1/*
2 * Common Option ROM Functions for fw_cfg
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see <http://www.gnu.org/licenses/>.
16 *
17 * Copyright (c) 2015-2019 Red Hat Inc.
18 * Authors:
19 * Marc Marí <marc.mari.barcelo@gmail.com>
20 * Richard W.M. Jones <rjones@redhat.com>
21 * Stefano Garzarella <sgarzare@redhat.com>
22 */
23
24#ifndef OPTROM_FW_CFG_H
25#define OPTROM_FW_CFG_H
26
27#include "../../include/standard-headers/linux/qemu_fw_cfg.h"
28
29#define BIOS_CFG_IOPORT_CFG 0x510
30#define BIOS_CFG_IOPORT_DATA 0x511
31#define BIOS_CFG_DMA_ADDR_HIGH 0x514
32#define BIOS_CFG_DMA_ADDR_LOW 0x518
33
34static __attribute__((unused))
35void bios_cfg_select(uint16_t key)
36{
37 outw(key, BIOS_CFG_IOPORT_CFG);
38}
39
40static __attribute__((unused))
41void bios_cfg_read_entry_io(void *buf, uint16_t entry, uint32_t len)
42{
43 bios_cfg_select(entry);
44 insb(BIOS_CFG_IOPORT_DATA, buf, len);
45}
46
47/*
48 * clang is happy to inline this function, and bloats the
49 * ROM.
50 */
51static __attribute__((__noinline__)) __attribute__((unused))
52void bios_cfg_read_entry_dma(void *buf, uint16_t entry, uint32_t len)
53{
54 struct fw_cfg_dma_access access;
55 uint32_t control = (entry << 16) | FW_CFG_DMA_CTL_SELECT
56 | FW_CFG_DMA_CTL_READ;
57
58 access.address = cpu_to_be64((uint64_t)(uint32_t)buf);
59 access.length = cpu_to_be32(len);
60 access.control = cpu_to_be32(control);
61
62 barrier();
63
64 outl(cpu_to_be32((uint32_t)&access), BIOS_CFG_DMA_ADDR_LOW);
65
66 while (be32_to_cpu(access.control) & ~FW_CFG_DMA_CTL_ERROR) {
67 barrier();
68 }
69}
70
71static __attribute__((unused))
72void bios_cfg_read_entry(void *buf, uint16_t entry, uint32_t len,
73 uint32_t version)
74{
75 if (version & FW_CFG_VERSION_DMA) {
76 bios_cfg_read_entry_dma(buf, entry, len);
77 } else {
78 bios_cfg_read_entry_io(buf, entry, len);
79 }
80}
81
82static __attribute__((unused))
83uint32_t bios_cfg_version(void)
84{
85 uint32_t version;
86
87 bios_cfg_read_entry_io(&version, FW_CFG_ID, sizeof(version));
88
89 return version;
90}
91
92#endif /* OPTROM_FW_CFG_H */
93