1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * A hack to create a platform device from a DMI entry. This will
4 * allow autoloading of the IPMI drive based on SMBIOS entries.
5 */
6
7#define pr_fmt(fmt) "%s" fmt, "ipmi:dmi: "
8#define dev_fmt pr_fmt
9
10#include <linux/ipmi.h>
11#include <linux/init.h>
12#include <linux/dmi.h>
13#include <linux/platform_device.h>
14#include <linux/property.h>
15#include "ipmi_dmi.h"
16#include "ipmi_plat_data.h"
17
18#define IPMI_DMI_TYPE_KCS 0x01
19#define IPMI_DMI_TYPE_SMIC 0x02
20#define IPMI_DMI_TYPE_BT 0x03
21#define IPMI_DMI_TYPE_SSIF 0x04
22
23struct ipmi_dmi_info {
24 enum si_type si_type;
25 unsigned int space; /* addr space for si, intf# for ssif */
26 unsigned long addr;
27 u8 slave_addr;
28 struct ipmi_dmi_info *next;
29};
30
31static struct ipmi_dmi_info *ipmi_dmi_infos;
32
33static int ipmi_dmi_nr __initdata;
34
35static void __init dmi_add_platform_ipmi(unsigned long base_addr,
36 unsigned int space,
37 u8 slave_addr,
38 int irq,
39 int offset,
40 int type)
41{
42 const char *name;
43 struct ipmi_dmi_info *info;
44 struct ipmi_plat_data p;
45
46 memset(&p, 0, sizeof(p));
47
48 name = "dmi-ipmi-si";
49 p.iftype = IPMI_PLAT_IF_SI;
50 switch (type) {
51 case IPMI_DMI_TYPE_SSIF:
52 name = "dmi-ipmi-ssif";
53 p.iftype = IPMI_PLAT_IF_SSIF;
54 p.type = SI_TYPE_INVALID;
55 break;
56 case IPMI_DMI_TYPE_BT:
57 p.type = SI_BT;
58 break;
59 case IPMI_DMI_TYPE_KCS:
60 p.type = SI_KCS;
61 break;
62 case IPMI_DMI_TYPE_SMIC:
63 p.type = SI_SMIC;
64 break;
65 default:
66 pr_err("Invalid IPMI type: %d\n", type);
67 return;
68 }
69
70 p.addr = base_addr;
71 p.space = space;
72 p.regspacing = offset;
73 p.irq = irq;
74 p.slave_addr = slave_addr;
75 p.addr_source = SI_SMBIOS;
76
77 info = kmalloc(sizeof(*info), GFP_KERNEL);
78 if (!info) {
79 pr_warn("Could not allocate dmi info\n");
80 } else {
81 info->si_type = p.type;
82 info->space = space;
83 info->addr = base_addr;
84 info->slave_addr = slave_addr;
85 info->next = ipmi_dmi_infos;
86 ipmi_dmi_infos = info;
87 }
88
89 if (ipmi_platform_add(name, inst: ipmi_dmi_nr, p: &p))
90 ipmi_dmi_nr++;
91}
92
93/*
94 * Look up the slave address for a given interface. This is here
95 * because ACPI doesn't have a slave address while SMBIOS does, but we
96 * prefer using ACPI so the ACPI code can use the IPMI namespace.
97 * This function allows an ACPI-specified IPMI device to look up the
98 * slave address from the DMI table.
99 */
100int ipmi_dmi_get_slave_addr(enum si_type si_type, unsigned int space,
101 unsigned long base_addr)
102{
103 struct ipmi_dmi_info *info = ipmi_dmi_infos;
104
105 while (info) {
106 if (info->si_type == si_type &&
107 info->space == space &&
108 info->addr == base_addr)
109 return info->slave_addr;
110 info = info->next;
111 }
112
113 return 0;
114}
115EXPORT_SYMBOL(ipmi_dmi_get_slave_addr);
116
117#define DMI_IPMI_MIN_LENGTH 0x10
118#define DMI_IPMI_VER2_LENGTH 0x12
119#define DMI_IPMI_TYPE 4
120#define DMI_IPMI_SLAVEADDR 6
121#define DMI_IPMI_ADDR 8
122#define DMI_IPMI_ACCESS 0x10
123#define DMI_IPMI_IRQ 0x11
124#define DMI_IPMI_IO_MASK 0xfffe
125
126static void __init dmi_decode_ipmi(const struct dmi_header *dm)
127{
128 const u8 *data = (const u8 *) dm;
129 int space = IPMI_IO_ADDR_SPACE;
130 unsigned long base_addr;
131 u8 len = dm->length;
132 u8 slave_addr;
133 int irq = 0, offset = 0;
134 int type;
135
136 if (len < DMI_IPMI_MIN_LENGTH)
137 return;
138
139 type = data[DMI_IPMI_TYPE];
140 slave_addr = data[DMI_IPMI_SLAVEADDR];
141
142 memcpy(&base_addr, data + DMI_IPMI_ADDR, sizeof(unsigned long));
143 if (!base_addr) {
144 pr_err("Base address is zero, assuming no IPMI interface\n");
145 return;
146 }
147 if (len >= DMI_IPMI_VER2_LENGTH) {
148 if (type == IPMI_DMI_TYPE_SSIF) {
149 space = 0; /* Match I2C interface 0. */
150 base_addr = data[DMI_IPMI_ADDR] >> 1;
151 if (base_addr == 0) {
152 /*
153 * Some broken systems put the I2C address in
154 * the slave address field. We try to
155 * accommodate them here.
156 */
157 base_addr = data[DMI_IPMI_SLAVEADDR] >> 1;
158 slave_addr = 0;
159 }
160 } else {
161 if (base_addr & 1) {
162 /* I/O */
163 base_addr &= DMI_IPMI_IO_MASK;
164 } else {
165 /* Memory */
166 space = IPMI_MEM_ADDR_SPACE;
167 }
168
169 /*
170 * If bit 4 of byte 0x10 is set, then the lsb
171 * for the address is odd.
172 */
173 base_addr |= (data[DMI_IPMI_ACCESS] >> 4) & 1;
174
175 irq = data[DMI_IPMI_IRQ];
176
177 /*
178 * The top two bits of byte 0x10 hold the
179 * register spacing.
180 */
181 switch ((data[DMI_IPMI_ACCESS] >> 6) & 3) {
182 case 0: /* Byte boundaries */
183 offset = 1;
184 break;
185 case 1: /* 32-bit boundaries */
186 offset = 4;
187 break;
188 case 2: /* 16-byte boundaries */
189 offset = 16;
190 break;
191 default:
192 pr_err("Invalid offset: 0\n");
193 return;
194 }
195 }
196 } else {
197 /* Old DMI spec. */
198 /*
199 * Note that technically, the lower bit of the base
200 * address should be 1 if the address is I/O and 0 if
201 * the address is in memory. So many systems get that
202 * wrong (and all that I have seen are I/O) so we just
203 * ignore that bit and assume I/O. Systems that use
204 * memory should use the newer spec, anyway.
205 */
206 base_addr = base_addr & DMI_IPMI_IO_MASK;
207 offset = 1;
208 }
209
210 dmi_add_platform_ipmi(base_addr, space, slave_addr, irq,
211 offset, type);
212}
213
214static int __init scan_for_dmi_ipmi(void)
215{
216 const struct dmi_device *dev = NULL;
217
218 while ((dev = dmi_find_device(type: DMI_DEV_TYPE_IPMI, NULL, from: dev)))
219 dmi_decode_ipmi(dm: (const struct dmi_header *) dev->device_data);
220
221 return 0;
222}
223subsys_initcall(scan_for_dmi_ipmi);
224

source code of linux/drivers/char/ipmi/ipmi_dmi.c