TWI385528B - Arbitration device for system bus - Google Patents

Description

Arbitration device of system bus

The present invention relates to an arbitration apparatus, and more particularly to an arbitration apparatus suitable for arbitrating the priority order of a bus of a multi-layer system.

At present, the common system bus arbitration devices use a single arbitration algorithm, such as IBM's CoreConnect bus structure and ARM's AMBA bus structure. The products published are all using the highest priority algorithm. (First priority algorithm) is the algorithm for its arbitration device.

However, this kind of arbitration algorithm limited to a single algorithm as a different application will make the resources of the bus bar not be properly utilized, thus affecting the overall system performance. For example, in today's mobile phones, because There are other audio and video functions, such as: music playback, photo taking, photo/video browsing and other different functions. When using the highest priority algorithm as the arbitration algorithm of the system bus in the mobile phone, the internal related functional components A high-low priority will be preset in advance, because the most important function of the mobile phone is to make or receive calls, so it is assumed that the baseband device in the mobile phone has the highest priority, color digital signal processing ( The CDSP) device is the second, the MP3 decoding device is again equal. However, when the user wants to use the mobile phone to play music, the timing of the MP3 decoding device using the system bus may cause the system bus to be obtained because of its lower priority. There are fewer opportunities, and the process of music playback is not smooth.

In addition, when the system bus arbitration device is applied to the multi-layer system bus system, most of the external devices are accessed through a dedicated system bus, regardless of the design method, each external device has a dedicated system convergence. The access to any slave device (Slave), or each slave device has a dedicated system bus for access, can not effectively achieve the purpose of the shared system bus, so each external device access When a slave device is accessed from only one path, even if there are other idle bus bars, the external device cannot be used because the idle bus bar does not belong to its exclusive system bus, which may result in The number of system bus bars needs to increase with the number of external devices, which in turn increases costs.

Therefore, in summary of the above, the conventional design has the following shortcomings:

1. It is impossible to effectively share the system bus: the conventional design has no effective arbitration mechanism. Therefore, it is necessary to design a dedicated system bus for use by each external device or slave device. The arbitration method is when the system bus is busy. Re-arbitration, and when the system bus is idle, the system bus usage right is set to the external device to be accessed; this will cause the number of system bus bars to increase with the number of external devices or from the potato device. Increasing costs;

Second, it is easy to cause the same device to occupy the system bus for a long time: When a conventional design performs arbitration by a specific algorithm, it is easy to cause some external devices to easily obtain the right to use the system bus due to their transmission characteristics. Time occupies the system bus, similarly, some external devices can not use the system bus for a long time, and the resource allocation of the system bus is uneven, which affects the system transmission efficiency;

Third, it is not easy to expand and apply to different products: the conventional design uses a specific arbitration algorithm built in an arbitration device, it is difficult to expand the application of a system bus, because different applications are possible This will make the specific arbitration algorithm ineffective, resulting in wasted resources of the bus or a long transmission delay, which will make the system transmission performance decline.

Therefore, how to effectively develop an arbitration device for a system bus has always been one of the issues of great concern to the industry.

Accordingly, it is an object of the present invention to provide an arbitration apparatus for a system bus that is adapted to arbitrate a plurality of external devices requesting the use of a plurality of system busses to access another device, comprising: a first arbitration unit, Including m arbitration modules, and each arbitration module is electrically connected to n external devices, and receives requests from the devices to access the system bus bar for arbitration to output an arbitration result; a second arbitration unit, connected And receiving, by the first arbitration unit, arbitration results of all arbitration modules, and arbitrating the arbitration results to output a priority order; and an output processing unit receiving the priority sequence and determining the current system bus usage State, when all system bus bars are idle, the output processing unit sets the usage right of one of the system bus bars to the external device with the highest priority order, when part of the system bus bar is busy and part of the system is converged When the row is idle, the output processing unit will be in the idle state of the system bus according to the priority order By weight can be set to the external device to access.

The effect of the invention is:

1. The system bus can be effectively shared: the order of the currently requested device is arranged according to the priority order, and then the output processing unit determines the current state of use of the system bus and sets the usage right of the system bus to the outside of the request. The device, therefore, can be accessed by the next highest priority external device when the external device with the highest priority cannot be accessed;

Second, effectively improve the efficiency of the system bus: by means of the two-stage arbitration, the opportunity for each device to obtain access to the system bus is more even, to avoid the bandwidth of the system bus for the same device for a long time;

3. It is easy to expand and apply to different products: by providing a combination of multiple arbitration algorithms by externally input control codes, the user can dynamically set appropriate arbitration algorithm combinations according to different usage modes, thereby making the present invention Can be more widely used in different products.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments of the invention.

First preferred embodiment

Referring to Figure 1, a first preferred embodiment of the arbitration apparatus for a system bus of the present invention is adapted to arbitrate a priority order in which a plurality of external devices 901-916 request to use a two-system bus 8 to access another device, including: A first arbitration unit 11, a second arbitration unit 12, a control unit 13, and an output processing unit 14.

The first arbitration unit 11 includes four arbitration modules, which are a first arbitration module 111, a second arbitration module 112, a third arbitration module 113, and a fourth arbitration module 114, and each The arbitration modules 111~114 all have a built-in fixed priority algorithm, a Round-Robin algorithm, a First-come-first-service algorithm, and a random access memory. Four different arbitration algorithms, such as a random access algorithm, each of the arbitration modules 111-114 receives a binary control signal transmitted by the control unit 13 to set an arbitration within the corresponding arbitration module. Algorithm, for example, when the control signal is 11, the arbitration module will use the advanced first service algorithm as the arbitration algorithm.

Each arbitration module 111-114 is connected to four external devices, and performs arbitration of the usage rights of the system bus 8 according to the set arbitration algorithm, and finally outputs an arbitration that determines which external device can obtain the right to use the bus. result. For example, the first arbitration module 111 connects the device 901 to the device 904 and outputs an arbitration result A. Similarly, the second arbitration module 112 connects the device 905 to the device 908 and outputs an arbitration result B and a third arbitration module. 113 respectively connects the device 909 to the device 912 and outputs an arbitration result C. The fourth arbitration module 114 connects the device 913 to the device 916 and outputs an arbitration result D.

The second arbitration unit 12 also has built in four arbitration algorithms, such as fixed priority, average cycle, advanced first service, and random access, and receives a binary control signal transmitted by the control unit 13 to set The arbitration algorithm corresponding to the second arbitration unit 12, for example, when the control signal is 11, the second arbitration unit 12 will use the advanced service algorithm as the arbitration algorithm.

The second arbitration unit 12 receives the arbitration results A~D outputted by each of the arbitration modules 111-114 of the first arbitration unit 11, and performs arbitration of the usage rights of the system bus 8 according to the set arbitration algorithm, and finally outputs one. The priority order is assigned to the output processing unit 14, which represents the order in which the second arbitration unit 12 determines that all of the requesting external devices use the system bus.

The control unit 13 receives a tens control code input by an external input (eg, user input), and transmits the corresponding control code to each of the arbitration modules 111-114 and the first arbitration unit 11 In the second arbitration unit 12, for example, the zeroth and first bits of the control code are defined as the control signals of the second arbitration unit 12, and the control unit 13 transmits the two bits to the second arbitration unit. 12, the second arbitration unit 12 is adjusted to the corresponding arbitration algorithm, and the remaining eight bits are also defined as the control signals of the four arbitration modules 111-114, and the corresponding two-bit control signals are transmitted by the control unit to In the corresponding arbitration module, the arbitration algorithm in each arbitration module 111-114 is adjusted.

For example, it is assumed that the control code is sequentially represented by the control signal of the first arbitration module 111, the control signal of the second arbitration module 112, the control signal of the third arbitration module 113, and the The control signal of the fourth arbitration module 114 and the control signal of the second arbitration unit 12, and each of the control signals has a fixed priority algorithm when the two bits are 00, and the average cyclic calculation when the two bits of the control signal are 01. In the method, the two bits of the control signal are 10 hours for the advanced first service algorithm, and the two bits of the control signal are 11 hours for the random access algorithm. When the user inputs the control code 00_0110_1011, it represents the first The arbitration module 111 selects the fixed priority algorithm as the arbitration algorithm, the second arbitration module 112 selects the average loop algorithm as the arbitration algorithm, and the third arbitration module 113 selects the advanced first service algorithm as the arbitration algorithm, and the fourth The arbitration module 114 selects the advanced first service algorithm as the arbitration algorithm, and the second arbitration unit 12 selects the random access algorithm as the arbitration algorithm.

Since the arbitration algorithms of each of the arbitration modules 111-114 and the second arbitration unit 12 can be externally controlled, it is assumed that when a music playing function is required in a mobile phone, the externally set control code can be used. The arbitration module 111~114 connected to the music playback function related device switches to an appropriate arbitration algorithm (or further switches the second arbitration unit 12 to an appropriate arbitration algorithm), such as a Round-Robin algorithm. ), so that the MP3 decoding device can have a relatively equal opportunity to obtain the right to use the system bus 8 with other devices, thereby improving the performance of the music playing mode, and when the mobile phone returns to the call mode, switching back to the highest priority calculation. In order to maintain the smoothness of the call, the system bus arbitration algorithm that dynamically adjusts the mobile phone can effectively balance the call function with other multimedia functions.

Taking this embodiment as an example, in the case of 16 external devices, since the number of bits corresponding to the control code is 10 bits, there are a total of 1024 different arbitration algorithms in the group, when there is an arbitration device of the present invention. When the system convergence is applied to different products, the combination of arbitration algorithms can be dynamically adjusted according to the characteristics of different products, so that the transmission efficiency of the system bus can be effectively maintained without being changed by different product application characteristics. .

The output processing unit 14 includes a storage unit 141, a determiner 142, and a processor 143. The storage unit 141 is configured to sequentially store the identification name (ID) of the requesting external device and the device address that each external device wants to access according to the priority order of the output of the second arbitration unit 12; the determiner 142 is used to determine the current state of the system bus 8; the processor 143 determines the external device using each system bus according to the judgment result of the determiner 142. The determiner 142 determines the current status of the system bus 8 as follows:

1. When all system bus bars 8 are in an idle state: the processor 143 sets the usage right of one of the system bus bars to the external device having the highest priority order, and marks the address of the access device as using Medium state, and the use right of another system bus that is also idle is set to be used by an external device having the next highest priority order, and the address of the access device is marked as an in-use state;

2. When one of the system bus bars 8 is in a busy state, the processor 143 sequentially compares the access device addresses of the external devices with the access device bits of the external devices on the current system bus in accordance with the priority order. Address, when the comparison is equal, indicating that the device to be accessed by the external device is being accessed by other external devices, so the external devices in the next priority order are sequentially taken out and compared again until the comparison is not equal. And setting another system bus usage right in an idle state to the external device for access, and marking the address of the access device as an in-use state;

3. When all system bus bars 8 are busy: the processor 143 will clear the memory 141 and re-arbitrate.

An example of the processing of the output processing unit 14 is as follows: assuming that the external device 901 and the external device 915 make a request to use the system bus, the priority order after arbitration by the first and second arbitration units 11, 12 is the external device 915. Compared with the external device 901, in the output processing unit, the ID of the external device 915 and the device address (0010) to be accessed, the ID of the external device 901, and the device address to be accessed (0111) Stored in the storage unit 141 in sequence, when the determiner 142 determines that one of the system bus bars is performing the device access operation of the address (0010), the processor 143 takes the external storage from the storage unit 141 in accordance with the priority order. The device 915 and its access device address (0010) are compared with the device address being accessed on the system bus. When the comparison results are equal, the device indicating that the external device 915 is to be accessed is being used by the other device. The external device is accessed. Therefore, the processor 143 takes out the next external device 901 and its access device address (0111) in accordance with the priority order and compares them again. When the comparison result is not equal, the external device is indicated. The device to be accessed 901 is currently in an idle state and can be accessed by the external device 901. Therefore, the processor 143 sets the system bus usage right in the idle state to the external device 901 for access.

It should be noted that although the first embodiment is applied to the two system bus bars 8 as an example, it is not limited thereto.

Second preferred embodiment

Referring to FIG. 2, the second preferred embodiment of the present invention is similar to the first embodiment. The difference lies in the number of arbitration modules included in the first arbitration unit 11 and the number of external devices connected to each arbitration module.

In the second preferred embodiment of the present invention, the first arbitration unit 11 includes m arbitration modules, and each arbitration module has built in a plurality of different arbitration algorithms, wherein each arbitration module is connected to n. An external device and output an arbitration result. In addition, each arbitration module receives a transmission by the control unit 13 The bit control signal is used to set an arbitration algorithm corresponding to the arbitration module.

The second arbitration unit 12 also has built in P different arbitration algorithms, and respectively receives the arbitration results output by each arbitration module of the first arbitration unit 11 to output a priority sequence to the output processing unit. In addition, the second arbitration unit 12 receives a transmission by the control unit 13. The bit control signal is used to set an arbitration algorithm corresponding to the interior of the second arbitration unit 12.

The control unit 13 receives an externally input K-bit control code, and transmits the corresponding control code to each of the arbitration modules and the second arbitration unit 12 of the first arbitration unit 11, wherein the control code The number of bits K is calculated as follows:

According to the description of the second preferred embodiment, the system bus 8 arbitration apparatus of the present invention can internally implement a plurality of different arbitration algorithms, and at the same time, the first arbitration unit 11 can be caused by correspondingly adjusting the number of bits of the control code. The arbitration algorithm in each arbitration module and the second arbitration unit 12 can be dynamically adjusted.

In summary, the system bus arbitration device of the present invention has the following advantages:

1. Effectively sharing the system busbar: When the present invention is applied to a multi-layer system busbar system, since each external device has multiple paths for access, a dedicated system busbar is not required, and according to the second arbitration unit Priority order, which ranks the priority order of the device that is currently requesting, and then the output processing unit determines the current state of use of the system bus and sets the usage right of the system bus to the external device that allows the request, therefore, when When the highest priority external device cannot be accessed, it can still be accessed by the next highest priority external device, so the present invention can effectively achieve the purpose of sharing the bus bar;

Second, effectively improve the efficiency of the system bus: by means of the two-stage arbitration, each device has a more uniform access to the system bus access, thus avoiding the same device occupying the bandwidth of the system bus for a long time, and then Causing a situation in which the transmission efficiency of the system is degraded; and

3. It is easy to expand and apply to different products: the control unit receives externally input control codes to provide a combination of multiple arbitration algorithms, which allows the user to dynamically set appropriate arbitration algorithm combinations according to different usage modes. The invention can be applied more broadly to different products.

Therefore, the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

11‧‧‧First Arbitration Unit

111‧‧‧First Arbitration Module

112‧‧‧Second Arbitration Module

113‧‧‧ Third Arbitration Module

114‧‧‧fourth arbitration module

12‧‧‧Second Arbitration Unit

13‧‧‧Control unit

14‧‧‧Output processing unit

141‧‧‧Storage

142‧‧‧ judge

143‧‧‧ processor

8‧‧‧System Bus

901~916‧‧‧External device

1 is a block diagram of a first preferred embodiment of a system bus arbitration device of the present invention; and

Figure 2 is a block diagram of a second preferred embodiment of the system bus arbitration device of the present invention.

11. . . First arbitration unit

111. . . First arbitration module

112. . . Second arbitration module

113. . . Third arbitration module

114. . . Fourth arbitration module

12. . . Second arbitration unit

13. . . control unit

14. . . Output processing unit

141. . . Storage

142. . . Judger

143. . . processor

8. . . System bus

901~916. . . External device

Claims (8)

An arbitration device for a system bus is adapted to arbitrate a sequence in which a plurality of external devices request to use a plurality of system bus bars to access another device, comprising: a first arbitration unit, including a plurality of arbitration modules, and each The arbitration module is electrically connected to the plurality of external devices, and receives a request from the devices to access the system bus bar for arbitration to output an arbitration result; a second arbitration unit is coupled to the first arbitration unit and receives all arbitrations Arbitration result of the module, and arbitrating the arbitration results to output a priority order; and an output processing unit receiving the priority order and determining the current usage status of the system bus, when all system bus bars are idle In the state, the output processing unit sets the usage right of one of the system bus bars to the external device having the highest priority order. When the partial system bus is in a busy state and part of the system bus is idle, the output processing unit is prioritized. The order of rights sets the system bus usage rights in the idle state to be available for storage. An external device; the output processing unit sequentially stores the identification name of the requesting external device and the device address to be accessed by each external device according to the priority order; when the usage right of a system bus is set to When an external device is in use, the output processing unit marks the external device to perform an access device address in an in-use state; When part of the system bus is in a busy state and part of the system bus is idle, the output processing unit fetches the corresponding access device address of each external device according to the priority order, and the external device currently used on the system bus The access device addresses are compared. When the comparisons are equal, the external devices that take the next priority order are compared again, until the comparison is not equal, then the system bus usage right in the idle state is set to The external device accesses. The arbitration device of the system bus according to claim 1, wherein the output processing unit includes a determiner for determining a current state of use of the bus and a setting of at least one system according to the judgment result of the determiner. The processor of the right to use the bus. The arbitration device of the system bus according to claim 1, further comprising a control unit connected to the first arbitration unit and the second arbitration unit for dynamically adjusting presets to the first arbitration unit The arbitration mode of the second arbitration unit. The arbitration device of the system bus according to claim 3, wherein the control unit receives an externally input control code and transmits the corresponding control code to the first arbitration unit and the second arbitration unit. . According to the arbitration device of the system bus according to claim 1, wherein each arbitration module has a plurality of arbitration algorithms built therein, and the second arbitration unit also has a plurality of arbitration algorithms built in. Arbitration device for system bus according to item 5 of the patent application scope The method further includes a control unit connected to the first arbitration unit and the second arbitration unit for dynamically selecting an arbitration algorithm built in each arbitration module and the second arbitration unit. The arbitration device of the system bus according to claim 6, wherein the control unit receives an externally input control code and transmits the corresponding control code to each arbitration module and the second arbitration unit. . The arbitration device of the system bus according to claim 1, wherein when all system bus bars are busy, arbitration will be re-arbitrated.