@@ -1828,6 +1828,35 @@ int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len)
EXPORT_SYMBOL_GPL(nvmem_cell_write);
+/**
+ * nvmem_cell_get_size() - Retrieve the storage size of an NVMEM cell.
+ * @cell: Pointer to the NVMEM cell structure.
+ * @bytes: Optional pointer to store the cell size in bytes (can be NULL).
+ * @bits: Optional pointer to store the cell size in bits (can be NULL).
+ *
+ * This function allows consumers to retrieve the size of a specific NVMEM
+ * cell before performing read/write operations. It is useful for validating
+ * buffer sizes to prevent mismatched writes.
+ *
+ * Return: 0 on success or negative on failure.
+ */
+int nvmem_cell_get_size(struct nvmem_cell *cell, size_t *bytes, size_t *bits)
+{
+ struct nvmem_cell_entry *entry = cell->entry;
+
+ if (!entry->nvmem)
+ return -EINVAL;
+
+ if (bytes)
+ *bytes = entry->bytes;
+
+ if (bits)
+ *bits = entry->nbits;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nvmem_cell_get_size);
+
static int nvmem_cell_read_common(struct device *dev, const char *cell_id,
void *val, size_t count)
{
@@ -56,6 +56,7 @@ void nvmem_cell_put(struct nvmem_cell *cell);
void devm_nvmem_cell_put(struct device *dev, struct nvmem_cell *cell);
void *nvmem_cell_read(struct nvmem_cell *cell, size_t *len);
int nvmem_cell_write(struct nvmem_cell *cell, void *buf, size_t len);
+int nvmem_cell_get_size(struct nvmem_cell *cell, size_t *bytes, size_t *bits);
int nvmem_cell_read_u8(struct device *dev, const char *cell_id, u8 *val);
int nvmem_cell_read_u16(struct device *dev, const char *cell_id, u16 *val);
int nvmem_cell_read_u32(struct device *dev, const char *cell_id, u32 *val);
@@ -128,6 +129,12 @@ static inline int nvmem_cell_write(struct nvmem_cell *cell,
return -EOPNOTSUPP;
}
+static inline int nvmem_cell_get_size(struct nvmem_cell *cell, size_t *bytes,
+ size_t *bits)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int nvmem_cell_read_u8(struct device *dev,
const char *cell_id, u8 *val)
{
Add nvmem_cell_get_size() function to provide access to cell size metrics. In some cases we may get cell size less as consumer would expect it. So, nvmem_cell_write() would fail with incorrect buffer size. Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> --- changes v6: - update function comment for nvmem_cell_get_size() --- drivers/nvmem/core.c | 29 +++++++++++++++++++++++++++++ include/linux/nvmem-consumer.h | 7 +++++++ 2 files changed, 36 insertions(+)