[v2,2/2] selftests/dma: add test application for DMA_MAP_BENCHMARK

diff --git a/MAINTAINERS b/MAINTAINERS
index 608fc8484c02..a1e38d5e14f6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5247,6 +5247,12 @@  F:	include/linux/dma-mapping.h
 F:	include/linux/dma-map-ops.h
 F:	kernel/dma/
 
+DMA MAPPING BENCHMARK
+M:	Barry Song <song.bao.hua@hisilicon.com>
+L:	iommu@lists.linux-foundation.org
+F:	kernel/dma/map_benchmark.c
+F:	tools/testing/selftests/dma/
+
 DMA-BUF HEAPS FRAMEWORK
 M:	Sumit Semwal <sumit.semwal@linaro.org>
 R:	Benjamin Gaignard <benjamin.gaignard@linaro.org>
diff --git a/tools/testing/selftests/dma/Makefile b/tools/testing/selftests/dma/Makefile
new file mode 100644
index 000000000000..aa8e8b5b3864
--- /dev/null
+++ b/tools/testing/selftests/dma/Makefile
@@ -0,0 +1,6 @@ 
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS += -I../../../../usr/include/
+
+TEST_GEN_PROGS := dma_map_benchmark
+
+include ../lib.mk
diff --git a/tools/testing/selftests/dma/config b/tools/testing/selftests/dma/config
new file mode 100644
index 000000000000..6102ee3c43cd
--- /dev/null
+++ b/tools/testing/selftests/dma/config
@@ -0,0 +1 @@ 
+CONFIG_DMA_MAP_BENCHMARK=y
diff --git a/tools/testing/selftests/dma/dma_map_benchmark.c b/tools/testing/selftests/dma/dma_map_benchmark.c
new file mode 100644
index 000000000000..4778df0c458f
--- /dev/null
+++ b/tools/testing/selftests/dma/dma_map_benchmark.c
@@ -0,0 +1,87 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020 Hisilicon Limited.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <linux/types.h>
+
+#define DMA_MAP_BENCHMARK	_IOWR('d', 1, struct map_benchmark)
+#define DMA_MAP_MAX_THREADS	1024
+#define DMA_MAP_MAX_SECONDS     300
+
+struct map_benchmark {
+	__u64 avg_map_100ns; /* average map latency in 100ns */
+	__u64 map_stddev; /* standard deviation of map latency */
+	__u64 avg_unmap_100ns; /* as above */
+	__u64 unmap_stddev;
+	__u32 threads; /* how many threads will do map/unmap in parallel */
+	__u32 seconds; /* how long the test will last */
+	int node; /* which numa node this benchmark will run on */
+	__u64 expansion[10];	/* For future use */
+};
+
+int main(int argc, char **argv)
+{
+	struct map_benchmark map;
+	int fd, opt;
+	/* default single thread, run 20 seconds on NUMA_NO_NODE */
+	int threads = 1, seconds = 20, node = -1;
+	int cmd = DMA_MAP_BENCHMARK;
+	char *p;
+
+	while ((opt = getopt(argc, argv, "t:s:n:")) != -1) {
+		switch (opt) {
+		case 't':
+			threads = atoi(optarg);
+			break;
+		case 's':
+			seconds = atoi(optarg);
+			break;
+		case 'n':
+			node = atoi(optarg);
+			break;
+		default:
+			return -1;
+		}
+	}
+
+	if (threads <= 0 || threads > DMA_MAP_MAX_THREADS) {
+		fprintf(stderr, "invalid number of threads, must be in 1-%d\n",
+			DMA_MAP_MAX_THREADS);
+		exit(1);
+	}
+
+	if (seconds <= 0 || seconds > DMA_MAP_MAX_SECONDS) {
+		fprintf(stderr, "invalid number of seconds, must be in 1-%d\n",
+			DMA_MAP_MAX_SECONDS);
+		exit(1);
+	}
+
+	fd = open("/sys/kernel/debug/dma_map_benchmark", O_RDWR);
+	if (fd == -1) {
+		perror("open");
+		exit(1);
+	}
+
+	map.seconds = seconds;
+	map.threads = threads;
+	map.node = node;
+	if (ioctl(fd, cmd, &map)) {
+		perror("ioctl");
+		exit(1);
+	}
+
+	printf("dma mapping benchmark: threads:%d seconds:%d\n", threads, seconds);
+	printf("average map latency(us):%.1f standard deviation:%.1f\n",
+			map.avg_map_100ns/10.0, map.map_stddev/10.0);
+	printf("average unmap latency(us):%.1f standard deviation:%.1f\n",
+			map.avg_unmap_100ns/10.0, map.unmap_stddev/10.0);
+
+	return 0;
+}