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|
/* drivers/android/ram_console.c
*
* Copyright (C) 2007-2008 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/console.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/proc_fs.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "ram_console.h"
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
#include <linux/rslib.h>
#endif
struct ram_console_buffer {
uint32_t sig;
uint32_t start;
uint32_t size;
uint8_t data[0];
};
#define RAM_CONSOLE_SIG (0x43474244) /* DBGC */
static char *ram_console_old_log;
static size_t ram_console_old_log_size;
static const char *bootinfo;
static size_t bootinfo_size;
static struct ram_console_buffer *ram_console_buffer;
static size_t ram_console_buffer_size;
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
static char *ram_console_par_buffer;
static struct rs_control *ram_console_rs_decoder;
static int ram_console_corrected_bytes;
static int ram_console_bad_blocks;
#define ECC_BLOCK_SIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_DATA_SIZE
#define ECC_SIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_ECC_SIZE
#define ECC_SYMSIZE CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE
#define ECC_POLY CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION_POLYNOMIAL
#endif
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
static void ram_console_encode_rs8(uint8_t *data, size_t len, uint8_t *ecc)
{
int i;
uint16_t par[ECC_SIZE];
/* Initialize the parity buffer */
memset(par, 0, sizeof(par));
encode_rs8(ram_console_rs_decoder, data, len, par, 0);
for (i = 0; i < ECC_SIZE; i++)
ecc[i] = par[i];
}
static int ram_console_decode_rs8(void *data, size_t len, uint8_t *ecc)
{
int i;
uint16_t par[ECC_SIZE];
for (i = 0; i < ECC_SIZE; i++)
par[i] = ecc[i];
return decode_rs8(ram_console_rs_decoder, data, par, len,
NULL, 0, NULL, 0, NULL);
}
#endif
static void ram_console_update(const char *s, unsigned int count)
{
struct ram_console_buffer *buffer = ram_console_buffer;
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
uint8_t *buffer_end = buffer->data + ram_console_buffer_size;
uint8_t *block;
uint8_t *par;
int size = ECC_BLOCK_SIZE;
#endif
memcpy(buffer->data + buffer->start, s, count);
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
block = buffer->data + (buffer->start & ~(ECC_BLOCK_SIZE - 1));
par = ram_console_par_buffer +
(buffer->start / ECC_BLOCK_SIZE) * ECC_SIZE;
do {
if (block + ECC_BLOCK_SIZE > buffer_end)
size = buffer_end - block;
ram_console_encode_rs8(block, size, par);
block += ECC_BLOCK_SIZE;
par += ECC_SIZE;
} while (block < buffer->data + buffer->start + count);
#endif
}
static void ram_console_update_header(void)
{
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
struct ram_console_buffer *buffer = ram_console_buffer;
uint8_t *par;
par = ram_console_par_buffer +
DIV_ROUND_UP(ram_console_buffer_size, ECC_BLOCK_SIZE) * ECC_SIZE;
ram_console_encode_rs8((uint8_t *)buffer, sizeof(*buffer), par);
#endif
}
static void
ram_console_write(struct console *console, const char *s, unsigned int count)
{
int rem;
struct ram_console_buffer *buffer = ram_console_buffer;
if (count > ram_console_buffer_size) {
s += count - ram_console_buffer_size;
count = ram_console_buffer_size;
}
rem = ram_console_buffer_size - buffer->start;
if (rem < count) {
ram_console_update(s, rem);
s += rem;
count -= rem;
buffer->start = 0;
buffer->size = ram_console_buffer_size;
}
ram_console_update(s, count);
buffer->start += count;
if (buffer->size < ram_console_buffer_size)
buffer->size += count;
ram_console_update_header();
}
static struct console ram_console = {
.name = "ram",
.write = ram_console_write,
.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
.index = -1,
};
void ram_console_enable_console(int enabled)
{
if (enabled)
ram_console.flags |= CON_ENABLED;
else
ram_console.flags &= ~CON_ENABLED;
}
static void __init
ram_console_save_old(struct ram_console_buffer *buffer, char *dest)
{
size_t old_log_size = buffer->size;
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
uint8_t *block;
uint8_t *par;
block = buffer->data;
par = ram_console_par_buffer;
while (block < buffer->data + buffer->size) {
int numerr;
int size = ECC_BLOCK_SIZE;
if (block + size > buffer->data + ram_console_buffer_size)
size = buffer->data + ram_console_buffer_size - block;
numerr = ram_console_decode_rs8(block, size, par);
if (numerr > 0) {
#if 0
printk(KERN_INFO "ram_console: error in block %p, %d\n",
block, numerr);
#endif
ram_console_corrected_bytes += numerr;
} else if (numerr < 0) {
#if 0
printk(KERN_INFO "ram_console: uncorrectable error in "
"block %p\n", block);
#endif
ram_console_bad_blocks++;
}
block += ECC_BLOCK_SIZE;
par += ECC_SIZE;
}
#endif
if (dest == NULL) {
dest = kmalloc(old_log_size, GFP_KERNEL);
if (dest == NULL) {
printk(KERN_ERR
"ram_console: failed to allocate buffer\n");
return;
}
}
ram_console_old_log = dest;
ram_console_old_log_size = old_log_size;
memcpy(ram_console_old_log,
&buffer->data[buffer->start], buffer->size - buffer->start);
memcpy(ram_console_old_log + buffer->size - buffer->start,
&buffer->data[0], buffer->start);
}
static int __init ram_console_init(struct ram_console_buffer *buffer,
size_t buffer_size, char *old_buf)
{
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
int numerr;
uint8_t *par;
#endif
ram_console_buffer = buffer;
ram_console_buffer_size =
buffer_size - sizeof(struct ram_console_buffer);
if (ram_console_buffer_size > buffer_size) {
pr_err("ram_console: buffer %p, invalid size %zu, "
"datasize %zu\n", buffer, buffer_size,
ram_console_buffer_size);
return 0;
}
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
ram_console_buffer_size -= (DIV_ROUND_UP(ram_console_buffer_size,
ECC_BLOCK_SIZE) + 1) * ECC_SIZE;
if (ram_console_buffer_size > buffer_size) {
pr_err("ram_console: buffer %p, invalid size %zu, "
"non-ecc datasize %zu\n",
buffer, buffer_size, ram_console_buffer_size);
return 0;
}
ram_console_par_buffer = buffer->data + ram_console_buffer_size;
/* first consecutive root is 0
* primitive element to generate roots = 1
*/
ram_console_rs_decoder = init_rs(ECC_SYMSIZE, ECC_POLY, 0, 1, ECC_SIZE);
if (ram_console_rs_decoder == NULL) {
printk(KERN_INFO "ram_console: init_rs failed\n");
return 0;
}
ram_console_corrected_bytes = 0;
ram_console_bad_blocks = 0;
par = ram_console_par_buffer +
DIV_ROUND_UP(ram_console_buffer_size, ECC_BLOCK_SIZE) * ECC_SIZE;
numerr = ram_console_decode_rs8(buffer, sizeof(*buffer), par);
if (numerr > 0) {
printk(KERN_INFO "ram_console: error in header, %d\n", numerr);
ram_console_corrected_bytes += numerr;
} else if (numerr < 0) {
printk(KERN_INFO
"ram_console: uncorrectable error in header\n");
ram_console_bad_blocks++;
}
#endif
if (buffer->sig == RAM_CONSOLE_SIG) {
if (buffer->size > ram_console_buffer_size
|| buffer->start > buffer->size)
printk(KERN_INFO "ram_console: found existing invalid "
"buffer, size %d, start %d\n",
buffer->size, buffer->start);
else {
printk(KERN_INFO "ram_console: found existing buffer, "
"size %d, start %d\n",
buffer->size, buffer->start);
ram_console_save_old(buffer, old_buf);
}
} else {
printk(KERN_INFO "ram_console: no valid data in buffer "
"(sig = 0x%08x)\n", buffer->sig);
}
buffer->sig = RAM_CONSOLE_SIG;
buffer->start = 0;
buffer->size = 0;
register_console(&ram_console);
return 0;
}
static ssize_t ram_console_ecc_string(char *str, size_t len)
{
#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
ssize_t ret;
if (ram_console_corrected_bytes || ram_console_bad_blocks)
ret = snprintf(str, len, ""
"\n%d Corrected bytes, %d unrecoverable blocks\n",
ram_console_corrected_bytes, ram_console_bad_blocks);
else
ret = snprintf(str, len, "\nNo errors detected\n");
return ret;
#else
return 0;
#endif
}
static int ram_console_driver_probe(struct platform_device *pdev)
{
struct resource *res = pdev->resource;
size_t start;
size_t buffer_size;
void *buffer;
struct ram_console_platform_data *pdata = pdev->dev.platform_data;
if (res == NULL || pdev->num_resources != 1 ||
!(res->flags & IORESOURCE_MEM)) {
printk(KERN_ERR "ram_console: invalid resource, %p %d flags "
"%lx\n", res, pdev->num_resources, res ? res->flags : 0);
return -ENXIO;
}
buffer_size = resource_size(res);
start = res->start;
printk(KERN_INFO "ram_console: got buffer at %zx, size %zx\n",
start, buffer_size);
buffer = ioremap(res->start, buffer_size);
if (buffer == NULL) {
printk(KERN_ERR "ram_console: failed to map memory\n");
return -ENOMEM;
}
if (pdata) {
bootinfo = kstrdup(pdata->bootinfo, GFP_KERNEL);
if (bootinfo)
bootinfo_size = strlen(bootinfo);
}
return ram_console_init(buffer, buffer_size, NULL/* allocate */);
}
static struct platform_driver ram_console_driver = {
.probe = ram_console_driver_probe,
.driver = {
.name = "ram_console",
},
};
static int __init ram_console_module_init(void)
{
int err;
err = platform_driver_register(&ram_console_driver);
return err;
}
static ssize_t ram_console_read_old(struct file *file, char __user *buf,
size_t len, loff_t *offset)
{
loff_t pos = *offset;
ssize_t count;
char *str;
int ret;
/* Main last_kmsg log */
if (pos < ram_console_old_log_size) {
count = min(len, (size_t)(ram_console_old_log_size - pos));
if (copy_to_user(buf, ram_console_old_log + pos, count))
return -EFAULT;
goto out;
}
/* ECC correction notice */
pos -= ram_console_old_log_size;
count = ram_console_ecc_string(NULL, 0);
if (pos < count) {
str = kmalloc(count, GFP_KERNEL);
if (!str)
return -ENOMEM;
ram_console_ecc_string(str, count + 1);
count = min(len, (size_t)(count - pos));
ret = copy_to_user(buf, str + pos, count);
kfree(str);
if (ret)
return -EFAULT;
goto out;
}
/* Boot info passed through pdata */
pos -= count;
if (pos < bootinfo_size) {
count = min(len, (size_t)(bootinfo_size - pos));
if (copy_to_user(buf, bootinfo + pos, count))
return -EFAULT;
goto out;
}
/* EOF */
return 0;
out:
*offset += count;
return count;
}
static const struct file_operations ram_console_file_ops = {
.owner = THIS_MODULE,
.read = ram_console_read_old,
};
static int __init ram_console_late_init(void)
{
struct proc_dir_entry *entry;
if (ram_console_old_log == NULL)
return 0;
entry = create_proc_entry("last_kmsg", S_IFREG | S_IRUGO, NULL);
if (!entry) {
printk(KERN_ERR "ram_console: failed to create proc entry\n");
kfree(ram_console_old_log);
ram_console_old_log = NULL;
return 0;
}
entry->proc_fops = &ram_console_file_ops;
entry->size = ram_console_old_log_size;
return 0;
}
postcore_initcall(ram_console_module_init);
late_initcall(ram_console_late_init);
|