[deliverable/linux.git] / drivers / staging / android / persistent_ram.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 "persistent_ram.h"

struct persistent_ram_buffer {
	uint32_t    sig;
	atomic_t    start;
	atomic_t    size;
	uint8_t     data[0];
};

#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */

static __initdata LIST_HEAD(persistent_ram_list);

static inline size_t buffer_size(struct persistent_ram_zone *prz)
{
	return atomic_read(&prz->buffer->size);
}

static inline size_t buffer_start(struct persistent_ram_zone *prz)
{
	return atomic_read(&prz->buffer->start);
}

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

	do {
		old = atomic_read(&prz->buffer->start);
		new = old + a;
		while (unlikely(new > prz->buffer_size))
			new -= prz->buffer_size;
	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);

	return old;
}

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

	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
		return;

	do {
		old = atomic_read(&prz->buffer->size);
		new = old + a;
		if (new > prz->buffer_size)
			new = prz->buffer_size;
	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
}

/* increase the size counter, retuning an error if it hits the max size */
static inline ssize_t buffer_size_add_clamp(struct persistent_ram_zone *prz,
	size_t a)
{
	size_t old;
	size_t new;

	do {
		old = atomic_read(&prz->buffer->size);
		new = old + a;
		if (new > prz->buffer_size)
			return -ENOMEM;
	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);

	return 0;
}

static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
	uint8_t *data, size_t len, uint8_t *ecc)
{
	int i;
	uint16_t par[prz->ecc_size];

	/* Initialize the parity buffer */
	memset(par, 0, sizeof(par));
	encode_rs8(prz->rs_decoder, data, len, par, 0);
	for (i = 0; i < prz->ecc_size; i++)
		ecc[i] = par[i];
}

static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	void *data, size_t len, uint8_t *ecc)
{
	int i;
	uint16_t par[prz->ecc_size];

	for (i = 0; i < prz->ecc_size; i++)
		par[i] = ecc[i];
	return decode_rs8(prz->rs_decoder, data, par, len,
				NULL, 0, NULL, 0, NULL);
}

static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
	unsigned int start, unsigned int count)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	uint8_t *block;
	uint8_t *par;
	int ecc_block_size = prz->ecc_block_size;
	int ecc_size = prz->ecc_size;
	int size = prz->ecc_block_size;

	if (!prz->ecc)
		return;

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

	do {
		if (block + ecc_block_size > buffer_end)
			size = buffer_end - block;
		persistent_ram_encode_rs8(prz, block, size, par);
		block += ecc_block_size;
		par += ecc_size;
	} while (block < buffer->data + start + count);
}

static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
{
	struct persistent_ram_buffer *buffer = prz->buffer;

	if (!prz->ecc)
		return;

	persistent_ram_encode_rs8(prz, (uint8_t *)buffer, sizeof(*buffer),
				  prz->par_header);
}

static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	uint8_t *block;
	uint8_t *par;

	if (!prz->ecc)
		return;

	block = buffer->data;
	par = prz->par_buffer;
	while (block < buffer->data + buffer_size(prz)) {
		int numerr;
		int size = prz->ecc_block_size;
		if (block + size > buffer->data + prz->buffer_size)
			size = buffer->data + prz->buffer_size - block;
		numerr = persistent_ram_decode_rs8(prz, block, size, par);
		if (numerr > 0) {
			pr_devel("persistent_ram: error in block %p, %d\n",
			       block, numerr);
			prz->corrected_bytes += numerr;
		} else if (numerr < 0) {
			pr_devel("persistent_ram: uncorrectable error in block %p\n",
				block);
			prz->bad_blocks++;
		}
		block += prz->ecc_block_size;
		par += prz->ecc_size;
	}
}

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

	if (!prz->ecc)
		return 0;

	prz->ecc_block_size = 128;
	prz->ecc_size = 16;
	prz->ecc_symsize = 8;
	prz->ecc_poly = 0x11d;

	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
	prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;

	if (prz->buffer_size > buffer_size) {
		pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
		       buffer_size, prz->buffer_size);
		return -EINVAL;
	}

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

	/*
	 * first consecutive root is 0
	 * primitive element to generate roots = 1
	 */
	prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
				  prz->ecc_size);
	if (prz->rs_decoder == NULL) {
		pr_info("persistent_ram: init_rs failed\n");
		return -EINVAL;
	}

	prz->corrected_bytes = 0;
	prz->bad_blocks = 0;

	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
					   prz->par_header);
	if (numerr > 0) {
		pr_info("persistent_ram: error in header, %d\n", numerr);
		prz->corrected_bytes += numerr;
	} else if (numerr < 0) {
		pr_info("persistent_ram: uncorrectable error in header\n");
		prz->bad_blocks++;
	}

	return 0;
}

ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	char *str, size_t len)
{
	ssize_t ret;

	if (prz->corrected_bytes || prz->bad_blocks)
		ret = snprintf(str, len, ""
			"\n%d Corrected bytes, %d unrecoverable blocks\n",
			prz->corrected_bytes, prz->bad_blocks);
	else
		ret = snprintf(str, len, "\nNo errors detected\n");

	return ret;
}

static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
	const void *s, unsigned int start, unsigned int count)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	memcpy(buffer->data + start, s, count);
	persistent_ram_update_ecc(prz, start, count);
}

static void __init
persistent_ram_save_old(struct persistent_ram_zone *prz)
{
	struct persistent_ram_buffer *buffer = prz->buffer;
	size_t size = buffer_size(prz);
	size_t start = buffer_start(prz);
	char *dest;

	persistent_ram_ecc_old(prz);

	dest = kmalloc(size, GFP_KERNEL);
	if (dest == NULL) {
		pr_err("persistent_ram: failed to allocate buffer\n");
		return;
	}

	prz->old_log = dest;
	prz->old_log_size = size;
	memcpy(prz->old_log, &buffer->data[start], size - start);
	memcpy(prz->old_log + size - start, &buffer->data[0], start);
}

int notrace persistent_ram_write(struct persistent_ram_zone *prz,
	const void *s, unsigned int count)
{
	int rem;
	int c = count;
	size_t start;

	if (unlikely(c > prz->buffer_size)) {
		s += c - prz->buffer_size;
		c = prz->buffer_size;
	}

	buffer_size_add_clamp(prz, c);

	start = buffer_start_add(prz, c);

	rem = prz->buffer_size - start;
	if (unlikely(rem < c)) {
		persistent_ram_update(prz, s, start, rem);
		s += rem;
		c -= rem;
		start = 0;
	}
	persistent_ram_update(prz, s, start, c);

	persistent_ram_update_header_ecc(prz);

	return count;
}

size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
{
	return prz->old_log_size;
}

void *persistent_ram_old(struct persistent_ram_zone *prz)
{
	return prz->old_log;
}

void persistent_ram_free_old(struct persistent_ram_zone *prz)
{
	kfree(prz->old_log);
	prz->old_log = NULL;
	prz->old_log_size = 0;
}

static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
		struct persistent_ram_zone *prz)
{
	struct page **pages;
	phys_addr_t page_start;
	unsigned int page_count;
	pgprot_t prot;
	unsigned int i;

	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 -ENOMEM;
	}

	for (i = 0; i < page_count; i++) {
		phys_addr_t addr = page_start + i * PAGE_SIZE;
		pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	}
	prz->vaddr = vmap(pages, page_count, VM_MAP, prot);
	kfree(pages);
	if (!prz->vaddr) {
		pr_err("%s: Failed to map %u pages\n", __func__, page_count);
		return -ENOMEM;
	}

	prz->buffer = prz->vaddr + offset_in_page(start);
	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);

	return 0;
}

static int __init persistent_ram_buffer_init(const char *name,
		struct persistent_ram_zone *prz)
{
	int i;
	struct persistent_ram *ram;
	struct persistent_ram_descriptor *desc;
	phys_addr_t start;

	list_for_each_entry(ram, &persistent_ram_list, node) {
		start = ram->start;
		for (i = 0; i < ram->num_descs; i++) {
			desc = &ram->descs[i];
			if (!strcmp(desc->name, name))
				return persistent_ram_buffer_map(start,
						desc->size, prz);
			start += desc->size;
		}
	}

	return -EINVAL;
}

static  __init
struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc)
{
	struct persistent_ram_zone *prz;
	int ret = -ENOMEM;

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

	ret = persistent_ram_buffer_init(dev_name(dev), prz);
	if (ret) {
		pr_err("persistent_ram: failed to initialize buffer\n");
		goto err;
	}

	prz->ecc = ecc;
	ret = persistent_ram_init_ecc(prz, prz->buffer_size);
	if (ret)
		goto err;

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

	prz->buffer->sig = PERSISTENT_RAM_SIG;
	atomic_set(&prz->buffer->start, 0);
	atomic_set(&prz->buffer->size, 0);

	return prz;
err:
	kfree(prz);
	return ERR_PTR(ret);
}

struct persistent_ram_zone * __init
persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
{
	return __persistent_ram_init(dev, ecc);
}

int __init persistent_ram_early_init(struct persistent_ram *ram)
{
	int ret;

	ret = memblock_reserve(ram->start, ram->size);
	if (ret) {
		pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
			(long)ram->start, (long)(ram->start + ram->size - 1));
		return ret;
	}

	list_add_tail(&ram->node, &persistent_ram_list);

	pr_info("Initialized persistent memory from %08lx-%08lx\n",
		(long)ram->start, (long)(ram->start + ram->size - 1));

	return 0;
}
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>
c672528a CC	26	#include "persistent_ram.h"
c672528a CC	27
c672528a CC	28	struct persistent_ram_buffer {
c672528a CC	29	uint32_t sig;
808d0387 CC	30	atomic_t start;
808d0387 CC	31	atomic_t size;
c672528a CC	32	uint8_t data[0];
	33	};
	34
	35	#define PERSISTENT_RAM_SIG (0x43474244) /* DBGC */
	36
404a6043	37	static __initdata LIST_HEAD(persistent_ram_list);
c672528a	38
808d0387 CC	39	static inline size_t buffer_size(struct persistent_ram_zone *prz)
	40	{
	41	return atomic_read(&prz->buffer->size);
	42	}
	43
	44	static inline size_t buffer_start(struct persistent_ram_zone *prz)
	45	{
	46	return atomic_read(&prz->buffer->start);
	47	}
	48
	49	/* increase and wrap the start pointer, returning the old value */
	50	static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
	51	{
	52	int old;
	53	int new;
	54
	55	do {
	56	old = atomic_read(&prz->buffer->start);
	57	new = old + a;
	58	while (unlikely(new > prz->buffer_size))
	59	new -= prz->buffer_size;
	60	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
	61
	62	return old;
	63	}
	64
	65	/* increase the size counter until it hits the max size */
	66	static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
	67	{
	68	size_t old;
	69	size_t new;
	70
	71	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
	72	return;
	73
	74	do {
	75	old = atomic_read(&prz->buffer->size);
	76	new = old + a;
	77	if (new > prz->buffer_size)
	78	new = prz->buffer_size;
	79	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
	80	}
	81
	82	/* increase the size counter, retuning an error if it hits the max size */
	83	static inline ssize_t buffer_size_add_clamp(struct persistent_ram_zone *prz,
	84	size_t a)
	85	{
	86	size_t old;
	87	size_t new;
	88
	89	do {
	90	old = atomic_read(&prz->buffer->size);
	91	new = old + a;
	92	if (new > prz->buffer_size)
	93	return -ENOMEM;
	94	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
	95
	96	return 0;
	97	}
	98
a15d0b36	99	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	100	uint8_t data, size_t len, uint8_t ecc)
	101	{
	102	int i;
9cc05ad9 CC	103	uint16_t par[prz->ecc_size];
9cc05ad9 CC	104
c672528a CC	105	/* Initialize the parity buffer */
	106	memset(par, 0, sizeof(par));
	107	encode_rs8(prz->rs_decoder, data, len, par, 0);
9cc05ad9	108	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	109	ecc[i] = par[i];
	110	}
	111
	112	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	113	void data, size_t len, uint8_t ecc)
	114	{
	115	int i;
9cc05ad9 CC	116	uint16_t par[prz->ecc_size];
	117
	118	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	119	par[i] = ecc[i];
	120	return decode_rs8(prz->rs_decoder, data, par, len,
	121	NULL, 0, NULL, 0, NULL);
	122	}
c672528a	123
a15d0b36	124	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	125	unsigned int start, unsigned int count)
c672528a CC	126	{
c672528a CC	127	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	128	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	129	uint8_t *block;
	130	uint8_t *par;
9cc05ad9 CC	131	int ecc_block_size = prz->ecc_block_size;
	132	int ecc_size = prz->ecc_size;
	133	int size = prz->ecc_block_size;
	134
	135	if (!prz->ecc)
	136	return;
	137
808d0387 CC	138	block = buffer->data + (start & ~(ecc_block_size - 1));
	139	par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
	140
c672528a	141	do {
9cc05ad9	142	if (block + ecc_block_size > buffer_end)
c672528a CC	143	size = buffer_end - block;
c672528a CC	144	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	145	block += ecc_block_size;
9cc05ad9 CC	146	par += ecc_size;
808d0387	147	} while (block < buffer->data + start + count);
c672528a CC	148	}
c672528a CC	149
9cc05ad9	150	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	151	{
c672528a CC	152	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	153
9cc05ad9 CC	154	if (!prz->ecc)
	155	return;
	156
c672528a CC	157	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	158	prz->par_header);
c672528a CC	159	}
c672528a CC	160
9cc05ad9	161	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	162	{
c672528a CC	163	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	164	uint8_t *block;
	165	uint8_t *par;
	166
9cc05ad9 CC	167	if (!prz->ecc)
	168	return;
	169
c672528a CC	170	block = buffer->data;
c672528a CC	171	par = prz->par_buffer;
808d0387	172	while (block < buffer->data + buffer_size(prz)) {
c672528a	173	int numerr;
9cc05ad9	174	int size = prz->ecc_block_size;
c672528a CC	175	if (block + size > buffer->data + prz->buffer_size)
	176	size = buffer->data + prz->buffer_size - block;
	177	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	178	if (numerr > 0) {
9cc05ad9	179	pr_devel("persistent_ram: error in block %p, %d\n",
c672528a	180	block, numerr);
c672528a CC	181	prz->corrected_bytes += numerr;
c672528a CC	182	} else if (numerr < 0) {
9cc05ad9	183	pr_devel("persistent_ram: uncorrectable error in block %p\n",
c672528a	184	block);
c672528a CC	185	prz->bad_blocks++;
c672528a CC	186	}
9cc05ad9 CC	187	block += prz->ecc_block_size;
	188	par += prz->ecc_size;
	189	}
	190	}
	191
	192	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
	193	size_t buffer_size)
	194	{
	195	int numerr;
	196	struct persistent_ram_buffer *buffer = prz->buffer;
	197	int ecc_blocks;
	198
	199	if (!prz->ecc)
	200	return 0;
	201
	202	prz->ecc_block_size = 128;
	203	prz->ecc_size = 16;
	204	prz->ecc_symsize = 8;
	205	prz->ecc_poly = 0x11d;
	206
	207	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
	208	prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
	209
	210	if (prz->buffer_size > buffer_size) {
	211	pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
	212	buffer_size, prz->buffer_size);
	213	return -EINVAL;
	214	}
	215
	216	prz->par_buffer = buffer->data + prz->buffer_size;
	217	prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
	218
	219	/*
	220	* first consecutive root is 0
	221	* primitive element to generate roots = 1
	222	*/
	223	prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
	224	prz->ecc_size);
	225	if (prz->rs_decoder == NULL) {
	226	pr_info("persistent_ram: init_rs failed\n");
	227	return -EINVAL;
c672528a	228	}
9cc05ad9 CC	229
	230	prz->corrected_bytes = 0;
	231	prz->bad_blocks = 0;
	232
	233	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	234	prz->par_header);
	235	if (numerr > 0) {
	236	pr_info("persistent_ram: error in header, %d\n", numerr);
	237	prz->corrected_bytes += numerr;
	238	} else if (numerr < 0) {
	239	pr_info("persistent_ram: uncorrectable error in header\n");
	240	prz->bad_blocks++;
	241	}
	242
	243	return 0;
	244	}
	245
	246	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	247	char *str, size_t len)
	248	{
	249	ssize_t ret;
	250
	251	if (prz->corrected_bytes \|\| prz->bad_blocks)
	252	ret = snprintf(str, len, ""
	253	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	254	prz->corrected_bytes, prz->bad_blocks);
	255	else
	256	ret = snprintf(str, len, "\nNo errors detected\n");
	257
	258	return ret;
	259	}
	260
a15d0b36	261	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	262	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	263	{
9cc05ad9 CC	264	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	265	memcpy(buffer->data + start, s, count);
808d0387 CC	266	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	267	}
	268
	269	static void __init
	270	persistent_ram_save_old(struct persistent_ram_zone *prz)
	271	{
	272	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	273	size_t size = buffer_size(prz);
808d0387 CC	274	size_t start = buffer_start(prz);
9cc05ad9 CC	275	char *dest;
	276
	277	persistent_ram_ecc_old(prz);
c672528a	278
808d0387	279	dest = kmalloc(size, GFP_KERNEL);
c672528a CC	280	if (dest == NULL) {
	281	pr_err("persistent_ram: failed to allocate buffer\n");
	282	return;
	283	}
	284
	285	prz->old_log = dest;
808d0387 CC	286	prz->old_log_size = size;
	287	memcpy(prz->old_log, &buffer->data[start], size - start);
	288	memcpy(prz->old_log + size - start, &buffer->data[0], start);
c672528a CC	289	}
c672528a CC	290
a15d0b36	291	int notrace persistent_ram_write(struct persistent_ram_zone *prz,
c672528a CC	292	const void *s, unsigned int count)
	293	{
	294	int rem;
	295	int c = count;
808d0387	296	size_t start;
c672528a	297
808d0387	298	if (unlikely(c > prz->buffer_size)) {
c672528a CC	299	s += c - prz->buffer_size;
	300	c = prz->buffer_size;
	301	}
808d0387 CC	302
	303	buffer_size_add_clamp(prz, c);
	304
	305	start = buffer_start_add(prz, c);
	306
	307	rem = prz->buffer_size - start;
	308	if (unlikely(rem < c)) {
	309	persistent_ram_update(prz, s, start, rem);
c672528a CC	310	s += rem;
c672528a CC	311	c -= rem;
808d0387	312	start = 0;
c672528a	313	}
808d0387	314	persistent_ram_update(prz, s, start, c);
c672528a	315
9cc05ad9	316	persistent_ram_update_header_ecc(prz);
c672528a CC	317
	318	return count;
	319	}
	320
c672528a CC	321	size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
	322	{
	323	return prz->old_log_size;
	324	}
	325
	326	void persistent_ram_old(struct persistent_ram_zone prz)
	327	{
	328	return prz->old_log;
	329	}
	330
	331	void persistent_ram_free_old(struct persistent_ram_zone *prz)
	332	{
	333	kfree(prz->old_log);
	334	prz->old_log = NULL;
	335	prz->old_log_size = 0;
	336	}
	337
404a6043 CC	338	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
404a6043 CC	339	struct persistent_ram_zone *prz)
c672528a	340	{
404a6043 CC	341	struct page **pages;
	342	phys_addr_t page_start;
	343	unsigned int page_count;
	344	pgprot_t prot;
	345	unsigned int i;
	346
	347	page_start = start - offset_in_page(start);
	348	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	349
	350	prot = pgprot_noncached(PAGE_KERNEL);
	351
	352	pages = kmalloc(sizeof(struct page ) page_count, GFP_KERNEL);
	353	if (!pages) {
	354	pr_err("%s: Failed to allocate array for %u pages\n", __func__,
	355	page_count);
	356	return -ENOMEM;
	357	}
	358
	359	for (i = 0; i < page_count; i++) {
	360	phys_addr_t addr = page_start + i * PAGE_SIZE;
	361	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	362	}
	363	prz->vaddr = vmap(pages, page_count, VM_MAP, prot);
	364	kfree(pages);
	365	if (!prz->vaddr) {
	366	pr_err("%s: Failed to map %u pages\n", __func__, page_count);
	367	return -ENOMEM;
	368	}
	369
	370	prz->buffer = prz->vaddr + offset_in_page(start);
	371	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	372
	373	return 0;
	374	}
	375
	376	static int __init persistent_ram_buffer_init(const char *name,
	377	struct persistent_ram_zone *prz)
	378	{
	379	int i;
	380	struct persistent_ram *ram;
	381	struct persistent_ram_descriptor *desc;
	382	phys_addr_t start;
	383
	384	list_for_each_entry(ram, &persistent_ram_list, node) {
	385	start = ram->start;
	386	for (i = 0; i < ram->num_descs; i++) {
	387	desc = &ram->descs[i];
	388	if (!strcmp(desc->name, name))
	389	return persistent_ram_buffer_map(start,
	390	desc->size, prz);
	391	start += desc->size;
	392	}
	393	}
	394
	395	return -EINVAL;
	396	}
	397
	398	static __init
	399	struct persistent_ram_zone __persistent_ram_init(struct device dev, bool ecc)
	400	{
	401	struct persistent_ram_zone *prz;
474a8988	402	int ret = -ENOMEM;
c672528a	403
404a6043 CC	404	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	405	if (!prz) {
	406	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
474a8988	407	goto err;
404a6043	408	}
c672528a	409
404a6043 CC	410	ret = persistent_ram_buffer_init(dev_name(dev), prz);
	411	if (ret) {
	412	pr_err("persistent_ram: failed to initialize buffer\n");
474a8988	413	goto err;
c672528a CC	414	}
c672528a CC	415
9cc05ad9	416	prz->ecc = ecc;
404a6043	417	ret = persistent_ram_init_ecc(prz, prz->buffer_size);
9cc05ad9	418	if (ret)
474a8988	419	goto err;
c672528a	420
404a6043	421	if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
808d0387 CC	422	if (buffer_size(prz) > prz->buffer_size \|\|
	423	buffer_start(prz) > buffer_size(prz))
	424	pr_info("persistent_ram: found existing invalid buffer,"
f56d711b	425	" size %zu, start %zu\n",
808d0387	426	buffer_size(prz), buffer_start(prz));
c672528a	427	else {
808d0387	428	pr_info("persistent_ram: found existing buffer,"
f56d711b	429	" size %zu, start %zu\n",
808d0387	430	buffer_size(prz), buffer_start(prz));
c672528a CC	431	persistent_ram_save_old(prz);
	432	}
	433	} else {
808d0387 CC	434	pr_info("persistent_ram: no valid data in buffer"
808d0387 CC	435	" (sig = 0x%08x)\n", prz->buffer->sig);
c672528a CC	436	}
c672528a CC	437
404a6043	438	prz->buffer->sig = PERSISTENT_RAM_SIG;
808d0387 CC	439	atomic_set(&prz->buffer->start, 0);
808d0387 CC	440	atomic_set(&prz->buffer->size, 0);
c672528a	441
404a6043	442	return prz;
474a8988 JJ	443	err:
	444	kfree(prz);
	445	return ERR_PTR(ret);
404a6043	446	}
c672528a	447
404a6043 CC	448	struct persistent_ram_zone * __init
	449	persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
	450	{
	451	return __persistent_ram_init(dev, ecc);
c672528a CC	452	}
c672528a CC	453
404a6043	454	int __init persistent_ram_early_init(struct persistent_ram *ram)
c672528a	455	{
404a6043 CC	456	int ret;
	457
	458	ret = memblock_reserve(ram->start, ram->size);
	459	if (ret) {
	460	pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
	461	(long)ram->start, (long)(ram->start + ram->size - 1));
	462	return ret;
	463	}
	464
	465	list_add_tail(&ram->node, &persistent_ram_list);
	466
	467	pr_info("Initialized persistent memory from %08lx-%08lx\n",
	468	(long)ram->start, (long)(ram->start + ram->size - 1));
	469
	470	return 0;
c672528a	471	}