drivers/char/tpm/tpm_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
  21 #include "tpm.h"
  22 #include "tpm_eventlog.h"
  23
  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 }