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geode-aes.c

 /* Copyright (C) 2004-2006, Advanced Micro Devices, Inc.
 *
 * 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 <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 <asm/io.h>
#include <asm/delay.h>

#include "geode-aes.h"

/* Register definitions */

#define AES_CTRLA_REG  0x0000

#define AES_CTRL_START     0x01
#define AES_CTRL_DECRYPT   0x00
#define AES_CTRL_ENCRYPT   0x02
#define AES_CTRL_WRKEY     0x04
#define AES_CTRL_DCA       0x08
#define AES_CTRL_SCA       0x10
#define AES_CTRL_CBC       0x20

#define AES_INTR_REG  0x0008

#define AES_INTRA_PENDING (1 << 16)
#define AES_INTRB_PENDING (1 << 17)

#define AES_INTR_PENDING  (AES_INTRA_PENDING | AES_INTRB_PENDING)
#define AES_INTR_MASK     0x07

#define AES_SOURCEA_REG   0x0010
#define AES_DSTA_REG      0x0014
#define AES_LENA_REG      0x0018
#define AES_WRITEKEY0_REG 0x0030
#define AES_WRITEIV0_REG  0x0040

/*  A very large counter that is used to gracefully bail out of an
 *  operation in case of trouble
 */

#define AES_OP_TIMEOUT    0x50000

/* Static structures */

static void __iomem * _iobase;
static spinlock_t lock;

/* Write a 128 bit field (either a writable key or IV) */
static inline void
_writefield(u32 offset, void *value)
{
      int i;
      for(i = 0; i < 4; i++)
            iowrite32(((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(void *src, void *dst, int len, u32 flags)
{
      u32 status;
      u32 counter = AES_OP_TIMEOUT;

      iowrite32(virt_to_phys(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);
      while(!(status & AES_INTRA_PENDING) && --counter);

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

static unsigned int
geode_aes_crypt(struct geode_aes_op *op)
{
      u32 flags = 0;
      unsigned long iflags;

      if (op->len == 0)
            return 0;

      /* 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 (op->dir == AES_DIR_ENCRYPT)
            flags |= AES_CTRL_ENCRYPT;

      /* Start the critical section */

      spin_lock_irqsave(&lock, iflags);

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

      if (!(op->flags & AES_FLAGS_HIDDENKEY)) {
            flags |= AES_CTRL_WRKEY;
            _writefield(AES_WRITEKEY0_REG, op->key);
      }

      do_crypt(op->src, op->dst, op->len, flags);

      if (op->mode == AES_MODE_CBC)
            _readfield(AES_WRITEIV0_REG, op->iv);

      spin_unlock_irqrestore(&lock, iflags);

      return op->len;
}

/* CRYPTO-API Functions */

static int
geode_setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int len)
{
      struct geode_aes_op *op = crypto_tfm_ctx(tfm);

      if (len != AES_KEY_LENGTH) {
            tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
            return -EINVAL;
      }

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

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

      if ((out == NULL) || (in == NULL))
            return;

      op->src = (void *) in;
      op->dst = (void *) out;
      op->mode = AES_MODE_ECB;
      op->flags = 0;
      op->len = AES_MIN_BLOCK_SIZE;
      op->dir = AES_DIR_ENCRYPT;

      geode_aes_crypt(op);
}


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

      if ((out == NULL) || (in == NULL))
            return;

      op->src = (void *) in;
      op->dst = (void *) out;
      op->mode = AES_MODE_ECB;
      op->flags = 0;
      op->len = AES_MIN_BLOCK_SIZE;
      op->dir = AES_DIR_DECRYPT;

      geode_aes_crypt(op);
}


static struct crypto_alg geode_alg = {
      .cra_name               =       "aes",
      .cra_driver_name  =       "geode-aes-128",
      .cra_priority           =       300,
      .cra_alignmask          =       15,
      .cra_flags        =     CRYPTO_ALG_TYPE_CIPHER,
      .cra_blocksize          =     AES_MIN_BLOCK_SIZE,
      .cra_ctxsize            =     sizeof(struct geode_aes_op),
      .cra_module       =     THIS_MODULE,
      .cra_list         =     LIST_HEAD_INIT(geode_alg.cra_list),
      .cra_u                  =     {
            .cipher = {
                  .cia_min_keysize  =  AES_KEY_LENGTH,
                  .cia_max_keysize  =  AES_KEY_LENGTH,
                  .cia_setkey       =  geode_setkey,
                  .cia_encrypt            =  geode_encrypt,
                  .cia_decrypt            =  geode_decrypt
            }
      }
};

static int
geode_cbc_decrypt(struct blkcipher_desc *desc,
              struct scatterlist *dst, struct scatterlist *src,
              unsigned int nbytes)
{
      struct geode_aes_op *op = crypto_blkcipher_ctx(desc->tfm);
      struct blkcipher_walk walk;
      int err, ret;

      blkcipher_walk_init(&walk, dst, src, nbytes);
      err = blkcipher_walk_virt(desc, &walk);

      while((nbytes = walk.nbytes)) {
            op->src = walk.src.virt.addr,
            op->dst = walk.dst.virt.addr;
            op->mode = AES_MODE_CBC;
            op->len = nbytes - (nbytes % AES_MIN_BLOCK_SIZE);
            op->dir = AES_DIR_DECRYPT;

            memcpy(op->iv, walk.iv, AES_IV_LENGTH);

            ret = geode_aes_crypt(op);

            memcpy(walk.iv, op->iv, AES_IV_LENGTH);
            nbytes -= ret;

            err = blkcipher_walk_done(desc, &walk, nbytes);
      }

      return err;
}

static int
geode_cbc_encrypt(struct blkcipher_desc *desc,
              struct scatterlist *dst, struct scatterlist *src,
              unsigned int nbytes)
{
      struct geode_aes_op *op = crypto_blkcipher_ctx(desc->tfm);
      struct blkcipher_walk walk;
      int err, ret;

      blkcipher_walk_init(&walk, dst, src, nbytes);
      err = blkcipher_walk_virt(desc, &walk);

      while((nbytes = walk.nbytes)) {
            op->src = walk.src.virt.addr,
            op->dst = walk.dst.virt.addr;
            op->mode = AES_MODE_CBC;
            op->len = nbytes - (nbytes % AES_MIN_BLOCK_SIZE);
            op->dir = AES_DIR_ENCRYPT;

            memcpy(op->iv, walk.iv, AES_IV_LENGTH);

            ret = geode_aes_crypt(op);
            nbytes -= ret;
            err = blkcipher_walk_done(desc, &walk, nbytes);
      }

      return err;
}

static struct crypto_alg geode_cbc_alg = {
      .cra_name         =     "cbc(aes)",
      .cra_driver_name  =     "cbc-aes-geode-128",
      .cra_priority           =     400,
      .cra_flags        =     CRYPTO_ALG_TYPE_BLKCIPHER,
      .cra_blocksize          =     AES_MIN_BLOCK_SIZE,
      .cra_ctxsize            =     sizeof(struct geode_aes_op),
      .cra_alignmask          =     15,
      .cra_type         =     &crypto_blkcipher_type,
      .cra_module       =     THIS_MODULE,
      .cra_list         =     LIST_HEAD_INIT(geode_cbc_alg.cra_list),
      .cra_u                  =     {
            .blkcipher = {
                  .min_keysize            =     AES_KEY_LENGTH,
                  .max_keysize            =     AES_KEY_LENGTH,
                  .setkey                 =     geode_setkey,
                  .encrypt          =     geode_cbc_encrypt,
                  .decrypt          =     geode_cbc_decrypt,
                  .ivsize                 =     AES_IV_LENGTH,
            }
      }
};

static int
geode_ecb_decrypt(struct blkcipher_desc *desc,
              struct scatterlist *dst, struct scatterlist *src,
              unsigned int nbytes)
{
      struct geode_aes_op *op = crypto_blkcipher_ctx(desc->tfm);
      struct blkcipher_walk walk;
      int err, ret;

      blkcipher_walk_init(&walk, dst, src, nbytes);
      err = blkcipher_walk_virt(desc, &walk);

      while((nbytes = walk.nbytes)) {
            op->src = walk.src.virt.addr,
            op->dst = walk.dst.virt.addr;
            op->mode = AES_MODE_ECB;
            op->len = nbytes - (nbytes % AES_MIN_BLOCK_SIZE);
            op->dir = AES_DIR_DECRYPT;

            ret = geode_aes_crypt(op);
            nbytes -= ret;
            err = blkcipher_walk_done(desc, &walk, nbytes);
      }

      return err;
}

static int
geode_ecb_encrypt(struct blkcipher_desc *desc,
              struct scatterlist *dst, struct scatterlist *src,
              unsigned int nbytes)
{
      struct geode_aes_op *op = crypto_blkcipher_ctx(desc->tfm);
      struct blkcipher_walk walk;
      int err, ret;

      blkcipher_walk_init(&walk, dst, src, nbytes);
      err = blkcipher_walk_virt(desc, &walk);

      while((nbytes = walk.nbytes)) {
            op->src = walk.src.virt.addr,
            op->dst = walk.dst.virt.addr;
            op->mode = AES_MODE_ECB;
            op->len = nbytes - (nbytes % AES_MIN_BLOCK_SIZE);
            op->dir = AES_DIR_ENCRYPT;

            ret = geode_aes_crypt(op);
            nbytes -= ret;
            ret =  blkcipher_walk_done(desc, &walk, nbytes);
      }

      return err;
}

static struct crypto_alg geode_ecb_alg = {
      .cra_name         =     "ecb(aes)",
      .cra_driver_name  =     "ecb-aes-geode-128",
      .cra_priority           =     400,
      .cra_flags        =     CRYPTO_ALG_TYPE_BLKCIPHER,
      .cra_blocksize          =     AES_MIN_BLOCK_SIZE,
      .cra_ctxsize            =     sizeof(struct geode_aes_op),
      .cra_alignmask          =     15,
      .cra_type         =     &crypto_blkcipher_type,
      .cra_module       =     THIS_MODULE,
      .cra_list         =     LIST_HEAD_INIT(geode_ecb_alg.cra_list),
      .cra_u                  =     {
            .blkcipher = {
                  .min_keysize            =     AES_KEY_LENGTH,
                  .max_keysize            =     AES_KEY_LENGTH,
                  .setkey                 =     geode_setkey,
                  .encrypt          =     geode_ecb_encrypt,
                  .decrypt          =     geode_ecb_decrypt,
            }
      }
};

static void
geode_aes_remove(struct pci_dev *dev)
{
      crypto_unregister_alg(&geode_alg);
      crypto_unregister_alg(&geode_ecb_alg);
      crypto_unregister_alg(&geode_cbc_alg);

      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;

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

      if ((ret = pci_request_regions(dev, "geode-aes-128")))
            goto eenable;

      _iobase = pci_iomap(dev, 0, 0);

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

      spin_lock_init(&lock);

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

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

      if ((ret = crypto_register_alg(&geode_ecb_alg)))
            goto ealg;

      if ((ret = crypto_register_alg(&geode_cbc_alg)))
            goto eecb;

      printk(KERN_NOTICE "geode-aes: GEODE AES engine enabled.\n");
      return 0;

 eecb:
      crypto_unregister_alg(&geode_ecb_alg);

 ealg:
      crypto_unregister_alg(&geode_alg);

 eiomap:
      pci_iounmap(dev, _iobase);

 erequest:
      pci_release_regions(dev);

 eenable:
      pci_disable_device(dev);

      printk(KERN_ERR "geode-aes:  GEODE AES initialization failed.\n");
      return ret;
}

static struct pci_device_id geode_aes_tbl[] = {
      { PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_LX_AES, PCI_ANY_ID, PCI_ANY_ID} ,
      { 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 = __devexit_p(geode_aes_remove)
};

static int __init
geode_aes_init(void)
{
      return pci_register_driver(&geode_aes_driver);
}

static void __exit
geode_aes_exit(void)
{
      pci_unregister_driver(&geode_aes_driver);
}

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

module_init(geode_aes_init);
module_exit(geode_aes_exit);

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