/*
 * caam - Freescale FSL CAAM support for Public Key Cryptography
 *
 * Copyright 2016 Freescale Semiconductor, Inc.
 *
 * There is no Shared Descriptor for PKC so that the Job Descriptor must carry
 * all the desired key parameters, input and output pointers.
 */
#include "compat.h"
#include "regs.h"
#include "intern.h"
#include "jr.h"
#include "error.h"
#include "desc_constr.h"
#include "sg_sw_sec4.h"
#include "caampkc.h"

#define DESC_RSA_PUB_LEN        (2 * CAAM_CMD_SZ + sizeof(struct rsa_pub_pdb))
#define DESC_RSA_PRIV_F1_LEN    (2 * CAAM_CMD_SZ + \
                                 sizeof(struct rsa_priv_f1_pdb))

static void rsa_io_unmap(struct device *dev, struct rsa_edesc *edesc,
                         struct akcipher_request *req)
{
        dma_unmap_sg(dev, req->dst, edesc->dst_nents, DMA_FROM_DEVICE);
        dma_unmap_sg(dev, req->src, edesc->src_nents, DMA_TO_DEVICE);

        if (edesc->sec4_sg_bytes)
                dma_unmap_single(dev, edesc->sec4_sg_dma, edesc->sec4_sg_bytes,
                                 DMA_TO_DEVICE);
}

static void rsa_pub_unmap(struct device *dev, struct rsa_edesc *edesc,
                          struct akcipher_request *req)
{
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;
        struct rsa_pub_pdb *pdb = &edesc->pdb.pub;

        dma_unmap_single(dev, pdb->n_dma, key->n_sz, DMA_TO_DEVICE);
        dma_unmap_single(dev, pdb->e_dma, key->e_sz, DMA_TO_DEVICE);
}

static void rsa_priv_f1_unmap(struct device *dev, struct rsa_edesc *edesc,
                              struct akcipher_request *req)
{
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;
        struct rsa_priv_f1_pdb *pdb = &edesc->pdb.priv_f1;

        dma_unmap_single(dev, pdb->n_dma, key->n_sz, DMA_TO_DEVICE);
        dma_unmap_single(dev, pdb->d_dma, key->d_sz, DMA_TO_DEVICE);
}

/* RSA Job Completion handler */
static void rsa_pub_done(struct device *dev, u32 *desc, u32 err, void *context)
{
        struct akcipher_request *req = context;
        struct rsa_edesc *edesc;

        if (err)
                caam_jr_strstatus(dev, err);

        edesc = container_of(desc, struct rsa_edesc, hw_desc[0]);

        rsa_pub_unmap(dev, edesc, req);
        rsa_io_unmap(dev, edesc, req);
        kfree(edesc);

        akcipher_request_complete(req, err);
}

static void rsa_priv_f1_done(struct device *dev, u32 *desc, u32 err,
                             void *context)
{
        struct akcipher_request *req = context;
        struct rsa_edesc *edesc;

        if (err)
                caam_jr_strstatus(dev, err);

        edesc = container_of(desc, struct rsa_edesc, hw_desc[0]);

        rsa_priv_f1_unmap(dev, edesc, req);
        rsa_io_unmap(dev, edesc, req);
        kfree(edesc);

        akcipher_request_complete(req, err);
}

static struct rsa_edesc *rsa_edesc_alloc(struct akcipher_request *req,
                                         size_t desclen)
{
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct device *dev = ctx->dev;
        struct rsa_edesc *edesc;
        gfp_t flags = (req->base.flags & (CRYPTO_TFM_REQ_MAY_BACKLOG |
                       CRYPTO_TFM_REQ_MAY_SLEEP)) ? GFP_KERNEL : GFP_ATOMIC;
        int sgc;
        int sec4_sg_index, sec4_sg_len = 0, sec4_sg_bytes;
        int src_nents, dst_nents;

        src_nents = sg_nents_for_len(req->src, req->src_len);
        dst_nents = sg_nents_for_len(req->dst, req->dst_len);

        if (src_nents > 1)
                sec4_sg_len = src_nents;
        if (dst_nents > 1)
                sec4_sg_len += dst_nents;

        sec4_sg_bytes = sec4_sg_len * sizeof(struct sec4_sg_entry);

        /* allocate space for base edesc, hw desc commands and link tables */
        edesc = kzalloc(sizeof(*edesc) + desclen + sec4_sg_bytes,
                        GFP_DMA | flags);
        if (!edesc)
                return ERR_PTR(-ENOMEM);

        sgc = dma_map_sg(dev, req->src, src_nents, DMA_TO_DEVICE);
        if (unlikely(!sgc)) {
                dev_err(dev, "unable to map source\n");
                goto src_fail;
        }

        sgc = dma_map_sg(dev, req->dst, dst_nents, DMA_FROM_DEVICE);
        if (unlikely(!sgc)) {
                dev_err(dev, "unable to map destination\n");
                goto dst_fail;
        }

        edesc->sec4_sg = (void *)edesc + sizeof(*edesc) + desclen;

        sec4_sg_index = 0;
        if (src_nents > 1) {
                sg_to_sec4_sg_last(req->src, src_nents, edesc->sec4_sg, 0);
                sec4_sg_index += src_nents;
        }
        if (dst_nents > 1)
                sg_to_sec4_sg_last(req->dst, dst_nents,
                                   edesc->sec4_sg + sec4_sg_index, 0);

        /* Save nents for later use in Job Descriptor */
        edesc->src_nents = src_nents;
        edesc->dst_nents = dst_nents;

        if (!sec4_sg_bytes)
                return edesc;

        edesc->sec4_sg_dma = dma_map_single(dev, edesc->sec4_sg,
                                            sec4_sg_bytes, DMA_TO_DEVICE);
        if (dma_mapping_error(dev, edesc->sec4_sg_dma)) {
                dev_err(dev, "unable to map S/G table\n");
                goto sec4_sg_fail;
        }

        edesc->sec4_sg_bytes = sec4_sg_bytes;

        return edesc;

sec4_sg_fail:
        dma_unmap_sg(dev, req->dst, dst_nents, DMA_FROM_DEVICE);
dst_fail:
        dma_unmap_sg(dev, req->src, src_nents, DMA_TO_DEVICE);
src_fail:
        kfree(edesc);
        return ERR_PTR(-ENOMEM);
}

static int set_rsa_pub_pdb(struct akcipher_request *req,
                           struct rsa_edesc *edesc)
{
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;
        struct device *dev = ctx->dev;
        struct rsa_pub_pdb *pdb = &edesc->pdb.pub;
        int sec4_sg_index = 0;

        pdb->n_dma = dma_map_single(dev, key->n, key->n_sz, DMA_TO_DEVICE);
        if (dma_mapping_error(dev, pdb->n_dma)) {
                dev_err(dev, "Unable to map RSA modulus memory\n");
                return -ENOMEM;
        }

        pdb->e_dma = dma_map_single(dev, key->e, key->e_sz, DMA_TO_DEVICE);
        if (dma_mapping_error(dev, pdb->e_dma)) {
                dev_err(dev, "Unable to map RSA public exponent memory\n");
                dma_unmap_single(dev, pdb->n_dma, key->n_sz, DMA_TO_DEVICE);
                return -ENOMEM;
        }

        if (edesc->src_nents > 1) {
                pdb->sgf |= RSA_PDB_SGF_F;
                pdb->f_dma = edesc->sec4_sg_dma;
                sec4_sg_index += edesc->src_nents;
        } else {
                pdb->f_dma = sg_dma_address(req->src);
        }

        if (edesc->dst_nents > 1) {
                pdb->sgf |= RSA_PDB_SGF_G;
                pdb->g_dma = edesc->sec4_sg_dma +
                             sec4_sg_index * sizeof(struct sec4_sg_entry);
        } else {
                pdb->g_dma = sg_dma_address(req->dst);
        }

        pdb->sgf |= (key->e_sz << RSA_PDB_E_SHIFT) | key->n_sz;
        pdb->f_len = req->src_len;

        return 0;
}

static int set_rsa_priv_f1_pdb(struct akcipher_request *req,
                               struct rsa_edesc *edesc)
{
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;
        struct device *dev = ctx->dev;
        struct rsa_priv_f1_pdb *pdb = &edesc->pdb.priv_f1;
        int sec4_sg_index = 0;

        pdb->n_dma = dma_map_single(dev, key->n, key->n_sz, DMA_TO_DEVICE);
        if (dma_mapping_error(dev, pdb->n_dma)) {
                dev_err(dev, "Unable to map modulus memory\n");
                return -ENOMEM;
        }

        pdb->d_dma = dma_map_single(dev, key->d, key->d_sz, DMA_TO_DEVICE);
        if (dma_mapping_error(dev, pdb->d_dma)) {
                dev_err(dev, "Unable to map RSA private exponent memory\n");
                dma_unmap_single(dev, pdb->n_dma, key->n_sz, DMA_TO_DEVICE);
                return -ENOMEM;
        }

        if (edesc->src_nents > 1) {
                pdb->sgf |= RSA_PRIV_PDB_SGF_G;
                pdb->g_dma = edesc->sec4_sg_dma;
                sec4_sg_index += edesc->src_nents;
        } else {
                pdb->g_dma = sg_dma_address(req->src);
        }

        if (edesc->dst_nents > 1) {
                pdb->sgf |= RSA_PRIV_PDB_SGF_F;
                pdb->f_dma = edesc->sec4_sg_dma +
                             sec4_sg_index * sizeof(struct sec4_sg_entry);
        } else {
                pdb->f_dma = sg_dma_address(req->dst);
        }

        pdb->sgf |= (key->d_sz << RSA_PDB_D_SHIFT) | key->n_sz;

        return 0;
}

static int caam_rsa_enc(struct akcipher_request *req)
{
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;
        struct device *jrdev = ctx->dev;
        struct rsa_edesc *edesc;
        int ret;

        if (unlikely(!key->n || !key->e))
                return -EINVAL;

        if (req->dst_len < key->n_sz) {
                req->dst_len = key->n_sz;
                dev_err(jrdev, "Output buffer length less than parameter n\n");
                return -EOVERFLOW;
        }

        /* Allocate extended descriptor */
        edesc = rsa_edesc_alloc(req, DESC_RSA_PUB_LEN);
        if (IS_ERR(edesc))
                return PTR_ERR(edesc);

        /* Set RSA Encrypt Protocol Data Block */
        ret = set_rsa_pub_pdb(req, edesc);
        if (ret)
                goto init_fail;

        /* Initialize Job Descriptor */
        init_rsa_pub_desc(edesc->hw_desc, &edesc->pdb.pub);

        ret = caam_jr_enqueue(jrdev, edesc->hw_desc, rsa_pub_done, req);
        if (!ret)
                return -EINPROGRESS;

        rsa_pub_unmap(jrdev, edesc, req);

init_fail:
        rsa_io_unmap(jrdev, edesc, req);
        kfree(edesc);
        return ret;
}

static int caam_rsa_dec(struct akcipher_request *req)
{
        struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;
        struct device *jrdev = ctx->dev;
        struct rsa_edesc *edesc;
        int ret;

        if (unlikely(!key->n || !key->d))
                return -EINVAL;

        if (req->dst_len < key->n_sz) {
                req->dst_len = key->n_sz;
                dev_err(jrdev, "Output buffer length less than parameter n\n");
                return -EOVERFLOW;
        }

        /* Allocate extended descriptor */
        edesc = rsa_edesc_alloc(req, DESC_RSA_PRIV_F1_LEN);
        if (IS_ERR(edesc))
                return PTR_ERR(edesc);

        /* Set RSA Decrypt Protocol Data Block - Private Key Form #1 */
        ret = set_rsa_priv_f1_pdb(req, edesc);
        if (ret)
                goto init_fail;

        /* Initialize Job Descriptor */
        init_rsa_priv_f1_desc(edesc->hw_desc, &edesc->pdb.priv_f1);

        ret = caam_jr_enqueue(jrdev, edesc->hw_desc, rsa_priv_f1_done, req);
        if (!ret)
                return -EINPROGRESS;

        rsa_priv_f1_unmap(jrdev, edesc, req);

init_fail:
        rsa_io_unmap(jrdev, edesc, req);
        kfree(edesc);
        return ret;
}

static void caam_rsa_free_key(struct caam_rsa_key *key)
{
        kzfree(key->d);
        kfree(key->e);
        kfree(key->n);
        key->d = NULL;
        key->e = NULL;
        key->n = NULL;
        key->d_sz = 0;
        key->e_sz = 0;
        key->n_sz = 0;
}

/**
 * caam_read_raw_data - Read a raw byte stream as a positive integer.
 * The function skips buffer's leading zeros, copies the remained data
 * to a buffer allocated in the GFP_DMA | GFP_KERNEL zone and returns
 * the address of the new buffer.
 *
 * @buf   : The data to read
 * @nbytes: The amount of data to read
 */
static inline u8 *caam_read_raw_data(const u8 *buf, size_t *nbytes)
{
        u8 *val;

        while (!*buf && *nbytes) {
                buf++;
                (*nbytes)--;
        }

        val = kzalloc(*nbytes, GFP_DMA | GFP_KERNEL);
        if (!val)
                return NULL;

        memcpy(val, buf, *nbytes);

        return val;
}

static int caam_rsa_check_key_length(unsigned int len)
{
        if (len > 4096)
                return -EINVAL;
        return 0;
}

static int caam_rsa_set_pub_key(struct crypto_akcipher *tfm, const void *key,
                                unsigned int keylen)
{
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct rsa_key raw_key = {0};
        struct caam_rsa_key *rsa_key = &ctx->key;
        int ret;

        /* Free the old RSA key if any */
        caam_rsa_free_key(rsa_key);

        ret = rsa_parse_pub_key(&raw_key, key, keylen);
        if (ret)
                return ret;

        /* Copy key in DMA zone */
        rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
        if (!rsa_key->e)
                goto err;

        /*
         * Skip leading zeros and copy the positive integer to a buffer
         * allocated in the GFP_DMA | GFP_KERNEL zone. The decryption descriptor
         * expects a positive integer for the RSA modulus and uses its length as
         * decryption output length.
         */
        rsa_key->n = caam_read_raw_data(raw_key.n, &raw_key.n_sz);
        if (!rsa_key->n)
                goto err;

        if (caam_rsa_check_key_length(raw_key.n_sz << 3)) {
                caam_rsa_free_key(rsa_key);
                return -EINVAL;
        }

        rsa_key->e_sz = raw_key.e_sz;
        rsa_key->n_sz = raw_key.n_sz;

        memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);

        return 0;
err:
        caam_rsa_free_key(rsa_key);
        return -ENOMEM;
}

static int caam_rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
                                 unsigned int keylen)
{
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct rsa_key raw_key = {0};
        struct caam_rsa_key *rsa_key = &ctx->key;
        int ret;

        /* Free the old RSA key if any */
        caam_rsa_free_key(rsa_key);

        ret = rsa_parse_priv_key(&raw_key, key, keylen);
        if (ret)
                return ret;

        /* Copy key in DMA zone */
        rsa_key->d = kzalloc(raw_key.d_sz, GFP_DMA | GFP_KERNEL);
        if (!rsa_key->d)
                goto err;

        rsa_key->e = kzalloc(raw_key.e_sz, GFP_DMA | GFP_KERNEL);
        if (!rsa_key->e)
                goto err;

        /*
         * Skip leading zeros and copy the positive integer to a buffer
         * allocated in the GFP_DMA | GFP_KERNEL zone. The decryption descriptor
         * expects a positive integer for the RSA modulus and uses its length as
         * decryption output length.
         */
        rsa_key->n = caam_read_raw_data(raw_key.n, &raw_key.n_sz);
        if (!rsa_key->n)
                goto err;

        if (caam_rsa_check_key_length(raw_key.n_sz << 3)) {
                caam_rsa_free_key(rsa_key);
                return -EINVAL;
        }

        rsa_key->d_sz = raw_key.d_sz;
        rsa_key->e_sz = raw_key.e_sz;
        rsa_key->n_sz = raw_key.n_sz;

        memcpy(rsa_key->d, raw_key.d, raw_key.d_sz);
        memcpy(rsa_key->e, raw_key.e, raw_key.e_sz);

        return 0;

err:
        caam_rsa_free_key(rsa_key);
        return -ENOMEM;
}

static int caam_rsa_max_size(struct crypto_akcipher *tfm)
{
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;

        return (key->n) ? key->n_sz : -EINVAL;
}

/* Per session pkc's driver context creation function */
static int caam_rsa_init_tfm(struct crypto_akcipher *tfm)
{
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);

        ctx->dev = caam_jr_alloc();

        if (IS_ERR(ctx->dev)) {
                dev_err(ctx->dev, "Job Ring Device allocation for transform failed\n");
                return PTR_ERR(ctx->dev);
        }

        return 0;
}

/* Per session pkc's driver context cleanup function */
static void caam_rsa_exit_tfm(struct crypto_akcipher *tfm)
{
        struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
        struct caam_rsa_key *key = &ctx->key;

        caam_rsa_free_key(key);
        caam_jr_free(ctx->dev);
}

static struct akcipher_alg caam_rsa = {
        .encrypt = caam_rsa_enc,
        .decrypt = caam_rsa_dec,
        .sign = caam_rsa_dec,
        .verify = caam_rsa_enc,
        .set_pub_key = caam_rsa_set_pub_key,
        .set_priv_key = caam_rsa_set_priv_key,
        .max_size = caam_rsa_max_size,
        .init = caam_rsa_init_tfm,
        .exit = caam_rsa_exit_tfm,
        .base = {
                .cra_name = "rsa",
                .cra_driver_name = "rsa-caam",
                .cra_priority = 3000,
                .cra_module = THIS_MODULE,
                .cra_ctxsize = sizeof(struct caam_rsa_ctx),
        },
};

/* Public Key Cryptography module initialization handler */
static int __init caam_pkc_init(void)
{
        struct device_node *dev_node;
        struct platform_device *pdev;
        struct device *ctrldev;
        struct caam_drv_private *priv;
        u32 cha_inst, pk_inst;
        int err;

        dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec-v4.0");
        if (!dev_node) {
                dev_node = of_find_compatible_node(NULL, NULL, "fsl,sec4.0");
                if (!dev_node)
                        return -ENODEV;
        }

        pdev = of_find_device_by_node(dev_node);
        if (!pdev) {
                of_node_put(dev_node);
                return -ENODEV;
        }

        ctrldev = &pdev->dev;
        priv = dev_get_drvdata(ctrldev);
        of_node_put(dev_node);

        /*
         * If priv is NULL, it's probably because the caam driver wasn't
         * properly initialized (e.g. RNG4 init failed). Thus, bail out here.
         */
        if (!priv)
                return -ENODEV;

        /* Determine public key hardware accelerator presence. */
        cha_inst = rd_reg32(&priv->ctrl->perfmon.cha_num_ls);
        pk_inst = (cha_inst & CHA_ID_LS_PK_MASK) >> CHA_ID_LS_PK_SHIFT;

        /* Do not register algorithms if PKHA is not present. */
        if (!pk_inst)
                return -ENODEV;

        err = crypto_register_akcipher(&caam_rsa);
        if (err)
                dev_warn(ctrldev, "%s alg registration failed\n",
                         caam_rsa.base.cra_driver_name);
        else
                dev_info(ctrldev, "caam pkc algorithms registered in /proc/crypto\n");

        return err;
}

static void __exit caam_pkc_exit(void)
{
        crypto_unregister_akcipher(&caam_rsa);
}

module_init(caam_pkc_init);
module_exit(caam_pkc_exit);

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("FSL CAAM support for PKC functions of crypto API");
MODULE_AUTHOR("Freescale Semiconductor");