[09/11] persistent_ram: Move to fs/pstore/ram_core.c

diff --git a/drivers/staging/android/Kconfig b/drivers/staging/android/Kconfig
index 42f0133..4bfcceb 100644
--- a/drivers/staging/android/Kconfig
+++ b/drivers/staging/android/Kconfig
@@ -25,17 +25,9 @@  config ANDROID_LOGGER
 	tristate "Android log driver"
 	default n
 
-config ANDROID_PERSISTENT_RAM
-	bool
-	depends on HAVE_MEMBLOCK
-	select REED_SOLOMON
-	select REED_SOLOMON_ENC8
-	select REED_SOLOMON_DEC8
-
 config ANDROID_RAM_CONSOLE
 	bool "Android RAM buffer console"
-	depends on !S390 && !UML && HAVE_MEMBLOCK
-	select ANDROID_PERSISTENT_RAM
+	depends on !S390 && !UML && HAVE_MEMBLOCK && PSTORE_RAM
 	default n
 
 config ANDROID_TIMED_OUTPUT
diff --git a/drivers/staging/android/persistent_ram.c b/drivers/staging/android/persistent_ram.c
deleted file mode 100644
index 63481da..0000000
--- a/drivers/staging/android/persistent_ram.c
+++ /dev/null
@@ -1,530 +0,0 @@ 
-/*
- * Copyright (C) 2012 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/device.h>
-#include <linux/err.h>
-#include <linux/errno.h>
-#include <linux/kernel.h>
-#include <linux/init.h>
-#include <linux/io.h>
-#include <linux/list.h>
-#include <linux/memblock.h>
-#include <linux/rslib.h>
-#include <linux/slab.h>
-#include <linux/vmalloc.h>
-#include <asm/page.h>
-#include "persistent_ram.h"
-
-struct persistent_ram_buffer {
-	uint32_t    sig;
-	atomic_t    start;
-	atomic_t    size;
-	uint8_t     data[0];
-};
-
-#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
-
-static __initdata LIST_HEAD(persistent_ram_list);
-
-static inline size_t buffer_size(struct persistent_ram_zone *prz)
-{
-	return atomic_read(&prz->buffer->size);
-}
-
-static inline size_t buffer_start(struct persistent_ram_zone *prz)
-{
-	return atomic_read(&prz->buffer->start);
-}
-
-/* increase and wrap the start pointer, returning the old value */
-static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
-{
-	int old;
-	int new;
-
-	do {
-		old = atomic_read(&prz->buffer->start);
-		new = old + a;
-		while (unlikely(new > prz->buffer_size))
-			new -= prz->buffer_size;
-	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
-
-	return old;
-}
-
-/* increase the size counter until it hits the max size */
-static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
-{
-	size_t old;
-	size_t new;
-
-	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
-		return;
-
-	do {
-		old = atomic_read(&prz->buffer->size);
-		new = old + a;
-		if (new > prz->buffer_size)
-			new = prz->buffer_size;
-	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
-}
-
-static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
-	uint8_t *data, size_t len, uint8_t *ecc)
-{
-	int i;
-	uint16_t par[prz->ecc_size];
-
-	/* Initialize the parity buffer */
-	memset(par, 0, sizeof(par));
-	encode_rs8(prz->rs_decoder, data, len, par, 0);
-	for (i = 0; i < prz->ecc_size; i++)
-		ecc[i] = par[i];
-}
-
-static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
-	void *data, size_t len, uint8_t *ecc)
-{
-	int i;
-	uint16_t par[prz->ecc_size];
-
-	for (i = 0; i < prz->ecc_size; i++)
-		par[i] = ecc[i];
-	return decode_rs8(prz->rs_decoder, data, par, len,
-				NULL, 0, NULL, 0, NULL);
-}
-
-static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
-	unsigned int start, unsigned int count)
-{
-	struct persistent_ram_buffer *buffer = prz->buffer;
-	uint8_t *buffer_end = buffer->data + prz->buffer_size;
-	uint8_t *block;
-	uint8_t *par;
-	int ecc_block_size = prz->ecc_block_size;
-	int ecc_size = prz->ecc_size;
-	int size = prz->ecc_block_size;
-
-	if (!prz->ecc)
-		return;
-
-	block = buffer->data + (start & ~(ecc_block_size - 1));
-	par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
-
-	do {
-		if (block + ecc_block_size > buffer_end)
-			size = buffer_end - block;
-		persistent_ram_encode_rs8(prz, block, size, par);
-		block += ecc_block_size;
-		par += ecc_size;
-	} while (block < buffer->data + start + count);
-}
-
-static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
-{
-	struct persistent_ram_buffer *buffer = prz->buffer;
-
-	if (!prz->ecc)
-		return;
-
-	persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
-				  prz->par_header);
-}
-
-static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
-{
-	struct persistent_ram_buffer *buffer = prz->buffer;
-	uint8_t *block;
-	uint8_t *par;
-
-	if (!prz->ecc)
-		return;
-
-	block = buffer->data;
-	par = prz->par_buffer;
-	while (block < buffer->data + buffer_size(prz)) {
-		int numerr;
-		int size = prz->ecc_block_size;
-		if (block + size > buffer->data + prz->buffer_size)
-			size = buffer->data + prz->buffer_size - block;
-		numerr = persistent_ram_decode_rs8(prz, block, size, par);
-		if (numerr > 0) {
-			pr_devel("persistent_ram: error in block %p, %d\n",
-			       block, numerr);
-			prz->corrected_bytes += numerr;
-		} else if (numerr < 0) {
-			pr_devel("persistent_ram: uncorrectable error in block %p\n",
-				block);
-			prz->bad_blocks++;
-		}
-		block += prz->ecc_block_size;
-		par += prz->ecc_size;
-	}
-}
-
-static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
-	size_t buffer_size)
-{
-	int numerr;
-	struct persistent_ram_buffer *buffer = prz->buffer;
-	int ecc_blocks;
-
-	if (!prz->ecc)
-		return 0;
-
-	prz->ecc_block_size = 128;
-	prz->ecc_size = 16;
-	prz->ecc_symsize = 8;
-	prz->ecc_poly = 0x11d;
-
-	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
-	prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
-
-	if (prz->buffer_size > buffer_size) {
-		pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
-		       buffer_size, prz->buffer_size);
-		return -EINVAL;
-	}
-
-	prz->par_buffer = buffer->data + prz->buffer_size;
-	prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
-
-	/*
-	 * first consecutive root is 0
-	 * primitive element to generate roots = 1
-	 */
-	prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
-				  prz->ecc_size);
-	if (prz->rs_decoder == NULL) {
-		pr_info("persistent_ram: init_rs failed\n");
-		return -EINVAL;
-	}
-
-	prz->corrected_bytes = 0;
-	prz->bad_blocks = 0;
-
-	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
-					   prz->par_header);
-	if (numerr > 0) {
-		pr_info("persistent_ram: error in header, %d\n", numerr);
-		prz->corrected_bytes += numerr;
-	} else if (numerr < 0) {
-		pr_info("persistent_ram: uncorrectable error in header\n");
-		prz->bad_blocks++;
-	}
-
-	return 0;
-}
-
-ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
-	char *str, size_t len)
-{
-	ssize_t ret;
-
-	if (prz->corrected_bytes || prz->bad_blocks)
-		ret = snprintf(str, len, ""
-			"\n%d Corrected bytes, %d unrecoverable blocks\n",
-			prz->corrected_bytes, prz->bad_blocks);
-	else
-		ret = snprintf(str, len, "\nNo errors detected\n");
-
-	return ret;
-}
-
-static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
-	const void *s, unsigned int start, unsigned int count)
-{
-	struct persistent_ram_buffer *buffer = prz->buffer;
-	memcpy(buffer->data + start, s, count);
-	persistent_ram_update_ecc(prz, start, count);
-}
-
-static void __init
-persistent_ram_save_old(struct persistent_ram_zone *prz)
-{
-	struct persistent_ram_buffer *buffer = prz->buffer;
-	size_t size = buffer_size(prz);
-	size_t start = buffer_start(prz);
-	char *dest;
-
-	persistent_ram_ecc_old(prz);
-
-	dest = kmalloc(size, GFP_KERNEL);
-	if (dest == NULL) {
-		pr_err("persistent_ram: failed to allocate buffer\n");
-		return;
-	}
-
-	prz->old_log = dest;
-	prz->old_log_size = size;
-	memcpy(prz->old_log, &buffer->data[start], size - start);
-	memcpy(prz->old_log + size - start, &buffer->data[0], start);
-}
-
-int notrace persistent_ram_write(struct persistent_ram_zone *prz,
-	const void *s, unsigned int count)
-{
-	int rem;
-	int c = count;
-	size_t start;
-
-	if (unlikely(c > prz->buffer_size)) {
-		s += c - prz->buffer_size;
-		c = prz->buffer_size;
-	}
-
-	buffer_size_add(prz, c);
-
-	start = buffer_start_add(prz, c);
-
-	rem = prz->buffer_size - start;
-	if (unlikely(rem < c)) {
-		persistent_ram_update(prz, s, start, rem);
-		s += rem;
-		c -= rem;
-		start = 0;
-	}
-	persistent_ram_update(prz, s, start, c);
-
-	persistent_ram_update_header_ecc(prz);
-
-	return count;
-}
-
-size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
-{
-	return prz->old_log_size;
-}
-
-void *persistent_ram_old(struct persistent_ram_zone *prz)
-{
-	return prz->old_log;
-}
-
-void persistent_ram_free_old(struct persistent_ram_zone *prz)
-{
-	kfree(prz->old_log);
-	prz->old_log = NULL;
-	prz->old_log_size = 0;
-}
-
-static void *persistent_ram_vmap(phys_addr_t start, size_t size)
-{
-	struct page **pages;
-	phys_addr_t page_start;
-	unsigned int page_count;
-	pgprot_t prot;
-	unsigned int i;
-	void *vaddr;
-
-	page_start = start - offset_in_page(start);
-	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
-
-	prot = pgprot_noncached(PAGE_KERNEL);
-
-	pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
-	if (!pages) {
-		pr_err("%s: Failed to allocate array for %u pages\n", __func__,
-			page_count);
-		return NULL;
-	}
-
-	for (i = 0; i < page_count; i++) {
-		phys_addr_t addr = page_start + i * PAGE_SIZE;
-		pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
-	}
-	vaddr = vmap(pages, page_count, VM_MAP, prot);
-	kfree(pages);
-
-	return vaddr;
-}
-
-static void *persistent_ram_iomap(phys_addr_t start, size_t size)
-{
-	if (!request_mem_region(start, size, "persistent_ram")) {
-		pr_err("request mem region (0x%llx@0x%llx) failed\n",
-			(unsigned long long)size, (unsigned long long)start);
-		return NULL;
-	}
-
-	return ioremap(start, size);
-}
-
-static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
-		struct persistent_ram_zone *prz)
-{
-	prz->paddr = start;
-	prz->size = size;
-
-	if (pfn_valid(start >> PAGE_SHIFT))
-		prz->vaddr = persistent_ram_vmap(start, size);
-	else
-		prz->vaddr = persistent_ram_iomap(start, size);
-
-	if (!prz->vaddr) {
-		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
-			(unsigned long long)size, (unsigned long long)start);
-		return -ENOMEM;
-	}
-
-	prz->buffer = prz->vaddr + offset_in_page(start);
-	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
-
-	return 0;
-}
-
-static int __init persistent_ram_buffer_init(const char *name,
-		struct persistent_ram_zone *prz)
-{
-	int i;
-	struct persistent_ram *ram;
-	struct persistent_ram_descriptor *desc;
-	phys_addr_t start;
-
-	list_for_each_entry(ram, &persistent_ram_list, node) {
-		start = ram->start;
-		for (i = 0; i < ram->num_descs; i++) {
-			desc = &ram->descs[i];
-			if (!strcmp(desc->name, name))
-				return persistent_ram_buffer_map(start,
-						desc->size, prz);
-			start += desc->size;
-		}
-	}
-
-	return -EINVAL;
-}
-
-static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
-{
-	int ret;
-
-	prz->ecc = ecc;
-
-	ret = persistent_ram_init_ecc(prz, prz->buffer_size);
-	if (ret)
-		return ret;
-
-	if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
-		if (buffer_size(prz) > prz->buffer_size ||
-		    buffer_start(prz) > buffer_size(prz))
-			pr_info("persistent_ram: found existing invalid buffer,"
-				" size %zu, start %zu\n",
-			       buffer_size(prz), buffer_start(prz));
-		else {
-			pr_info("persistent_ram: found existing buffer,"
-				" size %zu, start %zu\n",
-			       buffer_size(prz), buffer_start(prz));
-			persistent_ram_save_old(prz);
-		}
-	} else {
-		pr_info("persistent_ram: no valid data in buffer"
-			" (sig = 0x%08x)\n", prz->buffer->sig);
-	}
-
-	prz->buffer->sig = PERSISTENT_RAM_SIG;
-	atomic_set(&prz->buffer->start, 0);
-	atomic_set(&prz->buffer->size, 0);
-
-	return 0;
-}
-
-void persistent_ram_free(struct persistent_ram_zone *prz)
-{
-	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
-		vunmap(prz->vaddr);
-	} else {
-		iounmap(prz->vaddr);
-		release_mem_region(prz->paddr, prz->size);
-	}
-	persistent_ram_free_old(prz);
-	kfree(prz);
-}
-
-struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
-						       size_t size,
-						       bool ecc)
-{
-	struct persistent_ram_zone *prz;
-	int ret = -ENOMEM;
-
-	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
-	if (!prz) {
-		pr_err("persistent_ram: failed to allocate persistent ram zone\n");
-		goto err;
-	}
-
-	ret = persistent_ram_buffer_map(start, size, prz);
-	if (ret)
-		goto err;
-
-	persistent_ram_post_init(prz, ecc);
-	persistent_ram_update_header_ecc(prz);
-
-	return prz;
-err:
-	kfree(prz);
-	return ERR_PTR(ret);
-}
-
-static  __init
-struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
-{
-	struct persistent_ram_zone *prz;
-	int ret = -ENOMEM;
-
-	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
-	if (!prz) {
-		pr_err("persistent_ram: failed to allocate persistent ram zone\n");
-		goto err;
-	}
-
-	ret = persistent_ram_buffer_init(dev_name(dev), prz);
-	if (ret) {
-		pr_err("persistent_ram: failed to initialize buffer\n");
-		goto err;
-	}
-
-	persistent_ram_post_init(prz, ecc);
-
-	return prz;
-err:
-	kfree(prz);
-	return ERR_PTR(ret);
-}
-
-struct persistent_ram_zone * __init
-persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
-{
-	return __persistent_ram_init(dev, ecc);
-}
-
-int __init persistent_ram_early_init(struct persistent_ram *ram)
-{
-	int ret;
-
-	ret = memblock_reserve(ram->start, ram->size);
-	if (ret) {
-		pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
-			(long)ram->start, (long)(ram->start + ram->size - 1));
-		return ret;
-	}
-
-	list_add_tail(&ram->node, &persistent_ram_list);
-
-	pr_info("Initialized persistent memory from %08lx-%08lx\n",
-		(long)ram->start, (long)(ram->start + ram->size - 1));
-
-	return 0;
-}
diff --git a/drivers/staging/android/persistent_ram.h b/drivers/staging/android/persistent_ram.h
deleted file mode 100644
index d3b2b45..0000000
--- a/drivers/staging/android/persistent_ram.h
+++ /dev/null
@@ -1,84 +0,0 @@ 
-/*
- * Copyright (C) 2011 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.
- *
- */
-
-#ifndef __LINUX_PERSISTENT_RAM_H__
-#define __LINUX_PERSISTENT_RAM_H__
-
-#include <linux/device.h>
-#include <linux/kernel.h>
-#include <linux/list.h>
-#include <linux/types.h>
-#include <linux/init.h>
-
-struct persistent_ram_buffer;
-
-struct persistent_ram_descriptor {
-	const char	*name;
-	phys_addr_t	size;
-};
-
-struct persistent_ram {
-	phys_addr_t	start;
-	phys_addr_t	size;
-
-	int					num_descs;
-	struct persistent_ram_descriptor	*descs;
-
-	struct list_head node;
-};
-
-struct persistent_ram_zone {
-	phys_addr_t paddr;
-	size_t size;
-	void *vaddr;
-	struct persistent_ram_buffer *buffer;
-	size_t buffer_size;
-
-	/* ECC correction */
-	bool ecc;
-	char *par_buffer;
-	char *par_header;
-	struct rs_control *rs_decoder;
-	int corrected_bytes;
-	int bad_blocks;
-	int ecc_block_size;
-	int ecc_size;
-	int ecc_symsize;
-	int ecc_poly;
-
-	char *old_log;
-	size_t old_log_size;
-	size_t old_log_footer_size;
-	bool early;
-};
-
-int persistent_ram_early_init(struct persistent_ram *ram);
-
-struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
-						       size_t size,
-						       bool ecc);
-void persistent_ram_free(struct persistent_ram_zone *prz);
-struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev,
-		bool ecc);
-
-int persistent_ram_write(struct persistent_ram_zone *prz, const void *s,
-	unsigned int count);
-
-size_t persistent_ram_old_size(struct persistent_ram_zone *prz);
-void *persistent_ram_old(struct persistent_ram_zone *prz);
-void persistent_ram_free_old(struct persistent_ram_zone *prz);
-ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
-	char *str, size_t len);
-
-#endif
diff --git a/drivers/staging/android/ram_console.c b/drivers/staging/android/ram_console.c
index ce140ff..82323bb 100644
--- a/drivers/staging/android/ram_console.c
+++ b/drivers/staging/android/ram_console.c
@@ -21,7 +21,7 @@ 
 #include <linux/string.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
-#include "persistent_ram.h"
+#include <linux/pstore_ram.h>
 #include "ram_console.h"
 
 static struct persistent_ram_zone *ram_console_zone;
diff --git a/fs/pstore/Kconfig b/fs/pstore/Kconfig
index ad6e594..139a07c 100644
--- a/fs/pstore/Kconfig
+++ b/fs/pstore/Kconfig
@@ -14,9 +14,12 @@  config PSTORE
 
 config PSTORE_RAM
 	tristate "Log panic/oops to a RAM buffer"
-	depends on HAS_IOMEM
 	depends on PSTORE
-	default n
+	depends on HAS_IOMEM
+	depends on HAVE_MEMBLOCK
+	select REED_SOLOMON
+	select REED_SOLOMON_ENC8
+	select REED_SOLOMON_DEC8
 	help
 	  This enables panic and oops messages to be logged to a circular
 	  buffer in RAM where it can be read back at some later point.
diff --git a/fs/pstore/Makefile b/fs/pstore/Makefile
index 804e376..76d5284 100644
--- a/fs/pstore/Makefile
+++ b/fs/pstore/Makefile
@@ -5,4 +5,4 @@ 
 obj-y += pstore.o
 
 pstore-objs += inode.o platform.o
-obj-$(CONFIG_PSTORE_RAM)	+= ram.o
+obj-$(CONFIG_PSTORE_RAM)	+= ram.o ram_core.o
diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
new file mode 100644
index 0000000..7b9556ba
--- /dev/null
+++ b/fs/pstore/ram_core.c
@@ -0,0 +1,530 @@ 
+/*
+ * Copyright (C) 2012 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/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/memblock.h>
+#include <linux/rslib.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/pstore_ram.h>
+#include <asm/page.h>
+
+struct persistent_ram_buffer {
+	uint32_t    sig;
+	atomic_t    start;
+	atomic_t    size;
+	uint8_t     data[0];
+};
+
+#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
+
+static __initdata LIST_HEAD(persistent_ram_list);
+
+static inline size_t buffer_size(struct persistent_ram_zone *prz)
+{
+	return atomic_read(&prz->buffer->size);
+}
+
+static inline size_t buffer_start(struct persistent_ram_zone *prz)
+{
+	return atomic_read(&prz->buffer->start);
+}
+
+/* increase and wrap the start pointer, returning the old value */
+static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
+{
+	int old;
+	int new;
+
+	do {
+		old = atomic_read(&prz->buffer->start);
+		new = old + a;
+		while (unlikely(new > prz->buffer_size))
+			new -= prz->buffer_size;
+	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
+
+	return old;
+}
+
+/* increase the size counter until it hits the max size */
+static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
+{
+	size_t old;
+	size_t new;
+
+	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
+		return;
+
+	do {
+		old = atomic_read(&prz->buffer->size);
+		new = old + a;
+		if (new > prz->buffer_size)
+			new = prz->buffer_size;
+	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
+}
+
+static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
+	uint8_t *data, size_t len, uint8_t *ecc)
+{
+	int i;
+	uint16_t par[prz->ecc_size];
+
+	/* Initialize the parity buffer */
+	memset(par, 0, sizeof(par));
+	encode_rs8(prz->rs_decoder, data, len, par, 0);
+	for (i = 0; i < prz->ecc_size; i++)
+		ecc[i] = par[i];
+}
+
+static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
+	void *data, size_t len, uint8_t *ecc)
+{
+	int i;
+	uint16_t par[prz->ecc_size];
+
+	for (i = 0; i < prz->ecc_size; i++)
+		par[i] = ecc[i];
+	return decode_rs8(prz->rs_decoder, data, par, len,
+				NULL, 0, NULL, 0, NULL);
+}
+
+static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
+	unsigned int start, unsigned int count)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	uint8_t *buffer_end = buffer->data + prz->buffer_size;
+	uint8_t *block;
+	uint8_t *par;
+	int ecc_block_size = prz->ecc_block_size;
+	int ecc_size = prz->ecc_size;
+	int size = prz->ecc_block_size;
+
+	if (!prz->ecc)
+		return;
+
+	block = buffer->data + (start & ~(ecc_block_size - 1));
+	par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
+
+	do {
+		if (block + ecc_block_size > buffer_end)
+			size = buffer_end - block;
+		persistent_ram_encode_rs8(prz, block, size, par);
+		block += ecc_block_size;
+		par += ecc_size;
+	} while (block < buffer->data + start + count);
+}
+
+static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+
+	if (!prz->ecc)
+		return;
+
+	persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
+				  prz->par_header);
+}
+
+static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	uint8_t *block;
+	uint8_t *par;
+
+	if (!prz->ecc)
+		return;
+
+	block = buffer->data;
+	par = prz->par_buffer;
+	while (block < buffer->data + buffer_size(prz)) {
+		int numerr;
+		int size = prz->ecc_block_size;
+		if (block + size > buffer->data + prz->buffer_size)
+			size = buffer->data + prz->buffer_size - block;
+		numerr = persistent_ram_decode_rs8(prz, block, size, par);
+		if (numerr > 0) {
+			pr_devel("persistent_ram: error in block %p, %d\n",
+			       block, numerr);
+			prz->corrected_bytes += numerr;
+		} else if (numerr < 0) {
+			pr_devel("persistent_ram: uncorrectable error in block %p\n",
+				block);
+			prz->bad_blocks++;
+		}
+		block += prz->ecc_block_size;
+		par += prz->ecc_size;
+	}
+}
+
+static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
+	size_t buffer_size)
+{
+	int numerr;
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	int ecc_blocks;
+
+	if (!prz->ecc)
+		return 0;
+
+	prz->ecc_block_size = 128;
+	prz->ecc_size = 16;
+	prz->ecc_symsize = 8;
+	prz->ecc_poly = 0x11d;
+
+	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
+	prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
+
+	if (prz->buffer_size > buffer_size) {
+		pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
+		       buffer_size, prz->buffer_size);
+		return -EINVAL;
+	}
+
+	prz->par_buffer = buffer->data + prz->buffer_size;
+	prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
+
+	/*
+	 * first consecutive root is 0
+	 * primitive element to generate roots = 1
+	 */
+	prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
+				  prz->ecc_size);
+	if (prz->rs_decoder == NULL) {
+		pr_info("persistent_ram: init_rs failed\n");
+		return -EINVAL;
+	}
+
+	prz->corrected_bytes = 0;
+	prz->bad_blocks = 0;
+
+	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
+					   prz->par_header);
+	if (numerr > 0) {
+		pr_info("persistent_ram: error in header, %d\n", numerr);
+		prz->corrected_bytes += numerr;
+	} else if (numerr < 0) {
+		pr_info("persistent_ram: uncorrectable error in header\n");
+		prz->bad_blocks++;
+	}
+
+	return 0;
+}
+
+ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
+	char *str, size_t len)
+{
+	ssize_t ret;
+
+	if (prz->corrected_bytes || prz->bad_blocks)
+		ret = snprintf(str, len, ""
+			"\n%d Corrected bytes, %d unrecoverable blocks\n",
+			prz->corrected_bytes, prz->bad_blocks);
+	else
+		ret = snprintf(str, len, "\nNo errors detected\n");
+
+	return ret;
+}
+
+static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
+	const void *s, unsigned int start, unsigned int count)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	memcpy(buffer->data + start, s, count);
+	persistent_ram_update_ecc(prz, start, count);
+}
+
+static void __init
+persistent_ram_save_old(struct persistent_ram_zone *prz)
+{
+	struct persistent_ram_buffer *buffer = prz->buffer;
+	size_t size = buffer_size(prz);
+	size_t start = buffer_start(prz);
+	char *dest;
+
+	persistent_ram_ecc_old(prz);
+
+	dest = kmalloc(size, GFP_KERNEL);
+	if (dest == NULL) {
+		pr_err("persistent_ram: failed to allocate buffer\n");
+		return;
+	}
+
+	prz->old_log = dest;
+	prz->old_log_size = size;
+	memcpy(prz->old_log, &buffer->data[start], size - start);
+	memcpy(prz->old_log + size - start, &buffer->data[0], start);
+}
+
+int notrace persistent_ram_write(struct persistent_ram_zone *prz,
+	const void *s, unsigned int count)
+{
+	int rem;
+	int c = count;
+	size_t start;
+
+	if (unlikely(c > prz->buffer_size)) {
+		s += c - prz->buffer_size;
+		c = prz->buffer_size;
+	}
+
+	buffer_size_add(prz, c);
+
+	start = buffer_start_add(prz, c);
+
+	rem = prz->buffer_size - start;
+	if (unlikely(rem < c)) {
+		persistent_ram_update(prz, s, start, rem);
+		s += rem;
+		c -= rem;
+		start = 0;
+	}
+	persistent_ram_update(prz, s, start, c);
+
+	persistent_ram_update_header_ecc(prz);
+
+	return count;
+}
+
+size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
+{
+	return prz->old_log_size;
+}
+
+void *persistent_ram_old(struct persistent_ram_zone *prz)
+{
+	return prz->old_log;
+}
+
+void persistent_ram_free_old(struct persistent_ram_zone *prz)
+{
+	kfree(prz->old_log);
+	prz->old_log = NULL;
+	prz->old_log_size = 0;
+}
+
+static void *persistent_ram_vmap(phys_addr_t start, size_t size)
+{
+	struct page **pages;
+	phys_addr_t page_start;
+	unsigned int page_count;
+	pgprot_t prot;
+	unsigned int i;
+	void *vaddr;
+
+	page_start = start - offset_in_page(start);
+	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
+
+	prot = pgprot_noncached(PAGE_KERNEL);
+
+	pages = kmalloc(sizeof(struct page *) * page_count, GFP_KERNEL);
+	if (!pages) {
+		pr_err("%s: Failed to allocate array for %u pages\n", __func__,
+			page_count);
+		return NULL;
+	}
+
+	for (i = 0; i < page_count; i++) {
+		phys_addr_t addr = page_start + i * PAGE_SIZE;
+		pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
+	}
+	vaddr = vmap(pages, page_count, VM_MAP, prot);
+	kfree(pages);
+
+	return vaddr;
+}
+
+static void *persistent_ram_iomap(phys_addr_t start, size_t size)
+{
+	if (!request_mem_region(start, size, "persistent_ram")) {
+		pr_err("request mem region (0x%llx@0x%llx) failed\n",
+			(unsigned long long)size, (unsigned long long)start);
+		return NULL;
+	}
+
+	return ioremap(start, size);
+}
+
+static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
+		struct persistent_ram_zone *prz)
+{
+	prz->paddr = start;
+	prz->size = size;
+
+	if (pfn_valid(start >> PAGE_SHIFT))
+		prz->vaddr = persistent_ram_vmap(start, size);
+	else
+		prz->vaddr = persistent_ram_iomap(start, size);
+
+	if (!prz->vaddr) {
+		pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
+			(unsigned long long)size, (unsigned long long)start);
+		return -ENOMEM;
+	}
+
+	prz->buffer = prz->vaddr + offset_in_page(start);
+	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
+
+	return 0;
+}
+
+static int __init persistent_ram_buffer_init(const char *name,
+		struct persistent_ram_zone *prz)
+{
+	int i;
+	struct persistent_ram *ram;
+	struct persistent_ram_descriptor *desc;
+	phys_addr_t start;
+
+	list_for_each_entry(ram, &persistent_ram_list, node) {
+		start = ram->start;
+		for (i = 0; i < ram->num_descs; i++) {
+			desc = &ram->descs[i];
+			if (!strcmp(desc->name, name))
+				return persistent_ram_buffer_map(start,
+						desc->size, prz);
+			start += desc->size;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
+{
+	int ret;
+
+	prz->ecc = ecc;
+
+	ret = persistent_ram_init_ecc(prz, prz->buffer_size);
+	if (ret)
+		return ret;
+
+	if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
+		if (buffer_size(prz) > prz->buffer_size ||
+		    buffer_start(prz) > buffer_size(prz))
+			pr_info("persistent_ram: found existing invalid buffer,"
+				" size %zu, start %zu\n",
+			       buffer_size(prz), buffer_start(prz));
+		else {
+			pr_info("persistent_ram: found existing buffer,"
+				" size %zu, start %zu\n",
+			       buffer_size(prz), buffer_start(prz));
+			persistent_ram_save_old(prz);
+		}
+	} else {
+		pr_info("persistent_ram: no valid data in buffer"
+			" (sig = 0x%08x)\n", prz->buffer->sig);
+	}
+
+	prz->buffer->sig = PERSISTENT_RAM_SIG;
+	atomic_set(&prz->buffer->start, 0);
+	atomic_set(&prz->buffer->size, 0);
+
+	return 0;
+}
+
+void persistent_ram_free(struct persistent_ram_zone *prz)
+{
+	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
+		vunmap(prz->vaddr);
+	} else {
+		iounmap(prz->vaddr);
+		release_mem_region(prz->paddr, prz->size);
+	}
+	persistent_ram_free_old(prz);
+	kfree(prz);
+}
+
+struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
+						       size_t size,
+						       bool ecc)
+{
+	struct persistent_ram_zone *prz;
+	int ret = -ENOMEM;
+
+	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
+	if (!prz) {
+		pr_err("persistent_ram: failed to allocate persistent ram zone\n");
+		goto err;
+	}
+
+	ret = persistent_ram_buffer_map(start, size, prz);
+	if (ret)
+		goto err;
+
+	persistent_ram_post_init(prz, ecc);
+	persistent_ram_update_header_ecc(prz);
+
+	return prz;
+err:
+	kfree(prz);
+	return ERR_PTR(ret);
+}
+
+static  __init
+struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
+{
+	struct persistent_ram_zone *prz;
+	int ret = -ENOMEM;
+
+	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
+	if (!prz) {
+		pr_err("persistent_ram: failed to allocate persistent ram zone\n");
+		goto err;
+	}
+
+	ret = persistent_ram_buffer_init(dev_name(dev), prz);
+	if (ret) {
+		pr_err("persistent_ram: failed to initialize buffer\n");
+		goto err;
+	}
+
+	persistent_ram_post_init(prz, ecc);
+
+	return prz;
+err:
+	kfree(prz);
+	return ERR_PTR(ret);
+}
+
+struct persistent_ram_zone * __init
+persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
+{
+	return __persistent_ram_init(dev, ecc);
+}
+
+int __init persistent_ram_early_init(struct persistent_ram *ram)
+{
+	int ret;
+
+	ret = memblock_reserve(ram->start, ram->size);
+	if (ret) {
+		pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
+			(long)ram->start, (long)(ram->start + ram->size - 1));
+		return ret;
+	}
+
+	list_add_tail(&ram->node, &persistent_ram_list);
+
+	pr_info("Initialized persistent memory from %08lx-%08lx\n",
+		(long)ram->start, (long)(ram->start + ram->size - 1));
+
+	return 0;
+}
diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h
index 484fef8..fa4d6e3 100644
--- a/include/linux/pstore_ram.h
+++ b/include/linux/pstore_ram.h
@@ -1,5 +1,87 @@ 
-#ifndef __RAMOOPS_H
-#define __RAMOOPS_H
+/*
+ * Copyright (C) 2010 Marco Stornelli <marco.stornelli@gmail.com>
+ * Copyright (C) 2011 Kees Cook <keescook@chromium.org>
+ * Copyright (C) 2011 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.
+ *
+ */
+
+#ifndef __LINUX_PSTORE_RAM_H__
+#define __LINUX_PSTORE_RAM_H__
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/init.h>
+
+struct persistent_ram_buffer;
+
+struct persistent_ram_descriptor {
+	const char	*name;
+	phys_addr_t	size;
+};
+
+struct persistent_ram {
+	phys_addr_t	start;
+	phys_addr_t	size;
+
+	int					num_descs;
+	struct persistent_ram_descriptor	*descs;
+
+	struct list_head node;
+};
+
+struct persistent_ram_zone {
+	phys_addr_t paddr;
+	size_t size;
+	void *vaddr;
+	struct persistent_ram_buffer *buffer;
+	size_t buffer_size;
+
+	/* ECC correction */
+	bool ecc;
+	char *par_buffer;
+	char *par_header;
+	struct rs_control *rs_decoder;
+	int corrected_bytes;
+	int bad_blocks;
+	int ecc_block_size;
+	int ecc_size;
+	int ecc_symsize;
+	int ecc_poly;
+
+	char *old_log;
+	size_t old_log_size;
+	size_t old_log_footer_size;
+	bool early;
+};
+
+int persistent_ram_early_init(struct persistent_ram *ram);
+
+struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
+						       size_t size,
+						       bool ecc);
+void persistent_ram_free(struct persistent_ram_zone *prz);
+struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev,
+		bool ecc);
+
+int persistent_ram_write(struct persistent_ram_zone *prz, const void *s,
+	unsigned int count);
+
+size_t persistent_ram_old_size(struct persistent_ram_zone *prz);
+void *persistent_ram_old(struct persistent_ram_zone *prz);
+void persistent_ram_free_old(struct persistent_ram_zone *prz);
+ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
+	char *str, size_t len);
 
 /*
  * Ramoops platform data