diff mbox series

[V4,1/4] sensors: dts: Assert special wakeup on idle cores while reading temperature

Message ID 1511158177-19421-1-git-send-email-shilpa.bhat@linux.vnet.ibm.com
State Accepted
Headers show
Series Fixes for reading DTS sensors of cores in idle state | expand

Commit Message

Shilpasri G Bhat Nov. 20, 2017, 6:09 a.m. UTC
In P9, when a core enters a stop state, its clocks will be stopped
to save power and hence we will not be able to perform a scom
operation to read the DTS temperature sensor.  Hence, assert
a special wakeup on cores that have entered a stop state in order to
successfully complete the scom operation.

Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
[rlippert@google.com: Clear special wakeup only when it succeeds]
---
Changes from V3:
- Add per-cpu DTS timer and flag

 core/direct-controls.c |  4 +--
 core/sensor.c          |  2 +-
 hw/dts.c               | 74 +++++++++++++++++++++++++++++++++++++++++---------
 include/cpu.h          | 14 ++++++++++
 include/dts.h          |  2 +-
 5 files changed, 79 insertions(+), 17 deletions(-)
diff mbox series

Patch

diff --git a/core/direct-controls.c b/core/direct-controls.c
index 512cb36..fcb9350 100644
--- a/core/direct-controls.c
+++ b/core/direct-controls.c
@@ -220,7 +220,7 @@  static int p9_sreset_thread(struct cpu_thread *cpu)
 	return 0;
 }
 
-static int dctl_set_special_wakeup(struct cpu_thread *t)
+int dctl_set_special_wakeup(struct cpu_thread *t)
 {
 	struct cpu_thread *c = t->primary;
 	int rc = OPAL_SUCCESS;
@@ -238,7 +238,7 @@  static int dctl_set_special_wakeup(struct cpu_thread *t)
 	return rc;
 }
 
-static int dctl_clear_special_wakeup(struct cpu_thread *t)
+int dctl_clear_special_wakeup(struct cpu_thread *t)
 {
 	struct cpu_thread *c = t->primary;
 	int rc = OPAL_SUCCESS;
diff --git a/core/sensor.c b/core/sensor.c
index 57b21bc..0e2a5ca 100644
--- a/core/sensor.c
+++ b/core/sensor.c
@@ -28,7 +28,7 @@  static int64_t opal_sensor_read(uint32_t sensor_hndl, int token,
 {
 	switch (sensor_get_family(sensor_hndl)) {
 	case SENSOR_DTS:
-		return dts_sensor_read(sensor_hndl, sensor_data);
+		return dts_sensor_read(sensor_hndl, token, sensor_data);
 	case SENSOR_OCC:
 		return occ_sensor_read(sensor_hndl, sensor_data);
 	default:
diff --git a/hw/dts.c b/hw/dts.c
index a10df58..72a392b 100644
--- a/hw/dts.c
+++ b/hw/dts.c
@@ -20,6 +20,9 @@ 
 #include <dts.h>
 #include <skiboot.h>
 #include <opal-api.h>
+#include <opal-msg.h>
+#include <timer.h>
+#include <timebase.h>
 
 struct dts {
 	uint8_t		valid;
@@ -27,6 +30,14 @@  struct dts {
 	int16_t		temp;
 };
 
+/*
+ * Attributes for the core temperature sensor
+ */
+enum {
+	SENSOR_DTS_ATTR_TEMP_MAX,
+	SENSOR_DTS_ATTR_TEMP_TRIP
+};
+
 /* Different sensor locations */
 #define P7_CT_ZONE_LSU	0
 #define P7_CT_ZONE_ISU	1
@@ -225,8 +236,37 @@  static int dts_read_core_temp_p9(uint32_t pir, struct dts *dts)
 	return 0;
 }
 
-static int dts_read_core_temp(uint32_t pir, struct dts *dts)
+static void dts_async_read_temp(struct timer *t __unused, void *data,
+				u64 now __unused)
+{
+	struct dts dts;
+	int rc, swkup_rc;
+	struct cpu_thread *cpu = data;
+
+	swkup_rc = dctl_set_special_wakeup(cpu);
+
+	rc = dts_read_core_temp_p9(cpu->pir, &dts);
+	if (!rc) {
+		if (cpu->sensor_attr == SENSOR_DTS_ATTR_TEMP_MAX)
+			*(u32 *)cpu->sensor_data = dts.temp;
+		else if (cpu->sensor_attr == SENSOR_DTS_ATTR_TEMP_TRIP)
+			*(u32 *)cpu->sensor_data = dts.trip;
+	}
+
+	if (!swkup_rc)
+		dctl_clear_special_wakeup(cpu);
+
+	rc = opal_queue_msg(OPAL_MSG_ASYNC_COMP, NULL, NULL, cpu->token, rc);
+	if (rc)
+		prerror("Failed to queue async message\n");
+
+	cpu->dts_read_in_progress = false;
+}
+
+static int dts_read_core_temp(u32 pir, struct dts *dts, u8 attr,
+			      int token, u32 *sensor_data)
 {
+	struct cpu_thread *cpu;
 	int rc;
 
 	switch (proc_gen) {
@@ -236,8 +276,22 @@  static int dts_read_core_temp(uint32_t pir, struct dts *dts)
 	case proc_gen_p8:
 		rc = dts_read_core_temp_p8(pir, dts);
 		break;
-	case proc_gen_p9:
-		rc = dts_read_core_temp_p9(pir, dts);
+	case proc_gen_p9: /* Asynchronus read */
+		cpu = find_cpu_by_pir(pir);
+		if (!cpu)
+			return OPAL_PARAMETER;
+		lock(&cpu->dts_lock);
+		if (cpu->dts_read_in_progress) {
+			unlock(&cpu->dts_lock);
+			return OPAL_BUSY;
+		}
+		cpu->dts_read_in_progress = true;
+		cpu->sensor_attr = attr;
+		cpu->sensor_data = sensor_data;
+		cpu->token = token;
+		schedule_timer(&cpu->dts_timer, 0);
+		rc = OPAL_ASYNC_COMPLETION;
+		unlock(&cpu->dts_lock);
 		break;
 	default:
 		rc = OPAL_UNSUPPORTED;
@@ -303,20 +357,12 @@  enum sensor_dts_class {
 };
 
 /*
- * Attributes for the core temperature sensor
- */
-enum {
-	SENSOR_DTS_ATTR_TEMP_MAX,
-	SENSOR_DTS_ATTR_TEMP_TRIP
-};
-
-/*
  * Extract the centaur chip id which was truncated to fit in the
  * resource identifier field of the sensor handler
  */
 #define centaur_get_id(rid) (0x80000000 | ((rid) & 0x3ff))
 
-int64_t dts_sensor_read(uint32_t sensor_hndl, uint32_t *sensor_data)
+int64_t dts_sensor_read(u32 sensor_hndl, int token, u32 *sensor_data)
 {
 	uint8_t	attr = sensor_get_attr(sensor_hndl);
 	uint32_t rid = sensor_get_rid(sensor_hndl);
@@ -330,7 +376,7 @@  int64_t dts_sensor_read(uint32_t sensor_hndl, uint32_t *sensor_data)
 
 	switch (sensor_get_frc(sensor_hndl)) {
 	case SENSOR_DTS_CORE_TEMP:
-		rc = dts_read_core_temp(rid, &dts);
+		rc = dts_read_core_temp(rid, &dts, attr, token, sensor_data);
 		break;
 	case SENSOR_DTS_MEM_TEMP:
 		rc = dts_read_mem_temp(centaur_get_id(rid), &dts);
@@ -403,6 +449,8 @@  bool dts_sensor_create_nodes(struct dt_node *sensors)
 			dt_add_property_string(node, "sensor-type", "temp");
 			dt_add_property_cells(node, "ibm,pir", c->pir);
 			dt_add_property_string(node, "label", "Core");
+			init_timer(&c->dts_timer, dts_async_read_temp, c);
+			c->dts_read_in_progress = false;
 		}
 	}
 
diff --git a/include/cpu.h b/include/cpu.h
index 168fa99..d4b7a42 100644
--- a/include/cpu.h
+++ b/include/cpu.h
@@ -23,6 +23,7 @@ 
 #include <device.h>
 #include <opal.h>
 #include <stack.h>
+#include <timer.h>
 
 /*
  * cpu_thread is our internal structure representing each
@@ -102,6 +103,16 @@  struct cpu_thread {
 	struct lock			dctl_lock; /* primary only */
 	bool				dctl_stopped; /* per thread */
 	uint32_t			special_wakeup_count; /* primary */
+
+	/*
+	 * For reading DTS sensors async
+	 */
+	struct lock			dts_lock;
+	struct timer			dts_timer;
+	void				*sensor_data;
+	u32				sensor_attr;
+	u32				token;
+	bool				dts_read_in_progress;
 };
 
 /* This global is set to 1 to allow secondaries to callin,
@@ -284,4 +295,7 @@  extern void cpu_idle_delay(unsigned long delay);
 extern void cpu_set_radix_mode(void);
 extern void cpu_fast_reboot_complete(void);
 
+int dctl_set_special_wakeup(struct cpu_thread *t);
+int dctl_clear_special_wakeup(struct cpu_thread *t);
+
 #endif /* __CPU_H */
diff --git a/include/dts.h b/include/dts.h
index b37919f..17e2e15 100644
--- a/include/dts.h
+++ b/include/dts.h
@@ -19,7 +19,7 @@ 
 
 #include <stdint.h>
 
-extern int64_t dts_sensor_read(uint32_t sensor_hndl, uint32_t *sensor_data);
+extern int64_t dts_sensor_read(u32 sensor_hndl, int token, u32 *sensor_data);
 extern bool dts_sensor_create_nodes(struct dt_node *sensors);
 
 #endif /* __DTS_H */