1 /* drivers/android/ram_console.c
3 * Copyright (C) 2007-2008 Google, Inc.
5 * This software is licensed under the terms of the GNU General Public
6 * License version 2, as published by the Free Software Foundation, and
7 * may be copied, distributed, and modified under those terms.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
16 #include <linux/console.h>
17 #include <linux/init.h>
18 #include <linux/module.h>
19 #include <linux/platform_device.h>
20 #include <linux/proc_fs.h>
21 #include <linux/string.h>
22 #include <linux/uaccess.h>
24 #include "persistent_ram.h"
25 #include "ram_console.h"
27 static struct persistent_ram_zone *ram_console_zone;
28 static const char *bootinfo;
29 static size_t bootinfo_size;
32 ram_console_write(struct console *console, const char *s, unsigned int count)
34 struct persistent_ram_zone *prz = console->data;
35 persistent_ram_write(prz, s, count);
38 static struct console ram_console = {
40 .write = ram_console_write,
41 .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
45 void ram_console_enable_console(int enabled)
48 ram_console.flags |= CON_ENABLED;
50 ram_console.flags &= ~CON_ENABLED;
53 static int __init ram_console_probe(struct platform_device *pdev)
55 struct ram_console_platform_data *pdata = pdev->dev.platform_data;
56 struct persistent_ram_zone *prz;
58 prz = persistent_ram_init_ringbuffer(&pdev->dev, true);
64 bootinfo = kstrdup(pdata->bootinfo, GFP_KERNEL);
66 bootinfo_size = strlen(bootinfo);
69 ram_console_zone = prz;
70 ram_console.data = prz;
72 register_console(&ram_console);
77 static struct platform_driver ram_console_driver = {
79 .name = "ram_console",
83 static int __init ram_console_module_init(void)
85 return platform_driver_probe(&ram_console_driver, ram_console_probe);
88 static ssize_t ram_console_read_old(struct file *file, char __user *buf,
89 size_t len, loff_t *offset)
93 struct persistent_ram_zone *prz = ram_console_zone;
94 size_t old_log_size = persistent_ram_old_size(prz);
95 const char *old_log = persistent_ram_old(prz);
99 if (dmesg_restrict && !capable(CAP_SYSLOG))
102 /* Main last_kmsg log */
103 if (pos < old_log_size) {
104 count = min(len, (size_t)(old_log_size - pos));
105 if (copy_to_user(buf, old_log + pos, count))
110 /* ECC correction notice */
112 count = persistent_ram_ecc_string(prz, NULL, 0);
114 str = kmalloc(count, GFP_KERNEL);
117 persistent_ram_ecc_string(prz, str, count + 1);
118 count = min(len, (size_t)(count - pos));
119 ret = copy_to_user(buf, str + pos, count);
126 /* Boot info passed through pdata */
128 if (pos < bootinfo_size) {
129 count = min(len, (size_t)(bootinfo_size - pos));
130 if (copy_to_user(buf, bootinfo + pos, count))
143 static const struct file_operations ram_console_file_ops = {
144 .owner = THIS_MODULE,
145 .read = ram_console_read_old,
148 static int __init ram_console_late_init(void)
150 struct proc_dir_entry *entry;
151 struct persistent_ram_zone *prz = ram_console_zone;
156 if (persistent_ram_old_size(prz) == 0)
159 entry = create_proc_entry("last_kmsg", S_IFREG | S_IRUGO, NULL);
161 printk(KERN_ERR "ram_console: failed to create proc entry\n");
162 persistent_ram_free_old(prz);
166 entry->proc_fops = &ram_console_file_ops;
167 entry->size = persistent_ram_old_size(prz) +
168 persistent_ram_ecc_string(prz, NULL, 0) +
174 late_initcall(ram_console_late_init);
175 postcore_initcall(ram_console_module_init);