Hot plug process in a distributed interconnect bus

Abstract

A wireless communication system comprises a root component connected in a host device and directly coupled to an upstream bus unit, wherein the upstream bus unit is configured to maintain a first configuration space and a copy of a second configuration space, the first configuration space bridge includes at least hot-plug registers specifying at least capabilities and status of a slot of the upstream bus unit; and at least one endpoint component connected to at least one peripheral device and directly coupled to a downstream bus unit that communicates with the host bridge over a distributed link established over a distributed peripheral component interconnect express (PCIe) bus, wherein the downstream bus unit is configured to maintain the second configuration space; the second configuration space includes at least hot-plug registers specifying at least capabilities and status of a slot of the downstream bus unit.

What is claimed is: 
     
         1 . A method for performing a hot-plug removal process in a distributed peripheral component interconnect express (PCIe) bus, comprising:
 receiving a hot-plug interrupt asserted by a shadow configuration space when a distributed link established over the distributed PCIe is unavailable, wherein the shadow configuration space is a copy of a configuration space of at least one endpoint component wirelessly connected to a host device over the distributed PCIe;   reading a hot-plug status from the shadow configuration space;   writing to the shadow configuration space to turn off at least one peripheral device connected to the at least one endpoint component; and   de-allocating resources allocated to a driver of the at least one peripheral.   
     
     
         2 . The method of  claim 1 , wherein the shadow configuration space is maintained in an upstream bus unit connected to a root component of the host device, wherein the configuration space is maintained in a downstream bus unit coupled to the at least one endpoint component, the upstream bus unit and the downstream bus unit communicate over the distributed link. 
     
     
         3 . The method of  claim 1 , wherein the configuration space includes at least hot-plug registers (HPR) specifying at least capabilities and status of at least one the downstream bus unit and the at least one endpoint component. 
     
     
         4 . The method of  claim 3 , wherein the hot-plug registers include at least a slot control register, a slot status register, and a slot capabilities register. 
     
     
         5 . The method of  claim 3 , wherein writing to the shadow configuration space includes writing to the hot-plug registers using a configuration write packet. 
     
     
         6 . The method of  claim 2 , wherein a new version of the configuration space is copied to the upstream bus unit upon any change in the configuration space. 
     
     
         7 . A non-transitory computer readable medium having stored thereon instructions for causing one or more processing units to execute the method of  claim 1 . 
     
     
         8 . A method for performing a hot-plug insertion process in a distributed peripheral component interconnect express (PCIe) bus, comprising:
 receiving a hot-plug interrupt asserted by a shadow configuration space when a distributed link established over the distributed PCIe is available, the hot-plug interrupt informing on detection of a hot-plug insertion event;   reading a hot-plug status from a configuration space of at least one endpoint component wirelessly connected to a host device over the distributed PCIe, wherein the configuration space is a copy of the shadow configuration space updated to designate the hot-plug insertion event;   writing to the configuration space to turn on at least one peripheral device connected to the at least one endpoint component; and   asserting a message indicating that the host device and the at least one peripheral can communicate over the distributed PCIe bus.   
     
     
         9 . The method of  claim 8 , further comprising:
 enumerating the distributed PCIe bus to include the at least one endpoint component.   
     
     
         10 . The method of  claim 8 , wherein the shadow configuration space is maintained in an upstream bus unit connected to a root component of the host device, wherein the configuration space is maintained in a downstream bus unit coupled to the at least one endpoint component, the upstream bus unit and the downstream bus unit communicate over the distributed link. 
     
     
         11 . The method of  claim 8 , wherein the configuration space includes at least hot-plug registers (HPR) specifying at least capabilities and status of at least one of the downstream bus unit and the at least one endpoint component. 
     
     
         12 . The method of  claim 3 , wherein the hot-plug registers include at least a slot control register, a slot status register, and a slot capabilities register. 
     
     
         13 . The method of  claim 8 , wherein writing to the configuration space includes writing to the hot-plug registers using a configuration write packet. 
     
     
         14 . A non-transitory computer readable medium having stored thereon instructions for causing one or more processing units to execute the method of  claim 8 . 
     
     
         15 . A wireless communication system, comprising:
 a root component connected in a host device and directly coupled to an upstream bus unit, wherein the upstream bus unit is configured to maintain a first configuration space and a copy of a second configuration space, the first configuration space bridge includes at least hot-plug registers specifying at least capabilities and status of a slot of the upstream bus unit; and   at least one endpoint component connected to at least one peripheral device and directly coupled to a downstream bus unit that communicates with the host bridge over a distributed link established over a distributed peripheral component interconnect express (PCIe) bus, wherein the downstream bus unit is configured to maintain the second configuration space; the second configuration space includes at least hot-plug registers specifying at least capabilities and status of a slot of the downstream bus unit.   
     
     
         16 . The wireless communication system of  claim 15 , wherein when the distributed link status changes from available to unavailable a hot-plug removal event is triggered. 
     
     
         17 . The wireless communication system of  claim 16 , wherein the second configuration space is copied to the upstream bus unit when the link is available. 
     
     
         18 . The wireless communication system of  claim 17 , wherein the second configuration space in the downstream bus unit is updated with the hot-plug removal event. 
     
     
         19 . The wireless communication system of  claim 18 , wherein an operating system of the host device accesses the copy of the second configuration space in the upstream bus unit during a hot-plug removal process performed by the operating system. 
     
     
         20 . The wireless communication system of  claim 15 , wherein when the distributed link status changes from unavailable to available a hot-plug insertion event. 
     
     
         21 . The wireless communication system of  claim 20 , wherein the copy of the second configuration space is copied from the upstream bus unit to the downstream bus unit. 
     
     
         22 . The wireless communication system of  claim 21 , wherein the operating system accesses the second configuration space in the downstream bus unit during a hot-plug insertion process performed by the operating system.