powerpc/pseries: Limit EPOW reset event warnings

Kernel prints respective warnings about various EPOW events for
user information/action after parsing EPOW interrupts. At times
below EPOW reset event warning is seen to be flooding kernel log
over a period of time.

May 25 03:46:34 alp kernel: Non critical power or cooling issue cleared
May 25 03:46:52 alp kernel: Non critical power or cooling issue cleared
May 25 03:53:48 alp kernel: Non critical power or cooling issue cleared
May 25 03:55:46 alp kernel: Non critical power or cooling issue cleared
May 25 03:56:34 alp kernel: Non critical power or cooling issue cleared
May 25 03:59:04 alp kernel: Non critical power or cooling issue cleared
May 25 04:02:01 alp kernel: Non critical power or cooling issue cleared

These EPOW reset events are spurious in nature and are triggered by
firmware without an actual EPOW event being reset. This patch avoids these
multiple EPOW reset warnings by using a counter variable. This variable
is incremented every time an EPOW event is reported. Upon receiving a EPOW
reset event the same variable is checked to filter out spurious events and
decremented accordingly.

This patch also improves log messages to better describe EPOW event being
reported. Merged adjacent log messages into single one to reduce number of
lines printed per event.
Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Vipin K Parashar <vipin@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pseries/ras.c

@@ -40,6 +40,9 @@ static int ras_check_exception_token;
 #define EPOW_SENSOR_TOKEN	9
 #define EPOW_SENSOR_INDEX	0
 
+/* EPOW events counter variable */
+static int num_epow_events;
+
 static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
 static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
 
@@ -82,32 +85,30 @@ static void handle_system_shutdown(char event_modifier)
 {
 	switch (event_modifier) {
 	case EPOW_SHUTDOWN_NORMAL:
-		pr_emerg("Firmware initiated power off");
+		pr_emerg("Power off requested\n");
 		orderly_poweroff(true);
 		break;
 
 	case EPOW_SHUTDOWN_ON_UPS:
-		pr_emerg("Loss of power reported by firmware, system is "
-			"running on UPS/battery");
-		pr_emerg("Check RTAS error log for details");
+		pr_emerg("Loss of system power detected. System is running on"
+			 " UPS/battery. Check RTAS error log for details\n");
 		orderly_poweroff(true);
 		break;
 
 	case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
-		pr_emerg("Loss of system critical functions reported by "
-			"firmware");
-		pr_emerg("Check RTAS error log for details");
+		pr_emerg("Loss of system critical functions detected. Check"
+			 " RTAS error log for details\n");
 		orderly_poweroff(true);
 		break;
 
 	case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
-		pr_emerg("Ambient temperature too high reported by firmware");
-		pr_emerg("Check RTAS error log for details");
+		pr_emerg("High ambient temperature detected. Check RTAS"
+			 " error log for details\n");
 		orderly_poweroff(true);
 		break;
 
 	default:
-		pr_err("Unknown power/cooling shutdown event (modifier %d)",
+		pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
 			event_modifier);
 	}
 }
@@ -145,17 +146,20 @@ static void rtas_parse_epow_errlog(struct rtas_error_log *log)
 
 	switch (action_code) {
 	case EPOW_RESET:
-		pr_err("Non critical power or cooling issue cleared");
+		if (num_epow_events) {
+			pr_info("Non critical power/cooling issue cleared\n");
+			num_epow_events--;
+		}
 		break;
 
 	case EPOW_WARN_COOLING:
-		pr_err("Non critical cooling issue reported by firmware");
-		pr_err("Check RTAS error log for details");
+		pr_info("Non-critical cooling issue detected. Check RTAS error"
+			" log for details\n");
 		break;
 
 	case EPOW_WARN_POWER:
-		pr_err("Non critical power issue reported by firmware");
-		pr_err("Check RTAS error log for details");
+		pr_info("Non-critical power issue detected. Check RTAS error"
+			" log for details\n");
 		break;
 
 	case EPOW_SYSTEM_SHUTDOWN:
@@ -163,23 +167,27 @@ static void rtas_parse_epow_errlog(struct rtas_error_log *log)
 		break;
 
 	case EPOW_SYSTEM_HALT:
-		pr_emerg("Firmware initiated power off");
+		pr_emerg("Critical power/cooling issue detected. Check RTAS"
+			 " error log for details. Powering off.\n");
 		orderly_poweroff(true);
 		break;
 
 	case EPOW_MAIN_ENCLOSURE:
 	case EPOW_POWER_OFF:
-		pr_emerg("Critical power/cooling issue reported by firmware");
-		pr_emerg("Check RTAS error log for details");
-		pr_emerg("Immediate power off");
+		pr_emerg("System about to lose power. Check RTAS error log "
+			 " for details. Powering off immediately.\n");
 		emergency_sync();
 		kernel_power_off();
 		break;
 
 	default:
-		pr_err("Unknown power/cooling event (action code %d)",
+		pr_err("Unknown power/cooling event (action code  = %d)\n",
 			action_code);
 	}
+
+	/* Increment epow events counter variable */
+	if (action_code != EPOW_RESET)
+		num_epow_events++;
 }
 
 /* Handle environmental and power warning (EPOW) interrupts. */
@@ -249,13 +257,12 @@ static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
 	log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);
 
 	if (fatal) {
-		pr_emerg("Fatal hardware error reported by firmware");
-		pr_emerg("Check RTAS error log for details");
-		pr_emerg("Immediate power off");
+		pr_emerg("Fatal hardware error detected. Check RTAS error"
+			 " log for details. Powering off immediately\n");
 		emergency_sync();
 		kernel_power_off();
 	} else {
-		pr_err("Recoverable hardware error reported by firmware");
+		pr_err("Recoverable hardware error detected\n");
 	}
 
 	spin_unlock(&ras_log_buf_lock);