Portal Interface Structure

Connectal connects software and hardware via portals, where each portal is an interface that allows one side to invoke methods on the other side.

We generally call a portal from software to hardware to be a “request” and from hardware to software to be an “indication” interface:

Sequence Diagram to be drawn
{
  SW; HW
  SW -> HW [label = "request"];
  SW <- HW [label = "indication"];
}

A portal is conceptually a FIFO, where the arguments to a method are packaged as a message. CONNECTAL generates a “proxy” that marshalls the arguments to the method into a message and a “wrapper” that unpacks the arguments and invokes the method.

Currently, connectal Includes a library that implements portals from software to hardware via memory mapped hardware FIFOs.

Portal Device Drivers

Connectal uses a platform-specific driver to enable user-space applications to memory-map each portal used by the application and to enable the application to wait for interrupts from the hardware.

indexterm:pcieportal indexterm:zynqportal

• pcieportal.ko

• zynqportal.ko

Connectal also uses a generic driver to enable the applications to allocate DRAM that will be shared with the hardware and to send the memory mapping of that memory to the hardware.

• portalmem.ko

Portal Memory Map

Connectal is designed to support multiple tiles, each of which can hold an independent design. Currently, the number of tiles is one.

Connectal currently supports up to 16 portals connected between software and hardware, for a total of 64KB of address space.

Base address	Function
0x0000	Portal 0
0x1000	Portal 1
0x2000	Portal 2
0x3000	Portal 3
0x4000	Portal 4
0x5000	Portal 5
0x6000	Portal 6
0x7000	Portal 7
0x8000	Portal 8
0x9000	Portal 9
0xa000	Portal 10
0xb000	Portal 11
0xc000	Portal 12
0xd000	Portal 13
0xe000	Portal 14
0xf000	Portal 15

Each portal uses 16KB of address space, consisting of a control register region and then per-method FIFOs, each of which takes 32 bytes of address space.

Base address	Function
0x000	Portal control regs
0x020	Method 0 FIFO
0x040	Method 1 FIFO
…	…

For request portals, the FIFOs are from software to hardware, and for indication portals the FIFOs are from hardware to software.

Portal FIFOs

Base address	Function
0x00	FIFO data (write request data, read indication data)
0x04	Request FIFO not full / Indication FIFO not empty

Portal Control Registers

Base address	Function	Description
0x00	Interrupt status register	1 if this portal has any messages ready, 0 otherwise
0x04	Interrupt enable register	Write 1 to enable interrupts, 0 to disable
0x08	Number of tiles
0x0C	Ready Channel number + 1	Reads as zero if no indication channel ready
0x10	Interface Id
0x14	Number of portals
0x18	Cycle count LSW	Snapshots MSW when read
0x1C	Cycle count MSW	MSW of cycle count when LSW was read