[deliverable/linux.git] / fs / pstore / ram_core.c

/*
 * 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_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);
}

#ifndef MODULE
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  __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;
}
#endif
Commit	Line	Data
c672528a CC	1	/*
	2	* Copyright (C) 2012 Google, Inc.
	3	*
	4	* This software is licensed under the terms of the GNU General Public
	5	* License version 2, as published by the Free Software Foundation, and
	6	* may be copied, distributed, and modified under those terms.
	7	*
	8	* This program is distributed in the hope that it will be useful,
	9	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	10	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
	12	*
	13	*/
	14
404a6043 CC	15	#include <linux/device.h>
404a6043 CC	16	#include <linux/err.h>
c672528a CC	17	#include <linux/errno.h>
	18	#include <linux/kernel.h>
	19	#include <linux/init.h>
	20	#include <linux/io.h>
404a6043 CC	21	#include <linux/list.h>
404a6043 CC	22	#include <linux/memblock.h>
9cc05ad9	23	#include <linux/rslib.h>
c672528a	24	#include <linux/slab.h>
404a6043	25	#include <linux/vmalloc.h>
cddb8751	26	#include <linux/pstore_ram.h>
24c3d2f3	27	#include <asm/page.h>
c672528a	28
c672528a CC	29	struct persistent_ram_buffer {
c672528a CC	30	uint32_t sig;
808d0387 CC	31	atomic_t start;
808d0387 CC	32	atomic_t size;
c672528a CC	33	uint8_t data[0];
	34	};
	35
	36	#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
	37
404a6043	38	static __initdata LIST_HEAD(persistent_ram_list);
c672528a	39
808d0387 CC	40	static inline size_t buffer_size(struct persistent_ram_zone *prz)
	41	{
	42	return atomic_read(&prz->buffer->size);
	43	}
	44
	45	static inline size_t buffer_start(struct persistent_ram_zone *prz)
	46	{
	47	return atomic_read(&prz->buffer->start);
	48	}
	49
	50	/* increase and wrap the start pointer, returning the old value */
	51	static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
	52	{
	53	int old;
	54	int new;
	55
	56	do {
	57	old = atomic_read(&prz->buffer->start);
	58	new = old + a;
	59	while (unlikely(new > prz->buffer_size))
	60	new -= prz->buffer_size;
	61	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
	62
	63	return old;
	64	}
	65
	66	/* increase the size counter until it hits the max size */
	67	static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
	68	{
	69	size_t old;
	70	size_t new;
	71
	72	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
	73	return;
	74
	75	do {
	76	old = atomic_read(&prz->buffer->size);
	77	new = old + a;
	78	if (new > prz->buffer_size)
	79	new = prz->buffer_size;
	80	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
	81	}
	82
a15d0b36	83	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	84	uint8_t data, size_t len, uint8_t ecc)
	85	{
	86	int i;
9cc05ad9 CC	87	uint16_t par[prz->ecc_size];
9cc05ad9 CC	88
c672528a CC	89	/* Initialize the parity buffer */
	90	memset(par, 0, sizeof(par));
	91	encode_rs8(prz->rs_decoder, data, len, par, 0);
9cc05ad9	92	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	93	ecc[i] = par[i];
	94	}
	95
	96	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	97	void data, size_t len, uint8_t ecc)
	98	{
	99	int i;
9cc05ad9 CC	100	uint16_t par[prz->ecc_size];
	101
	102	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	103	par[i] = ecc[i];
	104	return decode_rs8(prz->rs_decoder, data, par, len,
	105	NULL, 0, NULL, 0, NULL);
	106	}
c672528a	107
a15d0b36	108	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	109	unsigned int start, unsigned int count)
c672528a CC	110	{
c672528a CC	111	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	112	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	113	uint8_t *block;
	114	uint8_t *par;
9cc05ad9 CC	115	int ecc_block_size = prz->ecc_block_size;
	116	int ecc_size = prz->ecc_size;
	117	int size = prz->ecc_block_size;
	118
	119	if (!prz->ecc)
	120	return;
	121
808d0387 CC	122	block = buffer->data + (start & ~(ecc_block_size - 1));
	123	par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
	124
c672528a	125	do {
9cc05ad9	126	if (block + ecc_block_size > buffer_end)
c672528a CC	127	size = buffer_end - block;
c672528a CC	128	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	129	block += ecc_block_size;
9cc05ad9 CC	130	par += ecc_size;
808d0387	131	} while (block < buffer->data + start + count);
c672528a CC	132	}
c672528a CC	133
9cc05ad9	134	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	135	{
c672528a CC	136	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	137
9cc05ad9 CC	138	if (!prz->ecc)
	139	return;
	140
c672528a CC	141	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	142	prz->par_header);
c672528a CC	143	}
c672528a CC	144
9cc05ad9	145	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	146	{
c672528a CC	147	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	148	uint8_t *block;
	149	uint8_t *par;
	150
9cc05ad9 CC	151	if (!prz->ecc)
	152	return;
	153
c672528a CC	154	block = buffer->data;
c672528a CC	155	par = prz->par_buffer;
808d0387	156	while (block < buffer->data + buffer_size(prz)) {
c672528a	157	int numerr;
9cc05ad9	158	int size = prz->ecc_block_size;
c672528a CC	159	if (block + size > buffer->data + prz->buffer_size)
	160	size = buffer->data + prz->buffer_size - block;
	161	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	162	if (numerr > 0) {
9cc05ad9	163	pr_devel("persistent_ram: error in block %p, %d\n",
c672528a	164	block, numerr);
c672528a CC	165	prz->corrected_bytes += numerr;
c672528a CC	166	} else if (numerr < 0) {
9cc05ad9	167	pr_devel("persistent_ram: uncorrectable error in block %p\n",
c672528a	168	block);
c672528a CC	169	prz->bad_blocks++;
c672528a CC	170	}
9cc05ad9 CC	171	block += prz->ecc_block_size;
	172	par += prz->ecc_size;
	173	}
	174	}
	175
	176	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
	177	size_t buffer_size)
	178	{
	179	int numerr;
	180	struct persistent_ram_buffer *buffer = prz->buffer;
	181	int ecc_blocks;
	182
	183	if (!prz->ecc)
	184	return 0;
	185
	186	prz->ecc_block_size = 128;
	187	prz->ecc_size = 16;
	188	prz->ecc_symsize = 8;
	189	prz->ecc_poly = 0x11d;
	190
	191	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
	192	prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
	193
	194	if (prz->buffer_size > buffer_size) {
	195	pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
	196	buffer_size, prz->buffer_size);
	197	return -EINVAL;
	198	}
	199
	200	prz->par_buffer = buffer->data + prz->buffer_size;
	201	prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
	202
	203	/*
	204	* first consecutive root is 0
	205	* primitive element to generate roots = 1
	206	*/
	207	prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
	208	prz->ecc_size);
	209	if (prz->rs_decoder == NULL) {
	210	pr_info("persistent_ram: init_rs failed\n");
	211	return -EINVAL;
c672528a	212	}
9cc05ad9 CC	213
	214	prz->corrected_bytes = 0;
	215	prz->bad_blocks = 0;
	216
	217	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	218	prz->par_header);
	219	if (numerr > 0) {
	220	pr_info("persistent_ram: error in header, %d\n", numerr);
	221	prz->corrected_bytes += numerr;
	222	} else if (numerr < 0) {
	223	pr_info("persistent_ram: uncorrectable error in header\n");
	224	prz->bad_blocks++;
	225	}
	226
	227	return 0;
	228	}
	229
	230	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	231	char *str, size_t len)
	232	{
	233	ssize_t ret;
	234
	235	if (prz->corrected_bytes \|\| prz->bad_blocks)
	236	ret = snprintf(str, len, ""
	237	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	238	prz->corrected_bytes, prz->bad_blocks);
	239	else
	240	ret = snprintf(str, len, "\nNo errors detected\n");
	241
	242	return ret;
	243	}
	244
a15d0b36	245	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	246	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	247	{
9cc05ad9 CC	248	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	249	memcpy(buffer->data + start, s, count);
808d0387 CC	250	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	251	}
	252
	253	static void __init
	254	persistent_ram_save_old(struct persistent_ram_zone *prz)
	255	{
	256	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	257	size_t size = buffer_size(prz);
808d0387 CC	258	size_t start = buffer_start(prz);
9cc05ad9 CC	259	char *dest;
	260
	261	persistent_ram_ecc_old(prz);
c672528a	262
808d0387	263	dest = kmalloc(size, GFP_KERNEL);
c672528a CC	264	if (dest == NULL) {
	265	pr_err("persistent_ram: failed to allocate buffer\n");
	266	return;
	267	}
	268
	269	prz->old_log = dest;
808d0387 CC	270	prz->old_log_size = size;
	271	memcpy(prz->old_log, &buffer->data[start], size - start);
	272	memcpy(prz->old_log + size - start, &buffer->data[0], start);
c672528a CC	273	}
c672528a CC	274
a15d0b36	275	int notrace persistent_ram_write(struct persistent_ram_zone *prz,
c672528a CC	276	const void *s, unsigned int count)
	277	{
	278	int rem;
	279	int c = count;
808d0387	280	size_t start;
c672528a	281
808d0387	282	if (unlikely(c > prz->buffer_size)) {
c672528a CC	283	s += c - prz->buffer_size;
	284	c = prz->buffer_size;
	285	}
808d0387	286
484dd30e	287	buffer_size_add(prz, c);
808d0387 CC	288
	289	start = buffer_start_add(prz, c);
	290
	291	rem = prz->buffer_size - start;
	292	if (unlikely(rem < c)) {
	293	persistent_ram_update(prz, s, start, rem);
c672528a CC	294	s += rem;
c672528a CC	295	c -= rem;
808d0387	296	start = 0;
c672528a	297	}
808d0387	298	persistent_ram_update(prz, s, start, c);
c672528a	299
9cc05ad9	300	persistent_ram_update_header_ecc(prz);
c672528a CC	301
	302	return count;
	303	}
	304
c672528a CC	305	size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
	306	{
	307	return prz->old_log_size;
	308	}
	309
	310	void persistent_ram_old(struct persistent_ram_zone prz)
	311	{
	312	return prz->old_log;
	313	}
	314
	315	void persistent_ram_free_old(struct persistent_ram_zone *prz)
	316	{
	317	kfree(prz->old_log);
	318	prz->old_log = NULL;
	319	prz->old_log_size = 0;
	320	}
	321
2b1321e4	322	static void *persistent_ram_vmap(phys_addr_t start, size_t size)
c672528a	323	{
404a6043 CC	324	struct page **pages;
	325	phys_addr_t page_start;
	326	unsigned int page_count;
	327	pgprot_t prot;
	328	unsigned int i;
2b1321e4	329	void *vaddr;
404a6043 CC	330
	331	page_start = start - offset_in_page(start);
	332	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	333
	334	prot = pgprot_noncached(PAGE_KERNEL);
	335
	336	pages = kmalloc(sizeof(struct page ) page_count, GFP_KERNEL);
	337	if (!pages) {
	338	pr_err("%s: Failed to allocate array for %u pages\n", __func__,
	339	page_count);
2b1321e4	340	return NULL;
404a6043 CC	341	}
	342
	343	for (i = 0; i < page_count; i++) {
	344	phys_addr_t addr = page_start + i * PAGE_SIZE;
	345	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	346	}
2b1321e4	347	vaddr = vmap(pages, page_count, VM_MAP, prot);
404a6043	348	kfree(pages);
2b1321e4 AV	349
	350	return vaddr;
	351	}
	352
24c3d2f3 AV	353	static void *persistent_ram_iomap(phys_addr_t start, size_t size)
	354	{
	355	if (!request_mem_region(start, size, "persistent_ram")) {
	356	pr_err("request mem region (0x%llx@0x%llx) failed\n",
	357	(unsigned long long)size, (unsigned long long)start);
	358	return NULL;
	359	}
	360
	361	return ioremap(start, size);
	362	}
	363
2b1321e4 AV	364	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
	365	struct persistent_ram_zone *prz)
	366	{
d3b48769 AV	367	prz->paddr = start;
	368	prz->size = size;
	369
24c3d2f3 AV	370	if (pfn_valid(start >> PAGE_SHIFT))
	371	prz->vaddr = persistent_ram_vmap(start, size);
	372	else
	373	prz->vaddr = persistent_ram_iomap(start, size);
	374
404a6043	375	if (!prz->vaddr) {
2b1321e4 AV	376	pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
2b1321e4 AV	377	(unsigned long long)size, (unsigned long long)start);
404a6043 CC	378	return -ENOMEM;
	379	}
	380
	381	prz->buffer = prz->vaddr + offset_in_page(start);
	382	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	383
	384	return 0;
	385	}
	386
bb4206f2	387	static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
404a6043	388	{
bb4206f2	389	int ret;
c672528a	390
9cc05ad9	391	prz->ecc = ecc;
bb4206f2	392
404a6043	393	ret = persistent_ram_init_ecc(prz, prz->buffer_size);
9cc05ad9	394	if (ret)
bb4206f2	395	return ret;
c672528a	396
404a6043	397	if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
808d0387 CC	398	if (buffer_size(prz) > prz->buffer_size \|\|
	399	buffer_start(prz) > buffer_size(prz))
	400	pr_info("persistent_ram: found existing invalid buffer,"
f56d711b	401	" size %zu, start %zu\n",
808d0387	402	buffer_size(prz), buffer_start(prz));
c672528a	403	else {
808d0387	404	pr_info("persistent_ram: found existing buffer,"
f56d711b	405	" size %zu, start %zu\n",
808d0387	406	buffer_size(prz), buffer_start(prz));
c672528a CC	407	persistent_ram_save_old(prz);
	408	}
	409	} else {
808d0387 CC	410	pr_info("persistent_ram: no valid data in buffer"
808d0387 CC	411	" (sig = 0x%08x)\n", prz->buffer->sig);
c672528a CC	412	}
c672528a CC	413
404a6043	414	prz->buffer->sig = PERSISTENT_RAM_SIG;
808d0387 CC	415	atomic_set(&prz->buffer->start, 0);
808d0387 CC	416	atomic_set(&prz->buffer->size, 0);
c672528a	417
bb4206f2 AV	418	return 0;
	419	}
	420
d3b48769 AV	421	void persistent_ram_free(struct persistent_ram_zone *prz)
	422	{
	423	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
	424	vunmap(prz->vaddr);
	425	} else {
	426	iounmap(prz->vaddr);
	427	release_mem_region(prz->paddr, prz->size);
	428	}
	429	persistent_ram_free_old(prz);
	430	kfree(prz);
	431	}
	432
8cf5aff8 AV	433	struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
	434	size_t size,
	435	bool ecc)
	436	{
	437	struct persistent_ram_zone *prz;
	438	int ret = -ENOMEM;
	439
	440	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	441	if (!prz) {
	442	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	443	goto err;
	444	}
	445
	446	ret = persistent_ram_buffer_map(start, size, prz);
	447	if (ret)
	448	goto err;
	449
	450	persistent_ram_post_init(prz, ecc);
	451	persistent_ram_update_header_ecc(prz);
	452
	453	return prz;
	454	err:
	455	kfree(prz);
	456	return ERR_PTR(ret);
	457	}
	458
7dd8e9be AV	459	#ifndef MODULE
	460	static int __init persistent_ram_buffer_init(const char *name,
	461	struct persistent_ram_zone *prz)
	462	{
	463	int i;
	464	struct persistent_ram *ram;
	465	struct persistent_ram_descriptor *desc;
	466	phys_addr_t start;
	467
	468	list_for_each_entry(ram, &persistent_ram_list, node) {
	469	start = ram->start;
	470	for (i = 0; i < ram->num_descs; i++) {
	471	desc = &ram->descs[i];
	472	if (!strcmp(desc->name, name))
	473	return persistent_ram_buffer_map(start,
	474	desc->size, prz);
	475	start += desc->size;
	476	}
	477	}
	478
	479	return -EINVAL;
	480	}
	481
bb4206f2 AV	482	static __init
	483	struct persistent_ram_zone __persistent_ram_init(struct device dev, bool ecc)
	484	{
	485	struct persistent_ram_zone *prz;
	486	int ret = -ENOMEM;
	487
	488	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	489	if (!prz) {
	490	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	491	goto err;
	492	}
	493
	494	ret = persistent_ram_buffer_init(dev_name(dev), prz);
	495	if (ret) {
	496	pr_err("persistent_ram: failed to initialize buffer\n");
	497	goto err;
	498	}
	499
	500	persistent_ram_post_init(prz, ecc);
	501
404a6043	502	return prz;
474a8988 JJ	503	err:
	504	kfree(prz);
	505	return ERR_PTR(ret);
404a6043	506	}
c672528a	507
404a6043 CC	508	struct persistent_ram_zone * __init
	509	persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
	510	{
	511	return __persistent_ram_init(dev, ecc);
c672528a CC	512	}
c672528a CC	513
404a6043	514	int __init persistent_ram_early_init(struct persistent_ram *ram)
c672528a	515	{
404a6043 CC	516	int ret;
	517
	518	ret = memblock_reserve(ram->start, ram->size);
	519	if (ret) {
	520	pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
	521	(long)ram->start, (long)(ram->start + ram->size - 1));
	522	return ret;
	523	}
	524
	525	list_add_tail(&ram->node, &persistent_ram_list);
	526
	527	pr_info("Initialized persistent memory from %08lx-%08lx\n",
	528	(long)ram->start, (long)(ram->start + ram->size - 1));
	529
	530	return 0;
c672528a	531	}
7dd8e9be	532	#endif