tools: usb: aio example applications

This patch adds two example applications showing usage of Asynchronous I/O API
of FunctionFS. First one (aio_simple) is simple example of bidirectional data
transfer. Second one (aio_multibuff) shows multi-buffer data transfer, which
may to be used in high performance applications.

Both examples contains userspace applications for device and for host.
It needs libaio library on the device, and libusb library on host.

Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

tools/usb/ffs-aio-example/simple/host_app/Makefile

@@ -0,0 +1,13 @@
+CC = gcc
+LIBUSB_CFLAGS = $(shell pkg-config --cflags libusb-1.0)
+LIBUSB_LIBS = $(shell pkg-config --libs libusb-1.0)
+WARNINGS = -Wall -Wextra
+CFLAGS = $(LIBUSB_CFLAGS) $(WARNINGS)
+LDFLAGS = $(LIBUSB_LIBS)
+
+all: test
+%: %.c
+	$(CC) $(CFLAGS) -o $@ $^ $(LDFLAGS)
+
+clean:
+	$(RM) test

tools/usb/ffs-aio-example/simple/host_app/test.c

@@ -0,0 +1,148 @@
+#include <libusb.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#define VENDOR	0x1d6b
+#define PRODUCT	0x0105
+
+/* endpoints indexes */
+
+#define EP_BULK_IN	(1 | LIBUSB_ENDPOINT_IN)
+#define EP_BULK_OUT	(2 | LIBUSB_ENDPOINT_OUT)
+
+#define BUF_LEN		8192
+
+/*
+ * struct test_state - describes test program state
+ * @list: list of devices returned by libusb_get_device_list function
+ * @found: pointer to struct describing tested device
+ * @ctx: context, set to NULL
+ * @handle: handle of tested device
+ * @attached: indicates that device was attached to kernel, and has to be
+ *            reattached at the end of test program
+ */
+
+struct test_state {
+	libusb_device *found;
+	libusb_context *ctx;
+	libusb_device_handle *handle;
+	int attached;
+};
+
+/*
+ * test_init - initialize test program
+ */
+
+int test_init(struct test_state *state)
+{
+	int i, ret;
+	ssize_t cnt;
+	libusb_device **list;
+
+	state->found = NULL;
+	state->ctx = NULL;
+	state->handle = NULL;
+	state->attached = 0;
+
+	ret = libusb_init(&state->ctx);
+	if (ret) {
+		printf("cannot init libusb: %s\n", libusb_error_name(ret));
+		return 1;
+	}
+
+	cnt = libusb_get_device_list(state->ctx, &list);
+	if (cnt <= 0) {
+		printf("no devices found\n");
+		goto error1;
+	}
+
+	for (i = 0; i < cnt; ++i) {
+		libusb_device *dev = list[i];
+		struct libusb_device_descriptor desc;
+		ret = libusb_get_device_descriptor(dev, &desc);
+		if (ret) {
+			printf("unable to get device descriptor: %s\n",
+			       libusb_error_name(ret));
+			goto error2;
+		}
+		if (desc.idVendor == VENDOR && desc.idProduct == PRODUCT) {
+			state->found = dev;
+			break;
+		}
+	}
+
+	if (!state->found) {
+		printf("no devices found\n");
+		goto error2;
+	}
+
+	ret = libusb_open(state->found, &state->handle);
+	if (ret) {
+		printf("cannot open device: %s\n", libusb_error_name(ret));
+		goto error2;
+	}
+
+	if (libusb_claim_interface(state->handle, 0)) {
+		ret = libusb_detach_kernel_driver(state->handle, 0);
+		if (ret) {
+			printf("unable to detach kernel driver: %s\n",
+			       libusb_error_name(ret));
+			goto error3;
+		}
+		state->attached = 1;
+		ret = libusb_claim_interface(state->handle, 0);
+		if (ret) {
+			printf("cannot claim interface: %s\n",
+			       libusb_error_name(ret));
+			goto error4;
+		}
+	}
+
+	return 0;
+
+error4:
+	if (state->attached == 1)
+		libusb_attach_kernel_driver(state->handle, 0);
+
+error3:
+	libusb_close(state->handle);
+
+error2:
+	libusb_free_device_list(list, 1);
+
+error1:
+	libusb_exit(state->ctx);
+	return 1;
+}
+
+/*
+ * test_exit - cleanup test program
+ */
+
+void test_exit(struct test_state *state)
+{
+	libusb_release_interface(state->handle, 0);
+	if (state->attached == 1)
+		libusb_attach_kernel_driver(state->handle, 0);
+	libusb_close(state->handle);
+	libusb_exit(state->ctx);
+}
+
+int main(void)
+{
+	struct test_state state;
+
+	if (test_init(&state))
+		return 1;
+
+	while (1) {
+		static unsigned char buffer[BUF_LEN];
+		int bytes;
+		libusb_bulk_transfer(state.handle, EP_BULK_IN, buffer, BUF_LEN,
+				     &bytes, 500);
+		libusb_bulk_transfer(state.handle, EP_BULK_OUT, buffer, BUF_LEN,
+				     &bytes, 500);
+	}
+	test_exit(&state);
+}