TWI681296B - Apparatus and method and computer program product for accessing a memory card - Google Patents

Abstract

The invention introduces a memory-card access apparatus to at least include a processing unit for determining whether a logical block length of a memory card inserting into the memory-card access apparatus can be supported by a host; and when the logical block length of the memory card cannot be supported by the host, replying to the host with sense data that cannot be used to induce a subsequent data write through a host interface to respond to a request sense command issued by the host.

Description

Memory card access device and method, and computer program product

The invention relates to data access technology, in particular to a memory card access device and method and a computer program product.

The card reader is an interface device used to assist the interaction between the memory card and the computer host end, so that the computer host end can access the data stored in the memory card and store the read data on the host end. The computer host can drive the card reader through its Universal Serial Bus (USB) port. The memory card can be CF, SD, microSD or MMC card. Most card readers also provide the ability to write data. In order to access memory cards that use different formats, the card reader can detect the capacity and specifications of the memory card, and report its basic data and operating status to the host computer. However, the computer host may not be able to support certain memory card capabilities and erroneously access the data in the memory card, or even worse, damage the data in the memory card. Therefore, the present invention provides a memory card access device and method, and a computer program product to prevent data in the memory card from being damaged.

In view of this, how to mitigate or eliminate the above-mentioned deficiencies in related fields is really a problem to be solved.

This specification provides an embodiment of a memory card access device, which includes a host-side interface and a processing unit. The processing unit detects whether the logical block length of the memory card inserted into the memory card access device can be supported by the host; and responds to the host when it detects that the logical block length of the inserted memory card cannot be supported by the host The request sensing command issued by the terminal, which responds through the host interface cannot trigger the subsequent writing of the sensing data to the host.

This specification also provides an embodiment of a computer program product, which is loaded and executed by the processing unit of the card reader, and includes the following code: detecting whether the length of the logical block of the memory card inserted in the card reader can be used by the host Support; and when it is detected that the length of the logical block of the inserted memory card cannot be supported by the host, in response to the request sensing command sent by the host, the reply cannot trigger the subsequent writing of the sensing data to the host.

One of the advantages of the above embodiments is that the sensor data that cannot trigger subsequent writing by replying to the host that does not support the logical block length of the inserted memory card, so that the host does not update the boot area and file configuration in the memory card Table image to avoid losing all or part of the important information linked to the file.

Other advantages of the present invention will be explained in more detail with the following description and drawings.

The following description is a preferred implementation of the invention, and its purpose is to describe the basic spirit of the invention, but it is not intended to limit the invention. The actual content of the invention must refer to the scope of the following claims.

It must be understood that the words "comprising", "including", etc. used in this specification are used to indicate the existence of specific technical features, values, method steps, work processes, components and/or components, but do not exclude the addition of More technical features, values, method steps, job processing, components, components, or any combination of the above.

The terms such as "first", "second", and "third" are used in the claims to modify the elements in the claims, not to indicate that there is a priority order, pre-relationship, or an element Prior to another component, or the time sequence when performing method steps, is only used to distinguish components with the same name.

It must be understood that when an element is described as "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, and intermediate elements may appear. Conversely, when an element is described as "directly connected" or "directly coupled" to another element, there are no intervening elements present. Other words used to describe the relationship between elements can also be interpreted in a similar manner, such as "between" relative to "directly between", or "adjacent" relative to "directly adjacent" and so on.

Refer to Figure 1. The data access system may include a mobile phone as the host 110. Although the system of the embodiment takes a mobile phone as an example, those skilled in the art may also apply the host 110 to other computer devices, such as personal computers, laptop PCs, tablet computers, digital cameras, digital cameras, and so on. The host 110 can use a universal serial bus (Universal Serial Bus, USB) communication protocol to connect and drive the card reader 130. The memory card 150 can be inserted into the card reader 130 so that the host 110 can access the memory card 150 through the card reader 130. The card reader 130 can be a removable-media mass storage subsystem (removable-media mass storage subsystem), which is connected to the host 110 through its USB port. The host terminal 110 and the card reader 130 can communicate with each other by exchanging command blocks, data and status information defined by the standard, such as Universal Serial Bus Mass Storage Class: UFI Command Specification rev. published on December 14, 1998. 1.0. The card reader 130 can access the data in the memory card 150 through the Universal Flash Storage UFS communication protocol according to the command issued by the host 110.

Refer to Figure 2. The host 110 may include a processing unit 210 and a USB bus 230 for connecting to the card reader 130. When the processing unit 210 loads and executes software and/or firmware commands of the file system 211, UFI driver 213, and USB driver 215, specific functions are completed. The file system 211 is executed in a specific operating system and is used to control how to store data to and read data from the memory card 150. By dividing the data into logical segments and giving each segment a name, it is easy to separate and identify the information. The file system 211 uses specific structures (such as FAT12, FAT16, FAT32, exFAT, etc.) and logical rules to manage the information of these groups and their names. The UFI driver 213 controls the card reader 130 by sending the UFI command block defined by the standard. The UFI function module executed in the card reader 130 is used to process these command blocks. The exchange of all command blocks, data and status information can be achieved by passing packets on the USB bus 230, and these exchanges are managed by the USB driver 215. The host side also includes a memory 250, which is used to store data required for execution, such as variables, data tables, and data structures. The memory 250 can be a specific type of random access memory (Random Access Memory RAM) to provide volatile storage space.

When the memory card 150 is inserted into the card reader 130, some interactions between the host 110 and the card reader 130 are performed to initialize the connection between the host 110 and the memory card 150. Refer to Figure 3. In some embodiments, when the host 110 detects that a device is inserted into its USB port, it sends a test unit ready (TEST UNIT READY) command 312 to check whether the inserted device is ready. Since the memory card 150 has not been inserted into the card reader 130, the card reader 130 replies with a CSW fail message 318 to the host 110. The host terminal 110 sends a REQUEST SENSE command 322 for instructing the card reader 130 to transmit the sensing data of the specified logical unit to the host terminal 110. When the card reader 130 detects that the memory card 150 is inserted into the card reader 130, it responds to the media change (MEDIA CHANGED) sensing data 328 to the host 110. Then, the host terminal 110 sends the test unit ready command 332 again to check whether the inserted device is ready. Since the memory card 150 has been inserted into the card reader 130, the card reader 130 replies to the CSW pass message 338 to the host 110. Next, the host 110 sends a read capability command 342, requesting the card reader 130 to provide the current capability of inserting media. After querying the capability information, the card reader 130 generates and responds to the current capacity descriptor 348 to the host 110, for example, the 0th to 3rd byte records the total number of addressable blocks of the memory card 150 , And the 5th to 7th bytes record the length of each logical block in the memory card 150 (in bytes). The length of each logical block can be 512, 1K, 2K, 4K bytes, etc. During the initial operation of the media, the host 110 calculates the logical address of the storage boot sector, file allocation table image, etc. based on the capability information reported by the card reader 130, and issues a series of reads ( The READ) command 352 is given to the card reader 130 to obtain information such as the boot area and the file configuration table image stored at these logical addresses. Then, for the needs of subsequent operations, the host 110 modifies the relevant contents in the boot area and the file configuration table image, and issues a series of WRITE commands 362 to the card reader 130 for storing the updated contents back Memory card 150.

However, when the operating system or file system 211 running the host terminal 110 cannot support an excessively long logical block length, the updated boot area and file configuration table image will lose all or part of the important information linked to the file, resulting in a memory card The file stored in 150 is damaged. For example, the operating system or file system 211 only supports 512 bytes and cannot support the logical block length of 4K bytes. Although the UFI driver 213 receives 4K bytes of data per logical block through the USB interface, the operating system or file system 211 will only process the first 512 bytes of data in each logical block and ignore it The subsequent 3.5K bytes of data caused unexpected data loss after writing back to the memory card 150.

To solve the above-mentioned problems, the card reader 130 needs to implement a preventive mechanism to prevent the files stored in the memory card 150 from being damaged when the host 110 that does not support a specific logical block length is connected. Referring to FIG. 4, the card reader 130 at least includes a processing unit 410, which can be implemented in various ways, for example, using dedicated hardware or general-purpose hardware (such as a single processor, a multiprocessor with parallel processing capabilities, a graphics processor, or other tools Computing power), and provide the following functions when executing firmware or software instructions. The processing unit may include at least an Arithmetic and Logic Unit (ALU) and a Bit Shifter. The processing unit 110 is a multifunctional device that can perform arithmetic and logic functions. The arithmetic logic unit is responsible for performing mathematical operations (such as addition, subtraction, multiplication, division, etc.), Boolean operations (such as AND, OR, NOT, NAND, NOR, XOR, XNOR, etc.) or special function operations (such as trigonometric functions, square, 3rd party, nth power, square root, 3rd root, nth power, etc.). Generally, the mode selection input determines whether the arithmetic logic unit performs logical operations or arithmetic operations. The shifter is responsible for displacement calculation and bit rotation. The memory 420 may be connected to the processing unit 410 using a high-performance bus, and is used to store data required for execution, such as variables, data tables, and data structures. The memory 420 may be a specific type of random access memory to provide volatile storage space.

The processing unit 410, the memory 420, the USB interface 460, and the memory card interface 480 can be connected to each other by a system bus 450, and transfer data between devices using a specific communication protocol. The USB interface 460 may include a USB media access control layer (Media Access Control MAC) and a USB physical layer (PHY) for connecting to the USB port of the host 110. The processing unit 410 can load and execute corresponding UFI drivers and USB drivers for receiving and interpreting (interpret) UFI commands (such as test unit ready, request sensing, read, write and Erase commands, etc.), logical block numbers and data, and generate and send UFI messages, descriptors and data to the host 110. The memory card interface 480 may include a host controller (such as an SD or eMMC host controller) for connecting to the memory card 150. The processing unit 410 can load and execute a corresponding UFS driver program for generating and transmitting UFS commands (such as identification, reading, writing, and erasing commands, etc.), logical block numbers, and data to the memory card 150, and receiving And interpret the completion element (Completion Element CE) and data transmitted by the memory card 150.

The card reader 130 may perform an error prevention method to avoid the errors described above. First, the processing unit 410 detects whether the logical block length of the memory card 150 inserted in the card reader 130 cannot be supported by the host 110. When it is detected that the length of the logical block of the inserted memory card 150 cannot be supported by the host terminal 110, in response to receiving the request sensing command from the host terminal 110, the sensor data that cannot trigger subsequent processing is returned to the host through the host interface端110。 End 110.

Refer to Figure 5 for the detailed process. When the processing unit 410 receives the request sensing command from the host terminal 110 through the USB interface 460 (step S510), it may query the logical block length of the memory card 130 through the memory card interface 480 (step S520). In step S520, the processing unit 410 may send a read capacity (Read Capacity) command to the memory card 150 for requesting to provide the current capacity of the memory card 150. The processing unit 410 can receive a read capacity data response (Read Capacity Data Response) from the memory card 150, where the 4th to 7th bytes include its logical block length. The read capability command is a UFS SCSI command. It is understandable that step S520 may also be executed before step S510, and the present invention is not limited thereto. The processing unit 410 may store the length of the logical block in the readability data reply to the memory 420 until the memory card 150 is removed from the card reader 130.

When the processing unit 410 determines that the length of the logical block of the reply is a length that does not need to be checked, for example, 4K bytes (the path of "No" in step S530), the reply can trigger the sensing data (Sense Data) of the host 110 for subsequent processing ), for example, to indicate the sense key (Sense Key) of the media change (step S535). Sensing keys provide a basic type for reporting errors and exception status.

When the processing unit 410 determines that the logical block length of the reply is the length to be checked and the operating system and file system running on the host 110 supports the logical block length of the memory card 150 (the path of "Yes" in step S530 is followed by the step of S540" Yes path), then reply to the sensing data that can trigger subsequent processing by the host 110, for example, indicating the sensing key value of the media change (step S535).

When the processing unit 410 determines that the returned logical block length is the length that needs to be checked and the operating system or file system running on the host 110 does not support the logical block length of the memory card 150 (the path of "YES" in step S530 is followed by step S540) "No" path), the reply cannot trigger the subsequent writing of the sensing data of the host 110, for example, the sensing key value indicating that the media does not exist (MEDIA NOT PRESENT) or the media is protected by writing (WRITE PROTECTED MEDIA) To prevent the host 110 from updating the boot area and the file configuration table image, resulting in the loss of all or part of the important information linked to the file (step S535).

Since different operating systems use different configuration lengths, the processing unit 410 can determine the operating system running in the host 110 by requesting the value of the allocation length in the sensing command. The configuration length field of the requested sensing command describes the maximum number of bytes of sensing data that the host 110 can receive. For example, the maximum number of bytes of sensing data that can be received by the host running the Android operating system (Android), Windows 7/10/XP operating system (Windows 7/10/XP), and Mac operating system is 96 (that is, "0x60"), 18 (that is, "0x12") and 18, and the Android operating system or its file system does not support the logical block length of 4K bytes. As described above, the mapping information between the operating system or its file system and the length of the logical block to be checked can be stored in the memory 420 using any data structure, such as data tables, decision rules, etc., which is helpful for processing Unit 410 judges. In other embodiments, the mapping information as described above may also be reflected in the judgment logic of the code. In step S540, when the processing unit 410 detects that the value in the configuration length field of the request sensing command is "0x60", it is determined that the operating system or file system running on the host 110 does not support the logical block length of the memory card 150 . When the processing unit 410 detects that the value in the configuration length field of the request sensing command is "0x12", it determines that the operating system or file system running on the host 110 supports the logical block length of the memory card 150.

Referring to FIG. 6, the card reader can start the error prevention processing program 600 when it receives the request sensing command 322 to execute the method flow shown in FIG. 5. In the error prevention processing program 600, the processing unit 410 may send a read capability command 612 to the memory card 150 through the memory card interface 480, and receive a read capability data reply 618 from the memory card 150 to complete the logic area of the memory card 150 Block length query. It is understandable that a person skilled in the art can execute the sending of the reading capability command 612 before starting the error prevention processing program 600, or the sending of the reading capability command 612 and the reception of the reading capability data reply 618 can be executed on Before starting the error prevention processing program 600, the present invention is not so limited. When the processing unit 410 determines that the returned logical block length is the length that does not need to be checked (the path of "No" in step S530), or the returned logical block length is the length that needs to be checked and the operating system or file running on the host 110 The system supports the logical block length of the memory card 150 (the "YES" path in step S530 is followed by the "YES" path in step S540), and then responds to the sensing data 628 that can trigger subsequent processing by the host 110 (step S535). Subsequent processing may include the transmission of the test unit ready command 332 and the read capability command 342 and the reception of the corresponding message 338 and the current capability description element 348. Subsequent processing may also include reading, modifying, and writing the boot area and file configuration table images as described above.

Referring to FIG. 7, in the error prevention process 600, when the processing unit 410 determines that the logical block length of the reply is the length to be checked and the operating system or file system running on the host 110 does not support the logical block length of the memory card 150 ( The path of "Yes" in step S530 is followed by the path of "No" in step S540), the reply cannot trigger the subsequent writing of the sensing data 718 of the host 110, for example, indicating that the media does not exist or is written to the protection media Key value (step S545). Subsequent writing may include the reading, modification, and writing of the boot area and file configuration table images as described above.

The method steps of the data access control executed by the processing unit 410 can be implemented using computer program products composed of one or more functional modules. These functional modules are stored in a non-volatile storage device, and can be loaded and executed by the processing unit 410 at a specific time point. Referring to FIG. 8, the processing unit 110 executes the host interface driver module 810 to complete the operations of steps S510, S535 and S545, executes the memory card interface driver module 820 to complete the operations of step S520, and executes the error prevention processing module 830 to complete the step S530 And the operation of S540. Data transfer between the host interface driver module 810, the memory card interface driver module 820, and the error prevention processing module 830 can be accomplished through function calls, global variables, and so on. The host interface driver module 810 may include a USB interface 460 driver, such as a corresponding UFI driver and USB driver, and the memory card interface driver module 820 may include a memory card interface 480 driver, such as a UFS driver.

All or part of the steps in the method of the present invention can be implemented by a computer program, such as a computer operating system, a specific hardware driver in the computer, or a software application program. In addition, it can also be implemented in other types of programs as shown above. A person skilled in the art can write the method of the embodiment of the present invention into a computer program, which will not be described for simplicity. The computer program implemented according to the method of the embodiment of the present invention can be stored in a suitable computer-readable data carrier, such as a DVD, CD-ROM, USB disk, or hard disk, or can be placed on a network (for example, the Internet Network server.

Although the elements described above are included in FIG. 4, it is not excluded that more other additional elements are used without violating the spirit of the invention, and a better technical effect has been achieved. In addition, although the flowchart in FIG. 5 is executed in a specified order, without violating the spirit of the invention, a person skilled in the art can modify the order between these steps on the premise of achieving the same effect. Therefore, the present invention does not It is not limited to use only the order described above. In addition, those skilled in the art can also integrate several steps into one step, or in addition to these steps, perform more steps sequentially or in parallel, and the present invention is not limited thereby.

Although the present invention is described using the above embodiments, it should be noted that these descriptions are not intended to limit the present invention. On the contrary, this invention covers obvious modifications and similar settings for those skilled in the art. Therefore, the scope of the claims of the application must be interpreted in the broadest way to include all obvious modifications and similar settings.

110‧‧‧Host

130‧‧‧Card reader

150‧‧‧Memory card

210, 410‧‧‧ processing unit

211‧‧‧ File System

213‧‧‧ UFI driver

215‧‧‧USB driver

230‧‧‧USB bus

250, 420‧‧‧ memory

312、332‧‧‧Test unit ready command

318‧‧‧CSW failure message

322‧‧‧ Request sensing command

328‧‧‧ Sensing data of media change

338‧‧‧CSW message

342‧‧‧Read Ability Command

348‧‧‧ current ability description element

352‧‧‧Read command

358‧‧‧Write command

450‧‧‧System bus

460‧‧‧USB interface

480‧‧‧Memory card interface

S510~S545‧‧‧Method steps

600‧‧‧Procedure for error prevention

612‧‧‧Read Ability Command

618‧‧‧Reading ability data reply

628‧‧‧ Sensing data that can trigger subsequent processing on the host

718‧‧‧Cannot trigger the subsequent writing of sensing data on the host

810‧‧‧Host interface driver module

820‧‧‧Memory card interface driver module

830‧‧‧ Error prevention processing module

FIG. 1 is a schematic diagram of a data access system according to an embodiment of the invention.

Figure 2 is a block diagram of the host side.

FIG. 3 is a sequence diagram of interaction between the host and the card reader in some embodiments.

FIG. 4 is a system architecture diagram of a card reader according to an embodiment of the invention.

5 is a flowchart of a memory card access method according to an embodiment of the invention.

6 and 7 are sequence diagrams of interaction between the host and the card reader according to an embodiment of the invention.

8 is a schematic diagram of a software module for data access in a card reader according to an embodiment of the present invention.

S510~S545‧‧‧Method steps

Claims (13)

A memory card access device includes: a host-side interface, coupled to a host-side; and a processing unit, coupled to the host-side interface, for detecting a card inserted into the memory-card access device Whether a logical block length of the memory card can be supported by the host side; and when it is detected that the logical block length of the inserted memory card cannot be supported by the host side, in response to the host side A request sensing command issued by the host-side interface replies to the host-side with a sensing data that cannot trigger subsequent writing. The memory card access device according to claim 1, comprising: a memory card interface coupled to the processing unit, wherein the processing unit interrogates the memory card through the memory card interface for obtaining all The length of the logical block of the memory card. The memory card access device according to claim 1, wherein when the processing unit determines that the length of the logical block of the memory card is a length that does not need to be checked, it responds to the Request a sensing command and reply to the host through the host interface a piece of sensing data that can trigger subsequent processing by the host. The memory card access device according to claim 1, wherein when the processing unit determines that the length of the logical block of the memory card is a length that needs to be checked and an operating system and a file run by the host When the system supports the length of the logical block of the memory card, in response to the request sensing command issued by the host, a response data that can trigger subsequent processing by the host is returned through the host interface To the host. The memory card access device according to any one of claims 3 to 4, wherein the sensing data capable of triggering subsequent processing by the host is a sensing key value indicating that the media is changed. The memory card access device according to claim 1, wherein when the processing unit determines that the length of the logical block of the memory card is a length that needs to be checked and an operating system or a file running on the host side When the system does not support the length of the logical block of the memory card, in response to the request sensing command issued by the host, replying through the host interface cannot trigger subsequent writing by the host. The sensing data is given to the host. The memory card access device according to claim 6, wherein the sensing data that cannot trigger subsequent writing by the host is a sensing key value indicating that the media does not exist or the media is protected from writing. The memory card access device according to claim 1, wherein the processing unit determines whether the host supports the memory card by detecting a value in a configuration length field of the request sensing command The length of the logical block. A computer program product for loading and execution by a processing unit of a card reader, including the following program code: detecting whether a logical block length of a memory card inserted in the card reader can be Host support; and when it is detected that the length of the logical block of the inserted memory card cannot be supported by the host, in response to a request sensing command issued by the host, the reply cannot trigger subsequent writes The inputted sensing data is given to the host. The computer program product according to claim 9 further includes the following program code: query the memory card to obtain the length of the logical block of the memory card. The computer program product according to claim 9, further comprising the following program code: When it is determined that the length of the logical block of the memory card is the length that needs to be checked and an operating system or a file system running on the host side When the length of the logical block of the memory card is not supported, in response to the request sensing command issued by the host, a reply that cannot trigger a subsequent write of sensing data by the host to the host end. The computer program product according to claim 11, wherein the sensing data that cannot trigger subsequent writing by the host is a sensing key value indicating that the media does not exist or the media is protected from writing. The computer program product described in claim 9 further includes the following program code: Determine whether the host supports the memory card by detecting the value in a configuration length field of the request sensing command Describe the logical block length.

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