[v8,1/9] nvmem: Add a simple NVMEM framework for nvmem providers

Message ID	1437403392-4136-1-git-send-email-srinivas.kandagatla@linaro.org (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org> From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> To: linux-arm-kernel@lists.infradead.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org> Subject: [PATCH v8 1/9] nvmem: Add a simple NVMEM framework for nvmem providers Date: Mon, 20 Jul 2015 15:43:12 +0100 Message-Id: <1437403392-4136-1-git-send-email-srinivas.kandagatla@linaro.org> In-Reply-To: <1437403352-4091-1-git-send-email-srinivas.kandagatla@linaro.org> References: <1437403352-4091-1-git-send-email-srinivas.kandagatla@linaro.org> Precedence: list Cc: stefan.wahren@i2se.com, devicetree@vger.kernel.org, arnd@arndb.de, linux-api@vger.kernel.org, s.hauer@pengutronix.de, sboyd@codeaurora.org, linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>, pantelis.antoniou@konsulko.com, Mark Brown <broonie@kernel.org>, Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, linux-arm-msm@vger.kernel.org, mporter@konsulko.com, Maxime Ripard <maxime.ripard@free-electrons.com>, wxt@rock-chips.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org> Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org

diff --git a/drivers/Kconfig b/drivers/Kconfig index 6e973b8..4e2e6aa 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -184,4 +184,6 @@ source "drivers/android/Kconfig" source "drivers/nvdimm/Kconfig" +source "drivers/nvmem/Kconfig" + endmenu diff --git a/drivers/Makefile b/drivers/Makefile index b64b49f..4c270f5 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -165,3 +165,4 @@ obj-$(CONFIG_RAS) += ras/ obj-$(CONFIG_THUNDERBOLT) += thunderbolt/ obj-$(CONFIG_CORESIGHT) += hwtracing/coresight/ obj-$(CONFIG_ANDROID) += android/ +obj-$(CONFIG_NVMEM) += nvmem/ diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig new file mode 100644 index 0000000..de90c82 --- /dev/null +++ b/drivers/nvmem/Kconfig @@ -0,0 +1,13 @@ +menuconfig NVMEM + tristate "NVMEM Support" + select REGMAP + help + Support for NVMEM(Non Volatile Memory) devices like EEPROM, EFUSES... + + This framework is designed to provide a generic interface to NVMEM + from both the Linux Kernel and the userspace. + + This driver can also be built as a module. If so, the module + will be called nvmem_core. + + If unsure, say no. diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile new file mode 100644 index 0000000..6df2c69 --- /dev/null +++ b/drivers/nvmem/Makefile @@ -0,0 +1,6 @@ +# +# Makefile for nvmem drivers. +# + +obj-$(CONFIG_NVMEM) += nvmem_core.o +nvmem_core-y := core.o diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c new file mode 100644 index 0000000..bde5528 --- /dev/null +++ b/drivers/nvmem/core.c @@ -0,0 +1,384 @@ +/* + * nvmem framework core. + * + * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org> + * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com> + * + * 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 <linux/device.h> +#include <linux/export.h> +#include <linux/fs.h> +#include <linux/idr.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/nvmem-consumer.h> +#include <linux/nvmem-provider.h> +#include <linux/of.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +struct nvmem_device { + const char *name; + struct regmap *regmap; + struct module *owner; + struct device dev; + int stride; + int word_size; + int ncells; + int id; + int users; + size_t size; + bool read_only; +}; + +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); + +#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev) + +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 = container_of(kobj, struct device, kobj); + struct nvmem_device *nvmem = to_nvmem_device(dev); + int rc; + + /* Stop the user from reading */ + if (pos > nvmem->size) + return 0; + + if (pos + count > nvmem->size) + count = nvmem->size - pos; + + count = round_down(count, nvmem->word_size); + + rc = regmap_raw_read(nvmem->regmap, pos, buf, count); + + if (IS_ERR_VALUE(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 = container_of(kobj, struct device, kobj); + struct nvmem_device *nvmem = to_nvmem_device(dev); + int rc; + + /* Stop the user from writing */ + if (pos > nvmem->size) + return 0; + + if (pos + count > nvmem->size) + count = nvmem->size - pos; + + count = round_down(count, nvmem->word_size); + + rc = regmap_raw_write(nvmem->regmap, pos, buf, count); + + if (IS_ERR_VALUE(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, +}; + +/* read only permission */ +static struct bin_attribute bin_attr_ro_nvmem = { + .attr = { + .name = "nvmem", + .mode = S_IRUGO, + }, + .read = bin_attr_nvmem_read, +}; + +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; + + list_for_each_entry(p, &nvmem_cells, node) + if (p && !strcmp(p->name, cell_id)) + return p; + + 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 = kzalloc(sizeof(*cells) * cfg->ncells, 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 (IS_ERR_VALUE(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]); + + return rval; +} + +/** + * 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; + struct regmap *rm; + int rval; + + if (!config->dev) + return ERR_PTR(-EINVAL); + + rm = dev_get_regmap(config->dev, NULL); + if (!rm) { + dev_err(config->dev, "Regmap not found\n"); + return ERR_PTR(-EINVAL); + } + + nvmem = kzalloc(sizeof(*nvmem), GFP_KERNEL); + if (!nvmem) + return ERR_PTR(-ENOMEM); + + nvmem->id = ida_simple_get(&nvmem_ida, 0, 0, GFP_KERNEL); + if (nvmem->id < 0) { + kfree(nvmem); + return ERR_PTR(nvmem->id); + } + + nvmem->regmap = rm; + nvmem->owner = config->owner; + nvmem->stride = regmap_get_reg_stride(rm); + nvmem->word_size = regmap_get_val_bytes(rm); + nvmem->size = regmap_get_max_register(rm) + nvmem->stride; + nvmem->dev.type = &nvmem_provider_type; + nvmem->dev.bus = &nvmem_bus_type; + nvmem->dev.parent = config->dev; + np = config->dev->of_node; + nvmem->dev.of_node = np; + dev_set_name(&nvmem->dev, "%s%d", + config->name ? : "nvmem", config->id); + + nvmem->read_only = np ? of_property_read_bool(np, "read-only") : 0; + + nvmem->read_only |= config->read_only; + + device_initialize(&nvmem->dev); + + dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name); + + rval = device_add(&nvmem->dev); + if (rval) { + ida_simple_remove(&nvmem_ida, nvmem->id); + kfree(nvmem); + return ERR_PTR(rval); + } + + if (device_create_bin_file(&nvmem->dev, + nvmem->read_only ? &bin_attr_ro_nvmem : + &bin_attr_rw_nvmem)) + dev_warn(&nvmem->dev, "Failed to create sysfs binary file\n"); + + if (config->cells) + nvmem_add_cells(nvmem, config); + + return nvmem; +} +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); + + nvmem_device_remove_all_cells(nvmem); + device_del(&nvmem->dev); + + return 0; +} +EXPORT_SYMBOL_GPL(nvmem_unregister); + +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"); diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h new file mode 100644 index 0000000..1e9e767 --- /dev/null +++ b/include/linux/nvmem-consumer.h @@ -0,0 +1,23 @@ +/* + * nvmem framework consumer. + * + * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org> + * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#ifndef _LINUX_NVMEM_CONSUMER_H +#define _LINUX_NVMEM_CONSUMER_H + +struct nvmem_cell_info { + const char *name; + unsigned int offset; + unsigned int bytes; + unsigned int bit_offset; + unsigned int nbits; +}; + +#endif /* ifndef _LINUX_NVMEM_CONSUMER_H */ diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h new file mode 100644 index 0000000..0b68caf --- /dev/null +++ b/include/linux/nvmem-provider.h @@ -0,0 +1,47 @@ +/* + * nvmem framework provider. + * + * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org> + * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#ifndef _LINUX_NVMEM_PROVIDER_H +#define _LINUX_NVMEM_PROVIDER_H + +struct nvmem_device; +struct nvmem_cell_info; + +struct nvmem_config { + struct device *dev; + const char *name; + int id; + struct module *owner; + const struct nvmem_cell_info *cells; + int ncells; + bool read_only; +}; + +#if IS_ENABLED(CONFIG_NVMEM) + +struct nvmem_device *nvmem_register(const struct nvmem_config *cfg); +int nvmem_unregister(struct nvmem_device *nvmem); + +#else + +static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c) +{ + return ERR_PTR(-ENOSYS); +} + +static inline int nvmem_unregister(struct nvmem_device *nvmem) +{ + return -ENOSYS; +} + +#endif /* CONFIG_NVMEM */ + +#endif /* ifndef _LINUX_NVMEM_PROVIDER_H */

[v8,1/9] nvmem: Add a simple NVMEM framework for nvmem providers

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