/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2023 ARM Ltd.
 */

#ifndef __ASM_RSI_CMDS_H
#define __ASM_RSI_CMDS_H

#include <linux/arm-smccc.h>
#include <linux/string.h>
#include <asm/memory.h>

#include <asm/rsi_smc.h>

#define RSI_GRANULE_SHIFT               12
#define RSI_GRANULE_SIZE                (_AC(1, UL) << RSI_GRANULE_SHIFT)

enum ripas {
        RSI_RIPAS_EMPTY = 0,
        RSI_RIPAS_RAM = 1,
        RSI_RIPAS_DESTROYED = 2,
        RSI_RIPAS_DEV = 3,
};

static inline unsigned long rsi_request_version(unsigned long req,
                                                unsigned long *out_lower,
                                                unsigned long *out_higher)
{
        struct arm_smccc_res res;

        arm_smccc_smc(SMC_RSI_ABI_VERSION, req, 0, 0, 0, 0, 0, 0, &res);

        if (out_lower)
                *out_lower = res.a1;
        if (out_higher)
                *out_higher = res.a2;

        return res.a0;
}

static inline unsigned long rsi_get_realm_config(struct realm_config *cfg)
{
        struct arm_smccc_res res;

        arm_smccc_smc(SMC_RSI_REALM_CONFIG, virt_to_phys(cfg),
                      0, 0, 0, 0, 0, 0, &res);
        return res.a0;
}

static inline unsigned long rsi_ipa_state_get(phys_addr_t start,
                                              phys_addr_t end,
                                              enum ripas *state,
                                              phys_addr_t *top)
{
        struct arm_smccc_res res;

        arm_smccc_smc(SMC_RSI_IPA_STATE_GET,
                      start, end, 0, 0, 0, 0, 0,
                      &res);

        if (res.a0 == RSI_SUCCESS) {
                if (top)
                        *top = res.a1;
                if (state)
                        *state = res.a2;
        }

        return res.a0;
}

static inline long rsi_set_addr_range_state(phys_addr_t start,
                                            phys_addr_t end,
                                            enum ripas state,
                                            unsigned long flags,
                                            phys_addr_t *top)
{
        struct arm_smccc_res res;

        arm_smccc_smc(SMC_RSI_IPA_STATE_SET, start, end, state,
                      flags, 0, 0, 0, &res);

        if (top)
                *top = res.a1;

        if (res.a2 != RSI_ACCEPT)
                return -EPERM;

        return res.a0;
}

/**
 * rsi_attestation_token_init - Initialise the operation to retrieve an
 * attestation token.
 *
 * @challenge:  The challenge data to be used in the attestation token
 *              generation.
 * @size:       Size of the challenge data in bytes.
 *
 * Initialises the attestation token generation and returns an upper bound
 * on the attestation token size that can be used to allocate an adequate
 * buffer. The caller is expected to subsequently call
 * rsi_attestation_token_continue() to retrieve the attestation token data on
 * the same CPU.
 *
 * Returns:
 *  On success, returns the upper limit of the attestation report size.
 *  Otherwise, -EINVAL
 */
static inline long
rsi_attestation_token_init(const u8 *challenge, unsigned long size)
{
        struct arm_smccc_1_2_regs regs = { 0 };

        /* The challenge must be at least 32bytes and at most 64bytes */
        if (!challenge || size < 32 || size > 64)
                return -EINVAL;

        regs.a0 = SMC_RSI_ATTESTATION_TOKEN_INIT;
        memcpy(&regs.a1, challenge, size);
        arm_smccc_1_2_smc(&regs, &regs);

        if (regs.a0 == RSI_SUCCESS)
                return regs.a1;

        return -EINVAL;
}

/**
 * rsi_attestation_token_continue - Continue the operation to retrieve an
 * attestation token.
 *
 * @granule: {I}PA of the Granule to which the token will be written.
 * @offset:  Offset within Granule to start of buffer in bytes.
 * @size:    The size of the buffer.
 * @len:     The number of bytes written to the buffer.
 *
 * Retrieves up to a RSI_GRANULE_SIZE worth of token data per call. The caller
 * is expected to call rsi_attestation_token_init() before calling this
 * function to retrieve the attestation token.
 *
 * Return:
 * * %RSI_SUCCESS     - Attestation token retrieved successfully.
 * * %RSI_INCOMPLETE  - Token generation is not complete.
 * * %RSI_ERROR_INPUT - A parameter was not valid.
 * * %RSI_ERROR_STATE - Attestation not in progress.
 */
static inline unsigned long rsi_attestation_token_continue(phys_addr_t granule,
                                                           unsigned long offset,
                                                           unsigned long size,
                                                           unsigned long *len)
{
        struct arm_smccc_res res;

        arm_smccc_1_1_invoke(SMC_RSI_ATTESTATION_TOKEN_CONTINUE,
                             granule, offset, size, 0, &res);

        if (len)
                *len = res.a1;
        return res.a0;
}

#endif /* __ASM_RSI_CMDS_H */