drivers/mm/mm_drv_ti_rat.c

/*
 * Copyright (c) 2023 Texas Instruments Incorporated
 * Copyright (c) 2023 L Lakshmanan
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/**
 * @file
 * @brief Driver handling Region based Address Translation (RAT)
 * related functions
 *
 * RAT is a module that is used by certain Texas Instruments SoCs
 * to allow some cores with a 32 bit address space to access
 * the full 48 bit SoC address space. This is required for the
 * core to be able to use peripherals.
 *
 * The driver uses the sys_mm_drv_page_phys_get() API to access
 * the address space.
 */

#include <zephyr/kernel.h>
#include <zephyr/drivers/mm/rat.h>
#include <zephyr/drivers/mm/system_mm.h>
#include <zephyr/sys/__assert.h>

static struct address_trans_params translate_config;

/**
 * @brief Set registers for the address regions being used
 *
 * @param addr_translate_config Pointer to config struct for the RAT module
 * @param region_num Number of regions being initialised
 * @param enable Region status
 */

static void address_trans_set_region(struct address_trans_params *addr_translate_config,
			uint16_t region_num, uint32_t enable)
{
	uint32_t rat_base_addr = addr_translate_config->rat_base_addr;
	uint64_t system_addr = addr_translate_config->region_config[region_num].system_addr;
	uint32_t local_addr = addr_translate_config->region_config[region_num].local_addr;
	uint32_t size = addr_translate_config->region_config[region_num].size;
	uint32_t system_addrL, system_addrH;

	if (size > address_trans_region_size_4G) {
		size = address_trans_region_size_4G;
	}
	system_addrL = (uint32_t)(system_addr & ~((uint32_t)((BIT64_MASK(size)))));
	system_addrH = (uint32_t)((system_addr >> 32) & 0xFFFF);
	local_addr = local_addr & ~((uint32_t)(BIT64_MASK(size)));

	sys_write32(0, RAT_CTRL(rat_base_addr, region_num));
	sys_write32(local_addr, RAT_BASE(rat_base_addr, region_num));
	sys_write32(system_addrL, RAT_TRANS_L(rat_base_addr, region_num));
	sys_write32(system_addrH, RAT_TRANS_H(rat_base_addr, region_num));
	sys_write32(RAT_CTRL_W(enable, size), RAT_CTRL(rat_base_addr, region_num));
}

static void address_trans_init(struct address_trans_params *params)
{
	uint32_t i;

	if (params != NULL) {
		translate_config = *params;
	}

	__ASSERT(translate_config.num_regions < ADDR_TRANSLATE_MAX_REGIONS,
		 "Exceeding maximum number of regions");

	for (i = 0; i < translate_config.num_regions; i++) {
		__ASSERT(translate_config.rat_base_addr != 0, "RAT base address cannot be 0");
		__ASSERT(translate_config.region_config != NULL,
			 "RAT region config cannot be NULL");

		/* enable regions setup by user */
		address_trans_set_region(&translate_config, i, 1);
	}
}

/**
 * @brief Initialise RAT module
 *
 * @param region_config Pointer to config struct for the regions
 * @param rat_base_addr Base address for the RAT module
 * @param translate_regions Number of regions being initialised
 */

void sys_mm_drv_ti_rat_init(void *region_config, uint64_t rat_base_addr, uint8_t translate_regions)
{
	translate_config.num_regions = translate_regions;
	translate_config.rat_base_addr = rat_base_addr;
	translate_config.region_config = (struct address_trans_region_config *)region_config;

	address_trans_init(&translate_config);
}

int sys_mm_drv_page_phys_get(void *virt, uintptr_t *phys)
{
	if (virt == NULL) {
		return -EINVAL;
	}
	uintptr_t pa = (uintptr_t) virt;
	uintptr_t *va = phys;

	uint32_t found, regionId;

	__ASSERT(translate_config.num_regions < ADDR_TRANSLATE_MAX_REGIONS,
		 "Exceeding maximum number of regions");

	found = 0;

	for (regionId = 0; regionId < translate_config.num_regions; regionId++) {
		uint64_t start_addr, end_addr;
		uint32_t size_mask;

		size_mask =
			((uint32_t)((BIT64_MASK(translate_config.region_config[regionId].size))));

		start_addr = translate_config.region_config[regionId].system_addr;

		end_addr = start_addr + size_mask;

		if (pa >= start_addr && pa <= end_addr) {
			found = 1;
			break;
		}
	}
	if (found) {
		/* translate input address to output address */
		uint32_t offset =
			pa - translate_config.region_config[regionId].system_addr;

		*va = (translate_config.region_config[regionId].local_addr + offset);
	} else {
		/* no mapping found, set output = input with 32b truncation */
		*va = pa;
	}

	if (va == NULL) {
		return -EFAULT;
	}
	return 0;
}