[030/108] acpi: Add functions to generate ACPI code

diff --git a/include/acpigen.h b/include/acpigen.h
new file mode 100644
index 0000000000..08000831b9
--- /dev/null
+++ b/include/acpigen.h
@@ -0,0 +1,482 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Core ACPI (Advanced Configuration and Power Interface) support
+ *
+ * Copyright 2019 Google LLC
+ *
+ * Modified from coreboot file acpigen.h
+ */
+
+#ifndef _ACPIGEN_H
+#define _ACPIGEN_H
+
+#include <acpi_table.h>
+
+struct acpi_cstate;
+struct acpi_pld;
+struct acpi_gpio;
+struct acpi_tstate;
+
+/* Values that can be returned for ACPI Device _STA method */
+#define ACPI_STATUS_DEVICE_PRESENT	BIT(0)
+#define ACPI_STATUS_DEVICE_ENABLED	BIT(1)
+#define ACPI_STATUS_DEVICE_SHOW_IN_UI	BIT(2)
+#define ACPI_STATUS_DEVICE_STATE_OK	BIT(3)
+
+#define ACPI_STATUS_DEVICE_ALL_OFF	0
+#define ACPI_STATUS_DEVICE_ALL_ON	(ACPI_STATUS_DEVICE_PRESENT |\
+					 ACPI_STATUS_DEVICE_ENABLED |\
+					 ACPI_STATUS_DEVICE_SHOW_IN_UI |\
+					 ACPI_STATUS_DEVICE_STATE_OK)
+#define ACPI_STATUS_DEVICE_HIDDEN_ON	(ACPI_STATUS_DEVICE_PRESENT |\
+					 ACPI_STATUS_DEVICE_ENABLED |\
+					 ACPI_STATUS_DEVICE_STATE_OK)
+
+/* ACPI Op/Prefix Codes */
+enum {
+	ZERO_OP			= 0x00,
+	ONE_OP			= 0x01,
+	ALIAS_OP		= 0x06,
+	NAME_OP			= 0x08,
+	BYTE_PREFIX		= 0x0A,
+	WORD_PREFIX		= 0x0B,
+	DWORD_PREFIX		= 0x0C,
+	STRING_PREFIX		= 0x0D,
+	QWORD_PREFIX		= 0x0E,
+	SCOPE_OP		= 0x10,
+	BUFFER_OP		= 0x11,
+	PACKAGE_OP		= 0x12,
+	VARIABLE_PACKAGE_OP	= 0x13,
+	METHOD_OP		= 0x14,
+	EXTERNAL_OP		= 0x15,
+	DUAL_NAME_PREFIX	= 0x2E,
+	MULTI_NAME_PREFIX	= 0x2F,
+	EXT_OP_PREFIX		= 0x5B,
+
+	MUTEX_OP		= 0x01,
+	EVENT_OP		= 0x01,
+	SF_RIGHT_OP		= 0x10,
+	SF_LEFT_OP		= 0x11,
+	COND_REFOF_OP		= 0x12,
+	CREATEFIELD_OP		= 0x13,
+	LOAD_TABLE_OP		= 0x1f,
+	LOAD_OP		= 0x20,
+	STALL_OP		= 0x21,
+	SLEEP_OP		= 0x22,
+	ACQUIRE_OP		= 0x23,
+	SIGNAL_OP		= 0x24,
+	WAIT_OP		= 0x25,
+	RST_OP			= 0x26,
+	RELEASE_OP		= 0x27,
+	FROM_BCD_OP		= 0x28,
+	TO_BCD_OP		= 0x29,
+	UNLOAD_OP		= 0x2A,
+	REVISON_OP		= 0x30,
+	DEBUG_OP		= 0x31,
+	FATAL_OP		= 0x32,
+	TIMER_OP		= 0x33,
+	OPREGION_OP		= 0x80,
+	FIELD_OP		= 0x81,
+	DEVICE_OP		= 0x82,
+	PROCESSOR_OP		= 0x83,
+	POWER_RES_OP		= 0x84,
+	THERMAL_ZONE_OP	= 0x85,
+	INDEX_FIELD_OP		= 0x86,
+	BANK_FIELD_OP		= 0x87,
+	DATA_REGION_OP		= 0x88,
+
+	ROOT_PREFIX		= 0x5C,
+	PARENT_PREFIX		= 0x5D,
+	LOCAL0_OP		= 0x60,
+	LOCAL1_OP		= 0x61,
+	LOCAL2_OP		= 0x62,
+	LOCAL3_OP		= 0x63,
+	LOCAL4_OP		= 0x64,
+	LOCAL5_OP		= 0x65,
+	LOCAL6_OP		= 0x66,
+	LOCAL7_OP		= 0x67,
+	ARG0_OP			= 0x68,
+	ARG1_OP			= 0x69,
+	ARG2_OP			= 0x6A,
+	ARG3_OP			= 0x6B,
+	ARG4_OP			= 0x6C,
+	ARG5_OP			= 0x6D,
+	ARG6_OP			= 0x6E,
+	STORE_OP		= 0x70,
+	REF_OF_OP		= 0x71,
+	ADD_OP			= 0x72,
+	CONCATENATE_OP		= 0x73,
+	SUBTRACT_OP		= 0x74,
+	INCREMENT_OP		= 0x75,
+	DECREMENT_OP		= 0x76,
+	MULTIPLY_OP		= 0x77,
+	DIVIDE_OP		= 0x78,
+	SHIFT_LEFT_OP		= 0x79,
+	SHIFT_RIGHT_OP		= 0x7A,
+	AND_OP			= 0x7B,
+	NAND_OP			= 0x7C,
+	OR_OP			= 0x7D,
+	NOR_OP			= 0x7E,
+	XOR_OP			= 0x7F,
+	NOT_OP			= 0x80,
+	FD_SHIFT_LEFT_BIT_OR	= 0x81,
+	FD_SHIFT_RIGHT_BIT_OR	= 0x82,
+	DEREF_OP		= 0x83,
+	CONCATENATE_TEMP_OP	= 0x84,
+	MOD_OP			= 0x85,
+	NOTIFY_OP		= 0x86,
+	SIZEOF_OP		= 0x87,
+	INDEX_OP		= 0x88,
+	MATCH_OP		= 0x89,
+	CREATE_DWORD_OP		= 0x8A,
+	CREATE_WORD_OP		= 0x8B,
+	CREATE_BYTE_OP		= 0x8C,
+	CREATE_BIT_OP		= 0x8D,
+	OBJ_TYPE_OP		= 0x8E,
+	CREATE_QWORD_OP		= 0x8F,
+	LAND_OP			= 0x90,
+	LOR_OP			= 0x91,
+	LNOT_OP			= 0x92,
+	LEQUAL_OP		= 0x93,
+	LGREATER_OP		= 0x94,
+	LLESS_OP		= 0x95,
+	TO_BUFFER_OP		= 0x96,
+	TO_DEC_STRING_OP	= 0x97,
+	TO_HEX_STRING_OP	= 0x98,
+	TO_INTEGER_OP		= 0x99,
+	TO_STRING_OP		= 0x9C,
+	CP_OBJ_OP		= 0x9D,
+	MID_OP			= 0x9E,
+	CONTINUE_OP		= 0x9F,
+	IF_OP			= 0xA0,
+	ELSE_OP			= 0xA1,
+	WHILE_OP		= 0xA2,
+	NOOP_OP			= 0xA3,
+	RETURN_OP		= 0xA4,
+	BREAK_OP		= 0xA5,
+	COMMENT_OP		= 0xA9,
+	BREAKPIONT_OP		= 0xCC,
+	ONES_OP			= 0xFF,
+};
+
+#define FIELDLIST_OFFSET(_bits)		{ .type = OFFSET, \
+					  .name = "", \
+					  .bits = _bits * 8, \
+					}
+#define FIELDLIST_NAMESTR(_name, _bits)		{ .type = NAME_STRING, \
+					  .name = _name, \
+					  .bits = _bits, \
+					}
+
+#define FIELD_ANYACC			0
+#define FIELD_BYTEACC			1
+#define FIELD_WORDACC			2
+#define FIELD_DWORDACC			3
+#define FIELD_QWORDACC			4
+#define FIELD_BUFFERACC			5
+#define FIELD_NOLOCK			(0 << 4)
+#define FIELD_LOCK			(1 << 4)
+#define FIELD_PRESERVE			(0 << 5)
+#define FIELD_WRITEASONES		(1 << 5)
+#define FIELD_WRITEASZEROS		(2 << 5)
+
+enum field_type {
+	OFFSET,
+	NAME_STRING,
+	FIELD_TYPE_MAX,
+};
+
+struct fieldlist {
+	enum field_type type;
+	const char *name;
+	u32 bits;
+};
+
+#define OPREGION(rname, space, offset, len)	{.name = rname, \
+						 .regionspace = space, \
+						 .regionoffset = offset, \
+						 .regionlen = len, \
+						}
+
+enum region_space {
+	SYSTEMMEMORY,
+	SYSTEMIO,
+	PCI_CONFIG,
+	EMBEDDEDCONTROL,
+	SMBUS,
+	CMOS,
+	PCIBARTARGET,
+	IPMI,
+	GPIO_REGION,
+	GPSERIALBUS,
+	PCC,
+	FIXED_HARDWARE = 0x7F,
+	REGION_SPACE_MAX,
+};
+
+struct opregion {
+	const char *name;
+	enum region_space regionspace;
+	unsigned long regionoffset;
+	unsigned long regionlen;
+};
+
+#define DSM_UUID(DSM_UUID, DSM_CALLBACKS, DSM_COUNT, DSM_ARG) \
+	{ .uuid = DSM_UUID, \
+	.callbacks = DSM_CALLBACKS, \
+	.count = DSM_COUNT, \
+	.arg = DSM_ARG, \
+	}
+
+typedef void (*hid_callback_func)(struct acpi_ctx *ctx, void *arg);
+
+struct dsm_uuid {
+	const char *uuid;
+	hid_callback_func *callbacks;
+	size_t count;
+	void *arg;
+};
+
+/* version 1 has 15 fields, version 2 has 19, and version 3 has 21 */
+enum cppc_fields {
+	CPPC_HIGHEST_PERF, /* can be DWORD */
+	CPPC_NOMINAL_PERF, /* can be DWORD */
+	CPPC_LOWEST_NONL_PERF, /* can be DWORD */
+	CPPC_LOWEST_PERF, /* can be DWORD */
+	CPPC_GUARANTEED_PERF,
+	CPPC_DESIRED_PERF,
+	CPPC_MIN_PERF,
+	CPPC_MAX_PERF,
+	CPPC_PERF_REDUCE_TOLERANCE,
+	CPPC_TIME_WINDOW,
+	CPPC_COUNTER_WRAP, /* can be DWORD */
+	CPPC_REF_PERF_COUNTER,
+	CPPC_DELIVERED_PERF_COUNTER,
+	CPPC_PERF_LIMITED,
+	CPPC_ENABLE, /* can be System I/O */
+	CPPC_MAX_FIELDS_VER_1,
+	CPPC_AUTO_SELECT = /* can be DWORD */
+		CPPC_MAX_FIELDS_VER_1,
+	CPPC_AUTO_ACTIVITY_WINDOW,
+	CPPC_PERF_PREF,
+	CPPC_REF_PERF, /* can be DWORD */
+	CPPC_MAX_FIELDS_VER_2,
+	CPPC_LOWEST_FREQ = /* can be DWORD */
+		CPPC_MAX_FIELDS_VER_2,
+	CPPC_NOMINAL_FREQ, /* can be DWORD */
+	CPPC_MAX_FIELDS_VER_3,
+};
+
+struct cppc_config {
+	u32 version; /* must be 1, 2, or 3 */
+	/*
+	 * The generic struct acpi_gen_regaddr structure is being used, though
+	 * anything besides PPC or FFIXED generally requires checking
+	 * if the OS has advertised support for it (via _OSC).
+	 *
+	 * NOTE: some fields permit DWORDs to be used.  If you
+	 * provide a System Memory register with all zeros (which
+	 * represents unsupported) then this will be used as-is.
+	 * Otherwise, a System Memory register with a 32-bit
+	 * width will be converted into a DWORD field (the value
+	 * of which will be the value of 'addrl'.  Any other use
+	 * of System Memory register is currently undefined.
+	 * (i.e., if you have an actual need for System Memory
+	 * then you'll need to adjust this kludge).
+	 */
+	struct acpi_gen_regaddr regs[CPPC_MAX_FIELDS_VER_3];
+};
+
+void acpigen_write_return_integer(struct acpi_ctx *ctx, u64 arg);
+void acpigen_write_return_string(struct acpi_ctx *ctx, const char *arg);
+void acpigen_write_len_f(struct acpi_ctx *ctx);
+void acpigen_pop_len(struct acpi_ctx *ctx);
+void acpigen_set_current(struct acpi_ctx *ctx, char *curr);
+char *acpigen_get_current(struct acpi_ctx *ctx);
+char *acpigen_write_package(struct acpi_ctx *ctx, int nr_el);
+void acpigen_write_zero(struct acpi_ctx *ctx);
+void acpigen_write_one(struct acpi_ctx *ctx);
+void acpigen_write_ones(struct acpi_ctx *ctx);
+void acpigen_write_byte(struct acpi_ctx *ctx, unsigned int data);
+void acpigen_emit_byte(struct acpi_ctx *ctx, unsigned char data);
+void acpigen_emit_ext_op(struct acpi_ctx *ctx, u8 op);
+void acpigen_emit_word(struct acpi_ctx *ctx, unsigned int data);
+void acpigen_emit_dword(struct acpi_ctx *ctx, unsigned int data);
+void acpigen_emit_stream(struct acpi_ctx *ctx, const char *data, int size);
+void acpigen_emit_string(struct acpi_ctx *ctx, const char *string);
+void acpigen_emit_namestring(struct acpi_ctx *ctx, const char *namepath);
+void acpigen_emit_eisaid(struct acpi_ctx *ctx, const char *eisaid);
+void acpigen_write_word(struct acpi_ctx *ctx, unsigned int data);
+void acpigen_write_dword(struct acpi_ctx *ctx, unsigned int data);
+void acpigen_write_qword(struct acpi_ctx *ctx, u64 data);
+void acpigen_write_integer(struct acpi_ctx *ctx, u64 data);
+void acpigen_write_string(struct acpi_ctx *ctx, const char *string);
+void acpigen_write_coreboot_hid(struct acpi_ctx *ctx,
+				enum coreboot_acpi_ids id);
+void acpigen_write_name(struct acpi_ctx *ctx, const char *name);
+void acpigen_write_name_zero(struct acpi_ctx *ctx, const char *name);
+void acpigen_write_name_one(struct acpi_ctx *ctx, const char *name);
+void acpigen_write_name_string(struct acpi_ctx *ctx, const char *name,
+			       const char *string);
+void acpigen_write_name_dword(struct acpi_ctx *ctx, const char *name, u32 val);
+void acpigen_write_name_qword(struct acpi_ctx *ctx, const char *name, u64 val);
+void acpigen_write_name_byte(struct acpi_ctx *ctx, const char *name, u8 val);
+void acpigen_write_name_integer(struct acpi_ctx *ctx, const char *name,
+				u64 val);
+void acpigen_write_scope(struct acpi_ctx *ctx, const char *name);
+void acpigen_write_method(struct acpi_ctx *ctx, const char *name, int nargs);
+void acpigen_write_method_serialized(struct acpi_ctx *ctx, const char *name,
+				     int nargs);
+void acpigen_write_device(struct acpi_ctx *ctx, const char *name);
+void acpigen_write_ppc(struct acpi_ctx *ctx, u8 nr);
+void acpigen_write_ppc_nvs(struct acpi_ctx *ctx);
+void acpigen_write_empty_pct(struct acpi_ctx *ctx);
+void acpigen_write_empty_ptc(struct acpi_ctx *ctx);
+void acpigen_write_prw(struct acpi_ctx *ctx, u32 wake, u32 level);
+void acpigen_write_sta(struct acpi_ctx *ctx, u8 status);
+void acpigen_write_tpc(struct acpi_ctx *ctx, const char *gnvs_tpc_limit);
+void acpigen_write_pss_package(struct acpi_ctx *ctx, u32 corefreq, u32 power,
+			       u32 translat,
+			u32 busmlat, u32 control, u32 status);
+enum psd_coord {
+	SW_ALL = 0xfc,
+	SW_ANY = 0xfd,
+	HW_ALL = 0xfe
+};
+
+void acpigen_write_psd_package(struct acpi_ctx *ctx, u32 domain, u32 numprocs,
+			       enum psd_coord coordtype);
+void acpigen_write_cst_package_entry(struct acpi_ctx *ctx,
+				     struct acpi_cstate *cstate);
+void acpigen_write_cst_package(struct acpi_ctx *ctx, struct acpi_cstate *entry,
+			       int nentries);
+
+enum csd_coord {
+	CSD_HW_ALL = 0xfe,
+};
+
+void acpigen_write_CSD_package(struct acpi_ctx *ctx, u32 domain, u32 numprocs,
+			       enum csd_coord coordtype, u32 index);
+void acpigen_write_processor(struct acpi_ctx *ctx, u8 cpuindex, u32 pblock_addr,
+			     u8 pblock_len);
+void acpigen_write_processor_package(struct acpi_ctx *ctx, const char *name,
+				     uint first_core, uint core_count);
+void acpigen_write_processor_cnot(struct acpi_ctx *ctx, const uint num_cores);
+void acpigen_write_tss_package(struct acpi_ctx *ctx, int entries,
+			       struct acpi_tstate *tstate_list);
+void acpigen_write_tsd_package(struct acpi_ctx *ctx, u32 domain, u32 numprocs,
+			       enum psd_coord coordtype);
+void acpigen_write_mem32fixed(struct acpi_ctx *ctx, int readwrite, u32 base,
+			      u32 size);
+void acpigen_write_register_resource(struct acpi_ctx *ctx,
+				     const struct acpi_gen_regaddr *addr);
+void acpigen_write_irq(struct acpi_ctx *ctx, u16 mask);
+void acpigen_write_resourcetemplate_header(struct acpi_ctx *ctx);
+void acpigen_write_resourcetemplate_footer(struct acpi_ctx *ctx);
+int acpigen_write_uuid(struct acpi_ctx *ctx, const char *uuid);
+void acpigen_write_power_res(struct acpi_ctx *ctx, const char *name, u8 level,
+			     u16 order, const char *const dev_states[],
+			     size_t dev_states_count);
+void acpigen_write_sleep(struct acpi_ctx *ctx, u64 sleep_ms);
+void acpigen_write_store(struct acpi_ctx *ctx);
+void acpigen_write_store_ops(struct acpi_ctx *ctx, u8 src, u8 dst);
+void acpigen_write_or(struct acpi_ctx *ctx, u8 arg1, u8 arg2, u8 res);
+void acpigen_write_and(struct acpi_ctx *ctx, u8 arg1, u8 arg2, u8 res);
+void acpigen_write_not(struct acpi_ctx *ctx, u8 arg, u8 res);
+void acpigen_write_debug_string(struct acpi_ctx *ctx, const char *str);
+void acpigen_write_debug_integer(struct acpi_ctx *ctx, u64 val);
+void acpigen_write_debug_op(struct acpi_ctx *ctx, u8 op);
+void acpigen_write_if(struct acpi_ctx *ctx);
+void acpigen_write_if_and(struct acpi_ctx *ctx, u8 arg1, u8 arg2);
+void acpigen_write_if_lequal_op_int(struct acpi_ctx *ctx, u8 op, u64 val);
+void acpigen_write_else(struct acpi_ctx *ctx);
+void acpigen_write_to_buffer(struct acpi_ctx *ctx, u8 src, u8 dst);
+void acpigen_write_to_integer(struct acpi_ctx *ctx, u8 src, u8 dst);
+void acpigen_write_byte_buffer(struct acpi_ctx *ctx, u8 *arr, size_t size);
+void acpigen_write_return_byte_buffer(struct acpi_ctx *ctx, u8 *arr,
+				      size_t size);
+void acpigen_write_return_singleton_buffer(struct acpi_ctx *ctx, u8 arg);
+void acpigen_write_return_byte(struct acpi_ctx *ctx, u8 arg);
+void acpigen_write_upc(struct acpi_ctx *ctx, enum acpi_upc_type type);
+
+/*
+ * Generate ACPI AML code for _DSM method.
+ * This function takes as input uuid for the device, set of callbacks and
+ * argument to pass into the callbacks. Callbacks should ensure that Local0 and
+ * Local1 are left untouched. Use of Local2-Local7 is permitted in callbacks.
+ */
+int acpigen_write_dsm(struct acpi_ctx *ctx, const char *uuid,
+		      hid_callback_func callbacks[], size_t count, void *arg);
+int acpigen_write_dsm_uuid_arr(struct acpi_ctx *ctx, struct dsm_uuid *ids,
+			       size_t count);
+
+/*
+ * Generate ACPI AML code for _CPC (struct acpi_ctx *ctx, Continuous Perfmance
+ * Control). Execute the package function once to create a global table, then
+ * execute the method function within each processor object to
+ * create a method that points to the global table.
+ */
+int acpigen_write_cppc_package(struct acpi_ctx *ctx,
+			       const struct cppc_config *config);
+void acpigen_write_cppc_method(struct acpi_ctx *ctx);
+
+/*
+ * Generate ACPI AML code for _ROM method.
+ * This function takes as input ROM data and ROM length.
+ * The ROM length has to be multiple of 4096 and has to be less
+ * than the current implementation limit of 0x40000.
+ */
+int acpigen_write_rom(struct acpi_ctx *ctx, void *bios, const size_t length);
+/*
+ * Generate ACPI AML code for OperationRegion
+ * This function takes input region name, region space, region offset & region
+ * length.
+ */
+void acpigen_write_opregion(struct acpi_ctx *ctx, struct opregion *opreg);
+/*
+ * Generate ACPI AML code for Field
+ * This function takes input region name, fieldlist, count & flags.
+ */
+int acpigen_write_field(struct acpi_ctx *ctx, const char *name,
+			struct fieldlist *l, size_t count, uint flags);
+/*
+ * Generate ACPI AML code for IndexField
+ * This function takes input index name, data name, fieldlist, count & flags.
+ */
+int acpigen_write_indexfield(struct acpi_ctx *ctx, const char *idx,
+			     const char *data, struct fieldlist *l,
+			     size_t count, uint flags);
+
+/*
+ * Soc-implemented functions for generating ACPI AML code for GPIO handling. All
+ * these functions are expected to use only Local5, Local6 and Local7
+ * variables. If the functions call into another ACPI method, then there is no
+ * restriction on the use of Local variables. In case of get/read functions,
+ * return value is expected to be stored in Local0 variable.
+ *
+ * All functions return 0 on success and -1 on error.
+ */
+
+/* Generate ACPI AML code to return Rx value of GPIO in Local0. */
+int acpigen_soc_read_rx_gpio(struct acpi_ctx *ctx, uint gpio_num);
+
+/* Generate ACPI AML code to return Tx value of GPIO in Local0. */
+int acpigen_soc_get_tx_gpio(struct acpi_ctx *ctx, uint gpio_num);
+
+/* Generate ACPI AML code to set Tx value of GPIO to 1. */
+int acpigen_soc_set_tx_gpio(struct acpi_ctx *ctx, uint gpio_num);
+
+/* Generate ACPI AML code to set Tx value of GPIO to 0. */
+int acpigen_soc_clear_tx_gpio(struct acpi_ctx *ctx, uint gpio_num);
+
+/*
+ * Helper functions for enabling/disabling Tx GPIOs based on the GPIO
+ * polarity. These functions end up calling acpigen_soc_{set,clear}_tx_gpio to
+ * make callbacks into SoC acpigen code.
+ *
+ * Returns 0 on success and -1 on error.
+ */
+int acpigen_enable_tx_gpio(struct acpi_ctx *ctx, struct acpi_gpio *gpio);
+int acpigen_disable_tx_gpio(struct acpi_ctx *ctx, struct acpi_gpio *gpio);
+
+#endif
diff --git a/include/dm/acpi.h b/include/dm/acpi.h
index f3e9d73b78..0f78a506da 100644
--- a/include/dm/acpi.h
+++ b/include/dm/acpi.h
@@ -22,6 +22,9 @@ 
 /* Length of an ACPI name string including nul terminator */
 #define ACPI_NAME_MAX	5
 
+/* Number of nested objects supported */
+#define ACPIGEN_LENSTACK_SIZE 10
+
 #if !defined(__ACPI__)
 
 /**
@@ -34,12 +37,16 @@ 
  *	adding a new table. The RSDP holds pointers to the RSDP and XSDT.
  * @rsdt: Pointer to the Root System Description Table
  * @xsdt: Pointer to the Extended System Description Table
+ * @len_stack: Stack of 'length' words to fix up later
+ * @ltop: Points to current top of stack (0 = empty)
  */
 struct acpi_ctx {
 	void *current;
 	struct acpi_rsdp *rsdp;
 	struct acpi_rsdt *rsdt;
 	struct acpi_xsdt *xsdt;
+	char *len_stack[ACPIGEN_LENSTACK_SIZE];
+	int ltop;
 };
 
 /**
diff --git a/include/irq.h b/include/irq.h
index 632f48ff40..eeeef5b56c 100644
--- a/include/irq.h
+++ b/include/irq.h
@@ -8,6 +8,8 @@ 
 #ifndef __irq_H
 #define __irq_H
 
+struct ofnode_phandle_args;
+
 /*
  * Interupt controller types available. You can find a particular one with
  * irq_first_device_type()
diff --git a/include/log.h b/include/log.h
index 559ea7e933..90fdb6bf2d 100644
--- a/include/log.h
+++ b/include/log.h
@@ -50,6 +50,8 @@  enum log_category_t {
 	LOGC_SANDBOX,	/* Related to the sandbox board */
 	LOGC_BLOBLIST,	/* Bloblist */
 	LOGC_DEVRES,	/* Device resources (devres_... functions) */
+	/* Intel Advanced Configuration and Power Interface (ACPI) */
+	LOGC_ACPI,
 
 	LOGC_COUNT,	/* Number of log categories */
 	LOGC_END,	/* Sentinel value for a list of log categories */
diff --git a/lib/acpi/Makefile b/lib/acpi/Makefile
index 660491ef71..85a1f774ad 100644
--- a/lib/acpi/Makefile
+++ b/lib/acpi/Makefile
@@ -1,4 +1,6 @@ 
 # SPDX-License-Identifier: GPL-2.0+
 #
 
+obj-y += acpigen.o
+obj-y += acpi_device.o
 obj-y += acpi_table.o
diff --git a/lib/acpi/acpigen.c b/lib/acpi/acpigen.c
new file mode 100644
index 0000000000..4e7d1ce51e
--- /dev/null
+++ b/lib/acpi/acpigen.c
@@ -0,0 +1,1683 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generation of ACPI (Advanced Configuration and Power Interface) tables
+ *
+ * Copyright 2019 Google LLC
+ * Mostly taken from coreboot
+ */
+
+#define LOG_CATEGORY LOGC_ACPI
+
+#include <common.h>
+#include <dm.h>
+#include <hexdump.h>
+#include <uuid.h>
+#include <acpigen.h>
+#include <acpi_device.h>
+#include <acpi_table.h>
+#include <dm/acpi.h>
+#include <linux/ioport.h>
+
+/*
+ * Maximum length for an ACPI object generated by this code,
+ *
+ * If you need to change this, change acpigen_write_len_f(ctx) and
+ * acpigen_pop_len(ctx)
+ */
+#define ACPIGEN_MAXLEN 0xfffff
+
+/* CPU path format */
+#define ACPI_CPU_STRING "\\_PR.CP%02d"
+
+void acpigen_write_len_f(struct acpi_ctx *ctx)
+{
+	assert(ctx->ltop < (ACPIGEN_LENSTACK_SIZE - 1));
+	ctx->len_stack[ctx->ltop++] = ctx->current;
+	acpigen_emit_byte(ctx, 0);
+	acpigen_emit_byte(ctx, 0);
+	acpigen_emit_byte(ctx, 0);
+}
+
+void acpigen_pop_len(struct acpi_ctx *ctx)
+{
+	int len;
+	char *p;
+
+	assert(ctx->ltop > 0);
+	p = ctx->len_stack[--ctx->ltop];
+	len = ctx->current - (void *)p;
+	assert(len <= ACPIGEN_MAXLEN);
+	/* generate store length for 0xfffff max */
+	p[0] = (0x80 | (len & 0xf));
+	p[1] = (len >> 4 & 0xff);
+	p[2] = (len >> 12 & 0xff);
+}
+
+void acpigen_set_current(struct acpi_ctx *ctx, char *curr)
+{
+	ctx->current = curr;
+}
+
+char *acpigen_get_current(struct acpi_ctx *ctx)
+{
+	return ctx->current;
+}
+
+void acpigen_emit_byte(struct acpi_ctx *ctx, unsigned char b)
+{
+	*(u8 *)ctx->current++ = b;
+}
+
+void acpigen_emit_ext_op(struct acpi_ctx *ctx, u8 op)
+{
+	acpigen_emit_byte(ctx, EXT_OP_PREFIX);
+	acpigen_emit_byte(ctx, op);
+}
+
+void acpigen_emit_word(struct acpi_ctx *ctx, unsigned int data)
+{
+	acpigen_emit_byte(ctx, data & 0xff);
+	acpigen_emit_byte(ctx, (data >> 8) & 0xff);
+}
+
+void acpigen_emit_dword(struct acpi_ctx *ctx, unsigned int data)
+{
+	acpigen_emit_byte(ctx, data & 0xff);
+	acpigen_emit_byte(ctx, (data >> 8) & 0xff);
+	acpigen_emit_byte(ctx, (data >> 16) & 0xff);
+	acpigen_emit_byte(ctx, (data >> 24) & 0xff);
+}
+
+char *acpigen_write_package(struct acpi_ctx *ctx, int nr_el)
+{
+	char *p;
+
+	acpigen_emit_byte(ctx, PACKAGE_OP);
+	acpigen_write_len_f(ctx);
+	p = ctx->current;
+	acpigen_emit_byte(ctx, nr_el);
+
+	return p;
+}
+
+void acpigen_write_byte(struct acpi_ctx *ctx, unsigned int data)
+{
+	acpigen_emit_byte(ctx, BYTE_PREFIX);
+	acpigen_emit_byte(ctx, data & 0xff);
+}
+
+void acpigen_write_word(struct acpi_ctx *ctx, unsigned int data)
+{
+	acpigen_emit_byte(ctx, WORD_PREFIX);
+	acpigen_emit_word(ctx, data);
+}
+
+void acpigen_write_dword(struct acpi_ctx *ctx, unsigned int data)
+{
+	acpigen_emit_byte(ctx, DWORD_PREFIX);
+	acpigen_emit_dword(ctx, data);
+}
+
+void acpigen_write_qword(struct acpi_ctx *ctx, u64 data)
+{
+	acpigen_emit_byte(ctx, QWORD_PREFIX);
+	acpigen_emit_dword(ctx, data & 0xffffffff);
+	acpigen_emit_dword(ctx, (data >> 32) & 0xffffffff);
+}
+
+void acpigen_write_zero(struct acpi_ctx *ctx)
+{
+	acpigen_emit_byte(ctx, ZERO_OP);
+}
+
+void acpigen_write_one(struct acpi_ctx *ctx)
+{
+	acpigen_emit_byte(ctx, ONE_OP);
+}
+
+void acpigen_write_ones(struct acpi_ctx *ctx)
+{
+	acpigen_emit_byte(ctx, ONES_OP);
+}
+
+void acpigen_write_integer(struct acpi_ctx *ctx, u64 data)
+{
+	if (data == 0)
+		acpigen_write_zero(ctx);
+	else if (data == 1)
+		acpigen_write_one(ctx);
+	else if (data <= 0xff)
+		acpigen_write_byte(ctx, (unsigned char)data);
+	else if (data <= 0xffff)
+		acpigen_write_word(ctx, (unsigned int)data);
+	else if (data <= 0xffffffff)
+		acpigen_write_dword(ctx, (unsigned int)data);
+	else
+		acpigen_write_qword(ctx, data);
+}
+
+void acpigen_write_name_zero(struct acpi_ctx *ctx, const char *name)
+{
+	acpigen_write_name(ctx, name);
+	acpigen_write_one(ctx);
+}
+
+void acpigen_write_name_one(struct acpi_ctx *ctx, const char *name)
+{
+	acpigen_write_name(ctx, name);
+	acpigen_write_zero(ctx);
+}
+
+void acpigen_write_name_byte(struct acpi_ctx *ctx, const char *name, u8 val)
+{
+	acpigen_write_name(ctx, name);
+	acpigen_write_byte(ctx, val);
+}
+
+void acpigen_write_name_dword(struct acpi_ctx *ctx, const char *name, u32 val)
+{
+	acpigen_write_name(ctx, name);
+	acpigen_write_dword(ctx, val);
+}
+
+void acpigen_write_name_qword(struct acpi_ctx *ctx, const char *name, u64 val)
+{
+	acpigen_write_name(ctx, name);
+	acpigen_write_qword(ctx, val);
+}
+
+void acpigen_write_name_integer(struct acpi_ctx *ctx, const char *name, u64 val)
+{
+	acpigen_write_name(ctx, name);
+	acpigen_write_integer(ctx, val);
+}
+
+void acpigen_write_name_string(struct acpi_ctx *ctx, const char *name,
+			       const char *string)
+{
+	acpigen_write_name(ctx, name);
+	acpigen_write_string(ctx, string);
+}
+
+void acpigen_emit_stream(struct acpi_ctx *ctx, const char *data, int size)
+{
+	int i;
+
+	for (i = 0; i < size; i++)
+		acpigen_emit_byte(ctx, data[i]);
+}
+
+void acpigen_emit_string(struct acpi_ctx *ctx, const char *string)
+{
+	acpigen_emit_stream(ctx, string, string ? strlen(string) : 0);
+	acpigen_emit_byte(ctx, '\0'); /* NUL */
+}
+
+void acpigen_write_string(struct acpi_ctx *ctx, const char *string)
+{
+	acpigen_emit_byte(ctx, STRING_PREFIX);
+	acpigen_emit_string(ctx, string);
+}
+
+void acpigen_write_coreboot_hid(struct acpi_ctx *ctx, enum coreboot_acpi_ids id)
+{
+	char hid[9]; /* BOOTxxxx */
+
+	snprintf(hid, sizeof(hid), "%.4s%04X", COREBOOT_ACPI_ID, id);
+	acpigen_write_name_string(ctx, "_HID", hid);
+}
+
+/*
+ * The naming conventions for ACPI namespace names are a bit tricky as
+ * each element has to be 4 chars wide ("All names are a fixed 32 bits.")
+ * and "By convention, when an ASL compiler pads a name shorter than 4
+ * characters, it is done so with trailing underscores ('_')".
+ *
+ * Check sections 5.3, 18.2.2 and 18.4 of ACPI spec 3.0 for details.
+ */
+
+static void acpigen_emit_simple_namestring(struct acpi_ctx *ctx,
+					   const char *name)
+{
+	char ud[] = "____";
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		if ((name[i] == '\0') || (name[i] == '.')) {
+			acpigen_emit_stream(ctx, ud, 4 - i);
+			break;
+		}
+		acpigen_emit_byte(ctx, name[i]);
+	}
+}
+
+static void acpigen_emit_double_namestring(struct acpi_ctx *ctx,
+					   const char *name, int dotpos)
+{
+	acpigen_emit_byte(ctx, DUAL_NAME_PREFIX);
+	acpigen_emit_simple_namestring(ctx, name);
+	acpigen_emit_simple_namestring(ctx, &name[dotpos + 1]);
+}
+
+static void acpigen_emit_multi_namestring(struct acpi_ctx *ctx,
+					  const char *name)
+{
+	int count = 0;
+	unsigned char *pathlen;
+
+	acpigen_emit_byte(ctx, MULTI_NAME_PREFIX);
+	acpigen_emit_byte(ctx, ZERO_OP);
+	pathlen = ((unsigned char *)ctx->current) - 1;
+
+	while (name[0] != '\0') {
+		acpigen_emit_simple_namestring(ctx, name);
+		/* find end or next entity */
+		while ((name[0] != '.') && (name[0] != '\0'))
+			name++;
+		/* forward to next */
+		if (name[0] == '.')
+			name++;
+		count++;
+	}
+
+	pathlen[0] = count;
+}
+
+void acpigen_emit_namestring(struct acpi_ctx *ctx, const char *namepath)
+{
+	int dotcount = 0, i;
+	int dotpos = 0;
+
+	/* We can start with a '\'. */
+	if (namepath[0] == '\\') {
+		acpigen_emit_byte(ctx, '\\');
+		namepath++;
+	}
+
+	/* And there can be any number of '^' */
+	while (namepath[0] == '^') {
+		acpigen_emit_byte(ctx, '^');
+		namepath++;
+	}
+
+	/*
+	 * If we have only \\ or only ^...^ then we need to add a null name
+	 * (0x00)
+	 */
+	if (namepath[0] == '\0') {
+		acpigen_emit_byte(ctx, ZERO_OP);
+		return;
+	}
+
+	i = 0;
+	while (namepath[i] != '\0') {
+		if (namepath[i] == '.') {
+			dotcount++;
+			dotpos = i;
+		}
+		i++;
+	}
+
+	if (dotcount == 0)
+		acpigen_emit_simple_namestring(ctx, namepath);
+	else if (dotcount == 1)
+		acpigen_emit_double_namestring(ctx, namepath, dotpos);
+	else
+		acpigen_emit_multi_namestring(ctx, namepath);
+}
+
+void acpigen_write_name(struct acpi_ctx *ctx, const char *name)
+{
+	acpigen_emit_byte(ctx, NAME_OP);
+	acpigen_emit_namestring(ctx, name);
+}
+
+void acpigen_write_scope(struct acpi_ctx *ctx, const char *name)
+{
+	acpigen_emit_byte(ctx, SCOPE_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_emit_namestring(ctx, name);
+}
+
+void acpigen_write_processor(struct acpi_ctx *ctx, u8 cpuindex, u32 pblock_addr,
+			     u8 pblock_len)
+{
+	/*
+	 * Processor (\_PR.CPcpuindex, cpuindex, pblock_addr, pblock_len)
+	 * {
+	 */
+	char pscope[16];
+
+	acpigen_emit_ext_op(ctx, PROCESSOR_OP);
+	acpigen_write_len_f(ctx);
+
+	snprintf(pscope, sizeof(pscope), ACPI_CPU_STRING, (uint)cpuindex);
+	acpigen_emit_namestring(ctx, pscope);
+	acpigen_emit_byte(ctx, cpuindex);
+	acpigen_emit_dword(ctx, pblock_addr);
+	acpigen_emit_byte(ctx, pblock_len);
+}
+
+void acpigen_write_processor_package(struct acpi_ctx *ctx,
+				     const char *const name,
+				     const uint first_core,
+				     const uint core_count)
+{
+	uint i;
+	char pscope[16];
+
+	acpigen_write_name(ctx, name);
+	acpigen_write_package(ctx, core_count);
+	for (i = first_core; i < first_core + core_count; ++i) {
+		snprintf(pscope, sizeof(pscope), ACPI_CPU_STRING, i);
+		acpigen_emit_namestring(ctx, pscope);
+	}
+	acpigen_pop_len(ctx);
+}
+
+/* Method to notify all CPU cores */
+void acpigen_write_processor_cnot(struct acpi_ctx *ctx, const uint num_cores)
+{
+	int core_id;
+
+	acpigen_write_method(ctx, "\\_PR.CNOT", 1);
+	for (core_id = 0; core_id < num_cores; core_id++) {
+		char buffer[30];
+
+		snprintf(buffer, sizeof(buffer), ACPI_CPU_STRING, core_id);
+		acpigen_emit_byte(ctx, NOTIFY_OP);
+		acpigen_emit_namestring(ctx, buffer);
+		acpigen_emit_byte(ctx, ARG0_OP);
+	}
+	acpigen_pop_len(ctx);
+}
+
+/*
+ * Generate ACPI AML code for OperationRegion
+ * Arg0: Pointer to struct opregion opreg = OPREGION(rname, space, offset, len)
+ * where rname is region name, space is region space, offset is region offset &
+ * len is region length.
+ * OperationRegion(regionname, regionspace, regionoffset, regionlength)
+ */
+void acpigen_write_opregion(struct acpi_ctx *ctx, struct opregion *opreg)
+{
+	/* OpregionOp */
+	acpigen_emit_ext_op(ctx, OPREGION_OP);
+	/* NameString 4 chars only */
+	acpigen_emit_simple_namestring(ctx, opreg->name);
+	/* RegionSpace */
+	acpigen_emit_byte(ctx, opreg->regionspace);
+	/* RegionOffset & RegionLen, it can be byte word or double word */
+	acpigen_write_integer(ctx, opreg->regionoffset);
+	acpigen_write_integer(ctx, opreg->regionlen);
+}
+
+static void acpigen_write_field_length(struct acpi_ctx *ctx, u32 len)
+{
+	u8 i, j;
+	u8 emit[4];
+
+	i = 1;
+	if (len < 0x40) {
+		emit[0] = len & 0x3F;
+	} else {
+		emit[0] = len & 0xF;
+		len >>= 4;
+		while (len) {
+			emit[i] = len & 0xFF;
+			i++;
+			len >>= 8;
+		}
+	}
+	/* Update bit 7:6 : Number of bytes followed by emit[0] */
+	emit[0] |= (i - 1) << 6;
+
+	for (j = 0; j < i; j++)
+		acpigen_emit_byte(ctx, emit[j]);
+}
+
+static int acpigen_write_field_offset(struct acpi_ctx *ctx, u32 offset,
+				      u32 current_bit_pos)
+{
+	u32 diff_bits;
+
+	if (offset < current_bit_pos) {
+		log_warning("Cannot move offset backward");
+		return -ESPIPE;
+	}
+
+	diff_bits = offset - current_bit_pos;
+	/* Upper limit */
+	if (diff_bits > 0xFFFFFFF) {
+		log_warning("Offset very large to encode");
+		return E2BIG;
+	}
+
+	acpigen_emit_byte(ctx, 0);
+	acpigen_write_field_length(ctx, diff_bits);
+
+	return 0;
+}
+
+static void acpigen_write_field_name(struct acpi_ctx *ctx, const char *name,
+				     u32 size)
+{
+	acpigen_emit_simple_namestring(ctx, name);
+	acpigen_write_field_length(ctx, size);
+}
+
+/*
+ * Generate ACPI AML code for Field
+ * Arg0: region name
+ * Arg1: Pointer to struct fieldlist.
+ * Arg2: no. of entries in Arg1
+ * Arg3: flags which indicate filed access type, lock rule  & update rule.
+ * Example with fieldlist
+ * struct fieldlist l[] = {
+ *	FIELDLIST_OFFSET(0x84),
+ *	FIELDLIST_NAMESTR("PMCS", 2),
+ *	};
+ * acpigen_write_field("UART", l, ARRAY_SIZE(l), FIELD_ANYACC | FIELD_NOLOCK |
+ *								FIELD_PRESERVE);
+ * Output:
+ * Field (UART, AnyAcc, NoLock, Preserve)
+ *	{
+ *		Offset (0x84),
+ *		PMCS,   2
+ *	}
+ */
+int acpigen_write_field(struct acpi_ctx *ctx, const char *name,
+			struct fieldlist *l, size_t count, uint flags)
+{
+	int i;
+	u32 current_bit_pos = 0;
+	int ret;
+
+	/* FieldOp */
+	acpigen_emit_ext_op(ctx, FIELD_OP);
+	/* Package Length */
+	acpigen_write_len_f(ctx);
+	/* NameString 4 chars only */
+	acpigen_emit_simple_namestring(ctx, name);
+	/* Field Flag */
+	acpigen_emit_byte(ctx, flags);
+
+	for (i = 0; i < count; i++) {
+		switch (l[i].type) {
+		case NAME_STRING:
+			acpigen_write_field_name(ctx, l[i].name, l[i].bits);
+			current_bit_pos += l[i].bits;
+			break;
+		case OFFSET:
+			ret = acpigen_write_field_offset(ctx, l[i].bits,
+							 current_bit_pos);
+			if (ret)
+				return log_msg_ret("field", ret);
+			current_bit_pos = l[i].bits;
+			break;
+		default:
+			log_err("Invalid field type %#x\n", l[i].type);
+			return -EDOM;
+		}
+	}
+	acpigen_pop_len(ctx);
+
+	return 0;
+}
+
+/*
+ * Generate ACPI AML code for IndexField
+ * Arg0: region name
+ * Arg1: Pointer to struct fieldlist.
+ * Arg2: no. of entries in Arg1
+ * Arg3: flags which indicate filed access type, lock rule  & update rule.
+ * Example with fieldlist
+ * struct fieldlist l[] = {
+ *	FIELDLIST_OFFSET(0x84),
+ *	FIELDLIST_NAMESTR("PMCS", 2),
+ *	};
+ * acpigen_write_field("IDX", "DATA" l, ARRAY_SIZE(l), FIELD_ANYACC |
+ *						       FIELD_NOLOCK |
+ *						       FIELD_PRESERVE);
+ * Output:
+ * IndexField (IDX, DATA, AnyAcc, NoLock, Preserve)
+ *	{
+ *		Offset (0x84),
+ *		PMCS,   2
+ *	}
+ */
+int acpigen_write_indexfield(struct acpi_ctx *ctx, const char *idx,
+			     const char *data, struct fieldlist *l,
+			     size_t count, uint flags)
+{
+	u16 i;
+	u32 current_bit_pos = 0;
+	int ret;
+
+	/* FieldOp */
+	acpigen_emit_ext_op(ctx, INDEX_FIELD_OP);
+	/* Package Length */
+	acpigen_write_len_f(ctx);
+	/* NameString 4 chars only */
+	acpigen_emit_simple_namestring(ctx, idx);
+	/* NameString 4 chars only */
+	acpigen_emit_simple_namestring(ctx, data);
+	/* Field Flag */
+	acpigen_emit_byte(ctx, flags);
+
+	for (i = 0; i < count; i++) {
+		switch (l[i].type) {
+		case NAME_STRING:
+			acpigen_write_field_name(ctx, l[i].name, l[i].bits);
+			current_bit_pos += l[i].bits;
+			break;
+		case OFFSET:
+			ret = acpigen_write_field_offset(ctx, l[i].bits,
+							 current_bit_pos);
+			if (ret)
+				return log_msg_ret("field", ret);
+			current_bit_pos = l[i].bits;
+			break;
+		default:
+			log_err("Invalid field type 0x%X\n", l[i].type);
+			return -EDOM;
+		}
+	}
+	acpigen_pop_len(ctx);
+
+	return 0;
+}
+
+void acpigen_write_empty_pct(struct acpi_ctx *ctx)
+{
+	/*
+	 * Name (_PCT, Package (0x02)
+	 * {
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	},
+	 *
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	}
+	 * })
+	 */
+	static char stream[] = {
+		/* 00000030    "0._PCT.," */
+		0x08, 0x5F, 0x50, 0x43, 0x54, 0x12, 0x2C,
+		/* 00000038    "........" */
+		0x02, 0x11, 0x14, 0x0A, 0x11, 0x82, 0x0C, 0x00,
+		/* 00000040    "........" */
+		0x7F, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		/* 00000048    "....y..." */
+		0x00, 0x00, 0x00, 0x00, 0x79, 0x00, 0x11, 0x14,
+		/* 00000050    "........" */
+		0x0A, 0x11, 0x82, 0x0C, 0x00, 0x7F, 0x00, 0x00,
+		/* 00000058    "........" */
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+		0x00, 0x79, 0x00
+	};
+	acpigen_emit_stream(ctx, stream, ARRAY_SIZE(stream));
+}
+
+void acpigen_write_empty_ptc(struct acpi_ctx *ctx)
+{
+	/*
+	 * Name (_PTC, Package (0x02)
+	 * {
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	},
+	 *
+	 *	ResourceTemplate ()
+	 *	{
+	 *		Register (FFixedHW,
+	 *			0x00,               // Bit Width
+	 *			0x00,               // Bit Offset
+	 *			0x0000000000000000, // Address
+	 *			,)
+	 *	}
+	 * })
+	 */
+	struct acpi_gen_regaddr addr = {
+		.space_id    = ACPI_ADDRESS_SPACE_FIXED,
+		.bit_width   = 0,
+		.bit_offset  = 0,
+		.access_size = 0,
+		.addrl       = 0,
+		.addrh       = 0,
+	};
+
+	acpigen_write_name(ctx, "_PTC");
+	acpigen_write_package(ctx, 2);
+
+	/* ControlRegister */
+	acpigen_write_register_resource(ctx, &addr);
+
+	/* StatusRegister */
+	acpigen_write_register_resource(ctx, &addr);
+
+	acpigen_pop_len(ctx);
+}
+
+static void __acpigen_write_method(struct acpi_ctx *ctx, const char *name,
+				   u8 flags)
+{
+	acpigen_emit_byte(ctx, METHOD_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_emit_namestring(ctx, name);
+	acpigen_emit_byte(ctx, flags);
+}
+
+/* Method (name, nargs, NotSerialized) */
+void acpigen_write_method(struct acpi_ctx *ctx, const char *name, int nargs)
+{
+	__acpigen_write_method(ctx, name, (nargs & 7));
+}
+
+/* Method (name, nargs, Serialized) */
+void acpigen_write_method_serialized(struct acpi_ctx *ctx, const char *name,
+				     int nargs)
+{
+	__acpigen_write_method(ctx, name, (nargs & 7) | (1 << 3));
+}
+
+void acpigen_write_device(struct acpi_ctx *ctx, const char *name)
+{
+	acpigen_emit_ext_op(ctx, DEVICE_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_emit_namestring(ctx, name);
+}
+
+void acpigen_write_sta(struct acpi_ctx *ctx, u8 status)
+{
+	/* Method (_STA, 0, NotSerialized) { Return (status) } */
+	acpigen_write_method(ctx, "_STA", 0);
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_write_byte(ctx, status);
+	acpigen_pop_len(ctx);
+}
+
+/*
+ * Generates a func with max supported P-states.
+ */
+void acpigen_write_ppc(struct acpi_ctx *ctx, u8 nr)
+{
+	/*
+	 * Method (_PPC, 0, NotSerialized)
+	 * {
+	 *	Return (nr)
+	 * }
+	 */
+	acpigen_write_method(ctx, "_PPC", 0);
+	acpigen_emit_byte(ctx, RETURN_OP);
+	/* arg */
+	acpigen_write_byte(ctx, nr);
+	acpigen_pop_len(ctx);
+}
+
+/*
+ * Generates a func with max supported P-states saved
+ * in the variable PPCM.
+ */
+void acpigen_write_ppc_nvs(struct acpi_ctx *ctx)
+{
+	/*
+	 * Method (_PPC, 0, NotSerialized)
+	 * {
+	 *	Return (PPCM)
+	 * }
+	 */
+	acpigen_write_method(ctx, "_PPC", 0);
+	acpigen_emit_byte(ctx, RETURN_OP);
+	/* arg */
+	acpigen_emit_namestring(ctx, "PPCM");
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_tpc(struct acpi_ctx *ctx, const char *gnvs_tpc_limit)
+{
+	/*
+	 * // Sample _TPC method
+	 * Method (_TPC, 0, NotSerialized)
+	 * {
+	 *	Return (\TLVL)
+	 * }
+	 */
+	acpigen_write_method(ctx, "_TPC", 0);
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_emit_namestring(ctx, gnvs_tpc_limit);
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_prw(struct acpi_ctx *ctx, u32 wake, u32 level)
+{
+	/*
+	 * Name (_PRW, Package () { wake, level }
+	 */
+	acpigen_write_name(ctx, "_PRW");
+	acpigen_write_package(ctx, 2);
+	acpigen_write_integer(ctx, wake);
+	acpigen_write_integer(ctx, level);
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_pss_package(struct acpi_ctx *ctx, u32 core_freq, u32 power,
+			       u32 trans_lat, u32 busm_lat, u32 control,
+			       u32 status)
+{
+	acpigen_write_package(ctx, 6);
+	acpigen_write_dword(ctx, core_freq);
+	acpigen_write_dword(ctx, power);
+	acpigen_write_dword(ctx, trans_lat);
+	acpigen_write_dword(ctx, busm_lat);
+	acpigen_write_dword(ctx, control);
+	acpigen_write_dword(ctx, status);
+	acpigen_pop_len(ctx);
+
+	log_debug("PSS: %uMHz power %u control 0x%x status 0x%x\n",
+		  core_freq, power, control, status);
+}
+
+void acpigen_write_psd_package(struct acpi_ctx *ctx, u32 domain, u32 numprocs,
+			       enum psd_coord coordtype)
+{
+	acpigen_write_name(ctx, "_PSD");
+	acpigen_write_package(ctx, 1);
+	acpigen_write_package(ctx, 5);
+	acpigen_write_byte(ctx, 5);	// 5 values
+	acpigen_write_byte(ctx, 0);	// revision 0
+	acpigen_write_dword(ctx, domain);
+	acpigen_write_dword(ctx, coordtype);
+	acpigen_write_dword(ctx, numprocs);
+	acpigen_pop_len(ctx);
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_cst_package_entry(struct acpi_ctx *ctx,
+				     struct acpi_cstate *cstate)
+{
+	acpigen_write_package(ctx, 4);
+	acpigen_write_register_resource(ctx, &cstate->resource);
+	acpigen_write_dword(ctx, cstate->ctype);
+	acpigen_write_dword(ctx, cstate->latency);
+	acpigen_write_dword(ctx, cstate->power);
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_cst_package(struct acpi_ctx *ctx, struct acpi_cstate *cstate,
+			       int nentries)
+{
+	int i;
+
+	acpigen_write_name(ctx, "_CST");
+	acpigen_write_package(ctx, nentries + 1);
+	acpigen_write_dword(ctx, nentries);
+
+	for (i = 0; i < nentries; i++)
+		acpigen_write_cst_package_entry(ctx, cstate + i);
+
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_csd_package(struct acpi_ctx *ctx, u32 domain, u32 numprocs,
+			       enum csd_coord coordtype, u32 index)
+{
+	acpigen_write_name(ctx, "_CSD");
+	acpigen_write_package(ctx, 1);
+	acpigen_write_package(ctx, 6);
+	acpigen_write_byte(ctx, 6);	// 6 values
+	acpigen_write_byte(ctx, 0);	// revision 0
+	acpigen_write_dword(ctx, domain);
+	acpigen_write_dword(ctx, coordtype);
+	acpigen_write_dword(ctx, numprocs);
+	acpigen_write_dword(ctx, index);
+	acpigen_pop_len(ctx);
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_tss_package(struct acpi_ctx *ctx, int entries,
+			       struct acpi_tstate *tstate_list)
+{
+	/*
+	 * Sample _TSS package with 100% and 50% duty cycles
+	 * Name (_TSS, Package (0x02)
+	 * {
+	 *	Package(){100, 1000, 0, 0x00, 0)
+	 *	Package(){50, 520, 0, 0x18, 0)
+	 * })
+	 */
+	int i;
+	struct acpi_tstate *tstate = tstate_list;
+
+	acpigen_write_name(ctx, "_TSS");
+	acpigen_write_package(ctx, entries);
+
+	for (i = 0; i < entries; i++) {
+		acpigen_write_package(ctx, 5);
+		acpigen_write_dword(ctx, tstate->percent);
+		acpigen_write_dword(ctx, tstate->power);
+		acpigen_write_dword(ctx, tstate->latency);
+		acpigen_write_dword(ctx, tstate->control);
+		acpigen_write_dword(ctx, tstate->status);
+		acpigen_pop_len(ctx);
+		tstate++;
+	}
+
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_tsd_package(struct acpi_ctx *ctx, u32 domain, u32 numprocs,
+			       enum psd_coord coordtype)
+{
+	acpigen_write_name(ctx, "_TSD");
+	acpigen_write_package(ctx, 1);
+	acpigen_write_package(ctx, 5);
+	acpigen_write_byte(ctx, 5);	// 5 values
+	acpigen_write_byte(ctx, 0);	// revision 0
+	acpigen_write_dword(ctx, domain);
+	acpigen_write_dword(ctx, coordtype);
+	acpigen_write_dword(ctx, numprocs);
+	acpigen_pop_len(ctx);
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_mem32fixed(struct acpi_ctx *ctx, int readwrite, u32 base,
+			      u32 size)
+{
+	/*
+	 * ACPI 4.0 section 6.4.3.4: 32-Bit Fixed Memory Range Descriptor
+	 * Byte 0:
+	 *   Bit7  : 1 => big item
+	 *   Bit6-0: 0000110 (0x6) => 32-bit fixed memory
+	 */
+	acpigen_emit_byte(ctx, 0x86);
+	/* Byte 1+2: length (0x0009) */
+	acpigen_emit_byte(ctx, 0x09);
+	acpigen_emit_byte(ctx, 0x00);
+	/* bit1-7 are ignored */
+	acpigen_emit_byte(ctx, readwrite ? 0x01 : 0x00);
+	acpigen_emit_dword(ctx, base);
+	acpigen_emit_dword(ctx, size);
+}
+
+static void acpigen_write_register(struct acpi_ctx *ctx,
+				   const struct acpi_gen_regaddr *addr)
+{
+	acpigen_emit_byte(ctx, 0x82);		/* Register Descriptor */
+	acpigen_emit_byte(ctx, 0x0c);		/* Register Length 7:0 */
+	acpigen_emit_byte(ctx, 0x00);		/* Register Length 15:8 */
+	acpigen_emit_byte(ctx, addr->space_id);
+	acpigen_emit_byte(ctx, addr->bit_width);
+	acpigen_emit_byte(ctx, addr->bit_offset);
+	acpigen_emit_byte(ctx, addr->access_size);
+	acpigen_emit_dword(ctx, addr->addrl);
+	acpigen_emit_dword(ctx, addr->addrh);
+}
+
+void acpigen_write_register_resource(struct acpi_ctx *ctx,
+				     const struct acpi_gen_regaddr *addr)
+{
+	acpigen_write_resourcetemplate_header(ctx);
+	acpigen_write_register(ctx, addr);
+	acpigen_write_resourcetemplate_footer(ctx);
+}
+
+void acpigen_write_irq(struct acpi_ctx *ctx, u16 mask)
+{
+	/*
+	 * ACPI 3.0b section 6.4.2.1: IRQ Descriptor
+	 * Byte 0:
+	 *   Bit7  : 0 => small item
+	 *   Bit6-3: 0100 (0x4) => IRQ port descriptor
+	 *   Bit2-0: 010 (0x2) => 2 Bytes long
+	 */
+	acpigen_emit_byte(ctx, 0x22);
+	acpigen_emit_byte(ctx, mask & 0xff);
+	acpigen_emit_byte(ctx, (mask >> 8) & 0xff);
+}
+
+void acpigen_write_resourcetemplate_header(struct acpi_ctx *ctx)
+{
+	/*
+	 * A ResourceTemplate() is a Buffer() with a
+	 * (Byte|Word|DWord) containing the length, followed by one or more
+	 * resource items, terminated by the end tag.
+	 * (small item 0xf, len 1)
+	 */
+	acpigen_emit_byte(ctx, BUFFER_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_emit_byte(ctx, WORD_PREFIX);
+	ctx->len_stack[ctx->ltop++] = ctx->current;
+	/*
+	 * Add two dummy bytes for the ACPI word (keep aligned with the
+	 * calclulation in acpigen_write_resourcetemplate() below)
+	 */
+	acpigen_emit_byte(ctx, 0x00);
+	acpigen_emit_byte(ctx, 0x00);
+}
+
+void acpigen_write_resourcetemplate_footer(struct acpi_ctx *ctx)
+{
+	char *p = ctx->len_stack[--ctx->ltop];
+	int len;
+	/*
+	 * end tag (acpi 4.0 Section 6.4.2.8)
+	 * 0x79 <checksum>
+	 * 0x00 is treated as a good checksum according to the spec
+	 * and is what iasl generates.
+	 */
+	acpigen_emit_byte(ctx, 0x79);
+	acpigen_emit_byte(ctx, 0x00);
+
+	/*
+	 * Start counting past the 2-bytes length added in
+	 * acpigen_write_resourcetemplate() above
+	 */
+	len = (char *)ctx->current - (p + 2);
+
+	/* patch len word */
+	p[0] = len & 0xff;
+	p[1] = (len >> 8) & 0xff;
+	/* patch len field */
+	acpigen_pop_len(ctx);
+}
+
+/*
+ * ToUUID(uuid)
+ *
+ * ACPI 6.1 Section 19.6.136 table 19-385 defines a special output
+ * order for the bytes that make up a UUID Buffer object.
+ * UUID byte order for input:
+ *   aabbccdd-eeff-gghh-iijj-kkllmmnnoopp
+ * UUID byte order for output:
+ *   ddccbbaa-ffee-hhgg-iijj-kkllmmnnoopp
+ */
+#define UUID_LEN 16
+int acpigen_write_uuid(struct acpi_ctx *ctx, const char *uuid)
+{
+	u8 buf[UUID_LEN];
+	size_t i, order[UUID_LEN] = { 3, 2, 1, 0, 5, 4, 7, 6,
+				      8, 9, 10, 11, 12, 13, 14, 15 };
+	int ret;
+
+	/* Parse UUID string into bytes */
+	ret = uuid_str_to_bin(uuid, buf, UUID_STR_FORMAT_STD);
+	if (ret)
+		return log_msg_ret("bad hex", -EINVAL);
+
+	/* BufferOp */
+	acpigen_emit_byte(ctx, BUFFER_OP);
+	acpigen_write_len_f(ctx);
+
+	/* Buffer length in bytes */
+	acpigen_write_word(ctx, UUID_LEN);
+
+	/* Output UUID in expected order */
+	for (i = 0; i < UUID_LEN; i++)
+		acpigen_emit_byte(ctx, buf[order[i]]);
+
+	acpigen_pop_len(ctx);
+
+	return 0;
+}
+
+/*
+ * Name (_PRx, Package(One) { name })
+ * ...
+ * PowerResource (name, level, order)
+ */
+void acpigen_write_power_res(struct acpi_ctx *ctx, const char *name, u8 level,
+			     u16 order, const char *const dev_states[],
+			     size_t dev_states_count)
+{
+	size_t i;
+
+	for (i = 0; i < dev_states_count; i++) {
+		acpigen_write_name(ctx, dev_states[i]);
+		acpigen_write_package(ctx, 1);
+		acpigen_emit_simple_namestring(ctx, name);
+		acpigen_pop_len(ctx);		/* Package */
+	}
+
+	acpigen_emit_ext_op(ctx, POWER_RES_OP);
+
+	acpigen_write_len_f(ctx);
+
+	acpigen_emit_simple_namestring(ctx, name);
+	acpigen_emit_byte(ctx, level);
+	acpigen_emit_word(ctx, order);
+}
+
+/* Sleep (ms) */
+void acpigen_write_sleep(struct acpi_ctx *ctx, u64 sleep_ms)
+{
+	acpigen_emit_ext_op(ctx, SLEEP_OP);
+	acpigen_write_integer(ctx, sleep_ms);
+}
+
+void acpigen_write_store(struct acpi_ctx *ctx)
+{
+	acpigen_emit_byte(ctx, STORE_OP);
+}
+
+/* Store (src, dst) */
+void acpigen_write_store_ops(struct acpi_ctx *ctx, u8 src, u8 dst)
+{
+	acpigen_write_store(ctx);
+	acpigen_emit_byte(ctx, src);
+	acpigen_emit_byte(ctx, dst);
+}
+
+/* Or (arg1, arg2, res) */
+void acpigen_write_or(struct acpi_ctx *ctx, u8 arg1, u8 arg2, u8 res)
+{
+	acpigen_emit_byte(ctx, OR_OP);
+	acpigen_emit_byte(ctx, arg1);
+	acpigen_emit_byte(ctx, arg2);
+	acpigen_emit_byte(ctx, res);
+}
+
+/* And (arg1, arg2, res) */
+void acpigen_write_and(struct acpi_ctx *ctx, u8 arg1, u8 arg2, u8 res)
+{
+	acpigen_emit_byte(ctx, AND_OP);
+	acpigen_emit_byte(ctx, arg1);
+	acpigen_emit_byte(ctx, arg2);
+	acpigen_emit_byte(ctx, res);
+}
+
+/* Not (arg, res) */
+void acpigen_write_not(struct acpi_ctx *ctx, u8 arg, u8 res)
+{
+	acpigen_emit_byte(ctx, NOT_OP);
+	acpigen_emit_byte(ctx, arg);
+	acpigen_emit_byte(ctx, res);
+}
+
+/* Store (str, DEBUG) */
+void acpigen_write_debug_string(struct acpi_ctx *ctx, const char *str)
+{
+	acpigen_write_store(ctx);
+	acpigen_write_string(ctx, str);
+	acpigen_emit_ext_op(ctx, DEBUG_OP);
+}
+
+/* Store (val, DEBUG) */
+void acpigen_write_debug_integer(struct acpi_ctx *ctx, u64 val)
+{
+	acpigen_write_store(ctx);
+	acpigen_write_integer(ctx, val);
+	acpigen_emit_ext_op(ctx, DEBUG_OP);
+}
+
+/* Store (op, DEBUG) */
+void acpigen_write_debug_op(struct acpi_ctx *ctx, u8 op)
+{
+	acpigen_write_store(ctx);
+	acpigen_emit_byte(ctx, op);
+	acpigen_emit_ext_op(ctx, DEBUG_OP);
+}
+
+void acpigen_write_if(struct acpi_ctx *ctx)
+{
+	acpigen_emit_byte(ctx, IF_OP);
+	acpigen_write_len_f(ctx);
+}
+
+/* If (And (arg1, arg2)) */
+void acpigen_write_if_and(struct acpi_ctx *ctx, u8 arg1, u8 arg2)
+{
+	acpigen_write_if(ctx);
+	acpigen_emit_byte(ctx, AND_OP);
+	acpigen_emit_byte(ctx, arg1);
+	acpigen_emit_byte(ctx, arg2);
+}
+
+/*
+ * Generates ACPI code for checking if operand1 and operand2 are equal, where,
+ * operand1 is ACPI op and operand2 is an integer.
+ *
+ * If (Lequal (op, val))
+ */
+void acpigen_write_if_lequal_op_int(struct acpi_ctx *ctx, u8 op, u64 val)
+{
+	acpigen_write_if(ctx);
+	acpigen_emit_byte(ctx, LEQUAL_OP);
+	acpigen_emit_byte(ctx, op);
+	acpigen_write_integer(ctx, val);
+}
+
+void acpigen_write_else(struct acpi_ctx *ctx)
+{
+	acpigen_emit_byte(ctx, ELSE_OP);
+	acpigen_write_len_f(ctx);
+}
+
+void acpigen_write_to_buffer(struct acpi_ctx *ctx, u8 src, u8 dst)
+{
+	acpigen_emit_byte(ctx, TO_BUFFER_OP);
+	acpigen_emit_byte(ctx, src);
+	acpigen_emit_byte(ctx, dst);
+}
+
+void acpigen_write_to_integer(struct acpi_ctx *ctx, u8 src, u8 dst)
+{
+	acpigen_emit_byte(ctx, TO_INTEGER_OP);
+	acpigen_emit_byte(ctx, src);
+	acpigen_emit_byte(ctx, dst);
+}
+
+void acpigen_write_byte_buffer(struct acpi_ctx *ctx, u8 *arr, size_t size)
+{
+	size_t i;
+
+	acpigen_emit_byte(ctx, BUFFER_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_write_integer(ctx, size);
+
+	for (i = 0; i < size; i++)
+		acpigen_emit_byte(ctx, arr[i]);
+
+	acpigen_pop_len(ctx);
+}
+
+void acpigen_write_return_byte_buffer(struct acpi_ctx *ctx, u8 *arr,
+				      size_t size)
+{
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_write_byte_buffer(ctx, arr, size);
+}
+
+void acpigen_write_return_singleton_buffer(struct acpi_ctx *ctx, u8 arg)
+{
+	acpigen_write_return_byte_buffer(ctx, &arg, 1);
+}
+
+void acpigen_write_return_byte(struct acpi_ctx *ctx, u8 arg)
+{
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_write_byte(ctx, arg);
+}
+
+void acpigen_write_return_integer(struct acpi_ctx *ctx, u64 arg)
+{
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_write_integer(ctx, arg);
+}
+
+void acpigen_write_return_string(struct acpi_ctx *ctx, const char *arg)
+{
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_write_string(ctx, arg);
+}
+
+void acpigen_write_upc(struct acpi_ctx *ctx, enum acpi_upc_type type)
+{
+	acpigen_write_name(ctx, "_UPC");
+	acpigen_write_package(ctx, 4);
+	/* Connectable */
+	acpigen_write_byte(ctx, type == UPC_TYPE_UNUSED ? 0 : 0xff);
+	/* Type */
+	acpigen_write_byte(ctx, type);
+	/* Reserved0 */
+	acpigen_write_zero(ctx);
+	/* Reserved1 */
+	acpigen_write_zero(ctx);
+	acpigen_pop_len(ctx);
+}
+
+int acpigen_write_dsm(struct acpi_ctx *ctx, const char *uuid,
+		      hid_callback_func callbacks[], size_t count, void *arg)
+{
+	struct dsm_uuid id = DSM_UUID(uuid, callbacks, count, arg);
+	int ret;
+
+	ret = acpigen_write_dsm_uuid_arr(ctx, &id, 1);
+	if (ret)
+		return log_msg_ret("uuid_arr", ret);
+
+	return 0;
+}
+
+static int acpigen_write_dsm_uuid(struct acpi_ctx *ctx, struct dsm_uuid *id)
+{
+	size_t i;
+	int ret;
+
+	/* If (LEqual (Local0, ToUUID(uuid))) */
+	acpigen_write_if(ctx);
+	acpigen_emit_byte(ctx, LEQUAL_OP);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+	ret = acpigen_write_uuid(ctx, id->uuid);
+	if (ret)
+		return log_msg_ret("uuid", ret);
+
+	/* ToInteger (Arg2, Local1) */
+	acpigen_write_to_integer(ctx, ARG2_OP, LOCAL1_OP);
+
+	for (i = 0; i < id->count; i++) {
+		/* If (LEqual (Local1, i)) */
+		acpigen_write_if_lequal_op_int(ctx, LOCAL1_OP, i);
+
+		/* Callback to write if handler. */
+		if (id->callbacks[i])
+			id->callbacks[i](ctx, id->arg);
+
+		acpigen_pop_len(ctx);	/* If */
+	}
+
+	/* Default case: Return (Buffer (One) { 0x0 }) */
+	acpigen_write_return_singleton_buffer(ctx, 0x0);
+
+	acpigen_pop_len(ctx);	/* If (LEqual (Local0, ToUUID(uuid))) */
+
+	return 0;
+}
+
+/*
+ * Generate ACPI AML code for _DSM method.
+ * This function takes as input array of uuid for the device, set of callbacks
+ * and argument to pass into the callbacks. Callbacks should ensure that Local0
+ * and Local1 are left untouched. Use of Local2-Local7 is permitted in
+ * callbacks.
+ *
+ * Arguments passed into _DSM method:
+ * Arg0 = UUID
+ * Arg1 = Revision
+ * Arg2 = Function index
+ * Arg3 = Function specific arguments
+ *
+ * AML code generated would look like:
+ * Method (_DSM, 4, Serialized) {
+ *	ToBuffer (Arg0, Local0)
+ *	If (LEqual (Local0, ToUUID(uuid))) {
+ *		ToInteger (Arg2, Local1)
+ *		If (LEqual (Local1, 0)) {
+ *			<acpigen by callback[0]>
+ *		}
+ *		...
+ *		If (LEqual (Local1, n)) {
+ *			<acpigen by callback[n]>
+ *		}
+ *		Return (Buffer (One) { 0x0 })
+ *	}
+ *	...
+ *	If (LEqual (Local0, ToUUID(uuidn))) {
+ *	...
+ *	}
+ *	Return (Buffer (One) { 0x0 })
+ * }
+ */
+int acpigen_write_dsm_uuid_arr(struct acpi_ctx *ctx, struct dsm_uuid *ids,
+			       size_t count)
+{
+	size_t i;
+	int ret;
+
+	/* Method (_DSM, 4, Serialized) */
+	acpigen_write_method_serialized(ctx, "_DSM", 0x4);
+
+	/* ToBuffer (Arg0, Local0) */
+	acpigen_write_to_buffer(ctx, ARG0_OP, LOCAL0_OP);
+
+	for (i = 0; i < count; i++) {
+		ret = acpigen_write_dsm_uuid(ctx, &ids[i]);
+		if (ret)
+			return ret;
+	}
+
+	/* Return (Buffer (One) { 0x0 }) */
+	acpigen_write_return_singleton_buffer(ctx, 0x0);
+
+	acpigen_pop_len(ctx);	/* Method _DSM */
+
+	return 0;
+}
+
+#define CPPC_PACKAGE_NAME "\\GCPC"
+
+int acpigen_write_cppc_package(struct acpi_ctx *ctx,
+			       const struct cppc_config *config)
+{
+	u32 i;
+	u32 max;
+
+	switch (config->version) {
+	case 1:
+		max = CPPC_MAX_FIELDS_VER_1;
+		break;
+	case 2:
+		max = CPPC_MAX_FIELDS_VER_2;
+		break;
+	case 3:
+		max = CPPC_MAX_FIELDS_VER_3;
+		break;
+	default:
+		log_err("CPPC version %u is not implemented\n",
+			config->version);
+		return -EDOM;
+	}
+	acpigen_write_name(ctx, CPPC_PACKAGE_NAME);
+
+	/* Adding 2 to account for length and version fields */
+	acpigen_write_package(ctx, max + 2);
+	acpigen_write_dword(ctx, max + 2);
+
+	acpigen_write_byte(ctx, config->version);
+
+	for (i = 0; i < max; ++i) {
+		const struct acpi_gen_regaddr *reg = &config->regs[i];
+
+		if (reg->space_id == ACPI_ADDRESS_SPACE_MEMORY &&
+		    reg->bit_width == 32 && reg->access_size == 0) {
+			acpigen_write_dword(ctx, reg->addrl);
+		} else {
+			acpigen_write_register_resource(ctx, reg);
+		}
+	}
+	acpigen_pop_len(ctx);
+
+	return 0;
+}
+
+void acpigen_write_cppc_method(struct acpi_ctx *ctx)
+{
+	acpigen_write_method(ctx, "_CPC", 0);
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_emit_namestring(ctx, CPPC_PACKAGE_NAME);
+	acpigen_pop_len(ctx);
+}
+
+/*
+ * Generate ACPI AML code for _ROM method.
+ * This function takes as input ROM data and ROM length.
+ *
+ * The ACPI spec isn't clear about what should happen at the end of the
+ * ROM. Tests showed that it shouldn't truncate, but fill the remaining
+ * bytes in the returned buffer with zeros.
+ *
+ * Arguments passed into _DSM method:
+ * Arg0 = Offset in Bytes
+ * Arg1 = Bytes to return
+ *
+ * Example:
+ *   acpigen_write_rom(0xdeadbeef, 0x10000)
+ *
+ * AML code generated would look like:
+ * Method (_ROM, 2, NotSerialized) {
+ *
+ *	OperationRegion("ROMS", SYSTEMMEMORY, 0xdeadbeef, 0x10000)
+ *	Field (ROMS, AnyAcc, NoLock, Preserve)
+ *	{
+ *		Offset (0),
+ *		RBF0,   0x80000
+ *	}
+ *
+ *	Store (Arg0, Local0)
+ *	Store (Arg1, Local1)
+ *
+ *	If (LGreater (Local1, 0x1000))
+ *	{
+ *		Store (0x1000, Local1)
+ *	}
+ *
+ *	Store (Local1, Local3)
+ *
+ *	If (LGreater (Local0, 0x10000))
+ *	{
+ *		Return(Buffer(Local1){0})
+ *	}
+ *
+ *	If (LGreater (Local0, 0x0f000))
+ *	{
+ *		Subtract (0x10000, Local0, Local2)
+ *		If (LGreater (Local1, Local2))
+ *		{
+ *			Store (Local2, Local1)
+ *		}
+ *	}
+ *
+ *	Name (ROM1, Buffer (Local3) {0})
+ *
+ *	Multiply (Local0, 0x08, Local0)
+ *	Multiply (Local1, 0x08, Local1)
+ *
+ *	CreateField (RBF0, Local0, Local1, TMPB)
+ *	Store (TMPB, ROM1)
+ *	Return (ROM1)
+ * }
+ */
+int acpigen_write_rom(struct acpi_ctx *ctx, void *bios, const size_t length)
+{
+	int ret;
+
+	assert(bios);
+	assert(length);
+
+	/* Method (_ROM, 2, Serialized) */
+	acpigen_write_method_serialized(ctx, "_ROM", 2);
+
+	/* OperationRegion("ROMS", SYSTEMMEMORY, current, length) */
+	struct opregion opreg = OPREGION("ROMS", SYSTEMMEMORY,
+			(uintptr_t)bios, length);
+	acpigen_write_opregion(ctx, &opreg);
+
+	struct fieldlist l[] = {
+		FIELDLIST_OFFSET(0),
+		FIELDLIST_NAMESTR("RBF0", 8 * length),
+	};
+
+	/*
+	 * Field (ROMS, AnyAcc, NoLock, Preserve)
+	 * {
+	 *  Offset (0),
+	 *  RBF0,   0x80000
+	 * }
+	 */
+	ret = acpigen_write_field(ctx, opreg.name, l, 2, FIELD_ANYACC |
+				  FIELD_NOLOCK | FIELD_PRESERVE);
+	if (ret)
+		return log_msg_ret("field", ret);
+
+	/* Store (Arg0, Local0) */
+	acpigen_write_store(ctx);
+	acpigen_emit_byte(ctx, ARG0_OP);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+
+	/* Store (Arg1, Local1) */
+	acpigen_write_store(ctx);
+	acpigen_emit_byte(ctx, ARG1_OP);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+
+	/* ACPI SPEC requires to return at maximum 4KiB */
+	/* If (LGreater (Local1, 0x1000)) */
+	acpigen_write_if(ctx);
+	acpigen_emit_byte(ctx, LGREATER_OP);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+	acpigen_write_integer(ctx, 0x1000);
+
+	/* Store (0x1000, Local1) */
+	acpigen_write_store(ctx);
+	acpigen_write_integer(ctx, 0x1000);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+
+	/* Pop if */
+	acpigen_pop_len(ctx);
+
+	/* Store (Local1, Local3) */
+	acpigen_write_store(ctx);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+	acpigen_emit_byte(ctx, LOCAL3_OP);
+
+	/* If (LGreater (Local0, length)) */
+	acpigen_write_if(ctx);
+	acpigen_emit_byte(ctx, LGREATER_OP);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+	acpigen_write_integer(ctx, length);
+
+	/* Return(Buffer(Local1){0}) */
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_emit_byte(ctx, BUFFER_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+	acpigen_emit_byte(ctx, 0);
+	acpigen_pop_len(ctx);
+
+	/* Pop if */
+	acpigen_pop_len(ctx);
+
+	/* If (LGreater (Local0, length - 4096)) */
+	acpigen_write_if(ctx);
+	acpigen_emit_byte(ctx, LGREATER_OP);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+	acpigen_write_integer(ctx, length - 4096);
+
+	/* Subtract (length, Local0, Local2) */
+	acpigen_emit_byte(ctx, SUBTRACT_OP);
+	acpigen_write_integer(ctx, length);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+	acpigen_emit_byte(ctx, LOCAL2_OP);
+
+	/* If (LGreater (Local1, Local2)) */
+	acpigen_write_if(ctx);
+	acpigen_emit_byte(ctx, LGREATER_OP);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+	acpigen_emit_byte(ctx, LOCAL2_OP);
+
+	/* Store (Local2, Local1) */
+	acpigen_write_store(ctx);
+	acpigen_emit_byte(ctx, LOCAL2_OP);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+
+	/* Pop if */
+	acpigen_pop_len(ctx);
+
+	/* Pop if */
+	acpigen_pop_len(ctx);
+
+	/* Name (ROM1, Buffer (Local3) {0}) */
+	acpigen_write_name(ctx, "ROM1");
+	acpigen_emit_byte(ctx, BUFFER_OP);
+	acpigen_write_len_f(ctx);
+	acpigen_emit_byte(ctx, LOCAL3_OP);
+	acpigen_emit_byte(ctx, 0);
+	acpigen_pop_len(ctx);
+
+	/* Multiply (Local1, 0x08, Local1) */
+	acpigen_emit_byte(ctx, MULTIPLY_OP);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+	acpigen_write_integer(ctx, 0x08);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+
+	/* Multiply (Local0, 0x08, Local0) */
+	acpigen_emit_byte(ctx, MULTIPLY_OP);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+	acpigen_write_integer(ctx, 0x08);
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+
+	/* CreateField (RBF0, Local0, Local1, TMPB) */
+	acpigen_emit_ext_op(ctx, CREATEFIELD_OP);
+	acpigen_emit_namestring(ctx, "RBF0");
+	acpigen_emit_byte(ctx, LOCAL0_OP);
+	acpigen_emit_byte(ctx, LOCAL1_OP);
+	acpigen_emit_namestring(ctx, "TMPB");
+
+	/* Store (TMPB, ROM1) */
+	acpigen_write_store(ctx);
+	acpigen_emit_namestring(ctx, "TMPB");
+	acpigen_emit_namestring(ctx, "ROM1");
+
+	/* Return (ROM1) */
+	acpigen_emit_byte(ctx, RETURN_OP);
+	acpigen_emit_namestring(ctx, "ROM1");
+
+	/* Pop method */
+	acpigen_pop_len(ctx);
+
+	return 0;
+}
+
+/* Soc-implemented functions -- weak definitions. */
+int __weak acpigen_soc_read_rx_gpio(struct acpi_ctx *ctx, unsigned int gpio_num)
+{
+	log_err("not implemented\n");
+	acpigen_write_debug_string(ctx, "read_rx_gpio not available");
+
+	return -ENOTSUPP;
+}
+
+int __weak acpigen_soc_get_tx_gpio(struct acpi_ctx *ctx, unsigned int gpio_num)
+{
+	log_err("not implemented\n");
+	acpigen_write_debug_string(ctx, "get_tx_gpio not available");
+
+	return -ENOTSUPP;
+}
+
+int __weak acpigen_soc_set_tx_gpio(struct acpi_ctx *ctx, unsigned int gpio_num)
+{
+	log_err("not implemented\n");
+	acpigen_write_debug_string(ctx, "set_tx_gpio not available");
+
+	return -ENOTSUPP;
+}
+
+int __weak acpigen_soc_clear_tx_gpio(struct acpi_ctx *ctx,
+				     unsigned int gpio_num)
+{
+	log_err("not implemented\n");
+	acpigen_write_debug_string(ctx, "clear_tx_gpio not available");
+
+	return -ENOTSUPP;
+}
+
+/*
+ * Helper functions for enabling/disabling Tx GPIOs based on the GPIO
+ * polarity. These functions end up calling acpigen_soc_{set,clear}_tx_gpio to
+ * make callbacks into SoC acpigen code.
+ *
+ * Returns 0 on success and -1 on error.
+ */
+int acpigen_enable_tx_gpio(struct acpi_ctx *ctx, struct acpi_gpio *gpio)
+{
+	int ret;
+
+	if (gpio->polarity == ACPI_GPIO_ACTIVE_HIGH)
+		ret = acpigen_soc_set_tx_gpio(ctx, gpio->pins[0]);
+	else
+		ret = acpigen_soc_clear_tx_gpio(ctx, gpio->pins[0]);
+	if (ret)
+		return log_msg_ret("call", ret);
+
+	return 0;
+}
+
+int acpigen_disable_tx_gpio(struct acpi_ctx *ctx, struct acpi_gpio *gpio)
+{
+	int ret;
+
+	if (gpio->polarity == ACPI_GPIO_ACTIVE_LOW)
+		return acpigen_soc_set_tx_gpio(ctx, gpio->pins[0]);
+	else
+		return acpigen_soc_clear_tx_gpio(ctx, gpio->pins[0]);
+	if (ret)
+		return log_msg_ret("call", ret);
+
+	return 0;
+}