mb/google/brya: Remove mainboard.asl

Use C code to generate MS0X entry and provide variant hook.

BUG=b:207144468
TEST=check SSDT table has the same entry.
    Scope (\_SB)
    {
        Method (MS0X, 1, Serialized)
        {
            If ((Arg0 == One))
            {
                \_SB.PCI0.CTXS (0x148)
            }
            Else
            {
                \_SB.PCI0.STXS (0x148)
            }
        }
    }

Signed-off-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Change-Id: Ic36543e5cbaf8aaa7d933dcf54badc5f40e8ef02
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62779
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kangheui Won <khwon@chromium.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
diff --git a/src/mainboard/google/brya/dsdt.asl b/src/mainboard/google/brya/dsdt.asl
index fed071b..82cafcf 100644
--- a/src/mainboard/google/brya/dsdt.asl
+++ b/src/mainboard/google/brya/dsdt.asl
@@ -22,7 +22,6 @@
 	#include <cpu/intel/common/acpi/cpu.asl>
 
 	Scope (\_SB) {
-		#include "mainboard.asl"
 #if CONFIG(HAVE_WWAN_POWER_SEQUENCE)
 		#include "wwan_power.asl"
 #endif
diff --git a/src/mainboard/google/brya/mainboard.asl b/src/mainboard/google/brya/mainboard.asl
deleted file mode 100644
index 8ca694d..0000000
--- a/src/mainboard/google/brya/mainboard.asl
+++ /dev/null
@@ -1,26 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#include <baseboard/gpio.h>
-
-#if CONFIG(HAVE_SLP_S0_GATE)
-/*
- * S0ix Entry/Exit Notifications
- * Called from \_SB.PEPD._DSM
- */
-Method (MS0X, 1, Serialized)
-{
-	If (Arg0 == 1) {
-		/*
-		 * On S0ix entry, clear the SLP_S0_GATE pin, so that the rest of
-		 * the platform can transition to its low power state as well.
-		 */
-		\_SB.PCI0.CTXS(GPIO_SLP_S0_GATE);
-	} Else {
-		/*
-		 * On S0ix exit, set the SLP_S0_GATE pin, so that the rest of
-		 * the platform will resume from its low power state.
-		 */
-		\_SB.PCI0.STXS(GPIO_SLP_S0_GATE);
-	}
-}
-#endif
diff --git a/src/mainboard/google/brya/mainboard.c b/src/mainboard/google/brya/mainboard.c
index 42536bb..b3f42ca 100644
--- a/src/mainboard/google/brya/mainboard.c
+++ b/src/mainboard/google/brya/mainboard.c
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
 #include <acpi/acpigen.h>
+#include <baseboard/gpio.h>
 #include <baseboard/variants.h>
 #include <device/device.h>
 #include <drivers/tpm/cr50.h>
@@ -109,6 +110,23 @@
 	}
 }
 
+static void mainboard_generate_s0ix_hook(void)
+{
+	acpigen_write_if_lequal_op_int(ARG0_OP, 1);
+	{
+		if (CONFIG(HAVE_SLP_S0_GATE))
+			acpigen_soc_clear_tx_gpio(GPIO_SLP_S0_GATE);
+		variant_generate_s0ix_hook(S0IX_ENTRY);
+	}
+	acpigen_write_else();
+	{
+		if (CONFIG(HAVE_SLP_S0_GATE))
+			acpigen_soc_set_tx_gpio(GPIO_SLP_S0_GATE);
+		variant_generate_s0ix_hook(S0IX_EXIT);
+	}
+	acpigen_write_if_end();
+}
+
 static void mainboard_fill_ssdt(const struct device *dev)
 {
 	const struct device *wwan = DEV_PTR(rp6_wwan);
@@ -122,6 +140,13 @@
 	}
 	/* for variant to fill additional SSDT */
 	variant_fill_ssdt(dev);
+
+	acpigen_write_scope("\\_SB");
+	acpigen_write_method_serialized("MS0X", 1);
+	mainboard_generate_s0ix_hook();
+	acpigen_write_method_end(); /* Method */
+	acpigen_write_scope_end(); /* Scope */
+
 }
 
 void __weak variant_fill_ssdt(const struct device *dev)
@@ -129,6 +154,19 @@
 	/* Add board-specific SSDT entries */
 }
 
+void __weak variant_generate_s0ix_hook(enum s0ix_entry)
+{
+	/* Add board-specific MS0X entries */
+	/*
+	   if (s0ix_entry == S0IX_ENTRY) {
+		implement variant operations here
+	   }
+	   if (s0ix_entry == S0IX_EXIT) {
+		implement variant operations here
+	   }
+	 */
+}
+
 static void mainboard_enable(struct device *dev)
 {
 	dev->ops->init = mainboard_dev_init;
diff --git a/src/mainboard/google/brya/variants/baseboard/include/baseboard/variants.h b/src/mainboard/google/brya/variants/baseboard/include/baseboard/variants.h
index 7c1ce21..9accc08 100644
--- a/src/mainboard/google/brya/variants/baseboard/include/baseboard/variants.h
+++ b/src/mainboard/google/brya/variants/baseboard/include/baseboard/variants.h
@@ -25,6 +25,13 @@
 void variant_update_soc_chip_config(struct soc_intel_alderlake_config *config);
 void variant_fill_ssdt(const struct device *dev);
 
+enum s0ix_entry {
+	S0IX_EXIT,
+	S0IX_ENTRY,
+};
+
+void variant_generate_s0ix_hook(enum s0ix_entry);
+
 /* Modify devictree settings during ramstage */
 void variant_devtree_update(void);
 
diff --git a/src/mainboard/google/brya/variants/baseboard/nissa/include/baseboard/gpio.h b/src/mainboard/google/brya/variants/baseboard/nissa/include/baseboard/gpio.h
index 068aaa4..51e4b20 100644
--- a/src/mainboard/google/brya/variants/baseboard/nissa/include/baseboard/gpio.h
+++ b/src/mainboard/google/brya/variants/baseboard/nissa/include/baseboard/gpio.h
@@ -16,5 +16,7 @@
 #define GPIO_EC_IN_RW		GPP_F18
 /* GPIO IRQ for tight timestamps */
 #define EC_SYNC_IRQ		GPD2_IRQ
+/* GPP_H18 used as dummy here since nissa not selected HAVE_SLP_S0_GATE */
+#define GPIO_SLP_S0_GATE	GPP_H18
 
 #endif /* __BASEBOARD_GPIO_H__ */