Add OpenCL example
Change-Id: Ie19675cef45864c1277eaa10587763fcb9248d46
diff --git a/Makefile b/Makefile
index 05d1d4e..870833a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-SUBDIRS := opengl
+SUBDIRS := opengl opencl
all: $(SUBDIRS)
$(SUBDIRS):
diff --git a/opencl/Makefile b/opencl/Makefile
new file mode 100644
index 0000000..b299bdd
--- /dev/null
+++ b/opencl/Makefile
@@ -0,0 +1,15 @@
+CROSS_COMPILE ?=
+CC = $(CROSS_COMPILE)gcc
+
+all: clexample
+
+%.o : %.c
+ $(CC) -c $(CFLAGS) $(CPPFLAGS) $< -o $@
+
+clexample: clexample.o
+ $(CC) -L /usr/lib/vivante -o $@ clexample.o -lOpenCL
+
+clean:
+ rm -f clexample *.o
+
+.PHONY: all clean
diff --git a/opencl/clexample.c b/opencl/clexample.c
new file mode 100644
index 0000000..e0ade1a
--- /dev/null
+++ b/opencl/clexample.c
@@ -0,0 +1,206 @@
+/*
+ * Copyright © 2020 Google LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#define CL_TARGET_OPENCL_VERSION 120
+#include <CL/cl.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+/* Max no of CL implementations, 5 should be enough to find CPU & GPU */
+#define MAX_PLATFORMS 5
+
+/* CL Program */
+const char *kKernels =
+ "__kernel void square(__global int *ARR) {"
+ " ARR[get_global_id(0)] = ARR[get_global_id(0)] * "
+ " ARR[get_global_id(0)];}"
+ "__kernel void add_arrays(__global int *ARR1, __global int *ARR2) {"
+ " ARR1[get_global_id(0)] = ARR1[get_global_id(0)] + "
+ " ARR2[get_global_id(0)];}"
+ "__kernel void add_const(__global int *ARR, const int c) {"
+ " ARR[get_global_id(0)] = ARR[get_global_id(0)] + c;}";
+
+/* Constant used in the calculations */
+const cl_int kAdd = 2;
+const size_t kArraySize = 1024;
+
+/*
+ * Function to carry out the CL elementwise calculations
+ * (out_array = in_array*in_array + in_array + 2)
+ */
+void Compute(cl_context ctx, cl_command_queue queue,
+ int *in_array, int *out_array, size_t size) {
+ cl_program program;
+ cl_int err;
+ cl_mem device_mem_1, device_mem_2;
+ cl_kernel kernel_square, kernel_add_const, kernel_add_arrays;
+
+ program = clCreateProgramWithSource(ctx, 1, (const char **) &kKernels,
+ NULL, &err);
+ err = clBuildProgram(program, 0, NULL, NULL, NULL, NULL);
+ kernel_square = clCreateKernel(program, "square", &err);
+ kernel_add_const = clCreateKernel(program, "add_const", &err);
+ kernel_add_arrays = clCreateKernel(program, "add_arrays", &err);
+
+ /* Initialize the data buffers */
+ device_mem_1 = clCreateBuffer(ctx, CL_MEM_READ_WRITE, size*sizeof(*in_array),
+ NULL, &err);
+ device_mem_2 = clCreateBuffer(ctx, CL_MEM_READ_WRITE, size*sizeof(*in_array),
+ NULL, &err);
+
+ /* Write and queue the input buffers */
+ err = clEnqueueWriteBuffer(queue, device_mem_1, CL_TRUE, 0, size*sizeof(*in_array),
+ in_array, 0, NULL, NULL);
+ err = clEnqueueWriteBuffer(queue, device_mem_2, CL_TRUE, 0, size*sizeof(*in_array),
+ in_array, 0, NULL, NULL);
+
+ /* Calculate the square the elements of the array */
+ clSetKernelArg(kernel_square, 0, sizeof(cl_mem), &device_mem_1);
+ clEnqueueNDRangeKernel(queue, kernel_square, 1, NULL, &size, &size, 0, NULL, NULL);
+
+ /* Add the current result to the original array */
+ clSetKernelArg(kernel_add_arrays, 0, sizeof(cl_mem), &device_mem_1);
+ clSetKernelArg(kernel_add_arrays, 1, sizeof(cl_mem), &device_mem_2);
+ clEnqueueNDRangeKernel(queue, kernel_add_arrays, 1, NULL, &size, &size, 0, NULL, NULL);
+
+ /* Add a constant to each element */
+ clSetKernelArg(kernel_add_const, 0, sizeof(cl_mem), &device_mem_1);
+ clSetKernelArg(kernel_add_const, 1, sizeof(int), &kAdd);
+ clEnqueueNDRangeKernel(queue, kernel_add_const, 1, NULL, &size, &size, 0, NULL, NULL);
+
+
+ /* Queue the output buffer, and kick off the calcuations */
+ err = clEnqueueReadBuffer(queue, device_mem_1, CL_TRUE, 0, size*sizeof(*out_array),
+ out_array, 0, NULL, NULL);
+ err = clFinish(queue);
+ clReleaseMemObject(device_mem_1);
+ clReleaseMemObject(device_mem_2);
+}
+
+/* Helper function to compare results */
+int CompareArrays(int *arr1, int *arr2, int no_elements) {
+ int success = 1;
+
+ for (int i=0; i<no_elements; i++) {
+ if (arr1[i] != arr2[i]) {
+ success = 0;
+ break;
+ }
+ }
+ return success;
+}
+
+int main( void ) {
+ cl_int err;
+ cl_platform_id platform;
+ cl_platform_id platforms[MAX_PLATFORMS];
+ cl_device_id device;
+ cl_context_properties props[3] = {CL_CONTEXT_PLATFORM, 0, 0};
+ cl_context ctx_gpu, ctx_cpu;
+ cl_command_queue queue_cpu;
+ cl_command_queue queue_gpu;
+ cl_event event = NULL;
+ int i, num_platforms;
+
+ int *input_arr, *result_cpu_arr, *gpu_result_arr, *expected_result_arr;
+
+ input_arr = (int*) malloc(kArraySize * sizeof(*input_arr));
+ gpu_result_arr = (int*) malloc(kArraySize * sizeof(*gpu_result_arr));
+ result_cpu_arr = (int*) malloc(kArraySize * sizeof(*result_cpu_arr));
+ expected_result_arr = (int*) malloc(kArraySize *
+ sizeof(*expected_result_arr));
+
+ /* Initialize input and expected arrays*/
+ for (i=0; i<kArraySize; i++) {
+ input_arr[i] = i;
+ expected_result_arr[i] = i*i+i+kAdd;
+ }
+
+ /* Get the platforms. */
+ err = clGetPlatformIDs(5, platforms, &num_platforms);
+
+ /* Setup one CPU and one GPU device */
+ device = NULL;
+ ctx_cpu = ctx_gpu = NULL;
+ for (i=0; i<num_platforms; i++) {
+ props[1] = (cl_context_properties) platforms[i];
+ if (ctx_cpu == NULL) {
+ err = clGetDeviceIDs(platforms[i], CL_DEVICE_TYPE_CPU,
+ 1, &device, NULL);
+ if (device != NULL) {
+ ctx_cpu = clCreateContext(props, 1, &device, NULL, NULL, &err);
+ queue_cpu = clCreateCommandQueue(ctx_cpu, device, 0, &err);
+ device = NULL;
+ continue;
+ }
+ }
+ if (ctx_gpu == NULL) {
+ err = clGetDeviceIDs(platforms[i], CL_DEVICE_TYPE_GPU,
+ 1, &device, NULL);
+ if (device != NULL) {
+ ctx_gpu = clCreateContext(props, 1, &device, NULL, NULL, &err);
+ queue_gpu = clCreateCommandQueue(ctx_gpu, device, 0, &err);
+ device = NULL;
+ continue;
+ }
+ }
+ }
+
+ /* Run the GPU computation */
+ if (ctx_gpu) {
+ Compute(ctx_gpu, queue_gpu, input_arr, gpu_result_arr, kArraySize);
+ clReleaseCommandQueue(queue_gpu);
+ clReleaseContext(ctx_gpu);
+
+ if (CompareArrays(expected_result_arr, gpu_result_arr, kArraySize))
+ printf("GPU: Result as expected\n");
+ else
+ printf("GPU: FAIL Result NOT as expected\n");
+ } else {
+ printf("GPU: FAIL No OpenCL implementation found\n");
+ }
+
+ /* Run the CPU computation */
+ if (ctx_cpu) {
+ Compute(ctx_cpu, queue_cpu, input_arr, result_cpu_arr, kArraySize);
+ clReleaseCommandQueue( queue_cpu );
+ clReleaseContext( ctx_cpu );
+
+ if (CompareArrays(expected_result_arr, result_cpu_arr, kArraySize))
+ printf("CPU: Result as expected\n");
+ else
+ printf("CPU: FAIL Result NOT as expected\n");
+ } else {
+ printf("CPU: FAIL No OpenCL implementation found\n");
+ }
+
+
+ /* Free the allocated memory */
+ free(input_arr);
+ free(result_cpu_arr);
+ free(gpu_result_arr);
+ free(expected_result_arr);
+
+ return 0;
+}
