WO2009103181A1

WO2009103181A1 - Device for implementing file system on nandflash of mobile terminal

Info

Publication number: WO2009103181A1
Application number: PCT/CN2008/000361
Authority: WO
Inventors: 王志慧; 谢仁艿; 徐金禄; 段红乐; 张欣; 赵瑞
Original assignee: 中兴通讯股份有限公司
Priority date: 2008-02-18
Filing date: 2008-02-18
Publication date: 2009-08-27
Also published as: CN101809546A

Abstract

A device for implementing the file system on the NANDFLASH of the mobile terminal is provided. The device includes a FAT file system, and also includes a file system transmission unit set between the FAT file system and the NANDFLASH for garbage collection, invalid block management and address mapping to the NANDFLASH. Thereby, the defect that FAT file system can not be directly used on the NANDFLASH will be solved.

Description

TECHNICAL FIELD The present invention relates to the field of mobile terminal technologies, and in particular, to a method for implementing a file system on a non-linear flash memory (NANDFLASH). BACKGROUND With the rapid development of the modern information society, NANDFLASH is a storage medium, and its advantages such as large capacity and low cost are increasingly favored by many terminal devices. Due to the special nature of NANDFLASH, bad block management, address mapping, garbage collection, etc., 4 megabytes of warfare is proposed for traditional file systems. Traditional file systems (for example: FAT file system) do not have bad block management and addresses for NANDFLASH. The processing mechanism of mapping and garbage collection, therefore, cannot directly manage NANDFLASH. The present invention proposes an improvement in the use of the FAT file system on NAND FLASH. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is a primary object of the present invention to provide an apparatus for implementing a file system on a non-linear flash memory of a mobile terminal, including a FAT file system, characterized in that it further includes : File System Transfer Unit, set between the FAT file system and non-linear flash for garbage collection, bad block management, and address mapping for non-linear flash. The device according to the present invention may further include: an initialization module, configured to acquire related parameter information of the non-linear flash memory, and obtain state information and address mapping information of each block in the management area by scanning the management area of the entire file system to be in the memory A block state mapping table and a block address mapping table are formed. The relevant parameter information includes the page size, the block size, and the size of the management area of the file system. The apparatus according to the present invention may further comprise a garbage collection module for performing the following steps when there is data to be updated on the non-linear flash memory: obtaining the physical address of the data block to be updated by the address mapping table, and passing the file system The transmission unit reads the data to be updated into the memory; performs data update in the memory, and writes the updated data to the new physical address through the file system transmission unit; And erasing the data block to be updated, and updating the state mapping table and the block address mapping table. Bad block management package ^ "bad block detection and bad block flag. The apparatus according to the present invention may further comprise: a bad block detection module for causing the file system transmission unit to scan the management area of the entire file system during initialization, by checking each The bad block flag of the redundant area of the first page and the second page of the block determines whether the block is a bad block. If the block is a bad block, the block is recorded as a bad block in the block state mapping table, if the block is not a bad block The block is then recorded as a valid block in the block state mapping table. The apparatus according to the present invention may further include: a bad block flag module, configured to cause the file system transfer unit to write to the non-linear flash memory through the file system transfer unit, Determining whether the write operation is successful, if the write operation is successful, marking the bad block flag bit in the redundant area of the first page and the second page of the block in the non-linear flash memory as the used state, if the write operation fails The bad block flag is marked as a bad block, and then the block address mapping table is updated. The file system transfer unit receives the logic when it performs the read operation and the write operation. The address is converted to a physical address. The apparatus according to the present invention may further comprise a write module for performing the following steps when performing a write operation: buffering the data to be written in the file system transfer unit, when the write data reaches a logic In the block, the valid block is searched in the state mapping table, and the address in the address mapping table is mapped to the physical block address according to the address of the logical block; the data to be written is cyclically written to the physical block of the non-linear flash memory, and the last block of the physical block Recording the state and the address of the physical block in the redundant area of the page; and updating the state mapping table and the block address mapping table in the memory. The apparatus according to the present invention may further include a reading module for performing the reading operation The following steps: mapping the physical block address of the read page by the block address mapping table, searching the physical page address by the physical block address; and reading the data of the read page from the non-linear flash memory according to the physical page address. Technical solution, FAT file system to the next (FTL) is to initialize, read, write interface, read and write is a logical page, The FTL layer is converted into an actual physical address, and operations such as garbage collection, bad block management, address mapping, etc. are completed during the reading and writing process, and finally the function of storing the file on the NAND FLASH is realized. Other features and advantages of the present invention will follow Explained in the instructions, and, in part, from It will become apparent in the specification or may be understood by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the <RTI The drawings are intended to provide a further understanding of the invention, and are intended to be a part of the description of the invention. In the drawings: FIG. 1 is a block diagram showing an apparatus for implementing a file system on a non-linear flash memory of a mobile terminal of the present invention; FIG. 2 is a diagram showing a file system for a NAND FLASH according to an embodiment of the present invention. Figure 3 is a flow chart showing the initialization of the FTL in the file system according to an embodiment of the present invention; Figure 4 is a flow chart showing the garbage collection according to the embodiment of the present invention; Figure 5 and Figure 6 shows a flow chart of bad block management according to an embodiment of the present invention; and FIG. 7 shows a flow chart of address mapping according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention are described with reference to the accompanying drawings. 1 shows a block diagram of an apparatus for implementing a file system on a non-linear flash memory of a mobile terminal in accordance with the present invention. Referring to FIG. 1, there is provided an apparatus for implementing a file system on a non-linear flash memory of a mobile terminal, comprising a FAT file system 101, further comprising: a file system transmission unit 102, disposed in the FAT file system 101 and non-linear Between the flash memories 103, it is used for garbage collection, bad block management, and address mapping of the non-linear flash memory 103. The device according to the present invention may further include: an initialization module, configured to acquire related parameter information of the non-linear flash memory, and obtain state information and address mapping information of each block in the management area by performing a management area of the entire file system, to A block state mapping table and a block address mapping table are formed in the memory. The relevant parameter information includes the page size, the block size, and the size of the management area of the file system. The apparatus of the present invention may further comprise a garbage collection module for performing the following steps when there is data to be updated on the non-linear flash memory: obtaining a physical address of the data block to be updated by the address mapping table, and transmitting the unit through the file system Reading the data to be updated into the memory; updating the data in the memory and writing the updated data to the new physical address through the file system transfer unit; and erasing the data block to be updated, and updating the status map And block address mapping table. Bad block management includes bad block detection and bad block flags. The apparatus according to the present invention may further include: a bad block detecting module, configured to cause the file system transfer unit to scan a management area of the entire file system during initialization, by checking a redundant area of the first page and the second page of each block The bad block flag bit determines whether the block is a bad block. If the block is a bad block, the block is recorded as a bad block in the block state mapping table, and if the block is not a bad block, the block is recorded as a valid block in the block state mapping table. The device of the present invention may further include: a bad block flag module, configured to enable the file system transmission unit to determine whether the write operation is successful when writing to the non-linear flash memory through the file system transfer unit, and if the write operation is successful, the non-linearity The bad block flag bit in the redundant area of the first page and the second page of the block in the flash memory is marked as used, and if the write operation fails, the bad block flag is marked as a bad block, and then the block is updated. Address mapping table. The file system transfer unit converts the logical address it receives into a physical address when performing read operations and write operations. The apparatus according to the present invention may further comprise a write module for performing the following steps when performing a write operation: buffering data to be written in the file system transfer unit, when the write data reaches a logical block, in the state map Finding a valid block in the table, mapping to the physical block address according to the address of the logical block in the address mapping table; writing the data to be written to the physical block of the non-linear flash memory, in the redundant area of the last page of the physical block Record the state and logical address of the physical block; and update the state map and block address map in memory. The apparatus according to the invention may further comprise a reading module for performing the following steps when performing the reading operation: mapping ^ by the block address mapping table! The physical block address of the page is read, the physical page address is searched for by the physical block address, and the data of the page to be read is read from the non-linear flash memory by the physical page address. 2 is a flow chart showing an implementation method for a file system on a NAND FLASH in accordance with an embodiment of the present invention. As shown in FIG. 2, the method includes the following steps:

S202. The FAT file system mainly organizes and manages files according to the FAT format, and presents them to the FTL layer in the form of logical sectors. S204. FTL mainly performs logical address to physical address conversion, garbage collection, and bad block management.

S206. NANDFLASH flash memory, physical storage of files through the driver layer interface. Figure 3-7 below shows the implementation mechanism of the FTL layer. Figure 3 is a flow chart showing the initialization of an FTL in a file system in accordance with an embodiment of the present invention. As shown in Figure 3, the method package ^" the following steps:

S302. Obtain NANDFLASH related parameter information, page size, block size, and file system management area size.

S304. Obtaining the state information and the address mapping information of each block by scanning the management area of the entire file system, and forming a block state mapping table and a block address mapping table in the memory. 4 shows a flow chart of garbage collection in accordance with an embodiment of the present invention. As shown in Figure 4, the method packs the following steps:

S402, when there is data on the NANDFLASH to be updated, the update is performed according to the block, and the updated data needs to be written on a new physical block, and the available physics is obtained through the state mapping table and the address mapping table in FIG. Block address. S404, through the address mapping table in the memory, find the physical address of the old data block that needs to be updated, and call the NANDFLASH driver layer interface to read the data into the memory.

S406: Update the data in the memory, and cover the data block that needs to be updated with the new data block.

S408, by calling the NANDFLASH driver layer interface, the updated data of 4 bar is written to the new physical block.

S410, the updated data block becomes a garbage block on the NANDFLASH, and the driver is driven to block 4 bar garbage block erasure. S412. Update the block state mapping table and the block address mapping table in the memory. Through the above steps, it can be seen that: garbage collection is mainly to recover those old invalid data blocks when there is data to be updated on NANDFLASH. 4 is a flow chart of bad block management in accordance with the present invention. Bad block management mainly includes bad block detection and bad block flags. As shown in Figure 5, bad block detection includes the following steps:

S502. Bad block detection is performed at the time of file system initialization, scanning all blocks of NANDFLASH, and performing bad block check.

S504. Determine whether the block is a bad block by using the bad block flag of the first page and the second page redundant area of each block.

S506. If this block is a bad block, the block of 4 bar in the in-memory block state mapping table is an invalid block.

S508. If the block is a normal block, the block of 4 bar in the in-memory block state mapping table is a valid block. As shown in Figure 6, the bad block flag includes the following steps:

S602. When writing data to NANDFLASH, find the available physical block address through the memory map.

S604. Call the driver layer interface to perform NANDFLASH write operation.

S606. Determine whether the writing is successful. S608. If it fails, the redundant areas of the first page and the second page of the block on the NANDFLASH are marked as bad blocks.

S510. Update the mapping table in the memory and mark this block as a bad block state.

S512. If successful, update the mapping table in memory and mark this block as used. When the address mapping is to read and write to NANDFLASH, the upper layer is transferred to the FTL as a logical address, which is converted into a physical address by the FTL layer. As shown in FIG. 7, the method includes the following steps: S702. The FAT file system organizes information about the file, calls the FTL layer interface, reads and writes the file, and reads and writes the logical address of the page.

S704. If it is a write operation, the data information of the file is cached in the FTL layer.

S706. When the buffered data is a continuous logical page, the entire block of data is written to the NANDFLASH physical medium.

S708. Find the valid blocks that have not been used in the state mapping table. In the address mapping table, map to the actual physical block address according to the logical block address.

S710. The data is cyclically written to the physical block of NANDFLASH, and the status and logical address of the block are recorded in the redundant area of the last page in the block. S712. Update the status information and the address information of the block in the memory.

S714. The FTL interface layer performs a read operation, and maps to the physical block address where the page is located through the address mapping table, and finds the physical page address through the physical block address.

S716. 4 bar data is read from NANDFLASH and returned to the upper layer. Through the above several parts, the file system for NANDFLASH is realized. This invention solves the drawback that the FAT file system cannot be directly used in NANDFLASH. In the implementation of the FTL layer:

1 Establish a mapping table in the memory, with the state and address of the block as the mapping relationship, which greatly improves the search speed of the physical address;

2 File data is first cached in memory. When reading and writing files, it is first searched in memory, which improves the speed of reading and writing files;

3 Data update according to the block reduces the number of physical reads and writes to NANDFLASH, thereby increasing the service life of NANDFLASH. The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

An apparatus for implementing a file system on a non-linear flash memory of a mobile terminal, comprising a FAT file system, further comprising:

a file system transmission unit disposed between the FAT file system and the non-linear flash memory for garbage collection, bad block management, and address mapping of the non-linear flash memory.

2. The device according to claim 1, further comprising:

An initialization module, configured to acquire related parameter information of the non-linear flash memory, and obtain status information and address mapping information of each block in the management area by scanning a management area of the entire file system to form a block in the memory State map and block address map.

3. The apparatus according to claim 2, wherein the related parameter information comprises a page size, a block size, and a size of a management area of the file system.

4. The apparatus according to claim 3, further comprising a garbage collection module, configured to perform the following steps when there is data to be updated on the non-linear flash memory:

Obtaining, by the address mapping table, a physical address of the data block to be updated, and reading, by the file system transmission unit, the data to be updated into the memory;

Performing data update in the memory, and writing the updated data to the new physical address by the file system transmission unit; and erasing the data block to be updated, and updating the state mapping table and the Block address mapping table.

5. The apparatus according to claim 3, wherein the bad block management comprises a bad block detection and a bad block flag.

The device according to claim 5, further comprising:

a bad block detecting module, configured to cause the file system transmission unit to scan a management area of the entire file system during the initializing, by checking a bad block flag of a redundant area of the first page and the second page of each block Bit to determine whether the block is a bad block, if the block is a bad block, the block is recorded as a bad block in the block state mapping table, and if the block is not a bad block, the block state mapping table is The block record is a valid block.

7. The apparatus according to claim 5, further comprising: a bad block flag module, configured to cause the file system transmission unit to write to the non-linear flash memory by the file system transmission unit Determining whether the write operation is successful, if the write operation is successful, marking the bad block flag bit in the redundant area of the first page and the second page of the block in the non-linear flash memory as being With the state, if the write operation fails, the bad block flag is marked as a bad block, and then the block address mapping table is updated.

8. The apparatus according to claim 3, wherein the file system transfer unit converts the received logical address into a physical address when performing a read operation and a write operation.

9. The apparatus of claim 8, further comprising a write module for performing the following steps when performing a write operation:

Storing, in the file system transmission unit, data to be written, when the data to be written reaches a logical block, searching for a valid block in the state mapping table, and in the address mapping table The address of the logical block is mapped to the physical block address;

The data to be written is cyclically written to a physical block of the non-linear flash memory, and a state and a logical address of the physical block are recorded in a redundant area of a last page of the physical block;

Updating the state mapping table and the block address mapping table in the memory.

10. The apparatus according to claim 8, further comprising: a reading module, configured to perform the following steps when performing a read operation:

Mapping, by the block address mapping table, a physical block address of a read page, and a physical page address by the physical block address; and data.