/*
 * Exynos FMP test driver
 *
 * Copyright (C) 2015 Samsung Electronics Co., Ltd.
 *
 * 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/of.h>
#include <linux/of_platform.h>
#include <linux/miscdevice.h>
#include <linux/crypto.h>
#include <linux/buffer_head.h>
#include <linux/genhd.h>
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <crypto/authenc.h>
#include <crypto/fmp.h>

#include "fmp_fips_main.h"
#include "fmp_fips_selftest.h"
#include "fmp_fips_integrity.h"
#include "fmp_test.h"

static const char pass[] = "passed";
static const char fail[] = "failed";
static const char error[] = "error";
static const char approved[] = "approved";

enum fips_state {
	FMP_FIPS_INIT_STATE,
	FMP_FIPS_PROGRESS_STATE,
	FMP_FIPS_ERR_STATE,
	FMP_FIPS_SUCCESS_STATE
};

static enum fips_state fmp_fips_state = FMP_FIPS_INIT_STATE;

bool in_fmp_fips_err(void)
{
	if (fmp_fips_state == FMP_FIPS_INIT_STATE ||
	    fmp_fips_state == FMP_FIPS_ERR_STATE)
		return true;
	return false;
}

bool in_fmp_fips_init(void)
{
	if (fmp_fips_state == FMP_FIPS_INIT_STATE)
		return true;
	return false;
}

static void set_fmp_fips_state(uint32_t val)
{
	fmp_fips_state = val;
}

static ssize_t fmp_fips_status_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct exynos_fmp *fmp = dev_get_drvdata(dev);

	return snprintf(buf, sizeof(pass), "%s\n", fmp->result.overall ? pass : fail);
}

static ssize_t aes_xts_status_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct exynos_fmp *fmp = dev_get_drvdata(dev);

	return snprintf(buf, sizeof(pass), "%s\n", fmp->result.aes_xts ? pass : fail);
}

static ssize_t sha256_status_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct exynos_fmp *fmp = dev_get_drvdata(dev);

	return snprintf(buf, sizeof(pass), "%s\n", fmp->result.sha256 ? pass : fail);
}

static ssize_t hmac_status_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct exynos_fmp *fmp = dev_get_drvdata(dev);

	return snprintf(buf, sizeof(pass), "%s\n", fmp->result.hmac ? pass : fail);
}

static ssize_t integrity_status_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct exynos_fmp *fmp = dev_get_drvdata(dev);

	return snprintf(buf, sizeof(pass), "%s\n", fmp->result.integrity ? pass : fail);
}

static ssize_t fmp_fips_err_show(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	if (in_fmp_fips_err())
		return snprintf(buf, sizeof(error), "%s\n", error);

	return snprintf(buf, sizeof(approved), "%s\n", approved);
}

static ssize_t fmp_fips_run_store(struct device *dev, struct device_attribute *attr,
			 const char *buf, size_t count)
{
	static bool run;

	if (!run) {
		struct exynos_fmp *fmp = dev_get_drvdata(dev);
		exynos_fmp_fips_test(fmp);
		run = 1;
	}
	return count;
}

static DEVICE_ATTR_RO(fmp_fips_status);
static DEVICE_ATTR_RO(aes_xts_status);
static DEVICE_ATTR_RO(sha256_status);
static DEVICE_ATTR_RO(hmac_status);
static DEVICE_ATTR_RO(integrity_status);
static DEVICE_ATTR_RO(fmp_fips_err);
static DEVICE_ATTR_WO(fmp_fips_run);

static struct attribute *fmp_fips_attr[] = {
	&dev_attr_fmp_fips_status.attr,
	&dev_attr_aes_xts_status.attr,
	&dev_attr_sha256_status.attr,
	&dev_attr_hmac_status.attr,
	&dev_attr_integrity_status.attr,
	&dev_attr_fmp_fips_err.attr,
	&dev_attr_fmp_fips_run.attr,
	NULL,
};

static struct attribute_group fmp_fips_attr_group = {
	.name	= "fmp-fips",
	.attrs	= fmp_fips_attr,
};

int exynos_fmp_fips_register(struct exynos_fmp *fmp)
{
	int ret;

	if (!fmp || !fmp->dev) {
		pr_err("%s: Invalid exynos fmp dev\n", __func__);
		goto err;
	}

	set_fmp_fips_state(FMP_FIPS_INIT_STATE);

	ret = sysfs_create_group(&fmp->dev->kobj, &fmp_fips_attr_group);
	if (ret) {
		dev_err(fmp->dev, "%s: Fail to create sysfs. ret(%d)\n",
				__func__, ret);
		goto err;
	}

	dev_info(fmp->dev, "%s: FMP register misc device. ret(%d)\n",
			__func__, ret);
	return 0;

err:
	return -EINVAL;
}

void exynos_fmp_fips_test(struct exynos_fmp *fmp)
{
	exynos_fmp_fips_init(fmp);
}
EXPORT_SYMBOL(exynos_fmp_fips_test);

int exynos_fmp_fips_init(struct exynos_fmp *fmp)
{
	int ret = 0;
#ifndef CONFIG_KEYS_IN_PRDT
	unsigned long smc_ret = 0;
	uint64_t *kwmode;
	dma_addr_t kwmode_pa;
#endif
	if (!fmp || !fmp->dev) {
		pr_err("%s: Invalid exynos fmp dev\n", __func__);
		ret = -EINVAL;
		goto out;
	}

	dev_info(fmp->dev, "%s: Started!!\n", __func__);
	set_fmp_fips_state(FMP_FIPS_PROGRESS_STATE);

	fmp->test_data = fmp_test_init(fmp);
	if (!fmp->test_data) {
		dev_err(fmp->dev,
			"%s: fails to initialize fips test.\n", __func__);
		ret = -EINVAL;
		goto out;
	}

#ifndef CONFIG_KEYS_IN_PRDT
	/* Allocate KW MODE buffer as non-cacheable */
	kwmode = dmam_alloc_coherent(fmp->dev, sizeof(uint64_t),
						&kwmode_pa, GFP_KERNEL);
	if (!kwmode) {
		dev_err(fmp->dev,
			"%s: Fail to allocate memory for fmp kwmode\n", __func__);
		ret = -ENOMEM;
		goto out;
	}

	smc_ret = exynos_fmp_get_kw_mode(kwmode_pa);
	if (smc_ret) {
		dev_err(fmp->dev, "%s: failed to get FMP KW_MODE as SECUREKEY_MODE\n", __func__);
		ret = smc_ret;
		goto dma_free;
	}

	smc_ret = exynos_fmp_set_kw_mode(DEFAULT_KWMODE);
	if (smc_ret) {
		dev_err(fmp->dev, "%s: failed to set FMP KW_MODE as SECUREKEY_MODE\n", __func__);
		ret = smc_ret;
		goto dma_free;
	}
#endif

	ret = do_fmp_selftest(fmp);
	if (ret) {
		dev_err(fmp->dev, "%s: self-tests for FMP failed\n", __func__);
		goto err_data;
	} else {
		dev_info(fmp->dev, "%s: self-tests for FMP passed\n", __func__);
	}

#ifdef CONFIG_EXYNOS_FMP_INTEGRITY_TEST
	ret = do_fmp_integrity_check(fmp);
	if (ret) {
		dev_err(fmp->dev, "%s: integrity check for FMP failed\n", __func__);
		fmp->result.integrity = 0;
		goto err_data;
	} else {
		dev_info(fmp->dev, "%s: integrity check for FMP passed\n", __func__);
		fmp->result.integrity = 1;
	}
#endif

	set_fmp_fips_state(FMP_FIPS_SUCCESS_STATE);
	fmp->result.overall = 1;
	fmp_test_exit(fmp->test_data);
	ret = 0;
#ifndef CONFIG_KEYS_IN_PRDT
	goto recover_kwmode;
#else
	goto out;
#endif

err_data:
#if defined(CONFIG_NODE_FOR_SELFTEST_FAIL)
	set_fmp_fips_state(FMP_FIPS_ERR_STATE);
	fmp->result.overall = 0;
	fmp_test_exit(fmp->test_data);
	ret = 0;
#ifndef CONFIG_KEYS_IN_PRDT
	goto recover_kwmode;
#else
	goto out;
#endif

#else
	panic("%s: Panic due to FMP self test for FIPS KAT", __func__);
#endif
#ifndef CONFIG_KEYS_IN_PRDT
recover_kwmode:
	/* Revocer KW MODE to original state */
	smc_ret = exynos_fmp_set_kw_mode(*kwmode);
	if (smc_ret) {
		dev_err(fmp->dev, "%s: failed to recover FMP KW_MODE to original state\n", __func__);
		ret = smc_ret;
	}

dma_free:
	dmam_free_coherent(fmp->dev, sizeof(uint64_t), kwmode, kwmode_pa);
#endif

out:
	if (ret)
		set_fmp_fips_state(FMP_FIPS_ERR_STATE);

	return ret;
}

void exynos_fmp_fips_deregister(struct exynos_fmp *fmp)
{
	sysfs_remove_group(&fmp->dev->kobj, &fmp_fips_attr_group);
}