arch/arm/mach-msm/last_radio_log.c

   1 /* arch/arm/mach-msm/last_radio_log.c
   2  *
   3  * Extract the log from a modem crash though SMEM
   4  *
   5  * Copyright (C) 2007 Google, Inc.
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/fs.h>
  21 #include <linux/proc_fs.h>
  22 #include <linux/uaccess.h>
  23
  24 #include "smd_private.h"
  25
  26 static void *radio_log_base;
  27 static size_t radio_log_size;
  28
  29 extern void *smem_item(unsigned id, unsigned *size);
  30
  31 static ssize_t last_radio_log_read(struct file *file, char __user *buf,
  32                         size_t len, loff_t *offset)
  33 {
  34         loff_t pos = *offset;
  35         ssize_t count;
  36
  37         if (pos >= radio_log_size)
  38                 return 0;
  39
  40         count = min(len, (size_t)(radio_log_size - pos));
  41         if (copy_to_user(buf, radio_log_base + pos, count)) {
  42                 pr_err("%s: copy to user failed\n", __func__);
  43                 return -EFAULT;
  44         }
  45
  46         *offset += count;
  47         return count;
  48 }
  49
  50 static struct file_operations last_radio_log_fops = {
  51         .read = last_radio_log_read,
  52         .llseek = default_llseek,
  53 };
  54
  55 void msm_init_last_radio_log(struct module *owner)
  56 {
  57         struct proc_dir_entry *entry;
  58
  59         if (last_radio_log_fops.owner) {
  60                 pr_err("%s: already claimed\n", __func__);
  61                 return;
  62         }
  63
  64         radio_log_base = smem_item(SMEM_CLKREGIM_BSP, &radio_log_size);
  65         if (!radio_log_base) {
  66                 pr_err("%s: could not retrieve SMEM_CLKREGIM_BSP\n", __func__);
  67                 return;
  68         }
  69
  70         entry = create_proc_entry("last_radio_log", S_IFREG | S_IRUGO, NULL);
  71         if (!entry) {
  72                 pr_err("%s: could not create proc entry for radio log\n",
  73                                 __func__);
  74                 return;
  75         }
  76
  77         pr_err("%s: last radio log is %d bytes long\n", __func__,
  78                 radio_log_size);
  79         last_radio_log_fops.owner = owner;
  80         entry->proc_fops = &last_radio_log_fops;
  81         entry->size = radio_log_size;
  82 }
  83 EXPORT_SYMBOL(msm_init_last_radio_log);