Design and Application of Kernel MTD Layer Data Structure
With the wide application of embedded devices, the requirements for its memory are getting higher and higher. In order to meet this demand, the kernel provides a driver framework suitable for non-volatile memories such as Flash and EEPROM - Memory Technology Device (MTD for short). This article will introduce the data structure design of the MTD layer and its application in the microcontroller.
I. Data structure of MTD layer
The MTD layer provides a series of data structures to describe the physical structure, hardware interface, write protection status and other attributes of the memory. Below we introduce these data structures one by one.
- mtd_info
mtd_info is the most basic data structure in the MTD layer, which describes the physical and logical information of the MTD device, including memory size, block size, page size, and erase area size. It is defined as follows:
struct mtd_info {
struct nvmem_config nvmem_cfg;
char *name;
size_t size;
size_t erasesize;
size_t writesize;
size_t oobsize;
int numeraseregions;
struct mtd_erase_region_info *eraseregions;
uint32_t type;
uint32_t flags;
void *priv;
const struct mtd_ooblayout_ops *ooblayout;
};
The meaning of each field is as follows:
- nvmem_cfg: Used to describe the connection relationship between MTD devices and nvmem devices.
- name: The name of the MTD device.
- size: The total size of the MTD device, in bytes.
- erasesize: The minimum erasable area size of the MTD device, in bytes.
- writesize：M