acpigen: Add a runtime method to override exposed _Sx sleep states

This allows mainboards to override available sleep states at runtime.
This is done by adding a IntObj in SSDT that DSDT consumes to override
the available _Sx states.

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: Ic21830c1ef9c183b1e3005cc1f8b7daf7e9ea998
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74762
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Jakub Czapiga <jacz@semihalf.com>
Reviewed-by: Jan Samek <jan.samek@siemens.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>

src/acpi/acpigen.c

@@ -2364,3 +2364,17 @@ void acpigen_write_delay_until_namestr_int(uint32_t wait_ms, const char *name, u
 	acpigen_emit_byte(LOCAL7_OP);
 	acpigen_pop_len(); /* While */
 }
+
+void acpigen_ssdt_override_sleep_states(bool enable_s1, bool enable_s2, bool enable_s3,
+					bool enable_s4)
+{
+	assert(!(enable_s1 && CONFIG(ACPI_S1_NOT_SUPPORTED)));
+	assert(!(enable_s3 && !CONFIG(HAVE_ACPI_RESUME)));
+	assert(!(enable_s4 && CONFIG(DISABLE_ACPI_HIBERNATE)));
+
+	acpigen_write_scope("\\");
+	uint32_t sleep_enable = (enable_s1 << 0) | (enable_s2 << 1)
+		| (enable_s3 << 2) | (enable_s4 << 3);
+	acpigen_write_name_dword("OSFG", sleep_enable);
+	acpigen_pop_len();
+}

src/include/acpi/acpigen.h

@@ -695,4 +695,8 @@ void acpigen_resource_qword(u16 res_type, u16 gen_flags, u16 type_flags,
 /* Emits Notify(namestr, value) */
 void acpigen_notify(const char *namestr, int value);
 
+/* Create a namespace \OSFG to override the enabled sleep states */
+void acpigen_ssdt_override_sleep_states(bool enable_s1, bool enable_s2, bool enable_s3,
+					bool enable_s4);
+
 #endif /* __ACPI_ACPIGEN_H__ */

src/southbridge/intel/common/acpi/sleepstates.asl

@@ -15,6 +15,11 @@ If (CONFIG(DISABLE_ACPI_HIBERNATE)) {
 	SSFG &= 0xf7
 }
 
+External (\OSFG, IntObj)
+If (CondRefOf(\OSFG)) {
+	SSFG = \OSFG
+}
+
 /* Supported sleep states: */
 Name(\_S0, Package () {0x00, 0x00, 0x00, 0x00} )	/* (S0) - working state */