soc/mediatek/mt8188: Disable input-gating for big-core SRAM

The input-gating is an experimental feature (but unfortunately default
enabled) and would lead to crash on MT8188, so we have to disable it
in the firmware stage.

BUG=b:233720142
TEST=CPUfreq in kernel test pass.

Change-Id: Ifd68fe9362587955cdb8598c4cc5c2d0eefe53ca
Signed-off-by: Liju-Clr Chen <liju-clr.chen@mediatek.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69089
Reviewed-by: Yidi Lin <yidilin@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/soc/mediatek/mt8188/Makefile.inc

@@ -31,6 +31,7 @@ romstage-y += ../common/rtc.c ../common/rtc_osc_init.c ../common/rtc_mt6359p.c
 
 ramstage-y += ../common/auxadc.c
 ramstage-$(CONFIG_ARM64_USE_ARM_TRUSTED_FIRMWARE) += ../common/bl31.c
+ramstage-y += cpu_input_gating.c
 ramstage-y += ../common/ddp.c ddp.c
 ramstage-y += ../common/devapc.c devapc.c
 ramstage-y += ../common/dfd.c

src/soc/mediatek/mt8188/cpu_input_gating.c

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+
+#include <device/mmio.h>
+#include <soc/addressmap.h>
+#include <soc/cpu_input_gating.h>
+
+#define CPU6_IG_EN_REG	(MCUSYS_BASE + 0x3308)
+#define CPU7_IG_EN_REG	(MCUSYS_BASE + 0x3b08)
+#define DISABLE_CPU_IG	0xfc000001
+
+void disable_cpu_input_gating(void)
+{
+	write32p(CPU6_IG_EN_REG, DISABLE_CPU_IG);
+	write32p(CPU7_IG_EN_REG, DISABLE_CPU_IG);
+}

src/soc/mediatek/mt8188/include/soc/cpu_input_gating.h

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+
+#ifndef SOC_MEDIATEK_MT8188_CPU_INPUT_GATING_H
+#define SOC_MEDIATEK_MT8188_CPU_INPUT_GATING_H
+
+void disable_cpu_input_gating(void);
+
+#endif /* SOC_MEDIATEK_MT8188_CPU_INPUT_GATING_H */

src/soc/mediatek/mt8188/soc.c

@@ -3,6 +3,7 @@
 #include <bootmem.h>
 #include <console/console.h>
 #include <device/device.h>
+#include <soc/cpu_input_gating.h>
 #include <soc/devapc.h>
 #include <soc/dfd.h>
 #include <soc/dpm.h>
@@ -27,6 +28,9 @@ static void soc_read_resources(struct device *dev)
 static void soc_init(struct device *dev)
 {
 	mtk_mmu_disable_l2c_sram();
+
+	disable_cpu_input_gating();
+
 	dapc_init();
 	mcupm_init();
 	sspm_init();