fel: implement simple progress bar for larger transfers

Add "--progress" option and a progress bar display for FEL
transfers. This picks up on a suggestion from Alexander Kaplan
and the discussion at
https://groups.google.com/forum/#!topic/linux-sunxi/lz0oQBwjex0

Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
Reviewed-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>

fel.c

@@ -81,7 +81,12 @@ static const int AW_USB_MAX_BULK_SEND = 4 * 1024 * 1024; // 4 MiB per bulk reque
 void usb_bulk_send(libusb_device_handle *usb, int ep, const void *data,
 		   size_t length, bool progress)
 {
-	size_t max_chunk = AW_USB_MAX_BULK_SEND; /* maximum chunk size */
+	/*
+	 * With no progress notifications, we'll use the maximum chunk size.
+	 * Otherwise, it's useful to lower the size (have more chunks) to get
+	 * more frequent status updates. 128 KiB per request seem suitable.
+	 */
+	size_t max_chunk = progress ? 128 * 1024 : AW_USB_MAX_BULK_SEND;
 
 	size_t chunk;
 	int rc, sent;
@@ -1215,6 +1220,7 @@ static int aw_fel_get_endpoint(libusb_device_handle *usb)
 
 int main(int argc, char **argv)
 {
+	bool pflag_active = false; /* -p switch, causing "write" to output progress */
 	int rc;
 	libusb_device_handle *handle = NULL;
 	int iface_detached = -1;
@@ -1224,6 +1230,7 @@ int main(int argc, char **argv)
 	if (argc <= 1) {
 		printf("Usage: %s [options] command arguments... [command...]\n"
 			"	-v, --verbose			Verbose logging\n"
+			"	-p, --progress			\"write\" transfers show a progress bar\n"
 			"\n"
 			"	spl file			Load and execute U-Boot SPL\n"
 			"		If file additionally contains a main U-Boot binary\n"
@@ -1283,7 +1290,11 @@ int main(int argc, char **argv)
 
 	while (argc > 1 ) {
 		int skip = 1;
-		if (strncmp(argv[1], "hex", 3) == 0 && argc > 3) {
+
+		if (strcmp(argv[1], "--progress") == 0 ||
+		    strcmp(argv[1], "-p") == 0) {
+			pflag_active = true;
+		} else if (strncmp(argv[1], "hex", 3) == 0 && argc > 3) {
 			aw_fel_hexdump(handle, strtoul(argv[2], NULL, 0), strtoul(argv[3], NULL, 0));
 			skip = 3;
 		} else if (strncmp(argv[1], "dump", 4) == 0 && argc > 3) {
@@ -1300,6 +1311,7 @@ int main(int argc, char **argv)
 			size_t size;
 			void *buf = load_file(argv[3], &size);
 			uint32_t offset = strtoul(argv[2], NULL, 0);
+			progress_start(pflag_active ? progress_bar : NULL, size);
 			double elapsed = aw_write_buffer(handle, buf, offset, size, true);
 			if (elapsed > 0)
 				pr_info("%.1f kB written in %.1f sec (speed: %.1f kB/s)\n",

progress.c

@@ -20,8 +20,6 @@
 #include <sys/time.h>
 #include <unistd.h>
 
-#include "common.h"
-
 /* Less reliable than clock_gettime, but does not require linking with -lrt */
 inline double gettime(void)
 {
@@ -30,11 +28,48 @@ inline double gettime(void)
 	return tv.tv_sec + (double)tv.tv_usec / 1000000.;
 }
 
+/* Private progress state variable */
+
+typedef struct {
+	progress_cb_t callback;
+	size_t total;
+	size_t done;
+} progress_private_t;
+
+static progress_private_t progress = {
+	.callback = NULL,
+};
+
+/* 'External' API */
+
+void progress_start(progress_cb_t callback, size_t expected_total)
+{
+	progress.callback = callback;
+	progress.total = expected_total;
+	progress.done = 0;
+}
+
 /* Update progress status, passing information to the callback function. */
-void progress_update(size_t UNUSED(bytes_done))
+void progress_update(size_t bytes_done)
 {
-	/*
-	 * This is a non-functional placeholder!
-	 * It will be replaced in a later patch.
-	 */
+	progress.done += bytes_done;
+	if (progress.callback)
+		progress.callback(progress.total, progress.done);
+}
+
+/* Callback function implementing a simple progress bar written to stdout */
+void progress_bar(size_t total, size_t done)
+{
+	static const int WIDTH = 60; /* # of characters to use for progress bar */
+
+	float ratio = total > 0 ? (float)done / total : 0;
+	int i, pos = WIDTH * ratio;
+
+	printf("\r%3.0f%% [", ratio * 100); /* current percentage */
+	for (i = 0; i < pos; i++) putchar('=');
+	for (i = pos; i < WIDTH; i++) putchar(' ');
+	printf("] ");
+
+	if (done >= total) putchar('\n'); /* output newline when complete */
+	fflush(stdout);
 }

progress.h

@@ -28,6 +28,10 @@ typedef void (*progress_cb_t)(size_t total, size_t done);
 
 double gettime(void);
 
+void progress_start(progress_cb_t callback, size_t expected_total);
 void progress_update(size_t bytes_done);
 
+/* progress callback implementations for various display styles */
+void progress_bar(size_t total, size_t done);
+
 #endif /* _SUNXI_TOOLS_PROGRESS_H */