Bus protocol

Abstract

A write-only data transfer protocol for peripheral component interface busses and a method for transferring data between source and destination communication units is provided. The method includes the source communication unit writing a buffer allocation request to the destination unit and, in response to the buffer allocation request, the destination communication unit allocating space within an associated buffer to receive the data to be sent. The method also includes the destination communication unit writing at least the location of the allocated buffer to the source communication unit and the source communication unit writing the data to be sent to the allocated buffer location.

1. A method for transferring data between source and destination communication units, the method comprising the steps of:
 a. the source communication unit writing a buffer allocation request to the destination communication unit;  
 b. in response to the buffer allocation request, the destination communication unit allocating space within an associated buffer to receive the data to be sent;  
 c. the destination communication unit writing at least the location of the allocated buffer to the source communication unit; and  
 d. the source communication unit writing the data to be sent to the allocated buffer location.  
 
     
     
       2. A method according to  claim 1  and wherein said step of writing a buffer allocation request includes the step of writing at least the address of said source communication unit and the size of the data to be transferred into a buffer allocation request register of said destination communication unit. 
     
     
       3. A method according to  claim 1  and wherein said second step of writing includes the step of writing at least the address of the allocated buffer and of the destination communication unit into a start of packet register in said source communication unit. 
     
     
       4. A method according to claim  3  and wherein said second step of writing includes  further comprising the step of:
 the destination communication unit writing at least thean address of thean allocated buffer and  of the destination communication unit into a start of packet register in said source communication unit.  
 
     
     
       5. A method according to  claim 1  and wherein said source and destination communication units are physically separate units. 
     
     
       6. A method according to  claim 1  wherein said steps of writing are performed by direct memory access transfer. 
     
     
       7. A method for transferring data between source and destination communication units, the method comprising the steps of:
 a. the source communication unit writing the data to be sent with an indication of the buffer location into which the destination communication unit should write the data to be sent.  
 
     
     
       8. A method according to  claim 7  wherein said step of writing is performed by direct memory access transfer. 
     
     
       9. A method for transferring data between source and destination communication units connected via a bus having a data line and an address line, the method comprising the steps of:
 a. the source communication unit writing the data to be sent on said data line and at least the address of said destination communication unit and the address of a buffer location within said destination communication unit on said address line.  
 
     
     
       10. A method according to  claim 9  wherein said step of writing is performed by direct memory access transfer. 
     
     
       11. A write-only data transfer protocol for peripheral component interface busses for transferring data between source and destination peripheral components, the method comprising the steps of:
 a. the source peripheral component writing a buffer allocation request to the destination unit  peripheral component;  
 b. in response to the buffer allocation request, the destination nation peripheral component allocating space within an associated buffer to receive the data to be sent;  
 c. the destination peripheral component writing at least the location of the allocated buffer to the source peripheral component; and  
 d. the source peripheral component writing the data to be sent to the allocated buffer location.  
 
     
     
       12. A method according to  claim 11  wherein said steps of writing are performed by direct memory access transfer. 
     
     
       13. A communications system comprising:
   a source communication unit comprising a source buffer;        a destination communication unit in communication with said source communication unit, and comprising a destination buffer;        wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit  ( i )  allocates a location within said destination buffer to receive the data to be sent from said source communication unit, and  ( ii )  provides at least the location of said destination buffer to said source communication unit, and        wherein said source communication unit provides the data to said destination buffer for storage at the location.     
     
     
       14. A communication system according to  claim 13 , wherein said source communication unit further comprises a first switching unit responsive to a first plurality of source nodes, and wherein said destination communication unit further comprises a second switching unit in communication with a second plurality of destination nodes. 
     
     
       15. A communication system according to  claim 14 , further comprising an address line and a data line, wherein the destination buffer allocation request by said source communication unit to said destination communication unit is provided on said address line, wherein said destination communication unit provides the location of said destination buffer to said source communication unit on said address line, and wherein said source communication unit provides the data to said destination buffer on said data line. 
     
     
       16. A communication system according to  claim 15 , wherein said destination communication unit provides ( i )  a start of the location of said destination buffer to said source communication unit on said address line, and  ( ii )  and an address of said source communication unit on the data line.   
     
     
       17. A communication system according to  claim 15 , wherein said source communication unit further comprises a source register, and wherein the destination buffer allocation request by said source communication unit to said destination communication unit comprises ( i )  an address of said source register,  ( ii )  an address of said second switching unit, and  ( iii )  an address of said first switching unit.   
     
     
       18. A communication system according to  claim 15 , wherein said source communication unit further comprises a source register, and wherein the destination buffer allocation request by said source communication unit to said destination communication unit comprises ( i )  a size of the data to be transferred and  ( i )  an address of said source buffer storing the data.   
     
     
       19. A communication system according to  claim 18 , wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit further provides the location of said destination buffer and an address of said source communication unit to a start of packet register in said source register. 
     
     
       20. A communication system according to  claim 15 , wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit further provides the location of said destination buffer and an address of said source communication unit to said source communication unit on said address line. 
     
     
       21. A communication system according to  claim 13 , wherein said destination communication unit further comprises a destination register, and wherein the destination buffer allocation request by said source communication unit to said destination communication unit is provided to said destination register. 
     
     
       22. A communication system according to  claim 13 , wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit further provides the location of said destination buffer and an address of said source communication unit to said source communication unit. 
     
     
       23. A communication system comprising:
   a source node;        a source communication unit in communication with said source node and comprising a source buffer;        a destination communication unit in communication with said source communication unit and comprising a destination buffer,        wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit  ( i )  allocates a location within said destination buffer to receive the data to be sent from said source communication unit, and  ( ii )  provides at least the location of said destination buffer to said source communication unit, and        wherein said source communication unit provides the data to said destination buffer for storage at the location; and        a destination node in communication with said destination communication unit.     
     
     
       24. A communication system according to  claim 23 , wherein said source communication unit further comprises a first switching unit responsive to a first plurality of source nodes, and wherein said destination communication unit further comprises a second switching unit in communication with a second plurality of destination nodes. 
     
     
       25. A communication system according to  claim 24 , further comprising an address line and a data line, wherein the destination buffer allocation request by said source communication unit to said destination communication unit is provided on said address line, wherein said destination communication unit provides the location of said destination buffer to said source communication unit on said address line, and wherein said source communication unit provides the data to said destination buffer on said data line. 
     
     
       26. A communication system according to  claim 25 , wherein said destination communication unit provides ( i )  a start of the location of said destination buffer to said source communication unit on said address line, and  ( ii )  an address of said source communication unit on said data line.   
     
     
       27. A communication system according to  claim 25 , wherein said source communication unit further comprises a source register, wherein the destination buffer allocation request by said source communication unit to said destination communication unit comprises ( i )  an address of said source register,  ( ii )  an address of said second switching unit, and  ( iii )  an address of said first switching unit.   
     
     
       28. A communication system according to  claim 27 , wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit further provides the location of said destination buffer and an address of said source communication unit to a start of packet register in said source register. 
     
     
       29. A communication system according to  claim 25 , wherein said source communication unit further comprises a source register, and wherein the destination buffer allocation request by said source communication unit to said destination communication unit comprises a size of the data to be transferred and an address of said source buffer storing the data. 
     
     
       30. A communication system according to  claim 25 , wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit further provides the location of said destination buffer and an address of said source communication unit to said source communication unit on said address line. 
     
     
       31. A communication system according to  claim 23 , wherein said destination communication unit further comprises a destination register, and wherein the destination buffer allocation request by said source communication unit to said destination communication unit is provided to said destination register. 
     
     
       32. A communication system according to  claim 23 , wherein, in response to a destination buffer allocation request by said source communication unit to said destination communication unit, said destination communication unit further provides the location of said destination buffer and an address of said source communication unit to said source communication unit. 
     
     
       33. A communications system comprising:
   source communication means for transmitting and receiving data comprising source buffer means for storing data;        destination communication means for transmitting and receiving data in communication with said source communication means and comprising destination buffer means for storing data;        wherein, in response to a destination buffer means allocation request by said source communication means to said destination communication means, said destination communication means  ( i )  allocates a location within said destination buffer means to receive the data to be sent from said source communication means, and  ( ii )  provides at least the location of said destination buffer means to said source communication means, and        wherein said source communication means provides the data to said destination buffer means for storage at the location.     
     
     
       34. A communication system according to  claim 33 , wherein said source communication means further comprises first switching means for routing data responsive to a first plurality of source nodes, and wherein said destination communication means further comprises second switching means for routing data in communication with a second plurality of destination nodes. 
     
     
       35. A communication system according to  claim 34 , further comprising an address line means for transferring data and a data line means for transferring data, wherein the destination buffer means allocation request by said source communication means to said destination communication means is provided on said address line means, wherein said destination communication means provides the location of said destination buffer means to said source communication means on said address line means, and wherein said source communication means provides the data to said destination buffer means on said data line means. 
     
     
       36. A communication system according to  claim 35 , wherein said destination communication means provides ( i )  a start of the location of said destination buffer means to said source communication means on said address line means and  ( ii )  an address of said source communication means on said data line means.   
     
     
       37. A communication system according to  claim 35 , wherein said source communication means further comprises source register means for storing data, wherein the destination buffer means allocation request by said source communication means to said destination communication means comprises ( i )  an address of said source register means,  ( ii )  an address of said second switching means, and  ( iii )  an address of said first switching means on said address line means.   
     
     
       38. A communication system according to  claim 37 , wherein, in response to a destination buffer means allocation request by said source communication means to said destination communication means, said destination communication means further provides the location of said destination buffer means and an address of said source communication means to a start of packet register means in said source register means. 
     
     
       39. A communication system according to  claim 35 , wherein said source communication means further comprises source register means for storing data, wherein the destination buffer means allocation request by said source communication means to said destination communication means comprises a size of the data to be transferred and an address of said source buffer means storing the data on said data line means. 
     
     
       40. A communication system according to  claim 35 , wherein, in response to a destination buffer means allocation request by said source communication means to said destination communication means, said destination communication means further provides the location of said destination buffer means and an address of said source communication means to said source communication means. 
     
     
       41. A communication system according to  claim 33 , wherein in response to a destination buffer means allocation request by said source communication means to said destination communication means; said destination communication means further provides the location of said destination buffer means and an address of said source communication means to said source communication means. 
     
     
       42. A communication system according to  claim 33 , wherein said destination communication means further comprises destination register means for storing data, and wherein the destination buffer means allocation request by said source communication means to said destination communication means is provided to said destination register means. 
     
     
       43. A communication system comprising:
   source node means for sourcing data;        source communication means in communication with said source node means comprising source buffer means for storing data;        destination communication means in communication with said source communication means and comprising destination buffer means for storing data,        wherein, in response to a destination buffer means allocation request by said source communication means to said destination communication means, said destination communication means  ( i )  allocates a location within said destination buffer means to receive the data to be sent from said source communication means, and  ( ii )  provides at least the location of said destination buffer means to said source communication means, and        wherein said source communication means provides the data to said destination buffer means for storage at the location; and        destination node means for sinking data in communication with said destination communication means.     
     
     
       44. A communication system according to  claim 43 , wherein said source communication means further comprises first switching means for routing data responsive to a first plurality of source node means, and wherein said destination communication means further comprises second switching means for routing data in communication with a second plurality of destination node means. 
     
     
       45. A communication system according to  claim 44 , further comprising an address line means for transferring data and a data line means for transferring data, wherein the destination buffer means allocation request by said source communication means to said destination communication means is provided on said address line means, wherein said destination communication means provides the location of said destination buffer means to said source communication means on said address line means, and wherein said source communication means provides the data to said destination buffer means on said data line means. 
     
     
       46. A communication system according to  claim 45 , wherein said destination communication means provides ( i )  a start of the location of said destination buffer means to said source communication means on said address line means and  ( ii )  an address of said source communication means on said data line means.   
     
     
       47. A communication system according to  claim 45 , wherein said source communication means further comprises source register means for storing data, wherein the destination buffer means allocation request by said source communication means to said destination communication means comprises ( i )  an address of said source register means,  ( ii )  an address of said second switching means, and  ( iii )  an address of said first switching means on said address line means.   
     
     
       48. A communication system according to  claim 47 , wherein, in response to a destination buffer means allocation request by said source communication means to said destination communication means, said destination communication means further provides the location of said destination buffer means and an address of said source communication means to a start of packet register means in said source register means. 
     
     
       49. A communication system according to  claim 45 , wherein said source communication means further comprises source register means for storing data, and wherein the destination buffer means allocation request by said source communication means to said destination communication means comprises a size of the data to be transferred and an address of said source buffer means storing the data on said data line means. 
     
     
       50. A communication system according to  claim 45 , wherein, in response to a destination buffer means allocation request by said source communication means to said destination communication means, said destination communication means further provides the location of said destination buffer means and an address of said source communication means to said source communication means on said address line means. 
     
     
       51. A communication system according to  claim 43 , wherein, in response to a destination buffer means allocation request by said source communication means to said destination communication means, said destination communication means further provides the location of said destination buffer means and an address of said source communication means to said source communication means. 
     
     
       52. A communication system according to  claim 43 , wherein said destination communication means further comprises destination register means for storing data, and wherein the destination buffer means allocation request by said source communication means to said destination communication means is provided to said destination register means.