root/drivers/crypto/atmel-tdes.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Cryptographic API.
 *
 * Support for ATMEL DES/TDES HW acceleration.
 *
 * Copyright (c) 2012 Eukréa Electromatique - ATMEL
 * Author: Nicolas Royer <nicolas@eukrea.com>
 *
 * Some ideas are from omap-aes.c drivers.
 */


#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/hw_random.h>
#include <linux/platform_device.h>

#include <linux/device.h>
#include <linux/dmaengine.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/mod_devicetable.h>
#include <linux/delay.h>
#include <linux/crypto.h>
#include <crypto/scatterwalk.h>
#include <crypto/algapi.h>
#include <crypto/internal/des.h>
#include <crypto/internal/skcipher.h>
#include "atmel-tdes-regs.h"

#define ATMEL_TDES_PRIORITY     300

/* TDES flags  */
/* Reserve bits [17:16], [13:12], [2:0] for AES Mode Register */
#define TDES_FLAGS_ENCRYPT      TDES_MR_CYPHER_ENC
#define TDES_FLAGS_OPMODE_MASK  (TDES_MR_OPMOD_MASK | TDES_MR_CFBS_MASK)
#define TDES_FLAGS_ECB          TDES_MR_OPMOD_ECB
#define TDES_FLAGS_CBC          TDES_MR_OPMOD_CBC

#define TDES_FLAGS_MODE_MASK    (TDES_FLAGS_OPMODE_MASK | TDES_FLAGS_ENCRYPT)

#define TDES_FLAGS_INIT         BIT(3)
#define TDES_FLAGS_FAST         BIT(4)
#define TDES_FLAGS_BUSY         BIT(5)
#define TDES_FLAGS_DMA          BIT(6)

#define ATMEL_TDES_QUEUE_LENGTH 50

struct atmel_tdes_caps {
        bool    has_dma;
};

struct atmel_tdes_dev;

struct atmel_tdes_ctx {
        struct atmel_tdes_dev *dd;

        int             keylen;
        u32             key[DES3_EDE_KEY_SIZE / sizeof(u32)];
        unsigned long   flags;

        u16             block_size;
};

struct atmel_tdes_reqctx {
        unsigned long mode;
        u8 lastc[DES_BLOCK_SIZE];
};

struct atmel_tdes_dma {
        struct dma_chan                 *chan;
        struct dma_slave_config dma_conf;
};

struct atmel_tdes_dev {
        struct list_head        list;
        unsigned long           phys_base;
        void __iomem            *io_base;

        struct atmel_tdes_ctx   *ctx;
        struct device           *dev;
        struct clk                      *iclk;
        int                                     irq;

        unsigned long           flags;

        spinlock_t              lock;
        struct crypto_queue     queue;

        struct tasklet_struct   done_task;
        struct tasklet_struct   queue_task;

        struct skcipher_request *req;
        size_t                          total;

        struct scatterlist      *in_sg;
        unsigned int            nb_in_sg;
        size_t                          in_offset;
        struct scatterlist      *out_sg;
        unsigned int            nb_out_sg;
        size_t                          out_offset;

        size_t  buflen;
        size_t  dma_size;

        void    *buf_in;
        int             dma_in;
        dma_addr_t      dma_addr_in;
        struct atmel_tdes_dma   dma_lch_in;

        void    *buf_out;
        int             dma_out;
        dma_addr_t      dma_addr_out;
        struct atmel_tdes_dma   dma_lch_out;

        struct atmel_tdes_caps  caps;

        u32     hw_version;
};

struct atmel_tdes_drv {
        struct list_head        dev_list;
        spinlock_t              lock;
};

static struct atmel_tdes_drv atmel_tdes = {
        .dev_list = LIST_HEAD_INIT(atmel_tdes.dev_list),
        .lock = __SPIN_LOCK_UNLOCKED(atmel_tdes.lock),
};

static int atmel_tdes_sg_copy(struct scatterlist **sg, size_t *offset,
                        void *buf, size_t buflen, size_t total, int out)
{
        size_t count, off = 0;

        while (buflen && total) {
                count = min((*sg)->length - *offset, total);
                count = min(count, buflen);

                if (!count)
                        return off;

                scatterwalk_map_and_copy(buf + off, *sg, *offset, count, out);

                off += count;
                buflen -= count;
                *offset += count;
                total -= count;

                if (*offset == (*sg)->length) {
                        *sg = sg_next(*sg);
                        if (*sg)
                                *offset = 0;
                        else
                                total = 0;
                }
        }

        return off;
}

static inline u32 atmel_tdes_read(struct atmel_tdes_dev *dd, u32 offset)
{
        return readl_relaxed(dd->io_base + offset);
}

static inline void atmel_tdes_write(struct atmel_tdes_dev *dd,
                                        u32 offset, u32 value)
{
        writel_relaxed(value, dd->io_base + offset);
}

static void atmel_tdes_write_n(struct atmel_tdes_dev *dd, u32 offset,
                               const u32 *value, int count)
{
        for (; count--; value++, offset += 4)
                atmel_tdes_write(dd, offset, *value);
}

static struct atmel_tdes_dev *atmel_tdes_dev_alloc(void)
{
        struct atmel_tdes_dev *tdes_dd;

        spin_lock_bh(&atmel_tdes.lock);
        /* One TDES IP per SoC. */
        tdes_dd = list_first_entry_or_null(&atmel_tdes.dev_list,
                                           struct atmel_tdes_dev, list);
        spin_unlock_bh(&atmel_tdes.lock);
        return tdes_dd;
}

static int atmel_tdes_hw_init(struct atmel_tdes_dev *dd)
{
        int err;

        err = clk_prepare_enable(dd->iclk);
        if (err)
                return err;

        if (!(dd->flags & TDES_FLAGS_INIT)) {
                atmel_tdes_write(dd, TDES_CR, TDES_CR_SWRST);
                dd->flags |= TDES_FLAGS_INIT;
        }

        return 0;
}

static inline unsigned int atmel_tdes_get_version(struct atmel_tdes_dev *dd)
{
        return atmel_tdes_read(dd, TDES_HW_VERSION) & 0x00000fff;
}

static int atmel_tdes_hw_version_init(struct atmel_tdes_dev *dd)
{
        int err;

        err = atmel_tdes_hw_init(dd);
        if (err)
                return err;

        dd->hw_version = atmel_tdes_get_version(dd);

        dev_info(dd->dev,
                        "version: 0x%x\n", dd->hw_version);

        clk_disable_unprepare(dd->iclk);

        return 0;
}

static void atmel_tdes_dma_callback(void *data)
{
        struct atmel_tdes_dev *dd = data;

        /* dma_lch_out - completed */
        tasklet_schedule(&dd->done_task);
}

static int atmel_tdes_write_ctrl(struct atmel_tdes_dev *dd)
{
        int err;
        u32 valmr = TDES_MR_SMOD_PDC;

        err = atmel_tdes_hw_init(dd);

        if (err)
                return err;

        if (!dd->caps.has_dma)
                atmel_tdes_write(dd, TDES_PTCR,
                        TDES_PTCR_TXTDIS | TDES_PTCR_RXTDIS);

        /* MR register must be set before IV registers */
        if (dd->ctx->keylen > (DES_KEY_SIZE << 1)) {
                valmr |= TDES_MR_KEYMOD_3KEY;
                valmr |= TDES_MR_TDESMOD_TDES;
        } else if (dd->ctx->keylen > DES_KEY_SIZE) {
                valmr |= TDES_MR_KEYMOD_2KEY;
                valmr |= TDES_MR_TDESMOD_TDES;
        } else {
                valmr |= TDES_MR_TDESMOD_DES;
        }

        valmr |= dd->flags & TDES_FLAGS_MODE_MASK;

        atmel_tdes_write(dd, TDES_MR, valmr);

        atmel_tdes_write_n(dd, TDES_KEY1W1R, dd->ctx->key,
                                                dd->ctx->keylen >> 2);

        if (dd->req->iv && (valmr & TDES_MR_OPMOD_MASK) != TDES_MR_OPMOD_ECB)
                atmel_tdes_write_n(dd, TDES_IV1R, (void *)dd->req->iv, 2);

        return 0;
}

static int atmel_tdes_crypt_pdc_stop(struct atmel_tdes_dev *dd)
{
        int err = 0;
        size_t count;

        atmel_tdes_write(dd, TDES_PTCR, TDES_PTCR_TXTDIS|TDES_PTCR_RXTDIS);

        if (dd->flags & TDES_FLAGS_FAST) {
                dma_unmap_sg(dd->dev, dd->out_sg, 1, DMA_FROM_DEVICE);
                dma_unmap_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
        } else {
                dma_sync_single_for_device(dd->dev, dd->dma_addr_out,
                                           dd->dma_size, DMA_FROM_DEVICE);

                /* copy data */
                count = atmel_tdes_sg_copy(&dd->out_sg, &dd->out_offset,
                                dd->buf_out, dd->buflen, dd->dma_size, 1);
                if (count != dd->dma_size) {
                        err = -EINVAL;
                        dev_dbg(dd->dev, "not all data converted: %zu\n", count);
                }
        }

        return err;
}

static int atmel_tdes_buff_init(struct atmel_tdes_dev *dd)
{
        int err = -ENOMEM;

        dd->buf_in = (void *)__get_free_pages(GFP_KERNEL, 0);
        dd->buf_out = (void *)__get_free_pages(GFP_KERNEL, 0);
        dd->buflen = PAGE_SIZE;
        dd->buflen &= ~(DES_BLOCK_SIZE - 1);

        if (!dd->buf_in || !dd->buf_out) {
                dev_dbg(dd->dev, "unable to alloc pages.\n");
                goto err_alloc;
        }

        /* MAP here */
        dd->dma_addr_in = dma_map_single(dd->dev, dd->buf_in,
                                        dd->buflen, DMA_TO_DEVICE);
        err = dma_mapping_error(dd->dev, dd->dma_addr_in);
        if (err) {
                dev_dbg(dd->dev, "dma %zd bytes error\n", dd->buflen);
                goto err_map_in;
        }

        dd->dma_addr_out = dma_map_single(dd->dev, dd->buf_out,
                                        dd->buflen, DMA_FROM_DEVICE);
        err = dma_mapping_error(dd->dev, dd->dma_addr_out);
        if (err) {
                dev_dbg(dd->dev, "dma %zd bytes error\n", dd->buflen);
                goto err_map_out;
        }

        return 0;

err_map_out:
        dma_unmap_single(dd->dev, dd->dma_addr_in, dd->buflen,
                DMA_TO_DEVICE);
err_map_in:
err_alloc:
        free_page((unsigned long)dd->buf_out);
        free_page((unsigned long)dd->buf_in);
        return err;
}

static void atmel_tdes_buff_cleanup(struct atmel_tdes_dev *dd)
{
        dma_unmap_single(dd->dev, dd->dma_addr_out, dd->buflen,
                         DMA_FROM_DEVICE);
        dma_unmap_single(dd->dev, dd->dma_addr_in, dd->buflen,
                DMA_TO_DEVICE);
        free_page((unsigned long)dd->buf_out);
        free_page((unsigned long)dd->buf_in);
}

static int atmel_tdes_crypt_pdc(struct atmel_tdes_dev *dd,
                                dma_addr_t dma_addr_in,
                                dma_addr_t dma_addr_out, int length)
{
        int len32;

        dd->dma_size = length;

        if (!(dd->flags & TDES_FLAGS_FAST)) {
                dma_sync_single_for_device(dd->dev, dma_addr_in, length,
                                           DMA_TO_DEVICE);
        }

        len32 = DIV_ROUND_UP(length, sizeof(u32));

        atmel_tdes_write(dd, TDES_PTCR, TDES_PTCR_TXTDIS|TDES_PTCR_RXTDIS);
        atmel_tdes_write(dd, TDES_TPR, dma_addr_in);
        atmel_tdes_write(dd, TDES_TCR, len32);
        atmel_tdes_write(dd, TDES_RPR, dma_addr_out);
        atmel_tdes_write(dd, TDES_RCR, len32);

        /* Enable Interrupt */
        atmel_tdes_write(dd, TDES_IER, TDES_INT_ENDRX);

        /* Start DMA transfer */
        atmel_tdes_write(dd, TDES_PTCR, TDES_PTCR_TXTEN | TDES_PTCR_RXTEN);

        return 0;
}

static int atmel_tdes_crypt_dma(struct atmel_tdes_dev *dd,
                                dma_addr_t dma_addr_in,
                                dma_addr_t dma_addr_out, int length)
{
        struct scatterlist sg[2];
        struct dma_async_tx_descriptor  *in_desc, *out_desc;
        enum dma_slave_buswidth addr_width;

        dd->dma_size = length;

        if (!(dd->flags & TDES_FLAGS_FAST)) {
                dma_sync_single_for_device(dd->dev, dma_addr_in, length,
                                           DMA_TO_DEVICE);
        }

        addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;

        dd->dma_lch_in.dma_conf.dst_addr_width = addr_width;
        dd->dma_lch_out.dma_conf.src_addr_width = addr_width;

        dmaengine_slave_config(dd->dma_lch_in.chan, &dd->dma_lch_in.dma_conf);
        dmaengine_slave_config(dd->dma_lch_out.chan, &dd->dma_lch_out.dma_conf);

        dd->flags |= TDES_FLAGS_DMA;

        sg_init_table(&sg[0], 1);
        sg_dma_address(&sg[0]) = dma_addr_in;
        sg_dma_len(&sg[0]) = length;

        sg_init_table(&sg[1], 1);
        sg_dma_address(&sg[1]) = dma_addr_out;
        sg_dma_len(&sg[1]) = length;

        in_desc = dmaengine_prep_slave_sg(dd->dma_lch_in.chan, &sg[0],
                                1, DMA_MEM_TO_DEV,
                                DMA_PREP_INTERRUPT  |  DMA_CTRL_ACK);
        if (!in_desc)
                return -EINVAL;

        out_desc = dmaengine_prep_slave_sg(dd->dma_lch_out.chan, &sg[1],
                                1, DMA_DEV_TO_MEM,
                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!out_desc)
                return -EINVAL;

        out_desc->callback = atmel_tdes_dma_callback;
        out_desc->callback_param = dd;

        dmaengine_submit(out_desc);
        dma_async_issue_pending(dd->dma_lch_out.chan);

        dmaengine_submit(in_desc);
        dma_async_issue_pending(dd->dma_lch_in.chan);

        return 0;
}

static int atmel_tdes_crypt_start(struct atmel_tdes_dev *dd)
{
        int err, fast = 0, in, out;
        size_t count;
        dma_addr_t addr_in, addr_out;

        if ((!dd->in_offset) && (!dd->out_offset)) {
                /* check for alignment */
                in = IS_ALIGNED((u32)dd->in_sg->offset, sizeof(u32)) &&
                        IS_ALIGNED(dd->in_sg->length, dd->ctx->block_size);
                out = IS_ALIGNED((u32)dd->out_sg->offset, sizeof(u32)) &&
                        IS_ALIGNED(dd->out_sg->length, dd->ctx->block_size);
                fast = in && out;

                if (sg_dma_len(dd->in_sg) != sg_dma_len(dd->out_sg))
                        fast = 0;
        }


        if (fast)  {
                count = min_t(size_t, dd->total, sg_dma_len(dd->in_sg));
                count = min_t(size_t, count, sg_dma_len(dd->out_sg));

                err = dma_map_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
                if (!err) {
                        dev_dbg(dd->dev, "dma_map_sg() error\n");
                        return -EINVAL;
                }

                err = dma_map_sg(dd->dev, dd->out_sg, 1,
                                DMA_FROM_DEVICE);
                if (!err) {
                        dev_dbg(dd->dev, "dma_map_sg() error\n");
                        dma_unmap_sg(dd->dev, dd->in_sg, 1,
                                DMA_TO_DEVICE);
                        return -EINVAL;
                }

                addr_in = sg_dma_address(dd->in_sg);
                addr_out = sg_dma_address(dd->out_sg);

                dd->flags |= TDES_FLAGS_FAST;

        } else {
                /* use cache buffers */
                count = atmel_tdes_sg_copy(&dd->in_sg, &dd->in_offset,
                                dd->buf_in, dd->buflen, dd->total, 0);

                addr_in = dd->dma_addr_in;
                addr_out = dd->dma_addr_out;

                dd->flags &= ~TDES_FLAGS_FAST;
        }

        dd->total -= count;

        if (dd->caps.has_dma)
                err = atmel_tdes_crypt_dma(dd, addr_in, addr_out, count);
        else
                err = atmel_tdes_crypt_pdc(dd, addr_in, addr_out, count);

        if (err && (dd->flags & TDES_FLAGS_FAST)) {
                dma_unmap_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
                dma_unmap_sg(dd->dev, dd->out_sg, 1, DMA_FROM_DEVICE);
        }

        return err;
}

static void
atmel_tdes_set_iv_as_last_ciphertext_block(struct atmel_tdes_dev *dd)
{
        struct skcipher_request *req = dd->req;
        struct atmel_tdes_reqctx *rctx = skcipher_request_ctx(req);
        struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
        unsigned int ivsize = crypto_skcipher_ivsize(skcipher);

        if (req->cryptlen < ivsize)
                return;

        if (rctx->mode & TDES_FLAGS_ENCRYPT)
                scatterwalk_map_and_copy(req->iv, req->dst,
                                         req->cryptlen - ivsize, ivsize, 0);
        else
                memcpy(req->iv, rctx->lastc, ivsize);

}

static void atmel_tdes_finish_req(struct atmel_tdes_dev *dd, int err)
{
        struct skcipher_request *req = dd->req;
        struct atmel_tdes_reqctx *rctx = skcipher_request_ctx(req);

        clk_disable_unprepare(dd->iclk);

        dd->flags &= ~TDES_FLAGS_BUSY;

        if (!err && (rctx->mode & TDES_FLAGS_OPMODE_MASK) != TDES_FLAGS_ECB)
                atmel_tdes_set_iv_as_last_ciphertext_block(dd);

        skcipher_request_complete(req, err);
}

static int atmel_tdes_handle_queue(struct atmel_tdes_dev *dd,
                               struct skcipher_request *req)
{
        struct crypto_async_request *async_req, *backlog;
        struct atmel_tdes_ctx *ctx;
        struct atmel_tdes_reqctx *rctx;
        unsigned long flags;
        int err, ret = 0;

        spin_lock_irqsave(&dd->lock, flags);
        if (req)
                ret = crypto_enqueue_request(&dd->queue, &req->base);
        if (dd->flags & TDES_FLAGS_BUSY) {
                spin_unlock_irqrestore(&dd->lock, flags);
                return ret;
        }
        backlog = crypto_get_backlog(&dd->queue);
        async_req = crypto_dequeue_request(&dd->queue);
        if (async_req)
                dd->flags |= TDES_FLAGS_BUSY;
        spin_unlock_irqrestore(&dd->lock, flags);

        if (!async_req)
                return ret;

        if (backlog)
                crypto_request_complete(backlog, -EINPROGRESS);

        req = skcipher_request_cast(async_req);

        /* assign new request to device */
        dd->req = req;
        dd->total = req->cryptlen;
        dd->in_offset = 0;
        dd->in_sg = req->src;
        dd->out_offset = 0;
        dd->out_sg = req->dst;

        rctx = skcipher_request_ctx(req);
        ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
        rctx->mode &= TDES_FLAGS_MODE_MASK;
        dd->flags = (dd->flags & ~TDES_FLAGS_MODE_MASK) | rctx->mode;
        dd->ctx = ctx;

        err = atmel_tdes_write_ctrl(dd);
        if (!err)
                err = atmel_tdes_crypt_start(dd);
        if (err) {
                /* des_task will not finish it, so do it here */
                atmel_tdes_finish_req(dd, err);
                tasklet_schedule(&dd->queue_task);
        }

        return ret;
}

static int atmel_tdes_crypt_dma_stop(struct atmel_tdes_dev *dd)
{
        int err = -EINVAL;
        size_t count;

        if (dd->flags & TDES_FLAGS_DMA) {
                err = 0;
                if  (dd->flags & TDES_FLAGS_FAST) {
                        dma_unmap_sg(dd->dev, dd->out_sg, 1, DMA_FROM_DEVICE);
                        dma_unmap_sg(dd->dev, dd->in_sg, 1, DMA_TO_DEVICE);
                } else {
                        dma_sync_single_for_device(dd->dev, dd->dma_addr_out,
                                dd->dma_size, DMA_FROM_DEVICE);

                        /* copy data */
                        count = atmel_tdes_sg_copy(&dd->out_sg, &dd->out_offset,
                                dd->buf_out, dd->buflen, dd->dma_size, 1);
                        if (count != dd->dma_size) {
                                err = -EINVAL;
                                dev_dbg(dd->dev, "not all data converted: %zu\n", count);
                        }
                }
        }
        return err;
}

static int atmel_tdes_crypt(struct skcipher_request *req, unsigned long mode)
{
        struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
        struct atmel_tdes_ctx *ctx = crypto_skcipher_ctx(skcipher);
        struct atmel_tdes_reqctx *rctx = skcipher_request_ctx(req);
        struct device *dev = ctx->dd->dev;

        if (!req->cryptlen)
                return 0;

        if (!IS_ALIGNED(req->cryptlen, DES_BLOCK_SIZE)) {
                dev_dbg(dev, "request size is not exact amount of DES blocks\n");
                return -EINVAL;
        }
        ctx->block_size = DES_BLOCK_SIZE;

        rctx->mode = mode;

        if ((mode & TDES_FLAGS_OPMODE_MASK) != TDES_FLAGS_ECB &&
            !(mode & TDES_FLAGS_ENCRYPT)) {
                unsigned int ivsize = crypto_skcipher_ivsize(skcipher);

                if (req->cryptlen >= ivsize)
                        scatterwalk_map_and_copy(rctx->lastc, req->src,
                                                 req->cryptlen - ivsize,
                                                 ivsize, 0);
        }

        return atmel_tdes_handle_queue(ctx->dd, req);
}

static int atmel_tdes_dma_init(struct atmel_tdes_dev *dd)
{
        int ret;

        /* Try to grab 2 DMA channels */
        dd->dma_lch_in.chan = dma_request_chan(dd->dev, "tx");
        if (IS_ERR(dd->dma_lch_in.chan)) {
                ret = PTR_ERR(dd->dma_lch_in.chan);
                goto err_dma_in;
        }

        dd->dma_lch_in.dma_conf.dst_addr = dd->phys_base +
                TDES_IDATA1R;
        dd->dma_lch_in.dma_conf.src_maxburst = 1;
        dd->dma_lch_in.dma_conf.src_addr_width =
                DMA_SLAVE_BUSWIDTH_4_BYTES;
        dd->dma_lch_in.dma_conf.dst_maxburst = 1;
        dd->dma_lch_in.dma_conf.dst_addr_width =
                DMA_SLAVE_BUSWIDTH_4_BYTES;
        dd->dma_lch_in.dma_conf.device_fc = false;

        dd->dma_lch_out.chan = dma_request_chan(dd->dev, "rx");
        if (IS_ERR(dd->dma_lch_out.chan)) {
                ret = PTR_ERR(dd->dma_lch_out.chan);
                goto err_dma_out;
        }

        dd->dma_lch_out.dma_conf.src_addr = dd->phys_base +
                TDES_ODATA1R;
        dd->dma_lch_out.dma_conf.src_maxburst = 1;
        dd->dma_lch_out.dma_conf.src_addr_width =
                DMA_SLAVE_BUSWIDTH_4_BYTES;
        dd->dma_lch_out.dma_conf.dst_maxburst = 1;
        dd->dma_lch_out.dma_conf.dst_addr_width =
                DMA_SLAVE_BUSWIDTH_4_BYTES;
        dd->dma_lch_out.dma_conf.device_fc = false;

        return 0;

err_dma_out:
        dma_release_channel(dd->dma_lch_in.chan);
err_dma_in:
        dev_err(dd->dev, "no DMA channel available\n");
        return ret;
}

static void atmel_tdes_dma_cleanup(struct atmel_tdes_dev *dd)
{
        dma_release_channel(dd->dma_lch_in.chan);
        dma_release_channel(dd->dma_lch_out.chan);
}

static int atmel_des_setkey(struct crypto_skcipher *tfm, const u8 *key,
                           unsigned int keylen)
{
        struct atmel_tdes_ctx *ctx = crypto_skcipher_ctx(tfm);
        int err;

        err = verify_skcipher_des_key(tfm, key);
        if (err)
                return err;

        memcpy(ctx->key, key, keylen);
        ctx->keylen = keylen;

        return 0;
}

static int atmel_tdes_setkey(struct crypto_skcipher *tfm, const u8 *key,
                           unsigned int keylen)
{
        struct atmel_tdes_ctx *ctx = crypto_skcipher_ctx(tfm);
        int err;

        err = verify_skcipher_des3_key(tfm, key);
        if (err)
                return err;

        memcpy(ctx->key, key, keylen);
        ctx->keylen = keylen;

        return 0;
}

static int atmel_tdes_ecb_encrypt(struct skcipher_request *req)
{
        return atmel_tdes_crypt(req, TDES_FLAGS_ECB | TDES_FLAGS_ENCRYPT);
}

static int atmel_tdes_ecb_decrypt(struct skcipher_request *req)
{
        return atmel_tdes_crypt(req, TDES_FLAGS_ECB);
}

static int atmel_tdes_cbc_encrypt(struct skcipher_request *req)
{
        return atmel_tdes_crypt(req, TDES_FLAGS_CBC | TDES_FLAGS_ENCRYPT);
}

static int atmel_tdes_cbc_decrypt(struct skcipher_request *req)
{
        return atmel_tdes_crypt(req, TDES_FLAGS_CBC);
}

static int atmel_tdes_init_tfm(struct crypto_skcipher *tfm)
{
        struct atmel_tdes_ctx *ctx = crypto_skcipher_ctx(tfm);

        ctx->dd = atmel_tdes_dev_alloc();
        if (!ctx->dd)
                return -ENODEV;

        crypto_skcipher_set_reqsize(tfm, sizeof(struct atmel_tdes_reqctx));

        return 0;
}

static void atmel_tdes_skcipher_alg_init(struct skcipher_alg *alg)
{
        alg->base.cra_priority = ATMEL_TDES_PRIORITY;
        alg->base.cra_flags = CRYPTO_ALG_ASYNC | CRYPTO_ALG_KERN_DRIVER_ONLY;
        alg->base.cra_ctxsize = sizeof(struct atmel_tdes_ctx);
        alg->base.cra_module = THIS_MODULE;

        alg->init = atmel_tdes_init_tfm;
}

static struct skcipher_alg tdes_algs[] = {
{
        .base.cra_name          = "ecb(des)",
        .base.cra_driver_name   = "atmel-ecb-des",
        .base.cra_blocksize     = DES_BLOCK_SIZE,
        .base.cra_alignmask     = 0x7,

        .min_keysize            = DES_KEY_SIZE,
        .max_keysize            = DES_KEY_SIZE,
        .setkey                 = atmel_des_setkey,
        .encrypt                = atmel_tdes_ecb_encrypt,
        .decrypt                = atmel_tdes_ecb_decrypt,
},
{
        .base.cra_name          = "cbc(des)",
        .base.cra_driver_name   = "atmel-cbc-des",
        .base.cra_blocksize     = DES_BLOCK_SIZE,
        .base.cra_alignmask     = 0x7,

        .min_keysize            = DES_KEY_SIZE,
        .max_keysize            = DES_KEY_SIZE,
        .ivsize                 = DES_BLOCK_SIZE,
        .setkey                 = atmel_des_setkey,
        .encrypt                = atmel_tdes_cbc_encrypt,
        .decrypt                = atmel_tdes_cbc_decrypt,
},
{
        .base.cra_name          = "ecb(des3_ede)",
        .base.cra_driver_name   = "atmel-ecb-tdes",
        .base.cra_blocksize     = DES_BLOCK_SIZE,
        .base.cra_alignmask     = 0x7,

        .min_keysize            = DES3_EDE_KEY_SIZE,
        .max_keysize            = DES3_EDE_KEY_SIZE,
        .setkey                 = atmel_tdes_setkey,
        .encrypt                = atmel_tdes_ecb_encrypt,
        .decrypt                = atmel_tdes_ecb_decrypt,
},
{
        .base.cra_name          = "cbc(des3_ede)",
        .base.cra_driver_name   = "atmel-cbc-tdes",
        .base.cra_blocksize     = DES_BLOCK_SIZE,
        .base.cra_alignmask     = 0x7,

        .min_keysize            = DES3_EDE_KEY_SIZE,
        .max_keysize            = DES3_EDE_KEY_SIZE,
        .setkey                 = atmel_tdes_setkey,
        .encrypt                = atmel_tdes_cbc_encrypt,
        .decrypt                = atmel_tdes_cbc_decrypt,
        .ivsize                 = DES_BLOCK_SIZE,
},
};

static void atmel_tdes_queue_task(unsigned long data)
{
        struct atmel_tdes_dev *dd = (struct atmel_tdes_dev *)data;

        atmel_tdes_handle_queue(dd, NULL);
}

static void atmel_tdes_done_task(unsigned long data)
{
        struct atmel_tdes_dev *dd = (struct atmel_tdes_dev *) data;
        int err;

        if (!(dd->flags & TDES_FLAGS_DMA))
                err = atmel_tdes_crypt_pdc_stop(dd);
        else
                err = atmel_tdes_crypt_dma_stop(dd);

        if (dd->total && !err) {
                if (dd->flags & TDES_FLAGS_FAST) {
                        dd->in_sg = sg_next(dd->in_sg);
                        dd->out_sg = sg_next(dd->out_sg);
                        if (!dd->in_sg || !dd->out_sg)
                                err = -EINVAL;
                }
                if (!err)
                        err = atmel_tdes_crypt_start(dd);
                if (!err)
                        return; /* DMA started. Not finishing. */
        }

        atmel_tdes_finish_req(dd, err);
        atmel_tdes_handle_queue(dd, NULL);
}

static irqreturn_t atmel_tdes_irq(int irq, void *dev_id)
{
        struct atmel_tdes_dev *tdes_dd = dev_id;
        u32 reg;

        reg = atmel_tdes_read(tdes_dd, TDES_ISR);
        if (reg & atmel_tdes_read(tdes_dd, TDES_IMR)) {
                atmel_tdes_write(tdes_dd, TDES_IDR, reg);
                if (TDES_FLAGS_BUSY & tdes_dd->flags)
                        tasklet_schedule(&tdes_dd->done_task);
                else
                        dev_warn(tdes_dd->dev, "TDES interrupt when no active requests.\n");
                return IRQ_HANDLED;
        }

        return IRQ_NONE;
}

static int atmel_tdes_register_algs(struct atmel_tdes_dev *dd)
{
        int err, i;

        for (i = 0; i < ARRAY_SIZE(tdes_algs); i++) {
                atmel_tdes_skcipher_alg_init(&tdes_algs[i]);

                err = crypto_register_skcipher(&tdes_algs[i]);
                if (err) {
                        crypto_unregister_skciphers(tdes_algs, i);
                        return err;
                }
        }

        return 0;
}

static void atmel_tdes_get_cap(struct atmel_tdes_dev *dd)
{
        dd->caps.has_dma = 0;

        /* keep only major version number */
        switch (dd->hw_version & 0xf00) {
        case 0x800:
        case 0x700:
                dd->caps.has_dma = 1;
                break;
        case 0x600:
                break;
        default:
                dev_warn(dd->dev,
                                "Unmanaged tdes version, set minimum capabilities\n");
                break;
        }
}

static const struct of_device_id atmel_tdes_dt_ids[] = {
        { .compatible = "atmel,at91sam9g46-tdes" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, atmel_tdes_dt_ids);

static int atmel_tdes_probe(struct platform_device *pdev)
{
        struct atmel_tdes_dev *tdes_dd;
        struct device *dev = &pdev->dev;
        struct resource *tdes_res;
        int err;

        tdes_dd = devm_kmalloc(&pdev->dev, sizeof(*tdes_dd), GFP_KERNEL);
        if (!tdes_dd)
                return -ENOMEM;

        tdes_dd->dev = dev;

        platform_set_drvdata(pdev, tdes_dd);

        INIT_LIST_HEAD(&tdes_dd->list);
        spin_lock_init(&tdes_dd->lock);

        tasklet_init(&tdes_dd->done_task, atmel_tdes_done_task,
                                        (unsigned long)tdes_dd);
        tasklet_init(&tdes_dd->queue_task, atmel_tdes_queue_task,
                                        (unsigned long)tdes_dd);

        crypto_init_queue(&tdes_dd->queue, ATMEL_TDES_QUEUE_LENGTH);

        tdes_dd->io_base = devm_platform_get_and_ioremap_resource(pdev, 0, &tdes_res);
        if (IS_ERR(tdes_dd->io_base)) {
                err = PTR_ERR(tdes_dd->io_base);
                goto err_tasklet_kill;
        }
        tdes_dd->phys_base = tdes_res->start;

        /* Get the IRQ */
        tdes_dd->irq = platform_get_irq(pdev,  0);
        if (tdes_dd->irq < 0) {
                err = tdes_dd->irq;
                goto err_tasklet_kill;
        }

        err = devm_request_irq(&pdev->dev, tdes_dd->irq, atmel_tdes_irq,
                               IRQF_SHARED, "atmel-tdes", tdes_dd);
        if (err) {
                dev_err(dev, "unable to request tdes irq.\n");
                goto err_tasklet_kill;
        }

        /* Initializing the clock */
        tdes_dd->iclk = devm_clk_get(&pdev->dev, "tdes_clk");
        if (IS_ERR(tdes_dd->iclk)) {
                dev_err(dev, "clock initialization failed.\n");
                err = PTR_ERR(tdes_dd->iclk);
                goto err_tasklet_kill;
        }

        err = atmel_tdes_hw_version_init(tdes_dd);
        if (err)
                goto err_tasklet_kill;

        atmel_tdes_get_cap(tdes_dd);

        err = atmel_tdes_buff_init(tdes_dd);
        if (err)
                goto err_tasklet_kill;

        if (tdes_dd->caps.has_dma) {
                err = atmel_tdes_dma_init(tdes_dd);
                if (err)
                        goto err_buff_cleanup;

                dev_info(dev, "using %s, %s for DMA transfers\n",
                                dma_chan_name(tdes_dd->dma_lch_in.chan),
                                dma_chan_name(tdes_dd->dma_lch_out.chan));
        }

        spin_lock(&atmel_tdes.lock);
        list_add_tail(&tdes_dd->list, &atmel_tdes.dev_list);
        spin_unlock(&atmel_tdes.lock);

        err = atmel_tdes_register_algs(tdes_dd);
        if (err)
                goto err_algs;

        dev_info(dev, "Atmel DES/TDES\n");

        return 0;

err_algs:
        spin_lock(&atmel_tdes.lock);
        list_del(&tdes_dd->list);
        spin_unlock(&atmel_tdes.lock);
        if (tdes_dd->caps.has_dma)
                atmel_tdes_dma_cleanup(tdes_dd);
err_buff_cleanup:
        atmel_tdes_buff_cleanup(tdes_dd);
err_tasklet_kill:
        tasklet_kill(&tdes_dd->done_task);
        tasklet_kill(&tdes_dd->queue_task);

        return err;
}

static void atmel_tdes_remove(struct platform_device *pdev)
{
        struct atmel_tdes_dev *tdes_dd = platform_get_drvdata(pdev);

        spin_lock(&atmel_tdes.lock);
        list_del(&tdes_dd->list);
        spin_unlock(&atmel_tdes.lock);

        crypto_unregister_skciphers(tdes_algs, ARRAY_SIZE(tdes_algs));

        tasklet_kill(&tdes_dd->done_task);
        tasklet_kill(&tdes_dd->queue_task);

        if (tdes_dd->caps.has_dma)
                atmel_tdes_dma_cleanup(tdes_dd);

        atmel_tdes_buff_cleanup(tdes_dd);
}

static struct platform_driver atmel_tdes_driver = {
        .probe          = atmel_tdes_probe,
        .remove         = atmel_tdes_remove,
        .driver         = {
                .name   = "atmel_tdes",
                .of_match_table = atmel_tdes_dt_ids,
        },
};

module_platform_driver(atmel_tdes_driver);

MODULE_DESCRIPTION("Atmel DES/TDES hw acceleration support.");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Nicolas Royer - Eukréa Electromatique");