A firmware fast loading method and circuit of a photoelectric DSP chip and an optical module

Abstract

The application provides a firmware fast loading method and circuit of an optical-electric DSP chip and an optical module. The method is applied to a DSP unit which is installed in the optical module and is used for executing a starting program. The DSP unit is electrically connected with an MCU unit of the optical module and obtains loading information of the MCU unit. The method comprises the following steps: obtaining first information and obtaining second information according to the first information. The file size of the first information is smaller than that of the second information, and the first information contains communication parameter information used for obtaining the second information. The second information contains target firmware of the DSP unit. The application can improve the loading speed of the firmware of the DSP chip, reduce the development work of the control program of the MCU and has good compatibility on the basis of saving hardware cost.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, specifically to a method, circuit, and optical module for fast firmware loading of an optoelectronic DSP chip. Background Technology

[0002] In existing technologies, to reduce the manufacturing cost of optical modules, most optical module manufacturers typically do not configure a separate non-volatile memory (such as Flash) for the digital signal processing (DSP) chip. Instead, they integrate the firmware required by the DSP chip into the same Flash memory used by the microcontroller unit (MCU) in the optical module. Accordingly, the boot process of the DSP chip relies on the MCU reading the DSP firmware data from its shared Flash memory and transmitting the firmware to the DSP chip via a specific communication interface. While this approach achieves the integration of storage resources and cost control, it also introduces technical challenges regarding firmware transmission speed and program compatibility. Therefore, optimizing firmware transmission speed and program compatibility has become a key issue that DSP chip manufacturers are continuously focusing on and urgently need to address.

[0003] One existing solution relies on the boot ROM of the DSP chip to download firmware via low-speed protocols such as I2C / UART. The drawback of this solution is its slow speed. Optical modules typically have a limited number of I2C interfaces, generally using general purpose input / output (GPIO) pins to simulate I2C communication. To ensure communication accuracy, the maximum communication rate is 400kHz. Downloading 1MB of firmware takes 20 seconds, which is too long and cannot meet the requirements for fast booting of the DSP chip.

[0004] Another existing solution relies on the BootROM of the DSP chip to download firmware via high-speed SPI / USB. While this solution achieves relatively fast firmware transfer speeds based on SPI / USB, different DSP chips have different download formats. When using different DSP chips, the MCU program of the optical module needs to be developed for the proprietary transmission protocol of the DSP chip's BootROM, and the original MCU's communication program needs to be significantly or even completely rewritten, resulting in poor compatibility. Summary of the Invention

[0005] The primary objective of this invention is to provide a fast firmware loading method for optoelectronic DSP chips, thereby addressing the issues of slow loading speed and poor compatibility in existing optoelectronic DSP chips.

[0006] The second objective of this invention is to provide a circuit for implementing the above-mentioned fast firmware loading method for the optoelectronic DSP chip.

[0007] A third objective of this invention is to provide an optical module that includes a firmware fast loading circuit for the aforementioned optoelectronic DSP chip.

[0008] To achieve the aforementioned first objective, this invention provides a fast firmware loading method for an optoelectronic DSP chip, applied to a DSP unit. The DSP unit is installed in an optical module and executes a startup program. The DSP unit is electrically connected to the MCU unit of the optical module and obtains loading information from the MCU unit. Obtaining the loading information from the MCU unit includes: obtaining first information and obtaining second information based on the first information; the file size of the first information is smaller than the file size of the second information, and the first information contains communication parameter information used to obtain the second information; the second information contains the target firmware of the DSP unit.

[0009] As can be seen from the above scheme, the DSP unit of the present invention first downloads a smaller amount of first information from the MCU unit, and then downloads a larger amount of second information from the MCU unit based on the first information, thereby achieving rapid loading of the required target firmware. Since the present invention encapsulates the secondary development work of the DSP unit's proprietary download protocol within the first information, the MCU unit does not need to concern itself with the specific implementation of the DSP unit's download format. When the DSP unit needs to be replaced, the control program inside the MCU unit only needs to make minor adjustments based on the first information corresponding to the replaced DSP unit (e.g., changing the clock rate, pin configuration, firmware storage address, etc.), rather than significantly adjusting the MCU's control program (e.g., adjusting the file format, transmission order, control commands, etc. according to the proprietary download protocol for the replaced DSP unit). This greatly reduces the development work of the MCU's control program and improves its compatibility. Furthermore, since the MCU unit can directly transmit the second information containing the entire target firmware to the DSP unit at once without needing to know the specific content of the target, the transmission interface of the MCU unit can be simplified.

[0010] A further solution is that the first information includes an information part and an execution part; the second information includes firmware parsing information; the startup program further includes: after obtaining the first information from the MCU unit, loading the first information; determining communication parameter information based on the information part, and jumping to the execution part; the execution part includes: controlling communication with the MCU unit based on the communication parameter information, obtaining the second information from the MCU unit; determining the firmware parsing information from the second information, loading the target firmware into the firmware storage area based on the firmware parsing information, and jumping to the firmware storage area.

[0011] Therefore, the firmware parsing information used to parse the target firmware can be encapsulated in the second information along with the target firmware and transmitted to the DSP unit in one go. The DSP unit will then receive the second information and store it in a temporary buffer (e.g., a preset address in the SRAM of the DSP unit). It will then obtain the firmware parsing information from the second information and load the target firmware from the temporary buffer at the loading address indicated by the firmware parsing information according to the firmware information.

[0012] A further solution is that the first information includes an information part and an execution part; the second information includes firmware parsing information; the startup program further includes: after obtaining the first information from the MCU unit, loading the first information; determining communication parameter information based on the information part, and jumping to the execution part; the execution part includes: controlling communication with the MCU unit based on the communication parameter information, obtaining the second information from the MCU unit; determining the firmware parsing information from the second information, loading the target firmware into the firmware storage area based on the firmware parsing information, and jumping to the firmware storage area.

[0013] Therefore, the present invention encapsulates the firmware parsing information used to parse the target firmware in the first information, so that the boot program can parse the firmware parsing information from the information part before obtaining the second information. Thus, when the DSP unit obtains the target firmware in the second information, it can directly load the target firmware according to the firmware parsing information. Since there is no need to load it in the temporary buffer, the loading speed of the target firmware can be further improved.

[0014] A further approach is to include the following steps in the startup process: determining verification information based on the information section; after obtaining the target firmware but before jumping to the firmware storage area, the process includes: verifying the target firmware based on the verification information; jumping to the firmware storage area after successful verification; and resetting if the verification fails.

[0015] Therefore, it can be seen that verification can be used to verify the sender corresponding to the target firmware and protect the target firmware.

[0016] A further approach is that the startup procedure includes determining decompression information based on the information section; after obtaining the target firmware but before jumping to the firmware storage area, it includes: performing a decompression operation on the target firmware based on the decompression information.

[0017] Therefore, it can save storage space in the MCU unit, and when the decompression speed is greater than the transmission speed, the firmware loading speed can be further improved.

[0018] A further approach is to perform an integrity check on the first information before obtaining the second information based on the first information.

[0019] Therefore, it can be seen that complete first information can be received.

[0020] A further solution is that when obtaining the first information from the MCU unit, the first information is obtained from the MCU unit through a first preset communication method; when obtaining the target firmware from the MCU unit, the target firmware is obtained through a second preset communication method based on the communication parameter information; the signal transmission rate when using the second preset communication method is greater than the signal transmission rate when using the first preset communication method.

[0021] Therefore, it can be seen that by using existing communication methods, a smaller initial information can be downloaded at a low clock speed, and a larger DSP firmware can be downloaded at a high clock speed. Since the initial information is small, it is convenient to use various existing communication methods for fast transmission, reducing the requirements for the transmission rate of the communication method, which is convenient to implement and reduces development work.

[0022] To achieve the second objective mentioned above, the present invention provides a fast firmware loading circuit for an optoelectronic DSP chip, comprising: a DSP unit and an MCU unit, wherein the DSP unit is connected to the MCU unit; the DSP unit includes a boot read-only memory and a random access memory, wherein the boot read-only memory stores a boot program; the MCU unit includes a non-volatile memory, wherein the non-volatile memory stores first information and second information; the DSP unit implements the aforementioned fast firmware loading method, wherein the first information and second information acquired by the DSP unit are loaded into the random access memory.

[0023] As can be seen from the above scheme, the present invention uses the MCU unit to store the target firmware required for the DSP unit to start, and uses the first information to download the second information containing the target firmware to the DSP unit. While saving hardware costs, it can also ensure the transmission speed of the second information and the compatibility of the MCU unit's control program.

[0024] A further approach is to include a one-time programmable memory in the DSP unit, which stores the root key used to decrypt the target firmware.

[0025] Therefore, it is evident that the received target firmware can be easily decrypted.

[0026] To achieve the third objective mentioned above, the present invention provides an optical module, including a housing, wherein the housing contains a firmware fast loading circuit for the aforementioned optoelectronic DSP chip.

[0027] As can be seen from the above solution, the optical module provided by the present invention enables users to develop control programs for MCU units without having to develop according to the private download protocol of the DSP unit. Instead, they can develop based on the first information of the provided DSP unit. Since there is no need to pay attention to the specific implementation of the private download protocol, the development work of the user's MCU unit control program can be reduced, and it is convenient for users to replace different types of DSP units, which has good compatibility and improves product competitiveness. Attached Figure Description

[0028] Figure 1 This is a circuit framework diagram of an embodiment of the firmware fast loading circuit for the optoelectronic DSP chip of the present invention.

[0029] Figure 2This is a flowchart of an embodiment of the fast firmware loading method for the optoelectronic DSP chip of the present invention.

[0030] Figure 3 yes Figure 2 The detailed flowchart of step S6.

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0032] After the DSP unit of the present invention is powered on, it first obtains the first information from the MCU unit, and then obtains the second information containing the target firmware from the MCU unit through the first information. The target firmware is loaded into the firmware storage area, and the execution is performed in the firmware storage area to complete the fast startup. During this process, the MCU unit does not need to care about the specific implementation of the DSP chip download format.

[0033] Example of a firmware fast loading circuit for an optoelectronic DSP chip:

[0034] See Figure 1 This embodiment includes a DSP unit 1 and an MCU unit 2. The DSP unit 1 includes a boot read-only memory 11, a random access memory 12, and a one-time programmable memory 13. The MCU unit 2 includes a non-volatile memory 21. The DSP unit 1 is electrically connected to the MCU unit 2.

[0035] The boot read-only memory 11 stores a boot program. This boot program is executed after the DSP unit 1 is powered on or reset. The boot program is permanently stored in the boot read-only memory 11 at the factory and cannot be changed. In this embodiment, the boot read-only memory 11 is specifically a BootROM.

[0036] The startup program is used to obtain first information from MCU unit 2, load the first information into random access memory 12, perform integrity verification and parsing on the obtained first information, and jump to the execution part of the first information after passing the integrity verification and parsing.

[0037] Random access memory 12 is used to store temporary data of DSP unit 1, including storing first information and second information obtained by DSP unit 1 from MCU unit 2. In this embodiment, random access memory 12 is a specific SRAM.

[0038] The one-time programmable memory 13 is used to store the key for decrypting the target firmware and the key for verifying the target firmware. In this embodiment, the one-time programmable memory 13 is specifically an eFuse.

[0039] The non-volatile memory 21 stores first information and second information. In this embodiment, the non-volatile memory 21 is specifically a Flash memory.

[0040] When the first information, as a downloader program, is executed in DSP unit 1, it downloads the second information, including the target firmware, from MCU unit 2. This second information then loads the target firmware into non-volatile memory 21 for execution. The target firmware is the firmware required to be loaded when DSP unit 1 starts up.

[0041] The first information includes an information section and an execution section. In this embodiment, the information section and the execution section are arranged in sequence, with the information section being the file header and the execution section being the file body. The file header includes metadata describing the file body. The file body includes code that implements DSP firmware download. By parsing the file header, basic attribute information, firmware parsing information, communication parameter information, verification information, and decompression information can be obtained. The parsed firmware parsing information, communication parameter information, verification information, and decompression information are loaded into the random access memory 12 for use when executing the file body.

[0042] The basic attribute information describes the version information and checksum, which is used to verify the integrity of the file header and file body.

[0043] The firmware parsing information describes the information of the DSP firmware to be received, including the size of the DSP firmware and the address where the DSP firmware is loaded in the random access memory 12. The DSP firmware may include multiple sub-firmwares, the size of the DSP firmware includes the size of each sub-firmware, and the address where the DSP firmware is loaded includes the address where each sub-firmware is loaded. Through the firmware parsing information, the DSP unit 1 can parse the received target firmware and load the target firmware into the random access memory 12.

[0044] The communication parameter information describes the communication parameters required for DSP unit 1 to download the target firmware from MCU unit 2. In this embodiment, the communication parameter information includes the use of SPI communication as the communication method, and DSP unit 1 acting as the host to provide the required SPI clock information to MCU unit 2.

[0045] The verification information describes whether the received target firmware needs to be verified, and if verification is required, the attribute information corresponding to the verification items. In this embodiment, the verification items include signature verification items and decryption items.

[0046] The signature verification item's attribute information includes signature verification enable information, signature verification algorithm information, and signature verification required key information. Signature verification enable information describes whether signature verification is required for the received target firmware. Signature verification algorithm information describes the signature verification algorithm used when verifying the received target firmware. Signature verification required key information specifies the address of the signature verification key corresponding to the currently used signature verification algorithm in the one-time programmable memory 13.

[0047] The decryption project's attribute information includes decryption enable information, decryption algorithm information, and decryption key information. Decryption enable information describes whether the received target firmware needs to be decrypted. Decryption algorithm information describes the decryption algorithm used to decrypt the received target firmware. Decryption key information describes the address of the decryption root key corresponding to the currently used decryption algorithm in the one-time programmable memory 13.

[0048] The decompression information describes whether the received target firmware needs to be decompressed, and if so, the decompression algorithm to be used. When some target firmware is large, it can be pre-compressed in MCU unit 2. DSP unit 1 obtains the compressed target firmware, and then determines the decompression algorithm to be used for local decompression based on the decompression information. This can save storage space in MCU unit 2 and further speed up the loading of target firmware by DSP unit 1.

[0049] When jumping to the file body for execution, the target firmware is obtained from MCU unit 2 according to the communication parameter information, and possible verification and decompression operations are performed on the target firmware based on the specific verification and decompression information. Then, based on the firmware parsing information, the target firmware is loaded into random access memory 12. The area in random access memory 12 where the target firmware is stored is the firmware storage area. Finally, the jump is made to the firmware storage area to realize the loading of the target firmware, thus completing the fast loading of the firmware of the DSP chip.

[0050] In different embodiments, the DSP unit 1 can be integrated on one chip, and the MCU unit 2 can be integrated on another chip.

[0051] In different embodiments, the DSP unit 1 includes an independent DSP chip, which is responsible for the execution of the specific startup program, first information and target firmware. The read-only memory 11, random access memory 12 and one-time programmable memory 13 are electrically connected to the DSP chip as discrete components. The DSP unit 1 also includes an independent MCU chip, which is electrically connected to the DSP chip to realize data transmission. The non-volatile memory 21 is electrically connected to the MCU chip as a discrete component.

[0052] Example of a fast firmware loading method for optoelectronic DSP chips:

[0053] This embodiment is based on the firmware fast loading circuit of the aforementioned optoelectronic DSP chip.

[0054] See Figure 2 This embodiment is implemented by executing a computer program, and specifically includes the following steps:

[0055] S1: Obtain first information from the MCU unit through the first preset communication method and load it into the random access memory.

[0056] In this embodiment, the first preset communication method is I2C communication, the file size of the first information is 3KB, and it is transmitted at a rate of 100Kbps.

[0057] It should be noted that since the file size of the first information is relatively small (generally less than 4KB), which is much smaller than the file size of the second information (about 500KB), the I2C communication method can ensure fast and accurate transmission of the first information.

[0058] In other embodiments, the first preset communication method may also be UART or JTAG.

[0059] S2: Determine whether the first piece of information has passed the integrity check.

[0060] In this embodiment, the integrity of the file header and file body is verified using CRC32, based on the checksum provided in the file header of the first information. If the integrity verification fails, it indicates a problem with the transmission of the first information, and step S9 is executed to perform a reset operation, returning to step S1. If the integrity verification passes, it means the first information has been successfully transmitted from the MCU unit to the DSP unit, and step S3 is then executed.

[0061] S3: Parse the file header of the first information.

[0062] The firmware parsing information, communication parameter information, verification information, and decompression information obtained from the file header are loaded into the random access memory for subsequent steps.

[0063] S4: Jump to the file body of the first information.

[0064] S5: Obtain second information from the MCU unit through the second preset communication method.

[0065] In this embodiment, the signal transmission rate of the second preset communication method is greater than that of the first preset communication method. The second preset communication method is SPI communication, which enables SPI communication with the MCU unit based on communication parameter information. The DSP unit acts as the master, and the MCU unit acts as the slave.

[0066] In other embodiments, depending on different communication parameter information, the second preset communication method may also be MDIO or USB.

[0067] S6: Determine that the target firmware can be executed normally.

[0068] By determining whether the target firmware in the second information can be executed normally, erroneous target firmware can be avoided. If it is determined that it cannot be executed normally, it indicates that there is a problem with the target firmware itself or the transmission process, and step S9 needs to be executed to perform a reset operation and return to step S1. If it is determined that it can be executed, then step S7 continues.

[0069] S7: Load the target firmware into the firmware storage area of ​​the random access memory.

[0070] Specifically, the target firmware is loaded into the firmware storage area of ​​the random access memory based on the firmware parsing information.

[0071] S8: Jump to the firmware storage area.

[0072] Specifically, execution jumps to the first address of the firmware storage area based on the firmware parsing information.

[0073] See also Figure 3 , Figure 3 The specific process of step S6 above is shown.

[0074] First, execute step S61 to determine whether signature verification is required. Specifically, based on the signature verification enable information, determine whether signature verification is required for the received target firmware. If yes, continue to step S62; otherwise, proceed to step S63.

[0075] When signature verification is required based on the signature enable information, step S62 is executed to determine whether the target firmware passes ECC verification. After determining that signature verification is required based on the signature enable information, the signature verification algorithm to be used is determined based on the signature verification algorithm information, and the signature verification key to be used is determined based on the key information required for signature verification. This embodiment uses the ECC algorithm for signature verification, and the corresponding signature verification key ECC_PUBLIC_KEY is obtained from the one-time programmable memory. Through the signature verification operation, it can be ensured that the target firmware has not been tampered with by a man-in-the-middle. If the target firmware passes ECC verification, step S63 is executed; if the target firmware fails ECC verification, the process jumps to step S9.

[0076] When the target firmware is confirmed to have passed ECC verification, step S63 is executed to determine whether decryption is required. Specifically, the decryption enable information is used to determine whether the received target firmware needs to be decrypted. If decryption is required, step S64 is executed to obtain the corresponding key combination for the target firmware based on the EFUSE decryption root key and decrypt the target firmware. If not, the process proceeds to step S65.

[0077] When decryption is required, the decryption algorithm is determined based on the decryption algorithm information, and the corresponding decryption root key in the one-time programmable memory is determined based on the key information required for decryption. This embodiment uses the SM4 decryption algorithm. The decryption algorithm information includes a key derivation level (specifically three levels) and three levels of CONTENT inputs (C, D, E). The decryption root key SM4_KEY corresponding to the one-time programmable memory is used to sequentially decrypt C, D, and E to obtain the final firmware decryption key. The target firmware is then decrypted using SM4 based on this final firmware decryption key. Through the encryption and decryption operations on the target firmware, the target firmware itself can be protected from leakage.

[0078] Then, proceed to step S65 to determine whether decompression is required. Based on the decompression information, determine whether the received target firmware needs to be decompressed. If decompression is required, proceed to step S66 to decompress the target firmware, wherein the target firmware is decompressed according to the decompression algorithm indicated in the decompression information; otherwise, proceed to step S7.

[0079] Optical module example:

[0080] The optical module of this embodiment includes a housing, and the housing contains the firmware fast loading circuit of the optoelectronic DSP chip of the above embodiment.

[0081] In summary, this invention employs a two-stage boot scheme to shorten firmware boot time. First, a smaller amount of initial information is loaded via a low-speed bus, followed by a larger amount of second information containing the DSP firmware downloaded via a high-speed bus. The total boot time can be reduced to less than 0.5 seconds. This invention eliminates the need for adding non-volatile memory to the DSP chip to store the firmware, reducing hardware costs. Furthermore, the MCU program does not need to concern itself with the specific implementation of the DSP chip's download format, thus avoiding compatibility issues. The MCU program can transfer the entire DSP firmware to the DSP chip in one go, without needing to know the specific content of each sub-module, simplifying the transmission interface.

[0082] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fast loading firmware of an optoelectronic DSP chip, applied to a DSP unit, the DSP unit being configured to be installed in an optical module, execute a start program, and be electrically connected to an MCU unit of the optical module and obtain loading information of the MCU unit, and the method comprising: obtaining the loading information of the MCU unit, including obtaining first information and obtaining second information according to the first information, wherein a file size of the first information is smaller than a file size of the second information, and the first information contains communication parameter information for obtaining the second information, and the second information contains target firmware of the DSP unit; the first information comprising an information part and an execution part; the start program comprising: loading the first information after obtaining the first information from the MCU unit; determining the communication parameter information according to the information part and jumping to the execution part; the execution part comprising: controlling communication with the MCU unit based on the communication parameter information, and obtaining the second information from the MCU unit; loading the target firmware in a firmware storage area based on firmware parsing information, and jumping to the firmware storage area, wherein the firmware parsing information comprises a size and a loading address of the target firmware. 2.The method of claim 1, wherein: the second information comprises firmware parsing information; and the execution part comprises determining the firmware parsing information from the second information. 3.The method of claim 1, wherein: the start program comprises determining firmware parsing information and the communication parameter information according to the information part, and jumping to the execution part. 4.The method of claim 3, wherein: the start program comprises determining check information according to the information part; and before jumping to the firmware storage area after obtaining the target firmware, the method comprises checking the target firmware based on the check information, jumping to the firmware storage area after the check passes, and resetting when the check fails. 5.The method of claim 3, wherein: the start program comprises determining decompression information according to the information part; and before jumping to the firmware storage area after obtaining the target firmware, the method comprises performing a decompression operation on the target firmware based on the decompression information. 6.The method of claim 1, wherein: before obtaining the second information according to the first information, the method comprises performing an integrity check on the first information. 7.The method of any one of claims 1 to 5, wherein: when obtaining the first information from the MCU unit, the method comprises obtaining the first information from the MCU unit through a first preset communication mode. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ When the second information is acquired from the MCU unit, the second information is acquired from the MCU unit by a second preset communication mode based on the communication parameter information. A signal transmission rate when the second preset communication mode is applied is greater than a signal transmission rate when the first preset communication mode is applied.

8. A firmware fast loading circuit of an optoelectronic DSP chip, characterized in that, Comprise: A DSP unit and an MCU unit, the DSP unit being connected to the MCU unit; The DSP unit comprises a start read-only memory and a random access memory, and the start read-only memory stores a start program; The MCU unit comprises a non-volatile memory, and the non-volatile memory stores first information and second information; The DSP unit realizes the firmware fast loading method of the photoelectric DSP chip in any one of claims 1 to 7, wherein the first information and the second information acquired by the DSP unit are loaded in the random access memory.

9. The firmware fast loading circuit of the photoelectric DSP chip according to claim 8, characterized in that: The DSP unit further comprises a one-time programmable memory, and the one-time programmable memory stores a root key for decrypting the second information.

10. An optical module comprising a shell, characterized in that: The shell comprises the firmware fast loading circuit of the photoelectric DSP chip according to claim 8 or 9.

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