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-rw-r--r--lib/fw_table.c176
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;
+}