/* * nvmem framework core. * * Copyright (C) 2015 Srinivas Kandagatla * Copyright (C) 2013 Maxime Ripard * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and * only version 2 as published by the Free Software Foundation. * * 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 #include #include #include #include #include #include #include #include #include struct nvmem_device { const char *name; struct module *owner; struct device dev; int stride; int word_size; int ncells; int id; int users; size_t size; bool read_only; int flags; struct bin_attribute eeprom; struct device *base_dev; nvmem_reg_read_t reg_read; nvmem_reg_write_t reg_write; void *priv; }; #define FLAG_COMPAT BIT(0) struct nvmem_cell { const char *name; int offset; int bytes; int bit_offset; int nbits; struct nvmem_device *nvmem; struct list_head node; }; static DEFINE_MUTEX(nvmem_mutex); static DEFINE_IDA(nvmem_ida); static LIST_HEAD(nvmem_cells); static DEFINE_MUTEX(nvmem_cells_mutex); #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key eeprom_lock_key; #endif #define to_nvmem_device(d) container_of(d, struct nvmem_device, dev) static int nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, void *val, size_t bytes) { if (nvmem->reg_read) return nvmem->reg_read(nvmem->priv, offset, val, bytes); return -EINVAL; } static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, void *val, size_t bytes) { if (nvmem->reg_write) return nvmem->reg_write(nvmem->priv, offset, val, bytes); return -EINVAL; } static ssize_t bin_attr_nvmem_read(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t pos, size_t count) { struct device *dev; struct nvmem_device *nvmem; int rc; if (attr->private) dev = attr->private; else dev = container_of(kobj, struct device, kobj); nvmem = to_nvmem_device(dev); /* Stop the user from reading */ if (pos >= nvmem->size) return 0; if (count < nvmem->word_size) return -EINVAL; if (pos + count > nvmem->size) count = nvmem->size - pos; count = round_down(count, nvmem->word_size); rc = nvmem_reg_read(nvmem, pos, buf, count); if (rc) return rc; return count; } static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj, struct bin_attribute *attr, char *buf, loff_t pos, size_t count) { struct device *dev; struct nvmem_device *nvmem; int rc; if (attr->private) dev = attr->private; else dev = container_of(kobj, struct device, kobj); nvmem = to_nvmem_device(dev); /* Stop the user from writing */ if (pos >= nvmem->size) return 0; if (count < nvmem->word_size) return -EINVAL; if (pos + count > nvmem->size) count = nvmem->size - pos; count = round_down(count, nvmem->word_size); rc = nvmem_reg_write(nvmem, pos, buf, count); if (rc) return rc; return count; } /* default read/write permissions */ static struct bin_attribute bin_attr_rw_nvmem = { .attr = { .name = "nvmem", .mode = S_IWUSR | S_IRUGO, }, .read = bin_attr_nvmem_read, .write = bin_attr_nvmem_write, }; static struct bin_attribute *nvmem_bin_rw_attributes[] = { &bin_attr_rw_nvmem, NULL, }; static const struct attribute_group nvmem_bin_rw_group = { .bin_attrs = nvmem_bin_rw_attributes, }; static const struct attribute_group *nvmem_rw_dev_groups[] = { &nvmem_bin_rw_group, NULL, }; /* read only permission */ static struct bin_attribute bin_attr_ro_nvmem = { .attr = { .name = "nvmem", .mode = S_IRUGO, }, .read = bin_attr_nvmem_read, }; static struct bin_attribute *nvmem_bin_ro_attributes[] = { &bin_attr_ro_nvmem, NULL, }; static const struct attribute_group nvmem_bin_ro_group = { .bin_attrs = nvmem_bin_ro_attributes, }; static const struct attribute_group *nvmem_ro_dev_groups[] = { &nvmem_bin_ro_group, NULL, }; /* default read/write permissions, root only */ static struct bin_attribute bin_attr_rw_root_nvmem = { .attr = { .name = "nvmem", .mode = S_IWUSR | S_IRUSR, }, .read = bin_attr_nvmem_read, .write = bin_attr_nvmem_write, }; static struct bin_attribute *nvmem_bin_rw_root_attributes[] = { &bin_attr_rw_root_nvmem, NULL, }; static const struct attribute_group nvmem_bin_rw_root_group = { .bin_attrs = nvmem_bin_rw_root_attributes, }; static const struct attribute_group *nvmem_rw_root_dev_groups[] = { &nvmem_bin_rw_root_group, NULL, }; /* read only permission, root only */ static struct bin_attribute bin_attr_ro_root_nvmem = { .attr = { .name = "nvmem", .mode = S_IRUSR, }, .read = bin_attr_nvmem_read, }; static struct bin_attribute *nvmem_bin_ro_root_attributes[] = { &bin_attr_ro_root_nvmem, NULL, }; static const struct attribute_group nvmem_bin_ro_root_group = { .bin_attrs = nvmem_bin_ro_root_attributes, }; static const struct attribute_group *nvmem_ro_root_dev_groups[] = { &nvmem_bin_ro_root_group, NULL, }; static void nvmem_release(struct device *dev) { struct nvmem_device *nvmem = to_nvmem_device(dev); ida_simple_remove(&nvmem_ida, nvmem->id); kfree(nvmem); } static const struct device_type nvmem_provider_type = { .release = nvmem_release, }; static struct bus_type nvmem_bus_type = { .name = "nvmem", }; static int of_nvmem_match(struct device *dev, void *nvmem_np) { return dev->of_node == nvmem_np; } static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np) { struct device *d; if (!nvmem_np) return NULL; d = bus_find_device(&nvmem_bus_type, NULL, nvmem_np, of_nvmem_match); if (!d) return NULL; return to_nvmem_device(d); } static struct nvmem_cell *nvmem_find_cell(const char *cell_id) { struct nvmem_cell *p; mutex_lock(&nvmem_cells_mutex); list_for_each_entry(p, &nvmem_cells, node) if (p && !strcmp(p->name, cell_id)) { mutex_unlock(&nvmem_cells_mutex); return p; } mutex_unlock(&nvmem_cells_mutex); return NULL; } static void nvmem_cell_drop(struct nvmem_cell *cell) { mutex_lock(&nvmem_cells_mutex); list_del(&cell->node); mutex_unlock(&nvmem_cells_mutex); kfree(cell); } static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem) { struct nvmem_cell *cell; struct list_head *p, *n; list_for_each_safe(p, n, &nvmem_cells) { cell = list_entry(p, struct nvmem_cell, node); if (cell->nvmem == nvmem) nvmem_cell_drop(cell); } } static void nvmem_cell_add(struct nvmem_cell *cell) { mutex_lock(&nvmem_cells_mutex); list_add_tail(&cell->node, &nvmem_cells); mutex_unlock(&nvmem_cells_mutex); } static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem, const struct nvmem_cell_info *info, struct nvmem_cell *cell) { cell->nvmem = nvmem; cell->offset = info->offset; cell->bytes = info->bytes; cell->name = info->name; cell->bit_offset = info->bit_offset; cell->nbits = info->nbits; if (cell->nbits) cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset, BITS_PER_BYTE); if (!IS_ALIGNED(cell->offset, nvmem->stride)) { dev_err(&nvmem->dev, "cell %s unaligned to nvmem stride %d\n", cell->name, nvmem->stride); return -EINVAL; } return 0; } static int nvmem_add_cells(struct nvmem_device *nvmem, const struct nvmem_config *cfg) { struct nvmem_cell **cells; const struct nvmem_cell_info *info = cfg->cells; int i, rval; cells = kcalloc(cfg->ncells, sizeof(*cells), GFP_KERNEL); if (!cells) return -ENOMEM; for (i = 0; i < cfg->ncells; i++) { cells[i] = kzalloc(sizeof(**cells), GFP_KERNEL); if (!cells[i]) { rval = -ENOMEM; goto err; } rval = nvmem_cell_info_to_nvmem_cell(nvmem, &info[i], cells[i]); if (rval) { kfree(cells[i]); goto err; } nvmem_cell_add(cells[i]); } nvmem->ncells = cfg->ncells; /* remove tmp array */ kfree(cells); return 0; err: while (i--) nvmem_cell_drop(cells[i]); kfree(cells); return rval; } /* * nvmem_setup_compat() - Create an additional binary entry in * drivers sys directory, to be backwards compatible with the older * drivers/misc/eeprom drivers. */ static int nvmem_setup_compat(struct nvmem_device *nvmem, const struct nvmem_config *config) { int rval; if (!config->base_dev) return -EINVAL; if (nvmem->read_only) nvmem->eeprom = bin_attr_ro_root_nvmem; else nvmem->eeprom = bin_attr_rw_root_nvmem; nvmem->eeprom.attr.name = "eeprom"; nvmem->eeprom.size = nvmem->size; #ifdef CONFIG_DEBUG_LOCK_ALLOC nvmem->eeprom.attr.key = &eeprom_lock_key; #endif nvmem->eeprom.private = &nvmem->dev; nvmem->base_dev = config->base_dev; rval = device_create_bin_file(nvmem->base_dev, &nvmem->eeprom); if (rval) { dev_err(&nvmem->dev, "Failed to create eeprom binary file %d\n", rval); return rval; } nvmem->flags |= FLAG_COMPAT; return 0; } /** * nvmem_register() - Register a nvmem device for given nvmem_config. * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem * * @config: nvmem device configuration with which nvmem device is created. * * Return: Will be an ERR_PTR() on error or a valid pointer to nvmem_device * on success. */ struct nvmem_device *nvmem_register(const struct nvmem_config *config) { struct nvmem_device *nvmem; struct device_node *np; int rval; if (!config->dev) return ERR_PTR(-EINVAL); nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL); if (!nvmem) return ERR_PTR(-ENOMEM); rval = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL); if (rval < 0) { kfree(nvmem); return ERR_PTR(rval); } nvmem->id = rval; nvmem->owner = config->owner; nvmem->stride = config->stride; nvmem->word_size = config->word_size; nvmem->size = config->size; nvmem->dev.type = &nvmem_provider_type; nvmem->dev.bus = &nvmem_bus_type; nvmem->dev.parent = config->dev; nvmem->priv = config->priv; nvmem->reg_read = config->reg_read; nvmem->reg_write = config->reg_write; np = config->dev->of_node; nvmem->dev.of_node = np; dev_set_name(&nvmem->dev, "%s%d", config->name ? : "nvmem", config->name ? config->id : nvmem->id); nvmem->read_only = of_property_read_bool(np, "read-only") | config->read_only; if (config->root_only) nvmem->dev.groups = nvmem->read_only ? nvmem_ro_root_dev_groups : nvmem_rw_root_dev_groups; else nvmem->dev.groups = nvmem->read_only ? nvmem_ro_dev_groups : nvmem_rw_dev_groups; device_initialize(&nvmem->dev); dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name); rval = device_add(&nvmem->dev); if (rval) goto err_put_device; if (config->compat) { rval = nvmem_setup_compat(nvmem, config); if (rval) goto err_device_del; } if (config->cells) nvmem_add_cells(nvmem, config); return nvmem; err_device_del: device_del(&nvmem->dev); err_put_device: put_device(&nvmem->dev); return ERR_PTR(rval); } EXPORT_SYMBOL_GPL(nvmem_register); /** * nvmem_unregister() - Unregister previously registered nvmem device * * @nvmem: Pointer to previously registered nvmem device. * * Return: Will be an negative on error or a zero on success. */ int nvmem_unregister(struct nvmem_device *nvmem) { mutex_lock(&nvmem_mutex); if (nvmem->users) { mutex_unlock(&nvmem_mutex); return -EBUSY; } mutex_unlock(&nvmem_mutex); if (nvmem->flags & FLAG_COMPAT) device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); nvmem_device_remove_all_cells(nvmem); device_del(&nvmem->dev); put_device(&nvmem->dev); return 0; } EXPORT_SYMBOL_GPL(nvmem_unregister); static struct nvmem_device *__nvmem_device_get(struct device_node *np, struct nvmem_cell **cellp, const char *cell_id) { struct nvmem_device *nvmem = NULL; mutex_lock(&nvmem_mutex); if (np) { nvmem = of_nvmem_find(np); if (!nvmem) { mutex_unlock(&nvmem_mutex); return ERR_PTR(-EPROBE_DEFER); } } else { struct nvmem_cell *cell = nvmem_find_cell(cell_id); if (cell) { nvmem = cell->nvmem; *cellp = cell; } if (!nvmem) { mutex_unlock(&nvmem_mutex); return ERR_PTR(-ENOENT); } } nvmem->users++; mutex_unlock(&nvmem_mutex); if (!try_module_get(nvmem->owner)) { dev_err(&nvmem->dev, "could not increase module refcount for cell %s\n", nvmem->name); mutex_lock(&nvmem_mutex); nvmem->users--; mutex_unlock(&nvmem_mutex); return ERR_PTR(-EINVAL); } return nvmem; } static void __nvmem_device_put(struct nvmem_device *nvmem) { module_put(nvmem->owner); mutex_lock(&nvmem_mutex); nvmem->users--; mutex_unlock(&nvmem_mutex); } static int nvmem_match(struct device *dev, void *data) { return !strcmp(dev_name(dev), data); } static struct nvmem_device *nvmem_find(const char *name) { struct device *d; d = bus_find_device(&nvmem_bus_type, NULL, (void *)name, nvmem_match); if (!d) return NULL; return to_nvmem_device(d); } #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF) /** * of_nvmem_device_get() - Get nvmem device from a given id * * @np: Device tree node that uses the nvmem device. * @id: nvmem name from nvmem-names property. * * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device * on success. */ struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id) { struct device_node *nvmem_np; int index; index = of_property_match_string(np, "nvmem-names", id); nvmem_np = of_parse_phandle(np, "nvmem", index); if (!nvmem_np) return ERR_PTR(-EINVAL); return __nvmem_device_get(nvmem_np, NULL, NULL); } EXPORT_SYMBOL_GPL(of_nvmem_device_get); #endif /** * nvmem_device_get() - Get nvmem device from a given id * * @dev: Device that uses the nvmem device. * @dev_name: name of the requested nvmem device. * * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device * on success. */ struct nvmem_device *nvmem_device_get(struct device *dev, const char *dev_name) { if (dev->of_node) { /* try dt first */ struct nvmem_device *nvmem; nvmem = of_nvmem_device_get(dev->of_node, dev_name); if (!IS_ERR(nvmem) || PTR_ERR(nvmem) == -EPROBE_DEFER) return nvmem; } return nvmem_find(dev_name); } EXPORT_SYMBOL_GPL(nvmem_device_get); static int devm_nvmem_device_match(struct device *dev, void *res, void *data) { struct nvmem_device **nvmem = res; if (WARN_ON(!nvmem || !*nvmem)) return 0; return *nvmem == data; } static void devm_nvmem_device_release(struct device *dev, void *res) { nvmem_device_put(*(struct nvmem_device **)res); } /** * devm_nvmem_device_put() - put alredy got nvmem device * * @dev: Device that uses the nvmem device. * @nvmem: pointer to nvmem device allocated by devm_nvmem_cell_get(), * that needs to be released. */ void devm_nvmem_device_put(struct device *dev, struct nvmem_device *nvmem) { int ret; ret = devres_release(dev, devm_nvmem_device_release, devm_nvmem_device_match, nvmem); WARN_ON(ret); } EXPORT_SYMBOL_GPL(devm_nvmem_device_put); /** * nvmem_device_put() - put alredy got nvmem device * * @nvmem: pointer to nvmem device that needs to be released. */ void nvmem_device_put(struct nvmem_device *nvmem) { __nvmem_device_put(nvmem); } EXPORT_SYMBOL_GPL(nvmem_device_put); /** * devm_nvmem_device_get() - Get nvmem cell of device form a given id * * @dev: Device that requests the nvmem device. * @id: name id for the requested nvmem device. * * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_cell * on success. The nvmem_cell will be freed by the automatically once the * device is freed. */ struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id) { struct nvmem_device **ptr, *nvmem; ptr = devres_alloc(devm_nvmem_device_release, sizeof(*ptr), GFP_KERNEL); if (!ptr) return ERR_PTR(-ENOMEM); nvmem = nvmem_device_get(dev, id); if (!IS_ERR(nvmem)) { *ptr = nvmem; devres_add(dev, ptr); } else { devres_free(ptr); } return nvmem; } EXPORT_SYMBOL_GPL(devm_nvmem_device_get); static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id) { struct nvmem_cell *cell = NULL; struct nvmem_device *nvmem; nvmem = __nvmem_device_get(NULL, &cell, cell_id); if (IS_ERR(nvmem)) return ERR_CAST(nvmem); return cell; } #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF) /** * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id * * @np: Device tree node that uses the nvmem cell. * @name: nvmem cell name from nvmem-cell-names property, or NULL * for the cell at index 0 (the lone cell with no accompanying * nvmem-cell-names property). * * Return: Will be an ERR_PTR() on error or a valid pointer * to a struct nvmem_cell. The nvmem_cell will be freed by the * nvmem_cell_put(). */ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *name) { struct device_node *cell_np, *nvmem_np; struct nvmem_cell *cell; struct nvmem_device *nvmem; const __be32 *addr; int rval, len; int index = 0; /* if cell name exists, find index to the name */ if (name) index = of_property_match_string(np, "nvmem-cell-names", name); cell_np = of_parse_phandle(np, "nvmem-cells", index); if (!cell_np) return ERR_PTR(-EINVAL); nvmem_np = of_get_next_parent(cell_np); if (!nvmem_np) return ERR_PTR(-EINVAL); nvmem = __nvmem_device_get(nvmem_np, NULL, NULL); if (IS_ERR(nvmem)) return ERR_CAST(nvmem); addr = of_get_property(cell_np, "reg", &len); if (!addr || (len < 2 * sizeof(u32))) { dev_err(&nvmem->dev, "nvmem: invalid reg on %pOF\n", cell_np); rval = -EINVAL; goto err_mem; } cell = kzalloc(sizeof(*cell), GFP_KERNEL); if (!cell) { rval = -ENOMEM; goto err_mem; } cell->nvmem = nvmem; cell->offset = be32_to_cpup(addr++); cell->bytes = be32_to_cpup(addr); cell->name = cell_np->name; addr = of_get_property(cell_np, "bits", &len); if (addr && len == (2 * sizeof(u32))) { cell->bit_offset = be32_to_cpup(addr++); cell->nbits = be32_to_cpup(addr); } if (cell->nbits) cell->bytes = DIV_ROUND_UP(cell->nbits + cell->bit_offset, BITS_PER_BYTE); if (!IS_ALIGNED(cell->offset, nvmem->stride)) { dev_err(&nvmem->dev, "cell %s unaligned to nvmem stride %d\n", cell->name, nvmem->stride); rval = -EINVAL; goto err_sanity; } nvmem_cell_add(cell); return cell; err_sanity: kfree(cell); err_mem: __nvmem_device_put(nvmem); return ERR_PTR(rval); } EXPORT_SYMBOL_GPL(of_nvmem_cell_get); #endif /** * nvmem_cell_get() - Get nvmem cell of device form a given cell name * * @dev: Device that requests the nvmem cell. * @cell_id: nvmem cell name to get. * * Return: Will be an ERR_PTR() on error or a valid pointer * to a struct nvmem_cell. The nvmem_cell will be freed by the * nvmem_cell_put(). */ struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id) { struct nvmem_cell *cell; if (dev->of_node) { /* try dt first */ cell = of_nvmem_cell_get(dev->of_node, cell_id); if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER) return cell; } return nvmem_cell_get_from_list(cell_id); } EXPORT_SYMBOL_GPL(nvmem_cell_get); static void devm_nvmem_cell_release(struct device *dev, void *res) { nvmem_cell_put(*(struct nvmem_cell **)res); } /** * devm_nvmem_cell_get() - Get nvmem cell of device form a given id * * @dev: Device that requests the nvmem cell. * @id: nvmem cell name id to get. * * Return: Will be an ERR_PTR() on error or a valid pointer * to a struct nvmem_cell. The nvmem_cell will be freed by the * automatically once the device is freed. */ struct nvmem_cell *devm_nvmem_cell_get(struct device *dev, const char *id) { struct nvmem_cell **ptr, *cell; ptr = devres_alloc(devm_nvmem_cell_release, sizeof(*ptr), GFP_KERNEL); if (!ptr) return ERR_PTR(-ENOMEM); cell = nvmem_cell_get(dev, id); if (!IS_ERR(cell)) { *ptr = cell; devres_add(dev, ptr); } else { devres_free(ptr); } return cell; } EXPORT_SYMBOL_GPL(devm_nvmem_cell_get); static int devm_nvmem_cell_match(struct device *dev, void *res, void *data) { struct nvmem_cell **c = res; if (WARN_ON(!c || !*c)) return 0; return *c == data; } /** * devm_nvmem_cell_put() - Release previously allocated nvmem cell * from devm_nvmem_cell_get. * * @dev: Device that requests the nvmem cell. * @cell: Previously allocated nvmem cell by devm_nvmem_cell_get(). */ void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell) { int ret; ret = devres_release(dev, devm_nvmem_cell_release, devm_nvmem_cell_match, cell); WARN_ON(ret); } EXPORT_SYMBOL(devm_nvmem_cell_put); /** * nvmem_cell_put() - Release previously allocated nvmem cell. * * @cell: Previously allocated nvmem cell by nvmem_cell_get(). */ void nvmem_cell_put(struct nvmem_cell *cell) { struct nvmem_device *nvmem = cell->nvmem; __nvmem_device_put(nvmem); nvmem_cell_drop(cell); } EXPORT_SYMBOL_GPL(nvmem_cell_put); static inline void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf) { u8 *p, *b; int i, bit_offset = cell->bit_offset; p = b = buf; if (bit_offset) { /* First shift */ *b++ >>= bit_offset; /* setup rest of the bytes if any */ for (i = 1; i < cell->bytes; i++) { /* Get bits from next byte and shift them towards msb */ *p |= *b << (BITS_PER_BYTE - bit_offset); p = b; *b++ >>= bit_offset; } /* result fits in less bytes */ if (cell->bytes != DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE)) *p-- = 0; } /* clear msb bits if any leftover in the last byte */ *p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0); } static int __nvmem_cell_read(struct nvmem_device *nvmem, struct nvmem_cell *cell, void *buf, size_t *len) { int rc; rc = nvmem_reg_read(nvmem, cell->offset, buf, cell->bytes); if (rc) return rc; /* shift bits in-place */ if (cell->bit_offset || cell->nbits) nvmem_shift_read_buffer_in_place(cell, buf); if (len) *len = cell->bytes; return 0; } /** * nvmem_cell_read() - Read a given nvmem cell * * @cell: nvmem cell to be read. * @len: pointer to length of cell which will be populated on successful read; * can be NULL. * * Return: ERR_PTR() on error or a valid pointer to a buffer on success. The * buffer should be freed by the consumer with a kfree(). */ void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len) { struct nvmem_device *nvmem = cell->nvmem; u8 *buf; int rc; if (!nvmem) return ERR_PTR(-EINVAL); buf = kzalloc(cell->bytes, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); rc = __nvmem_cell_read(nvmem, cell, buf, len); if (rc) { kfree(buf); return ERR_PTR(rc); } return buf; } EXPORT_SYMBOL_GPL(nvmem_cell_read); static inline void *nvmem_cell_prepare_write_buffer(struct nvmem_cell *cell, u8 *_buf, int len) { struct nvmem_device *nvmem = cell->nvmem; int i, rc, nbits, bit_offset = cell->bit_offset; u8 v, *p, *buf, *b, pbyte, pbits; nbits = cell->nbits; buf = kzalloc(cell->bytes, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); memcpy(buf, _buf, len); p = b = buf; if (bit_offset) { pbyte = *b; *b <<= bit_offset; /* setup the first byte with lsb bits from nvmem */ rc = nvmem_reg_read(nvmem, cell->offset, &v, 1); *b++ |= GENMASK(bit_offset - 1, 0) & v; /* setup rest of the byte if any */ for (i = 1; i < cell->bytes; i++) { /* Get last byte bits and shift them towards lsb */ pbits = pbyte >> (BITS_PER_BYTE - 1 - bit_offset); pbyte = *b; p = b; *b <<= bit_offset; *b++ |= pbits; } } /* if it's not end on byte boundary */ if ((nbits + bit_offset) % BITS_PER_BYTE) { /* setup the last byte with msb bits from nvmem */ rc = nvmem_reg_read(nvmem, cell->offset + cell->bytes - 1, &v, 1); *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v; } return buf; } /** * nvmem_cell_write() - Write to a given nvmem cell * * @cell: nvmem cell to be written. * @buf: Buffer to be written. * @len: length of buffer to be written to nvmem cell. * * Return: length of bytes written or negative on failure. */ int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len) { struct nvmem_device *nvmem = cell->nvmem; int rc; if (!nvmem || nvmem->read_only || (cell->bit_offset == 0 && len != cell->bytes)) return -EINVAL; if (cell->bit_offset || cell->nbits) { buf = nvmem_cell_prepare_write_buffer(cell, buf, len); if (IS_ERR(buf)) return PTR_ERR(buf); } rc = nvmem_reg_write(nvmem, cell->offset, buf, cell->bytes); /* free the tmp buffer */ if (cell->bit_offset || cell->nbits) kfree(buf); if (rc) return rc; return len; } EXPORT_SYMBOL_GPL(nvmem_cell_write); /** * nvmem_cell_read_u32() - Read a cell value as an u32 * * @dev: Device that requests the nvmem cell. * @cell_id: Name of nvmem cell to read. * @val: pointer to output value. * * Return: 0 on success or negative errno. */ int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val) { struct nvmem_cell *cell; void *buf; size_t len; cell = nvmem_cell_get(dev, cell_id); if (IS_ERR(cell)) return PTR_ERR(cell); buf = nvmem_cell_read(cell, &len); if (IS_ERR(buf)) { nvmem_cell_put(cell); return PTR_ERR(buf); } if (len != sizeof(*val)) { kfree(buf); nvmem_cell_put(cell); return -EINVAL; } memcpy(val, buf, sizeof(*val)); kfree(buf); nvmem_cell_put(cell); return 0; } EXPORT_SYMBOL_GPL(nvmem_cell_read_u32); /** * nvmem_device_cell_read() - Read a given nvmem device and cell * * @nvmem: nvmem device to read from. * @info: nvmem cell info to be read. * @buf: buffer pointer which will be populated on successful read. * * Return: length of successful bytes read on success and negative * error code on error. */ ssize_t nvmem_device_cell_read(struct nvmem_device *nvmem, struct nvmem_cell_info *info, void *buf) { struct nvmem_cell cell; int rc; ssize_t len; if (!nvmem) return -EINVAL; rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell); if (rc) return rc; rc = __nvmem_cell_read(nvmem, &cell, buf, &len); if (rc) return rc; return len; } EXPORT_SYMBOL_GPL(nvmem_device_cell_read); /** * nvmem_device_cell_write() - Write cell to a given nvmem device * * @nvmem: nvmem device to be written to. * @info: nvmem cell info to be written. * @buf: buffer to be written to cell. * * Return: length of bytes written or negative error code on failure. * */ int nvmem_device_cell_write(struct nvmem_device *nvmem, struct nvmem_cell_info *info, void *buf) { struct nvmem_cell cell; int rc; if (!nvmem) return -EINVAL; rc = nvmem_cell_info_to_nvmem_cell(nvmem, info, &cell); if (rc) return rc; return nvmem_cell_write(&cell, buf, cell.bytes); } EXPORT_SYMBOL_GPL(nvmem_device_cell_write); /** * nvmem_device_read() - Read from a given nvmem device * * @nvmem: nvmem device to read from. * @offset: offset in nvmem device. * @bytes: number of bytes to read. * @buf: buffer pointer which will be populated on successful read. * * Return: length of successful bytes read on success and negative * error code on error. */ int nvmem_device_read(struct nvmem_device *nvmem, unsigned int offset, size_t bytes, void *buf) { int rc; if (!nvmem) return -EINVAL; rc = nvmem_reg_read(nvmem, offset, buf, bytes); if (rc) return rc; return bytes; } EXPORT_SYMBOL_GPL(nvmem_device_read); /** * nvmem_device_write() - Write cell to a given nvmem device * * @nvmem: nvmem device to be written to. * @offset: offset in nvmem device. * @bytes: number of bytes to write. * @buf: buffer to be written. * * Return: length of bytes written or negative error code on failure. * */ int nvmem_device_write(struct nvmem_device *nvmem, unsigned int offset, size_t bytes, void *buf) { int rc; if (!nvmem) return -EINVAL; rc = nvmem_reg_write(nvmem, offset, buf, bytes); if (rc) return rc; return bytes; } EXPORT_SYMBOL_GPL(nvmem_device_write); static int __init nvmem_init(void) { return bus_register(&nvmem_bus_type); } static void __exit nvmem_exit(void) { bus_unregister(&nvmem_bus_type); } subsys_initcall(nvmem_init); module_exit(nvmem_exit); MODULE_AUTHOR("Srinivas Kandagatla