| /* |
| * 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/persistent_ram.h> |
| #include <linux/rslib.h> |
| #include <linux/slab.h> |
| #include <linux/vmalloc.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 __devinitdata 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, struct persistent_ram *ram) |
| { |
| int numerr; |
| struct persistent_ram_buffer *buffer = prz->buffer; |
| int ecc_blocks; |
| |
| if (!prz->ecc) |
| return 0; |
| |
| prz->ecc_block_size = ram->ecc_block_size ?: 128; |
| prz->ecc_size = ram->ecc_size ?: 16; |
| prz->ecc_symsize = ram->ecc_symsize ?: 8; |
| prz->ecc_poly = ram->ecc_poly ?: 0x11d; |
| |
| ecc_blocks = DIV_ROUND_UP(prz->buffer_size - prz->ecc_size, |
| prz->ecc_block_size + prz->ecc_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 __devinit |
| 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 __devinit persistent_ram_buffer_init(const char *name, |
| struct persistent_ram_zone *prz, struct persistent_ram **ramp) |
| { |
| 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)) { |
| *ramp = ram; |
| return persistent_ram_buffer_map(start, |
| desc->size, prz); |
| } |
| start += desc->size; |
| } |
| } |
| |
| return -EINVAL; |
| } |
| |
| static __devinit |
| struct persistent_ram_zone *__persistent_ram_init(struct device *dev, bool ecc) |
| { |
| struct persistent_ram *ram; |
| 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; |
| } |
| |
| INIT_LIST_HEAD(&prz->node); |
| |
| ret = persistent_ram_buffer_init(dev_name(dev), prz, &ram); |
| 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, ram); |
| 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 * __devinit |
| 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; |
| } |