/*
 * sun4i-ss-cipher.c - hardware cryptographic accelerator for Allwinner A20 SoC
 *
 * Copyright (C) 2013-2015 Corentin LABBE <clabbe.montjoie@gmail.com>
 *
 * This file add support for AES cipher with 128,192,256 bits
 * keysize in CBC and ECB mode.
 * Add support also for DES and 3DES in CBC and ECB mode.
 *
 * You could find the datasheet in Documentation/arm/sunxi/README
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */
#include "sun4i-ss.h"

static int sun4i_ss_opti_poll(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_ss_ctx *ss = op->ss;
        unsigned int ivsize = crypto_skcipher_ivsize(tfm);
        struct sun4i_cipher_req_ctx *ctx = skcipher_request_ctx(areq);
        u32 mode = ctx->mode;
        /* when activating SS, the default FIFO space is SS_RX_DEFAULT(32) */
        u32 rx_cnt = SS_RX_DEFAULT;
        u32 tx_cnt = 0;
        u32 spaces;
        u32 v;
        int err = 0;
        unsigned int i;
        unsigned int ileft = areq->cryptlen;
        unsigned int oleft = areq->cryptlen;
        unsigned int todo;
        struct sg_mapping_iter mi, mo;
        unsigned int oi, oo; /* offset for in and out */
        unsigned long flags;

        if (!areq->cryptlen)
                return 0;

        if (!areq->iv) {
                dev_err_ratelimited(ss->dev, "ERROR: Empty IV\n");
                return -EINVAL;
        }

        if (!areq->src || !areq->dst) {
                dev_err_ratelimited(ss->dev, "ERROR: Some SGs are NULL\n");
                return -EINVAL;
        }

        spin_lock_irqsave(&ss->slock, flags);

        for (i = 0; i < op->keylen; i += 4)
                writel(*(op->key + i / 4), ss->base + SS_KEY0 + i);

        if (areq->iv) {
                for (i = 0; i < 4 && i < ivsize / 4; i++) {
                        v = *(u32 *)(areq->iv + i * 4);
                        writel(v, ss->base + SS_IV0 + i * 4);
                }
        }
        writel(mode, ss->base + SS_CTL);

        sg_miter_start(&mi, areq->src, sg_nents(areq->src),
                       SG_MITER_FROM_SG | SG_MITER_ATOMIC);
        sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
                       SG_MITER_TO_SG | SG_MITER_ATOMIC);
        sg_miter_next(&mi);
        sg_miter_next(&mo);
        if (!mi.addr || !mo.addr) {
                dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
                err = -EINVAL;
                goto release_ss;
        }

        ileft = areq->cryptlen / 4;
        oleft = areq->cryptlen / 4;
        oi = 0;
        oo = 0;
        do {
                todo = min3(rx_cnt, ileft, (mi.length - oi) / 4);
                if (todo) {
                        ileft -= todo;
                        writesl(ss->base + SS_RXFIFO, mi.addr + oi, todo);
                        oi += todo * 4;
                }
                if (oi == mi.length) {
                        sg_miter_next(&mi);
                        oi = 0;
                }

                spaces = readl(ss->base + SS_FCSR);
                rx_cnt = SS_RXFIFO_SPACES(spaces);
                tx_cnt = SS_TXFIFO_SPACES(spaces);

                todo = min3(tx_cnt, oleft, (mo.length - oo) / 4);
                if (todo) {
                        oleft -= todo;
                        readsl(ss->base + SS_TXFIFO, mo.addr + oo, todo);
                        oo += todo * 4;
                }
                if (oo == mo.length) {
                        sg_miter_next(&mo);
                        oo = 0;
                }
        } while (oleft);

        if (areq->iv) {
                for (i = 0; i < 4 && i < ivsize / 4; i++) {
                        v = readl(ss->base + SS_IV0 + i * 4);
                        *(u32 *)(areq->iv + i * 4) = v;
                }
        }

release_ss:
        sg_miter_stop(&mi);
        sg_miter_stop(&mo);
        writel(0, ss->base + SS_CTL);
        spin_unlock_irqrestore(&ss->slock, flags);
        return err;
}

/* Generic function that support SG with size not multiple of 4 */
static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_ss_ctx *ss = op->ss;
        int no_chunk = 1;
        struct scatterlist *in_sg = areq->src;
        struct scatterlist *out_sg = areq->dst;
        unsigned int ivsize = crypto_skcipher_ivsize(tfm);
        struct sun4i_cipher_req_ctx *ctx = skcipher_request_ctx(areq);
        u32 mode = ctx->mode;
        /* when activating SS, the default FIFO space is SS_RX_DEFAULT(32) */
        u32 rx_cnt = SS_RX_DEFAULT;
        u32 tx_cnt = 0;
        u32 v;
        u32 spaces;
        int err = 0;
        unsigned int i;
        unsigned int ileft = areq->cryptlen;
        unsigned int oleft = areq->cryptlen;
        unsigned int todo;
        struct sg_mapping_iter mi, mo;
        unsigned int oi, oo;    /* offset for in and out */
        char buf[4 * SS_RX_MAX];/* buffer for linearize SG src */
        char bufo[4 * SS_TX_MAX]; /* buffer for linearize SG dst */
        unsigned int ob = 0;    /* offset in buf */
        unsigned int obo = 0;   /* offset in bufo*/
        unsigned int obl = 0;   /* length of data in bufo */
        unsigned long flags;

        if (!areq->cryptlen)
                return 0;

        if (!areq->iv) {
                dev_err_ratelimited(ss->dev, "ERROR: Empty IV\n");
                return -EINVAL;
        }

        if (!areq->src || !areq->dst) {
                dev_err_ratelimited(ss->dev, "ERROR: Some SGs are NULL\n");
                return -EINVAL;
        }

        /*
         * if we have only SGs with size multiple of 4,
         * we can use the SS optimized function
         */
        while (in_sg && no_chunk == 1) {
                if (in_sg->length % 4)
                        no_chunk = 0;
                in_sg = sg_next(in_sg);
        }
        while (out_sg && no_chunk == 1) {
                if (out_sg->length % 4)
                        no_chunk = 0;
                out_sg = sg_next(out_sg);
        }

        if (no_chunk == 1)
                return sun4i_ss_opti_poll(areq);

        spin_lock_irqsave(&ss->slock, flags);

        for (i = 0; i < op->keylen; i += 4)
                writel(*(op->key + i / 4), ss->base + SS_KEY0 + i);

        if (areq->iv) {
                for (i = 0; i < 4 && i < ivsize / 4; i++) {
                        v = *(u32 *)(areq->iv + i * 4);
                        writel(v, ss->base + SS_IV0 + i * 4);
                }
        }
        writel(mode, ss->base + SS_CTL);

        sg_miter_start(&mi, areq->src, sg_nents(areq->src),
                       SG_MITER_FROM_SG | SG_MITER_ATOMIC);
        sg_miter_start(&mo, areq->dst, sg_nents(areq->dst),
                       SG_MITER_TO_SG | SG_MITER_ATOMIC);
        sg_miter_next(&mi);
        sg_miter_next(&mo);
        if (!mi.addr || !mo.addr) {
                dev_err_ratelimited(ss->dev, "ERROR: sg_miter return null\n");
                err = -EINVAL;
                goto release_ss;
        }
        ileft = areq->cryptlen;
        oleft = areq->cryptlen;
        oi = 0;
        oo = 0;

        while (oleft) {
                if (ileft) {
                        /*
                         * todo is the number of consecutive 4byte word that we
                         * can read from current SG
                         */
                        todo = min3(rx_cnt, ileft / 4, (mi.length - oi) / 4);
                        if (todo && !ob) {
                                writesl(ss->base + SS_RXFIFO, mi.addr + oi,
                                        todo);
                                ileft -= todo * 4;
                                oi += todo * 4;
                        } else {
                                /*
                                 * not enough consecutive bytes, so we need to
                                 * linearize in buf. todo is in bytes
                                 * After that copy, if we have a multiple of 4
                                 * we need to be able to write all buf in one
                                 * pass, so it is why we min() with rx_cnt
                                 */
                                todo = min3(rx_cnt * 4 - ob, ileft,
                                            mi.length - oi);
                                memcpy(buf + ob, mi.addr + oi, todo);
                                ileft -= todo;
                                oi += todo;
                                ob += todo;
                                if (!(ob % 4)) {
                                        writesl(ss->base + SS_RXFIFO, buf,
                                                ob / 4);
                                        ob = 0;
                                }
                        }
                        if (oi == mi.length) {
                                sg_miter_next(&mi);
                                oi = 0;
                        }
                }

                spaces = readl(ss->base + SS_FCSR);
                rx_cnt = SS_RXFIFO_SPACES(spaces);
                tx_cnt = SS_TXFIFO_SPACES(spaces);
                dev_dbg(ss->dev, "%x %u/%u %u/%u cnt=%u %u/%u %u/%u cnt=%u %u\n",
                        mode,
                        oi, mi.length, ileft, areq->cryptlen, rx_cnt,
                        oo, mo.length, oleft, areq->cryptlen, tx_cnt, ob);

                if (!tx_cnt)
                        continue;
                /* todo in 4bytes word */
                todo = min3(tx_cnt, oleft / 4, (mo.length - oo) / 4);
                if (todo) {
                        readsl(ss->base + SS_TXFIFO, mo.addr + oo, todo);
                        oleft -= todo * 4;
                        oo += todo * 4;
                        if (oo == mo.length) {
                                sg_miter_next(&mo);
                                oo = 0;
                        }
                } else {
                        /*
                         * read obl bytes in bufo, we read at maximum for
                         * emptying the device
                         */
                        readsl(ss->base + SS_TXFIFO, bufo, tx_cnt);
                        obl = tx_cnt * 4;
                        obo = 0;
                        do {
                                /*
                                 * how many bytes we can copy ?
                                 * no more than remaining SG size
                                 * no more than remaining buffer
                                 * no need to test against oleft
                                 */
                                todo = min(mo.length - oo, obl - obo);
                                memcpy(mo.addr + oo, bufo + obo, todo);
                                oleft -= todo;
                                obo += todo;
                                oo += todo;
                                if (oo == mo.length) {
                                        sg_miter_next(&mo);
                                        oo = 0;
                                }
                        } while (obo < obl);
                        /* bufo must be fully used here */
                }
        }
        if (areq->iv) {
                for (i = 0; i < 4 && i < ivsize / 4; i++) {
                        v = readl(ss->base + SS_IV0 + i * 4);
                        *(u32 *)(areq->iv + i * 4) = v;
                }
        }

release_ss:
        sg_miter_stop(&mi);
        sg_miter_stop(&mo);
        writel(0, ss->base + SS_CTL);
        spin_unlock_irqrestore(&ss->slock, flags);

        return err;
}

/* CBC AES */
int sun4i_ss_cbc_aes_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_CBC | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cbc_aes_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_CBC | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* ECB AES */
int sun4i_ss_ecb_aes_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_ECB | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_ecb_aes_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_AES | SS_ECB | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* CBC DES */
int sun4i_ss_cbc_des_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_CBC | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cbc_des_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_CBC | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* ECB DES */
int sun4i_ss_ecb_des_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_ECB | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_ecb_des_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_DES | SS_ECB | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* CBC 3DES */
int sun4i_ss_cbc_des3_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_CBC | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cbc_des3_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_CBC | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

/* ECB 3DES */
int sun4i_ss_ecb_des3_encrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_ECB | SS_ENABLED | SS_ENCRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_ecb_des3_decrypt(struct skcipher_request *areq)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(areq);
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_cipher_req_ctx *rctx = skcipher_request_ctx(areq);

        rctx->mode = SS_OP_3DES | SS_ECB | SS_ENABLED | SS_DECRYPTION |
                op->keymode;
        return sun4i_ss_cipher_poll(areq);
}

int sun4i_ss_cipher_init(struct crypto_tfm *tfm)
{
        struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
        struct sun4i_ss_alg_template *algt;

        memset(op, 0, sizeof(struct sun4i_tfm_ctx));

        algt = container_of(tfm->__crt_alg, struct sun4i_ss_alg_template,
                            alg.crypto.base);
        op->ss = algt->ss;

        crypto_skcipher_set_reqsize(__crypto_skcipher_cast(tfm),
                                    sizeof(struct sun4i_cipher_req_ctx));

        return 0;
}

/* check and set the AES key, prepare the mode to be used */
int sun4i_ss_aes_setkey(struct crypto_skcipher *tfm, const u8 *key,
                        unsigned int keylen)
{
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_ss_ctx *ss = op->ss;

        switch (keylen) {
        case 128 / 8:
                op->keymode = SS_AES_128BITS;
                break;
        case 192 / 8:
                op->keymode = SS_AES_192BITS;
                break;
        case 256 / 8:
                op->keymode = SS_AES_256BITS;
                break;
        default:
                dev_err(ss->dev, "ERROR: Invalid keylen %u\n", keylen);
                crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
                return -EINVAL;
        }
        op->keylen = keylen;
        memcpy(op->key, key, keylen);
        return 0;
}

/* check and set the DES key, prepare the mode to be used */
int sun4i_ss_des_setkey(struct crypto_skcipher *tfm, const u8 *key,
                        unsigned int keylen)
{
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        struct sun4i_ss_ctx *ss = op->ss;
        u32 flags;
        u32 tmp[DES_EXPKEY_WORDS];
        int ret;

        if (unlikely(keylen != DES_KEY_SIZE)) {
                dev_err(ss->dev, "Invalid keylen %u\n", keylen);
                crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
                return -EINVAL;
        }

        flags = crypto_skcipher_get_flags(tfm);

        ret = des_ekey(tmp, key);
        if (unlikely(!ret) && (flags & CRYPTO_TFM_REQ_WEAK_KEY)) {
                crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
                dev_dbg(ss->dev, "Weak key %u\n", keylen);
                return -EINVAL;
        }

        op->keylen = keylen;
        memcpy(op->key, key, keylen);
        return 0;
}

/* check and set the 3DES key, prepare the mode to be used */
int sun4i_ss_des3_setkey(struct crypto_skcipher *tfm, const u8 *key,
                         unsigned int keylen)
{
        struct sun4i_tfm_ctx *op = crypto_skcipher_ctx(tfm);
        int err;

        err = des3_verify_key(tfm, key);
        if (unlikely(err))
                return err;

        op->keylen = keylen;
        memcpy(op->key, key, keylen);
        return 0;
}