[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.
 *
 */

#define pr_fmt(fmt) "persistent_ram: " fmt

#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 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 size_t buffer_start_add_atomic(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 void buffer_size_add_atomic(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 DEFINE_RAW_SPINLOCK(buffer_lock);

/* increase and wrap the start pointer, returning the old value */
static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
{
	int old;
	int new;
	unsigned long flags;

	raw_spin_lock_irqsave(&buffer_lock, flags);

	old = atomic_read(&prz->buffer->start);
	new = old + a;
	while (unlikely(new >= prz->buffer_size))
		new -= prz->buffer_size;
	atomic_set(&prz->buffer->start, new);

	raw_spin_unlock_irqrestore(&buffer_lock, flags);

	return old;
}

/* increase the size counter until it hits the max size */
static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
{
	size_t old;
	size_t new;
	unsigned long flags;

	raw_spin_lock_irqsave(&buffer_lock, flags);

	old = atomic_read(&prz->buffer->size);
	if (old == prz->buffer_size)
		goto exit;

	new = old + a;
	if (new > prz->buffer_size)
		new = prz->buffer_size;
	atomic_set(&prz->buffer->size, new);

exit:
	raw_spin_unlock_irqrestore(&buffer_lock, flags);
}

static size_t (*buffer_start_add)(struct persistent_ram_zone *, size_t) = buffer_start_add_atomic;
static void (*buffer_size_add)(struct persistent_ram_zone *, size_t) = buffer_size_add_atomic;

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_info.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_info.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_info.ecc_size];

	for (i = 0; i < prz->ecc_info.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_info.block_size;
	int ecc_size = prz->ecc_info.ecc_size;
	int size = ecc_block_size;

	if (!ecc_size)
		return;

	block = buffer->data + (start & ~(ecc_block_size - 1));
	par = prz->par_buffer + (start / ecc_block_size) * 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_info.ecc_size)
		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_info.ecc_size)
		return;

	block = buffer->data;
	par = prz->par_buffer;
	while (block < buffer->data + buffer_size(prz)) {
		int numerr;
		int size = prz->ecc_info.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("error in block %p, %d\n", block, numerr);
			prz->corrected_bytes += numerr;
		} else if (numerr < 0) {
			pr_devel("uncorrectable error in block %p\n", block);
			prz->bad_blocks++;
		}
		block += prz->ecc_info.block_size;
		par += prz->ecc_info.ecc_size;
	}
}

static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
				   struct persistent_ram_ecc_info *ecc_info)
{
	int numerr;
	struct persistent_ram_buffer *buffer = prz->buffer;
	int ecc_blocks;
	size_t ecc_total;

	if (!ecc_info || !ecc_info->ecc_size)
		return 0;

	prz->ecc_info.block_size = ecc_info->block_size ?: 128;
	prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
	prz->ecc_info.symsize = ecc_info->symsize ?: 8;
	prz->ecc_info.poly = ecc_info->poly ?: 0x11d;

	ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
				  prz->ecc_info.block_size +
				  prz->ecc_info.ecc_size);
	ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
	if (ecc_total >= prz->buffer_size) {
		pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
		       __func__, prz->ecc_info.ecc_size,
		       ecc_total, prz->buffer_size);
		return -EINVAL;
	}

	prz->buffer_size -= ecc_total;
	prz->par_buffer = buffer->data + prz->buffer_size;
	prz->par_header = prz->par_buffer +
			  ecc_blocks * prz->ecc_info.ecc_size;

	/*
	 * first consecutive root is 0
	 * primitive element to generate roots = 1
	 */
	prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
				  0, 1, prz->ecc_info.ecc_size);
	if (prz->rs_decoder == NULL) {
		pr_info("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("error in header, %d\n", numerr);
		prz->corrected_bytes += numerr;
	} else if (numerr < 0) {
		pr_info("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->ecc_info.ecc_size)
		return 0;

	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);
}

void 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);

	if (!size)
		return;

	if (!prz->old_log) {
		persistent_ram_ecc_old(prz);
		prz->old_log = kmalloc(size, GFP_KERNEL);
	}
	if (!prz->old_log) {
		pr_err("failed to allocate buffer\n");
		return;
	}

	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;
}

void persistent_ram_zap(struct persistent_ram_zone *prz)
{
	atomic_set(&prz->buffer->start, 0);
	atomic_set(&prz->buffer->size, 0);
	persistent_ram_update_header_ecc(prz);
}

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_array(page_count, sizeof(struct page *), 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;
	}

	buffer_start_add = buffer_start_add_locked;
	buffer_size_add = buffer_size_add_locked;

	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 persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
				    struct persistent_ram_ecc_info *ecc_info)
{
	int ret;

	ret = persistent_ram_init_ecc(prz, ecc_info);
	if (ret)
		return ret;

	sig ^= PERSISTENT_RAM_SIG;

	if (prz->buffer->sig == sig) {
		if (buffer_size(prz) > prz->buffer_size ||
		    buffer_start(prz) > buffer_size(prz))
			pr_info("found existing invalid buffer, size %zu, start %zu\n",
				buffer_size(prz), buffer_start(prz));
		else {
			pr_debug("found existing buffer, size %zu, start %zu\n",
				 buffer_size(prz), buffer_start(prz));
			persistent_ram_save_old(prz);
			return 0;
		}
	} else {
		pr_debug("no valid data in buffer (sig = 0x%08x)\n",
			 prz->buffer->sig);
	}

	prz->buffer->sig = sig;
	persistent_ram_zap(prz);

	return 0;
}

void persistent_ram_free(struct persistent_ram_zone *prz)
{
	if (!prz)
		return;

	if (prz->vaddr) {
		if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
			vunmap(prz->vaddr);
		} else {
			iounmap(prz->vaddr);
			release_mem_region(prz->paddr, prz->size);
		}
		prz->vaddr = NULL;
	}
	persistent_ram_free_old(prz);
	kfree(prz);
}

struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
			u32 sig, struct persistent_ram_ecc_info *ecc_info)
{
	struct persistent_ram_zone *prz;
	int ret = -ENOMEM;

	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	if (!prz) {
		pr_err("failed to allocate persistent ram zone\n");
		goto err;
	}

	ret = persistent_ram_buffer_map(start, size, prz);
	if (ret)
		goto err;

	ret = persistent_ram_post_init(prz, sig, ecc_info);
	if (ret)
		goto err;

	return prz;
err:
	persistent_ram_free(prz);
	return ERR_PTR(ret);
}
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
ef748853 FF	15	#define pr_fmt(fmt) "persistent_ram: " fmt
ef748853 FF	16
404a6043 CC	17	#include <linux/device.h>
404a6043 CC	18	#include <linux/err.h>
c672528a CC	19	#include <linux/errno.h>
	20	#include <linux/kernel.h>
	21	#include <linux/init.h>
	22	#include <linux/io.h>
404a6043 CC	23	#include <linux/list.h>
404a6043 CC	24	#include <linux/memblock.h>
9cc05ad9	25	#include <linux/rslib.h>
c672528a	26	#include <linux/slab.h>
404a6043	27	#include <linux/vmalloc.h>
cddb8751	28	#include <linux/pstore_ram.h>
24c3d2f3	29	#include <asm/page.h>
c672528a	30
c672528a CC	31	struct persistent_ram_buffer {
c672528a CC	32	uint32_t sig;
808d0387 CC	33	atomic_t start;
808d0387 CC	34	atomic_t size;
c672528a CC	35	uint8_t data[0];
	36	};
	37
	38	#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
	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 */
0405a5ce	51	static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
808d0387 CC	52	{
	53	int old;
	54	int new;
	55
	56	do {
	57	old = atomic_read(&prz->buffer->start);
	58	new = old + a;
017321cf	59	while (unlikely(new >= prz->buffer_size))
808d0387 CC	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 */
0405a5ce	67	static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a)
808d0387 CC	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
0405a5ce RH	83	static DEFINE_RAW_SPINLOCK(buffer_lock);
	84
	85	/* increase and wrap the start pointer, returning the old value */
	86	static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
	87	{
	88	int old;
	89	int new;
	90	unsigned long flags;
	91
	92	raw_spin_lock_irqsave(&buffer_lock, flags);
	93
	94	old = atomic_read(&prz->buffer->start);
	95	new = old + a;
017321cf	96	while (unlikely(new >= prz->buffer_size))
0405a5ce RH	97	new -= prz->buffer_size;
	98	atomic_set(&prz->buffer->start, new);
	99
	100	raw_spin_unlock_irqrestore(&buffer_lock, flags);
	101
	102	return old;
	103	}
	104
	105	/* increase the size counter until it hits the max size */
	106	static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
	107	{
	108	size_t old;
	109	size_t new;
	110	unsigned long flags;
	111
	112	raw_spin_lock_irqsave(&buffer_lock, flags);
	113
	114	old = atomic_read(&prz->buffer->size);
	115	if (old == prz->buffer_size)
	116	goto exit;
	117
	118	new = old + a;
	119	if (new > prz->buffer_size)
	120	new = prz->buffer_size;
	121	atomic_set(&prz->buffer->size, new);
	122
	123	exit:
	124	raw_spin_unlock_irqrestore(&buffer_lock, flags);
	125	}
	126
	127	static size_t (buffer_start_add)(struct persistent_ram_zone , size_t) = buffer_start_add_atomic;
	128	static void (buffer_size_add)(struct persistent_ram_zone , size_t) = buffer_size_add_atomic;
	129
a15d0b36	130	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	131	uint8_t data, size_t len, uint8_t ecc)
	132	{
	133	int i;
c31ad081	134	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	135
c672528a CC	136	/* Initialize the parity buffer */
	137	memset(par, 0, sizeof(par));
	138	encode_rs8(prz->rs_decoder, data, len, par, 0);
c31ad081	139	for (i = 0; i < prz->ecc_info.ecc_size; i++)
c672528a CC	140	ecc[i] = par[i];
	141	}
	142
	143	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	144	void data, size_t len, uint8_t ecc)
	145	{
	146	int i;
c31ad081	147	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	148
c31ad081	149	for (i = 0; i < prz->ecc_info.ecc_size; i++)
c672528a CC	150	par[i] = ecc[i];
	151	return decode_rs8(prz->rs_decoder, data, par, len,
	152	NULL, 0, NULL, 0, NULL);
	153	}
c672528a	154
a15d0b36	155	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	156	unsigned int start, unsigned int count)
c672528a CC	157	{
c672528a CC	158	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	159	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	160	uint8_t *block;
	161	uint8_t *par;
c31ad081 AH	162	int ecc_block_size = prz->ecc_info.block_size;
	163	int ecc_size = prz->ecc_info.ecc_size;
	164	int size = ecc_block_size;
9cc05ad9	165
c31ad081	166	if (!ecc_size)
9cc05ad9 CC	167	return;
9cc05ad9 CC	168
808d0387	169	block = buffer->data + (start & ~(ecc_block_size - 1));
c31ad081	170	par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
808d0387	171
c672528a	172	do {
9cc05ad9	173	if (block + ecc_block_size > buffer_end)
c672528a CC	174	size = buffer_end - block;
c672528a CC	175	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	176	block += ecc_block_size;
9cc05ad9 CC	177	par += ecc_size;
808d0387	178	} while (block < buffer->data + start + count);
c672528a CC	179	}
c672528a CC	180
9cc05ad9	181	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	182	{
c672528a CC	183	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	184
c31ad081	185	if (!prz->ecc_info.ecc_size)
9cc05ad9 CC	186	return;
9cc05ad9 CC	187
c672528a CC	188	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	189	prz->par_header);
c672528a CC	190	}
c672528a CC	191
9cc05ad9	192	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	193	{
c672528a CC	194	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	195	uint8_t *block;
	196	uint8_t *par;
	197
c31ad081	198	if (!prz->ecc_info.ecc_size)
9cc05ad9 CC	199	return;
9cc05ad9 CC	200
c672528a CC	201	block = buffer->data;
c672528a CC	202	par = prz->par_buffer;
808d0387	203	while (block < buffer->data + buffer_size(prz)) {
c672528a	204	int numerr;
c31ad081	205	int size = prz->ecc_info.block_size;
c672528a CC	206	if (block + size > buffer->data + prz->buffer_size)
	207	size = buffer->data + prz->buffer_size - block;
	208	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	209	if (numerr > 0) {
ef748853	210	pr_devel("error in block %p, %d\n", block, numerr);
c672528a CC	211	prz->corrected_bytes += numerr;
c672528a CC	212	} else if (numerr < 0) {
ef748853	213	pr_devel("uncorrectable error in block %p\n", block);
c672528a CC	214	prz->bad_blocks++;
c672528a CC	215	}
c31ad081 AH	216	block += prz->ecc_info.block_size;
c31ad081 AH	217	par += prz->ecc_info.ecc_size;
9cc05ad9 CC	218	}
	219	}
	220
5ca5d4e6	221	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
c31ad081	222	struct persistent_ram_ecc_info *ecc_info)
9cc05ad9 CC	223	{
	224	int numerr;
	225	struct persistent_ram_buffer *buffer = prz->buffer;
	226	int ecc_blocks;
1e6a9e56	227	size_t ecc_total;
9cc05ad9	228
c31ad081	229	if (!ecc_info \|\| !ecc_info->ecc_size)
9cc05ad9 CC	230	return 0;
9cc05ad9 CC	231
c31ad081 AH	232	prz->ecc_info.block_size = ecc_info->block_size ?: 128;
	233	prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
	234	prz->ecc_info.symsize = ecc_info->symsize ?: 8;
	235	prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
9cc05ad9	236
c31ad081 AH	237	ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
	238	prz->ecc_info.block_size +
	239	prz->ecc_info.ecc_size);
	240	ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
1e6a9e56 AV	241	if (ecc_total >= prz->buffer_size) {
1e6a9e56 AV	242	pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
c31ad081 AH	243	__func__, prz->ecc_info.ecc_size,
c31ad081 AH	244	ecc_total, prz->buffer_size);
9cc05ad9 CC	245	return -EINVAL;
	246	}
	247
1e6a9e56	248	prz->buffer_size -= ecc_total;
9cc05ad9	249	prz->par_buffer = buffer->data + prz->buffer_size;
c31ad081 AH	250	prz->par_header = prz->par_buffer +
c31ad081 AH	251	ecc_blocks * prz->ecc_info.ecc_size;
9cc05ad9 CC	252
	253	/*
	254	* first consecutive root is 0
	255	* primitive element to generate roots = 1
	256	*/
c31ad081 AH	257	prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
c31ad081 AH	258	0, 1, prz->ecc_info.ecc_size);
9cc05ad9	259	if (prz->rs_decoder == NULL) {
ef748853	260	pr_info("init_rs failed\n");
9cc05ad9	261	return -EINVAL;
c672528a	262	}
9cc05ad9 CC	263
	264	prz->corrected_bytes = 0;
	265	prz->bad_blocks = 0;
	266
	267	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	268	prz->par_header);
	269	if (numerr > 0) {
ef748853	270	pr_info("error in header, %d\n", numerr);
9cc05ad9 CC	271	prz->corrected_bytes += numerr;
9cc05ad9 CC	272	} else if (numerr < 0) {
ef748853	273	pr_info("uncorrectable error in header\n");
9cc05ad9 CC	274	prz->bad_blocks++;
	275	}
	276
	277	return 0;
	278	}
	279
	280	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	281	char *str, size_t len)
	282	{
	283	ssize_t ret;
	284
bd08ec33 AH	285	if (!prz->ecc_info.ecc_size)
	286	return 0;
	287
9cc05ad9 CC	288	if (prz->corrected_bytes \|\| prz->bad_blocks)
	289	ret = snprintf(str, len, ""
	290	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	291	prz->corrected_bytes, prz->bad_blocks);
	292	else
	293	ret = snprintf(str, len, "\nNo errors detected\n");
	294
	295	return ret;
	296	}
	297
a15d0b36	298	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	299	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	300	{
9cc05ad9 CC	301	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	302	memcpy(buffer->data + start, s, count);
808d0387 CC	303	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	304	}
9cc05ad9 CC	305
201e4aca	306	void persistent_ram_save_old(struct persistent_ram_zone *prz)
9cc05ad9 CC	307	{
9cc05ad9 CC	308	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	309	size_t size = buffer_size(prz);
808d0387 CC	310	size_t start = buffer_start(prz);
9cc05ad9	311
201e4aca AV	312	if (!size)
201e4aca AV	313	return;
c672528a	314
201e4aca AV	315	if (!prz->old_log) {
	316	persistent_ram_ecc_old(prz);
	317	prz->old_log = kmalloc(size, GFP_KERNEL);
	318	}
	319	if (!prz->old_log) {
ef748853	320	pr_err("failed to allocate buffer\n");
c672528a CC	321	return;
	322	}
	323
808d0387 CC	324	prz->old_log_size = size;
	325	memcpy(prz->old_log, &buffer->data[start], size - start);
	326	memcpy(prz->old_log + size - start, &buffer->data[0], start);
c672528a CC	327	}
c672528a CC	328
a15d0b36	329	int notrace persistent_ram_write(struct persistent_ram_zone *prz,
c672528a CC	330	const void *s, unsigned int count)
	331	{
	332	int rem;
	333	int c = count;
808d0387	334	size_t start;
c672528a	335
808d0387	336	if (unlikely(c > prz->buffer_size)) {
c672528a CC	337	s += c - prz->buffer_size;
	338	c = prz->buffer_size;
	339	}
808d0387	340
484dd30e	341	buffer_size_add(prz, c);
808d0387 CC	342
	343	start = buffer_start_add(prz, c);
	344
	345	rem = prz->buffer_size - start;
	346	if (unlikely(rem < c)) {
	347	persistent_ram_update(prz, s, start, rem);
c672528a CC	348	s += rem;
c672528a CC	349	c -= rem;
808d0387	350	start = 0;
c672528a	351	}
808d0387	352	persistent_ram_update(prz, s, start, c);
c672528a	353
9cc05ad9	354	persistent_ram_update_header_ecc(prz);
c672528a CC	355
	356	return count;
	357	}
	358
c672528a CC	359	size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
	360	{
	361	return prz->old_log_size;
	362	}
	363
	364	void persistent_ram_old(struct persistent_ram_zone prz)
	365	{
	366	return prz->old_log;
	367	}
	368
	369	void persistent_ram_free_old(struct persistent_ram_zone *prz)
	370	{
	371	kfree(prz->old_log);
	372	prz->old_log = NULL;
	373	prz->old_log_size = 0;
	374	}
	375
fce39793 AV	376	void persistent_ram_zap(struct persistent_ram_zone *prz)
	377	{
	378	atomic_set(&prz->buffer->start, 0);
	379	atomic_set(&prz->buffer->size, 0);
	380	persistent_ram_update_header_ecc(prz);
	381	}
	382
2b1321e4	383	static void *persistent_ram_vmap(phys_addr_t start, size_t size)
c672528a	384	{
404a6043 CC	385	struct page **pages;
	386	phys_addr_t page_start;
	387	unsigned int page_count;
	388	pgprot_t prot;
	389	unsigned int i;
2b1321e4	390	void *vaddr;
404a6043 CC	391
	392	page_start = start - offset_in_page(start);
	393	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	394
	395	prot = pgprot_noncached(PAGE_KERNEL);
	396
b8f52d89	397	pages = kmalloc_array(page_count, sizeof(struct page *), GFP_KERNEL);
404a6043	398	if (!pages) {
ef748853 FF	399	pr_err("%s: Failed to allocate array for %u pages\n",
ef748853 FF	400	__func__, page_count);
2b1321e4	401	return NULL;
404a6043 CC	402	}
	403
	404	for (i = 0; i < page_count; i++) {
	405	phys_addr_t addr = page_start + i * PAGE_SIZE;
	406	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	407	}
2b1321e4	408	vaddr = vmap(pages, page_count, VM_MAP, prot);
404a6043	409	kfree(pages);
2b1321e4 AV	410
	411	return vaddr;
	412	}
	413
24c3d2f3 AV	414	static void *persistent_ram_iomap(phys_addr_t start, size_t size)
	415	{
	416	if (!request_mem_region(start, size, "persistent_ram")) {
	417	pr_err("request mem region (0x%llx@0x%llx) failed\n",
	418	(unsigned long long)size, (unsigned long long)start);
	419	return NULL;
	420	}
	421
0405a5ce RH	422	buffer_start_add = buffer_start_add_locked;
	423	buffer_size_add = buffer_size_add_locked;
	424
24c3d2f3 AV	425	return ioremap(start, size);
	426	}
	427
2b1321e4 AV	428	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
	429	struct persistent_ram_zone *prz)
	430	{
d3b48769 AV	431	prz->paddr = start;
	432	prz->size = size;
	433
24c3d2f3 AV	434	if (pfn_valid(start >> PAGE_SHIFT))
	435	prz->vaddr = persistent_ram_vmap(start, size);
	436	else
	437	prz->vaddr = persistent_ram_iomap(start, size);
	438
404a6043	439	if (!prz->vaddr) {
2b1321e4 AV	440	pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
2b1321e4 AV	441	(unsigned long long)size, (unsigned long long)start);
404a6043 CC	442	return -ENOMEM;
	443	}
	444
	445	prz->buffer = prz->vaddr + offset_in_page(start);
	446	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	447
	448	return 0;
	449	}
	450
f568f6ca	451	static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
c31ad081	452	struct persistent_ram_ecc_info *ecc_info)
404a6043	453	{
bb4206f2	454	int ret;
c672528a	455
c31ad081	456	ret = persistent_ram_init_ecc(prz, ecc_info);
9cc05ad9	457	if (ret)
bb4206f2	458	return ret;
c672528a	459
cbe7cbf5 AV	460	sig ^= PERSISTENT_RAM_SIG;
	461
	462	if (prz->buffer->sig == sig) {
808d0387 CC	463	if (buffer_size(prz) > prz->buffer_size \|\|
808d0387 CC	464	buffer_start(prz) > buffer_size(prz))
ef748853 FF	465	pr_info("found existing invalid buffer, size %zu, start %zu\n",
ef748853 FF	466	buffer_size(prz), buffer_start(prz));
c672528a	467	else {
ef748853 FF	468	pr_debug("found existing buffer, size %zu, start %zu\n",
ef748853 FF	469	buffer_size(prz), buffer_start(prz));
c672528a	470	persistent_ram_save_old(prz);
25b63da6	471	return 0;
c672528a CC	472	}
c672528a CC	473	} else {
ef748853 FF	474	pr_debug("no valid data in buffer (sig = 0x%08x)\n",
ef748853 FF	475	prz->buffer->sig);
c672528a CC	476	}
c672528a CC	477
cbe7cbf5	478	prz->buffer->sig = sig;
fce39793	479	persistent_ram_zap(prz);
c672528a	480
bb4206f2 AV	481	return 0;
	482	}
	483
d3b48769 AV	484	void persistent_ram_free(struct persistent_ram_zone *prz)
d3b48769 AV	485	{
beeb9432 AV	486	if (!prz)
	487	return;
	488
	489	if (prz->vaddr) {
	490	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
	491	vunmap(prz->vaddr);
	492	} else {
	493	iounmap(prz->vaddr);
	494	release_mem_region(prz->paddr, prz->size);
	495	}
	496	prz->vaddr = NULL;
d3b48769 AV	497	}
	498	persistent_ram_free_old(prz);
	499	kfree(prz);
	500	}
	501
f568f6ca	502	struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
c31ad081	503	u32 sig, struct persistent_ram_ecc_info *ecc_info)
8cf5aff8 AV	504	{
	505	struct persistent_ram_zone *prz;
	506	int ret = -ENOMEM;
	507
	508	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	509	if (!prz) {
ef748853	510	pr_err("failed to allocate persistent ram zone\n");
8cf5aff8 AV	511	goto err;
	512	}
	513
	514	ret = persistent_ram_buffer_map(start, size, prz);
	515	if (ret)
	516	goto err;
	517
c31ad081	518	ret = persistent_ram_post_init(prz, sig, ecc_info);
beeb9432 AV	519	if (ret)
beeb9432 AV	520	goto err;
8cf5aff8 AV	521
	522	return prz;
	523	err:
beeb9432	524	persistent_ram_free(prz);
8cf5aff8 AV	525	return ERR_PTR(ret);
8cf5aff8 AV	526	}