linux-kernel - [PATCH v2] powerpc/powernv: Enable cpuidle state detection for POWER11

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Message-ID: <20250908085123.216780-1-aboorvad@linux.ibm.com>
Date: Mon,  8 Sep 2025 14:21:23 +0530
From: Aboorva Devarajan <aboorvad@...ux.ibm.com>
To: maddy@...ux.ibm.com, linuxppc-dev@...ts.ozlabs.org
Cc: mahesh@...ux.ibm.com, mpe@...erman.id.au, npiggin@...il.com,
        christophe.leroy@...roup.eu, naveen@...nel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] powerpc/powernv: Enable cpuidle state detection for POWER11

Extend cpuidle state detection to POWER11 by updating the PVR check.
This ensures POWER11 correctly recognizes supported stop states,
similar to POWER9 and POWER10.

Without Patch: (Power11 - PowerNV systems)

CPUidle driver: powernv_idle
CPUidle governor: menu
analyzing CPU 927:

Number of idle states: 1
Available idle states: snooze
snooze:
Flags/Description: snooze
Latency: 0
Usage: 251631
Duration: 207497715900

--
With Patch: (Power11 - PowerNV systems)

CPUidle driver: powernv_idle
CPUidle governor: menu
analyzing CPU 959:

Number of idle states: 4
Available idle states: snooze stop0_lite stop0 stop3
snooze:
Flags/Description: snooze
Latency: 0
Usage: 2
Duration: 33
stop0_lite:
Flags/Description: stop0_lite
Latency: 1
Usage: 1
Duration: 52
stop0:
Flags/Description: stop0
Latency: 10
Usage: 13
Duration: 1920
stop3:
Flags/Description: stop3
Latency: 45
Usage: 381
Duration: 21638478

Signed-off-by: Aboorva Devarajan <aboorvad@...ux.ibm.com>

---

v1: https://lore.kernel.org/all/20250421070718.162783-1-aboorvad@linux.ibm.com/

v1 -> v2: Fixed overly permissive PVR version check as pointed out by
Christophe.

---
 arch/powerpc/platforms/powernv/idle.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index d98b933e4984..e4f4e907f6e3 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -1171,8 +1171,9 @@ static void __init pnv_arch300_idle_init(void)
 	u64 max_residency_ns = 0;
 	int i;
 
-	/* stop is not really architected, we only have p9,p10 drivers */
-	if (!pvr_version_is(PVR_POWER10) && !pvr_version_is(PVR_POWER9))
+	/* stop is not really architected, we only have p9,p10 and p11 drivers */
+	if (!pvr_version_is(PVR_POWER9) && !pvr_version_is(PVR_POWER10) &&
+		!pvr_version_is(PVR_POWER11))
 		return;
 
 	/*
@@ -1189,8 +1190,8 @@ static void __init pnv_arch300_idle_init(void)
 		struct pnv_idle_states_t *state = &pnv_idle_states[i];
 		u64 psscr_rl = state->psscr_val & PSSCR_RL_MASK;
 
-		/* No deep loss driver implemented for POWER10 yet */
-		if (pvr_version_is(PVR_POWER10) &&
+		/* No deep loss driver implemented for POWER10 and POWER11 yet */
+		if ((pvr_version_is(PVR_POWER10) || pvr_version_is(PVR_POWER11)) &&
 				state->flags & (OPAL_PM_TIMEBASE_STOP|OPAL_PM_LOSE_FULL_CONTEXT))
 			continue;
 
-- 
2.47.1