/*
 * Copyright 2015 Freescale Semiconductor, Inc.
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <fsl_validate.h>
#include <fsl_secboot_err.h>
#include <fsl_sfp.h>
#include <fsl_sec.h>
#include <command.h>
#include <malloc.h>
#include <dm/uclass.h>
#include <u-boot/rsa-mod-exp.h>
#include <hash.h>
#include <fsl_secboot_err.h>
#ifndef CONFIG_MPC85xx
#include <asm/arch/immap_ls102xa.h>
#endif

#define SHA256_BITS     256
#define SHA256_BYTES    (256/8)
#define SHA256_NIBBLES  (256/4)
#define NUM_HEX_CHARS   (sizeof(ulong) * 2)

/* This array contains DER value for SHA-256 */
static const u8 hash_identifier[] = { 0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60,
                0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00,
                0x04, 0x20
                };

static u8 hash_val[SHA256_BYTES];
static const u8 barker_code[ESBC_BARKER_LEN] = { 0x68, 0x39, 0x27, 0x81 };

void branch_to_self(void) __attribute__ ((noreturn));

/*
 * This function will put core in infinite loop.
 * This will be called when the ESBC can not proceed further due
 * to some unknown errors.
 */
void branch_to_self(void)
{
        printf("Core is in infinite loop due to errors.\n");
self:
        goto self;
}

#if defined(CONFIG_FSL_ISBC_KEY_EXT)
static u32 check_ie(struct fsl_secboot_img_priv *img)
{
        if (img->hdr.ie_flag)
                return 1;

        return 0;
}

/* This function returns the CSF Header Address of uboot
 * For MPC85xx based platforms, the LAW mapping for NOR
 * flash changes in uboot code. Hence the offset needs
 * to be calculated and added to the new NOR flash base
 * address
 */
#if defined(CONFIG_MPC85xx)
int get_csf_base_addr(ulong *csf_addr, ulong *flash_base_addr)
{
        struct ccsr_gur __iomem *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
        u32 csf_hdr_addr = in_be32(&gur->scratchrw[0]);
        u32 csf_flash_offset = csf_hdr_addr & ~(CONFIG_SYS_PBI_FLASH_BASE);
        ulong flash_addr, addr;
        int found = 0;
        int i = 0;

        for (i = 0; i < CONFIG_SYS_MAX_FLASH_BANKS; i++) {
                flash_addr = flash_info[i].start[0];
                addr = flash_info[i].start[0] + csf_flash_offset;
                if (memcmp((u8 *)addr, barker_code, ESBC_BARKER_LEN) == 0) {
                        debug("Barker found on addr %lx\n", addr);
                        found = 1;
                        break;
                }
        }

        if (!found)
                return -1;

        *csf_addr = addr;
        *flash_base_addr = flash_addr;

        return 0;
}
#else
/* For platforms like LS1020, correct flash address is present in
 * the header. So the function reqturns flash base address as 0
 */
int get_csf_base_addr(ulong *csf_addr, ulong *flash_base_addr)
{
        struct ccsr_gur __iomem *gur = (void *)(CONFIG_SYS_FSL_GUTS_ADDR);
        u32 csf_hdr_addr = in_be32(&gur->scratchrw[0]);

        if (memcmp((u8 *)csf_hdr_addr, barker_code, ESBC_BARKER_LEN))
                return -1;

        *csf_addr = csf_hdr_addr;
        *flash_base_addr = 0;
        return 0;
}
#endif

static int get_ie_info_addr(ulong *ie_addr)
{
        struct fsl_secboot_img_hdr *hdr;
        struct fsl_secboot_sg_table *sg_tbl;
        ulong flash_base_addr, csf_addr;

        if (get_csf_base_addr(&csf_addr, &flash_base_addr))
                return -1;

        hdr = (struct fsl_secboot_img_hdr *)csf_addr;

        /* For SoC's with Trust Architecture v1 with corenet bus
         * the sg table field in CSF header has absolute address
         * for sg table in memory. In other Trust Architecture,
         * this field specifies the offset of sg table from the
         * base address of CSF Header
         */
#if defined(CONFIG_FSL_TRUST_ARCH_v1) && defined(CONFIG_FSL_CORENET)
        sg_tbl = (struct fsl_secboot_sg_table *)
                 (((ulong)hdr->psgtable & ~(CONFIG_SYS_PBI_FLASH_BASE)) +
                  flash_base_addr);
#else
        sg_tbl = (struct fsl_secboot_sg_table *)(csf_addr +
                                                 (ulong)hdr->psgtable);
#endif

        /* IE Key Table is the first entry in the SG Table */
#if defined(CONFIG_MPC85xx)
        *ie_addr = (sg_tbl->src_addr & ~(CONFIG_SYS_PBI_FLASH_BASE)) +
                   flash_base_addr;
#else
        *ie_addr = sg_tbl->src_addr;
#endif

        debug("IE Table address is %lx\n", *ie_addr);
        return 0;
}

#endif

#ifdef CONFIG_KEY_REVOCATION
/* This function checks srk_table_flag in header and set/reset srk_flag.*/
static u32 check_srk(struct fsl_secboot_img_priv *img)
{
        if (img->hdr.len_kr.srk_table_flag & SRK_FLAG)
                return 1;

        return 0;
}

/* This function returns ospr's key_revoc values.*/
static u32 get_key_revoc(void)
{
        struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
        return (sfp_in32(&sfp_regs->ospr) & OSPR_KEY_REVOC_MASK) >>
                OSPR_KEY_REVOC_SHIFT;
}

/* This function checks if selected key is revoked or not.*/
static u32 is_key_revoked(u32 keynum, u32 rev_flag)
{
        if (keynum == UNREVOCABLE_KEY)
                return 0;

        if ((u32)(1 << (ALIGN_REVOC_KEY - keynum)) & rev_flag)
                return 1;

        return 0;
}

/* It validates srk_table key lengths.*/
static u32 validate_srk_tbl(struct srk_table *tbl, u32 num_entries)
{
        int i = 0;
        for (i = 0; i < num_entries; i++) {
                if (!((tbl[i].key_len == 2 * KEY_SIZE_BYTES/4) ||
                      (tbl[i].key_len == 2 * KEY_SIZE_BYTES/2) ||
                      (tbl[i].key_len == 2 * KEY_SIZE_BYTES)))
                        return ERROR_ESBC_CLIENT_HEADER_INV_SRK_ENTRY_KEYLEN;
        }
        return 0;
}
#endif

/* This function return length of public key.*/
static inline u32 get_key_len(struct fsl_secboot_img_priv *img)
{
        return img->key_len;
}

/*
 * Handles the ESBC uboot client header verification failure.
 * This  function  handles all the errors which might occur in the
 * parsing and checking of ESBC uboot client header. It will also
 * set the error bits in the SEC_MON.
 */
static void fsl_secboot_header_verification_failure(void)
{
        struct ccsr_sec_mon_regs *sec_mon_regs = (void *)
                                                (CONFIG_SYS_SEC_MON_ADDR);
        struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
        u32 sts = sec_mon_in32(&sec_mon_regs->hp_stat);

        /* 29th bit of OSPR is ITS */
        u32 its = sfp_in32(&sfp_regs->ospr) >> 2;

        /*
         * Read the SEC_MON status register
         * Read SSM_ST field
         */
        sts = sec_mon_in32(&sec_mon_regs->hp_stat);
        if ((sts & HPSR_SSM_ST_MASK) == HPSR_SSM_ST_TRUST) {
                if (its == 1)
                        change_sec_mon_state(HPSR_SSM_ST_TRUST,
                                             HPSR_SSM_ST_SOFT_FAIL);
                else
                        change_sec_mon_state(HPSR_SSM_ST_TRUST,
                                             HPSR_SSM_ST_NON_SECURE);
        }

        printf("Generating reset request\n");
        do_reset(NULL, 0, 0, NULL);
}

/*
 * Handles the ESBC uboot client image verification failure.
 * This  function  handles all the errors which might occur in the
 * public key hash comparison and signature verification of
 * ESBC uboot client image. It will also
 * set the error bits in the SEC_MON.
 */
static void fsl_secboot_image_verification_failure(void)
{
        struct ccsr_sec_mon_regs *sec_mon_regs = (void *)
                                                (CONFIG_SYS_SEC_MON_ADDR);
        struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
        u32 sts = sec_mon_in32(&sec_mon_regs->hp_stat);

        u32 its = sfp_in32(&sfp_regs->ospr) & ITS_MASK >> ITS_BIT;

        /*
         * Read the SEC_MON status register
         * Read SSM_ST field
         */
        sts = sec_mon_in32(&sec_mon_regs->hp_stat);
        if ((sts & HPSR_SSM_ST_MASK) == HPSR_SSM_ST_TRUST) {
                if (its == 1) {
                        change_sec_mon_state(HPSR_SSM_ST_TRUST,
                                             HPSR_SSM_ST_SOFT_FAIL);

                        printf("Generating reset request\n");
                        do_reset(NULL, 0, 0, NULL);
                } else {
                        change_sec_mon_state(HPSR_SSM_ST_TRUST,
                                             HPSR_SSM_ST_NON_SECURE);
                }
        }
}

static void fsl_secboot_bootscript_parse_failure(void)
{
        fsl_secboot_header_verification_failure();
}

/*
 * Handles the errors in esbc boot.
 * This  function  handles all the errors which might occur in the
 * esbc boot phase. It will call the appropriate api to log the
 * errors and set the error bits in the SEC_MON.
 */
void fsl_secboot_handle_error(int error)
{
        const struct fsl_secboot_errcode *e;

        for (e = fsl_secboot_errcodes; e->errcode != ERROR_ESBC_CLIENT_MAX;
                e++) {
                if (e->errcode == error)
                        printf("ERROR :: %x :: %s\n", error, e->name);
        }

        switch (error) {
        case ERROR_ESBC_CLIENT_HEADER_BARKER:
        case ERROR_ESBC_CLIENT_HEADER_IMG_SIZE:
        case ERROR_ESBC_CLIENT_HEADER_KEY_LEN:
        case ERROR_ESBC_CLIENT_HEADER_SIG_LEN:
        case ERROR_ESBC_CLIENT_HEADER_KEY_LEN_NOT_TWICE_SIG_LEN:
        case ERROR_ESBC_CLIENT_HEADER_KEY_MOD_1:
        case ERROR_ESBC_CLIENT_HEADER_KEY_MOD_2:
        case ERROR_ESBC_CLIENT_HEADER_SIG_KEY_MOD:
        case ERROR_ESBC_CLIENT_HEADER_SG_ESBC_EP:
        case ERROR_ESBC_CLIENT_HEADER_SG_ENTIRES_BAD:
#ifdef CONFIG_KEY_REVOCATION
        case ERROR_ESBC_CLIENT_HEADER_KEY_REVOKED:
        case ERROR_ESBC_CLIENT_HEADER_INVALID_SRK_NUM_ENTRY:
        case ERROR_ESBC_CLIENT_HEADER_INVALID_KEY_NUM:
        case ERROR_ESBC_CLIENT_HEADER_INV_SRK_ENTRY_KEYLEN:
#endif
#if defined(CONFIG_FSL_ISBC_KEY_EXT)
        /*@fallthrough@*/
        case ERROR_ESBC_CLIENT_HEADER_IE_KEY_REVOKED:
        case ERROR_ESBC_CLIENT_HEADER_INVALID_IE_NUM_ENTRY:
        case ERROR_ESBC_CLIENT_HEADER_INVALID_IE_KEY_NUM:
        case ERROR_ESBC_CLIENT_HEADER_INV_IE_ENTRY_KEYLEN:
        case ERROR_IE_TABLE_NOT_FOUND:
#endif
                fsl_secboot_header_verification_failure();
                break;
        case ERROR_ESBC_SEC_RESET:
        case ERROR_ESBC_SEC_DEQ:
        case ERROR_ESBC_SEC_ENQ:
        case ERROR_ESBC_SEC_DEQ_TO:
        case ERROR_ESBC_SEC_JOBQ_STATUS:
        case ERROR_ESBC_CLIENT_HASH_COMPARE_KEY:
        case ERROR_ESBC_CLIENT_HASH_COMPARE_EM:
                fsl_secboot_image_verification_failure();
                break;
        case ERROR_ESBC_MISSING_BOOTM:
                fsl_secboot_bootscript_parse_failure();
                break;
        case ERROR_ESBC_WRONG_CMD:
        default:
                branch_to_self();
                break;
        }
}

static void fsl_secblk_handle_error(int error)
{
        switch (error) {
        case ERROR_ESBC_SEC_ENQ:
                fsl_secboot_handle_error(ERROR_ESBC_SEC_ENQ);
                break;
        case ERROR_ESBC_SEC_DEQ:
                fsl_secboot_handle_error(ERROR_ESBC_SEC_DEQ);
                break;
        case ERROR_ESBC_SEC_DEQ_TO:
                fsl_secboot_handle_error(ERROR_ESBC_SEC_DEQ_TO);
                break;
        default:
                printf("Job Queue Output status %x\n", error);
                fsl_secboot_handle_error(ERROR_ESBC_SEC_JOBQ_STATUS);
                break;
        }
}

/*
 * Calculate hash of key obtained via offset present in ESBC uboot
 * client hdr. This function calculates the hash of key which is obtained
 * through offset present in ESBC uboot client header.
 */
static int calc_img_key_hash(struct fsl_secboot_img_priv *img)
{
        struct hash_algo *algo;
        void *ctx;
        int i, srk = 0;
        int ret = 0;
        const char *algo_name = "sha256";

        /* Calculate hash of the esbc key */
        ret = hash_progressive_lookup_algo(algo_name, &algo);
        if (ret)
                return ret;

        ret = algo->hash_init(algo, &ctx);
        if (ret)
                return ret;

        /* Update hash for ESBC key */
#ifdef CONFIG_KEY_REVOCATION
        if (check_srk(img)) {
                ret = algo->hash_update(algo, ctx,
                        (u8 *)(img->ehdrloc + img->hdr.srk_tbl_off),
                        img->hdr.len_kr.num_srk * sizeof(struct srk_table), 1);
                srk = 1;
        }
#endif
        if (!srk)
                ret = algo->hash_update(algo, ctx,
                        img->img_key, img->key_len, 1);
        if (ret)
                return ret;

        /* Copy hash at destination buffer */
        ret = algo->hash_finish(algo, ctx, hash_val, algo->digest_size);
        if (ret)
                return ret;

        for (i = 0; i < SHA256_BYTES; i++)
                img->img_key_hash[i] = hash_val[i];

        return 0;
}

/*
 * Calculate hash of ESBC hdr and ESBC. This function calculates the
 * single hash of ESBC header and ESBC image. If SG flag is on, all
 * SG entries are also hashed alongwith the complete SG table.
 */
static int calc_esbchdr_esbc_hash(struct fsl_secboot_img_priv *img)
{
        struct hash_algo *algo;
        void *ctx;
        int ret = 0;
        int key_hash = 0;
        const char *algo_name = "sha256";

        /* Calculate the hash of the ESBC */
        ret = hash_progressive_lookup_algo(algo_name, &algo);
        if (ret)
                return ret;

        ret = algo->hash_init(algo, &ctx);
        /* Copy hash at destination buffer */
        if (ret)
                return ret;

        /* Update hash for CSF Header */
        ret = algo->hash_update(algo, ctx,
                (u8 *)&img->hdr, sizeof(struct fsl_secboot_img_hdr), 0);
        if (ret)
                return ret;

        /* Update the hash with that of srk table if srk flag is 1
         * If IE Table is selected, key is not added in the hash
         * If neither srk table nor IE key table available, add key
         * from header in the hash calculation
         */
#ifdef CONFIG_KEY_REVOCATION
        if (check_srk(img)) {
                ret = algo->hash_update(algo, ctx,
                        (u8 *)(img->ehdrloc + img->hdr.srk_tbl_off),
                        img->hdr.len_kr.num_srk * sizeof(struct srk_table), 0);
                key_hash = 1;
        }
#endif
#if defined(CONFIG_FSL_ISBC_KEY_EXT)
        if (!key_hash && check_ie(img))
                key_hash = 1;
#endif
        if (!key_hash)
                ret = algo->hash_update(algo, ctx,
                        img->img_key, img->hdr.key_len, 0);
        if (ret)
                return ret;

        /* Update hash for actual Image */
        ret = algo->hash_update(algo, ctx,
                        (u8 *)img->hdr.pimg, img->hdr.img_size, 1);
        if (ret)
                return ret;

        /* Copy hash at destination buffer */
        ret = algo->hash_finish(algo, ctx, hash_val, algo->digest_size);
        if (ret)
                return ret;

        return 0;
}

/*
 * Construct encoded hash EM' wrt PKCSv1.5. This function calculates the
 * pointers for padding, DER value and hash. And finally, constructs EM'
 * which includes hash of complete CSF header and ESBC image. If SG flag
 * is on, hash of SG table and entries is also included.
 */
static void construct_img_encoded_hash_second(struct fsl_secboot_img_priv *img)
{
        /*
         * RSA PKCSv1.5 encoding format for encoded message is below
         * EM = 0x0 || 0x1 || PS || 0x0 || DER || Hash
         * PS is Padding String
         * DER is DER value for SHA-256
         * Hash is SHA-256 hash
         * *********************************************************
         * representative points to first byte of EM initially and is
         * filled with 0x0
         * representative is incremented by 1 and second byte is filled
         * with 0x1
         * padding points to third byte of EM
         * digest points to full length of EM - 32 bytes
         * hash_id (DER value) points to 19 bytes before pDigest
         * separator is one byte which separates padding and DER
         */

        size_t len;
        u8 *representative;
        u8 *padding, *digest;
        u8 *hash_id, *separator;
        int i;

        len = (get_key_len(img) / 2) - 1;
        representative = img->img_encoded_hash_second;
        representative[0] = 0;
        representative[1] = 1;  /* block type 1 */

        padding = &representative[2];
        digest = &representative[1] + len - 32;
        hash_id = digest - sizeof(hash_identifier);
        separator = hash_id - 1;

        /* fill padding area pointed by padding with 0xff */
        memset(padding, 0xff, separator - padding);

        /* fill byte pointed by separator */
        *separator = 0;

        /* fill SHA-256 DER value  pointed by HashId */
        memcpy(hash_id, hash_identifier, sizeof(hash_identifier));

        /* fill hash pointed by Digest */
        for (i = 0; i < SHA256_BYTES; i++)
                digest[i] = hash_val[i];
}

/*
 * Reads and validates the ESBC client header.
 * This function reads key and signature from the ESBC client header.
 * If Scatter/Gather flag is on, lengths and offsets of images
 * present as SG entries are also read. This function also checks
 * whether the header is valid or not.
 */
static int read_validate_esbc_client_header(struct fsl_secboot_img_priv *img)
{
        char buf[20];
        struct fsl_secboot_img_hdr *hdr = &img->hdr;
        void *esbc = (u8 *)img->ehdrloc;
        u8 *k, *s;
#ifdef CONFIG_KEY_REVOCATION
        u32 ret;
        u32 key_num, key_revoc_flag, size;
#endif
#if defined(CONFIG_FSL_ISBC_KEY_EXT)
        struct ie_key_info *ie_info;
        u32 ie_num, ie_revoc_flag, ie_key_len;
#endif
        int  key_found = 0;

        /* check barker code */
        if (memcmp(hdr->barker, barker_code, ESBC_BARKER_LEN))
                return ERROR_ESBC_CLIENT_HEADER_BARKER;

        sprintf(buf, "%p", hdr->pimg);
        setenv("img_addr", buf);

        if (!hdr->img_size)
                return ERROR_ESBC_CLIENT_HEADER_IMG_SIZE;

        /* Key checking*/
#ifdef CONFIG_KEY_REVOCATION
        if (check_srk(img)) {
                if ((hdr->len_kr.num_srk == 0) ||
                    (hdr->len_kr.num_srk > MAX_KEY_ENTRIES))
                        return ERROR_ESBC_CLIENT_HEADER_INVALID_SRK_NUM_ENTRY;

                key_num = hdr->len_kr.srk_sel;
                if (key_num == 0 || key_num > hdr->len_kr.num_srk)
                        return ERROR_ESBC_CLIENT_HEADER_INVALID_KEY_NUM;

                /* Get revoc key from sfp */
                key_revoc_flag = get_key_revoc();
                ret = is_key_revoked(key_num, key_revoc_flag);
                if (ret)
                        return ERROR_ESBC_CLIENT_HEADER_KEY_REVOKED;

                size = hdr->len_kr.num_srk * sizeof(struct srk_table);

                memcpy(&img->srk_tbl, esbc + hdr->srk_tbl_off, size);

                ret = validate_srk_tbl(img->srk_tbl, hdr->len_kr.num_srk);

                if (ret != 0)
                        return ret;

                img->key_len = img->srk_tbl[key_num - 1].key_len;

                memcpy(&img->img_key, &(img->srk_tbl[key_num - 1].pkey),
                       img->key_len);

                key_found = 1;
        }
#endif

#if defined(CONFIG_FSL_ISBC_KEY_EXT)
        if (!key_found && check_ie(img)) {
                if (get_ie_info_addr(&img->ie_addr))
                        return ERROR_IE_TABLE_NOT_FOUND;
                ie_info = (struct ie_key_info *)img->ie_addr;
                if (ie_info->num_keys == 0 || ie_info->num_keys > 32)
                        return ERROR_ESBC_CLIENT_HEADER_INVALID_IE_NUM_ENTRY;

                ie_num = hdr->ie_key_sel;
                if (ie_num == 0 || ie_num > ie_info->num_keys)
                        return ERROR_ESBC_CLIENT_HEADER_INVALID_IE_KEY_NUM;

                ie_revoc_flag = ie_info->key_revok;
                if ((u32)(1 << (ie_num - 1)) & ie_revoc_flag)
                        return ERROR_ESBC_CLIENT_HEADER_IE_KEY_REVOKED;

                ie_key_len = ie_info->ie_key_tbl[ie_num - 1].key_len;

                if (!((ie_key_len == 2 * KEY_SIZE_BYTES / 4) ||
                      (ie_key_len == 2 * KEY_SIZE_BYTES / 2) ||
                      (ie_key_len == 2 * KEY_SIZE_BYTES)))
                        return ERROR_ESBC_CLIENT_HEADER_INV_IE_ENTRY_KEYLEN;

                memcpy(&img->img_key, &(ie_info->ie_key_tbl[ie_num - 1].pkey),
                       ie_key_len);

                img->key_len = ie_key_len;
                key_found = 1;
        }
#endif

        if (key_found == 0) {
                /* check key length */
                if (!((hdr->key_len == 2 * KEY_SIZE_BYTES / 4) ||
                      (hdr->key_len == 2 * KEY_SIZE_BYTES / 2) ||
                      (hdr->key_len == 2 * KEY_SIZE_BYTES)))
                        return ERROR_ESBC_CLIENT_HEADER_KEY_LEN;

                memcpy(&img->img_key, esbc + hdr->pkey, hdr->key_len);

                img->key_len = hdr->key_len;

                key_found = 1;
        }

        /* check signaure */
        if (get_key_len(img) == 2 * hdr->sign_len) {
                /* check signature length */
                if (!((hdr->sign_len == KEY_SIZE_BYTES / 4) ||
                      (hdr->sign_len == KEY_SIZE_BYTES / 2) ||
                      (hdr->sign_len == KEY_SIZE_BYTES)))
                        return ERROR_ESBC_CLIENT_HEADER_SIG_LEN;
        } else {
                return ERROR_ESBC_CLIENT_HEADER_KEY_LEN_NOT_TWICE_SIG_LEN;
        }

        memcpy(&img->img_sign, esbc + hdr->psign, hdr->sign_len);

        /* No SG support */
        if (hdr->sg_flag)
                return ERROR_ESBC_CLIENT_HEADER_SG;

        /* modulus most significant bit should be set */
        k = (u8 *)&img->img_key;

        if ((k[0] & 0x80) == 0)
                return ERROR_ESBC_CLIENT_HEADER_KEY_MOD_1;

        /* modulus value should be odd */
        if ((k[get_key_len(img) / 2 - 1] & 0x1) == 0)
                return ERROR_ESBC_CLIENT_HEADER_KEY_MOD_2;

        /* Check signature value < modulus value */
        s = (u8 *)&img->img_sign;

        if (!(memcmp(s, k, hdr->sign_len) < 0))
                return ERROR_ESBC_CLIENT_HEADER_SIG_KEY_MOD;

        return ESBC_VALID_HDR;
}

static inline int str2longbe(const char *p, ulong *num)
{
        char *endptr;
        ulong tmp;

        if (!p) {
                return 0;
        } else {
                tmp = simple_strtoul(p, &endptr, 16);
                if (sizeof(ulong) == 4)
                        *num = cpu_to_be32(tmp);
                else
                        *num = cpu_to_be64(tmp);
        }

        return *p != '\0' && *endptr == '\0';
}

int fsl_secboot_validate(cmd_tbl_t *cmdtp, int flag, int argc,
                char * const argv[])
{
        struct ccsr_sfp_regs *sfp_regs = (void *)(CONFIG_SYS_SFP_ADDR);
        ulong hash[SHA256_BYTES/sizeof(ulong)];
        char hash_str[NUM_HEX_CHARS + 1];
        ulong addr = simple_strtoul(argv[1], NULL, 16);
        struct fsl_secboot_img_priv *img;
        struct fsl_secboot_img_hdr *hdr;
        void *esbc;
        int ret, i, hash_cmd = 0;
        u32 srk_hash[8];
        uint32_t key_len;
        struct key_prop prop;
#if !defined(USE_HOSTCC)
        struct udevice *mod_exp_dev;
#endif

        if (argc == 3) {
                char *cp = argv[2];
                int i = 0;

                if (*cp == '0' && *(cp + 1) == 'x')
                        cp += 2;

                /* The input string expected is in hex, where
                 * each 4 bits would be represented by a hex
                 * sha256 hash is 256 bits long, which would mean
                 * num of characters = 256 / 4
                 */
                if (strlen(cp) != SHA256_NIBBLES) {
                        printf("%s is not a 256 bits hex string as expected\n",
                               argv[2]);
                        return -1;
                }

                for (i = 0; i < sizeof(hash)/sizeof(ulong); i++) {
                        strncpy(hash_str, cp + (i * NUM_HEX_CHARS),
                                NUM_HEX_CHARS);
                        hash_str[NUM_HEX_CHARS] = '\0';
                        if (!str2longbe(hash_str, &hash[i])) {
                                printf("%s is not a 256 bits hex string ",
                                       argv[2]);
                                return -1;
                        }
                }

                hash_cmd = 1;
        }

        img = malloc(sizeof(struct fsl_secboot_img_priv));

        if (!img)
                return -1;

        memset(img, 0, sizeof(struct fsl_secboot_img_priv));

        hdr = &img->hdr;
        img->ehdrloc = addr;
        esbc = (u8 *)img->ehdrloc;

        memcpy(hdr, esbc, sizeof(struct fsl_secboot_img_hdr));

        /* read and validate esbc header */
        ret = read_validate_esbc_client_header(img);

        if (ret != ESBC_VALID_HDR) {
                fsl_secboot_handle_error(ret);
                goto exit;
        }

        /* SRKH present in SFP */
        for (i = 0; i < NUM_SRKH_REGS; i++)
                srk_hash[i] = srk_in32(&sfp_regs->srk_hash[i]);

        /*
         * Calculate hash of key obtained via offset present in
         * ESBC uboot client hdr
         */
        ret = calc_img_key_hash(img);
        if (ret) {
                fsl_secblk_handle_error(ret);
                goto exit;
        }

        /* Compare hash obtained above with SRK hash present in SFP */
        if (hash_cmd)
                ret = memcmp(&hash, &img->img_key_hash, SHA256_BYTES);
        else
                ret = memcmp(srk_hash, img->img_key_hash, SHA256_BYTES);

#if defined(CONFIG_FSL_ISBC_KEY_EXT)
        if (!hash_cmd && check_ie(img))
                ret = 0;
#endif

        if (ret != 0) {
                fsl_secboot_handle_error(ERROR_ESBC_CLIENT_HASH_COMPARE_KEY);
                goto exit;
        }

        ret = calc_esbchdr_esbc_hash(img);
        if (ret) {
                fsl_secblk_handle_error(ret);
                goto exit;
        }

        /* Construct encoded hash EM' wrt PKCSv1.5 */
        construct_img_encoded_hash_second(img);

        /* Fill prop structure for public key */
        memset(&prop, 0, sizeof(struct key_prop));
        key_len = get_key_len(img) / 2;
        prop.modulus = img->img_key;
        prop.public_exponent = img->img_key + key_len;
        prop.num_bits = key_len * 8;
        prop.exp_len = key_len;

        ret = uclass_get_device(UCLASS_MOD_EXP, 0, &mod_exp_dev);
        if (ret) {
                printf("RSA: Can't find Modular Exp implementation\n");
                return -EINVAL;
        }

        ret = rsa_mod_exp(mod_exp_dev, img->img_sign, img->hdr.sign_len,
                          &prop, img->img_encoded_hash);
        if (ret) {
                fsl_secblk_handle_error(ret);
                goto exit;
        }

        /*
         * compare the encoded messages EM' and EM wrt RSA PKCSv1.5
         * memcmp returns zero on success
         * memcmp returns non-zero on failure
         */
        ret = memcmp(&img->img_encoded_hash_second, &img->img_encoded_hash,
                img->hdr.sign_len);

        if (ret) {
                fsl_secboot_handle_error(ERROR_ESBC_CLIENT_HASH_COMPARE_EM);
                goto exit;
        }

        printf("esbc_validate command successful\n");

exit:
        return 0;
}