Files
StarPilot/tinygrad_repo/extra/mlx_driver/loopback.py
T
firestar5683 22a8575199 Vendor dependencies and resources for standalone builds
Keep official openpilot ancestry and dependency licenses. Store resources directly in Git, remove LFS setup requirements, and leave the downloadable big model outside the source tree.
2026-10-03 21:01:18 +00:00

101 lines
4.0 KiB
Python

#!/usr/bin/env python3
# GMMU=0 MLX_PCI=0000:41:00.0 PYTHONPATH=. python3 extra/mlx_driver/loopback.py
import struct
from tinygrad.helpers import getenv, round_up
from tinygrad.device import Device, BufferSpec, Buffer
from tinygrad.dtype import dtypes
from tinygrad.runtime.support.system import PCIDevice
from tinygrad.runtime.support.memory import AddrSpace
from tinygrad.runtime.ops_amd import AMDComputeQueue
from tinygrad.helpers import to_be32, to_be64
from extra.mlx_driver.mlxdev import MLXDev, MLXQP
BUF_SIZE = 0x1000
MLX_PCI = getenv("MLX_PCI", "0000:41:00.0")
MLX_IP = getenv("MLX_IP", "10.0.0.1")
def map_phys_to_gpu(gpu, paddr, size):
size = round_up(size, 0x1000)
va = gpu.iface.dev_impl.mm.alloc_vaddr(size, align=0x1000)
gpu.iface.dev_impl.mm.map_range(va, size, [(paddr, size)], aspace=AddrSpace.SYS, snooped=True, uncached=True)
return va
print("[init] AMD GPU...")
gpu = Device["AMD"]
print(f"[init] MLX5 at {MLX_PCI}")
dev = MLXDev(PCIDevice("mlx5", MLX_PCI), ip=MLX_IP)
qp = MLXQP(dev)
print(f"[init] loopback connect QP 0x{qp.qp_info['qpn']:x}")
qp.connect(qp.qp_info['qpn'], dev.mac, int.from_bytes(dev.local_gid, 'big'))
# allocate src/dst via AMD GPU allocator
buf_src = Buffer(gpu.device, BUF_SIZE, dtypes.uint8, options=BufferSpec(nolru=True), preallocate=True)
buf_dst = Buffer(gpu.device, BUF_SIZE, dtypes.uint8, options=BufferSpec(nolru=True), preallocate=True)
bar_base = gpu.iface.pci_dev.bar_info(gpu.iface.vram_bar)[0]
src_paddr = buf_src.meta.mapping.paddrs[0][0] + bar_base
dst_paddr = buf_dst.meta.mapping.paddrs[0][0] + bar_base
print(f"src paddr=0x{src_paddr:x} dst paddr=0x{dst_paddr:x}")
# fill src, zero dst
test_msg = b"Hello from loopback send/recv!"
buf_src.copy_from(Buffer("PYTHON", BUF_SIZE, dtypes.uint8, opaque=memoryview(bytearray(test_msg.ljust(BUF_SIZE, b'\x00')))))
buf_dst.copy_from(Buffer("PYTHON", BUF_SIZE, dtypes.uint8, opaque=memoryview(bytearray(BUF_SIZE))))
gpu.synchronize()
# post recv WQE on RQ from CPU (scatter entry: byte_count, lkey, addr)
rq_mask = (1 << 4) - 1 # log_rq_size=4
rq_wqe = qp.qp_buf.view((qp.rq_head & rq_mask) * 16, 16)
rq_wqe[:] = struct.pack('>IIQ', len(test_msg), dev.mkey, dst_paddr)
qp.rq_head += 1
# ring recv doorbell from CPU (DBR offset 0 = recv counter)
dev.dbr[qp.qp_dbr // 4] = to_be32(qp.rq_head)
# build send WQE in SQ from CPU (opcode 0x0a = SEND, ds_count=2)
sq_head = qp.sq_head
sq_mask = (1 << qp.log_sq_size) - 1
wqe = qp.qp_buf.view(qp.sq_offset + (sq_head & sq_mask) * 64, 64)
wqe[:] = bytes(64)
wqe[0:8] = struct.pack('>II', (sq_head << 8) | 0x0a, (qp.qp_info['qpn'] << 8) | 2)
wqe[11] = 0x08 # CE: signal completion
wqe[16:32] = struct.pack('>IIQ', len(test_msg), dev.mkey, src_paddr)
qp.sq_head += 1
doorbell_val = to_be64(int.from_bytes(bytes(wqe[0:8]), 'big'))
# map MLX5 UAR and DBR into GPU VA
uar_paddr = dev.pci_dev.bar_info(0)[0] + dev.uar * 0x1000
uar_gpu_va = map_phys_to_gpu(gpu, uar_paddr, 0x1000)
dbr_gpu_va = map_phys_to_gpu(gpu, dev.dbr_paddrs[0], 0x1000)
print(f"UAR gpu_va=0x{uar_gpu_va:x} DBR gpu_va=0x{dbr_gpu_va:x}")
# GPU rings send doorbell via compute queue release_mem
q = AMDComputeQueue(gpu)
q.wait(gpu.timeline_signal, gpu.timeline_value - 1)
# write DBR (32-bit sq_head) - send doorbell at qp_dbr + 4
q.release_mem(dbr_gpu_va + qp.qp_dbr + 4, to_be32(qp.sq_head), q.pm4.data_sel__mec_release_mem__send_32_bit_low,
q.pm4.int_sel__mec_release_mem__none)
# write UAR doorbell (64-bit)
q.release_mem(uar_gpu_va + 0x800, doorbell_val, q.pm4.data_sel__mec_release_mem__send_64_bit_data,
q.pm4.int_sel__mec_release_mem__none)
q.signal(gpu.timeline_signal, gpu.next_timeline())
q.submit(gpu)
print("GPU kicked doorbell, waiting...")
gpu.synchronize()
# poll CQ from CPU (send + recv completions)
qp.poll_cq()
qp.poll_cq()
# read back
result = bytearray(BUF_SIZE)
result[:] = buf_dst.as_memoryview()
gpu.synchronize()
got = bytes(result[:len(test_msg)])
print(f"result: {got}")
assert got == test_msg, f"MISMATCH: {got} != {test_msg}"
print("RDMA loopback send/recv test passed (GPU-kicked)")