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
21 #include "tpm.h"
22 #include "tpm_eventlog.h"
23
tpm_read_log_of(struct tpm_chip * chip)24 int 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 return 0;
80 }
81