path: root/drivers/crypto/intel/keembay/keembay-ocs-hcu-core.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Intel Keem Bay OCS HCU Crypto Driver.
 *
 * Copyright (C) 2018-2020 Intel Corporation
 */

#include <crypto/engine.h>
#include <crypto/hmac.h>
#include <crypto/internal/hash.h>
#include <crypto/scatterwalk.h>
#include <crypto/sha2.h>
#include <crypto/sm3.h>
#include <linux/completion.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/string.h>

#include "ocs-hcu.h"

#define DRV_NAME	"keembay-ocs-hcu"

/* Flag marking a final request. */
#define REQ_FINAL			BIT(0)
/* Flag marking a HMAC request. */
#define REQ_FLAGS_HMAC			BIT(1)
/* Flag set when HW HMAC is being used. */
#define REQ_FLAGS_HMAC_HW		BIT(2)
/* Flag set when SW HMAC is being used. */
#define REQ_FLAGS_HMAC_SW		BIT(3)

/**
 * struct ocs_hcu_ctx: OCS HCU Transform context.
 * @hcu_dev:	 The OCS HCU device used by the transformation.
 * @key:	 The key (used only for HMAC transformations).
 * @key_len:	 The length of the key.
 * @is_sm3_tfm:  Whether or not this is an SM3 transformation.
 * @is_hmac_tfm: Whether or not this is a HMAC transformation.
 */
struct ocs_hcu_ctx {
	struct ocs_hcu_dev *hcu_dev;
	u8 key[SHA512_BLOCK_SIZE];
	size_t key_len;
	bool is_sm3_tfm;
	bool is_hmac_tfm;
};

/**
 * struct ocs_hcu_rctx - Context for the request.
 * @hcu_dev:	    OCS HCU device to be used to service the request.
 * @flags:	    Flags tracking request status.
 * @algo:	    Algorithm to use for the request.
 * @blk_sz:	    Block size of the transformation / request.
 * @dig_sz:	    Digest size of the transformation / request.
 * @dma_list:	    OCS DMA linked list.
 * @hash_ctx:	    OCS HCU hashing context.
 * @buffer:	    Buffer to store: partial block of data and SW HMAC
 *		    artifacts (ipad, opad, etc.).
 * @buf_cnt:	    Number of bytes currently stored in the buffer.
 * @buf_dma_addr:   The DMA address of @buffer (when mapped).
 * @buf_dma_count:  The number of bytes in @buffer currently DMA-mapped.
 * @sg:		    Head of the scatterlist entries containing data.
 * @sg_data_total:  Total data in the SG list at any time.
 * @sg_data_offset: Offset into the data of the current individual SG node.
 * @sg_dma_nents:   Number of sg entries mapped in dma_list.
 */
struct ocs_hcu_rctx {
	struct ocs_hcu_dev	*hcu_dev;
	u32			flags;
	enum ocs_hcu_algo	algo;
	size_t			blk_sz;
	size_t			dig_sz;
	struct ocs_hcu_dma_list	*dma_list;
	struct ocs_hcu_hash_ctx	hash_ctx;
	/*
	 * Buffer is double the block size because we need space for SW HMAC
	 * artifacts, i.e:
	 * - ipad (1 block) + a possible partial block of data.
	 * - opad (1 block) + digest of H(k ^ ipad || m)
	 */
	u8			buffer[2 * SHA512_BLOCK_SIZE];
	size_t			buf_cnt;
	dma_addr_t		buf_dma_addr;
	size_t			buf_dma_count;
	struct scatterlist	*sg;
	unsigned int		sg_data_total;
	unsigned int		sg_data_offset;
	unsigned int		sg_dma_nents;
};

/**
 * struct ocs_hcu_drv - Driver data
 * @dev_list:	The list of HCU devices.
 * @lock:	The lock protecting dev_list.
 */
struct ocs_hcu_drv {
	struct list_head dev_list;
	spinlock_t lock; /* Protects dev_list. */
};

static struct ocs_hcu_drv ocs_hcu = {
	.dev_list = LIST_HEAD_INIT(ocs_hcu.dev_list),
	.lock = __SPIN_LOCK_UNLOCKED(ocs_hcu.lock),
};

/*
 * Return the total amount of data in the request; that is: the data in the
 * request buffer + the data in the sg list.
 */
static inline unsigned int kmb_get_total_data(struct ocs_hcu_rctx *rctx)
{
	return rctx->sg_data_total + rctx->buf_cnt;
}

/* Move remaining content of scatter-gather list to context buffer. */
static int flush_sg_to_ocs_buffer(struct ocs_hcu_rctx *rctx)
{
	size_t count;

	if (rctx->sg_data_total > (sizeof(rctx->buffer) - rctx->buf_cnt)) {
		WARN(1, "%s: sg data does not fit in buffer\n", __func__);
		return -EINVAL;
	}

	while (rctx->sg_data_total) {
		if (!rctx->sg) {
			WARN(1, "%s: unexpected NULL sg\n", __func__);
			return -EINVAL;
		}
		/*
		 * If current sg has been fully processed, skip to the next
		 * one.
		 */
		if (rctx->sg_data_offset == rctx->sg->length) {
			rctx->sg = sg_next(rctx->sg</