1/*
 2 * Copyright 2012 IBM Corporation
 3 *
 4 * Author: Ashley Lai <ashleydlai@gmail.com>
 5 *         Nayna Jain <nayna@linux.vnet.ibm.com>
 6 *
 7 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 8 *
 9 * Read the event log created by the firmware on PPC64
10 *
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; either version
14 * 2 of the License, or (at your option) any later version.
15 *
16 */
17
18#include <linux/slab.h>
19#include <linux/of.h>
20#include <linux/tpm_eventlog.h>
21
22#include "tpm.h"
23
24int tpm_read_log_of(struct tpm_chip *chip)
25{
26	struct device_node *np;
27	const u32 *sizep;
28	const u64 *basep;
29	struct tpm_bios_log *log;
30	u32 size;
31	u64 base;
32
33	log = &chip->log;
34	if (chip->dev.parent && chip->dev.parent->of_node)
35		np = chip->dev.parent->of_node;
36	else
37		return -ENODEV;
38
39	if (of_property_read_bool(np, "powered-while-suspended"))
40		chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
41
42	sizep = of_get_property(np, "linux,sml-size", NULL);
43	basep = of_get_property(np, "linux,sml-base", NULL);
44	if (sizep == NULL && basep == NULL)
45		return -ENODEV;
46	if (sizep == NULL || basep == NULL)
47		return -EIO;
48
49	/*
50	 * For both vtpm/tpm, firmware has log addr and log size in big
51	 * endian format. But in case of vtpm, there is a method called
52	 * sml-handover which is run during kernel init even before
53	 * device tree is setup. This sml-handover function takes care
54	 * of endianness and writes to sml-base and sml-size in little
55	 * endian format. For this reason, vtpm doesn't need conversion
56	 * but physical tpm needs the conversion.
57	 */
58	if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0) {
59		size = be32_to_cpup(sizep);
60		base = be64_to_cpup(basep);
61	} else {
62		size = *sizep;
63		base = *basep;
64	}
65
66	if (size == 0) {
67		dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
68		return -EIO;
69	}
70
71	log->bios_event_log = kmalloc(size, GFP_KERNEL);
72	if (!log->bios_event_log)
73		return -ENOMEM;
74
75	log->bios_event_log_end = log->bios_event_log + size;
76
77	memcpy(log->bios_event_log, __va(base), size);
78
79	if (chip->flags & TPM_CHIP_FLAG_TPM2)
80		return EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
81	return EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
82}