Fan rotating speed control method and system based on CPLD and BMC cooperation

Abstract

The application provides a fan rotating speed control method and system based on CPLD and BMC. The method is applied to a fan rotating speed control system based on CPLD and BMC. A BMC module transmits an ACTIVE signal for representing whether the BMC module is normally running to a CPLD module through a first GPIO interface. When the ACTIVE signal represents that the BMC module is abnormally working, the CPLD module collects first over-temperature information reported by a CPU, and performs corresponding speed control on a cooling fan or performs server shutdown control according to the over-temperature information through a first PWM interface and a first TACH interface. The BMC module and the CPLD module cooperatively control the fan, so that when the BMC module suddenly abnormally works, the rotating speed of the cooling fan cannot be normally controlled, the cooling fan cannot reach an expected state, a catastrophic event occurs on a server mainboard, and the reliability and safety of a server product are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of computer, in particular to a fan speed control method and system based on CPLD and BMC. BACKGROUND

[0002] In recent years, with the deepening of informatization in various industries, the popularity of server applications is also rising, and the problems of information security and product reliability are coming.

[0003] In the design of server mainboard, the common cooling method is to use cooling fans to reduce the system temperature, so as to avoid the failure or burning of components due to high temperature. For the existing server cooling design, the BMC module directly controls the cooling fan according to the data read from the internal temperature sensor of the server; however, in the long-term operation of the system, the BMC module may be abnormal and invalid, and cannot control the cooling fan, so that the cooling fan cannot reach the expected state, resulting in catastrophic events of the server mainboard, and there is a great safety hazard. SUMMARY

[0004] The purpose of the present application is to provide a fan speed control method and system based on CPLD and BMC, which cooperatively controls the fan through the BMC module and the CPLD module, avoids the abnormality of the BMC module, and cannot normally control the speed of the cooling fan, so that the cooling fan cannot reach the expected state, resulting in catastrophic events of the server mainboard, and improves the reliability and safety of the server product.

[0005] In a first aspect, the application provides a fan speed control method based on CPLD and BMC. The method is applied to a fan speed control system based on CPLD and BMC. The system comprises a CPLD module, a BMC module, and a cooling fan. The CPLD module is connected with the cooling fan through a first PWM interface and a first TACH interface. The BMC module is connected with the CPLD module through a second PWM interface, a second TACH interface, a first GPIO interface, and an over-temperature information interface. The BMC module is also connected with a temperature sensor on a server mainboard through an I2C interface. The BMC module is also connected with a CPU through a second GPIO interface. The CPLD module is connected with the CPU through a third GPIO interface. The method comprises the following steps: the BMC module transmits an ACTIVE signal representing whether the BMC module is normally running to the CPLD module through the first GPIO interface; when the ACTIVE signal represents that the BMC module is normally working, the BMC module reads temperature information of each module collected by the temperature sensor on the server mainboard through the I2C interface, and monitors and controls the speed of the cooling fan according to the read temperature information through the second PWM interface and the second TACH interface; the BMC module receives first over-temperature information sent by the CPU through the second GPIO interface, monitors and records the first over-temperature information for user maintenance and viewing, sends the first over-temperature information to the CPLD module through the over-temperature information interface, and controls the fan or performs shutdown control according to the first over-temperature information; when the ACTIVE signal represents that the BMC module is abnormally working, the CPLD module receives the first over-temperature information reported by the CPU through the third GPIO interface, and performs corresponding speed control on the cooling fan through the first PWM interface and the first TACH interface, or performs server shutdown control according to the first over-temperature information.

[0006] Further, the system further comprises a power regulator module, and the CPLD module is connected with the power regulator module through the third GPIO interface. The method further comprises the following steps: the CPLD module collects second over-temperature information sent by the power regulator module, and sends the second over-temperature information to the BMC module; when the ACTIVE signal represents that the BMC module is normally working, the BMC module controls the fan or performs shutdown control according to the second over-temperature information; when the ACTIVE signal represents that the BMC module is abnormally working, the CPLD module controls the fan or performs shutdown control according to the second over-temperature information.

[0007] Further, the first over-temperature information and the second over-temperature information correspond to alarm levels; the step of controlling the fan or shutting down the server according to the over-temperature information comprises: when the alarm level corresponding to the over-temperature information is high risk, the BMC module controls the server to shut down; when the alarm level corresponding to the over-temperature information is low risk, the BMC module controls the fan through the second PWM interface and the second TACH interface; when the alarm level corresponding to the over-temperature information is high risk, the CPLD module controls the server to shut down; and when the alarm level corresponding to the over-temperature information is low risk, the CPLD module controls the fan through the first PWM interface and the first TACH interface.

[0008] Further, the step of controlling the fan by the BMC module through the second PWM interface and the second TACH interface comprises: the BMC module sends a fan control signal to the CPLD module through the second PWM interface and the second TACH interface, so that the CPLD module outputs the fan control signal to the fan through the first PWM interface and the first TACH interface, to control the fan speed.

[0009] Further, the CPLD module comprises a PWM control module, which, when the alarm level corresponding to the over-temperature information is low risk, outputs a PWM fan control signal with a duty cycle of 70% by default, or outputs a PWM fan control signal with a matching set duty cycle according to different temperature intervals at low risk; and when the alarm level corresponding to the over-temperature information is high risk, outputs a PWM fan control signal with a duty cycle of 100%.

[0010] Further, after the step of transmitting, by the BMC module, the ACTIVE signal to the CPLD module through the first GPIO interface, the method further comprises: the CPLD module determines the working state of the BMC module according to the state of the ACTIVE signal; when the ACTIVE signal indicates that the BMC module is working normally, the CPLD module switches the signal interface of the fan to be controlled by the BMC module; and when the ACTIVE signal indicates that the BMC module is working abnormally, the CPLD module switches the signal interface of the fan to be controlled by the internal PWM control module.

[0011] Further, when the ACTIVE signal is a high-level signal, it indicates that the BMC module is working normally; and when the ACTIVE signal is a low-level signal, it indicates that the BMC module is working abnormally.

[0012] Further, the temperature information collected by the temperature sensor on the server mainboard comprises temperature information corresponding to a plurality of preset key point positions on the mainboard.

[0013] In a second aspect, the application further provides a fan speed control system based on a CPLD and a BMC, comprising: a CPLD module, a BMC module, and a cooling fan; wherein the CPLD module is connected with the cooling fan through a first PWM interface and a first TACH interface; the BMC module is connected with the CPLD module through a second PWM interface, a second TACH interface, a first GPIO interface, and an over-temperature information interface; the BMC module is further connected with a temperature sensor on a server mainboard through an I2C interface; the BMC module is further connected with a CPU through a second GPIO interface; the CPLD module is connected with the CPU through a third GPIO interface; the BMC module is configured to transmit an ACTIVE signal representing whether the BMC module is normally running to the CPLD module through the first GPIO interface; when the ACTIVE signal represents that the BMC module is normally working, the BMC module is further configured to read temperature information collected by the temperature sensor on the server mainboard through the I2C interface, and monitor and control the speed of the cooling fan according to the read temperature information through the second PWM interface and the second TACH interface; the BMC module is further configured to receive first over-temperature information sent by the CPU through the second GPIO interface, monitor and record the first over-temperature information for user maintenance and viewing, send the first over-temperature information to the CPLD module through the over-temperature information interface, and perform fan control or shutdown control according to the first over-temperature information; and the CPLD module is configured to receive the first over-temperature information reported by the CPU through the third GPIO interface when the ACTIVE signal represents that the BMC module is working abnormally, perform corresponding speed control on the cooling fan through the first PWM interface and the first TACH interface according to the first over-temperature information, or perform server shutdown control.

[0014] Further, the system further comprises: a power regulator module; the CPLD module is connected with the power regulator module through the third GPIO interface; the CPLD module is further configured to collect second over-temperature information sent by the power regulator module, and send the second over-temperature information to the BMC module; when the ACTIVE signal represents that the BMC module is normally working, the BMC module is further configured to perform fan control or shutdown control according to the second over-temperature information; and when the ACTIVE signal represents that the BMC module is working abnormally, the CPLD module is further configured to perform fan control or shutdown control according to the second over-temperature information.

[0015] The application provides a fan rotating speed control method and system based on a CPLD and a BMC. The application provides a fan rotating speed control method and system based on a CPLD and a BMC. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the application, the drawings needed in the specific embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0017] Figure 1 A structural diagram of a fan rotating speed control system based on a CPLD and a BMC provided by an embodiment of the application;

[0018] Figure 2 A flow chart of a fan speed control method based on CPLD and BMC provided by an embodiment of the present application is shown in the figure.

[0019] Figure 3 A structural diagram of another fan speed control system based on CPLD and BMC provided by an embodiment of the present application is shown in the figure.

[0020] Figure 4 A structural diagram of another fan speed control system based on CPLD and BMC provided by an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0021] The technical solutions of the present application will be described in detail below with reference to the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0022] The existing server cooling design method is to control the cooling fan directly according to the data read from the internal temperature sensor of the server by the BMC module. However, in the long-term operation of the system, the BMC module may be abnormal and invalid, and cannot control the cooling fan. The cooling fan cannot reach the expected state, resulting in a catastrophic event of the server motherboard, and there is a great security risk.

[0023] Therefore, the embodiments of the present application provide a fan speed control method based on CPLD (Complex Programmable Logic Device) and BMC (Baseboard Management Controller) to solve the foregoing problems in the prior art. In order to facilitate the understanding of the embodiments, first, a method disclosed by the embodiments of the present application is described in detail.

[0024] The embodiments of the present application provide a fan speed control method based on CPLD and BMC. The method is applied to a fan speed control system based on CPLD and BMC. Referring to Figure 1As shown, the system comprises: a CPLD module 11, a BMC module 12, a cooling fan 13; wherein the CPLD module 11 is connected with the cooling fan 13 through a first PWM interface (such as PWM1 in the figure), a first TACH interface (such as TACH1 in the figure); the BMC module 12 is connected with the CPLD module 11 through a second PWM interface (such as PWM2 in the figure), a second TACH interface (such as TACH2 in the figure), a first GPIO interface (such as GPIO1 in the figure), an over-temperature information interface; the BMC module 12 is further connected with a temperature sensor 14 on a server mainboard through an I2C interface; the BMC module 12 is further connected with a CPU 15 through a second GPIO interface (such as GPIO2 in the figure); the CPLD module 11 is further connected with the CPU 15 through a third GPIO interface (such as GPIO3 in the figure); see Figure 2 As shown in the flowchart of the fan speed control method based on the CPLD and the BMC, the method comprises the following steps:

[0025] In step S202, the BMC module transmits an ACTIVE signal to the CPLD module through the first GPIO interface, the ACTIVE signal being used to represent whether the BMC module is normally running;

[0026] The above ACTIVE signal is represented by two different digital identifiers or character identifiers, representing normal working and abnormal working of the BMC module. When the ACTIVE signal is a first identifier, it represents normal working of the BMC module; when the ACTIVE signal is a second identifier, it represents abnormal working of the BMC module. The first identifier and the second identifier can be different numbers or characters, such as 1 and 0 respectively representing normal working and abnormal working; or Y and N respectively representing normal working and abnormal working, etc.

[0027] In step S204, when the ACTIVE signal represents normal working of the BMC module, the BMC module reads temperature information collected by the temperature sensor on the server mainboard through the I2C interface, and monitors and controls the speed of the cooling fan according to the read temperature information through the second PWM interface and the second TACH interface; the BMC module further receives first over-temperature information sent by the CPU through the second GPIO interface, monitors and records the first over-temperature information for user maintenance and viewing, and sends the first over-temperature information to the CPLD module through the over-temperature information interface, and controls the fan or the shutdown according to the first over-temperature information;

[0028] The above temperature sensor on the server mainboard is used to collect temperature information of a plurality of preset key point positions on the mainboard in real time, that is, temperature information of each module inside the server.

[0029] The CPU sends first over-temperature information to the BMC module to make the BMC module make a decision, such as fan control or shutdown control according to the first over-temperature information, when judging that an over-temperature event occurs according to temperature information corresponding to a plurality of preset key point positions. The BMC module sends the first over-temperature information to the CPLD module to facilitate fan control or shutdown control through the CPLD module when the BMC module itself is abnormal, that is, the following steps:

[0030] In step S206, when the ACTIVE signal indicates that the BMC module is abnormal, the CPLD module receives the first over-temperature information reported by the CPU through the third GPIO interface, and performs corresponding speed control on the cooling fan through the first PWM interface and the first TACH interface according to the first over-temperature information, or performs server shutdown control.

[0031] The fan speed control method based on the cooperation of the BMC and the CPLD provided in the embodiments of the present application controls the fan through the cooperation of the BMC module and the CPLD module, avoids the situation that the cooling fan cannot reach the expected state due to the fact that the cooling fan speed cannot be normally controlled when the BMC module is suddenly abnormal, and causes a catastrophic event of the server mainboard, thereby improving the reliability and safety of the server product.

[0032] The embodiments of the present application also provide another fan speed control method based on the cooperation of the BMC and the CPLD, which is implemented based on the above-mentioned embodiment, and mainly describes a new system structure and the corresponding control method.

[0033] Referring to Figure 3 The system further includes a power regulator module 16, and the CPLD module 11 is connected with the power regulator module 16 through a third GPIO interface. The power regulator module 16 is a digital power controller for supplying power to the CPU, and includes a voltage regulator for the memory and the CPU, and has a sensor inside to detect temperature, voltage, current and other information.

[0034] The method further includes that the CPLD module collects second over-temperature information sent by the power regulator module and sends the second over-temperature information to the BMC module; when the ACTIVE signal indicates that the BMC module is normal, the BMC module performs fan control or shutdown control according to the second over-temperature information; and when the ACTIVE signal indicates that the BMC module is abnormal, the CPLD module performs fan control or shutdown control according to the second over-temperature information.

[0035] Further, the first over-temperature information and the second over-temperature information correspond to alarm levels respectively; the steps of controlling the fan or shutting down the server by the BMC module according to the over-temperature information include: when the alarm level corresponding to the over-temperature information is high risk, the BMC module controls the server to shut down; when the alarm level corresponding to the over-temperature information is low risk, the BMC module performs corresponding speed control on the cooling fan through the second PWM interface and the second TACH interface; when the alarm level corresponding to the over-temperature information is high risk, the CPLD module controls the server to shut down; and when the alarm level corresponding to the over-temperature information is low risk, the CPLD module performs corresponding speed control on the cooling fan through the first PWM interface and the first TACH interface.

[0036] It should be noted that the alarm level can be determined according to the size relationship between the detected temperature and the preset temperature threshold, for example, if the detected temperature is greater than the preset temperature threshold, the alarm level is determined to be high risk, and if the detected temperature is less than or equal to the preset temperature threshold, the alarm level is determined to be low risk. In the low-risk temperature range, different temperature levels can be divided to further refine the fan control mode.

[0037] Through the above control according to different risk levels, the server working environment temperature control can be more reasonably and accurately realized to maintain the high-performance operation of the server.

[0038] Further, the steps of performing corresponding speed control on the cooling fan by the BMC module through the second PWM interface and the second TACH interface include: the BMC module sends a fan control signal to the CPLD module through the second PWM interface and the second TACH interface, so that the CPLD module outputs the fan control signal to the cooling fan through the first PWM interface and the first TACH interface to control the fan speed. The CPLD module includes a PWM control module, which outputs a PWM fan control signal with a duty cycle of 70% by default when the alarm level corresponding to the over-temperature information is low risk, or outputs a PWM fan control signal with a matching set duty cycle according to different temperature level intervals under low risk; and outputs a PWM fan control signal with a duty cycle of 100% when the alarm level corresponding to the over-temperature information is high risk, to realize accurate fan speed control.

[0039] Further, after the step of transmitting, by the BMC module, the ACTIVE signal to the CPLD module through the first GPIO interface, the ACTIVE signal is used to represent whether the BMC module is in normal operation, the CPLD module judges the working state of the BMC module according to the state of the ACTIVE signal, when the ACTIVE signal represents that the BMC module is in normal operation, the signal interface of the cooling fan is switched to be controlled by the BMC module; when the ACTIVE signal represents that the BMC module is in abnormal operation, the signal interface of the cooling fan is switched to be controlled by the internal PWM control module.

[0040] The embodiment of the application is based on a Feiteng S5000C server mainboard, adopts a Feiteng E2000S BMC management chip, and the CPLD module adopts an EF3L90CG400B, which is used for signal level conversion so that the signals can be normally communicated before each chip, and is used for controlling the power-on sequence and power control of the server mainboard, and realizes specific logic functions according to requirements, and has the characteristics of instantaneous power-on, non-volatile storage, I / O counting and the like; the voltage regulator adopts an RAA229126, supports an SMBUS voltage regulation function, has zero-delay synthesized current control, and has high-precision current sensing and accurate overcurrent protection functions.

[0041] The fan speed control method based on the CPLD and the BMC provided by the embodiment of the application mainly comprises a CPLD module, a BMC module, a power regulator module and a cooling fan, wherein the BMC module has a PWM and a TACH interface, which are used to adjust and detect the speed of the cooling fan and are connected to the CPLD; the BMC module reads the mainboard temperature sensor information through an I2C interface, and also receives memory and CPU over-temperature alarm information through a GPIO interface, if an over-temperature event occurs, the BMC module reports the over-temperature information to the CPLD and is responsible for cooling fan speed regulation; the BMC module also has an ACTIVE signal, which is used to represent that the BMC system is in normal operation and is connected to the CPLD; the CPLD module comprises a PWM control module; the CPLD module is responsible for collecting over-temperature information reported by the CPU, the power regulator module and the BMC module, and synchronizing the information to the BMC module for cooling fan speed regulation; whether the BMC module is in normal operation is judged through the ACTIVE signal of the BMC module, if the BMC module is in normal operation, the mainboard fan is controlled by the BMC module, and if the BMC module is in abnormal operation, the CPLD module takes over the fan control.

[0042] In the embodiment of the application, the BMC module and the CPLD module cooperatively control the fan, so that when the BMC module suddenly abnormally operates, the cooling fan speed cannot be normally controlled, the cooling fan cannot reach the expected state, and a catastrophic event occurs on the server mainboard, the reliability and safety of the server product are improved.

[0043] Based on the above method embodiment, the present application embodiment also provides a fan speed control system based on CPLD and BMC, see Figure 1 As shown, the system includes: a CPLD module 11, a BMC module 12, and a cooling fan 13; wherein the CPLD module 11 is connected to the cooling fan 13 through a first PWM interface and a first TACH interface; the BMC module 12 is connected to the CPLD module 11 through a second PWM interface, a second TACH interface, a first GPIO interface, and an over-temperature information interface; the BMC module 12 is also connected to a temperature sensor 14 on a server motherboard through an I2C interface; the BMC module 12 is also connected to a CPU 15 through a second GPIO interface; and the CPLD module 11 is also connected to the CPU 15 through a third GPIO interface.

[0044] The BMC module 12 is configured to transmit an ACTIVE signal, indicating whether the BMC module is operating normally, to the CPLD module 11 via the first GPIO interface. When the ACTIVE signal indicates that the BMC module 12 is operating normally, the BMC module 12 is further configured to read temperature information collected by a temperature sensor 14 on the server motherboard via the I2C interface, and monitor and control the speed of the cooling fan 13 based on the read temperature information via the second PWM interface and the second TACH interface. The BMC module 12 is further configured to receive first over-temperature information sent by the CPU 15 via the second GPIO interface, monitor and record the first over-temperature information for user maintenance review, and transmit the first over-temperature information to the CPLD module 11 via the over-temperature information interface, and perform fan control or server shutdown control based on the first over-temperature information. When the ACTIVE signal indicates that the BMC module 12 is operating abnormally, the CPLD module 11 is configured to receive the first over-temperature information reported by the CPU 15 via the third GPIO interface, and perform corresponding speed control of the cooling fan 13 or server shutdown control based on the first over-temperature information via the first PWM interface and the first TACH interface.

[0045] See also Figure 3 As shown, the above-mentioned system also includes: a power regulator module 16; a CPLD module 11 is connected to the power regulator module 16 through a third GPIO interface; the CPLD module 11 is also used to collect the second over-temperature information sent by the power regulator module 16, and send the second over-temperature information to the BMC module 12; when the ACTIVE signal indicates that the BMC module is working normally, the BMC module 12 is also used to perform fan control or shutdown control according to the second over-temperature information; when the ACTIVE signal indicates that the BMC module is working abnormally, the CPLD module 11 is also used to perform fan control or shutdown control according to the second over-temperature information.

[0046] Figure 4The power regulator module 16 is shown to include an internal memory VR and a power VR. The over-temperature information transmission line is represented by a thick line in the figure. The specific working process can refer to the foregoing method embodiments, and will not be described here.

[0047] The system provided by the embodiments of the present application has the same implementation principle and generated technical effects as the foregoing method embodiments. For brief description, the system embodiments not mentioned in the foregoing method embodiments can refer to the corresponding content in the foregoing method embodiments.

[0048] In the description of the present application, it should be noted that the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0049] Finally, it should be pointed out that: the above-described embodiments are only specific implementations of the present application, used to describe the technical solutions of the present application, and not to limit them. The protection scope of the present application is not limited to this. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily think of changes to the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features, within the technical range disclosed by the present application. The modifications, changes or replacements do not make the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A fan speed control method based on CPLD cooperation with BMC, characterized in that, The method is applied to a fan speed control system based on a CPLD and a BMC, and the system comprises a CPLD module, a BMC module and a cooling fan; the CPLD module is connected with the cooling fan through a first PWM interface and a first TACH interface; the BMC module is connected with the CPLD module through a second PWM interface, a second TACH interface, a first GPIO interface and an over-temperature information interface; the BMC module is further connected with a temperature sensor on a server mainboard through an I2C interface; the BMC module is further connected with a CPU through a second GPIO interface; the CPLD module is connected with the CPU through a third GPIO interface; and the method comprises the following steps: The BMC module transmits an ACTIVE signal to the CPLD module through the first GPIO interface, the ACTIVE signal being used to represent whether the BMC module is normally running; When the ACTIVE signal represents that the BMC module is normally running, the BMC module reads temperature information collected by the temperature sensor on the server mainboard through the I2C interface, and monitors and controls the speed of the cooling fan according to the read temperature information through the second PWM interface and the second TACH interface; the BMC module further receives first over-temperature information sent by the CPU through the second GPIO interface, monitors and records the first over-temperature information for user maintenance and viewing, and sends the first over-temperature information to the CPLD module through the over-temperature information interface, and controls the fan or performs shutdown control according to the first over-temperature information; When the ACTIVE signal represents that the BMC module is abnormally running, the CPLD module receives the first over-temperature information reported by the CPU through the third GPIO interface, and performs corresponding speed control on the cooling fan or performs server shutdown control according to the first over-temperature information through the first PWM interface and the first TACH interface; The system further comprises a power regulator module; the CPLD module is connected with the power regulator module through the third GPIO interface; and the method further comprises the following steps: the CPLD module collects second over-temperature information sent by the power regulator module, and sends the second over-temperature information to the BMC module; when the ACTIVE signal represents that the BMC module is normally running, the BMC module performs fan control or shutdown control according to the second over-temperature information; and when the ACTIVE signal represents that the BMC module is abnormally running, the CPLD module performs fan control or shutdown control according to the second over-temperature information. The first over-temperature information and the second over-temperature information correspond to alarm levels; the step of controlling the fan or shutting down the server according to the over-temperature information comprises: when the alarm level corresponding to the over-temperature information is high risk, the BMC module controls the server to shut down; when the alarm level corresponding to the over-temperature information is low risk, the BMC module controls the speed of the cooling fan through the second PWM interface and the second TACH interface; when the alarm level corresponding to the over-temperature information is high risk, the CPLD module controls the server to shut down; and when the alarm level corresponding to the over-temperature information is low risk, the CPLD module controls the speed of the cooling fan through the first PWM interface and the first TACH interface.

2. The method of claim 1, wherein, The step of controlling the speed of the cooling fan by the BMC module through the second PWM interface and the second TACH interface comprises: The BMC module sends a fan control signal to the CPLD module through the second PWM interface and the second TACH interface, so that the CPLD module outputs a fan control signal to the cooling fan through the first PWM interface and the first TACH interface, to control the speed of the fan.

3. The method of claim 2, wherein, The CPLD module comprises a PWM control module, which, when the alarm level corresponding to the over-temperature information is low risk, outputs a PWM fan control signal with a duty cycle of 70% by default, or outputs a PWM fan control signal with a matching set duty cycle according to different temperature interval levels under low risk; and when the alarm level corresponding to the over-temperature information is high risk, outputs a PWM fan control signal with a duty cycle of 100%.

4. The method of claim 3, wherein, After the step of transmitting, by the BMC module through the first GPIO interface, an ACTIVE signal representing whether the BMC module is normally running to the CPLD module, the method further comprises: The CPLD module determines the working state of the BMC module according to the state of the ACTIVE signal, and when the ACTIVE signal represents that the BMC module is normally working, switches the signal interface of the cooling fan to be controlled by the BMC module; and when the ACTIVE signal represents that the BMC module is abnormally working, switches the signal interface of the cooling fan to be controlled by the internal PWM control module.

5. The method of claim 1, wherein, When the ACTIVE signal is a high-level signal, it represents that the BMC module is normally working; and when the ACTIVE signal is a low-level signal, it represents that the BMC module is abnormally working.

6. The method of claim 1, wherein, The temperature information collected by the temperature sensor on the server mainboard comprises temperature information corresponding to a plurality of preset key point positions on the mainboard.

7. A fan speed control system based on CPLD cooperated with BMC, characterized in that, The system comprises a CPLD module, a BMC module and a cooling fan; the CPLD module is connected with the cooling fan through a first PWM interface and a first TACH interface; the BMC module is connected with the CPLD module through a second PWM interface, a second TACH interface, a first GPIO interface and an over-temperature information interface; the BMC module is further connected with a temperature sensor on a server mainboard through an I2C interface; the BMC module is further connected with a CPU through a second GPIO interface; the CPLD module is connected with the CPU through a third GPIO interface; The BMC module is configured to transmit an ACTIVE signal representing whether the BMC module is in normal operation to the CPLD module through the first GPIO interface; The BMC module is further configured to read temperature information collected by the temperature sensor on the server mainboard through the I2C interface when the ACTIVE signal represents that the BMC module is in normal operation, and monitor and control the rotating speed of the cooling fan through the second PWM interface and the second TACH interface according to the read temperature information; The BMC module is further configured to receive first over-temperature information sent by the CPU through the second GPIO interface, monitor and record the first over-temperature information for user maintenance and viewing, send the first over-temperature information to the CPLD module through the over-temperature information interface, and perform fan control or shutdown control according to the first over-temperature information; The CPLD module is configured to receive the first over-temperature information reported by the CPU through the third GPIO interface when the ACTIVE signal represents that the BMC module is in abnormal operation, and perform corresponding speed control on the cooling fan through the first PWM interface and the first TACH interface according to the first over-temperature information, or perform server shutdown control; The system further comprises a power regulator module; the CPLD module is connected with the power regulator module through the third GPIO interface; the CPLD module is further configured to collect second over-temperature information sent by the power regulator module and send the second over-temperature information to the BMC module; when the ACTIVE signal represents that the BMC module is in normal operation, the BMC module is further configured to perform fan control or shutdown control according to the second over-temperature information; when the ACTIVE signal represents that the BMC module is in abnormal operation, the CPLD module is further configured to perform fan control or shutdown control according to the second over-temperature information. The first over-temperature information and the second over-temperature information both correspond to alarm levels; the step of performing fan control or shutdown control according to the over-temperature information comprises: when the alarm level corresponding to the over-temperature information is high risk, the BMC module controls the server to shut down; when the alarm level corresponding to the over-temperature information is low risk, the BMC module performs corresponding speed control on the cooling fan through the second PWM interface and the second TACH interface; when the alarm level corresponding to the over-temperature information is high risk, the CPLD module controls the server to shut down; and when the alarm level corresponding to the over-temperature information is low risk, the CPLD module performs corresponding speed control on the cooling fan through the first PWM interface and the first TACH interface.

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