[Skiboot] [RFC 4/4] SLW: Enable Stop4 as the deepest idle state

[Akshay Adiga]

Adding stop4 to device tree as the deepest idle state for power9 dd1.
The latency is choosen such that they are not chosen for cpuidle and
will only be used for cpuhotplug.

Use a common variable has_wakeup_engine instead of has_slw to tell if
the
a) SLW image is populated in case of power8
b) CME image is populated in case of power9

Currently we expect CME to be loaded if homer address is known ( except
for simulators)

Signed-off-by: Akshay Adiga <akshay.adiga at linux.vnet.ibm.com>
---
 hw/slw.c | 29 ++++++++++++++++++++++++-----
 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/hw/slw.c b/hw/slw.c
index aeb8388..93d5aae 100644
--- a/hw/slw.c
+++ b/hw/slw.c
@@ -700,6 +700,22 @@ static struct cpu_idle_states power9_dd1_cpu_idle_states[] = {
 				 | OPAL_PM_PSSCR_TR(3) \
 				 | OPAL_PM_PSSCR_ESL \
 				 | OPAL_PM_PSSCR_EC,
+		.pm_ctrl_reg_mask = OPAL_PM_PSSCR_MASK },
+	{
+		.name = "stop4",
+		.latency_ns = 2060000,
+		.residency_ns = 1000000,
+		.flags = 1*OPAL_PM_DEC_STOP \
+		       | 1*OPAL_PM_TIMEBASE_STOP  \
+		       | 1*OPAL_PM_LOSE_USER_CONTEXT \
+		       | 1*OPAL_PM_LOSE_HYP_CONTEXT \
+		       | 1*OPAL_PM_LOSE_FULL_CONTEXT \
+		       | 1*OPAL_PM_STOP_INST_DEEP,
+		.pm_ctrl_reg_val = OPAL_PM_PSSCR_RL(4) \
+				 | OPAL_PM_PSSCR_MTL(7) \
+				 | OPAL_PM_PSSCR_TR(3) \
+				 | OPAL_PM_PSSCR_ESL \
+				 | OPAL_PM_PSSCR_EC,
 		.pm_ctrl_reg_mask = OPAL_PM_PSSCR_MASK }
 };
 
@@ -712,7 +728,7 @@ void add_cpu_idle_state_properties(void)
 	int nr_states;
 
 	bool can_sleep = true;
-	bool has_slw = true;
+	bool has_wakeup_engine = true;	/* p8=SLW; p9=CME */
 	bool has_stop_inst = false;
 	u8 i;
 
@@ -802,8 +818,11 @@ void add_cpu_idle_state_properties(void)
 	}
 
 	/* Enable deep idle states only if slw image is intact */
-	has_slw = (chip->slw_base && chip->slw_bar_size &&
-			chip->slw_image_size);
+	if (proc_gen == proc_gen_p8)
+		has_wakeup_engine = (chip->slw_base && chip->slw_bar_size &&
+				chip->slw_image_size);
+	else /*if (proc_gen == proc_gen_p9)*/
+		has_wakeup_engine = !(QUIRK_MAMBO_CALLOUTS);
 
 	/*
 	 * Currently we can't append strings and cells to dt properties.
@@ -831,7 +850,7 @@ void add_cpu_idle_state_properties(void)
 	if (has_stop_inst) {
 		/* Power 9 / POWER ISA 3.0 */
 		supported_states_mask = OPAL_PM_STOP_INST_FAST;
-		if (has_slw)
+		if (has_wakeup_engine)
 			supported_states_mask |= OPAL_PM_STOP_INST_DEEP;
 	} else {
 		/* Power 7 and Power 8 */
@@ -839,7 +858,7 @@ void add_cpu_idle_state_properties(void)
 		if (can_sleep)
 			supported_states_mask |= OPAL_PM_SLEEP_ENABLED |
 						OPAL_PM_SLEEP_ENABLED_ER1;
-		if (has_slw)
+		if (has_wakeup_engine)
 			supported_states_mask |= OPAL_PM_WINKLE_ENABLED;
 	}
 	for (i = 0; i < nr_states; i++) {
-- 
2.5.5