[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 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("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_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("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->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("persistent_ram: 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(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;
	}

	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("persistent_ram: found existing invalid buffer,"
				" size %zu, start %zu\n",
			       buffer_size(prz), buffer_start(prz));
		else {
			pr_debug("persistent_ram: found existing buffer,"
				" size %zu, start %zu\n",
			       buffer_size(prz), buffer_start(prz));
			persistent_ram_save_old(prz);
			return 0;
		}
	} else {
		pr_debug("persistent_ram: 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("persistent_ram: 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
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
808d0387 CC	38	static inline size_t buffer_size(struct persistent_ram_zone *prz)
	39	{
	40	return atomic_read(&prz->buffer->size);
	41	}
	42
	43	static inline size_t buffer_start(struct persistent_ram_zone *prz)
	44	{
	45	return atomic_read(&prz->buffer->start);
	46	}
	47
	48	/* increase and wrap the start pointer, returning the old value */
0405a5ce	49	static size_t buffer_start_add_atomic(struct persistent_ram_zone *prz, size_t a)
808d0387 CC	50	{
	51	int old;
	52	int new;
	53
	54	do {
	55	old = atomic_read(&prz->buffer->start);
	56	new = old + a;
	57	while (unlikely(new > prz->buffer_size))
	58	new -= prz->buffer_size;
	59	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
	60
	61	return old;
	62	}
	63
	64	/* increase the size counter until it hits the max size */
0405a5ce	65	static void buffer_size_add_atomic(struct persistent_ram_zone *prz, size_t a)
808d0387 CC	66	{
	67	size_t old;
	68	size_t new;
	69
	70	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
	71	return;
	72
	73	do {
	74	old = atomic_read(&prz->buffer->size);
	75	new = old + a;
	76	if (new > prz->buffer_size)
	77	new = prz->buffer_size;
	78	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
	79	}
	80
0405a5ce RH	81	static DEFINE_RAW_SPINLOCK(buffer_lock);
	82
	83	/* increase and wrap the start pointer, returning the old value */
	84	static size_t buffer_start_add_locked(struct persistent_ram_zone *prz, size_t a)
	85	{
	86	int old;
	87	int new;
	88	unsigned long flags;
	89
	90	raw_spin_lock_irqsave(&buffer_lock, flags);
	91
	92	old = atomic_read(&prz->buffer->start);
	93	new = old + a;
	94	while (unlikely(new > prz->buffer_size))
	95	new -= prz->buffer_size;
	96	atomic_set(&prz->buffer->start, new);
	97
	98	raw_spin_unlock_irqrestore(&buffer_lock, flags);
	99
	100	return old;
	101	}
	102
	103	/* increase the size counter until it hits the max size */
	104	static void buffer_size_add_locked(struct persistent_ram_zone *prz, size_t a)
	105	{
	106	size_t old;
	107	size_t new;
	108	unsigned long flags;
	109
	110	raw_spin_lock_irqsave(&buffer_lock, flags);
	111
	112	old = atomic_read(&prz->buffer->size);
	113	if (old == prz->buffer_size)
	114	goto exit;
	115
	116	new = old + a;
	117	if (new > prz->buffer_size)
	118	new = prz->buffer_size;
	119	atomic_set(&prz->buffer->size, new);
	120
	121	exit:
	122	raw_spin_unlock_irqrestore(&buffer_lock, flags);
	123	}
	124
	125	static size_t (buffer_start_add)(struct persistent_ram_zone , size_t) = buffer_start_add_atomic;
	126	static void (buffer_size_add)(struct persistent_ram_zone , size_t) = buffer_size_add_atomic;
	127
a15d0b36	128	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	129	uint8_t data, size_t len, uint8_t ecc)
	130	{
	131	int i;
c31ad081	132	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	133
c672528a CC	134	/* Initialize the parity buffer */
	135	memset(par, 0, sizeof(par));
	136	encode_rs8(prz->rs_decoder, data, len, par, 0);
c31ad081	137	for (i = 0; i < prz->ecc_info.ecc_size; i++)
c672528a CC	138	ecc[i] = par[i];
	139	}
	140
	141	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	142	void data, size_t len, uint8_t ecc)
	143	{
	144	int i;
c31ad081	145	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	146
c31ad081	147	for (i = 0; i < prz->ecc_info.ecc_size; i++)
c672528a CC	148	par[i] = ecc[i];
	149	return decode_rs8(prz->rs_decoder, data, par, len,
	150	NULL, 0, NULL, 0, NULL);
	151	}
c672528a	152
a15d0b36	153	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	154	unsigned int start, unsigned int count)
c672528a CC	155	{
c672528a CC	156	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	157	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	158	uint8_t *block;
	159	uint8_t *par;
c31ad081 AH	160	int ecc_block_size = prz->ecc_info.block_size;
	161	int ecc_size = prz->ecc_info.ecc_size;
	162	int size = ecc_block_size;
9cc05ad9	163
c31ad081	164	if (!ecc_size)
9cc05ad9 CC	165	return;
9cc05ad9 CC	166
808d0387	167	block = buffer->data + (start & ~(ecc_block_size - 1));
c31ad081	168	par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
808d0387	169
c672528a	170	do {
9cc05ad9	171	if (block + ecc_block_size > buffer_end)
c672528a CC	172	size = buffer_end - block;
c672528a CC	173	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	174	block += ecc_block_size;
9cc05ad9 CC	175	par += ecc_size;
808d0387	176	} while (block < buffer->data + start + count);
c672528a CC	177	}
c672528a CC	178
9cc05ad9	179	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	180	{
c672528a CC	181	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	182
c31ad081	183	if (!prz->ecc_info.ecc_size)
9cc05ad9 CC	184	return;
9cc05ad9 CC	185
c672528a CC	186	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	187	prz->par_header);
c672528a CC	188	}
c672528a CC	189
9cc05ad9	190	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	191	{
c672528a CC	192	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	193	uint8_t *block;
	194	uint8_t *par;
	195
c31ad081	196	if (!prz->ecc_info.ecc_size)
9cc05ad9 CC	197	return;
9cc05ad9 CC	198
c672528a CC	199	block = buffer->data;
c672528a CC	200	par = prz->par_buffer;
808d0387	201	while (block < buffer->data + buffer_size(prz)) {
c672528a	202	int numerr;
c31ad081	203	int size = prz->ecc_info.block_size;
c672528a CC	204	if (block + size > buffer->data + prz->buffer_size)
	205	size = buffer->data + prz->buffer_size - block;
	206	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	207	if (numerr > 0) {
9cc05ad9	208	pr_devel("persistent_ram: error in block %p, %d\n",
c672528a	209	block, numerr);
c672528a CC	210	prz->corrected_bytes += numerr;
c672528a CC	211	} else if (numerr < 0) {
9cc05ad9	212	pr_devel("persistent_ram: uncorrectable error in block %p\n",
c672528a	213	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 CC	259	if (prz->rs_decoder == NULL) {
	260	pr_info("persistent_ram: init_rs failed\n");
	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) {
	270	pr_info("persistent_ram: error in header, %d\n", numerr);
	271	prz->corrected_bytes += numerr;
	272	} else if (numerr < 0) {
	273	pr_info("persistent_ram: uncorrectable error in header\n");
	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) {
c672528a CC	320	pr_err("persistent_ram: failed to allocate buffer\n");
	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
	397	pages = kmalloc(sizeof(struct page ) page_count, GFP_KERNEL);
	398	if (!pages) {
	399	pr_err("%s: Failed to allocate array for %u pages\n", __func__,
	400	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 \|\|
	464	buffer_start(prz) > buffer_size(prz))
	465	pr_info("persistent_ram: found existing invalid buffer,"
f56d711b	466	" size %zu, start %zu\n",
808d0387	467	buffer_size(prz), buffer_start(prz));
c672528a	468	else {
602b5be4	469	pr_debug("persistent_ram: found existing buffer,"
f56d711b	470	" size %zu, start %zu\n",
808d0387	471	buffer_size(prz), buffer_start(prz));
c672528a	472	persistent_ram_save_old(prz);
25b63da6	473	return 0;
c672528a CC	474	}
c672528a CC	475	} else {
602b5be4	476	pr_debug("persistent_ram: no valid data in buffer"
808d0387	477	" (sig = 0x%08x)\n", prz->buffer->sig);
c672528a CC	478	}
c672528a CC	479
cbe7cbf5	480	prz->buffer->sig = sig;
fce39793	481	persistent_ram_zap(prz);
c672528a	482
bb4206f2 AV	483	return 0;
	484	}
	485
d3b48769 AV	486	void persistent_ram_free(struct persistent_ram_zone *prz)
d3b48769 AV	487	{
beeb9432 AV	488	if (!prz)
	489	return;
	490
	491	if (prz->vaddr) {
	492	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
	493	vunmap(prz->vaddr);
	494	} else {
	495	iounmap(prz->vaddr);
	496	release_mem_region(prz->paddr, prz->size);
	497	}
	498	prz->vaddr = NULL;
d3b48769 AV	499	}
	500	persistent_ram_free_old(prz);
	501	kfree(prz);
	502	}
	503
f568f6ca	504	struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
c31ad081	505	u32 sig, struct persistent_ram_ecc_info *ecc_info)
8cf5aff8 AV	506	{
	507	struct persistent_ram_zone *prz;
	508	int ret = -ENOMEM;
	509
	510	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	511	if (!prz) {
	512	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	513	goto err;
	514	}
	515
	516	ret = persistent_ram_buffer_map(start, size, prz);
	517	if (ret)
	518	goto err;
	519
c31ad081	520	ret = persistent_ram_post_init(prz, sig, ecc_info);
beeb9432 AV	521	if (ret)
beeb9432 AV	522	goto err;
8cf5aff8 AV	523
	524	return prz;
	525	err:
beeb9432	526	persistent_ram_free(prz);
8cf5aff8 AV	527	return ERR_PTR(ret);
8cf5aff8 AV	528	}