1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Write an ACPI Secondary System Descriptor Table (SSDT) table
4 *
5 * Copyright 2021 Google LLC
6 */
7
8#define LOG_CATEGORY LOGC_ACPI
9
10#include <acpi/acpi_table.h>
11#include <dm/acpi.h>
12#include <tables_csum.h>
13#include <linux/errno.h>
14#include <linux/string.h>
15
16int acpi_write_ssdt(struct acpi_ctx *ctx, const struct acpi_writer *entry)
17{
18	struct acpi_table_header *ssdt;
19	int ret;
20
21	ssdt = ctx->current;
22	memset(ssdt, '\0', sizeof(struct acpi_table_header));
23
24	acpi_fill_header(ssdt, "SSDT");
25	ssdt->revision = acpi_get_table_revision(ACPITAB_SSDT);
26	ssdt->creator_revision = 1;
27	ssdt->length = sizeof(struct acpi_table_header);
28
29	acpi_inc(ctx, sizeof(struct acpi_table_header));
30
31	ret = acpi_fill_ssdt(ctx);
32	if (ret) {
33		ctx->current = ssdt;
34		return log_msg_ret("fill", ret);
35	}
36
37	/* (Re)calculate length and checksum */
38	ssdt->length = ctx->current - (void *)ssdt;
39	ssdt->checksum = table_compute_checksum((void *)ssdt, ssdt->length);
40	log_debug("SSDT at %p, length %x\n", ssdt, ssdt->length);
41
42	/* Drop the table if it is empty */
43	if (ssdt->length == sizeof(struct acpi_table_header))
44		return log_msg_ret("fill", -ENOENT);
45	acpi_add_table(ctx, ssdt);
46
47	return 0;
48}
49ACPI_WRITER(6ssdt, "SSDT", acpi_write_ssdt, 0);
50