diff options
| -rw-r--r-- | drivers/nvmem/core.c | 95 | ||||
| -rw-r--r-- | include/linux/nvmem-consumer.h | 4 |
2 files changed, 99 insertions, 0 deletions
diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c index a5ab1e0c74cf..635e3131eb5f 100644 --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -1606,6 +1606,101 @@ int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val) } EXPORT_SYMBOL_GPL(nvmem_cell_read_u64); +static void *nvmem_cell_read_variable_common(struct device *dev, + const char *cell_id, + size_t max_len, size_t *len) +{ + struct nvmem_cell *cell; + int nbits; + void *buf; + + cell = nvmem_cell_get(dev, cell_id); + if (IS_ERR(cell)) + return cell; + + nbits = cell->nbits; + buf = nvmem_cell_read(cell, len); + nvmem_cell_put(cell); + if (IS_ERR(buf)) + return buf; + + /* + * If nbits is set then nvmem_cell_read() can significantly exaggerate + * the length of the real data. Throw away the extra junk. + */ + if (nbits) + *len = DIV_ROUND_UP(nbits, 8); + + if (*len > max_len) { + kfree(buf); + return ERR_PTR(-ERANGE); + } + + return buf; +} + +/** + * nvmem_cell_read_variable_le_u32() - Read up to 32-bits of data as a little endian number. + * + * @dev: Device that requests the nvmem cell. + * @cell_id: Name of nvmem cell to read. + * @val: pointer to output value. + * + * Return: 0 on success or negative errno. + */ +int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id, + u32 *val) +{ + size_t len; + u8 *buf; + int i; + + buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + /* Copy w/ implicit endian conversion */ + *val = 0; + for (i = 0; i < len; i++) + *val |= buf[i] << (8 * i); + + kfree(buf); + + return 0; +} +EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u32); + +/** + * nvmem_cell_read_variable_le_u64() - Read up to 64-bits of data as a little endian number. + * + * @dev: Device that requests the nvmem cell. + * @cell_id: Name of nvmem cell to read. + * @val: pointer to output value. + * + * Return: 0 on success or negative errno. + */ +int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id, + u64 *val) +{ + size_t len; + u8 *buf; + int i; + + buf = nvmem_cell_read_variable_common(dev, cell_id, sizeof(*val), &len); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + /* Copy w/ implicit endian conversion */ + *val = 0; + for (i = 0; i < len; i++) + *val |= buf[i] << (8 * i); + + kfree(buf); + + return 0; +} +EXPORT_SYMBOL_GPL(nvmem_cell_read_variable_le_u64); + /** * nvmem_device_cell_read() - Read a given nvmem device and cell * diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h index 052293f4cbdb..923dada24eb4 100644 --- a/include/linux/nvmem-consumer.h +++ b/include/linux/nvmem-consumer.h @@ -65,6 +65,10 @@ 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); int nvmem_cell_read_u64(struct device *dev, const char *cell_id, u64 *val); +int nvmem_cell_read_variable_le_u32(struct device *dev, const char *cell_id, + u32 *val); +int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id, + u64 *val); /* direct nvmem device read/write interface */ struct nvmem_device *nvmem_device_get(struct device *dev, const char *name); |