added sample to porting driver guide

Change-Id: Ia2b54311cec617e5e2a162fd31415c8caad4a374

hipamd/docs/markdown/hip_porting_driver_api.md

@@ -171,3 +171,83 @@ hipFunction k;
 hipModuleGetFunction(&k, module, "myKernel");
 ```
 
+The below sample shows how to use `hipModuleGetFunction`.
+
+```
+#include<hip_runtime.h>
+#include<hip_runtime_api.h>
+#include<iostream>
+#include<fstream>
+#include<vector>
+
+#define LEN 64
+#define SIZE LEN<<2
+
+#ifdef __HIP_PLATFORM_HCC__
+#define fileName "vcpy_isa.co"
+#endif
+
+#ifdef __HIP_PLATFORM_NVCC__
+#define fileName "vcpy_isa.ptx"
+#endif
+
+#define kernel_name "hello_world"
+
+int main(){
+    float *A, *B;
+    hipDeviceptr_t Ad, Bd;
+    A = new float[LEN];
+    B = new float[LEN];
+
+    for(uint32_t i=0;i<LEN;i++){
+        A[i] = i*1.0f;
+        B[i] = 0.0f;
+        std::cout<<A[i] << " "<<B[i]<<std::endl;
+    }
+
+
+#ifdef __HIP_PLATFORM_NVCC__
+          hipInit(0);
+          hipDevice_t device;
+          hipCtx_t context;
+          hipDeviceGet(&device, 0);
+          hipCtxCreate(&context, 0, device);
+#endif
+
+    hipMalloc((void**)&Ad, SIZE);
+    hipMalloc((void**)&Bd, SIZE);
+
+    hipMemcpyHtoD(Ad, A, SIZE);
+    hipMemcpyHtoD(Bd, B, SIZE);
+    hipModule_t Module;
+    hipFunction_t Function;
+    hipModuleLoad(&Module, fileName);
+    hipModuleGetFunction(&Function, Module, kernel_name);
+
+    std::vector<void*>argBuffer(2);
+    memcpy(&argBuffer[0], &Ad, sizeof(void*));
+    memcpy(&argBuffer[1], &Bd, sizeof(void*));
+
+    size_t size = argBuffer.size()*sizeof(void*);
+
+    void *config[] = {
+      HIP_LAUNCH_PARAM_BUFFER_POINTER, &argBuffer[0],
+      HIP_LAUNCH_PARAM_BUFFER_SIZE, &size,
+      HIP_LAUNCH_PARAM_END
+    };
+
+    hipModuleLaunchKernel(Function, 1, 1, 1, LEN, 1, 1, 0, 0, NULL, (void**)&con                                     fig);
+
+    hipMemcpyDtoH(B, Bd, SIZE);
+    for(uint32_t i=0;i<LEN;i++){
+        std::cout<<A[i]<<" - "<<B[i]<<std::endl;
+    }
+
+#ifdef __HIP_PLATFORM_NVCC__
+          hipCtxDetach(context);
+#endif
+
+    return 0;
+}
+
+```