src/arch/aarch64/qemuloader/fwcfg.c

/*
 * Copyright 2020 The Hafnium Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "fwcfg.h"

#include <stdbool.h>
#include <stdint.h>

#include "hf/arch/std.h"

#include "hf/io.h"

#define FW_CFG_CONTROL_ERROR htobe32(1 << 0)
#define FW_CFG_CONTROL_READ htobe32(1 << 1)
#define FW_CFG_CONTROL_SKIP htobe32(1 << 2)
#define FW_CFG_CONTROL_SELECT htobe32(1 << 3)
#define FW_CFG_CONTROL_WRITE htobe32(1 << 4)

#define FW_CFG_BASE 0x09020000
#define FW_CFG_DATA8 IO8_C(FW_CFG_BASE + 0)
#define FW_CFG_DATA32 IO32_C(FW_CFG_BASE + 0)
#define FW_CFG_SELECTOR IO16_C(FW_CFG_BASE + 8)
#define FW_CFG_DMA IO64_C(FW_CFG_BASE + 16)

struct fw_cfg_dma_access {
	uint32_t control;
	uint32_t length;
	uint64_t address;
};

uint32_t fw_cfg_read_uint32(uint16_t key)
{
	io_write16(FW_CFG_SELECTOR, htobe16(key));
	return io_read32(FW_CFG_DATA32);
}

void fw_cfg_read_bytes(uint16_t key, uintptr_t destination, uint32_t length)
{
	uint8_t *dest = (uint8_t *)destination;
	size_t i;

	io_write16(FW_CFG_SELECTOR, htobe16(key));
	for (i = 0; i < length; ++i) {
		dest[i] = io_read8(FW_CFG_DATA8);
	}
}

bool fw_cfg_read_dma(uint16_t key, uintptr_t destination, uint32_t length)
{
	struct fw_cfg_dma_access access = {
		.control = FW_CFG_CONTROL_READ,
		.length = htobe32(length),
		.address = htobe64(destination),
	};
	uint64_t access_address = (uint64_t)&access;

	io_write16(FW_CFG_SELECTOR, htobe16(key));
	io_write64(FW_CFG_DMA, htobe64(access_address));

	return access.control != 0;
}