path: root/drivers/media/i2c/ccs/ccs-data.c

// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * CCS static data binary parser library
 *
 * Copyright 2019--2020 Intel Corporation
 */

#include <linux/device.h>
#include <linux/errno.h>
#include <linux/limits.h>
#include <linux/mm.h>
#include <linux/slab.h>

#include "ccs-data-defs.h"

struct bin_container {
	void *base;
	void *now;
	void *end;
	size_t size;
};

static void *bin_alloc(struct bin_container *bin, size_t len)
{
	void *ptr;

	len = ALIGN(len, 8);

	if (bin->end - bin->now < len)
		return NULL;

	ptr = bin->now;
	bin->now += len;

	return ptr;
}

static void bin_reserve(struct bin_container *bin, size_t len)
{
	bin->size += ALIGN(len, 8);
}

static int bin_backing_alloc(struct bin_container *bin)
{
	bin->base = bin->now = kvzalloc(bin->size, GFP_KERNEL);
	if (!bin->base)
		return -ENOMEM;

	bin->end = bin->base + bin->size;

	return 0;
}

#define is_contained(var, endp)				\
	(sizeof(*var) <= (endp) - (void *)(var))
#define has_headroom(ptr, headroom, endp)	\
	((headroom) <= (endp) - (void *)(ptr))
#define is_contained_with_headroom(var, headroom, endp)		\
	(sizeof(*var) + (headroom) <= (endp) - (void *)(var))

static int
ccs_data_parse_length_specifier(const struct __ccs_data_length_specifier *__len,
				size_t *__hlen, size_t *__plen,
				const void *endp)
{
	size_t hlen, plen;

	if (!is_contained(__len, endp))
		return -ENODATA;

	switch (__len->length >> CCS_DATA_LENGTH_SPECIFIER_SIZE_SHIFT) {
	case CCS_DATA_LENGTH_SPECIFIER_1:
		hlen = sizeof(*__len);
		plen = __len->length &
			((1 << CCS_DATA_LENGTH_SPECIFIER_SIZE_SHIFT) - 1);
		break;
	case CCS_DATA_LENGTH_SPECIFIER_2: {
		struct __ccs_data_length_specifier2 *__len2 = (void *)__len;

		if (!is_contained(__len2, endp))
			return -ENODATA;

		hlen = sizeof(*__len2);
		plen = ((size_t)
			(__len2->length[0] &
			 ((1 << CCS_DATA_LENGTH_SPECIFIER_SIZE_SHIFT) - 1))
			<< 8) + __len2->length[1];
		break;
	}
	case CCS_DATA_LENGTH_SPECIFIER_3: {
		struct __ccs_data_length_specifier3 *__len3 = (void *)__len;

		if (!is_contained(__len3, endp))
			return -ENODATA;

		hlen = sizeof(*__len3);
		plen = ((size_t)
			(__len3->length[0] &
			 ((1 << CCS_DATA_LENGTH_SPECIFIER_SIZE_SHIFT) - 1))
			<< 16) + (__len3->length[0] << 8) + __len3->length[1];
		break;
	}
	default:
		return -EINVAL;
	}

	if (!has_headroom(__len, hlen + plen, endp))
		return -ENODATA;

	*__hlen = hlen;
	*__plen = plen;

	return 0;
}

static u8
ccs_data_parse_format_version(const struct __ccs_data_block *block)
{
	return block->id >> CCS_DATA_BLOCK_HEADER_ID_VERSION_SHIFT;
}

static u8 ccs_data_parse_block_id(const struct __ccs_data_block *block,
				       bool is_first)
{
	if (!is_first)
		return block->id;

	return block->id & ((1 << CCS_DATA_BLOCK_HEADER_ID_VERSION_SHIFT) - 1);
}

static int ccs_data_parse_version(struct bin_container *bin,
				  struct ccs_data_container *ccsdata,
				  const void *payload, const void *endp)
{
	const struct __ccs_data_block_version *v = payload;
	struct ccs_data_block_version *vv;

	if (v + 1 != endp)
		return -ENODATA;

	if (!bin->base) {
		bin_reserve(bin, sizeof(*ccsdata->version));
		return 0;
	}

	ccsdata->version = bin_alloc(bin, sizeof(*ccsdata->version));
	if (!ccsdata->version)
		return -ENOMEM;

	vv = ccsdata->version;
	vv->version_major = ((u16)v->static_data_version_major[0] << 8) +
		v->static_data_version_major[1];
	vv->version_minor = ((u16)v->static_data_version_minor[0] << 8) +
		v->static_data_version_minor[1];
	vv->date_year =  ((u16)v->year[0] << 8) + v->year[1];
	vv->date_month = v->month;
	vv->date_day = v->day;

	return 0;
}

static void print_ccs_data_version(struct device *dev,
				   struct ccs_data_block_version *v)
{
	dev_dbg(dev,
		"static data version %4.4x.%4.4x, date %4.4u-%2.2u-%2.2u\n",
		v->version_major, v->version_minor,
		v->date_year, v->date_month, v->date_day);
}

static int ccs_data_block_parse_header(const struct __ccs_data_block *block,
				       bool is_first, unsigned int *__block_id,
				       const void **payload,
				       const struct __ccs_data_block **next_block,
				       const void *endp, struct device *dev,
				       bool verbose)
{
	size_t plen, hlen;
	u8 block_id;
	int rval;

	if (!is_contained(block, endp))
		return -ENODATA;

	rval = ccs_data_parse_length_specifier(&block->length, &hlen, &plen,
					       endp