path: root/drivers/crypto/amcc/crypto4xx_core.c

/**
 * AMCC SoC PPC4xx Crypto Driver
 *
 * Copyright (c) 2008 Applied Micro Circuits Corporation.
 * All rights reserved. James Hsiao <jhsiao@amcc.com>
 *
 * 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.
 *
 * This file implements AMCC crypto offload Linux device driver for use with
 * Linux CryptoAPI.
 */

#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/spinlock_types.h>
#include <linux/random.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/of_platform.h>
#include <asm/dcr.h>
#include <asm/dcr-regs.h>
#include <asm/cacheflush.h>
#include <crypto/aes.h>
#include <crypto/sha.h>
#include "crypto4xx_reg_def.h"
#include "crypto4xx_core.h"
#include "crypto4xx_sa.h"

#define PPC4XX_SEC_VERSION_STR			"0.5"

/**
 * PPC4xx Crypto Engine Initialization Routine
 */
static void crypto4xx_hw_init(struct crypto4xx_device *dev)
{
	union ce_ring_size ring_size;
	union ce_ring_contol ring_ctrl;
	union ce_part_ring_size part_ring_size;
	union ce_io_threshold io_threshold;
	u32 rand_num;
	union ce_pe_dma_cfg pe_dma_cfg;

	writel(PPC4XX_BYTE_ORDER, dev->ce_base + CRYPTO4XX_BYTE_ORDER_CFG);
	/* setup pe dma, include reset sg, pdr and pe, then release reset */
	pe_dma_cfg.w = 0;
	pe_dma_cfg.bf.bo_sgpd_en = 1;
	pe_dma_cfg.bf.bo_data_en = 0;
	pe_dma_cfg.bf.bo_sa_en = 1;
	pe_dma_cfg.bf.bo_pd_en = 1;
	pe_dma_cfg.bf.dynamic_sa_en = 1;
	pe_dma_cfg.bf.reset_sg = 1;
	pe_dma_cfg.bf.reset_pdr = 1;
	pe_dma_cfg.bf.reset_pe = 1;
	writel(pe_dma_cfg.w, dev->ce_base + CRYPTO4XX_PE_DMA_CFG);
	/* un reset pe,sg and pdr */
	pe_dma_cfg.bf.pe_mode = 0;
	pe_dma_cfg.bf.reset_sg = 0;
	pe_dma_cfg.bf.reset_pdr = 0;
	pe_dma_cfg.bf.reset_pe = 0;
	pe_dma_cfg.bf.bo_td_en = 0;
	writel(pe_dma_cfg.w, dev->ce_base + CRYPTO4XX_PE_DMA_CFG);
	writel(dev->pdr_pa, dev->ce_base + CRYPTO4XX_PDR_BASE);
	writel(dev->pdr_pa, dev->ce_base + CRYPTO4XX_RDR_BASE);
	writel(PPC4XX_PRNG_CTRL_AUTO_EN, dev->ce_base + CRYPTO4XX_PRNG_CTRL);
	get_random_bytes(&rand_num, sizeof(rand_num));
	writel(rand_num, dev->ce_base + CRYPTO4XX_PRNG_SEED_L);
	get_random_bytes(&rand_num, sizeof(rand_num));
	writel(rand_num, dev->ce_base + CRYPTO4XX_PRNG_SEED_H);
	ring_size.w = 0;
	ring_size.bf.ring_offset = PPC4XX_PD_SIZE;
	ring_size.bf.ring_size   = PPC4XX_NUM_PD;
	writel(ring_size.w, dev->ce_base + CRYPTO4XX_RING_SIZE);
	ring_ctrl.w = 0;
	writel(ring_ctrl.w, dev->ce_base + CRYPTO4XX_RING_CTRL);
	writel(PPC4XX_DC_3DES_EN, dev->ce_base + CRYPTO4XX_DEVICE_CTRL);
	writel(dev->gdr_pa, dev->ce_base + CRYPTO4XX_GATH_RING_BASE);
	writel(dev->sdr_pa, dev->ce_base + CRYPTO4XX_SCAT_RING_BASE);
	part_ring_size.w = 0;
	part_ring_size.bf.sdr_size = PPC4XX_SDR_SIZE;
	part_ring_size.bf.gdr_size = PPC4XX_GDR_SIZE;
	writel(part_ring_size.w, dev->ce_base + CRYPTO4XX_PART_RING_SIZE);
	writel(PPC4XX_SD_BUFFER_SIZE, dev->ce_base + CRYPTO4XX_PART_RING_CFG);
	io_threshold.w = 0;
	io_threshold.bf.output_threshold = PPC4XX_OUTPUT_THRESHOLD;
	io_threshold.bf.input_threshold  = PPC4XX_INPUT_THRESHOLD;
	writel(io_threshold.w, dev->ce_base + CRYPTO4XX_IO_THRESHOLD);
	writel(0, dev->ce_base + CRYPTO4XX_PDR_BASE_UADDR);
	writel(0, dev->ce_base + CRYPTO4XX_RDR_BASE_UADDR);
	writel(0, dev->ce_base + CRYPTO4XX_PKT_SRC_UADDR);
	writel(0, dev->ce_base + CRYPTO4XX_PKT_DEST_UADDR);
	writel(0, dev->ce_base + CRYPTO4XX_SA_UADDR);
	writel(0, dev->ce_base + CRYPTO4XX_GATH_RING_BASE_UADDR);
	writel(0, dev->ce_base + CRYPTO4XX_SCAT_RING_BASE_UADDR);
	/* un reset pe,sg and pdr */
	pe_dma_cfg.bf.pe_mode = 1;
	pe_dma_cfg.bf.reset_sg = 0;
	pe_dma_cfg.bf.reset_pdr = 0;
	pe_dma_cfg.bf.reset_pe = 0;
	pe_dma_cfg.bf.bo_td_en = 0;
	writel(pe_dma_cfg.w, dev->ce_base + CRYPTO4XX_PE_DMA_CFG);
	/*clear all pending interrupt*/
	writel(PPC4XX_INTERRUPT_CLR, dev->ce_base + CRYPTO4XX_INT_CLR);
	writel(PPC4XX_INT_DESCR_CNT, dev->ce_base + CRYPTO4XX_INT_DESCR_CNT);
	writel(PPC4XX_INT_DESCR_CNT, dev->ce_base + CRYPTO4XX_INT_DESCR_CNT);
	writel(PPC4XX_INT_CFG, dev->ce_base + CRYPTO4XX_INT_CFG);
	writel(PPC4XX_PD_DONE_INT, dev->ce_base + CRYPTO4XX_INT_EN);
}

int crypto4xx_alloc_sa(struct crypto4xx_ctx *ctx, u32 size)
{
	ctx->sa_in = dma_alloc_coherent(ctx->dev->core_dev->device, size * 4,
					&ctx->sa_in_dma_addr, GFP_ATOMIC);
	if (ctx->sa_in == NULL)
		return -ENOMEM;

	ctx->sa_out = dma_alloc_coherent(ctx->dev->core_dev->device, size * 4,
					 &ctx->sa_out_dma_addr, GFP_ATOMIC);
	if (ctx->sa_out == NULL) {
		dma_free_coherent(ctx->dev->core_dev->device,
				  ctx->sa_len * 4,
				  ctx->sa_in, ctx->sa_in_dma_addr);
		return -ENOMEM;
	}

	memset(ctx->sa_in, 0, size * 4);
	memset(ctx->sa_out, 0, size * 4);
	ctx->sa_len = size;

	return 0;
}

void crypto4xx_free_sa(struct crypto4xx_ctx *ctx)
{
	if (ctx->sa_in != NULL)
		dma_free_coherent(ctx->dev->core_dev->device, ctx->sa_len * 4,
				  ctx->sa_in, ctx->sa_in_dma_addr);
	if (ctx->sa_out != NULL)
		dma_free_coherent(ctx->dev->core_dev->device, ctx->sa_len * 4,
				  ctx->sa_out, ctx->sa_out_dma_addr);

	ctx->sa_in_dma_addr = 0;
	ctx->sa_out_dma_addr = 0;
	ctx->sa_len = 0;
}

u32 crypto4xx_alloc_state_record(struct crypto4xx_ctx *ctx)
{
	ctx->state_record = dma_alloc_coherent(ctx->dev->core_dev->device,
				sizeof(struct sa_state_record),
				&ctx->state_record_dma_addr, GFP_ATOMIC);
	if (!ctx->state_record_dma_addr)
		return -ENOMEM;
	memset(ctx->state_record, 0, sizeof(struct sa_state_record));

	return 0;
}

void crypto4xx_free_state_record(struct crypto4xx_ctx *ctx)
{
	if (ctx->state_record != NULL)
		dma_free_coherent(ctx->dev->core_dev->device,
				  sizeof(struct sa_state_record),
				  ctx->state_record,
				  ctx->state_record_dma_addr);
	ctx->state_record_dma_addr = 0;
}

/**
 * alloc memory for the gather ring
 * no need to alloc buf for the ring
 * gdr_tail, gdr_head and gdr_count are initialized by this function
 */
static u32 crypto4xx_build_pdr(struct crypto4xx_device *dev)
{
	int i;
	struct pd_uinfo *pd_uinfo;
	dev->pdr = dma_alloc_coherent(dev->core_dev->device,
				      sizeof(struct ce_pd) * PPC4XX_NUM_PD,
				      &dev->pdr_pa, GFP_ATOMIC);
	if (!dev->pdr)
		return -ENOMEM;

	dev->pdr_uinfo = kzalloc(sizeof(struct pd_uinfo) * PPC4XX_NUM_PD,
				GFP_KERNEL);
	if (!dev->pdr_uinfo) {
		dma_free_coherent(dev->core_dev->device,
				  sizeof(struct ce_pd) * PPC4XX_NUM_PD,
				  dev->pdr,
				  dev->pdr_pa);
		return -ENOMEM;
	}
	memset(dev->pdr, 0,  sizeof(struct ce_pd) * PPC4XX_NUM_PD);
	dev->shadow_sa_pool = dma_alloc_coherent(dev->core_dev->device,
				   256 * PPC4XX_NUM_PD,
				   &dev->shadow_sa_pool_pa,
				   GFP_ATOMIC);
	if (!dev->shadow_sa_pool)
		return -ENOMEM;

	dev->shadow_sr_pool = dma_alloc_coherent(dev->core_dev->device,
			 sizeof(struct sa_state_record) * PPC4XX_NUM_PD,
			 &dev->shadow_sr_pool_pa, GFP_ATOMIC);
	if (!dev->shadow_sr_pool)
		return -ENOMEM;
	for (i = 0; i < PPC4XX_NUM_PD; i++) {
		pd_uinfo = (struct pd_uinfo *) (dev->pdr_uinfo +
						sizeof(struct pd_uinfo) * i);

		/* alloc 256 bytes which is enough for any kind of dynamic sa */
		pd_uinfo->sa_va = dev->shadow_sa_pool + 256 * i;
		pd_uinfo->sa_pa = dev->shadow_sa_pool_pa + 256 * i;

		/* alloc state record */
		pd_uinfo->sr_va = dev->shadow_sr_pool +
		    sizeof(struct sa_state_record) * i;
		pd_uinfo->sr_pa = dev->shadow_sr_pool_pa +
		    sizeof(struct sa_state_record) * i;
	}

	return 0;
}

static void crypto4xx_destroy_pdr(struct crypto4xx_device *dev)
{
	if (dev->pdr != NULL)
		dma_free_coherent(dev->core_dev->device,
				  sizeof(struct ce_pd) * PPC4XX_NUM_PD,
				  dev->pdr, dev->pdr_pa);
	if (dev->shadow_sa_pool)
		dma_free_coherent(dev->core_dev->device, 256 * PPC4XX_NUM_PD,
				  dev->shadow_sa_pool, dev->shadow_sa_pool_pa);
	if (dev->shadow_sr_pool)
		dma_free_coherent(dev->core_dev->device,
			sizeof(struct sa_state_record) * PPC4XX_NUM_PD,
			dev->shadow_sr_pool, dev->shadow_sr_pool_pa);

	kfree(dev->pdr_uinfo);
}

static u32 crypto4xx_get_pd_from_pdr_nolock(struct crypto4xx_device *dev)
{
	u32 retval;
	u32 tmp;

	retval = dev->pdr_head;
	tmp = (dev->pdr_head + 1) % PPC4XX_NUM_PD;

	if (tmp == dev->pdr_tail)
		return ERING_WAS_FULL;

	dev->pdr_head = tmp;

	return retval;
}

static u32 crypto4xx_put_pd_to_pdr(struct crypto4xx_device *dev, u32 idx)
{
	struct pd_uinfo *pd_uinfo;
	unsigned long flags;

	pd_uinfo = (struct pd_uinfo *)(dev->pdr_uinfo +
				       sizeof(struct pd_uinfo) * idx);
	spin_lock_irqsave(&dev->core_dev->lock, flags);
	if (dev->pdr_tail != PPC4XX_LAST_PD)
		dev->pdr_tail++;
	else
		dev->pdr_tail = 0;
	pd_uinfo->state = PD_ENTRY_FREE;
	spin_unlock_irqrestore(&dev->core_dev->lock, flags);

	return 0;
}

static struct ce_pd *crypto4xx_get_pdp(struct crypto4xx_device *dev,
				       dma_addr_t *pd_dma, u32 idx)
{
	*pd_dma = dev->pdr_pa + sizeof(struct ce_pd) * idx;

	return dev->pdr + sizeof(struct ce_pd) * idx;
}

/**
 * alloc memory for the gather ring
 * no need to alloc buf for the ring
 * gdr_tail, gdr_head and gdr_count are initialized by this function
 */
static u32 crypto4xx_build_gdr(struct crypto4xx_device *dev)
{
	dev->gdr = dma_alloc_coherent(dev->core_dev->device,
				      sizeof(struct ce_gd) * PPC4XX_NUM_GD,
				      &dev->gdr_pa, GFP_ATOMIC);
	if (!dev->gdr)
		return -ENOMEM;

	memset(dev->gdr, 0, sizeof(struct ce_gd) * PPC4XX_NUM_GD);

	return 0;
}

static inline void crypto4xx_destroy_gdr(struct crypto4xx_device *dev)
{
	dma_free_coherent(dev->core_dev->device,
			  sizeof(struct ce_gd) * PPC4XX_NUM_GD,
			  dev->gdr, dev->gdr_pa);
}

/*
 * when this function is called.
 * preemption or interrupt must be disabled
 */
u32 crypto4xx_get_n_gd(struct crypto4xx_device *dev, int n)
{
	u32 retval;
	u32 tmp;
	if (n >= PPC4XX_NUM_GD)
		return ERING_WAS_FULL;

	retval = dev->gdr_head;
	tmp = (dev->gdr_head + n) % PPC4XX_NUM_GD;
	if (dev->gdr_head > dev->gdr_tail) {
		if (tmp < dev->gdr_head && tmp >= dev->gdr_tail)
			return ERING_WAS_FULL;
	} else if (dev->gdr_head < dev->gdr_tail) {
		if (tmp < dev->gdr_head || tmp >= dev->gdr_tail)
			return ERING_WAS_FULL;
	}
	dev->gdr_head = tmp;

	return retval;
}

static u32 crypto4xx_put_gd_to_gdr(struct crypto4xx_device *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&dev->core_dev->lock, flags);
	if (dev->gdr_tail == dev->gdr_head) {
		spin_unlock_irqrestore(&dev->core_dev->lock, flags);
		return 0;
	}

	if (dev->gdr_tail != PPC4XX_LAST_GD)
		dev->gdr_tail++;
	else
		dev->gdr_tail = 0;

	spin_unlock_irqrestore(&dev->core_dev->lock, flags);

	return 0;
}

static inline struct ce_gd *crypto4xx_get_gdp(struct crypto4xx_device *dev,
					      dma_addr_t *gd_dma, u32 idx)
{
	*gd_dma = dev->gdr_pa + sizeof(struct ce_gd) * idx;

	return (struct ce_gd *) (dev->gdr + sizeof(struct ce_gd) * idx);
}

/**
 * alloc memory for the scatter ring
 * need to alloc buf for the ring
 * sdr_tail, sdr_head and sdr_count are initialized by this function
 */
static u32 crypto4xx_build_sdr(struct crypto4xx_device *dev)
{
	int i;
	struct ce_sd *sd_array;

	/* alloc memory for scatter descriptor ring */
	dev->sdr = dma_alloc_coherent(dev->core_dev->device,
				      sizeof(struct ce_sd) * PPC4XX_NUM_SD,
				      &dev->sdr_pa, GFP_ATOMIC);
	if (!dev->sdr)
		return -ENOMEM;

	dev->scatter_buffer_size = PPC4XX_SD_BUFFER_SIZE;
	dev->scatter_buffer_va =
		dma_alloc_coherent(dev->core_dev->device,
			dev->scatter_buffer_size * PPC4XX_NUM_SD,
			&dev->scatter_buffer_pa, GFP_ATOMIC);
	if (!dev->scatter_buffer_va) {
		dma_free_coherent(dev->core_dev->device,
				  sizeof(struct ce_sd) * PPC4XX_NUM_SD,
				  dev->sdr, dev->sdr_pa);
		return -ENOMEM;
	}

	sd_array = dev->sdr;

	for (i = 0; i < PPC4XX_NUM_SD; i++) {
		sd_array[i].ptr = dev->scatter_buffer_pa +
				  dev->scatter_buffer_size * i;
	}

	return 0;
}

static void crypto4xx_destroy_sdr(struct crypto4xx_device *dev)
{
	if (dev->sdr != NULL)
		dma_free_coherent(dev->core_dev->device,
				  sizeof(struct ce_sd) * PPC4XX_NUM_SD,
				  dev->sdr, dev->sdr_pa);

	if (dev->scatter_buffer_va != NULL)
		dma_free_coherent(dev->core_dev->device,
				  dev->scatter_buffer_size * PPC4XX_NUM_SD,
				  dev->scatter_buffer_va,
				  dev->scatter_buffer_pa);
}

/*
 * when this function is called.
 * preemption or interrupt must be disabled
 */
static u32 crypto4xx_get_n_sd(struct crypto4xx_device *dev, int n)
{
	u32 retval;
	u32 tmp;

	if (n >= PPC4XX_NUM_SD)
		return ERING_WAS_FULL;

	retval = dev->sdr_head;
	tmp = (dev->sdr_head + n) % PPC4XX_NUM_SD;
	if (dev->sdr_head > dev->gdr_tail) {
		if (tmp < dev->sdr_head && tmp >= dev->sdr_tail)
			return ERING_WAS_FULL;
	} else if (dev->sdr_head < dev->sdr_tail) {
		if (tmp < dev->sdr_head || tmp >= dev->sdr_tail)
			return ERING_WAS_FULL;
	} /* the head = tail, or empty case is already take cared */
	dev->sdr_head = tmp;

	return retval;
}

static u32 crypto4xx_put_sd_to_sdr(struct crypto4xx_device *dev)
{
	unsigned long flags;

	spin_lock_irqsave(&dev->core_dev->lock, flags);
	if (dev->sdr_tail == dev->sdr_head) {
		spin_unlock_irqrestore(&dev->core_dev->lock, flags);
		return 0;
	}
	if (dev->sdr_tail != PPC4XX_LAST_SD)
		dev->sdr_tail++;
	else
		dev->sdr_tail = 0;
	spin_unlock_irqrestore(&dev->core_dev->lock, flags);

	return 0;
}

static inline struct ce_sd *crypto4xx_get_sdp(struct crypto4xx_device *dev,
					      dma_addr_t *sd_dma, u32 idx)
{
	*sd_dma = dev->sdr_pa + sizeof(struct ce_sd) * idx;

	return  (struct ce_sd *)(dev->sdr + sizeof(struct ce_sd) * idx);
}

static u32 crypto4xx_fill_one_page(struct crypto4xx_device *dev,
				   dma_addr_t *addr, u32 *length,
				   u32 *idx, u32 *offset, u32 *nbytes)
{
	u32 len;

	if (*length > dev->scatter_buffer_size) {
		memcpy(phys_to_virt(*addr),
			dev->scatter_buffer_va +
			*idx * dev->scatter_buffer_size + *offset,
			dev->scatter_buffer_size);
		*offset = 0;
		*length -= dev->scatter_buffer_size;
		*nbytes -= dev->scatter_buffer_size;
		if (*idx == PPC4XX_LAST_SD)
			*idx = 0;
		else
			(*idx)++;
		*addr = *addr +  dev->scatter_buffer_size;
		return 1;
	} else if (*length < dev->scatter_buffer_size) {
		memcpy(phys_to_virt(*addr),
			dev->scatter_buffer_va +
			*idx * dev->scatter_buffer_size + *offset, *length);
		if ((*offset + *length) == dev->scatter_buffer_size) {
			if (*idx == PPC4XX_LAST_SD)
				*idx = 0;
			else
				(*idx)++;
			*nbytes -= *length;
			*offset = 0;
		} else {
			*nbytes -= *length;
			*offset += *length;
		}

		return 0;
	} else {
		len = (*nbytes <= dev->scatter_buffer_size) ?
				(*nbytes) : dev->scatter_buffer_size;
		memcpy(phys_to_virt(*addr),
			dev->scatter_buffer_va +
			*idx * dev->scatter_buffer_size + *offset,
			len);
		*offset = 0;
		*nbytes -= len;

		if (*idx == PPC4XX_LAST_SD)
			*idx = 0;
		else
			(*idx)++;

		return 0;
    }
}

static void crypto4xx_copy_pkt_to_dst(struct crypto4xx_device *dev,
				      struct ce_pd *pd,
				      struct pd_uinfo *pd_uinfo,
				      u32 nbytes,
				      struct scatterlist *dst)
{
	dma_addr_t addr;
	u32 this_sd;
	u32 offset;
	u32 len;
	u32 i;
	u32 sg_len;
	struct scatterlist *sg;

	this_sd = pd_uinfo->first_sd;
	offset = 0;
	i = 0;

	while (nbytes) {
		sg = &dst[i];
		sg_len = sg->length;
		addr = dma_map_page(dev->core_dev->device, sg_page(sg),
				sg->offset, sg->length, DMA_TO_DEVICE);

		if (offset == 0) {
			len = (nbytes <= sg->length) ? nbytes : sg->length;
			while (crypto4xx_fill_one_page(dev, &addr, &len,
				&this_sd, &offset, &nbytes))
				;
			if (!nbytes)
				return;
			i++;
		} else {
			len = (nbytes <= (dev->scatter_buffer_size - offset)) ?
				nbytes : (dev->scatter_buffer_size - offset);
			len = (sg->length < len) ? sg->length : len;
			while (crypto4xx_fill_one_page(dev, &addr, &len,
					       &this_sd, &offset, &nbytes))
				;
			if (!nbytes)
				return;
			sg_len -= len;
			if (sg_len) {
				addr += len;
				while (crypto4xx_fill_one_page(dev, &addr,
					&sg_len, &this_sd, &offset, &nbytes))
					;
			}
			i++;
		}
	}
}

static u32 crypto4xx_copy_digest_to_dst(struct pd_uinfo *pd_uinfo,
					struct crypto4xx_ctx *ctx)
{
	struct dynamic_sa_ctl *sa = (struct dynamic_sa_ctl *) ctx->sa_in;
	struct sa_state_record *state_record =
				(struct sa_state_record *) pd_uinfo->sr_va;

	if (sa->sa_command_0.bf.hash_alg == SA_HASH_ALG_SHA1) {
		memcpy((void *) pd_uinfo->dest_va, state_record->save_digest,
		       SA_HASH_ALG_SHA1_DIGEST_SIZE);
	}

	return 0;
}

static void crypto4xx_ret_sg_desc(struct crypto4xx_device *dev,
				  struct pd_uinfo *pd_uinfo)
{
	int i;
	if (pd_uinfo->num_gd) {
		for (i = 0; i < pd_uinfo->num_gd; i++)
			crypto4xx_put_gd_to_gdr(dev);
		pd_uinfo->first_gd = 0xffffffff;
		pd_uinfo->num_gd = 0;
	}
	if (pd_uinfo->num_sd) {
		for (i = 0; i < pd_uinfo->num_sd; i++)
			crypto4xx_put_sd_to_sdr(dev);

		pd_uinfo->first_sd = 0xffffffff;
		pd_uinfo->num_sd = 0;
	}
}

static u32 crypto4xx_ablkcipher_done(struct crypto4xx_device *dev,
				     struct pd_uinfo *pd_uinfo,
				     struct ce_pd *pd)
{
	struct crypto4xx_ctx *ctx;
	struct ablkcipher_request *ablk_req;
	struct scatterlist *dst;
	dma_addr_t addr;

	ablk_req = ablkcipher_request_cast(pd_uinfo->async_req);
	ctx  = crypto_tfm_ctx(ablk_req->base.tfm);

	if (pd_uinfo->using_sd) {
		crypto4xx_copy_pkt_to_dst(dev, pd, pd_uinfo, ablk_req->nbytes,
					  ablk_req->dst);
	} else {
		dst = pd_uinfo->dest_va;
		addr = dma_map_page(dev->core_dev->device, sg_page(dst),
				    dst->offset, dst->length, DMA_FROM_DEVICE);
	}
	crypto4xx_ret_sg_desc(dev, pd_uinfo);
	if (ablk_req->base.complete != NULL)
		ablk_req->base.complete(&ablk_req->base, 0);

	return 0;
}

static u32 crypto4xx_ahash_done(struct crypto4xx_device *dev,
				struct pd_uinfo *pd_uinfo)
{
	struct crypto4xx_ctx *ctx;
	struct ahash_request *ahash_req;

	ahash_req = ahash_request_cast(pd_uinfo->async_req);
	ctx  = crypto_tfm_ctx(ahash_req->base.tfm);

	crypto4xx_copy_digest_to_dst(pd_uinfo,
				     crypto_tfm_ctx(ahash_req->base.tfm));
	crypto4xx_ret_sg_desc(dev, pd_uinfo);
	/* call user provided callback function x */
	if (ahash_req->base.complete != NULL)
		ahash_req->base.complete(&ahash_req->base, 0);

	return 0;
}

static u32 crypto4xx_pd_done(struct crypto4xx_device *dev, u32 idx)
{
	struct ce_pd *pd;
	struct pd_uinfo *pd_uinfo;

	pd =  dev->pdr + sizeof(struct ce_pd)*idx;
	pd_uinfo = dev->pdr_uinfo + sizeof(struct pd_uinfo)*idx;
	if (crypto_tfm_alg_type(pd_uinfo->async_req->tfm) ==
			CRYPTO_ALG_TYPE_ABLKCIPHER)
		return crypto4xx_ablkcipher_done(dev, pd_uinfo, pd);
	else
		return crypto4xx_ahash_done(dev, pd_uinfo);
}

/**
 * Note: Only use this function to copy items that is word aligned.
 */
void crypto4xx_memcpy_le(unsigned int *dst,
			 const unsigned char *buf,
			 int len)
{
	u8 *tmp;
	for (; len >= 4; buf += 4, len -= 4)
		*dst++ = cpu_to_le32(*(unsigned int *) buf);

	tmp = (u8 *)dst;
	switch (len) {
	case 3:
		*tmp++ = 0;
		*tmp++ = *(buf+2);
		*tmp++ = *(buf+1);
		*tmp++ = *buf;
		break;
	case 2:
		*tmp++ = 0;
		*tmp++ = 0;
		*tmp++ = *(buf+1);
		*tmp++ = *buf;
		break;
	case 1:
		*tmp++ = 0;
		*tmp++ = 0;
		*tmp++ = 0;
		*tmp++ = *buf;
		break;
	default:
		break;
	}
}

static void crypto4xx_stop_all(struct crypto4xx_core_device *core_dev)
{
	crypto4xx_destroy_pdr(core_dev->dev);
	crypto4xx_destroy_gdr(core_dev->dev);
	crypto4xx_destroy_sdr(core_dev->dev);
	dev_set_drvdata(core_dev->device, NULL);
	iounmap(core_dev->dev->ce_base);
	kfree(core_dev->dev);
	kfree(core_dev);
}

void crypto4xx_return_pd(struct crypto4xx_device *dev,
			 u32 pd_entry, struct ce_pd *pd,
			 struct pd_uinfo *pd_uinfo)
{
	/* irq should be already disabled */
	dev->pdr_head = pd_entry;
	pd->pd_ctl.w = 0;
	pd->pd_ctl_len.w = 0;
	pd_uinfo->state = PD_ENTRY_FREE;
}

/*
 * derive number of elements in scatterlist
 * Shamlessly copy from talitos.c
 */
static int get_sg_count(struct scatterlist *sg_list, int nbytes)
{
	struct scatterlist *sg = sg_list;
	int sg_nents = 0;

	while (nbytes) {
		sg_nents++;
		if (sg->length > nbytes)
			break;
		nbytes -= sg->length;
		sg = sg_next(sg);
	}

	return sg_nents;
}

static u32 get_next_gd(u32 current)
{
	if (current != PPC4XX_LAST_GD)
		return current + 1;
	else
		return 0;
}

static u32 get_next_sd(u32 current)
{
	if (current != PPC4XX_LAST_SD)
		return current + 1;
	else
		return 0;
}

u32 crypto4xx_build_pd(struct crypto_async_request *req,
		       struct crypto4xx_ctx *ctx,
		       struct scatterlist *src,
		       struct scatterlist *dst,
		       unsigned int datalen,
		       void *iv, u32 iv_len)
{
	struct crypto4xx_device *dev = ctx->dev;
	dma_addr_t addr, pd_dma, sd_dma, gd_dma;
	struct dynamic_sa_ctl *sa;
	struct scatterlist *sg;
	struct ce_gd *gd;
	struct ce_pd *pd;
	u32 num_gd, num_sd;
	u32 fst_gd = 0xffffffff;
	u32 fst_sd = 0xffffffff;
	u32 pd_entry;
	unsigned long flags;
	struct pd_uinfo *pd_uinfo = NULL;
	unsigned int nbytes = datalen, idx;
	unsigned int ivlen = 0;
	u32 gd_idx = 0;

	/* figure how many gd is needed */
	num_gd = get_sg_count(src, datalen);
	if (num_gd == 1)
		num_gd = 0;

	/* figure how many sd is needed */
	if (sg_is_last(dst) || ctx->is_hash) {
		num_sd = 0;
	} else {
		if (datalen > PPC4XX_SD_BUFFER_SIZE) {
			num_sd = datalen / PPC4XX_SD_BUFFER_SIZE;
			if (datalen % PPC4XX_SD_BUFFER_SIZE)
				num_sd++;
		} else {
			num_sd = 1;
		}
	}

	/*
	 * The follow section of code needs to be protected
	 * The gather ring and scatter ring needs to be consecutive
	 * In case of run out of any kind of descriptor, the descriptor
	 * already got must be return the original place.
	 */
	spin_lock_irqsave(&dev->core_dev->lock, flags);
	if (num_gd) {
		fst_gd = crypto4xx_get_n_gd(dev, num_gd);
		if (fst_gd == ERING_WAS_FULL) {
			spin_unlock_irqrestore(&dev->core_dev->lock, flags);
			return -EAGAIN;
		}
	}
	if (num_sd) {
		fst_sd = crypto4xx_get_n_sd(dev, num_sd);
		if (fst_sd == ERING_WAS_FULL) {
			if (num_gd)
				dev->gdr_head = fst_gd;
			spin_unlock_irqrestore(&dev->core_dev->lock, flags);
			return -EAGAIN;
		}
	}
	pd_entry = crypto4xx_get_pd_from_pdr_nolock(dev);
	if (pd_entry == ERING_WAS_FULL) {
		if (num_gd)
			dev->gdr_head = fst_gd;
		if (num_sd)
			dev->sdr_head = fst_sd;
		spin_unlock_irqrestore(&dev->core_dev->lock, flags);
		return -EAGAIN;
	}
	spin_unlock_irqrestore(&dev->core_dev->lock, flags);

	pd_uinfo = (struct pd_uinfo *)(dev->pdr_uinfo +
				       sizeof(struct pd_uinfo) * pd_entry);
	pd = crypto4xx_get_pdp(dev, &pd_dma, pd_entry);
	pd_uinfo->async_req = req;
	pd_uinfo->num_gd = num_gd;
	pd_uinfo->num_sd = num_sd;

	if (iv_len || ctx->is_hash) {
		ivlen = iv_len;
		pd->sa = pd_uinfo->sa_pa;
		sa = (struct dynamic_sa_ctl *) pd_uinfo->sa_va;
		if (ctx->direction == DIR_INBOUND)
			memcpy(sa, ctx->sa_in, ctx->sa_len * 4);
		else
			memcpy(sa, ctx->sa_out, ctx->sa_len * 4);

		memcpy((void *) sa + ctx->offset_to_sr_ptr,
			&pd_uinfo->sr_pa, 4);

		if (iv_len)
			crypto4xx_memcpy_le(pd_uinfo->sr_va, iv, iv_len);
	} else {
		if (ctx->direction == DIR_INBOUND) {
			pd->sa = ctx->sa_in_dma_addr;
			sa = (struct dynamic_sa_ctl *) ctx->sa_in;
		} else {
			pd->sa = ctx->sa_out_dma_addr;
			sa = (struct dynamic_sa_ctl *) ctx->sa_out;
		}
	}
	pd->sa_len = ctx->sa_len;
	if (num_gd) {
		/* get first gd we are going to use */
		gd_idx = fst_gd;
		pd_uinfo->first_gd = fst_gd;
		pd_uinfo->num_gd = num_gd;
		gd = crypto4xx_get_gdp(dev, &gd_dma, gd_idx);
		pd->src = gd_dma;
		/* enable gather */
		sa->sa_command_0.bf.gather = 1;
		idx = 0;
		src = &src[0];
		/* walk the sg, and setup gather array */
		while (nbytes) {
			sg = &src[idx];
			addr = dma_map_page(dev->core_dev->device, sg_page(sg),
				    sg->offset, sg->length, DMA_TO_DEVICE);
			gd->ptr = addr;
			gd->ctl_len.len = sg->length;
			gd->ctl_len.done = 0;
			gd->ctl_len.ready = 1;
			if (sg->length >= nbytes)
				break;
			nbytes -= sg->length;
			gd_idx = get_next_gd(gd_idx);
			gd = crypto4xx_get_gdp(dev, &gd_dma, gd_idx);
			idx++;
		}
	} else {
		pd->src = (u32)dma_map_page(dev->core_dev->device, sg_page(src),
				src->offset, src->length, DMA_TO_DEVICE);
		/*
		 * Disable gather in sa command
		 */
		sa->sa_command_0.bf.gather = 0;
		/*
		 * Indicate gather array is not used
		 */
		pd_uinfo->first_gd = 0xffffffff;
		pd_uinfo->num_gd = 0;
	}
	if (ctx->is_hash || sg_is_last(dst)) {
		/*
		 * we know application give us dst a whole piece of memory
		 * no need to use scatter ring.
		 * In case of is_hash, the icv is always at end of src data.
		 */
		pd_uinfo->using_sd = 0;
		pd_uinfo->first_sd = 0xffffffff;
		pd_uinfo->num_sd = 0;
		pd_uinfo->dest_va = dst;
		sa->sa_command_0.bf.scatter = 0;
		if (ctx->is_hash)
			pd->dest = virt_to_phys((void *)dst);
		else
			pd->dest = (u32)dma_map_page(dev->core_dev->device,
					sg_page(dst), dst->offset,
					dst->length, DMA_TO_DEVICE);
	} else {
		struct ce_sd *sd = NULL;
		u32 sd_idx = fst_sd;
		nbytes = datalen;
		sa->sa_command_0.bf.scatter = 1;
		pd_uinfo->using_sd = 1;
		pd_uinfo->dest_va = dst;
		pd_uinfo->first_sd = fst_sd;
		pd_uinfo->num_sd = num_sd;
		sd = crypto4xx_get_sdp(dev, &sd_dma, sd_idx);
		pd->dest = sd_dma;
		/* setup scatter descriptor */
		sd->ctl.done = 0;
		sd->ctl.rdy = 1;
		/* sd->ptr should be setup by sd_init routine*/
		idx = 0;
		if (nbytes >= PPC4XX_SD_BUFFER_SIZE)
			nbytes -= PPC4XX_SD_BUFFER_SIZE;
		else
			nbytes = 0;
		while (nbytes) {
			sd_idx = get_next_sd(sd_idx);
			sd = crypto4xx_get_sdp(dev, &sd_dma, sd_idx);
			/* setup scatter descriptor */
			sd->ctl.done = 0;
			sd->ctl.rdy = 1;
			if (nbytes >= PPC4XX_SD_BUFFER_SIZE)
				nbytes -= PPC4XX_SD_BUFFER_SIZE;
			else
				/*
				 * SD entry can hold PPC4XX_SD_BUFFER_SIZE,
				 * which is more than nbytes, so done.
				 */
				nbytes = 0;
		}
	}

	sa->sa_command_1.bf.hash_crypto_offset = 0;
	pd->pd_ctl.w = ctx->pd_ctl;
	pd->pd_ctl_len.w = 0x00400000 | (ctx->bypass << 24) | datalen;
	pd_uinfo->state = PD_ENTRY_INUSE;
	wmb();
	/* write any value to push engine to read a pd */
	writel(1, dev->ce_base + CRYPTO4XX_INT_DESCR_RD);
	return -EINPROGRESS;
}

/**
 * Algorithm Registration Functions
 */
static int crypto4xx_alg_init(struct crypto_tfm *tfm)
{
	struct crypto_alg *alg = tfm->__crt_alg;
	struct crypto4xx_alg *amcc_alg = crypto_alg_to_crypto4xx_alg(alg);
	struct crypto4xx_ctx *ctx = crypto_tfm_ctx(tfm);

	ctx->dev = amcc_alg->dev;
	ctx->sa_in = NULL;
	ctx->sa_out = NULL;
	ctx->sa_in_dma_addr = 0;
	ctx->sa_out_dma_addr = 0;
	ctx->sa_len = 0;

	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
	default:
		tfm->crt_ablkcipher.reqsize = sizeof(struct crypto4xx_ctx);
		break;
	case CRYPTO_ALG_TYPE_AHASH:
		crypto_ahash_set_reqsize(__crypto_ahash_cast(tfm),
					 sizeof(struct crypto4xx_ctx));
		break;
	}

	return 0;
}

static void crypto4xx_alg_exit(struct crypto_tfm *tfm)
{
	struct crypto4xx_ctx *ctx = crypto_tfm_ctx(tfm);

	crypto4xx_free_sa(ctx);
	crypto4xx_free_state_record(ctx);
}

int crypto4xx_register_alg(struct crypto4xx_device *sec_dev,
			   struct crypto4xx_alg_common *crypto_alg,
			   int array_size)
{
	struct crypto4xx_alg *alg;
	int i;
	int rc = 0;

	for (i = 0; i < array_size; i++) {
		alg = kzalloc(sizeof(struct crypto4xx_alg), GFP_KERNEL);
		if (!alg)
			return -ENOMEM;

		alg->alg = crypto_alg[i];
		alg->dev = sec_dev;

		switch (alg->alg.type) {
		case CRYPTO_ALG_TYPE_AHASH:
			rc = crypto_register_ahash(&alg->alg.u.hash);
			break;

		default:
			rc = crypto_register_alg(&alg->alg.u.cipher);
			break;
		}

		if (rc) {
			list_del(&alg->entry);
			kfree(alg);
		} else {
			list_add_tail(&alg->entry, &sec_dev->alg_list);
		}
	}

	return 0;
}

static void crypto4xx_unregister_alg(struct crypto4xx_device *sec_dev)
{
	struct crypto4xx_alg *alg, *tmp;

	list_for_each_entry_safe(alg, tmp, &sec_dev->alg_list, entry) {
		list_del(&alg->entry);
		switch (alg->alg.type) {
		case CRYPTO_ALG_TYPE_AHASH:
			crypto_unregister_ahash(&alg->alg.u.hash);
			break;

		default:
			crypto_unregister_alg(&alg->alg.u.cipher);
		}
		kfree(alg);
	}
}

static void crypto4xx_bh_tasklet_cb(unsigned long data)
{
	struct device *dev = (struct device *)data;
	struct crypto4xx_core_device *core_dev = dev_get_drvdata(dev);
	struct pd_uinfo *pd_uinfo;
	struct ce_pd *pd;
	u32 tail;

	while (core_dev->dev->pdr_head != core_dev->dev->pdr_tail) {
		tail = core_dev->dev->pdr_tail;
		pd_uinfo = core_dev->dev->pdr_uinfo +
			sizeof(struct pd_uinfo)*tail;
		pd =  core_dev->dev->pdr + sizeof(struct ce_pd) * tail;
		if ((pd_uinfo->state == PD_ENTRY_INUSE) &&
				   pd->pd_ctl.bf.pe_done &&
				   !pd->pd_ctl.bf.host_ready) {
			pd->pd_ctl.bf.pe_done = 0;
			crypto4xx_pd_done(core_dev->dev, tail);
			crypto4xx_put_pd_to_pdr(core_dev->dev, tail);
			pd_uinfo->state = PD_ENTRY_FREE;
		} else {
			/* if tail not done, break */
			break;
		}
	}
}

/**
 * Top Half of isr.
 */
static irqreturn_t crypto4xx_ce_interrupt_handler(int irq, void *data)
{
	struct device *dev = (struct device *)data;
	struct crypto4xx_core_device *core_dev = dev_get_drvdata(dev);

	if (core_dev->dev->ce_base == 0)
		return 0;

	writel(PPC4XX_INTERRUPT_CLR,
	       core_dev->dev->ce_base + CRYPTO4XX_INT_CLR);
	tasklet_schedule(&core_dev->tasklet);

	return IRQ_HANDLED;
}

/**
 * Supported Crypto Algorithms
 */
struct crypto4xx_alg_common crypto4xx_alg[] = {
	/* Crypto AES modes */
	{ .type = CRYPTO_ALG_TYPE_ABLKCIPHER, .u.cipher = {
		.cra_name 	= "cbc(aes)",
		.cra_driver_name = "cbc-aes-ppc4xx",
		.cra_priority 	= CRYPTO4XX_CRYPTO_PRIORITY,
		.cra_flags 	= CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC,
		.cra_blocksize 	= AES_BLOCK_SIZE,
		.cra_ctxsize 	= sizeof(struct crypto4xx_ctx),
		.cra_type 	= &crypto_ablkcipher_type,
		.cra_init	= crypto4xx_alg_init,
		.cra_exit	= crypto4xx_alg_exit,
		.cra_module 	= THIS_MODULE,
		.cra_u 		= {
			.ablkcipher = {
				.min_keysize 	= AES_MIN_KEY_SIZE,
				.max_keysize 	= AES_MAX_KEY_SIZE,
				.ivsize		= AES_IV_SIZE,
				.setkey 	= crypto4xx_setkey_aes_cbc,
				.encrypt 	= crypto4xx_encrypt,
				.decrypt 	= crypto4xx_decrypt,
			}
		}
	}},
};

/**
 * Module Initialization Routine
 */
static int __init crypto4xx_probe(struct of_device *ofdev,
				  const struct of_device_id *match)
{
	int rc;
	struct resource res;
	struct device *dev = &ofdev->dev;
	struct crypto4xx_core_device *core_dev;

	rc = of_address_to_resource(ofdev->node, 0, &res);
	if (rc)
		return -ENODEV;

	if (of_find_compatible_node(NULL, NULL, "amcc,ppc460ex-crypto")) {
		mtdcri(SDR0, PPC460EX_SDR0_SRST,
		       mfdcri(SDR0, PPC460EX_SDR0_SRST) | PPC460EX_CE_RESET);
		mtdcri(SDR0, PPC460EX_SDR0_SRST,
		       mfdcri(SDR0, PPC460EX_SDR0_SRST) & ~PPC460EX_CE_RESET);
	} else if (of_find_compatible_node(NULL, NULL,
			"amcc,ppc405ex-crypto")) {
		mtdcri(SDR0, PPC405EX_SDR0_SRST,
		       mfdcri(SDR0, PPC405EX_SDR0_SRST) | PPC405EX_CE_RESET);
		mtdcri(SDR0, PPC405EX_SDR0_SRST,
		       mfdcri(SDR0, PPC405EX_SDR0_SRST) & ~PPC405EX_CE_RESET);
	} else if (of_find_compatible_node(NULL, NULL,
			"amcc,ppc460sx-crypto")) {
		mtdcri(SDR0, PPC460SX_SDR0_SRST,
		       mfdcri(SDR0, PPC460SX_SDR0_SRST) | PPC460SX_CE_RESET);
		mtdcri(SDR0, PPC460SX_SDR0_SRST,
		       mfdcri(SDR0, PPC460SX_SDR0_SRST) & ~PPC460SX_CE_RESET);
	} else {
		printk(KERN_ERR "Crypto Function Not supported!\n");
		return -EINVAL;
	}

	core_dev = kzalloc(sizeof(struct crypto4xx_core_device), GFP_KERNEL);
	if (!core_dev)
		return -ENOMEM;

	dev_set_drvdata(dev, core_dev);
	core_dev->ofdev = ofdev;
	core_dev->dev = kzalloc(sizeof(struct crypto4xx_device), GFP_KERNEL);
	if (!core_dev->dev)
		goto err_alloc_dev;

	core_dev->dev->core_dev = core_dev;
	core_dev->device = dev;
	spin_lock_init(&core_dev->lock);
	INIT_LIST_HEAD(&core_dev->dev->alg_list);
	rc = crypto4xx_build_pdr(core_dev->dev);
	if (rc)
		goto err_build_pdr;

	rc = crypto4xx_build_gdr(core_dev->dev);
	if (rc)
		goto err_build_gdr;

	rc = crypto4xx_build_sdr(core_dev->dev);
	if (rc)
		goto err_build_sdr;

	/* Init tasklet for bottom half processing */
	tasklet_init(&core_dev->tasklet, crypto4xx_bh_tasklet_cb,
		     (unsigned long) dev);

	/* Register for Crypto isr, Crypto Engine IRQ */
	core_dev->irq = irq_of_parse_and_map(ofdev->node, 0);
	rc = request_irq(core_dev->irq, crypto4xx_ce_interrupt_handler, 0,
			 core_dev->dev->name, dev);
	if (rc)
		goto err_request_irq;

	core_dev->dev->ce_base = of_iomap(ofdev->node, 0);
	if (!core_dev->dev->ce_base) {
		dev_err(dev, "failed to of_iomap\n");
		goto err_iomap;
	}

	/* need to setup pdr, rdr, gdr and sdr before this */
	crypto4xx_hw_init(core_dev->dev);

	/* Register security algorithms with Linux CryptoAPI */
	rc = crypto4xx_register_alg(core_dev->dev, crypto4xx_alg,
			       ARRAY_SIZE(crypto4xx_alg));
	if (rc)
		goto err_start_dev;

	return 0;

err_start_dev:
	iounmap(core_dev->dev->ce_base);
err_iomap:
	free_irq(core_dev->irq, dev);
	irq_dispose_mapping(core_dev->irq);
	tasklet_kill(&core_dev->tasklet);
err_request_irq:
	crypto4xx_destroy_sdr(core_dev->dev);
err_build_sdr:
	crypto4xx_destroy_gdr(core_dev->dev);
err_build_gdr:
	crypto4xx_destroy_pdr(core_dev->dev);
err_build_pdr:
	kfree(core_dev->dev);
err_alloc_dev:
	kfree(core_dev);

	return rc;
}

static int __exit crypto4xx_remove(struct of_device *ofdev)
{
	struct device *dev = &ofdev->dev;
	struct crypto4xx_core_device *core_dev = dev_get_drvdata(dev);

	free_irq(core_dev->irq, dev);
	irq_dispose_mapping(core_dev->irq);

	tasklet_kill(&core_dev->tasklet);
	/* Un-register with Linux CryptoAPI */
	crypto4xx_unregister_alg(core_dev->dev);
	/* Free all allocated memory */
	crypto4xx_stop_all(core_dev);

	return 0;
}

static struct of_device_id crypto4xx_match[] = {
	{ .compatible      = "amcc,ppc4xx-crypto",},
	{ },
};

static struct of_platform_driver crypto4xx_driver = {
	.name		= "crypto4xx",
	.match_table	= crypto4xx_match,
	.probe		= crypto4xx_probe,
	.remove		= crypto4xx_remove,
};

static int __init crypto4xx_init(void)
{
	return of_register_platform_driver(&crypto4xx_driver);
}

static void __exit crypto4xx_exit(void)
{
	of_unregister_platform_driver(&crypto4xx_driver);
}

module_init(crypto4xx_init);
module_exit(crypto4xx_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("James Hsiao <jhsiao@amcc.com>");
MODULE_DESCRIPTION("Driver for AMCC PPC4xx crypto accelerator");