diff options
| -rw-r--r-- | Documentation/driver-api/nvmem.rst | 15 | ||||
| -rw-r--r-- | drivers/nvmem/Kconfig | 4 | ||||
| -rw-r--r-- | drivers/nvmem/Makefile | 1 | ||||
| -rw-r--r-- | drivers/nvmem/core.c | 120 | ||||
| -rw-r--r-- | drivers/nvmem/layouts/Kconfig | 5 | ||||
| -rw-r--r-- | drivers/nvmem/layouts/Makefile | 4 | ||||
| -rw-r--r-- | include/linux/nvmem-consumer.h | 7 | ||||
| -rw-r--r-- | include/linux/nvmem-provider.h | 51 |
8 files changed, 207 insertions, 0 deletions
diff --git a/Documentation/driver-api/nvmem.rst b/Documentation/driver-api/nvmem.rst index e3366322d46c..de221e91c8e3 100644 --- a/Documentation/driver-api/nvmem.rst +++ b/Documentation/driver-api/nvmem.rst @@ -185,3 +185,18 @@ ex:: ===================== See Documentation/devicetree/bindings/nvmem/nvmem.txt + +8. NVMEM layouts +================ + +NVMEM layouts are yet another mechanism to create cells. With the device +tree binding it is possible to specify simple cells by using an offset +and a length. Sometimes, the cells doesn't have a static offset, but +the content is still well defined, e.g. tag-length-values. In this case, +the NVMEM device content has to be first parsed and the cells need to +be added accordingly. Layouts let you read the content of the NVMEM device +and let you add cells dynamically. + +Another use case for layouts is the post processing of cells. With layouts, +it is possible to associate a custom post processing hook to a cell. It +even possible to add this hook to cells not created by the layout itself. diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig index 3b3832f4dfad..a2afba11c890 100644 --- a/drivers/nvmem/Kconfig +++ b/drivers/nvmem/Kconfig @@ -21,6 +21,10 @@ config NVMEM_SYSFS This interface is mostly used by userspace applications to read/write directly into nvmem. +# Layouts + +source "drivers/nvmem/layouts/Kconfig" + # Devices config NVMEM_APPLE_EFUSES diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile index 6a1efffa88f0..f82431ec8aef 100644 --- a/drivers/nvmem/Makefile +++ b/drivers/nvmem/Makefile @@ -5,6 +5,7 @@ obj-$(CONFIG_NVMEM) += nvmem_core.o nvmem_core-y := core.o +obj-y += layouts/ # Devices obj-$(CONFIG_NVMEM_APPLE_EFUSES) += nvmem-apple-efuses.o diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 22024b830788..b9be1faeb7be 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -40,6 +40,7 @@ struct nvmem_device { nvmem_reg_write_t reg_write; nvmem_cell_post_process_t cell_post_process; struct gpio_desc *wp_gpio; + struct nvmem_layout *layout; void *priv; }; @@ -74,6 +75,9 @@ static LIST_HEAD(nvmem_lookup_list); static BLOCKING_NOTIFIER_HEAD(nvmem_notifier); +static DEFINE_SPINLOCK(nvmem_layout_lock); +static LIST_HEAD(nvmem_layouts); + static int __nvmem_reg_read(struct nvmem_device *nvmem, unsigned int offset, void *val, size_t bytes) { @@ -728,6 +732,101 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem) return 0; } +int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner) +{ + layout->owner = owner; + + spin_lock(&nvmem_layout_lock); + list_add(&layout->node, &nvmem_layouts); + spin_unlock(&nvmem_layout_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(__nvmem_layout_register); + +void nvmem_layout_unregister(struct nvmem_layout *layout) +{ + spin_lock(&nvmem_layout_lock); + list_del(&layout->node); + spin_unlock(&nvmem_layout_lock); +} +EXPORT_SYMBOL_GPL(nvmem_layout_unregister); + +static struct nvmem_layout *nvmem_layout_get(struct nvmem_device *nvmem) +{ + struct device_node *layout_np, *np = nvmem->dev.of_node; + struct nvmem_layout *l, *layout = NULL; + + layout_np = of_get_child_by_name(np, "nvmem-layout"); + if (!layout_np) + return NULL; + + spin_lock(&nvmem_layout_lock); + + list_for_each_entry(l, &nvmem_layouts, node) { + if (of_match_node(l->of_match_table, layout_np)) { + if (try_module_get(l->owner)) + layout = l; + + break; + } + } + + spin_unlock(&nvmem_layout_lock); + of_node_put(layout_np); + + return layout; +} + +static void nvmem_layout_put(struct nvmem_layout *layout) +{ + if (layout) + module_put(layout->owner); +} + +static int nvmem_add_cells_from_layout(struct nvmem_device *nvmem) +{ + struct nvmem_layout *layout = nvmem->layout; + int ret; + + if (layout && layout->add_cells) { + ret = layout->add_cells(&nvmem->dev, nvmem, layout); + if (ret) + return ret; + } + + return 0; +} + +#if IS_ENABLED(CONFIG_OF) +/** + * of_nvmem_layout_get_container() - Get OF node to layout container. + * + * @nvmem: nvmem device. + * + * Return: a node pointer with refcount incremented or NULL if no + * container exists. Use of_node_put() on it when done. + */ +struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem) +{ + return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout"); +} +EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container); +#endif + +const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem, + struct nvmem_layout *layout) +{ + struct device_node __maybe_unused *layout_np; + const struct of_device_id *match; + + layout_np = of_nvmem_layout_get_container(nvmem); + match = of_match_node(layout->of_match_table, layout_np); + + return match ? match->data : NULL; +} +EXPORT_SYMBOL_GPL(nvmem_layout_get_match_data); + /** * nvmem_register() - Register a nvmem device for given nvmem_config. * Also creates a binary entry in /sys/bus/nvmem/devices/dev-name/nvmem @@ -834,6 +933,12 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) goto err_put_device; } + /* + * If the driver supplied a layout by config->layout, the module + * pointer will be NULL and nvmem_layout_put() will be a noop. + */ + nvmem->layout = config->layout ?: nvmem_layout_get(nvmem); + if (config->cells) { rval = nvmem_add_cells(nvmem, config->cells, config->ncells); if (rval) @@ -854,12 +959,17 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config) if (rval) goto err_remove_cells; + rval = nvmem_add_cells_from_layout(nvmem); + 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); + nvmem_layout_put(nvmem->layout); if (config->compat) nvmem_sysfs_remove_compat(nvmem, config); err_put_device: @@ -881,6 +991,7 @@ static void nvmem_device_release(struct kref *kref) device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom); nvmem_device_remove_all_cells(nvmem); + nvmem_layout_put(nvmem->layout); device_unregister(&nvmem->dev); } @@ -1246,6 +1357,15 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id) return ERR_PTR(-EINVAL); } + /* nvmem layouts produce cells within the nvmem-layout container */ + if (of_node_name_eq(nvmem_np, "nvmem-layout")) { + nvmem_np = of_get_next_parent(nvmem_np); + if (!nvmem_np) { + of_node_put(cell_np); + return ERR_PTR(-EINVAL); + } + } + nvmem = __nvmem_device_get(nvmem_np, device_match_of_node); of_node_put(nvmem_np); if (IS_ERR(nvmem)) { diff --git a/drivers/nvmem/layouts/Kconfig b/drivers/nvmem/layouts/Kconfig new file mode 100644 index 000000000000..9ad3911d1605 --- /dev/null +++ b/drivers/nvmem/layouts/Kconfig @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 + +menu "Layout Types" + +endmenu diff --git a/drivers/nvmem/layouts/Makefile b/drivers/nvmem/layouts/Makefile new file mode 100644 index 000000000000..6fdb3c60a4fa --- /dev/null +++ b/drivers/nvmem/layouts/Makefile @@ -0,0 +1,4 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for nvmem layouts. +# diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h index 1f62f7ba71ca..fa030d93b768 100644 --- a/include/linux/nvmem-consumer.h +++ b/include/linux/nvmem-consumer.h @@ -239,6 +239,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id); struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *name); +struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem); #else static inline struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, const char *id) @@ -251,6 +252,12 @@ static inline struct nvmem_device *of_nvmem_device_get(struct device_node *np, { return ERR_PTR(-EOPNOTSUPP); } + +static inline struct device_node * +of_nvmem_layout_get_container(struct nvmem_device *nvmem) +{ + return ERR_PTR(-EOPNOTSUPP); +} #endif /* CONFIG_NVMEM && CONFIG_OF */ #endif /* ifndef _LINUX_NVMEM_CONSUMER_H */ diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h index 0262b86194eb..535c5f9f3309 100644 --- a/include/linux/nvmem-provider.h +++ b/include/linux/nvmem-provider.h @@ -88,6 +88,7 @@ struct nvmem_cell_info { * @stride: Minimum read/write access stride. * @priv: User context passed to read/write callbacks. * @ignore_wp: Write Protect pin is managed by the provider. + * @layout: Fixed layout associated with this nvmem device. * * Note: A default "nvmem<id>" name will be assigned to the device if * no name is specified in its configuration. In such case "<id>" is @@ -109,6 +110,7 @@ struct nvmem_config { bool read_only; bool root_only; bool ignore_wp; + struct nvmem_layout *layout; struct device_node *of_node; bool no_of_node; nvmem_reg_read_t reg_read; @@ -142,6 +144,33 @@ struct nvmem_cell_table { struct list_head node; }; +/** + * struct nvmem_layout - NVMEM layout definitions + * + * @name: Layout name. + * @of_match_table: Open firmware match table. + * @add_cells: Will be called if a nvmem device is found which + * has this layout. The function will add layout + * specific cells with nvmem_add_one_cell(). + * @owner: Pointer to struct module. + * @node: List node. + * + * A nvmem device can hold a well defined structure which can just be + * evaluated during runtime. For example a TLV list, or a list of "name=val" + * pairs. A nvmem layout can parse the nvmem device and add appropriate + * cells. + */ +struct nvmem_layout { + const char *name; + const struct of_device_id *of_match_table; + int (*add_cells)(struct device *dev, struct nvmem_device *nvmem, + struct nvmem_layout *layout); + + /* private */ + struct module *owner; + struct list_head node; +}; + #if IS_ENABLED(CONFIG_NVMEM) struct nvmem_device *nvmem_register(const struct nvmem_config *cfg); @@ -156,6 +185,14 @@ void nvmem_del_cell_table(struct nvmem_cell_table *table); int nvmem_add_one_cell(struct nvmem_device *nvmem, const struct nvmem_cell_info *info); +int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner); +#define nvmem_layout_register(layout) \ + __nvmem_layout_register(layout, THIS_MODULE) +void nvmem_layout_unregister(struct nvmem_layout *layout); + +const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem, + struct nvmem_layout *layout); + #else static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c) @@ -179,5 +216,19 @@ static inline int nvmem_add_one_cell(struct nvmem_device *nvmem, return -EOPNOTSUPP; } +static inline int nvmem_layout_register(struct nvmem_layout *layout) +{ + return -EOPNOTSUPP; +} + +static inline void nvmem_layout_unregister(struct nvmem_layout *layout) {} + +static inline const void * +nvmem_layout_get_match_data(struct nvmem_device *nvmem, + struct nvmem_layout *layout) +{ + return NULL; +} + #endif /* CONFIG_NVMEM */ #endif /* ifndef _LINUX_NVMEM_PROVIDER_H */ |