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Subject[PATCH v4 13/22] nvmem: add support for cell info
Date
From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Add new structs and routines allowing users to define nvmem cells from
machine code. This global list of entries is parsed when a provider
is registered and cells are associated with the relevant nvmem_device
struct.

A possible improvement for the future is to allow users to register
cell tables after the nvmem provider has been registered by updating
the cell list at each call to nvmem_(add|del)_cell_table().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
drivers/nvmem/core.c | 72 ++++++++++++++++++++++++++++++++++
include/linux/nvmem-provider.h | 33 +++++++++++-----
2 files changed, 96 insertions(+), 9 deletions(-)

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index 585688ea2152..9329857f6137 100644
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -59,6 +59,9 @@ struct nvmem_cell {
static DEFINE_MUTEX(nvmem_mutex);
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
@@ -416,6 +419,43 @@ static int nvmem_setup_compat(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
@@ -502,8 +542,14 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
goto err_teardown_compat;
}

+ rval = nvmem_add_cells_from_table(nvmem);
+ if (rval)
+ goto err_remove_cells;
+
return nvmem;

+err_remove_cells:
+ nvmem_device_remove_all_cells(nvmem);
err_teardown_compat:
if (config->compat)
device_remove_bin_file(nvmem->base_dev, &nvmem->eeprom);
@@ -1306,6 +1352,32 @@ int nvmem_device_write(struct nvmem_device *nvmem,
}
EXPORT_SYMBOL_GPL(nvmem_device_write);

+/**
+ * nvmem_add_cell_table() - register a table of cell info entries
+ *
+ * @table: table of cell info entries
+ */
+void nvmem_add_cell_table(struct nvmem_cell_table *table)
+{
+ mutex_lock(&nvmem_cell_mutex);
+ list_add_tail(&table->node, &nvmem_cell_tables);
+ mutex_unlock(&nvmem_cell_mutex);
+}
+EXPORT_SYMBOL_GPL(nvmem_add_cell_table);
+
+/**
+ * nvmem_del_cell_table() - remove a previously registered cell info table
+ *
+ * @table: table of cell info entries
+ */
+void nvmem_del_cell_table(struct nvmem_cell_table *table)
+{
+ mutex_lock(&nvmem_cell_mutex);
+ list_del(&table->node);
+ mutex_unlock(&nvmem_cell_mutex);
+}
+EXPORT_SYMBOL_GPL(nvmem_del_cell_table);
+
/**
* nvmem_dev_name() - Get the name of a given nvmem device.
*
diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 0f357d0c1e75..5c9f205cac8f 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -67,6 +67,25 @@ struct nvmem_config {
struct device *base_dev;
};

+/**
+ * struct nvmem_cell_table - NVMEM cell definitions for given provider
+ *
+ * @nvmem_name: Provider name.
+ * @cells: Array of cell definitions.
+ * @ncells: Number of cell definitions in the array.
+ * @node: List node.
+ *
+ * This structure together with related helper functions is provided for users
+ * that don't can't access the nvmem provided structure but wish to register
+ * cell definitions for it e.g. board files registering an EEPROM device.
+ */
+struct nvmem_cell_table {
+ const char *nvmem_name;
+ const struct nvmem_cell_info *cells;
+ size_t ncells;
+ struct list_head node;
+};
+
#if IS_ENABLED(CONFIG_NVMEM)

struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
@@ -77,9 +96,9 @@ struct nvmem_device *devm_nvmem_register(struct device *dev,

int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem);

-int nvmem_add_cells(struct nvmem_device *nvmem,
- const struct nvmem_cell_info *info,
- int ncells);
+void nvmem_add_cell_table(struct nvmem_cell_table *table);
+void nvmem_del_cell_table(struct nvmem_cell_table *table);
+
#else

static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
@@ -102,12 +121,8 @@ devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)

}

-static inline int nvmem_add_cells(struct nvmem_device *nvmem,
- const struct nvmem_cell_info *info,
- int ncells)
-{
- return -ENOSYS;
-}
+static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
+static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}

#endif /* CONFIG_NVMEM */
#endif /* ifndef _LINUX_NVMEM_PROVIDER_H */
--
2.18.0
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