Staging: android: add ram_console driver

Doesn't quite link properly under all configurations, and it has way too
many different build options, but it's a start.

Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Brian Swetland <swetland@google.com>
Cc: Robert Love <rlove@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 454 insertions, 0 deletions

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index c8899581545e..7728b84bf07c 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -14,4 +14,62 @@ config ANDROID_LOGGER
 	tristate "Android log driver"
 	default n
 
+config ANDROID_RAM_CONSOLE
+	bool "Android RAM buffer console"
+	default n
+
+config ANDROID_RAM_CONSOLE_ENABLE_VERBOSE
+	bool "Enable verbose console messages on Android RAM console"
+	default y
+	depends on ANDROID_RAM_CONSOLE
+
+menuconfig ANDROID_RAM_CONSOLE_ERROR_CORRECTION
+	bool "Android RAM Console Enable error correction"
+	default n
+	depends on ANDROID_RAM_CONSOLE
+	select REED_SOLOMON
+	select REED_SOLOMON_ENC8
+	select REED_SOLOMON_DEC8
+
+if ANDROID_RAM_CONSOLE_ERROR_CORRECTION
+
+config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_DATA_SIZE
+	int "Android RAM Console Data data size"
+	default 128
+	help
+	  Must be a power of 2.
+
+config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_ECC_SIZE
+	int "Android RAM Console ECC size"
+	default 16
+
+config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE
+	int "Android RAM Console Symbol size"
+	default 8
+
+config ANDROID_RAM_CONSOLE_ERROR_CORRECTION_POLYNOMIAL
+	hex "Android RAM Console Polynomial"
+	default 0x19 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 4)
+	default 0x29 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 5)
+	default 0x61 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 6)
+	default 0x89 if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 7)
+	default 0x11d if (ANDROID_RAM_CONSOLE_ERROR_CORRECTION_SYMBOL_SIZE = 8)
+
+endif # ANDROID_RAM_CONSOLE_ERROR_CORRECTION
+
+config ANDROID_RAM_CONSOLE_EARLY_INIT
+	bool "Start Android RAM console early"
+	default n
+	depends on ANDROID_RAM_CONSOLE
+
+config ANDROID_RAM_CONSOLE_EARLY_ADDR
+	hex "Android RAM console virtual address"
+	default 0
+	depends on ANDROID_RAM_CONSOLE_EARLY_INIT
+
+config ANDROID_RAM_CONSOLE_EARLY_SIZE
+	hex "Android RAM console buffer size"
+	default 0
+	depends on ANDROID_RAM_CONSOLE_EARLY_INIT
+
 endmenu
diff --git a/drivers/staging/android/Makefile b/drivers/staging/android/Makefile
index b354b5d90143..357abd73142a 100644
--- a/drivers/staging/android/Makefile
+++ b/drivers/staging/android/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_ANDROID)			+= android.o
 obj-$(CONFIG_ANDROID_BINDER_IPC)	+= binder.o
 obj-$(CONFIG_ANDROID_LOGGER)		+= logger.o
+obj-$(CONFIG_ANDROID_RAM_CONSOLE)	+= ram_console.o
diff --git a/drivers/staging/android/ram_console.c b/drivers/staging/android/ram_console.c
new file mode 100644
index 000000000000..bf006857a87a
--- /dev/null
+++ b/drivers/staging/android/ram_console.c
@@ -0,0 +1,395 @@
+/* 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 <asm/io.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 */
+
+#ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
+static char __initdata
+	ram_console_old_log_init_buffer[CONFIG_ANDROID_RAM_CONSOLE_EARLY_SIZE];
+#endif
+static char *ram_console_old_log;
+static size_t ram_console_old_log_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,
+	.index	= -1,
+};
+
+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;
+	char strbuf[80];
+	int strbuf_len;
+
+	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;
+	}
+	if (ram_console_corrected_bytes || ram_console_bad_blocks)
+		strbuf_len = snprintf(strbuf, sizeof(strbuf),
+			"\n%d Corrected bytes, %d unrecoverable blocks\n",
+			ram_console_corrected_bytes, ram_console_bad_blocks);
+	else
+		strbuf_len = snprintf(strbuf, sizeof(strbuf),
+				      "\nNo errors detected\n");
+	if (strbuf_len >= sizeof(strbuf))
+		strbuf_len = sizeof(strbuf) - 1;
+	old_log_size += strbuf_len;
+#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);
+#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
+	memcpy(ram_console_old_log + old_log_size - strbuf_len,
+	       strbuf, strbuf_len);
+#endif
+}
+
+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);
+
+#ifdef CONFIG_ANDROID_RAM_CONSOLE_ERROR_CORRECTION
+	ram_console_buffer_size -= (DIV_ROUND_UP(ram_console_buffer_size,
+						ECC_BLOCK_SIZE) + 1) * ECC_SIZE;
+	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);
+#ifdef CONFIG_ANDROID_RAM_CONSOLE_ENABLE_VERBOSE
+	console_verbose();
+#endif
+	return 0;
+}
+
+#ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
+static int __init ram_console_early_init(void)
+{
+	return ram_console_init((struct ram_console_buffer *)
+		CONFIG_ANDROID_RAM_CONSOLE_EARLY_ADDR,
+		CONFIG_ANDROID_RAM_CONSOLE_EARLY_SIZE,
+		ram_console_old_log_init_buffer);
+}
+#else
+static int ram_console_driver_probe(struct platform_device *pdev)
+{
+	struct resource *res = pdev->resource;
+	size_t start;
+	size_t buffer_size;
+	void *buffer;
+
+	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 = res->end - res->start + 1;
+	start = res->start;
+	printk(KERN_INFO "ram_console: got buffer at %x, size %x\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;
+	}
+
+	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;
+}
+#endif
+
+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;
+
+	if (pos >= ram_console_old_log_size)
+		return 0;
+
+	count = min(len, (size_t)(ram_console_old_log_size - pos));
+	if (copy_to_user(buf, ram_console_old_log + pos, count))
+		return -EFAULT;
+
+	*offset += count;
+	return count;
+}
+
+static 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;
+#ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
+	ram_console_old_log = kmalloc(ram_console_old_log_size, GFP_KERNEL);
+	if (ram_console_old_log == NULL) {
+		printk(KERN_ERR
+		       "ram_console: failed to allocate buffer for old log\n");
+		ram_console_old_log_size = 0;
+		return 0;
+	}
+	memcpy(ram_console_old_log,
+	       ram_console_old_log_init_buffer, ram_console_old_log_size);
+#endif
+	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;
+}
+
+#ifdef CONFIG_ANDROID_RAM_CONSOLE_EARLY_INIT
+console_initcall(ram_console_early_init);
+#else
+module_init(ram_console_module_init);
+#endif
+late_initcall(ram_console_late_init);
+