diff options
Diffstat (limited to 'lib/fw_table.c')
| -rw-r--r-- | lib/fw_table.c | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/lib/fw_table.c b/lib/fw_table.c new file mode 100644 index 0000000000..c49a09ee38 --- /dev/null +++ b/lib/fw_table.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * fw_tables.c - Parsing support for ACPI and ACPI-like tables provided by + * platform or device firmware + * + * Copyright (C) 2001 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> + * Copyright (C) 2023 Intel Corp. + */ +#include <linux/errno.h> +#include <linux/acpi.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/types.h> + +enum acpi_subtable_type { + ACPI_SUBTABLE_COMMON, + ACPI_SUBTABLE_HMAT, + ACPI_SUBTABLE_PRMT, + ACPI_SUBTABLE_CEDT, +}; + +struct acpi_subtable_entry { + union acpi_subtable_headers *hdr; + enum acpi_subtable_type type; +}; + +static unsigned long __init_or_acpilib +acpi_get_entry_type(struct acpi_subtable_entry *entry) +{ + switch (entry->type) { + case ACPI_SUBTABLE_COMMON: + return entry->hdr->common.type; + case ACPI_SUBTABLE_HMAT: + return entry->hdr->hmat.type; + case ACPI_SUBTABLE_PRMT: + return 0; + case ACPI_SUBTABLE_CEDT: + return entry->hdr->cedt.type; + } + return 0; +} + +static unsigned long __init_or_acpilib +acpi_get_entry_length(struct acpi_subtable_entry *entry) +{ + switch (entry->type) { + case ACPI_SUBTABLE_COMMON: + return entry->hdr->common.length; + case ACPI_SUBTABLE_HMAT: + return entry->hdr->hmat.length; + case ACPI_SUBTABLE_PRMT: + return entry->hdr->prmt.length; + case ACPI_SUBTABLE_CEDT: + return entry->hdr->cedt.length; + } + return 0; +} + +static unsigned long __init_or_acpilib +acpi_get_subtable_header_length(struct acpi_subtable_entry *entry) +{ + switch (entry->type) { + case ACPI_SUBTABLE_COMMON: + return sizeof(entry->hdr->common); + case ACPI_SUBTABLE_HMAT: + return sizeof(entry->hdr->hmat); + case ACPI_SUBTABLE_PRMT: + return sizeof(entry->hdr->prmt); + case ACPI_SUBTABLE_CEDT: + return sizeof(entry->hdr->cedt); + } + return 0; +} + +static enum acpi_subtable_type __init_or_acpilib +acpi_get_subtable_type(char *id) +{ + if (strncmp(id, ACPI_SIG_HMAT, 4) == 0) + return ACPI_SUBTABLE_HMAT; + if (strncmp(id, ACPI_SIG_PRMT, 4) == 0) + return ACPI_SUBTABLE_PRMT; + if (strncmp(id, ACPI_SIG_CEDT, 4) == 0) + return ACPI_SUBTABLE_CEDT; + return ACPI_SUBTABLE_COMMON; +} + +static __init_or_acpilib int call_handler(struct acpi_subtable_proc *proc, + union acpi_subtable_headers *hdr, + unsigned long end) +{ + if (proc->handler) + return proc->handler(hdr, end); + if (proc->handler_arg) + return proc->handler_arg(hdr, proc->arg, end); + return -EINVAL; +} + +/** + * acpi_parse_entries_array - for each proc_num find a suitable subtable + * + * @id: table id (for debugging purposes) + * @table_size: size of the root table + * @table_header: where does the table start? + * @proc: array of acpi_subtable_proc struct containing entry id + * and associated handler with it + * @proc_num: how big proc is? + * @max_entries: how many entries can we process? + * + * For each proc_num find a subtable with proc->id and run proc->handler + * on it. Assumption is that there's only single handler for particular + * entry id. + * + * The table_size is not the size of the complete ACPI table (the length + * field in the header struct), but only the size of the root table; i.e., + * the offset from the very first byte of the complete ACPI table, to the + * first byte of the very first subtable. + * + * On success returns sum of all matching entries for all proc handlers. + * Otherwise, -ENODEV or -EINVAL is returned. + */ +int __init_or_acpilib +acpi_parse_entries_array(char *id, unsigned long table_size, + struct acpi_table_header *table_header, + struct acpi_subtable_proc *proc, + int proc_num, unsigned int max_entries) +{ + unsigned long table_end, subtable_len, entry_len; + struct acpi_subtable_entry entry; + int count = 0; + int i; + + table_end = (unsigned long)table_header + table_header->length; + + /* Parse all entries looking for a match. */ + + entry.type = acpi_get_subtable_type(id); + entry.hdr = (union acpi_subtable_headers *) + ((unsigned long)table_header + table_size); + subtable_len = acpi_get_subtable_header_length(&entry); + + while (((unsigned long)entry.hdr) + subtable_len < table_end) { + for (i = 0; i < proc_num; i++) { + if (acpi_get_entry_type(&entry) != proc[i].id) + continue; + + if (!max_entries || count < max_entries) + if (call_handler(&proc[i], entry.hdr, table_end)) + return -EINVAL; + + proc[i].count++; + count++; + break; + } + + /* + * If entry->length is 0, break from this loop to avoid + * infinite loop. + */ + entry_len = acpi_get_entry_length(&entry); + if (entry_len == 0) { + pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, proc->id); + return -EINVAL; + } + + entry.hdr = (union acpi_subtable_headers *) + ((unsigned long)entry.hdr + entry_len); + } + + if (max_entries && count > max_entries) { + pr_warn("[%4.4s:0x%02x] ignored %i entries of %i found\n", + id, proc->id, count - max_entries, count); + } + + return count; +} |