// SPDX-License-Identifier: GPL-2.0-or-later
 /* Copyright (C) 2004-2006, Advanced Micro Devices, Inc.
  */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/pci_ids.h>
#include <linux/crypto.h>
#include <linux/spinlock.h>
#include <crypto/algapi.h>
#include <crypto/aes.h>
#include <crypto/internal/cipher.h>
#include <crypto/internal/skcipher.h>

#include <linux/io.h>
#include <linux/delay.h>

#include "geode-aes.h"

/* Static structures */

static void __iomem *_iobase;
static DEFINE_SPINLOCK(lock);

/* Write a 128 bit field (either a writable key or IV) */
static inline void
_writefield(u32 offset, const void *value)
{
        int i;

        for (i = 0; i < 4; i++)
                iowrite32(((const u32 *) value)[i], _iobase + offset + (i * 4));
}

/* Read a 128 bit field (either a writable key or IV) */
static inline void
_readfield(u32 offset, void *value)
{
        int i;

        for (i = 0; i < 4; i++)
                ((u32 *) value)[i] = ioread32(_iobase + offset + (i * 4));
}

static int
do_crypt(const void *src, void *dst, u32 len, u32 flags)
{
        u32 status;
        u32 counter = AES_OP_TIMEOUT;

        iowrite32(virt_to_phys((void *)src), _iobase + AES_SOURCEA_REG);
        iowrite32(virt_to_phys(dst), _iobase + AES_DSTA_REG);
        iowrite32(len,  _iobase + AES_LENA_REG);

        /* Start the operation */
        iowrite32(AES_CTRL_START | flags, _iobase + AES_CTRLA_REG);

        do {
                status = ioread32(_iobase + AES_INTR_REG);
                cpu_relax();
        } while (!(status & AES_INTRA_PENDING) && --counter);

        /* Clear the event */
        iowrite32((status & 0xFF) | AES_INTRA_PENDING, _iobase + AES_INTR_REG);
        return counter ? 0 : 1;
}

static void
geode_aes_crypt(const struct geode_aes_tfm_ctx *tctx, const void *src,
                void *dst, u32 len, u8 *iv, int mode, int dir)
{
        u32 flags = 0;
        unsigned long iflags;
        int ret;

        /* If the source and destination is the same, then
         * we need to turn on the coherent flags, otherwise
         * we don't need to worry
         */

        flags |= (AES_CTRL_DCA | AES_CTRL_SCA);

        if (dir == AES_DIR_ENCRYPT)
                flags |= AES_CTRL_ENCRYPT;

        /* Start the critical section */

        spin_lock_irqsave(&lock, iflags);

        if (mode == AES_MODE_CBC) {
                flags |= AES_CTRL_CBC;
                _writefield(AES_WRITEIV0_REG, iv);
        }

        flags |= AES_CTRL_WRKEY;
        _writefield(AES_WRITEKEY0_REG, tctx->key);

        ret = do_crypt(src, dst, len, flags);
        BUG_ON(ret);

        if (mode == AES_MODE_CBC)
                _readfield(AES_WRITEIV0_REG, iv);

        spin_unlock_irqrestore(&lock, iflags);
}

/* CRYPTO-API Functions */

static int geode_setkey_cip(struct crypto_tfm *tfm, const u8 *key,
                unsigned int len)
{
        struct geode_aes_tfm_ctx *tctx = crypto_tfm_ctx(tfm);

        tctx->keylen = len;

        if (len == AES_KEYSIZE_128) {
                memcpy(tctx->key, key, len);
                return 0;
        }

        if (len != AES_KEYSIZE_192 && len != AES_KEYSIZE_256)
                /* not supported at all */
                return -EINVAL;

        /*
         * The requested key size is not supported by HW, do a fallback
         */
        tctx->fallback.cip->base.crt_flags &= ~CRYPTO_TFM_REQ_MASK;
        tctx->fallback.cip->base.crt_flags |=
                (tfm->crt_flags & CRYPTO_TFM_REQ_MASK);

        return crypto_cipher_setkey(tctx->fallback.cip, key, len);
}

static int geode_setkey_skcipher(struct crypto_skcipher *tfm, const u8 *key,
                                 unsigned int len)
{
        struct geode_aes_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);

        tctx->keylen = len;

        if (len == AES_KEYSIZE_128) {
                memcpy(tctx->key, key, len);
                return 0;
        }

        if (len != AES_KEYSIZE_192 && len != AES_KEYSIZE_256)
                /* not supported at all */
                return -EINVAL;

        /*
         * The requested key size is not supported by HW, do a fallback
         */
        crypto_skcipher_clear_flags(tctx->fallback.skcipher,
                                    CRYPTO_TFM_REQ_MASK);
        crypto_skcipher_set_flags(tctx->fallback.skcipher,
                                  crypto_skcipher_get_flags(tfm) &
                                  CRYPTO_TFM_REQ_MASK);
        return crypto_skcipher_setkey(tctx->fallback.skcipher, key, len);
}

static void
geode_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
        const struct geode_aes_tfm_ctx *tctx = crypto_tfm_ctx(tfm);

        if (unlikely(tctx->keylen != AES_KEYSIZE_128)) {
                crypto_cipher_encrypt_one(tctx->fallback.cip, out, in);
                return;
        }

        geode_aes_crypt(tctx, in, out, AES_BLOCK_SIZE, NULL,
                        AES_MODE_ECB, AES_DIR_ENCRYPT);
}


static void
geode_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
        const struct geode_aes_tfm_ctx *tctx = crypto_tfm_ctx(tfm);

        if (unlikely(tctx->keylen != AES_KEYSIZE_128)) {
                crypto_cipher_decrypt_one(tctx->fallback.cip, out, in);
                return;
        }

        geode_aes_crypt(tctx, in, out, AES_BLOCK_SIZE, NULL,
                        AES_MODE_ECB, AES_DIR_DECRYPT);
}

static int fallback_init_cip(struct crypto_tfm *tfm)
{
        const char *name = crypto_tfm_alg_name(tfm);
        struct geode_aes_tfm_ctx *tctx = crypto_tfm_ctx(tfm);

        tctx->fallback.cip = crypto_alloc_cipher(name, 0,
                                                 CRYPTO_ALG_NEED_FALLBACK);

        if (IS_ERR(tctx->fallback.cip)) {
                printk(KERN_ERR "Error allocating fallback algo %s\n", name);
                return PTR_ERR(tctx->fallback.cip);
        }

        return 0;
}

static void fallback_exit_cip(struct crypto_tfm *tfm)
{
        struct geode_aes_tfm_ctx *tctx = crypto_tfm_ctx(tfm);

        crypto_free_cipher(tctx->fallback.cip);
}

static struct crypto_alg geode_alg = {
        .cra_name                       =       "aes",
        .cra_driver_name        =       "geode-aes",
        .cra_priority           =       300,
        .cra_alignmask          =       15,
        .cra_flags                      =       CRYPTO_ALG_TYPE_CIPHER |
                                                        CRYPTO_ALG_NEED_FALLBACK,
        .cra_init                       =       fallback_init_cip,
        .cra_exit                       =       fallback_exit_cip,
        .cra_blocksize          =       AES_BLOCK_SIZE,
        .cra_ctxsize            =       sizeof(struct geode_aes_tfm_ctx),
        .cra_module                     =       THIS_MODULE,
        .cra_u                          =       {
                .cipher =       {
                        .cia_min_keysize        =       AES_MIN_KEY_SIZE,
                        .cia_max_keysize        =       AES_MAX_KEY_SIZE,
                        .cia_setkey                     =       geode_setkey_cip,
                        .cia_encrypt            =       geode_encrypt,
                        .cia_decrypt            =       geode_decrypt
                }
        }
};

static int geode_init_skcipher(struct crypto_skcipher *tfm)
{
        const char *name = crypto_tfm_alg_name(&tfm->base);
        struct geode_aes_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);

        tctx->fallback.skcipher =
                crypto_alloc_skcipher(name, 0, CRYPTO_ALG_NEED_FALLBACK |
                                      CRYPTO_ALG_ASYNC);
        if (IS_ERR(tctx->fallback.skcipher)) {
                printk(KERN_ERR "Error allocating fallback algo %s\n", name);
                return PTR_ERR(tctx->fallback.skcipher);
        }

        crypto_skcipher_set_reqsize(tfm, sizeof(struct skcipher_request) +
                                    crypto_skcipher_reqsize(tctx->fallback.skcipher));
        return 0;
}

static void geode_exit_skcipher(struct crypto_skcipher *tfm)
{
        struct geode_aes_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);

        crypto_free_skcipher(tctx->fallback.skcipher);
}

static int geode_skcipher_crypt(struct skcipher_request *req, int mode, int dir)
{
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
        const struct geode_aes_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
        struct skcipher_walk walk;
        unsigned int nbytes;
        int err;

        if (unlikely(tctx->keylen != AES_KEYSIZE_128)) {
                struct skcipher_request *subreq = skcipher_request_ctx(req);

                *subreq = *req;
                skcipher_request_set_tfm(subreq, tctx->fallback.skcipher);
                if (dir == AES_DIR_DECRYPT)
                        return crypto_skcipher_decrypt(subreq);
                else
                        return crypto_skcipher_encrypt(subreq);
        }

        err = skcipher_walk_virt(&walk, req, false);

        while ((nbytes = walk.nbytes) != 0) {
                geode_aes_crypt(tctx, walk.src.virt.addr, walk.dst.virt.addr,
                                round_down(nbytes, AES_BLOCK_SIZE),
                                walk.iv, mode, dir);
                err = skcipher_walk_done(&walk, nbytes % AES_BLOCK_SIZE);
        }

        return err;
}

static int geode_cbc_encrypt(struct skcipher_request *req)
{
        return geode_skcipher_crypt(req, AES_MODE_CBC, AES_DIR_ENCRYPT);
}

static int geode_cbc_decrypt(struct skcipher_request *req)
{
        return geode_skcipher_crypt(req, AES_MODE_CBC, AES_DIR_DECRYPT);
}

static int geode_ecb_encrypt(struct skcipher_request *req)
{
        return geode_skcipher_crypt(req, AES_MODE_ECB, AES_DIR_ENCRYPT);
}

static int geode_ecb_decrypt(struct skcipher_request *req)
{
        return geode_skcipher_crypt(req, AES_MODE_ECB, AES_DIR_DECRYPT);
}

static struct skcipher_alg geode_skcipher_algs[] = {
        {
                .base.cra_name          = "cbc(aes)",
                .base.cra_driver_name   = "cbc-aes-geode",
                .base.cra_priority      = 400,
                .base.cra_flags         = CRYPTO_ALG_KERN_DRIVER_ONLY |
                                          CRYPTO_ALG_NEED_FALLBACK,
                .base.cra_blocksize     = AES_BLOCK_SIZE,
                .base.cra_ctxsize       = sizeof(struct geode_aes_tfm_ctx),
                .base.cra_alignmask     = 15,
                .base.cra_module        = THIS_MODULE,
                .init                   = geode_init_skcipher,
                .exit                   = geode_exit_skcipher,
                .setkey                 = geode_setkey_skcipher,
                .encrypt                = geode_cbc_encrypt,
                .decrypt                = geode_cbc_decrypt,
                .min_keysize            = AES_MIN_KEY_SIZE,
                .max_keysize            = AES_MAX_KEY_SIZE,
                .ivsize                 = AES_BLOCK_SIZE,
        }, {
                .base.cra_name          = "ecb(aes)",
                .base.cra_driver_name   = "ecb-aes-geode",
                .base.cra_priority      = 400,
                .base.cra_flags         = CRYPTO_ALG_KERN_DRIVER_ONLY |
                                          CRYPTO_ALG_NEED_FALLBACK,
                .base.cra_blocksize     = AES_BLOCK_SIZE,
                .base.cra_ctxsize       = sizeof(struct geode_aes_tfm_ctx),
                .base.cra_alignmask     = 15,
                .base.cra_module        = THIS_MODULE,
                .init                   = geode_init_skcipher,
                .exit                   = geode_exit_skcipher,
                .setkey                 = geode_setkey_skcipher,
                .encrypt                = geode_ecb_encrypt,
                .decrypt                = geode_ecb_decrypt,
                .min_keysize            = AES_MIN_KEY_SIZE,
                .max_keysize            = AES_MAX_KEY_SIZE,
        },
};

static void geode_aes_remove(struct pci_dev *dev)
{
        crypto_unregister_alg(&geode_alg);
        crypto_unregister_skciphers(geode_skcipher_algs,
                                    ARRAY_SIZE(geode_skcipher_algs));

        pci_iounmap(dev, _iobase);
        _iobase = NULL;

        pci_release_regions(dev);
        pci_disable_device(dev);
}


static int geode_aes_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
        int ret;

        ret = pci_enable_device(dev);
        if (ret)
                return ret;

        ret = pci_request_regions(dev, "geode-aes");
        if (ret)
                goto eenable;

        _iobase = pci_iomap(dev, 0, 0);

        if (_iobase == NULL) {
                ret = -ENOMEM;
                goto erequest;
        }

        /* Clear any pending activity */
        iowrite32(AES_INTR_PENDING | AES_INTR_MASK, _iobase + AES_INTR_REG);

        ret = crypto_register_alg(&geode_alg);
        if (ret)
                goto eiomap;

        ret = crypto_register_skciphers(geode_skcipher_algs,
                                        ARRAY_SIZE(geode_skcipher_algs));
        if (ret)
                goto ealg;

        dev_notice(&dev->dev, "GEODE AES engine enabled.\n");
        return 0;

 ealg:
        crypto_unregister_alg(&geode_alg);

 eiomap:
        pci_iounmap(dev, _iobase);

 erequest:
        pci_release_regions(dev);

 eenable:
        pci_disable_device(dev);

        dev_err(&dev->dev, "GEODE AES initialization failed.\n");
        return ret;
}

static struct pci_device_id geode_aes_tbl[] = {
        { PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_LX_AES), },
        { 0, }
};

MODULE_DEVICE_TABLE(pci, geode_aes_tbl);

static struct pci_driver geode_aes_driver = {
        .name = "Geode LX AES",
        .id_table = geode_aes_tbl,
        .probe = geode_aes_probe,
        .remove = geode_aes_remove,
};

module_pci_driver(geode_aes_driver);

MODULE_AUTHOR("Advanced Micro Devices, Inc.");
MODULE_DESCRIPTION("Geode LX Hardware AES driver");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS("CRYPTO_INTERNAL");