linux-kernel - [PATCH] powerpc/powernv: Enable CPU idle state detection for POWER11

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Message-ID: <20250421070718.162783-1-aboorvad@linux.ibm.com>
Date: Mon, 21 Apr 2025 12:37:18 +0530
From: Aboorva Devarajan <aboorvad@...ux.ibm.com>
To: Madhavan Srinivasan <maddy@...ux.ibm.com>, linuxppc-dev@...ts.ozlabs.org
Cc: Mahesh Salgaonkar <mahesh@...ux.ibm.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Naveen N Rao <naveen@...nel.org>,
        Aboorva Devarajan <aboorvad@...ux.ibm.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc/powernv: Enable CPU idle state detection for POWER11

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

Reviewed-by: Mahesh Salgaonkar <mahesh@...ux.ibm.com>
Signed-off-by: Aboorva Devarajan <aboorvad@...ux.ibm.com>

---

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


 arch/powerpc/platforms/powernv/idle.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
index d98b933e4984..10f4d7d5eb44 100644
--- a/arch/powerpc/platforms/powernv/idle.c
+++ b/arch/powerpc/platforms/powernv/idle.c
@@ -1171,8 +1171,8 @@ 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_VER(mfspr(SPRN_PVR)) >= PVR_POWER9))
 		return;
 
 	/*
@@ -1189,8 +1189,8 @@ 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_VER(mfspr(SPRN_PVR)) >= PVR_POWER10) &&
 				state->flags & (OPAL_PM_TIMEBASE_STOP|OPAL_PM_LOSE_FULL_CONTEXT))
 			continue;
 
-- 
2.49.0