last_radio_log.c

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/* arch/arm/mach-msm/last_radio_log.c
 *
 * Extract the log from a modem crash though SMEM
 *
 * Copyright (C) 2007 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/proc_fs.h>
#include <linux/uaccess.h>

#include "smd_private.h"

static void *radio_log_base;
static size_t radio_log_size;

extern void *smem_item(unsigned id, unsigned *size);

static ssize_t last_radio_log_read(struct file *file, char __user *buf,
            size_t len, loff_t *offset)
{
    loff_t pos = *offset;
    ssize_t count;

    if (pos >= radio_log_size)
        return 0;

    count = min(len, (size_t)(radio_log_size - pos));
    if (copy_to_user(buf, radio_log_base + pos, count)) {
        pr_err("%s: copy to user failed\n", __func__);
        return -EFAULT;
    }

    *offset += count;
    return count;
}

static struct file_operations last_radio_log_fops = {
    .read = last_radio_log_read,
    .llseek = default_llseek,
};

void msm_init_last_radio_log(struct module *owner)
{
    struct proc_dir_entry *entry;

    if (last_radio_log_fops.owner) {
        pr_err("%s: already claimed\n", __func__);
        return;
    }

    radio_log_base = smem_item(SMEM_CLKREGIM_BSP, &radio_log_size);
    if (!radio_log_base) {
        pr_err("%s: could not retrieve SMEM_CLKREGIM_BSP\n", __func__);
        return;
    }

    entry = create_proc_entry("last_radio_log", S_IFREG | S_IRUGO, NULL);
    if (!entry) {
        pr_err("%s: could not create proc entry for radio log\n",
                __func__);
        return;
    }

    pr_err("%s: last radio log is %d bytes long\n", __func__,
        radio_log_size);
    last_radio_log_fops.owner = owner;
    entry->proc_fops = &last_radio_log_fops;
    entry->size = radio_log_size;
}
EXPORT_SYMBOL(msm_init_last_radio_log);