[mirror_ubuntu-artful-kernel.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 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_size)
		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_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_size)
		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,
				   int ecc_size)
{
	int numerr;
	struct persistent_ram_buffer *buffer = prz->buffer;
	int ecc_blocks;
	size_t ecc_total;
	int ecc_symsize = 8;
	int ecc_poly = 0x11d;

	if (!ecc_size)
		return 0;

	prz->ecc_block_size = 128;
	prz->ecc_size = ecc_size;

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

	/*
	 * first consecutive root is 0
	 * primitive element to generate roots = 1
	 */
	prz->rs_decoder = init_rs(ecc_symsize, 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);
}

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;
	}

	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 __devinit persistent_ram_post_init(struct persistent_ram_zone *prz,
					      int ecc_size)
{
	int ret;

	ret = persistent_ram_init_ecc(prz, ecc_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_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 = PERSISTENT_RAM_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 * __devinit persistent_ram_new(phys_addr_t start,
							  size_t size,
							  int ecc_size)
{
	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, ecc_size);
	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 */
	49	static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
	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 */
	65	static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
	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
a15d0b36	81	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	82	uint8_t data, size_t len, uint8_t ecc)
	83	{
	84	int i;
9cc05ad9 CC	85	uint16_t par[prz->ecc_size];
9cc05ad9 CC	86
c672528a CC	87	/* Initialize the parity buffer */
	88	memset(par, 0, sizeof(par));
	89	encode_rs8(prz->rs_decoder, data, len, par, 0);
9cc05ad9	90	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	91	ecc[i] = par[i];
	92	}
	93
	94	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	95	void data, size_t len, uint8_t ecc)
	96	{
	97	int i;
9cc05ad9 CC	98	uint16_t par[prz->ecc_size];
	99
	100	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	101	par[i] = ecc[i];
	102	return decode_rs8(prz->rs_decoder, data, par, len,
	103	NULL, 0, NULL, 0, NULL);
	104	}
c672528a	105
a15d0b36	106	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	107	unsigned int start, unsigned int count)
c672528a CC	108	{
c672528a CC	109	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	110	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	111	uint8_t *block;
	112	uint8_t *par;
9cc05ad9 CC	113	int ecc_block_size = prz->ecc_block_size;
	114	int ecc_size = prz->ecc_size;
	115	int size = prz->ecc_block_size;
	116
c1743cbc	117	if (!prz->ecc_size)
9cc05ad9 CC	118	return;
9cc05ad9 CC	119
808d0387 CC	120	block = buffer->data + (start & ~(ecc_block_size - 1));
	121	par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
	122
c672528a	123	do {
9cc05ad9	124	if (block + ecc_block_size > buffer_end)
c672528a CC	125	size = buffer_end - block;
c672528a CC	126	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	127	block += ecc_block_size;
9cc05ad9 CC	128	par += ecc_size;
808d0387	129	} while (block < buffer->data + start + count);
c672528a CC	130	}
c672528a CC	131
9cc05ad9	132	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	133	{
c672528a CC	134	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	135
c1743cbc	136	if (!prz->ecc_size)
9cc05ad9 CC	137	return;
9cc05ad9 CC	138
c672528a CC	139	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	140	prz->par_header);
c672528a CC	141	}
c672528a CC	142
9cc05ad9	143	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	144	{
c672528a CC	145	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	146	uint8_t *block;
	147	uint8_t *par;
	148
c1743cbc	149	if (!prz->ecc_size)
9cc05ad9 CC	150	return;
9cc05ad9 CC	151
c672528a CC	152	block = buffer->data;
c672528a CC	153	par = prz->par_buffer;
808d0387	154	while (block < buffer->data + buffer_size(prz)) {
c672528a	155	int numerr;
9cc05ad9	156	int size = prz->ecc_block_size;
c672528a CC	157	if (block + size > buffer->data + prz->buffer_size)
	158	size = buffer->data + prz->buffer_size - block;
	159	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	160	if (numerr > 0) {
9cc05ad9	161	pr_devel("persistent_ram: error in block %p, %d\n",
c672528a	162	block, numerr);
c672528a CC	163	prz->corrected_bytes += numerr;
c672528a CC	164	} else if (numerr < 0) {
9cc05ad9	165	pr_devel("persistent_ram: uncorrectable error in block %p\n",
c672528a	166	block);
c672528a CC	167	prz->bad_blocks++;
c672528a CC	168	}
9cc05ad9 CC	169	block += prz->ecc_block_size;
	170	par += prz->ecc_size;
	171	}
	172	}
	173
5ca5d4e6 AV	174	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
5ca5d4e6 AV	175	int ecc_size)
9cc05ad9 CC	176	{
	177	int numerr;
	178	struct persistent_ram_buffer *buffer = prz->buffer;
	179	int ecc_blocks;
1e6a9e56	180	size_t ecc_total;
4a53ffae AV	181	int ecc_symsize = 8;
4a53ffae AV	182	int ecc_poly = 0x11d;
9cc05ad9	183
c1743cbc	184	if (!ecc_size)
9cc05ad9 CC	185	return 0;
	186
	187	prz->ecc_block_size = 128;
5ca5d4e6	188	prz->ecc_size = ecc_size;
9cc05ad9 CC	189
9cc05ad9 CC	190	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
1e6a9e56 AV	191	ecc_total = (ecc_blocks + 1) * prz->ecc_size;
	192	if (ecc_total >= prz->buffer_size) {
	193	pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
	194	__func__, prz->ecc_size, ecc_total, prz->buffer_size);
9cc05ad9 CC	195	return -EINVAL;
	196	}
	197
1e6a9e56	198	prz->buffer_size -= ecc_total;
9cc05ad9 CC	199	prz->par_buffer = buffer->data + prz->buffer_size;
	200	prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
	201
	202	/*
	203	* first consecutive root is 0
	204	* primitive element to generate roots = 1
	205	*/
4a53ffae	206	prz->rs_decoder = init_rs(ecc_symsize, ecc_poly, 0, 1, prz->ecc_size);
9cc05ad9 CC	207	if (prz->rs_decoder == NULL) {
	208	pr_info("persistent_ram: init_rs failed\n");
	209	return -EINVAL;
c672528a	210	}
9cc05ad9 CC	211
	212	prz->corrected_bytes = 0;
	213	prz->bad_blocks = 0;
	214
	215	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	216	prz->par_header);
	217	if (numerr > 0) {
	218	pr_info("persistent_ram: error in header, %d\n", numerr);
	219	prz->corrected_bytes += numerr;
	220	} else if (numerr < 0) {
	221	pr_info("persistent_ram: uncorrectable error in header\n");
	222	prz->bad_blocks++;
	223	}
	224
	225	return 0;
	226	}
	227
	228	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	229	char *str, size_t len)
	230	{
	231	ssize_t ret;
	232
	233	if (prz->corrected_bytes \|\| prz->bad_blocks)
	234	ret = snprintf(str, len, ""
	235	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	236	prz->corrected_bytes, prz->bad_blocks);
	237	else
	238	ret = snprintf(str, len, "\nNo errors detected\n");
	239
	240	return ret;
	241	}
	242
a15d0b36	243	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	244	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	245	{
9cc05ad9 CC	246	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	247	memcpy(buffer->data + start, s, count);
808d0387 CC	248	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	249	}
9cc05ad9 CC	250
201e4aca	251	void persistent_ram_save_old(struct persistent_ram_zone *prz)
9cc05ad9 CC	252	{
9cc05ad9 CC	253	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	254	size_t size = buffer_size(prz);
808d0387 CC	255	size_t start = buffer_start(prz);
9cc05ad9	256
201e4aca AV	257	if (!size)
201e4aca AV	258	return;
c672528a	259
201e4aca AV	260	if (!prz->old_log) {
	261	persistent_ram_ecc_old(prz);
	262	prz->old_log = kmalloc(size, GFP_KERNEL);
	263	}
	264	if (!prz->old_log) {
c672528a CC	265	pr_err("persistent_ram: failed to allocate buffer\n");
	266	return;
	267	}
	268
808d0387 CC	269	prz->old_log_size = size;
	270	memcpy(prz->old_log, &buffer->data[start], size - start);
	271	memcpy(prz->old_log + size - start, &buffer->data[0], start);
c672528a CC	272	}
c672528a CC	273
a15d0b36	274	int notrace persistent_ram_write(struct persistent_ram_zone *prz,
c672528a CC	275	const void *s, unsigned int count)
	276	{
	277	int rem;
	278	int c = count;
808d0387	279	size_t start;
c672528a	280
808d0387	281	if (unlikely(c > prz->buffer_size)) {
c672528a CC	282	s += c - prz->buffer_size;
	283	c = prz->buffer_size;
	284	}
808d0387	285
484dd30e	286	buffer_size_add(prz, c);
808d0387 CC	287
	288	start = buffer_start_add(prz, c);
	289
	290	rem = prz->buffer_size - start;
	291	if (unlikely(rem < c)) {
	292	persistent_ram_update(prz, s, start, rem);
c672528a CC	293	s += rem;
c672528a CC	294	c -= rem;
808d0387	295	start = 0;
c672528a	296	}
808d0387	297	persistent_ram_update(prz, s, start, c);
c672528a	298
9cc05ad9	299	persistent_ram_update_header_ecc(prz);
c672528a CC	300
	301	return count;
	302	}
	303
c672528a CC	304	size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
	305	{
	306	return prz->old_log_size;
	307	}
	308
	309	void persistent_ram_old(struct persistent_ram_zone prz)
	310	{
	311	return prz->old_log;
	312	}
	313
	314	void persistent_ram_free_old(struct persistent_ram_zone *prz)
	315	{
	316	kfree(prz->old_log);
	317	prz->old_log = NULL;
	318	prz->old_log_size = 0;
	319	}
	320
fce39793 AV	321	void persistent_ram_zap(struct persistent_ram_zone *prz)
	322	{
	323	atomic_set(&prz->buffer->start, 0);
	324	atomic_set(&prz->buffer->size, 0);
	325	persistent_ram_update_header_ecc(prz);
	326	}
	327
2b1321e4	328	static void *persistent_ram_vmap(phys_addr_t start, size_t size)
c672528a	329	{
404a6043 CC	330	struct page **pages;
	331	phys_addr_t page_start;
	332	unsigned int page_count;
	333	pgprot_t prot;
	334	unsigned int i;
2b1321e4	335	void *vaddr;
404a6043 CC	336
	337	page_start = start - offset_in_page(start);
	338	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	339
	340	prot = pgprot_noncached(PAGE_KERNEL);
	341
	342	pages = kmalloc(sizeof(struct page ) page_count, GFP_KERNEL);
	343	if (!pages) {
	344	pr_err("%s: Failed to allocate array for %u pages\n", __func__,
	345	page_count);
2b1321e4	346	return NULL;
404a6043 CC	347	}
	348
	349	for (i = 0; i < page_count; i++) {
	350	phys_addr_t addr = page_start + i * PAGE_SIZE;
	351	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	352	}
2b1321e4	353	vaddr = vmap(pages, page_count, VM_MAP, prot);
404a6043	354	kfree(pages);
2b1321e4 AV	355
	356	return vaddr;
	357	}
	358
24c3d2f3 AV	359	static void *persistent_ram_iomap(phys_addr_t start, size_t size)
	360	{
	361	if (!request_mem_region(start, size, "persistent_ram")) {
	362	pr_err("request mem region (0x%llx@0x%llx) failed\n",
	363	(unsigned long long)size, (unsigned long long)start);
	364	return NULL;
	365	}
	366
	367	return ioremap(start, size);
	368	}
	369
2b1321e4 AV	370	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
	371	struct persistent_ram_zone *prz)
	372	{
d3b48769 AV	373	prz->paddr = start;
	374	prz->size = size;
	375
24c3d2f3 AV	376	if (pfn_valid(start >> PAGE_SHIFT))
	377	prz->vaddr = persistent_ram_vmap(start, size);
	378	else
	379	prz->vaddr = persistent_ram_iomap(start, size);
	380
404a6043	381	if (!prz->vaddr) {
2b1321e4 AV	382	pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
2b1321e4 AV	383	(unsigned long long)size, (unsigned long long)start);
404a6043 CC	384	return -ENOMEM;
	385	}
	386
	387	prz->buffer = prz->vaddr + offset_in_page(start);
	388	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	389
	390	return 0;
	391	}
	392
924d3711	393	static int __devinit persistent_ram_post_init(struct persistent_ram_zone *prz,
5ca5d4e6	394	int ecc_size)
404a6043	395	{
bb4206f2	396	int ret;
c672528a	397
5ca5d4e6	398	ret = persistent_ram_init_ecc(prz, ecc_size);
9cc05ad9	399	if (ret)
bb4206f2	400	return ret;
c672528a	401
404a6043	402	if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
808d0387 CC	403	if (buffer_size(prz) > prz->buffer_size \|\|
	404	buffer_start(prz) > buffer_size(prz))
	405	pr_info("persistent_ram: found existing invalid buffer,"
f56d711b	406	" size %zu, start %zu\n",
808d0387	407	buffer_size(prz), buffer_start(prz));
c672528a	408	else {
602b5be4	409	pr_debug("persistent_ram: found existing buffer,"
f56d711b	410	" size %zu, start %zu\n",
808d0387	411	buffer_size(prz), buffer_start(prz));
c672528a	412	persistent_ram_save_old(prz);
25b63da6	413	return 0;
c672528a CC	414	}
c672528a CC	415	} else {
602b5be4	416	pr_debug("persistent_ram: no valid data in buffer"
808d0387	417	" (sig = 0x%08x)\n", prz->buffer->sig);
c672528a CC	418	}
c672528a CC	419
404a6043	420	prz->buffer->sig = PERSISTENT_RAM_SIG;
fce39793	421	persistent_ram_zap(prz);
c672528a	422
bb4206f2 AV	423	return 0;
	424	}
	425
d3b48769 AV	426	void persistent_ram_free(struct persistent_ram_zone *prz)
d3b48769 AV	427	{
beeb9432 AV	428	if (!prz)
	429	return;
	430
	431	if (prz->vaddr) {
	432	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
	433	vunmap(prz->vaddr);
	434	} else {
	435	iounmap(prz->vaddr);
	436	release_mem_region(prz->paddr, prz->size);
	437	}
	438	prz->vaddr = NULL;
d3b48769 AV	439	}
	440	persistent_ram_free_old(prz);
	441	kfree(prz);
	442	}
	443
924d3711 AV	444	struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start,
924d3711 AV	445	size_t size,
5ca5d4e6	446	int ecc_size)
8cf5aff8 AV	447	{
	448	struct persistent_ram_zone *prz;
	449	int ret = -ENOMEM;
	450
	451	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	452	if (!prz) {
	453	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	454	goto err;
	455	}
	456
	457	ret = persistent_ram_buffer_map(start, size, prz);
	458	if (ret)
	459	goto err;
	460
5ca5d4e6	461	ret = persistent_ram_post_init(prz, ecc_size);
beeb9432 AV	462	if (ret)
beeb9432 AV	463	goto err;
8cf5aff8 AV	464
	465	return prz;
	466	err:
beeb9432	467	persistent_ram_free(prz);
8cf5aff8 AV	468	return ERR_PTR(ret);
8cf5aff8 AV	469	}