[GitHub/mt8127/android_kernel_alcatel_ttab.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_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;
	}

	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 */
	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;
c31ad081	85	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	86
c672528a CC	87	/* Initialize the parity buffer */
	88	memset(par, 0, sizeof(par));
	89	encode_rs8(prz->rs_decoder, data, len, par, 0);
c31ad081	90	for (i = 0; i < prz->ecc_info.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;
c31ad081	98	uint16_t par[prz->ecc_info.ecc_size];
9cc05ad9	99
c31ad081	100	for (i = 0; i < prz->ecc_info.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;
c31ad081 AH	113	int ecc_block_size = prz->ecc_info.block_size;
	114	int ecc_size = prz->ecc_info.ecc_size;
	115	int size = ecc_block_size;
9cc05ad9	116
c31ad081	117	if (!ecc_size)
9cc05ad9 CC	118	return;
9cc05ad9 CC	119
808d0387	120	block = buffer->data + (start & ~(ecc_block_size - 1));
c31ad081	121	par = prz->par_buffer + (start / ecc_block_size) * ecc_size;
808d0387	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
c31ad081	136	if (!prz->ecc_info.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
c31ad081	149	if (!prz->ecc_info.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;
c31ad081	156	int size = prz->ecc_info.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	}
c31ad081 AH	169	block += prz->ecc_info.block_size;
c31ad081 AH	170	par += prz->ecc_info.ecc_size;
9cc05ad9 CC	171	}
	172	}
	173
5ca5d4e6	174	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
c31ad081	175	struct persistent_ram_ecc_info *ecc_info)
9cc05ad9 CC	176	{
	177	int numerr;
	178	struct persistent_ram_buffer *buffer = prz->buffer;
	179	int ecc_blocks;
1e6a9e56	180	size_t ecc_total;
9cc05ad9	181
c31ad081	182	if (!ecc_info \|\| !ecc_info->ecc_size)
9cc05ad9 CC	183	return 0;
9cc05ad9 CC	184
c31ad081 AH	185	prz->ecc_info.block_size = ecc_info->block_size ?: 128;
	186	prz->ecc_info.ecc_size = ecc_info->ecc_size ?: 16;
	187	prz->ecc_info.symsize = ecc_info->symsize ?: 8;
	188	prz->ecc_info.poly = ecc_info->poly ?: 0x11d;
9cc05ad9	189
c31ad081 AH	190	ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_info.ecc_size,
	191	prz->ecc_info.block_size +
	192	prz->ecc_info.ecc_size);
	193	ecc_total = (ecc_blocks + 1) * prz->ecc_info.ecc_size;
1e6a9e56 AV	194	if (ecc_total >= prz->buffer_size) {
1e6a9e56 AV	195	pr_err("%s: invalid ecc_size %u (total %zu, buffer size %zu)\n",
c31ad081 AH	196	__func__, prz->ecc_info.ecc_size,
c31ad081 AH	197	ecc_total, prz->buffer_size);
9cc05ad9 CC	198	return -EINVAL;
	199	}
	200
1e6a9e56	201	prz->buffer_size -= ecc_total;
9cc05ad9	202	prz->par_buffer = buffer->data + prz->buffer_size;
c31ad081 AH	203	prz->par_header = prz->par_buffer +
c31ad081 AH	204	ecc_blocks * prz->ecc_info.ecc_size;
9cc05ad9 CC	205
	206	/*
	207	* first consecutive root is 0
	208	* primitive element to generate roots = 1
	209	*/
c31ad081 AH	210	prz->rs_decoder = init_rs(prz->ecc_info.symsize, prz->ecc_info.poly,
c31ad081 AH	211	0, 1, prz->ecc_info.ecc_size);
9cc05ad9 CC	212	if (prz->rs_decoder == NULL) {
	213	pr_info("persistent_ram: init_rs failed\n");
	214	return -EINVAL;
c672528a	215	}
9cc05ad9 CC	216
	217	prz->corrected_bytes = 0;
	218	prz->bad_blocks = 0;
	219
	220	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	221	prz->par_header);
	222	if (numerr > 0) {
	223	pr_info("persistent_ram: error in header, %d\n", numerr);
	224	prz->corrected_bytes += numerr;
	225	} else if (numerr < 0) {
	226	pr_info("persistent_ram: uncorrectable error in header\n");
	227	prz->bad_blocks++;
	228	}
	229
	230	return 0;
	231	}
	232
	233	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	234	char *str, size_t len)
	235	{
	236	ssize_t ret;
	237
bd08ec33 AH	238	if (!prz->ecc_info.ecc_size)
	239	return 0;
	240
9cc05ad9 CC	241	if (prz->corrected_bytes \|\| prz->bad_blocks)
	242	ret = snprintf(str, len, ""
	243	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	244	prz->corrected_bytes, prz->bad_blocks);
	245	else
	246	ret = snprintf(str, len, "\nNo errors detected\n");
	247
	248	return ret;
	249	}
	250
a15d0b36	251	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	252	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	253	{
9cc05ad9 CC	254	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	255	memcpy(buffer->data + start, s, count);
808d0387 CC	256	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	257	}
9cc05ad9 CC	258
201e4aca	259	void persistent_ram_save_old(struct persistent_ram_zone *prz)
9cc05ad9 CC	260	{
9cc05ad9 CC	261	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	262	size_t size = buffer_size(prz);
808d0387 CC	263	size_t start = buffer_start(prz);
9cc05ad9	264
201e4aca AV	265	if (!size)
201e4aca AV	266	return;
c672528a	267
201e4aca AV	268	if (!prz->old_log) {
	269	persistent_ram_ecc_old(prz);
	270	prz->old_log = kmalloc(size, GFP_KERNEL);
	271	}
	272	if (!prz->old_log) {
c672528a CC	273	pr_err("persistent_ram: failed to allocate buffer\n");
	274	return;
	275	}
	276
808d0387 CC	277	prz->old_log_size = size;
	278	memcpy(prz->old_log, &buffer->data[start], size - start);
	279	memcpy(prz->old_log + size - start, &buffer->data[0], start);
c672528a CC	280	}
c672528a CC	281
a15d0b36	282	int notrace persistent_ram_write(struct persistent_ram_zone *prz,
c672528a CC	283	const void *s, unsigned int count)
	284	{
	285	int rem;
	286	int c = count;
808d0387	287	size_t start;
c672528a	288
808d0387	289	if (unlikely(c > prz->buffer_size)) {
c672528a CC	290	s += c - prz->buffer_size;
	291	c = prz->buffer_size;
	292	}
808d0387	293
484dd30e	294	buffer_size_add(prz, c);
808d0387 CC	295
	296	start = buffer_start_add(prz, c);
	297
	298	rem = prz->buffer_size - start;
	299	if (unlikely(rem < c)) {
	300	persistent_ram_update(prz, s, start, rem);
c672528a CC	301	s += rem;
c672528a CC	302	c -= rem;
808d0387	303	start = 0;
c672528a	304	}
808d0387	305	persistent_ram_update(prz, s, start, c);
c672528a	306
9cc05ad9	307	persistent_ram_update_header_ecc(prz);
c672528a CC	308
	309	return count;
	310	}
	311
c672528a CC	312	size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
	313	{
	314	return prz->old_log_size;
	315	}
	316
	317	void persistent_ram_old(struct persistent_ram_zone prz)
	318	{
	319	return prz->old_log;
	320	}
	321
	322	void persistent_ram_free_old(struct persistent_ram_zone *prz)
	323	{
	324	kfree(prz->old_log);
	325	prz->old_log = NULL;
	326	prz->old_log_size = 0;
	327	}
	328
fce39793 AV	329	void persistent_ram_zap(struct persistent_ram_zone *prz)
	330	{
	331	atomic_set(&prz->buffer->start, 0);
	332	atomic_set(&prz->buffer->size, 0);
	333	persistent_ram_update_header_ecc(prz);
	334	}
	335
2b1321e4	336	static void *persistent_ram_vmap(phys_addr_t start, size_t size)
c672528a	337	{
404a6043 CC	338	struct page **pages;
	339	phys_addr_t page_start;
	340	unsigned int page_count;
	341	pgprot_t prot;
	342	unsigned int i;
2b1321e4	343	void *vaddr;
404a6043 CC	344
	345	page_start = start - offset_in_page(start);
	346	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	347
	348	prot = pgprot_noncached(PAGE_KERNEL);
	349
	350	pages = kmalloc(sizeof(struct page ) page_count, GFP_KERNEL);
	351	if (!pages) {
	352	pr_err("%s: Failed to allocate array for %u pages\n", __func__,
	353	page_count);
2b1321e4	354	return NULL;
404a6043 CC	355	}
	356
	357	for (i = 0; i < page_count; i++) {
	358	phys_addr_t addr = page_start + i * PAGE_SIZE;
	359	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	360	}
2b1321e4	361	vaddr = vmap(pages, page_count, VM_MAP, prot);
404a6043	362	kfree(pages);
2b1321e4 AV	363
	364	return vaddr;
	365	}
	366
24c3d2f3 AV	367	static void *persistent_ram_iomap(phys_addr_t start, size_t size)
	368	{
	369	if (!request_mem_region(start, size, "persistent_ram")) {
	370	pr_err("request mem region (0x%llx@0x%llx) failed\n",
	371	(unsigned long long)size, (unsigned long long)start);
	372	return NULL;
	373	}
	374
	375	return ioremap(start, size);
	376	}
	377
2b1321e4 AV	378	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
	379	struct persistent_ram_zone *prz)
	380	{
d3b48769 AV	381	prz->paddr = start;
	382	prz->size = size;
	383
24c3d2f3 AV	384	if (pfn_valid(start >> PAGE_SHIFT))
	385	prz->vaddr = persistent_ram_vmap(start, size);
	386	else
	387	prz->vaddr = persistent_ram_iomap(start, size);
	388
404a6043	389	if (!prz->vaddr) {
2b1321e4 AV	390	pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
2b1321e4 AV	391	(unsigned long long)size, (unsigned long long)start);
404a6043 CC	392	return -ENOMEM;
	393	}
	394
	395	prz->buffer = prz->vaddr + offset_in_page(start);
	396	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	397
	398	return 0;
	399	}
	400
f568f6ca	401	static int persistent_ram_post_init(struct persistent_ram_zone *prz, u32 sig,
c31ad081	402	struct persistent_ram_ecc_info *ecc_info)
404a6043	403	{
bb4206f2	404	int ret;
c672528a	405
c31ad081	406	ret = persistent_ram_init_ecc(prz, ecc_info);
9cc05ad9	407	if (ret)
bb4206f2	408	return ret;
c672528a	409
cbe7cbf5 AV	410	sig ^= PERSISTENT_RAM_SIG;
	411
	412	if (prz->buffer->sig == sig) {
808d0387 CC	413	if (buffer_size(prz) > prz->buffer_size \|\|
	414	buffer_start(prz) > buffer_size(prz))
	415	pr_info("persistent_ram: found existing invalid buffer,"
f56d711b	416	" size %zu, start %zu\n",
808d0387	417	buffer_size(prz), buffer_start(prz));
c672528a	418	else {
602b5be4	419	pr_debug("persistent_ram: found existing buffer,"
f56d711b	420	" size %zu, start %zu\n",
808d0387	421	buffer_size(prz), buffer_start(prz));
c672528a	422	persistent_ram_save_old(prz);
25b63da6	423	return 0;
c672528a CC	424	}
c672528a CC	425	} else {
602b5be4	426	pr_debug("persistent_ram: no valid data in buffer"
808d0387	427	" (sig = 0x%08x)\n", prz->buffer->sig);
c672528a CC	428	}
c672528a CC	429
cbe7cbf5	430	prz->buffer->sig = sig;
fce39793	431	persistent_ram_zap(prz);
c672528a	432
bb4206f2 AV	433	return 0;
	434	}
	435
d3b48769 AV	436	void persistent_ram_free(struct persistent_ram_zone *prz)
d3b48769 AV	437	{
beeb9432 AV	438	if (!prz)
	439	return;
	440
	441	if (prz->vaddr) {
	442	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
	443	vunmap(prz->vaddr);
	444	} else {
	445	iounmap(prz->vaddr);
	446	release_mem_region(prz->paddr, prz->size);
	447	}
	448	prz->vaddr = NULL;
d3b48769 AV	449	}
	450	persistent_ram_free_old(prz);
	451	kfree(prz);
	452	}
	453
f568f6ca	454	struct persistent_ram_zone *persistent_ram_new(phys_addr_t start, size_t size,
c31ad081	455	u32 sig, struct persistent_ram_ecc_info *ecc_info)
8cf5aff8 AV	456	{
	457	struct persistent_ram_zone *prz;
	458	int ret = -ENOMEM;
	459
	460	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	461	if (!prz) {
	462	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	463	goto err;
	464	}
	465
	466	ret = persistent_ram_buffer_map(start, size, prz);
	467	if (ret)
	468	goto err;
	469
c31ad081	470	ret = persistent_ram_post_init(prz, sig, ecc_info);
beeb9432 AV	471	if (ret)
beeb9432 AV	472	goto err;
8cf5aff8 AV	473
	474	return prz;
	475	err:
beeb9432	476	persistent_ram_free(prz);
8cf5aff8 AV	477	return ERR_PTR(ret);
8cf5aff8 AV	478	}