Support program-scope host pipes

[pcolberg]

Support program-scope host pipes as part of SYCL_INTEL_data_flow_pipes, which are statically allocated in the OpenCL program and communicated from the FPGA compiler to the FPGA runtime via the auto-discovery string.

[pcolberg]

The runtime currently implements cl_mem object-based host pipes, which are dynamically allocated at run-time.

FPGA runtime layer

• clCreatePipeIntelFPGA()
• clReadPipeIntelFPGA()
• clWritePipeIntelFPGA()
• host_op_t
• host_pipe_t *host_pipe_info stores the mapping of a pipe object to an MMD host channel. The kernel m_binded_kernel associated with a pipe is stored in clSetKernelArgIntelFPGA. The mapping of the pipe to a host channel is delayed till programming the device, at the end of acl_program_device(), which calls acl_bind_and_process_all_pipes_transactions() that iterates over all pipes in the associated program and invokes acl_bind_pipe_to_channel() on each pipe, which in turn calls acl_hal_mmd_hostchannel_create().
• pipe_objs stores the packet size in bytes and the maximum number of packets in the pipe. Its members are initialized in clCreatePipeIntelFPGA().
• acl_hostpipe_info_t is used in acl_device_def_autodiscovery_t to store the compile-time host pipe attributes passed via the auto-discovery string of a program. The information is set in acl_load_device_def_from_str() and includes the string name of the pipe, the direction of the pipe, the data width in bytes corresponding to the packet size, and the maximum depth that limits the maximum number of packets.

HAL layer

• acl_hal_mmd_hostchannel_create() wraps aocl_mmd_hostchannel_create(). The physical device ID is mapped to the PCIE device handle. The packet size multiplied by the number of packets yields the queue depth, which is the size in bytes of pinned host memory for the queue.
• acl_hal_mmd_hostchannel_destroy()
• acl_hal_mmd_hostchannel_pull()
• acl_hal_mmd_hostchannel_push()
• acl_hal_mmd_hostchannel_get_buffer()
• acl_hal_mmd_hostchannel_ack_buffer()

MMD layer

• aocl_mmd_hostchannel_create()
• aocl_mmd_hostchannel_destroy()
• aocl_mmd_hostchannel_get_buffer()
• aocl_mmd_hostchannel_ack_buffer()

[zibaiwan]

Closed by #284.