// SPDX-License-Identifier: GPL-2.0
/*
 * sun8i-ce-prng.c - hardware cryptographic offloader for
 * Allwinner H3/A64/H5/H2+/H6/R40 SoC
 *
 * Copyright (C) 2015-2020 Corentin Labbe <clabbe@baylibre.com>
 *
 * This file handle the PRNG
 *
 * You could find a link for the datasheet in Documentation/arch/arm/sunxi.rst
 */
#include "sun8i-ce.h"
#include <linux/dma-mapping.h>
#include <linux/pm_runtime.h>
#include <crypto/internal/rng.h>

int sun8i_ce_prng_init(struct crypto_tfm *tfm)
{
        struct sun8i_ce_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);

        memset(ctx, 0, sizeof(struct sun8i_ce_rng_tfm_ctx));
        return 0;
}

void sun8i_ce_prng_exit(struct crypto_tfm *tfm)
{
        struct sun8i_ce_rng_tfm_ctx *ctx = crypto_tfm_ctx(tfm);

        kfree_sensitive(ctx->seed);
        ctx->seed = NULL;
        ctx->slen = 0;
}

int sun8i_ce_prng_seed(struct crypto_rng *tfm, const u8 *seed,
                       unsigned int slen)
{
        struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);

        if (ctx->seed && ctx->slen != slen) {
                kfree_sensitive(ctx->seed);
                ctx->slen = 0;
                ctx->seed = NULL;
        }
        if (!ctx->seed)
                ctx->seed = kmalloc(slen, GFP_KERNEL | GFP_DMA);
        if (!ctx->seed)
                return -ENOMEM;

        memcpy(ctx->seed, seed, slen);
        ctx->slen = slen;

        return 0;
}

int sun8i_ce_prng_generate(struct crypto_rng *tfm, const u8 *src,
                           unsigned int slen, u8 *dst, unsigned int dlen)
{
        struct sun8i_ce_rng_tfm_ctx *ctx = crypto_rng_ctx(tfm);
        struct rng_alg *alg = crypto_rng_alg(tfm);
        struct sun8i_ce_alg_template *algt;
        struct sun8i_ce_dev *ce;
        dma_addr_t dma_iv, dma_dst;
        int err = 0;
        int flow = 3;
        unsigned int todo;
        struct sun8i_ce_flow *chan;
        struct ce_task *cet;
        u32 common, sym;
        void *d;

        algt = container_of(alg, struct sun8i_ce_alg_template, alg.rng);
        ce = algt->ce;

        if (ctx->slen == 0) {
                dev_err(ce->dev, "not seeded\n");
                return -EINVAL;
        }

        /* we want dlen + seedsize rounded up to a multiple of PRNG_DATA_SIZE */
        todo = dlen + ctx->slen + PRNG_DATA_SIZE * 2;
        todo -= todo % PRNG_DATA_SIZE;

        d = kzalloc(todo, GFP_KERNEL | GFP_DMA);
        if (!d) {
                err = -ENOMEM;
                goto err_mem;
        }

        dev_dbg(ce->dev, "%s PRNG slen=%u dlen=%u todo=%u multi=%u\n", __func__,
                slen, dlen, todo, todo / PRNG_DATA_SIZE);

#ifdef CONFIG_CRYPTO_DEV_SUN8I_CE_DEBUG
        algt->stat_req++;
        algt->stat_bytes += todo;
#endif

        dma_iv = dma_map_single(ce->dev, ctx->seed, ctx->slen, DMA_TO_DEVICE);
        if (dma_mapping_error(ce->dev, dma_iv)) {
                dev_err(ce->dev, "Cannot DMA MAP IV\n");
                err = -EFAULT;
                goto err_iv;
        }

        dma_dst = dma_map_single(ce->dev, d, todo, DMA_FROM_DEVICE);
        if (dma_mapping_error(ce->dev, dma_dst)) {
                dev_err(ce->dev, "Cannot DMA MAP DST\n");
                err = -EFAULT;
                goto err_dst;
        }

        err = pm_runtime_resume_and_get(ce->dev);
        if (err < 0)
                goto err_pm;

        mutex_lock(&ce->rnglock);
        chan = &ce->chanlist[flow];

        cet = &chan->tl[0];
        memset(cet, 0, sizeof(struct ce_task));

        cet->t_id = cpu_to_le32(flow);
        common = ce->variant->prng | CE_COMM_INT;
        cet->t_common_ctl = cpu_to_le32(common);

        /* recent CE (H6) need length in bytes, in word otherwise */
        if (ce->variant->prng_t_dlen_in_bytes)
                cet->t_dlen = cpu_to_le32(todo);
        else
                cet->t_dlen = cpu_to_le32(todo / 4);

        sym = PRNG_LD;
        cet->t_sym_ctl = cpu_to_le32(sym);
        cet->t_asym_ctl = 0;

        cet->t_key = desc_addr_val_le32(ce, dma_iv);
        cet->t_iv = desc_addr_val_le32(ce, dma_iv);

        cet->t_dst[0].addr = desc_addr_val_le32(ce, dma_dst);
        cet->t_dst[0].len = cpu_to_le32(todo / 4);

        err = sun8i_ce_run_task(ce, 3, "PRNG");
        mutex_unlock(&ce->rnglock);

        pm_runtime_put(ce->dev);

err_pm:
        dma_unmap_single(ce->dev, dma_dst, todo, DMA_FROM_DEVICE);
err_dst:
        dma_unmap_single(ce->dev, dma_iv, ctx->slen, DMA_TO_DEVICE);

        if (!err) {
                memcpy(dst, d, dlen);
                memcpy(ctx->seed, d + dlen, ctx->slen);
        }
err_iv:
        kfree_sensitive(d);
err_mem:
        return err;
}