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 ram_console_driver_probe(struct platform_device *pdev)
55 struct resource *res = pdev->resource;
59 struct ram_console_platform_data *pdata = pdev->dev.platform_data;
62 if (res == NULL || pdev->num_resources != 1 ||
63 !(res->flags & IORESOURCE_MEM)) {
64 printk(KERN_ERR "ram_console: invalid resource, %p %d flags "
65 "%lx\n", res, pdev->num_resources, res ? res->flags : 0);
68 buffer_size = resource_size(res);
70 printk(KERN_INFO "ram_console: got buffer at %zx, size %zx\n",
72 buffer = ioremap(res->start, buffer_size);
74 printk(KERN_ERR "ram_console: failed to map memory\n");
78 ret = persistent_ram_init_ringbuffer(&ram_console_zone, buffer,
84 bootinfo = kstrdup(pdata->bootinfo, GFP_KERNEL);
86 bootinfo_size = strlen(bootinfo);
89 ram_console.data = &ram_console_zone;
91 register_console(&ram_console);
99 static struct platform_driver ram_console_driver = {
100 .probe = ram_console_driver_probe,
102 .name = "ram_console",
106 static int __init ram_console_module_init(void)
109 err = platform_driver_register(&ram_console_driver);
113 static ssize_t ram_console_read_old(struct file *file, char __user *buf,
114 size_t len, loff_t *offset)
116 loff_t pos = *offset;
118 struct persistent_ram_zone *prz = &ram_console_zone;
119 size_t old_log_size = persistent_ram_old_size(prz);
120 const char *old_log = persistent_ram_old(prz);
124 /* Main last_kmsg log */
125 if (pos < old_log_size) {
126 count = min(len, (size_t)(old_log_size - pos));
127 if (copy_to_user(buf, old_log + pos, count))
132 /* ECC correction notice */
134 count = persistent_ram_ecc_string(prz, NULL, 0);
136 str = kmalloc(count, GFP_KERNEL);
139 persistent_ram_ecc_string(prz, str, count + 1);
140 count = min(len, (size_t)(count - pos));
141 ret = copy_to_user(buf, str + pos, count);
148 /* Boot info passed through pdata */
150 if (pos < bootinfo_size) {
151 count = min(len, (size_t)(bootinfo_size - pos));
152 if (copy_to_user(buf, bootinfo + pos, count))
165 static const struct file_operations ram_console_file_ops = {
166 .owner = THIS_MODULE,
167 .read = ram_console_read_old,
170 static int __init ram_console_late_init(void)
172 struct proc_dir_entry *entry;
173 struct persistent_ram_zone *prz = &ram_console_zone;
175 if (persistent_ram_old_size(prz) == 0)
178 entry = create_proc_entry("last_kmsg", S_IFREG | S_IRUGO, NULL);
180 printk(KERN_ERR "ram_console: failed to create proc entry\n");
181 persistent_ram_free_old(prz);
185 entry->proc_fops = &ram_console_file_ops;
186 entry->size = persistent_ram_old_size(prz) +
187 persistent_ram_ecc_string(prz, NULL, 0) +
193 late_initcall(ram_console_late_init);
194 postcore_initcall(ram_console_module_init);