From 506157be06ba28137b18b7419a4dccfa244f4983 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Fri, 21 Sep 2018 06:40:17 -0700 Subject: [PATCH] nvmem: add support for cell lookups from machine code Add a way for machine code users to associate devices with nvmem cells. This restores the support for non-DT systems but following a different approach. Cells must now be associated with devices using provided routines and data structures before they can be retrieved using nvmem_cell_get(). It's still possible to define cells statically in nvmem_config but cells created this way still need to be associated with consumers using lookup entries. Note that nvmem_find() must be moved higher in the source file as we want to call it from __nvmem_device_get() for devices that don't have a device node. The signature of __nvmem_device_get() is also changed as it's no longer used to retrieve cells. Signed-off-by: Bartosz Golaszewski Signed-off-by: Srinivas Kandagatla Signed-off-by: Greg Kroah-Hartman --- drivers/nvmem/core.c | 129 ++++++++++++++++++++++++++------- include/linux/nvmem-consumer.h | 28 +++++++ 2 files changed, 131 insertions(+), 26 deletions(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index 74b6b97680d5..9cc86d131e1e 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -62,6 +62,9 @@ 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); + #ifdef CONFIG_DEBUG_LOCK_ALLOC static struct lock_class_key eeprom_lock_key; #endif @@ -283,6 +286,18 @@ static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np) return to_nvmem_device(d); } +static struct nvmem_device *nvmem_find(const char *name) +{ + struct device *d; + + d = bus_find_device_by_name(&nvmem_bus_type, NULL, name); + + if (!d) + return NULL; + + return to_nvmem_device(d); +} + static void nvmem_cell_drop(struct nvmem_cell *cell) { mutex_lock(&nvmem_mutex); @@ -472,6 +487,21 @@ nvmem_find_cell_by_index(struct nvmem_device *nvmem, int index) return cell; } +static struct nvmem_cell * +nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id) +{ + struct nvmem_cell *cell = NULL; + + mutex_lock(&nvmem_mutex); + list_for_each_entry(cell, &nvmem->cells, node) { + if (strcmp(cell_id, cell->name) == 0) + break; + } + mutex_unlock(&nvmem_mutex); + + return cell; +} + static int nvmem_add_cells_from_of(struct nvmem_device *nvmem) { struct device_node *parent, *child; @@ -719,16 +749,12 @@ int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem) EXPORT_SYMBOL(devm_nvmem_unregister); static struct nvmem_device *__nvmem_device_get(struct device_node *np, - struct nvmem_cell **cellp, - const char *cell_id) + const char *nvmem_name) { struct nvmem_device *nvmem = NULL; - if (!np) - return ERR_PTR(-ENOENT); - mutex_lock(&nvmem_mutex); - nvmem = of_nvmem_find(np); + nvmem = np ? of_nvmem_find(np) : nvmem_find(nvmem_name); mutex_unlock(&nvmem_mutex); if (!nvmem) return ERR_PTR(-EPROBE_DEFER); @@ -752,18 +778,6 @@ static void __nvmem_device_put(struct nvmem_device *nvmem) kref_put(&nvmem->refcnt, nvmem_device_release); } -static struct nvmem_device *nvmem_find(const char *name) -{ - struct device *d; - - d = bus_find_device_by_name(&nvmem_bus_type, NULL, name); - - if (!d) - return ERR_PTR(-ENOENT); - - return to_nvmem_device(d); -} - #if IS_ENABLED(CONFIG_OF) /** * of_nvmem_device_get() - Get nvmem device from a given id @@ -786,7 +800,7 @@ struct nvmem_device *of_nvmem_device_get(struct device_node *np, const char *id) if (!nvmem_np) return ERR_PTR(-EINVAL); - return __nvmem_device_get(nvmem_np, NULL, NULL); + return __nvmem_device_get(nvmem_np, NULL); } EXPORT_SYMBOL_GPL(of_nvmem_device_get); #endif @@ -890,15 +904,43 @@ struct nvmem_device *devm_nvmem_device_get(struct device *dev, const char *id) } EXPORT_SYMBOL_GPL(devm_nvmem_device_get); -static struct nvmem_cell *nvmem_cell_get_from_list(const char *cell_id) +static struct nvmem_cell * +nvmem_cell_get_from_lookup(struct device *dev, const char *con_id) { - struct nvmem_cell *cell = NULL; + struct nvmem_cell *cell = ERR_PTR(-ENOENT); + struct nvmem_cell_lookup *lookup; struct nvmem_device *nvmem; + const char *dev_id; - nvmem = __nvmem_device_get(NULL, &cell, cell_id); - if (IS_ERR(nvmem)) - return ERR_CAST(nvmem); + 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(NULL, lookup->nvmem_name); + if (!nvmem) { + /* Provider may not be registered yet. */ + cell = ERR_PTR(-EPROBE_DEFER); + goto out; + } + + cell = nvmem_find_cell_by_name(nvmem, + lookup->cell_name); + if (!cell) { + __nvmem_device_put(nvmem); + goto out; + } + } + } + +out: + mutex_unlock(&nvmem_lookup_mutex); return cell; } @@ -935,7 +977,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, if (!nvmem_np) return ERR_PTR(-EINVAL); - nvmem = __nvmem_device_get(nvmem_np, NULL, NULL); + nvmem = __nvmem_device_get(nvmem_np, NULL); of_node_put(nvmem_np); if (IS_ERR(nvmem)) return ERR_CAST(nvmem); @@ -975,7 +1017,7 @@ struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id) if (!cell_id) return ERR_PTR(-EINVAL); - return nvmem_cell_get_from_list(cell_id); + return nvmem_cell_get_from_lookup(dev, cell_id); } EXPORT_SYMBOL_GPL(nvmem_cell_get); @@ -1405,6 +1447,41 @@ void nvmem_del_cell_table(struct nvmem_cell_table *table) } 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. * diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h index 0389fe00b177..27eee3945405 100644 --- a/include/linux/nvmem-consumer.h +++ b/include/linux/nvmem-consumer.h @@ -29,6 +29,24 @@ struct nvmem_cell_info { unsigned int nbits; }; +/** + * struct nvmem_cell_lookup - cell lookup entry + * + * @nvmem_name: Name of the provider. + * @cell_name: Name of the nvmem cell as defined in the name field of + * struct nvmem_cell_info. + * @dev_id: Name of the consumer device that will be associated with + * this cell. + * @con_id: Connector id for this cell lookup. + */ +struct nvmem_cell_lookup { + const char *nvmem_name; + const char *cell_name; + const char *dev_id; + const char *con_id; + struct list_head node; +}; + #if IS_ENABLED(CONFIG_NVMEM) /* Cell based interface */ @@ -57,6 +75,11 @@ int nvmem_device_cell_write(struct nvmem_device *nvmem, const char *nvmem_dev_name(struct nvmem_device *nvmem); +void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, + size_t nentries); +void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, + size_t nentries); + #else static inline struct nvmem_cell *nvmem_cell_get(struct device *dev, @@ -151,6 +174,11 @@ static inline const char *nvmem_dev_name(struct nvmem_device *nvmem) return NULL; } +static inline void +nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) {} +static inline void +nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) {} + #endif /* CONFIG_NVMEM */ #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)