diff options
Diffstat (limited to 'drivers/nvmem/core.c')
| -rw-r--r-- | drivers/nvmem/core.c | 1677 |
1 files changed, 1677 insertions, 0 deletions
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c new file mode 100644 index 000000000..1505c7451 --- /dev/null +++ b/drivers/nvmem/core.c @@ -0,0 +1,1677 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * nvmem framework core. + * + * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org> + * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com> + */ + +#include <linux/device.h> +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/idr.h> +#include <linux/init.h> +#include <linux/kref.h> +#include <linux/module.h> +#include <linux/nvmem-consumer.h> +#include <linux/nvmem-provider.h> +#include <linux/gpio/consumer.h> +#include <linux/of.h> +#include <linux/slab.h> + +struct nvmem_device { + struct module *owner; + struct device dev; + int stride; + int word_size; + int id; + struct kref refcnt; + size_t size; + bool read_only; + bool root_only; + int flags; + enum nvmem_type type; + struct bin_attribute eeprom; + struct device *base_dev; + struct list_head cells; + nvmem_reg_read_t reg_read; + nvmem_reg_write_t reg_write; + struct gpio_desc *wp_gpio; + void *priv; +}; + +#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev) + +#define FLAG_COMPAT BIT(0) + +struct nvmem_cell { + const char *name; + int offset; + int bytes; + int bit_offset; + int nbits; + struct device_node *np; + struct nvmem_device *nvmem; + struct list_head node; +}; + +static DEFINE_MUTEX(nvmem_mutex); +static DEFINE_IDA(nvmem_ida); + +static DEFINE_MUTEX(nvmem_cell_mutex); +static LIST_HEAD(nvmem_cell_tables); + +static DEFINE_MUTEX(nvmem_lookup_mutex); +static LIST_HEAD(nvmem_lookup_list); + +static BLOCKING_NOTIFIER_HEAD(nvmem_notifier); + +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) +{ + int ret; + + if (nvmem->reg_write) { + gpiod_set_value_cansleep(nvmem->wp_gpio, 0); + ret = nvmem->reg_write(nvmem->priv, offset, val, bytes); + gpiod_set_value_cansleep(nvmem->wp_gpio, 1); + return ret; + } + + return -EINVAL; +} + +#ifdef CONFIG_NVMEM_SYSFS +static const char * const nvmem_type_str[] = { + [NVMEM_TYPE_UNKNOWN] = "Unknown", + [NVMEM_TYPE_EEPROM] = "EEPROM", + [NVMEM_TYPE_OTP] = "OTP", + [NVMEM_TYPE_BATTERY_BACKED] = "Battery backed", +}; + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +static struct lock_class_key eeprom_lock_key; +#endif + +static ssize_t type_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct nvmem_device *nvmem = to_nvmem_device(dev); + + return sprintf(buf, "%s\n", nvmem_type_str[nvmem->type]); +} + +static DEVICE_ATTR_RO(type); + +static struct attribute *nvmem_attrs[] = { + &dev_attr_type.attr, + NULL, +}; + +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 = kobj_to_dev(kobj); + nvmem = to_nvmem_device(dev); + + /* Stop the user from reading */ + if (pos >= nvmem->size) + return 0; + + if (!IS_ALIGNED(pos, nvmem->stride)) + return -EINVAL; + + if (count < nvmem->word_size) + return -EINVAL; + + if (pos + count > nvmem->size) + count = nvmem->size - pos; + + count = round_down(count, nvmem->word_size); + + if (!nvmem->reg_read) + return -EPERM; + + 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 = kobj_to_dev(kobj); + nvmem = to_nvmem_device(dev); + + /* Stop the user from writing */ + if (pos >= nvmem->size) + return -EFBIG; + + if (!IS_ALIGNED(pos, nvmem->stride)) + return -EINVAL; + + if (count < nvmem->word_size) + return -EINVAL; + + if (pos + count > nvmem->size) + count = nvmem->size - pos; + + count = round_down(count, nvmem->word_size); + + if (!nvmem->reg_write) + return -EPERM; + + rc = nvmem_reg_write(nvmem, pos, buf, count); + + if (rc) + return rc; + + return count; +} + +static umode_t nvmem_bin_attr_get_umode(struct nvmem_device *nvmem) +{ + umode_t mode = 0400; + + if (!nvmem->root_only) + mode |= 0044; + + if (!nvmem->read_only) + mode |= 0200; + + if (!nvmem->reg_write) + mode &= ~0200; + + if (!nvmem->reg_read) + mode &= ~0444; + + return mode; +} + +static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj, + struct bin_attribute *attr, int i) +{ + struct device *dev = kobj_to_dev(kobj); + struct nvmem_device *nvmem = to_nvmem_device(dev); + + attr->size = nvmem->size; + + return nvmem_bin_attr_get_umode(nvmem); +} + +/* default read/write permissions */ +static struct bin_attribute bin_attr_rw_nvmem = { + .attr = { + .name = "nvmem", + .mode = 0644, + }, + .read = bin_attr_nvmem_read, + .write = bin_attr_nvmem_write, +}; + +static struct bin_attribute *nvmem_bin_attributes[] = { + &bin_attr_rw_nvmem, + NULL, +}; + +static const struct attribute_group nvmem_bin_group = { + .bin_attrs = nvmem_bin_attributes, + .attrs = nvmem_attrs, + .is_bin_visible = nvmem_bin_attr_is_visible, +}; + +static const struct attribute_group *nvmem_dev_groups[] = { + &nvmem_bin_group, + NULL, +}; + +static struct bin_attribute bin_attr_nvmem_eeprom_compat = { + .attr = { + .name = "eeprom", + }, + .read = bin_attr_nvmem_read, + .write = bin_attr_nvmem_write, +}; + +/* + * 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_sysfs_setup_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ + int rval; + + if (!config->compat) + return 0; + + if (!config->base_dev) + return -EINVAL; + + nvmem->eeprom = bin_attr_nvmem_eeprom_compat; + nvmem->eeprom.attr.mode = nvmem_bin_attr_get_umode(nvmem); + 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; +} + +static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ + if (config->compat) + device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); +} + +#else /* CONFIG_NVMEM_SYSFS */ + +static int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ + return -ENOSYS; +} +static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ +} + +#endif /* CONFIG_NVMEM_SYSFS */ + +static void nvmem_release(struct device *dev) +{ + struct nvmem_device *nvmem = to_nvmem_device(dev); + + ida_free(&nvmem_ida, nvmem->id); + gpiod_put(nvmem->wp_gpio); + kfree(nvmem); +} + +static const struct device_type nvmem_provider_type = { + .release = nvmem_release, +}; + +static struct bus_type nvmem_bus_type = { + .name = "nvmem", +}; + +static void nvmem_cell_drop(struct nvmem_cell *cell) +{ + blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_REMOVE, cell); + mutex_lock(&nvmem_mutex); + list_del(&cell->node); + mutex_unlock(&nvmem_mutex); + of_node_put(cell->np); + kfree_const(cell->name); + kfree(cell); +} + +static void nvmem_device_remove_all_cells(const struct nvmem_device *nvmem) +{ + struct nvmem_cell *cell, *p; + + list_for_each_entry_safe(cell, p, &nvmem->cells, node) + nvmem_cell_drop(cell); +} + +static void nvmem_cell_add(struct nvmem_cell *cell) +{ + mutex_lock(&nvmem_mutex); + list_add_tail(&cell->node, &cell->nvmem->cells); + mutex_unlock(&nvmem_mutex); + blocking_notifier_call_chain(&nvmem_notifier, NVMEM_CELL_ADD, cell); +} + +static int nvmem_cell_info_to_nvmem_cell_nodup(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 ?: "<unknown>", nvmem->stride); + return -EINVAL; + } + + return 0; +} + +static int nvmem_cell_info_to_nvmem_cell(struct nvmem_device *nvmem, + const struct nvmem_cell_info *info, + struct nvmem_cell *cell) +{ + int err; + + err = nvmem_cell_info_to_nvmem_cell_nodup(nvmem, info, cell); + if (err) + return err; + + cell->name = kstrdup_const(info->name, GFP_KERNEL); + if (!cell->name) + return -ENOMEM; + + return 0; +} + +/** + * nvmem_add_cells() - Add cell information to an nvmem device + * + * @nvmem: nvmem device to add cells to. + * @info: nvmem cell info to add to the device + * @ncells: number of cells in info + * + * Return: 0 or negative error code on failure. + */ +static int nvmem_add_cells(struct nvmem_device *nvmem, + const struct nvmem_cell_info *info, + int ncells) +{ + struct nvmem_cell **cells; + int i, rval; + + cells = kcalloc(ncells, sizeof(*cells), GFP_KERNEL); + if (!cells) + return -ENOMEM; + + for (i = 0; i < 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]); + } + + /* remove tmp array */ + kfree(cells); + + return 0; +err: + while (i--) + nvmem_cell_drop(cells[i]); + + kfree(cells); + + return rval; +} + +/** + * nvmem_register_notifier() - Register a notifier block for nvmem events. + * + * @nb: notifier block to be called on nvmem events. + * + * Return: 0 on success, negative error number on failure. + */ +int nvmem_register_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&nvmem_notifier, nb); +} +EXPORT_SYMBOL_GPL(nvmem_register_notifier); + +/** + * nvmem_unregister_notifier() - Unregister a notifier block for nvmem events. + * + * @nb: notifier block to be unregistered. + * + * Return: 0 on success, negative error number on failure. + */ +int nvmem_unregister_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&nvmem_notifier, nb); +} +EXPORT_SYMBOL_GPL(nvmem_unregister_notifier); + +static int nvmem_add_cells_from_table(struct nvmem_device *nvmem) +{ + const struct nvmem_cell_info *info; + struct nvmem_cell_table *table; + struct nvmem_cell *cell; + int rval = 0, i; + + mutex_lock(&nvmem_cell_mutex); + list_for_each_entry(table, &nvmem_cell_tables, node) { + if (strcmp(nvmem_dev_name(nvmem), table->nvmem_name) == 0) { + for (i = 0; i < table->ncells; i++) { + info = &table->cells[i]; + + cell = kzalloc(sizeof(*cell), GFP_KERNEL); + if (!cell) { + rval = -ENOMEM; + goto out; + } + + rval = nvmem_cell_info_to_nvmem_cell(nvmem, + info, + cell); + if (rval) { + kfree(cell); + goto out; + } + + nvmem_cell_add(cell); + } + } + } + +out: + mutex_unlock(&nvmem_cell_mutex); + return rval; +} + +static struct nvmem_cell * +nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id) +{ + struct nvmem_cell *iter, *cell = NULL; + + mutex_lock(&nvmem_mutex); + list_for_each_entry(iter, &nvmem->cells, node) { + if (strcmp(cell_id, iter->name) == 0) { + cell = iter; + break; + } + } + mutex_unlock(&nvmem_mutex); + + return cell; +} + +static int nvmem_add_cells_from_of(struct nvmem_device *nvmem) +{ + struct device_node *parent, *child; + struct device *dev = &nvmem->dev; + struct nvmem_cell *cell; + const __be32 *addr; + int len; + + parent = dev->of_node; + + for_each_child_of_node(parent, child) { + addr = of_get_property(child, "reg", &len); + if (!addr) + continue; + if (len < 2 * sizeof(u32)) { + dev_err(dev, "nvmem: invalid reg on %pOF\n", child); + of_node_put(child); + return -EINVAL; + } + + cell = kzalloc(sizeof(*cell), GFP_KERNEL); + if (!cell) { + of_node_put(child); + return -ENOMEM; + } + + cell->nvmem = nvmem; + cell->offset = be32_to_cpup(addr++); + cell->bytes = be32_to_cpup(addr); + cell->name = kasprintf(GFP_KERNEL, "%pOFn", child); + + addr = of_get_property(child, "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(dev, "cell %s unaligned to nvmem stride %d\n", + cell->name, nvmem->stride); + /* Cells already added will be freed later. */ + kfree_const(cell->name); + kfree(cell); + of_node_put(child); + return -EINVAL; + } + + cell->np = of_node_get(child); + nvmem_cell_add(cell); + } + + return 0; +} + +/** + * nvmem_register() - Register a nvmem device for given nvmem_config. + * Also creates a 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; + int rval; + + if (!config->dev) + return ERR_PTR(-EINVAL); + + if (!config->reg_read && !config->reg_write) + return ERR_PTR(-EINVAL); + + nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL); + if (!nvmem) + return ERR_PTR(-ENOMEM); + + rval = ida_alloc(&nvmem_ida, GFP_KERNEL); + if (rval < 0) { + kfree(nvmem); + return ERR_PTR(rval); + } + + nvmem->id = rval; + + nvmem->dev.type = &nvmem_provider_type; + nvmem->dev.bus = &nvmem_bus_type; + nvmem->dev.parent = config->dev; + + device_initialize(&nvmem->dev); + + if (!config->ignore_wp) + nvmem->wp_gpio = gpiod_get_optional(config->dev, "wp", + GPIOD_OUT_HIGH); + if (IS_ERR(nvmem->wp_gpio)) { + rval = PTR_ERR(nvmem->wp_gpio); + nvmem->wp_gpio = NULL; + goto err_put_device; + } + + kref_init(&nvmem->refcnt); + INIT_LIST_HEAD(&nvmem->cells); + + nvmem->owner = config->owner; + if (!nvmem->owner && config->dev->driver) + nvmem->owner = config->dev->driver->owner; + nvmem->stride = config->stride ?: 1; + nvmem->word_size = config->word_size ?: 1; + nvmem->size = config->size; + nvmem->root_only = config->root_only; + nvmem->priv = config->priv; + nvmem->type = config->type; + nvmem->reg_read = config->reg_read; + nvmem->reg_write = config->reg_write; + if (!config->no_of_node) + nvmem->dev.of_node = config->dev->of_node; + + switch (config->id) { + case NVMEM_DEVID_NONE: + rval = dev_set_name(&nvmem->dev, "%s", config->name); + break; + case NVMEM_DEVID_AUTO: + rval = dev_set_name(&nvmem->dev, "%s%d", config->name, nvmem->id); + break; + default: + rval = dev_set_name(&nvmem->dev, "%s%d", + config->name ? : "nvmem", + config->name ? config->id : nvmem->id); + break; + } + + if (rval) + goto err_put_device; + + nvmem->read_only = device_property_present(config->dev, "read-only") || + config->read_only || !nvmem->reg_write; + +#ifdef CONFIG_NVMEM_SYSFS + nvmem->dev.groups = nvmem_dev_groups; +#endif + + if (config->compat) { + rval = nvmem_sysfs_setup_compat(nvmem, config); + if (rval) + goto err_put_device; + } + + if (config->cells) { + rval = nvmem_add_cells(nvmem, config->cells, config->ncells); + if (rval) + goto err_remove_cells; + } + + rval = nvmem_add_cells_from_table(nvmem); + if (rval) + goto err_remove_cells; + + rval = nvmem_add_cells_from_of(nvmem); + if (rval) + goto err_remove_cells; + + dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name); + + rval = device_add(&nvmem->dev); + if (rval) + goto err_remove_cells; + + blocking_notifier_call_chain(&nvmem_notifier, NVMEM_ADD, nvmem); + + return nvmem; + +err_remove_cells: + nvmem_device_remove_all_cells(nvmem); + if (config->compat) + nvmem_sysfs_remove_compat(nvmem, config); +err_put_device: + put_device(&nvmem->dev); + + return ERR_PTR(rval); +} +EXPORT_SYMBOL_GPL(nvmem_register); + +static void nvmem_device_release(struct kref *kref) +{ + struct nvmem_device *nvmem; + + nvmem = container_of(kref, struct nvmem_device, refcnt); + + blocking_notifier_call_chain(&nvmem_notifier, NVMEM_REMOVE, nvmem); + + if (nvmem->flags & FLAG_COMPAT) + device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); + + nvmem_device_remove_all_cells(nvmem); + device_unregister(&nvmem->dev); +} + +/** + * nvmem_unregister() - Unregister previously registered nvmem device + * + * @nvmem: Pointer to previously registered nvmem device. + */ +void nvmem_unregister(struct nvmem_device *nvmem) +{ + kref_put(&nvmem->refcnt, nvmem_device_release); +} +EXPORT_SYMBOL_GPL(nvmem_unregister); + +static void devm_nvmem_release(struct device *dev, void *res) +{ + nvmem_unregister(*(struct nvmem_device **)res); +} + +/** + * devm_nvmem_register() - Register a managed nvmem device for given + * nvmem_config. + * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem + * + * @dev: Device that uses the nvmem device. + * @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 *devm_nvmem_register(struct device *dev, + const struct nvmem_config *config) +{ + struct nvmem_device **ptr, *nvmem; + + ptr = devres_alloc(devm_nvmem_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + nvmem = nvmem_register(config); + + if (!IS_ERR(nvmem)) { + *ptr = nvmem; + devres_add(dev, ptr); + } else { + devres_free(ptr); + } + + return nvmem; +} +EXPORT_SYMBOL_GPL(devm_nvmem_register); + +static int devm_nvmem_match(struct device *dev, void *res, void *data) +{ + struct nvmem_device **r = res; + + return *r == data; +} + +/** + * devm_nvmem_unregister() - Unregister previously registered managed nvmem + * device. + * + * @dev: Device that uses the nvmem device. + * @nvmem: Pointer to previously registered nvmem device. + * + * Return: Will be negative on error or zero on success. + */ +int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem) +{ + return devres_release(dev, devm_nvmem_release, devm_nvmem_match, nvmem); +} +EXPORT_SYMBOL(devm_nvmem_unregister); + +static struct nvmem_device *__nvmem_device_get(void *data, + int (*match)(struct device *dev, const void *data)) +{ + struct nvmem_device *nvmem = NULL; + struct device *dev; + + mutex_lock(&nvmem_mutex); + dev = bus_find_device(&nvmem_bus_type, NULL, data, match); + if (dev) + nvmem = to_nvmem_device(dev); + mutex_unlock(&nvmem_mutex); + if (!nvmem) + return ERR_PTR(-EPROBE_DEFER); + + if (!try_module_get(nvmem->owner)) { + dev_err(&nvmem->dev, + "could not increase module refcount for cell %s\n", + nvmem_dev_name(nvmem)); + + put_device(&nvmem->dev); + return ERR_PTR(-EINVAL); + } + + kref_get(&nvmem->refcnt); + + return nvmem; +} + +static void __nvmem_device_put(struct nvmem_device *nvmem) +{ + put_device(&nvmem->dev); + module_put(nvmem->owner); + kref_put(&nvmem->refcnt, nvmem_device_release); +} + +#if 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; + struct nvmem_device *nvmem; + int index = 0; + + if (id) + index = of_property_match_string(np, "nvmem-names", id); + + nvmem_np = of_parse_phandle(np, "nvmem", index); + if (!nvmem_np) + return ERR_PTR(-ENOENT); + + nvmem = __nvmem_device_get(nvmem_np, device_match_of_node); + of_node_put(nvmem_np); + return nvmem; +} +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_device_get((void *)dev_name, device_match_name); +} +EXPORT_SYMBOL_GPL(nvmem_device_get); + +/** + * nvmem_device_find() - Find nvmem device with matching function + * + * @data: Data to pass to match function + * @match: Callback function to check device + * + * Return: ERR_PTR() on error or a valid pointer to a struct nvmem_device + * on success. + */ +struct nvmem_device *nvmem_device_find(void *data, + int (*match)(struct device *dev, const void *data)) +{ + return __nvmem_device_get(data, match); +} +EXPORT_SYMBOL_GPL(nvmem_device_find); + +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_lookup(struct device *dev, const char *con_id) +{ + struct nvmem_cell *cell = ERR_PTR(-ENOENT); + struct nvmem_cell_lookup *lookup; + struct nvmem_device *nvmem; + const char *dev_id; + + if (!dev) + return ERR_PTR(-EINVAL); + + dev_id = dev_name(dev); + + mutex_lock(&nvmem_lookup_mutex); + + list_for_each_entry(lookup, &nvmem_lookup_list, node) { + if ((strcmp(lookup->dev_id, dev_id) == 0) && + (strcmp(lookup->con_id, con_id) == 0)) { + /* This is the right entry. */ + nvmem = __nvmem_device_get((void *)lookup->nvmem_name, + device_match_name); + if (IS_ERR(nvmem)) { + /* Provider may not be registered yet. */ + cell = ERR_CAST(nvmem); + break; + } + + cell = nvmem_find_cell_by_name(nvmem, + lookup->cell_name); + if (!cell) { + __nvmem_device_put(nvmem); + cell = ERR_PTR(-ENOENT); + } + break; + } + } + + mutex_unlock(&nvmem_lookup_mutex); + return cell; +} + +#if IS_ENABLED(CONFIG_OF) +static struct nvmem_cell * +nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np) +{ + struct nvmem_cell *iter, *cell = NULL; + + mutex_lock(&nvmem_mutex); + list_for_each_entry(iter, &nvmem->cells, node) { + if (np == iter->np) { + cell = iter; + break; + } + } + mutex_unlock(&nvmem_mutex); + + return cell; +} + +/** + * of_nvmem_cell_get() - Get a nvmem cell from given device node and cell id + * + * @np: Device tree node that uses the nvmem cell. + * @id: 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 *id) +{ + struct device_node *cell_np, *nvmem_np; + struct nvmem_device *nvmem; + struct nvmem_cell *cell; + int index = 0; + + /* if cell name exists, find index to the name */ + if (id) + index = of_property_match_string(np, "nvmem-cell-names", id); + + cell_np = of_parse_phandle(np, "nvmem-cells", index); + if (!cell_np) + return ERR_PTR(-ENOENT); + + nvmem_np = of_get_next_parent(cell_np); + if (!nvmem_np) + return ERR_PTR(-EINVAL); + + nvmem = __nvmem_device_get(nvmem_np, device_match_of_node); + of_node_put(nvmem_np); + if (IS_ERR(nvmem)) + return ERR_CAST(nvmem); + + cell = nvmem_find_cell_by_node(nvmem, cell_np); + if (!cell) { + __nvmem_device_put(nvmem); + return ERR_PTR(-ENOENT); + } + + return cell; +} +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. + * @id: nvmem cell name to get (this corresponds with the name from the + * nvmem-cell-names property for DT systems and with the con_id from + * the lookup entry for non-DT systems). + * + * 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 *id) +{ + struct nvmem_cell *cell; + + if (dev->of_node) { /* try dt first */ + cell = of_nvmem_cell_get(dev->of_node, id); + if (!IS_ERR(cell) || PTR_ERR(cell) == -EPROBE_DEFER) + return cell; + } + + /* NULL cell id only allowed for device tree; invalid otherwise */ + if (!id) + return ERR_PTR(-EINVAL); + + return nvmem_cell_get_from_lookup(dev, 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); +} +EXPORT_SYMBOL_GPL(nvmem_cell_put); + +static void nvmem_shift_read_buffer_in_place(struct nvmem_cell *cell, void *buf) +{ + u8 *p, *b; + int i, extra, 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; + } + } else { + /* point to the msb */ + p += cell->bytes - 1; + } + + /* result fits in less bytes */ + extra = cell->bytes - DIV_ROUND_UP(cell->nbits, BITS_PER_BYTE); + while (--extra >= 0) + *p-- = 0; + + /* clear msb bits if any leftover in the last byte */ + if (cell->nbits % BITS_PER_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 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); + if (rc) + goto err; + *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); + if (rc) + goto err; + *p |= GENMASK(7, (nbits + bit_offset) % BITS_PER_BYTE) & v; + + } + + return buf; +err: + kfree(buf); + return ERR_PTR(rc); +} + +/** + * 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); + +static int nvmem_cell_read_common(struct device *dev, const char *cell_id, + void *val, size_t count) +{ + 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 != count) { + kfree(buf); + nvmem_cell_put(cell); + return -EINVAL; + } + memcpy(val, buf, count); + kfree(buf); + nvmem_cell_put(cell); + + return 0; +} + +/** + * nvmem_cell_read_u8() - Read a cell value as a u8 + * + * @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_u8(struct device *dev, const char *cell_id, u8 *val) +{ + return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); +} +EXPORT_SYMBOL_GPL(nvmem_cell_read_u8); + +/** + * nvmem_cell_read_u16() - Read a cell value as a u16 + * + * @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_u16(struct device *dev, const char *cell_id, u16 *val) +{ + return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); +} +EXPORT_SYMBOL_GPL(nvmem_cell_read_u16); + +/** + * nvmem_cell_read_u32() - Read a cell value as a 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) +{ + return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); +} +EXPORT_SYMBOL_GPL(nvmem_cell_read_u32); + +/** + * nvmem_cell_read_u64() - Read a cell value as a u64 + * + * @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_u64(struct device *dev, const char *cell_id, u64 *val) +{ + return nvmem_cell_read_common(dev, cell_id, val, sizeof(*val)); +} +EXPORT_SYMBOL_GPL(nvmem_cell_read_u64); + +/** + * 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_nodup(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_nodup(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); + +/** + * nvmem_add_cell_table() - register a table of cell info entries + * + * @table: table of cell info entries + */ +void nvmem_add_cell_table(struct nvmem_cell_table *table) +{ + mutex_lock(&nvmem_cell_mutex); + list_add_tail(&table->node, &nvmem_cell_tables); + mutex_unlock(&nvmem_cell_mutex); +} +EXPORT_SYMBOL_GPL(nvmem_add_cell_table); + +/** + * nvmem_del_cell_table() - remove a previously registered cell info table + * + * @table: table of cell info entries + */ +void nvmem_del_cell_table(struct nvmem_cell_table *table) +{ + mutex_lock(&nvmem_cell_mutex); + list_del(&table->node); + mutex_unlock(&nvmem_cell_mutex); +} +EXPORT_SYMBOL_GPL(nvmem_del_cell_table); + +/** + * nvmem_add_cell_lookups() - register a list of cell lookup entries + * + * @entries: array of cell lookup entries + * @nentries: number of cell lookup entries in the array + */ +void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) +{ + int i; + + mutex_lock(&nvmem_lookup_mutex); + for (i = 0; i < nentries; i++) + list_add_tail(&entries[i].node, &nvmem_lookup_list); + mutex_unlock(&nvmem_lookup_mutex); +} +EXPORT_SYMBOL_GPL(nvmem_add_cell_lookups); + +/** + * nvmem_del_cell_lookups() - remove a list of previously added cell lookup + * entries + * + * @entries: array of cell lookup entries + * @nentries: number of cell lookup entries in the array + */ +void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) +{ + int i; + + mutex_lock(&nvmem_lookup_mutex); + for (i = 0; i < nentries; i++) + list_del(&entries[i].node); + mutex_unlock(&nvmem_lookup_mutex); +} +EXPORT_SYMBOL_GPL(nvmem_del_cell_lookups); + +/** + * nvmem_dev_name() - Get the name of a given nvmem device. + * + * @nvmem: nvmem device. + * + * Return: name of the nvmem device. + */ +const char *nvmem_dev_name(struct nvmem_device *nvmem) +{ + return dev_name(&nvmem->dev); +} +EXPORT_SYMBOL_GPL(nvmem_dev_name); + +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 <srinivas.kandagatla@linaro.org"); +MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com"); +MODULE_DESCRIPTION("nvmem Driver Core"); +MODULE_LICENSE("GPL v2"); |