1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * fw_tables.c - Parsing support for ACPI and ACPI-like tables provided by
4 * platform or device firmware
6 * Copyright (C) 2001 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7 * Copyright (C) 2023 Intel Corp.
9 #include <linux/errno.h>
10 #include <linux/acpi.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/string.h>
14 #include <linux/types.h>
15 #include <linux/fw_table.h>
17 enum acpi_subtable_type
{
25 struct acpi_subtable_entry
{
26 union acpi_subtable_headers
*hdr
;
27 enum acpi_subtable_type type
;
30 static unsigned long __init_or_fwtbl_lib
31 acpi_get_entry_type(struct acpi_subtable_entry
*entry
)
33 switch (entry
->type
) {
34 case ACPI_SUBTABLE_COMMON
:
35 return entry
->hdr
->common
.type
;
36 case ACPI_SUBTABLE_HMAT
:
37 return entry
->hdr
->hmat
.type
;
38 case ACPI_SUBTABLE_PRMT
:
40 case ACPI_SUBTABLE_CEDT
:
41 return entry
->hdr
->cedt
.type
;
43 return entry
->hdr
->cdat
.type
;
48 static unsigned long __init_or_fwtbl_lib
49 acpi_get_entry_length(struct acpi_subtable_entry
*entry
)
51 switch (entry
->type
) {
52 case ACPI_SUBTABLE_COMMON
:
53 return entry
->hdr
->common
.length
;
54 case ACPI_SUBTABLE_HMAT
:
55 return entry
->hdr
->hmat
.length
;
56 case ACPI_SUBTABLE_PRMT
:
57 return entry
->hdr
->prmt
.length
;
58 case ACPI_SUBTABLE_CEDT
:
59 return entry
->hdr
->cedt
.length
;
61 __le16 length
= (__force __le16
)entry
->hdr
->cdat
.length
;
63 return le16_to_cpu(length
);
69 static unsigned long __init_or_fwtbl_lib
70 acpi_get_subtable_header_length(struct acpi_subtable_entry
*entry
)
72 switch (entry
->type
) {
73 case ACPI_SUBTABLE_COMMON
:
74 return sizeof(entry
->hdr
->common
);
75 case ACPI_SUBTABLE_HMAT
:
76 return sizeof(entry
->hdr
->hmat
);
77 case ACPI_SUBTABLE_PRMT
:
78 return sizeof(entry
->hdr
->prmt
);
79 case ACPI_SUBTABLE_CEDT
:
80 return sizeof(entry
->hdr
->cedt
);
82 return sizeof(entry
->hdr
->cdat
);
87 static enum acpi_subtable_type __init_or_fwtbl_lib
88 acpi_get_subtable_type(char *id
)
90 if (strncmp(id
, ACPI_SIG_HMAT
, 4) == 0)
91 return ACPI_SUBTABLE_HMAT
;
92 if (strncmp(id
, ACPI_SIG_PRMT
, 4) == 0)
93 return ACPI_SUBTABLE_PRMT
;
94 if (strncmp(id
, ACPI_SIG_CEDT
, 4) == 0)
95 return ACPI_SUBTABLE_CEDT
;
96 if (strncmp(id
, ACPI_SIG_CDAT
, 4) == 0)
98 return ACPI_SUBTABLE_COMMON
;
101 static unsigned long __init_or_fwtbl_lib
102 acpi_table_get_length(enum acpi_subtable_type type
,
103 union fw_table_header
*header
)
105 if (type
== CDAT_SUBTABLE
) {
106 __le32 length
= (__force __le32
)header
->cdat
.length
;
108 return le32_to_cpu(length
);
111 return header
->acpi
.length
;
114 static __init_or_fwtbl_lib
int call_handler(struct acpi_subtable_proc
*proc
,
115 union acpi_subtable_headers
*hdr
,
119 return proc
->handler(hdr
, end
);
120 if (proc
->handler_arg
)
121 return proc
->handler_arg(hdr
, proc
->arg
, end
);
126 * acpi_parse_entries_array - for each proc_num find a suitable subtable
128 * @id: table id (for debugging purposes)
129 * @table_size: size of the root table
130 * @max_length: maximum size of the table (ignore if 0)
131 * @table_header: where does the table start?
132 * @proc: array of acpi_subtable_proc struct containing entry id
133 * and associated handler with it
134 * @proc_num: how big proc is?
135 * @max_entries: how many entries can we process?
137 * For each proc_num find a subtable with proc->id and run proc->handler
138 * on it. Assumption is that there's only single handler for particular
141 * The table_size is not the size of the complete ACPI table (the length
142 * field in the header struct), but only the size of the root table; i.e.,
143 * the offset from the very first byte of the complete ACPI table, to the
144 * first byte of the very first subtable.
146 * On success returns sum of all matching entries for all proc handlers.
147 * Otherwise, -ENODEV or -EINVAL is returned.
149 int __init_or_fwtbl_lib
150 acpi_parse_entries_array(char *id
, unsigned long table_size
,
151 union fw_table_header
*table_header
,
152 unsigned long max_length
,
153 struct acpi_subtable_proc
*proc
,
154 int proc_num
, unsigned int max_entries
)
156 unsigned long table_len
, table_end
, subtable_len
, entry_len
;
157 struct acpi_subtable_entry entry
;
158 enum acpi_subtable_type type
;
162 type
= acpi_get_subtable_type(id
);
163 table_len
= acpi_table_get_length(type
, table_header
);
164 if (max_length
&& max_length
< table_len
)
165 table_len
= max_length
;
166 table_end
= (unsigned long)table_header
+ table_len
;
168 /* Parse all entries looking for a match. */
171 entry
.hdr
= (union acpi_subtable_headers
*)
172 ((unsigned long)table_header
+ table_size
);
173 subtable_len
= acpi_get_subtable_header_length(&entry
);
175 while (((unsigned long)entry
.hdr
) + subtable_len
< table_end
) {
176 for (i
= 0; i
< proc_num
; i
++) {
177 if (acpi_get_entry_type(&entry
) != proc
[i
].id
)
180 if (!max_entries
|| count
< max_entries
)
181 if (call_handler(&proc
[i
], entry
.hdr
, table_end
))
190 * If entry->length is 0, break from this loop to avoid
193 entry_len
= acpi_get_entry_length(&entry
);
194 if (entry_len
== 0) {
195 pr_err("[%4.4s:0x%02x] Invalid zero length\n", id
, proc
->id
);
199 entry
.hdr
= (union acpi_subtable_headers
*)
200 ((unsigned long)entry
.hdr
+ entry_len
);
203 if (max_entries
&& count
> max_entries
) {
204 pr_warn("[%4.4s:0x%02x] ignored %i entries of %i found\n",
205 id
, proc
->id
, count
- max_entries
, count
);
211 int __init_or_fwtbl_lib
212 cdat_table_parse(enum acpi_cdat_type type
,
213 acpi_tbl_entry_handler_arg handler_arg
,
215 struct acpi_table_cdat
*table_header
,
216 unsigned long length
)
218 struct acpi_subtable_proc proc
= {
220 .handler_arg
= handler_arg
,
227 return acpi_parse_entries_array(ACPI_SIG_CDAT
,
228 sizeof(struct acpi_table_cdat
),
229 (union fw_table_header
*)table_header
,
230 length
, &proc
, 1, 0);
232 EXPORT_SYMBOL_FWTBL_LIB(cdat_table_parse
);