throttle usb downloadHEADmaster

to work around what seems to be a musb fifo overrun
on some panda versions

Signed-off-by: John Rigby <john.rigby@linaro.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/usbboot.c b/usbboot.c
index bafcccf..da75498 100644
--- a/usbboot.c
+++ b/usbboot.c
@@ -36,6 +36,15 @@
 
 #include "usb.h"
 
+void throttled_usb_write(void *usb, void *data, int sz)
+{
+	while (sz > 0) {
+		usb_write(usb, data, 64);
+		data += 64;
+		sz -= 64;
+	}
+}
+
 int usb_boot(usb_handle * usb,
 	     void *data1, unsigned sz1, void *data2, unsigned sz2)
 {
@@ -99,7 +108,7 @@ int usb_boot(usb_handle * usb,
 		}
 		sleep(1);
 		fprintf(stderr, "transferring %d bytes of data\n", sz2);
-		usb_write(usb, data2, sz2);
+		throttled_usb_write(usb, data2, sz2);
 		fprintf(stderr, "write finished, waiting for \"OKAY\"\n");
 		usb_read(usb, response, sizeof(response));
 		if (strncmp("OKAY", response, 4) == 0) {