drivers/char/tpm/eventlog/of.c

   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 #include "common.h"
  24
  25 int tpm_read_log_of(struct tpm_chip *chip)
  26 {
  27         struct device_node *np;
  28         const u32 *sizep;
  29         const u64 *basep;
  30         struct tpm_bios_log *log;
  31         u32 size;
  32         u64 base;
  33
  34         log = &chip->log;
  35         if (chip->dev.parent && chip->dev.parent->of_node)
  36                 np = chip->dev.parent->of_node;
  37         else
  38                 return -ENODEV;
  39
  40         if (of_property_read_bool(np, "powered-while-suspended"))
  41                 chip->flags |= TPM_CHIP_FLAG_ALWAYS_POWERED;
  42
  43         sizep = of_get_property(np, "linux,sml-size", NULL);
  44         basep = of_get_property(np, "linux,sml-base", NULL);
  45         if (sizep == NULL && basep == NULL)
  46                 return -ENODEV;
  47         if (sizep == NULL || basep == NULL)
  48                 return -EIO;
  49
  50         /*
  51          * For both vtpm/tpm, firmware has log addr and log size in big
  52          * endian format. But in case of vtpm, there is a method called
  53          * sml-handover which is run during kernel init even before
  54          * device tree is setup. This sml-handover function takes care
  55          * of endianness and writes to sml-base and sml-size in little
  56          * endian format. For this reason, vtpm doesn't need conversion
  57          * but physical tpm needs the conversion.
  58          */
  59         if (of_property_match_string(np, "compatible", "IBM,vtpm") < 0) {
  60                 size = be32_to_cpup((__force __be32 *)sizep);
  61                 base = be64_to_cpup((__force __be64 *)basep);
  62         } else {
  63                 size = *sizep;
  64                 base = *basep;
  65         }
  66
  67         if (size == 0) {
  68                 dev_warn(&chip->dev, "%s: Event log area empty\n", __func__);
  69                 return -EIO;
  70         }
  71
  72         log->bios_event_log = kmemdup(__va(base), size, GFP_KERNEL);
  73         if (!log->bios_event_log)
  74                 return -ENOMEM;
  75
  76         log->bios_event_log_end = log->bios_event_log + size;
  77
  78         if (chip->flags & TPM_CHIP_FLAG_TPM2)
  79                 return EFI_TCG2_EVENT_LOG_FORMAT_TCG_2;
  80         return EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2;
  81 }