/*
 * Copyright (c) 2015, Linaro Limited
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */
#ifndef __LINUX_ARM_SMCCC_H
#define __LINUX_ARM_SMCCC_H

#include <linux/linkage.h>
#include <linux/types.h>
#include <uapi/linux/const.h>

/*
 * This file provides common defines for ARM SMC Calling Convention as
 * specified in
 * http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html
 */

#define ARM_SMCCC_STD_CALL	        _AC(0,U)
#define ARM_SMCCC_FAST_CALL	        _AC(1,U)
#define ARM_SMCCC_TYPE_SHIFT		31

#define ARM_SMCCC_SMC_32		0
#define ARM_SMCCC_SMC_64		1
#define ARM_SMCCC_CALL_CONV_SHIFT	30

#define ARM_SMCCC_OWNER_MASK		0x3F
#define ARM_SMCCC_OWNER_SHIFT		24

#define ARM_SMCCC_FUNC_MASK		0xFFFF

#define ARM_SMCCC_IS_FAST_CALL(smc_val)	\
	((smc_val) & (ARM_SMCCC_FAST_CALL << ARM_SMCCC_TYPE_SHIFT))
#define ARM_SMCCC_IS_64(smc_val) \
	((smc_val) & (ARM_SMCCC_SMC_64 << ARM_SMCCC_CALL_CONV_SHIFT))
#define ARM_SMCCC_FUNC_NUM(smc_val)	((smc_val) & ARM_SMCCC_FUNC_MASK)
#define ARM_SMCCC_OWNER_NUM(smc_val) \
	(((smc_val) >> ARM_SMCCC_OWNER_SHIFT) & ARM_SMCCC_OWNER_MASK)

#define ARM_SMCCC_CALL_VAL(type, calling_convention, owner, func_num) \
	(((type) << ARM_SMCCC_TYPE_SHIFT) | \
	((calling_convention) << ARM_SMCCC_CALL_CONV_SHIFT) | \
	(((owner) & ARM_SMCCC_OWNER_MASK) << ARM_SMCCC_OWNER_SHIFT) | \
	((func_num) & ARM_SMCCC_FUNC_MASK))

#define ARM_SMCCC_OWNER_ARCH		0
#define ARM_SMCCC_OWNER_CPU		1
#define ARM_SMCCC_OWNER_SIP		2
#define ARM_SMCCC_OWNER_OEM		3
#define ARM_SMCCC_OWNER_STANDARD	4
#define ARM_SMCCC_OWNER_TRUSTED_APP	48
#define ARM_SMCCC_OWNER_TRUSTED_APP_END	49
#define ARM_SMCCC_OWNER_TRUSTED_OS	50
#define ARM_SMCCC_OWNER_TRUSTED_OS_END	63

#define ARM_SMCCC_VERSION_1_0		0x10000
#define ARM_SMCCC_VERSION_1_1		0x10001

#define ARM_SMCCC_VERSION_FUNC_ID					\
	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
			   ARM_SMCCC_SMC_32,				\
			   0, 0)

#define ARM_SMCCC_ARCH_FEATURES_FUNC_ID					\
	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
			   ARM_SMCCC_SMC_32,				\
			   0, 1)

#define ARM_SMCCC_ARCH_WORKAROUND_1					\
	ARM_SMCCC_CALL_VAL(ARM_SMCCC_FAST_CALL,				\
			   ARM_SMCCC_SMC_32,				\
			   0, 0x8000)

/**
 * struct arm_smccc_res - Result from SMC/HVC call
 * @a0-a3 result values from registers 0 to 3
 */
struct arm_smccc_res {
	unsigned long a0;
	unsigned long a1;
	unsigned long a2;
	unsigned long a3;
};

/**
 * arm_smccc_smc() - make SMC calls
 * @a0-a7: arguments passed in registers 0 to 7
 * @res: result values from registers 0 to 3
 *
 * This function is used to make SMC calls following SMC Calling Convention.
 * The content of the supplied param are copied to registers 0 to 7 prior
 * to the SMC instruction. The return values are updated with the content
 * from register 0 to 3 on return from the SMC instruction.
 */
asmlinkage void arm_smccc_smc(unsigned long a0, unsigned long a1,
			unsigned long a2, unsigned long a3, unsigned long a4,
			unsigned long a5, unsigned long a6, unsigned long a7,
			struct arm_smccc_res *res);

/**
 * arm_smccc_hvc() - make HVC calls
 * @a0-a7: arguments passed in registers 0 to 7
 * @res: result values from registers 0 to 3
 *
 * This function is used to make HVC calls following SMC Calling
 * Convention.  The content of the supplied param are copied to registers 0
 * to 7 prior to the HVC instruction. The return values are updated with
 * the content from register 0 to 3 on return from the HVC instruction.
 */
asmlinkage void arm_smccc_hvc(unsigned long a0, unsigned long a1,
			unsigned long a2, unsigned long a3, unsigned long a4,
			unsigned long a5, unsigned long a6, unsigned long a7,
			struct arm_smccc_res *res);

/* SMCCC v1.1 implementation madness follows */
#ifdef CONFIG_ARM64

#define SMCCC_SMC_INST	"smc	#0"
#define SMCCC_HVC_INST	"hvc	#0"
#define SMCCC_REG(n)	asm("x" # n)

#elif defined(CONFIG_ARM)
#include <asm/opcodes-sec.h>
#include <asm/opcodes-virt.h>

#define SMCCC_SMC_INST	__SMC(0)
#define SMCCC_HVC_INST	__HVC(0)
#define SMCCC_REG(n)	asm("r" # n)

#endif

#define ___count_args(_0, _1, _2, _3, _4, _5, _6, _7, _8, x, ...) x

#define __count_args(...)						\
	___count_args(__VA_ARGS__, 7, 6, 5, 4, 3, 2, 1, 0)

#define __constraint_write_0						\
	"+r" (r0), "=&r" (r1), "=&r" (r2), "=&r" (r3)
#define __constraint_write_1						\
	"+r" (r0), "+r" (r1), "=&r" (r2), "=&r" (r3)
#define __constraint_write_2						\
	"+r" (r0), "+r" (r1), "+r" (r2), "=&r" (r3)
#define __constraint_write_3						\
	"+r" (r0), "+r" (r1), "+r" (r2), "+r" (r3)
#define __constraint_write_4	__constraint_write_3
#define __constraint_write_5	__constraint_write_4
#define __constraint_write_6	__constraint_write_5
#define __constraint_write_7	__constraint_write_6

#define __constraint_read_0
#define __constraint_read_1
#define __constraint_read_2
#define __constraint_read_3
#define __constraint_read_4	"r" (r4)
#define __constraint_read_5	__constraint_read_4, "r" (r5)
#define __constraint_read_6	__constraint_read_5, "r" (r6)
#define __constraint_read_7	__constraint_read_6, "r" (r7)

#define __declare_arg_0(a0, res)					\
	struct arm_smccc_res   *___res = res;				\
	register u32           r0 SMCCC_REG(0) = a0;			\
	register unsigned long r1 SMCCC_REG(1);				\
	register unsigned long r2 SMCCC_REG(2);				\
	register unsigned long r3 SMCCC_REG(3)

#define __declare_arg_1(a0, a1, res)					\
	struct arm_smccc_res   *___res = res;				\
	register u32           r0 SMCCC_REG(0) = a0;			\
	register typeof(a1)    r1 SMCCC_REG(1) = a1;			\
	register unsigned long r2 SMCCC_REG(2);				\
	register unsigned long r3 SMCCC_REG(3)

#define __declare_arg_2(a0, a1, a2, res)				\
	struct arm_smccc_res   *___res = res;				\
	register u32           r0 SMCCC_REG(0) = a0;			\
	register typeof(a1)    r1 SMCCC_REG(1) = a1;			\
	register typeof(a2)    r2 SMCCC_REG(2) = a2;			\
	register unsigned long r3 SMCCC_REG(3)

#define __declare_arg_3(a0, a1, a2, a3, res)				\
	struct arm_smccc_res   *___res = res;				\
	register u32           r0 SMCCC_REG(0) = a0;			\
	register typeof(a1)    r1 SMCCC_REG(1) = a1;			\
	register typeof(a2)    r2 SMCCC_REG(2) = a2;			\
	register typeof(a3)    r3 SMCCC_REG(3) = a3

#define __declare_arg_4(a0, a1, a2, a3, a4, res)			\
	__declare_arg_3(a0, a1, a2, a3, res);				\
	register typeof(a4) r4 SMCCC_REG(4) = a4

#define __declare_arg_5(a0, a1, a2, a3, a4, a5, res)			\
	__declare_arg_4(a0, a1, a2, a3, a4, res);			\
	register typeof(a5) r5 SMCCC_REG(5) = a5

#define __declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res)		\
	__declare_arg_5(a0, a1, a2, a3, a4, a5, res);			\
	register typeof(a6) r6 SMCCC_REG(6) = a6

#define __declare_arg_7(a0, a1, a2, a3, a4, a5, a6, a7, res)		\
	__declare_arg_6(a0, a1, a2, a3, a4, a5, a6, res);		\
	register typeof(a7) r7 SMCCC_REG(7) = a7

#define ___declare_args(count, ...) __declare_arg_ ## count(__VA_ARGS__)
#define __declare_args(count, ...)  ___declare_args(count, __VA_ARGS__)

#define ___constraints(count)						\
	: __constraint_write_ ## count					\
	: __constraint_read_ ## count					\
	: "memory"
#define __constraints(count)	___constraints(count)

/*
 * We have an output list that is not necessarily used, and GCC feels
 * entitled to optimise the whole sequence away. "volatile" is what
 * makes it stick.
 */
#define __arm_smccc_1_1(inst, ...)					\
	do {								\
		__declare_args(__count_args(__VA_ARGS__), __VA_ARGS__);	\
		asm volatile(inst "\n"					\
			     __constraints(__count_args(__VA_ARGS__)));	\
		if (___res)						\
			*___res = (typeof(*___res)){r0, r1, r2, r3};	\
	} while (0)

/*
 * arm_smccc_1_1_smc() - make an SMCCC v1.1 compliant SMC call
 *
 * This is a variadic macro taking one to eight source arguments, and
 * an optional return structure.
 *
 * @a0-a7: arguments passed in registers 0 to 7
 * @res: result values from registers 0 to 3
 *
 * This macro is used to make SMC calls following SMC Calling Convention v1.1.
 * The content of the supplied param are copied to registers 0 to 7 prior
 * to the SMC instruction. The return values are updated with the content
 * from register 0 to 3 on return from the SMC instruction if not NULL.
 */
#define arm_smccc_1_1_smc(...)	__arm_smccc_1_1(SMCCC_SMC_INST, __VA_ARGS__)

/*
 * arm_smccc_1_1_hvc() - make an SMCCC v1.1 compliant HVC call
 *
 * This is a variadic macro taking one to eight source arguments, and
 * an optional return structure.
 *
 * @a0-a7: arguments passed in registers 0 to 7
 * @res: result values from registers 0 to 3
 *
 * This macro is used to make HVC calls following SMC Calling Convention v1.1.
 * The content of the supplied param are copied to registers 0 to 7 prior
 * to the HVC instruction. The return values are updated with the content
 * from register 0 to 3 on return from the HVC instruction if not NULL.
 */
#define arm_smccc_1_1_hvc(...)	__arm_smccc_1_1(SMCCC_HVC_INST, __VA_ARGS__)

#endif /*__LINUX_ARM_SMCCC_H*/