Difference between revisions of "BRIDGE"

From LinuxMIPS
Jump to: navigation, search
m
(added patent; clarified IP27/IP30 differences)
 
(One intermediate revision by the same user not shown)
Line 1: Line 1:
The '''BRIDGE''' [[Wikipedia:Application-specific_integrated_circuit|ASIC]] is used as the [[Wikipedia:Peripheral_Component_Interconnect|PCI]] hostbridge in the SGI [[IP27]] family of machines.  It interfaces between the internal Crosstalk connect one the one side and the 64-bit, 33MHz PCI bus on the other side.  It supports 32-bit PCI cards by providing an address translation mechanism allowing 32-bit PCI cards to access the entire 64-bit address space of the system.  BRIDGE also allows to specify a few attributes in 64-bit DMA addresses rsp. the address translation tables allowing to maximize performance.
+
The '''BRIDGE''' [[Wikipedia:Application-specific_integrated_circuit|ASIC]] is used as the [[Wikipedia:Peripheral_Component_Interconnect|PCI]] hostbridge in the SGI [[IP27]] family of machines, and also on SGI [[IP30]].  It interfaces between the internal [[XIO]] connect one the one side and the 64-bit, 33MHz PCI bus on the other side.  It supports 32-bit PCI cards by providing an address translation mechanism allowing 32-bit PCI cards to access the entire 64-bit address space of the system.  BRIDGE also allows to specify a few attributes in 64-bit DMA addresses or the address translation tables allowing to maximize performance. (There is also a direct mapping mechanism to support 2GB of mappable space on 32-bit cards, and it has limited support for attributes in a per-BRIDGE configuration.)
  
 
== Linux support ==
 
== Linux support ==
Linux support BRIDGE but is currently limited to 64-bit cards only.
+
Linux supports BRIDGE but is currently limited to 64-bit cards. This limitation applies only on [[IP27]]; the IP30 is a smaller machine and therefore can efficiently use the 2GB direct mapping mechanism.
  
 
== Related patents ==
 
== Related patents ==
* [[uspto:5,915,104|US patent 5,915,104]]
+
* [[uspto:5,915,104|US patent 5,915,104]], also [ftp://ftp.linux-mips.org/pub/linux/mips/people/skylark/pdf/bridge.pdf]

Latest revision as of 01:08, 7 October 2005

The BRIDGE ASIC is used as the PCI hostbridge in the SGI IP27 family of machines, and also on SGI IP30. It interfaces between the internal XIO connect one the one side and the 64-bit, 33MHz PCI bus on the other side. It supports 32-bit PCI cards by providing an address translation mechanism allowing 32-bit PCI cards to access the entire 64-bit address space of the system. BRIDGE also allows to specify a few attributes in 64-bit DMA addresses or the address translation tables allowing to maximize performance. (There is also a direct mapping mechanism to support 2GB of mappable space on 32-bit cards, and it has limited support for attributes in a per-BRIDGE configuration.)

Linux support

Linux supports BRIDGE but is currently limited to 64-bit cards. This limitation applies only on IP27; the IP30 is a smaller machine and therefore can efficiently use the 2GB direct mapping mechanism.

Related patents