/*
 * 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)--;
	}
	if (!*nbytes)
		return NULL;

	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 = {NULL};
	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 = {NULL};
	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)) {
		pr_err("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");