/*
* drivers/misc/tegra-cryptodev.c
*
* crypto dev node for NVIDIA tegra aes hardware
*
* Copyright (c) 2010, NVIDIA Corporation.
*
* 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.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <linux/uaccess.h>
#include <crypto/rng.h>
#include "tegra-cryptodev.h"
#define NBUFS 2
struct tegra_crypto_ctx {
struct crypto_ablkcipher *ecb_tfm;
struct crypto_ablkcipher *cbc_tfm;
struct crypto_rng *rng;
u8 seed[TEGRA_CRYPTO_RNG_SEED_SIZE];
int use_ssk;
};
struct tegra_crypto_completion {
struct completion restart;
int req_err;
};
static int alloc_bufs(unsigned long *buf[NBUFS])
{
int i;
for (i = 0; i < NBUFS; i++) {
buf[i] = (void *)__get_free_page(GFP_KERNEL);
if (!buf[i])
goto err_free_buf;
}
return 0;
err_free_buf:
while (i-- > 0)
free_page((unsigned long)buf[i]);
return -ENOMEM;
}
static void free_bufs(unsigned long *buf[NBUFS])
{
int i;
for (i = 0; i < NBUFS; i++)
free_page((unsigned long)buf[i]);
}
static int tegra_crypto_dev_open(struct inode *inode, struct file *filp)
{
struct tegra_crypto_ctx *ctx;
int ret = 0;
ctx = kzalloc(sizeof(struct tegra_crypto_ctx), GFP_KERNEL);
if (!ctx) {
pr_err("no memory for context\n");
return -ENOMEM;
}
ctx->ecb_tfm = crypto_alloc_ablkcipher("ecb-aes-tegra",
CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC, 0);
if (IS_ERR(ctx->ecb_tfm)) {
pr_err("Failed to load transform for ecb-aes-tegra: %ld\n",
PTR_ERR(ctx->ecb_tfm));
ret = PTR_ERR(ctx->ecb_tfm);
goto fail_ecb;
}
ctx->cbc_tfm = crypto_alloc_ablkcipher("cbc-aes-tegra",
CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC, 0);
if (IS_ERR(ctx->cbc_tfm)) {
pr_err("Failed to load transform for cbc-aes-tegra: %ld\n",
PTR_ERR(ctx->cbc_tfm));
ret = PTR_ERR(ctx->cbc_tfm);
goto fail_cbc;
}
ctx->rng = crypto_alloc_rng("rng-aes-tegra", CRYPTO_ALG_TYPE_RNG, 0);
if (IS_ERR(ctx->rng)) {
pr_err("Failed to load transform for tegra rng: %ld\n",
PTR_ERR(ctx->rng));
ret = PTR_ERR(ctx->rng);
goto fail_rng;
}
filp->private_data = ctx;
return ret;
fail_rng:
crypto_free_ablkcipher(ctx->cbc_tfm);
fail_cbc:
crypto_free_ablkcipher(ctx->ecb_tfm);
fail_ecb:
kfree(ctx);
return ret;
}
static int tegra_crypto_dev_release(struct inode *inode, struct file *filp)
{
struct tegra_crypto_ctx *ctx = filp->private_data;
crypto_free_ablkcipher(ctx->ecb_tfm);
crypto_free_ablkcipher(ctx->cbc_tfm);
crypto_free_rng(ctx->rng);
kfree(ctx);
filp->private_data = NULL;
return 0;
}
static void tegra_crypt_complete(struct crypto_async_request *req, int err)
{
struct tegra_crypto_completion *done = req->data;
if (err != -EINPROGRESS) {
done->req_err = err;
complete(&done->restart);
}
}
static int process_crypt_req(struct tegra_crypto_ctx *ctx, struct tegra_crypt_req *crypt_req)
{
struct crypto_ablkcipher *tfm;
struct ablkcipher_request *req = NULL;
struct scatterlist in_sg;
struct scatterlist out_sg;
unsigned long *xbuf[NBUFS];
int ret = 0, size = 0;
unsigned long total = 0;
struct tegra_crypto_completion tcrypt_complete;
const u8 *key = NULL;
if (crypt_req->op & TEGRA_CRYPTO_ECB) {
req = ablkcipher_request_alloc(ctx->ecb_tfm, GFP_KERNEL);
tfm = ctx->ecb_tfm;
} else {
req = ablkcipher_request_alloc(ctx->cbc_tfm, GFP_KERNEL);
tfm = ctx->cbc_tfm;
}
if (!req) {
pr_err("%s: Failed to allocate request\n", __func__);
return -ENOMEM;
}
if ((crypt_req->keylen < 0) || (crypt_req->keylen > AES_MAX_KEY_SIZE))
return -EINVAL;
crypto_ablkcipher_clear_flags(tfm, ~0);
if (!ctx->use_ssk)
key = crypt_req->key;
ret = crypto_ablkcipher_setkey(tfm, key, crypt_req->keylen);
if (ret < 0) {
pr_err("setkey failed");
goto process_req_out;
}
ret = alloc_bufs(xbuf);
if (ret < 0) {
pr_err("alloc_bufs failed");
goto process_req_out;
}
init_completion(&tcrypt_complete.restart);
ablkcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG,
tegra_crypt_complete, &tcrypt_complete);
total = crypt_req->plaintext_sz;
while (total > 0) {
size = min(total, PAGE_SIZE);
ret = copy_from_user((void *)xbuf[0],
(void __user *)crypt_req->plaintext, size);
if (ret < 0) {
pr_debug("%s: copy_from_user failed (%d)\n", __func__, ret);
goto process_req_buf_out;
}
sg_init_one(&in_sg, xbuf[0], size);
sg_init_one(&out_sg, xbuf[1], size);
ablkcipher_request_set_crypt(req, &in_sg,
&out_sg, size, crypt_req->iv);
INIT_COMPLETION(tcrypt_complete.restart);
tcrypt_complete.req_err = 0;
ret = crypt_req->encrypt ?
crypto_ablkcipher_encrypt(req) :
crypto_ablkcipher_decrypt(req);
if ((ret == -EINPROGRESS) || (ret == -EBUSY)) {
/* crypto driver is asynchronous */
ret = wait_for_completion_interruptible(&tcrypt_complete.restart);
if (ret < 0)
goto process_req_buf_out;
if (tcrypt_complete.req_err < 0) {
ret = tcrypt_complete.req_err;
goto process_req_buf_out;
}
} else if (ret < 0) {
pr_debug("%scrypt failed (%d)\n",
crypt_req->encrypt ? "en" : "de", ret);
goto process_req_buf_out;
}
ret = copy_to_user((void __user *)crypt_req->result,
(const void *)xbuf[1], size);
if (ret < 0)
goto process_req_buf_out;
total -= size;
crypt_req->result += size;
crypt_req->plaintext += size;
}
process_req_buf_out:
free_bufs(xbuf);
process_req_out:
ablkcipher_request_free(req);
return ret;
}
static long tegra_crypto_dev_ioctl(struct file *filp,
unsigned int ioctl_num, unsigned long arg)
{
struct tegra_crypto_ctx *ctx = filp->private_data;
struct tegra_crypt_req crypt_req;
struct tegra_rng_req rng_req;
char *rng;
int ret = 0;
switch (ioctl_num) {
case TEGRA_CRYPTO_IOCTL_NEED_SSK:
ctx->use_ssk = (int)arg;
break;
case TEGRA_CRYPTO_IOCTL_PROCESS_REQ:
ret = copy_from_user(&crypt_req, (void __user *)arg, sizeof(crypt_req));
if (ret < 0) {
pr_err("%s: copy_from_user fail(%d)\n", __func__, ret);
break;
}
ret = process_crypt_req(ctx, &crypt_req);
break;
case TEGRA_CRYPTO_IOCTL_SET_SEED:
if (copy_from_user(&rng_req, (void __user *)arg, sizeof(rng_req)))
return -EFAULT;
memcpy(ctx->seed, rng_req.seed, TEGRA_CRYPTO_RNG_SEED_SIZE);
ret = crypto_rng_reset(ctx->rng, ctx->seed,
crypto_rng_seedsize(ctx->rng));
break;
case TEGRA_CRYPTO_IOCTL_GET_RANDOM:
if (copy_from_user(&rng_req, (void __user *)arg, sizeof(rng_req)))
return -EFAULT;
rng = kzalloc(rng_req.nbytes, GFP_KERNEL);
if (!rng) {
pr_err("mem alloc for rng fail");
ret = -ENODATA;
goto rng_out;
}
ret = crypto_rng_get_bytes(ctx->rng, rng,
rng_req.nbytes);
if (ret != rng_req.nbytes) {
pr_err("rng failed");
ret = -ENODATA;
goto rng_out;
}
ret = copy_to_user((void __user *)rng_req.rdata,
(const void *)rng, rng_req.nbytes);
ret = (ret < 0) ? -ENODATA : 0;
rng_out:
if (rng)
kfree(rng);
break;
default:
pr_debug("invalid ioctl code(%d)", ioctl_num);
ret = -EINVAL;
}
return ret;
}
struct file_operations tegra_crypto_fops = {
.owner = THIS_MODULE,
.open = tegra_crypto_dev_open,
.release = tegra_crypto_dev_release,
.unlocked_ioctl = tegra_crypto_dev_ioctl,
};
struct miscdevice tegra_crypto_device = {
.minor = MISC_DYNAMIC_MINOR,
.name = "tegra-crypto",
.fops = &tegra_crypto_fops,
};
static int __init tegra_crypto_dev_init(void)
{
return misc_register(&tegra_crypto_device);
}
late_initcall(tegra_crypto_dev_init);
MODULE_DESCRIPTION("Tegra AES hw device node.");
MODULE_AUTHOR("NVIDIA Corporation");
MODULE_LICENSE("GPLv2");
