[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);
}

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(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 int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
{
	int ret;

	prz->ecc = ecc;

	ret = persistent_ram_init_ecc(prz, prz->buffer_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_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 0;
}

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;
	}

	persistent_ram_post_init(prz, ecc);

	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
a15d0b36	82	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	83	uint8_t data, size_t len, uint8_t ecc)
	84	{
	85	int i;
9cc05ad9 CC	86	uint16_t par[prz->ecc_size];
9cc05ad9 CC	87
c672528a CC	88	/* Initialize the parity buffer */
	89	memset(par, 0, sizeof(par));
	90	encode_rs8(prz->rs_decoder, data, len, par, 0);
9cc05ad9	91	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	92	ecc[i] = par[i];
	93	}
	94
	95	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	96	void data, size_t len, uint8_t ecc)
	97	{
	98	int i;
9cc05ad9 CC	99	uint16_t par[prz->ecc_size];
	100
	101	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	102	par[i] = ecc[i];
	103	return decode_rs8(prz->rs_decoder, data, par, len,
	104	NULL, 0, NULL, 0, NULL);
	105	}
c672528a	106
a15d0b36	107	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	108	unsigned int start, unsigned int count)
c672528a CC	109	{
c672528a CC	110	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	111	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	112	uint8_t *block;
	113	uint8_t *par;
9cc05ad9 CC	114	int ecc_block_size = prz->ecc_block_size;
	115	int ecc_size = prz->ecc_size;
	116	int size = prz->ecc_block_size;
	117
	118	if (!prz->ecc)
	119	return;
	120
808d0387 CC	121	block = buffer->data + (start & ~(ecc_block_size - 1));
	122	par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
	123
c672528a	124	do {
9cc05ad9	125	if (block + ecc_block_size > buffer_end)
c672528a CC	126	size = buffer_end - block;
c672528a CC	127	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	128	block += ecc_block_size;
9cc05ad9 CC	129	par += ecc_size;
808d0387	130	} while (block < buffer->data + start + count);
c672528a CC	131	}
c672528a CC	132
9cc05ad9	133	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	134	{
c672528a CC	135	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	136
9cc05ad9 CC	137	if (!prz->ecc)
	138	return;
	139
c672528a CC	140	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	141	prz->par_header);
c672528a CC	142	}
c672528a CC	143
9cc05ad9	144	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	145	{
c672528a CC	146	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	147	uint8_t *block;
	148	uint8_t *par;
	149
9cc05ad9 CC	150	if (!prz->ecc)
	151	return;
	152
c672528a CC	153	block = buffer->data;
c672528a CC	154	par = prz->par_buffer;
808d0387	155	while (block < buffer->data + buffer_size(prz)) {
c672528a	156	int numerr;
9cc05ad9	157	int size = prz->ecc_block_size;
c672528a CC	158	if (block + size > buffer->data + prz->buffer_size)
	159	size = buffer->data + prz->buffer_size - block;
	160	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	161	if (numerr > 0) {
9cc05ad9	162	pr_devel("persistent_ram: error in block %p, %d\n",
c672528a	163	block, numerr);
c672528a CC	164	prz->corrected_bytes += numerr;
c672528a CC	165	} else if (numerr < 0) {
9cc05ad9	166	pr_devel("persistent_ram: uncorrectable error in block %p\n",
c672528a	167	block);
c672528a CC	168	prz->bad_blocks++;
c672528a CC	169	}
9cc05ad9 CC	170	block += prz->ecc_block_size;
	171	par += prz->ecc_size;
	172	}
	173	}
	174
	175	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
	176	size_t buffer_size)
	177	{
	178	int numerr;
	179	struct persistent_ram_buffer *buffer = prz->buffer;
	180	int ecc_blocks;
	181
	182	if (!prz->ecc)
	183	return 0;
	184
	185	prz->ecc_block_size = 128;
	186	prz->ecc_size = 16;
	187	prz->ecc_symsize = 8;
	188	prz->ecc_poly = 0x11d;
	189
	190	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
	191	prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
	192
	193	if (prz->buffer_size > buffer_size) {
	194	pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
	195	buffer_size, prz->buffer_size);
	196	return -EINVAL;
	197	}
	198
	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	*/
	206	prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
	207	prz->ecc_size);
	208	if (prz->rs_decoder == NULL) {
	209	pr_info("persistent_ram: init_rs failed\n");
	210	return -EINVAL;
c672528a	211	}
9cc05ad9 CC	212
	213	prz->corrected_bytes = 0;
	214	prz->bad_blocks = 0;
	215
	216	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	217	prz->par_header);
	218	if (numerr > 0) {
	219	pr_info("persistent_ram: error in header, %d\n", numerr);
	220	prz->corrected_bytes += numerr;
	221	} else if (numerr < 0) {
	222	pr_info("persistent_ram: uncorrectable error in header\n");
	223	prz->bad_blocks++;
	224	}
	225
	226	return 0;
	227	}
	228
	229	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	230	char *str, size_t len)
	231	{
	232	ssize_t ret;
	233
	234	if (prz->corrected_bytes \|\| prz->bad_blocks)
	235	ret = snprintf(str, len, ""
	236	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	237	prz->corrected_bytes, prz->bad_blocks);
	238	else
	239	ret = snprintf(str, len, "\nNo errors detected\n");
	240
	241	return ret;
	242	}
	243
a15d0b36	244	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	245	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	246	{
9cc05ad9 CC	247	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	248	memcpy(buffer->data + start, s, count);
808d0387 CC	249	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	250	}
	251
	252	static void __init
	253	persistent_ram_save_old(struct persistent_ram_zone *prz)
	254	{
	255	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	256	size_t size = buffer_size(prz);
808d0387 CC	257	size_t start = buffer_start(prz);
9cc05ad9 CC	258	char *dest;
	259
	260	persistent_ram_ecc_old(prz);
c672528a	261
808d0387	262	dest = kmalloc(size, GFP_KERNEL);
c672528a CC	263	if (dest == NULL) {
	264	pr_err("persistent_ram: failed to allocate buffer\n");
	265	return;
	266	}
	267
	268	prz->old_log = dest;
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
404a6043 CC	321	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
404a6043 CC	322	struct persistent_ram_zone *prz)
c672528a	323	{
404a6043 CC	324	struct page **pages;
	325	phys_addr_t page_start;
	326	unsigned int page_count;
	327	pgprot_t prot;
	328	unsigned int i;
	329
	330	page_start = start - offset_in_page(start);
	331	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	332
	333	prot = pgprot_noncached(PAGE_KERNEL);
	334
	335	pages = kmalloc(sizeof(struct page ) page_count, GFP_KERNEL);
	336	if (!pages) {
	337	pr_err("%s: Failed to allocate array for %u pages\n", __func__,
	338	page_count);
	339	return -ENOMEM;
	340	}
	341
	342	for (i = 0; i < page_count; i++) {
	343	phys_addr_t addr = page_start + i * PAGE_SIZE;
	344	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	345	}
	346	prz->vaddr = vmap(pages, page_count, VM_MAP, prot);
	347	kfree(pages);
	348	if (!prz->vaddr) {
	349	pr_err("%s: Failed to map %u pages\n", __func__, page_count);
	350	return -ENOMEM;
	351	}
	352
	353	prz->buffer = prz->vaddr + offset_in_page(start);
	354	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	355
	356	return 0;
	357	}
	358
	359	static int __init persistent_ram_buffer_init(const char *name,
	360	struct persistent_ram_zone *prz)
	361	{
	362	int i;
	363	struct persistent_ram *ram;
	364	struct persistent_ram_descriptor *desc;
	365	phys_addr_t start;
	366
	367	list_for_each_entry(ram, &persistent_ram_list, node) {
	368	start = ram->start;
	369	for (i = 0; i < ram->num_descs; i++) {
	370	desc = &ram->descs[i];
	371	if (!strcmp(desc->name, name))
	372	return persistent_ram_buffer_map(start,
	373	desc->size, prz);
	374	start += desc->size;
	375	}
	376	}
	377
	378	return -EINVAL;
	379	}
	380
bb4206f2	381	static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
404a6043	382	{
bb4206f2	383	int ret;
c672528a	384
9cc05ad9	385	prz->ecc = ecc;
bb4206f2	386
404a6043	387	ret = persistent_ram_init_ecc(prz, prz->buffer_size);
9cc05ad9	388	if (ret)
bb4206f2	389	return ret;
c672528a	390
404a6043	391	if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
808d0387 CC	392	if (buffer_size(prz) > prz->buffer_size \|\|
	393	buffer_start(prz) > buffer_size(prz))
	394	pr_info("persistent_ram: found existing invalid buffer,"
f56d711b	395	" size %zu, start %zu\n",
808d0387	396	buffer_size(prz), buffer_start(prz));
c672528a	397	else {
808d0387	398	pr_info("persistent_ram: found existing buffer,"
f56d711b	399	" size %zu, start %zu\n",
808d0387	400	buffer_size(prz), buffer_start(prz));
c672528a CC	401	persistent_ram_save_old(prz);
	402	}
	403	} else {
808d0387 CC	404	pr_info("persistent_ram: no valid data in buffer"
808d0387 CC	405	" (sig = 0x%08x)\n", prz->buffer->sig);
c672528a CC	406	}
c672528a CC	407
404a6043	408	prz->buffer->sig = PERSISTENT_RAM_SIG;
808d0387 CC	409	atomic_set(&prz->buffer->start, 0);
808d0387 CC	410	atomic_set(&prz->buffer->size, 0);
c672528a	411
bb4206f2 AV	412	return 0;
	413	}
	414
	415	static __init
	416	struct persistent_ram_zone __persistent_ram_init(struct device dev, bool ecc)
	417	{
	418	struct persistent_ram_zone *prz;
	419	int ret = -ENOMEM;
	420
	421	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	422	if (!prz) {
	423	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	424	goto err;
	425	}
	426
	427	ret = persistent_ram_buffer_init(dev_name(dev), prz);
	428	if (ret) {
	429	pr_err("persistent_ram: failed to initialize buffer\n");
	430	goto err;
	431	}
	432
	433	persistent_ram_post_init(prz, ecc);
	434
404a6043	435	return prz;
474a8988 JJ	436	err:
	437	kfree(prz);
	438	return ERR_PTR(ret);
404a6043	439	}
c672528a	440
404a6043 CC	441	struct persistent_ram_zone * __init
	442	persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
	443	{
	444	return __persistent_ram_init(dev, ecc);
c672528a CC	445	}
c672528a CC	446
404a6043	447	int __init persistent_ram_early_init(struct persistent_ram *ram)
c672528a	448	{
404a6043 CC	449	int ret;
	450
	451	ret = memblock_reserve(ram->start, ram->size);
	452	if (ret) {
	453	pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
	454	(long)ram->start, (long)(ram->start + ram->size - 1));
	455	return ret;
	456	}
	457
	458	list_add_tail(&ram->node, &persistent_ram_list);
	459
	460	pr_info("Initialized persistent memory from %08lx-%08lx\n",
	461	(long)ram->start, (long)(ram->start + ram->size - 1));
	462
	463	return 0;
c672528a	464	}