From: Paul Mackerras <paulus@ozlabs.org>
Date: Fri, 31 Jan 2025 06:28:39 +0000 (+1100)
Subject: powerpc/microwatt: Define an idle power-save function
X-Git-Tag: v6.15-rc1~133^2~8
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2b0a438d5380c32817e1b2c883bd0494461e9f4f;p=thirdparty%2Fkernel%2Flinux.git

powerpc/microwatt: Define an idle power-save function

This uses the 'wait' instruction to pause instruction execution when
idle until an interrupt occurs.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/Z5xtl1m_Gqc-HLjY@thinks.paulus.ozlabs.org
---

diff --git a/arch/powerpc/platforms/microwatt/setup.c b/arch/powerpc/platforms/microwatt/setup.c
index 5e1c0997170dc..a942c446aeab8 100644
--- a/arch/powerpc/platforms/microwatt/setup.c
+++ b/arch/powerpc/platforms/microwatt/setup.c
@@ -34,10 +34,19 @@ static void __init microwatt_setup_arch(void)
 	microwatt_rng_init();
 }
 
+static void microwatt_idle(void)
+{
+	if (!prep_irq_for_idle_irqsoff())
+		return;
+
+	__asm__ __volatile__ ("wait");
+}
+
 define_machine(microwatt) {
 	.name			= "microwatt",
 	.compatible		= "microwatt-soc",
 	.init_IRQ		= microwatt_init_IRQ,
 	.setup_arch		= microwatt_setup_arch,
 	.progress		= udbg_progress,
+	.power_save		= microwatt_idle,
 };