From 434446e79405aed78acd67221aa39675b52cbd25 Mon Sep 17 00:00:00 2001 From: Srinivas Kandagatla Date: Tue, 16 Apr 2019 10:59:24 +0100 Subject: [PATCH] BACKPORT: nvmem: core: add NVMEM_SYSFS Kconfig Many nvmem providers are not very keen on having default sysfs nvmem entry, as most of the usecases for them are inside kernel itself. And in some cases read/writes to some areas in nvmem are restricted and trapped at secure monitor level, so accessing them from userspace would result in board reboots. This patch adds new NVMEM_SYSFS Kconfig to make binary sysfs entry an optional one. This provision will give more flexibility to users. This patch also moves existing sysfs code to a new file so that its not compiled in when its not really required. Bug: 154188491 Signed-off-by: Srinivas Kandagatla Reviewed-by: Mika Westerberg Reviewed-by: Gaurav Kohli Tested-by: Gaurav Kohli Signed-off-by: Greg Kroah-Hartman (cherry picked from commit ae0c2d725512f32a0d1a25f0cf2f07616d33a72e) Signed-off-by: Will McVicker [willmcvicker: resolved trivial merge conflicts] Change-Id: I648edb8d43fc7c2437c415b999c41657a6d11554 --- Documentation/ABI/stable/sysfs-bus-nvmem | 2 + drivers/nvmem/Kconfig | 10 + drivers/nvmem/Makefile | 3 + drivers/nvmem/core.c | 303 +++-------------------- drivers/nvmem/nvmem-sysfs.c | 230 +++++++++++++++++ drivers/nvmem/nvmem.h | 62 +++++ 6 files changed, 340 insertions(+), 270 deletions(-) create mode 100644 drivers/nvmem/nvmem-sysfs.c create mode 100644 drivers/nvmem/nvmem.h diff --git a/Documentation/ABI/stable/sysfs-bus-nvmem b/Documentation/ABI/stable/sysfs-bus-nvmem index 5923ab4620c5..9ffba8576f7b 100644 --- a/Documentation/ABI/stable/sysfs-bus-nvmem +++ b/Documentation/ABI/stable/sysfs-bus-nvmem @@ -6,6 +6,8 @@ Description: This file allows user to read/write the raw NVMEM contents. Permissions for write to this file depends on the nvmem provider configuration. + Note: This file is only present if CONFIG_NVMEM_SYSFS + is enabled ex: hexdump /sys/bus/nvmem/devices/qfprom0/nvmem diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 0a7a470ee859..bd881c4e816d 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -13,6 +13,16 @@ menuconfig NVMEM if NVMEM +config NVMEM_SYSFS + bool "/sys/bus/nvmem/devices/*/nvmem (sysfs interface)" + depends on SYSFS + default y + help + Say Y here to add a sysfs interface for NVMEM. + + This interface is mostly used by userspace applications to + read/write directly into nvmem. + config NVMEM_IMX_IIM tristate "i.MX IC Identification Module support" depends on ARCH_MXC || COMPILE_TEST diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 4e8c61628f1a..1847ec17e97d 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -6,6 +6,9 @@ obj-$(CONFIG_NVMEM) += nvmem_core.o nvmem_core-y := core.o +obj-$(CONFIG_NVMEM_SYSFS) += nvmem_sysfs.o +nvmem_sysfs-y := nvmem-sysfs.o + # Devices obj-$(CONFIG_NVMEM_BCM_OCOTP) += nvmem-bcm-ocotp.o nvmem-bcm-ocotp-y := bcm-ocotp.o diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index fcd46418f338..f40ef8ea6ab5 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -26,26 +26,7 @@ #include #include -struct nvmem_device { - const char *name; - struct module *owner; - struct device dev; - int stride; - int word_size; - int id; - struct kref refcnt; - size_t size; - bool read_only; - int flags; - struct bin_attribute eeprom; - struct device *base_dev; - struct list_head cells; - nvmem_reg_read_t reg_read; - nvmem_reg_write_t reg_write; - void *priv; -}; - -#define FLAG_COMPAT BIT(0) +#include "nvmem.h" struct nvmem_cell { const char *name; @@ -64,11 +45,6 @@ static DEFINE_IDA(nvmem_ida); static DEFINE_MUTEX(nvmem_cell_mutex); static LIST_HEAD(nvmem_cell_tables); -#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) { @@ -87,168 +63,6 @@ static int nvmem_reg_write(struct nvmem_device *nvmem, unsigned int offset, 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 -EFBIG; - - 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); @@ -385,48 +199,41 @@ err: } EXPORT_SYMBOL_GPL(nvmem_add_cells); -/* - * 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) +static int nvmem_add_cells_from_table(struct nvmem_device *nvmem) { - int rval; + const struct nvmem_cell_info *info; + struct nvmem_cell_table *table; + struct nvmem_cell *cell; + int rval = 0, i; - if (!config->base_dev) - return -EINVAL; + 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]; - if (nvmem->read_only) { - if (config->root_only) - nvmem->eeprom = bin_attr_ro_root_nvmem; - else - nvmem->eeprom = bin_attr_ro_nvmem; - } else { - if (config->root_only) - nvmem->eeprom = bin_attr_rw_root_nvmem; - else - nvmem->eeprom = bin_attr_rw_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; + cell = kzalloc(sizeof(*cell), GFP_KERNEL); + if (!cell) { + rval = -ENOMEM; + goto out; + } - 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; + rval = nvmem_cell_info_to_nvmem_cell(nvmem, + info, + cell); + if (rval) { + kfree(cell); + goto out; + } + + nvmem_cell_add(cell); + } + } } - nvmem->flags |= FLAG_COMPAT; - - return 0; +out: + mutex_unlock(&nvmem_cell_mutex); + return rval; } static int nvmem_add_cells_from_of(struct nvmem_device *nvmem) @@ -481,43 +288,6 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem) return 0; } -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; -} - /** * nvmem_register() - Register a nvmem device for given nvmem_config. * Also creates an binary entry in /sys/bus/nvmem/devices/dev-name/nvmem @@ -575,14 +345,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) nvmem->read_only = device_property_present(config->dev, "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; + nvmem->dev.groups = nvmem_sysfs_get_groups(nvmem, config); device_initialize(&nvmem->dev); @@ -593,7 +356,7 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) goto err_put_device; if (config->compat) { - rval = nvmem_setup_compat(nvmem, config); + rval = nvmem_sysfs_setup_compat(nvmem, config); if (rval) goto err_device_del; } @@ -618,7 +381,7 @@ err_remove_cells: nvmem_device_remove_all_cells(nvmem); err_teardown_compat: if (config->compat) - device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); + nvmem_sysfs_remove_compat(nvmem, config); err_device_del: device_del(&nvmem->dev); err_put_device: diff --git a/drivers/nvmem/nvmem-sysfs.c b/drivers/nvmem/nvmem-sysfs.c new file mode 100644 index 000000000000..978bacd18d0a --- /dev/null +++ b/drivers/nvmem/nvmem-sysfs.c @@ -0,0 +1,230 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2019, Linaro Limited + */ +#include "nvmem.h" + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +static struct lock_class_key eeprom_lock_key; +#endif + +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->priv, 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 -EFBIG; + + 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->priv, 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 = 0644, + }, + .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 = 0444, + }, + .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 = 0600, + }, + .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 = 0400, + }, + .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, +}; + +const struct attribute_group **nvmem_sysfs_get_groups( + struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ + if (config->root_only) + return nvmem->read_only ? + nvmem_ro_root_dev_groups : + nvmem_rw_root_dev_groups; + + return nvmem->read_only ? nvmem_ro_dev_groups : nvmem_rw_dev_groups; +} + +/* + * nvmem_setup_compat() - Create an additional binary entry in + * drivers sys directory, to be backwards compatible with the older + * drivers/misc/eeprom drivers. + */ +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; + + 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; +} + +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); +} diff --git a/drivers/nvmem/nvmem.h b/drivers/nvmem/nvmem.h new file mode 100644 index 000000000000..778f31076121 --- /dev/null +++ b/drivers/nvmem/nvmem.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _DRIVERS_NVMEM_H +#define _DRIVERS_NVMEM_H + +#include +#include +#include +#include +#include +#include + +struct nvmem_device { + const char *name; + struct module *owner; + struct device dev; + int stride; + int word_size; + int id; + struct kref refcnt; + size_t size; + bool read_only; + int flags; + struct bin_attribute eeprom; + struct device *base_dev; + struct list_head cells; + nvmem_reg_read_t reg_read; + nvmem_reg_write_t reg_write; + void *priv; +}; + +#define to_nvmem_device(d) container_of(d, struct nvmem_device, dev) +#define FLAG_COMPAT BIT(0) + +#ifdef CONFIG_NVMEM_SYSFS +const struct attribute_group **nvmem_sysfs_get_groups( + struct nvmem_device *nvmem, + const struct nvmem_config *config); +int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config); +void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config); +#else +static inline const struct attribute_group **nvmem_sysfs_get_groups( + struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ + return NULL; +} + +static inline int nvmem_sysfs_setup_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ + return -ENOSYS; +} +static inline void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem, + const struct nvmem_config *config) +{ +} +#endif /* CONFIG_NVMEM_SYSFS */ + +#endif /* _DRIVERS_NVMEM_H */