CUDA backend: backbone (#2075)

mlx/backend/cuda/utils.cpp

@@ -0,0 +1,26 @@
+// Copyright © 2025 Apple Inc.
+
+#include "mlx/backend/cuda/utils.h"
+#include "mlx/backend/cuda/device.h"
+
+#include <fmt/format.h>
+
+namespace mlx::core {
+
+CudaStream::CudaStream(cu::Device& device) {
+  device.make_current();
+  CHECK_CUDA_ERROR(cudaStreamCreateWithFlags(&stream_, cudaStreamNonBlocking));
+}
+
+CudaStream::~CudaStream() {
+  CHECK_CUDA_ERROR(cudaStreamDestroy(stream_));
+}
+
+void check_cuda_error(const char* name, cudaError_t err) {
+  if (err != cudaSuccess) {
+    throw std::runtime_error(
+        fmt::format("{} failed: {}", name, cudaGetErrorString(err)));
+  }
+}
+
+} // namespace mlx::core