subsys/mem_mgmt/mem_attr.c

/*
 * Copyright (c) 2023 Carlo Caione, <ccaione@baylibre.com>
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/kernel.h>
#include <zephyr/mem_mgmt/mem_attr.h>

#define _BUILD_MEM_ATTR_REGION(node_id)					\
	{								\
		.dt_name = DT_NODE_FULL_NAME(node_id),			\
		.dt_addr = DT_REG_ADDR(node_id),			\
		.dt_size = DT_REG_SIZE(node_id),			\
		.dt_attr = DT_PROP(node_id, zephyr_memory_attr),	\
	},

static const struct mem_attr_region_t mem_attr_region[] = {
	DT_MEMORY_ATTR_FOREACH_STATUS_OKAY_NODE(_BUILD_MEM_ATTR_REGION)
};

size_t mem_attr_get_regions(const struct mem_attr_region_t **region)
{
	*region = mem_attr_region;

	return ARRAY_SIZE(mem_attr_region);
}

int mem_attr_check_buf(void *v_addr, size_t size, uint32_t attr)
{
	uintptr_t addr = (uintptr_t) v_addr;

	/*
	 * If MMU is enabled the address of the buffer is a virtual address
	 * while the addresses in the DT are physical addresses. Given that we
	 * have no way of knowing whether a mapping exists, we simply bail out.
	 */
	if (IS_ENABLED(CONFIG_MMU)) {
		return -ENOSYS;
	}

	if (size == 0) {
		return -ENOTSUP;
	}

	for (size_t idx = 0; idx < ARRAY_SIZE(mem_attr_region); idx++) {
		const struct mem_attr_region_t *region = &mem_attr_region[idx];
		size_t region_end = region->dt_addr + region->dt_size;

		/* Check if the buffer is in the region */
		if ((addr >= region->dt_addr) && (addr < region_end)) {
			/* Check if the buffer is entirely contained in the region */
			if ((addr + size) <= region_end) {
				/* check if the attribute is correct */
				return (region->dt_attr & attr) == attr ? 0 : -EINVAL;
			}
			return -ENOSPC;
		}
	}
	return -ENOBUFS;
}