From 0f2942b513ab38e06cb29c740d36756159e572d7 Mon Sep 17 00:00:00 2001
From: Zhigang Qin <zhigang.qin@mediatek.corp-partner.google.com>
Date: Thu, 13 Mar 2025 16:29:32 +0800
Subject: [PATCH] mb/google/skywalker: Raise little core CPU frequency to 2.0
 GHz
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Increase the CPU little core frequency from 1.6 GHz to 2.0 GHz to
speed up the boot process.

BUG=b:379008996
BRANCH=none
TEST=check little core cpu frequency is 2GHz in kernel by commands
clkdbg() { echo $@ > /proc/clkdbg ; cat /proc/clkdbg ; }
clkdbg fmeter

See the little core CPU frequency:
fm_armpll_ll_ck          	: 1999968

Signed-off-by: Zhigang Qin <zhigang.qin@mediatek.corp-partner.google.com>
Change-Id: I979f44e9340ea5bd733dc7f0fe47af47a4f403b7
Reviewed-on: https://review.coreboot.org/c/coreboot/+/87795
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Yidi Lin <yidilin@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
---
 src/mainboard/google/skywalker/romstage.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/mainboard/google/skywalker/romstage.c b/src/mainboard/google/skywalker/romstage.c
index 1ba948ee9e..3b6de958d1 100644
--- a/src/mainboard/google/skywalker/romstage.c
+++ b/src/mainboard/google/skywalker/romstage.c
@@ -1,17 +1,30 @@
 /* SPDX-License-Identifier: GPL-2.0-only OR MIT */
 
 #include <arch/stages.h>
+#include <delay.h>
 #include <soc/emi.h>
 #include <soc/mt6315.h>
 #include <soc/mt6359p.h>
+#include <soc/pll.h>
 #include <soc/pmif.h>
+#include <soc/regulator.h>
 #include <soc/rtc.h>
 
+static void raise_little_cpu_freq(void)
+{
+	mainboard_set_regulator_voltage(MTK_REGULATOR_VSRAM_PROC12, 1050000);
+	mainboard_set_regulator_voltage(MTK_REGULATOR_VPROC12, 1050000);
+	udelay(200);
+	mt_pll_raise_little_cpu_freq(2000 * MHz);
+	mt_pll_raise_cci_freq(1540 * MHz);
+}
+
 void platform_romstage_main(void)
 {
 	mtk_pmif_init();
 	mt6315_init();
 	mt6359p_init();
+	raise_little_cpu_freq();
 	rtc_boot();
 	mtk_dram_init();
 }