[deliverable/linux.git] / fs / pstore / ram_core.c

/*
 * Copyright (C) 2012 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/list.h>
#include <linux/memblock.h>
#include <linux/rslib.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/pstore_ram.h>
#include <asm/page.h>

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

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

static __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);
}

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 __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);
			return 0;
		}
	} else {
		pr_info("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 (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
		vunmap(prz->vaddr);
	} else {
		iounmap(prz->vaddr);
		release_mem_region(prz->paddr, prz->size);
	}
	persistent_ram_free_old(prz);
	kfree(prz);
}

struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
						       size_t size,
						       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_map(start, size, prz);
	if (ret)
		goto err;

	persistent_ram_post_init(prz, ecc);

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

#ifndef MODULE
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;
	}

	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;
}
#endif
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
404a6043	38	static __initdata LIST_HEAD(persistent_ram_list);
c672528a	39
808d0387 CC	40	static inline size_t buffer_size(struct persistent_ram_zone *prz)
	41	{
	42	return atomic_read(&prz->buffer->size);
	43	}
	44
	45	static inline size_t buffer_start(struct persistent_ram_zone *prz)
	46	{
	47	return atomic_read(&prz->buffer->start);
	48	}
	49
	50	/* increase and wrap the start pointer, returning the old value */
	51	static inline size_t buffer_start_add(struct persistent_ram_zone *prz, size_t a)
	52	{
	53	int old;
	54	int new;
	55
	56	do {
	57	old = atomic_read(&prz->buffer->start);
	58	new = old + a;
	59	while (unlikely(new > prz->buffer_size))
	60	new -= prz->buffer_size;
	61	} while (atomic_cmpxchg(&prz->buffer->start, old, new) != old);
	62
	63	return old;
	64	}
	65
	66	/* increase the size counter until it hits the max size */
	67	static inline void buffer_size_add(struct persistent_ram_zone *prz, size_t a)
	68	{
	69	size_t old;
	70	size_t new;
	71
	72	if (atomic_read(&prz->buffer->size) == prz->buffer_size)
	73	return;
	74
	75	do {
	76	old = atomic_read(&prz->buffer->size);
	77	new = old + a;
	78	if (new > prz->buffer_size)
	79	new = prz->buffer_size;
	80	} while (atomic_cmpxchg(&prz->buffer->size, old, new) != old);
	81	}
	82
a15d0b36	83	static void notrace persistent_ram_encode_rs8(struct persistent_ram_zone *prz,
c672528a CC	84	uint8_t data, size_t len, uint8_t ecc)
	85	{
	86	int i;
9cc05ad9 CC	87	uint16_t par[prz->ecc_size];
9cc05ad9 CC	88
c672528a CC	89	/* Initialize the parity buffer */
	90	memset(par, 0, sizeof(par));
	91	encode_rs8(prz->rs_decoder, data, len, par, 0);
9cc05ad9	92	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	93	ecc[i] = par[i];
	94	}
	95
	96	static int persistent_ram_decode_rs8(struct persistent_ram_zone *prz,
	97	void data, size_t len, uint8_t ecc)
	98	{
	99	int i;
9cc05ad9 CC	100	uint16_t par[prz->ecc_size];
	101
	102	for (i = 0; i < prz->ecc_size; i++)
c672528a CC	103	par[i] = ecc[i];
	104	return decode_rs8(prz->rs_decoder, data, par, len,
	105	NULL, 0, NULL, 0, NULL);
	106	}
c672528a	107
a15d0b36	108	static void notrace persistent_ram_update_ecc(struct persistent_ram_zone *prz,
808d0387	109	unsigned int start, unsigned int count)
c672528a CC	110	{
c672528a CC	111	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	112	uint8_t *buffer_end = buffer->data + prz->buffer_size;
	113	uint8_t *block;
	114	uint8_t *par;
9cc05ad9 CC	115	int ecc_block_size = prz->ecc_block_size;
	116	int ecc_size = prz->ecc_size;
	117	int size = prz->ecc_block_size;
	118
	119	if (!prz->ecc)
	120	return;
	121
808d0387 CC	122	block = buffer->data + (start & ~(ecc_block_size - 1));
	123	par = prz->par_buffer + (start / ecc_block_size) * prz->ecc_size;
	124
c672528a	125	do {
9cc05ad9	126	if (block + ecc_block_size > buffer_end)
c672528a CC	127	size = buffer_end - block;
c672528a CC	128	persistent_ram_encode_rs8(prz, block, size, par);
9cc05ad9 CC	129	block += ecc_block_size;
9cc05ad9 CC	130	par += ecc_size;
808d0387	131	} while (block < buffer->data + start + count);
c672528a CC	132	}
c672528a CC	133
9cc05ad9	134	static void persistent_ram_update_header_ecc(struct persistent_ram_zone *prz)
c672528a	135	{
c672528a CC	136	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	137
9cc05ad9 CC	138	if (!prz->ecc)
	139	return;
	140
c672528a CC	141	persistent_ram_encode_rs8(prz, (uint8_t )buffer, sizeof(buffer),
c672528a CC	142	prz->par_header);
c672528a CC	143	}
c672528a CC	144
9cc05ad9	145	static void persistent_ram_ecc_old(struct persistent_ram_zone *prz)
c672528a CC	146	{
c672528a CC	147	struct persistent_ram_buffer *buffer = prz->buffer;
c672528a CC	148	uint8_t *block;
	149	uint8_t *par;
	150
9cc05ad9 CC	151	if (!prz->ecc)
	152	return;
	153
c672528a CC	154	block = buffer->data;
c672528a CC	155	par = prz->par_buffer;
808d0387	156	while (block < buffer->data + buffer_size(prz)) {
c672528a	157	int numerr;
9cc05ad9	158	int size = prz->ecc_block_size;
c672528a CC	159	if (block + size > buffer->data + prz->buffer_size)
	160	size = buffer->data + prz->buffer_size - block;
	161	numerr = persistent_ram_decode_rs8(prz, block, size, par);
	162	if (numerr > 0) {
9cc05ad9	163	pr_devel("persistent_ram: error in block %p, %d\n",
c672528a	164	block, numerr);
c672528a CC	165	prz->corrected_bytes += numerr;
c672528a CC	166	} else if (numerr < 0) {
9cc05ad9	167	pr_devel("persistent_ram: uncorrectable error in block %p\n",
c672528a	168	block);
c672528a CC	169	prz->bad_blocks++;
c672528a CC	170	}
9cc05ad9 CC	171	block += prz->ecc_block_size;
	172	par += prz->ecc_size;
	173	}
	174	}
	175
	176	static int persistent_ram_init_ecc(struct persistent_ram_zone *prz,
	177	size_t buffer_size)
	178	{
	179	int numerr;
	180	struct persistent_ram_buffer *buffer = prz->buffer;
	181	int ecc_blocks;
	182
	183	if (!prz->ecc)
	184	return 0;
	185
	186	prz->ecc_block_size = 128;
	187	prz->ecc_size = 16;
	188	prz->ecc_symsize = 8;
	189	prz->ecc_poly = 0x11d;
	190
	191	ecc_blocks = DIV_ROUND_UP(prz->buffer_size, prz->ecc_block_size);
	192	prz->buffer_size -= (ecc_blocks + 1) * prz->ecc_size;
	193
	194	if (prz->buffer_size > buffer_size) {
	195	pr_err("persistent_ram: invalid size %zu, non-ecc datasize %zu\n",
	196	buffer_size, prz->buffer_size);
	197	return -EINVAL;
	198	}
	199
	200	prz->par_buffer = buffer->data + prz->buffer_size;
	201	prz->par_header = prz->par_buffer + ecc_blocks * prz->ecc_size;
	202
	203	/*
	204	* first consecutive root is 0
	205	* primitive element to generate roots = 1
	206	*/
	207	prz->rs_decoder = init_rs(prz->ecc_symsize, prz->ecc_poly, 0, 1,
	208	prz->ecc_size);
	209	if (prz->rs_decoder == NULL) {
	210	pr_info("persistent_ram: init_rs failed\n");
	211	return -EINVAL;
c672528a	212	}
9cc05ad9 CC	213
	214	prz->corrected_bytes = 0;
	215	prz->bad_blocks = 0;
	216
	217	numerr = persistent_ram_decode_rs8(prz, buffer, sizeof(*buffer),
	218	prz->par_header);
	219	if (numerr > 0) {
	220	pr_info("persistent_ram: error in header, %d\n", numerr);
	221	prz->corrected_bytes += numerr;
	222	} else if (numerr < 0) {
	223	pr_info("persistent_ram: uncorrectable error in header\n");
	224	prz->bad_blocks++;
	225	}
	226
	227	return 0;
	228	}
	229
	230	ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz,
	231	char *str, size_t len)
	232	{
	233	ssize_t ret;
	234
	235	if (prz->corrected_bytes \|\| prz->bad_blocks)
	236	ret = snprintf(str, len, ""
	237	"\n%d Corrected bytes, %d unrecoverable blocks\n",
	238	prz->corrected_bytes, prz->bad_blocks);
	239	else
	240	ret = snprintf(str, len, "\nNo errors detected\n");
	241
	242	return ret;
	243	}
	244
a15d0b36	245	static void notrace persistent_ram_update(struct persistent_ram_zone *prz,
808d0387	246	const void *s, unsigned int start, unsigned int count)
9cc05ad9 CC	247	{
9cc05ad9 CC	248	struct persistent_ram_buffer *buffer = prz->buffer;
808d0387 CC	249	memcpy(buffer->data + start, s, count);
808d0387 CC	250	persistent_ram_update_ecc(prz, start, count);
9cc05ad9 CC	251	}
9cc05ad9 CC	252
201e4aca	253	void persistent_ram_save_old(struct persistent_ram_zone *prz)
9cc05ad9 CC	254	{
9cc05ad9 CC	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	258
201e4aca AV	259	if (!size)
201e4aca AV	260	return;
c672528a	261
201e4aca AV	262	if (!prz->old_log) {
	263	persistent_ram_ecc_old(prz);
	264	prz->old_log = kmalloc(size, GFP_KERNEL);
	265	}
	266	if (!prz->old_log) {
c672528a CC	267	pr_err("persistent_ram: failed to allocate buffer\n");
	268	return;
	269	}
	270
808d0387 CC	271	prz->old_log_size = size;
	272	memcpy(prz->old_log, &buffer->data[start], size - start);
	273	memcpy(prz->old_log + size - start, &buffer->data[0], start);
c672528a CC	274	}
c672528a CC	275
a15d0b36	276	int notrace persistent_ram_write(struct persistent_ram_zone *prz,
c672528a CC	277	const void *s, unsigned int count)
	278	{
	279	int rem;
	280	int c = count;
808d0387	281	size_t start;
c672528a	282
808d0387	283	if (unlikely(c > prz->buffer_size)) {
c672528a CC	284	s += c - prz->buffer_size;
	285	c = prz->buffer_size;
	286	}
808d0387	287
484dd30e	288	buffer_size_add(prz, c);
808d0387 CC	289
	290	start = buffer_start_add(prz, c);
	291
	292	rem = prz->buffer_size - start;
	293	if (unlikely(rem < c)) {
	294	persistent_ram_update(prz, s, start, rem);
c672528a CC	295	s += rem;
c672528a CC	296	c -= rem;
808d0387	297	start = 0;
c672528a	298	}
808d0387	299	persistent_ram_update(prz, s, start, c);
c672528a	300
9cc05ad9	301	persistent_ram_update_header_ecc(prz);
c672528a CC	302
	303	return count;
	304	}
	305
c672528a CC	306	size_t persistent_ram_old_size(struct persistent_ram_zone *prz)
	307	{
	308	return prz->old_log_size;
	309	}
	310
	311	void persistent_ram_old(struct persistent_ram_zone prz)
	312	{
	313	return prz->old_log;
	314	}
	315
	316	void persistent_ram_free_old(struct persistent_ram_zone *prz)
	317	{
	318	kfree(prz->old_log);
	319	prz->old_log = NULL;
	320	prz->old_log_size = 0;
	321	}
	322
fce39793 AV	323	void persistent_ram_zap(struct persistent_ram_zone *prz)
	324	{
	325	atomic_set(&prz->buffer->start, 0);
	326	atomic_set(&prz->buffer->size, 0);
	327	persistent_ram_update_header_ecc(prz);
	328	}
	329
2b1321e4	330	static void *persistent_ram_vmap(phys_addr_t start, size_t size)
c672528a	331	{
404a6043 CC	332	struct page **pages;
	333	phys_addr_t page_start;
	334	unsigned int page_count;
	335	pgprot_t prot;
	336	unsigned int i;
2b1321e4	337	void *vaddr;
404a6043 CC	338
	339	page_start = start - offset_in_page(start);
	340	page_count = DIV_ROUND_UP(size + offset_in_page(start), PAGE_SIZE);
	341
	342	prot = pgprot_noncached(PAGE_KERNEL);
	343
	344	pages = kmalloc(sizeof(struct page ) page_count, GFP_KERNEL);
	345	if (!pages) {
	346	pr_err("%s: Failed to allocate array for %u pages\n", __func__,
	347	page_count);
2b1321e4	348	return NULL;
404a6043 CC	349	}
	350
	351	for (i = 0; i < page_count; i++) {
	352	phys_addr_t addr = page_start + i * PAGE_SIZE;
	353	pages[i] = pfn_to_page(addr >> PAGE_SHIFT);
	354	}
2b1321e4	355	vaddr = vmap(pages, page_count, VM_MAP, prot);
404a6043	356	kfree(pages);
2b1321e4 AV	357
	358	return vaddr;
	359	}
	360
24c3d2f3 AV	361	static void *persistent_ram_iomap(phys_addr_t start, size_t size)
	362	{
	363	if (!request_mem_region(start, size, "persistent_ram")) {
	364	pr_err("request mem region (0x%llx@0x%llx) failed\n",
	365	(unsigned long long)size, (unsigned long long)start);
	366	return NULL;
	367	}
	368
	369	return ioremap(start, size);
	370	}
	371
2b1321e4 AV	372	static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size,
	373	struct persistent_ram_zone *prz)
	374	{
d3b48769 AV	375	prz->paddr = start;
	376	prz->size = size;
	377
24c3d2f3 AV	378	if (pfn_valid(start >> PAGE_SHIFT))
	379	prz->vaddr = persistent_ram_vmap(start, size);
	380	else
	381	prz->vaddr = persistent_ram_iomap(start, size);
	382
404a6043	383	if (!prz->vaddr) {
2b1321e4 AV	384	pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__,
2b1321e4 AV	385	(unsigned long long)size, (unsigned long long)start);
404a6043 CC	386	return -ENOMEM;
	387	}
	388
	389	prz->buffer = prz->vaddr + offset_in_page(start);
	390	prz->buffer_size = size - sizeof(struct persistent_ram_buffer);
	391
	392	return 0;
	393	}
	394
bb4206f2	395	static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool ecc)
404a6043	396	{
bb4206f2	397	int ret;
c672528a	398
9cc05ad9	399	prz->ecc = ecc;
bb4206f2	400
404a6043	401	ret = persistent_ram_init_ecc(prz, prz->buffer_size);
9cc05ad9	402	if (ret)
bb4206f2	403	return ret;
c672528a	404
404a6043	405	if (prz->buffer->sig == PERSISTENT_RAM_SIG) {
808d0387 CC	406	if (buffer_size(prz) > prz->buffer_size \|\|
	407	buffer_start(prz) > buffer_size(prz))
	408	pr_info("persistent_ram: found existing invalid buffer,"
f56d711b	409	" size %zu, start %zu\n",
808d0387	410	buffer_size(prz), buffer_start(prz));
c672528a	411	else {
808d0387	412	pr_info("persistent_ram: found existing buffer,"
f56d711b	413	" size %zu, start %zu\n",
808d0387	414	buffer_size(prz), buffer_start(prz));
c672528a	415	persistent_ram_save_old(prz);
25b63da6	416	return 0;
c672528a CC	417	}
c672528a CC	418	} else {
808d0387 CC	419	pr_info("persistent_ram: no valid data in buffer"
808d0387 CC	420	" (sig = 0x%08x)\n", prz->buffer->sig);
c672528a CC	421	}
c672528a CC	422
404a6043	423	prz->buffer->sig = PERSISTENT_RAM_SIG;
fce39793	424	persistent_ram_zap(prz);
c672528a	425
bb4206f2 AV	426	return 0;
	427	}
	428
d3b48769 AV	429	void persistent_ram_free(struct persistent_ram_zone *prz)
	430	{
	431	if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
	432	vunmap(prz->vaddr);
	433	} else {
	434	iounmap(prz->vaddr);
	435	release_mem_region(prz->paddr, prz->size);
	436	}
	437	persistent_ram_free_old(prz);
	438	kfree(prz);
	439	}
	440
8cf5aff8 AV	441	struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,
	442	size_t size,
	443	bool ecc)
	444	{
	445	struct persistent_ram_zone *prz;
	446	int ret = -ENOMEM;
	447
	448	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	449	if (!prz) {
	450	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	451	goto err;
	452	}
	453
	454	ret = persistent_ram_buffer_map(start, size, prz);
	455	if (ret)
	456	goto err;
	457
	458	persistent_ram_post_init(prz, ecc);
8cf5aff8 AV	459
	460	return prz;
	461	err:
	462	kfree(prz);
	463	return ERR_PTR(ret);
	464	}
	465
7dd8e9be AV	466	#ifndef MODULE
	467	static int __init persistent_ram_buffer_init(const char *name,
	468	struct persistent_ram_zone *prz)
	469	{
	470	int i;
	471	struct persistent_ram *ram;
	472	struct persistent_ram_descriptor *desc;
	473	phys_addr_t start;
	474
	475	list_for_each_entry(ram, &persistent_ram_list, node) {
	476	start = ram->start;
	477	for (i = 0; i < ram->num_descs; i++) {
	478	desc = &ram->descs[i];
	479	if (!strcmp(desc->name, name))
	480	return persistent_ram_buffer_map(start,
	481	desc->size, prz);
	482	start += desc->size;
	483	}
	484	}
	485
	486	return -EINVAL;
	487	}
	488
bb4206f2 AV	489	static __init
	490	struct persistent_ram_zone __persistent_ram_init(struct device dev, bool ecc)
	491	{
	492	struct persistent_ram_zone *prz;
	493	int ret = -ENOMEM;
	494
	495	prz = kzalloc(sizeof(struct persistent_ram_zone), GFP_KERNEL);
	496	if (!prz) {
	497	pr_err("persistent_ram: failed to allocate persistent ram zone\n");
	498	goto err;
	499	}
	500
	501	ret = persistent_ram_buffer_init(dev_name(dev), prz);
	502	if (ret) {
	503	pr_err("persistent_ram: failed to initialize buffer\n");
	504	goto err;
	505	}
	506
	507	persistent_ram_post_init(prz, ecc);
	508
404a6043	509	return prz;
474a8988 JJ	510	err:
	511	kfree(prz);
	512	return ERR_PTR(ret);
404a6043	513	}
c672528a	514
404a6043 CC	515	struct persistent_ram_zone * __init
	516	persistent_ram_init_ringbuffer(struct device *dev, bool ecc)
	517	{
	518	return __persistent_ram_init(dev, ecc);
c672528a CC	519	}
c672528a CC	520
404a6043	521	int __init persistent_ram_early_init(struct persistent_ram *ram)
c672528a	522	{
404a6043 CC	523	int ret;
	524
	525	ret = memblock_reserve(ram->start, ram->size);
	526	if (ret) {
	527	pr_err("Failed to reserve persistent memory from %08lx-%08lx\n",
	528	(long)ram->start, (long)(ram->start + ram->size - 1));
	529	return ret;
	530	}
	531
	532	list_add_tail(&ram->node, &persistent_ram_list);
	533
	534	pr_info("Initialized persistent memory from %08lx-%08lx\n",
	535	(long)ram->start, (long)(ram->start + ram->size - 1));
	536
	537	return 0;
c672528a	538	}
7dd8e9be	539	#endif