCY_7_SHIFT) & BAU_URGENCY_7_MASK;
+	mmr_image = uv_read_local_mmr(UVH_TRANSACTION_TIMEOUT);
+	mult2 = (mmr_image >> BAU_TRANS_SHIFT) & BAU_TRANS_MASK;
+	base = timeout_base_ns[index];
+	ts_ns = base * mult1 * mult2;
+	ret = ts_ns / 1000;
+	return ret;
+}
+
+/*
  * initialize the bau_control structure for each cpu
  */
 static void uv_init_per_cpu(int nuvhubs)
···
 	};
 	struct uvhub_desc *uvhub_descs;
 
+	timeout_us = calculate_destination_timeout();
+
 	uvhub_descs = (struct uvhub_desc *)
 		kmalloc(nuvhubs * sizeof(struct uvhub_desc), GFP_KERNEL);
 	memset(uvhub_descs, 0, nuvhubs * sizeof(struct uvhub_desc));
···
 		bdp->uvhub = uvhub;
 		bdp->pnode = pnode;
 		/* time interval to catch a hardware stay-busy bug */
-		bcp->timeout_interval = millisec_2_cycles(3);
+		bcp->timeout_interval = microsec_2_cycles(2*timeout_us);
 		/* kludge: assume uv_hub.h is constant */
 		socket = (cpu_physical_id(cpu)>>5)&1;
 		if (socket >= bdp->num_sockets)