From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> Add a way for machine code users to associate devices with nvmem cells. Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> --- drivers/nvmem/core.c | 142 +++++++++++++++++++++++++++------- include/linux/nvmem-machine.h | 15 ++++ 2 files changed, 130 insertions(+), 27 deletions(-) diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index da7a9d5beb33..d7c609109cfd 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); + static BLOCKING_NOTIFIER_HEAD(nvmem_notifier); #ifdef CONFIG_DEBUG_LOCK_ALLOC @@ -285,6 +288,18 @@ 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); @@ -421,6 +436,21 @@ 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; @@ -691,22 +721,16 @@ 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) +static struct nvmem_device * +__nvmem_device_get(struct device_node *np, const char *name) { struct nvmem_device *nvmem = NULL; - if (!np) - return ERR_PTR(-EINVAL); - mutex_lock(&nvmem_mutex); - - nvmem = of_nvmem_find(np); - if (!nvmem) { - mutex_unlock(&nvmem_mutex); - return ERR_PTR(-EPROBE_DEFER); - } - + nvmem = np ? of_nvmem_find(np) : nvmem_find(name); mutex_unlock(&nvmem_mutex); + if (!nvmem) + return ERR_PTR(-EPROBE_DEFER); if (!try_module_get(nvmem->owner)) { dev_err(&nvmem->dev, @@ -726,18 +750,6 @@ 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 NULL; - - return to_nvmem_device(d); -} - #if IS_ENABLED(CONFIG_OF) /** * of_nvmem_device_get() - Get nvmem device from a given id @@ -760,7 +772,7 @@ 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); + return __nvmem_device_get(nvmem_np, NULL); } EXPORT_SYMBOL_GPL(of_nvmem_device_get); #endif @@ -897,7 +909,7 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, if (!nvmem_np) return ERR_PTR(-EINVAL); - nvmem = __nvmem_device_get(nvmem_np); + nvmem = __nvmem_device_get(nvmem_np, NULL); of_node_put(nvmem_np); if (IS_ERR(nvmem)) return ERR_CAST(nvmem); @@ -913,6 +925,43 @@ struct nvmem_cell *of_nvmem_cell_get(struct device_node *np, EXPORT_SYMBOL_GPL(of_nvmem_cell_get); #endif +static struct nvmem_cell * +nvmem_cell_get_from_lookup(struct device *dev, const char *cell_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->cell_id, cell_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, cell_id); + if (!cell) + goto out; + } + } + +out: + mutex_unlock(&nvmem_lookup_mutex); + return cell; +} + /** * nvmem_cell_get() - Get nvmem cell of device form a given cell name * @@ -925,10 +974,14 @@ EXPORT_SYMBOL_GPL(of_nvmem_cell_get); */ struct nvmem_cell *nvmem_cell_get(struct device *dev, const char *cell_id) { - if (!dev->of_node) + if (dev->of_node) + return of_nvmem_cell_get(dev->of_node, cell_id); + + /* Only allow empty cell_id for DT systems. */ + if (!cell_id) return ERR_PTR(-EINVAL); - return of_nvmem_cell_get(dev->of_node, cell_id); + return nvmem_cell_get_from_lookup(dev, cell_id); } EXPORT_SYMBOL_GPL(nvmem_cell_get); @@ -1300,6 +1353,41 @@ 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-machine.h b/include/linux/nvmem-machine.h index 1e199dfaacab..79421bbf9d13 100644 --- a/include/linux/nvmem-machine.h +++ b/include/linux/nvmem-machine.h @@ -26,16 +26,31 @@ struct nvmem_cell_table { struct list_head node; }; +struct nvmem_cell_lookup { + const char *nvmem_name; + const char *dev_id; + const char *cell_id; + struct list_head node; +}; + #if IS_ENABLED(CONFIG_NVMEM) void nvmem_add_cell_table(struct nvmem_cell_table *table); void nvmem_del_cell_table(struct nvmem_cell_table *table); +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 /* CONFIG_NVMEM */ static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {} static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {} +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 */ #endif /* ifndef _LINUX_NVMEM_MACHINE_H */ -- 2.18.0