halfkay.c: usbsendmd: fix fast transmit EPIPE

Fixed an issue where transmitting too quickly would cause a
LIBUSB_ERROR_PIPE after the third transmission. For the future the delay
might want to back off and the initial delay could be shortened.

1 files changed, 11 insertions, 7 deletions

diff --git a/halfkay.c b/halfkay.c
index 755a84e..cfb10ce 100644
--- a/halfkay.c
+++ b/halfkay.c
@@ -38,6 +38,10 @@ enum {
 			 | LIBUSB_RECIPIENT_INTERFACE),
 	HK_USB_REQ = LIBUSB_REQUEST_SET_CONFIGURATION,
 	HK_USB_VAL = 0x200,
+	TIMEOUT = 2000,
+	TIMEOUT_FIRST = 3000,
+	TRANS_DELAY = 10000,
+	TRANS_ATTEMPTS = 10,
 };
 
 libusb_device_handle *hk_usb_hnd;
@@ -74,17 +78,17 @@ static void usbclose(void)
 
 static void usbsendcmd(void *data, size_t size, bool firstxfer)
 {
-	unsigned int timeout = firstxfer ? 3000 : 2000;
-	int rc;
+	unsigned int timeout = firstxfer ? TIMEOUT_FIRST : TIMEOUT;
+	int rc, attempt = 0;
 
-	rc = libusb_control_transfer(hk_usb_hnd, HK_USB_REQTYP, HK_USB_REQ,
-				     HK_USB_VAL, 0, data, size, timeout);
+	do {
+		rc = libusb_control_transfer(hk_usb_hnd, HK_USB_REQTYP, HK_USB_REQ,
+					     HK_USB_VAL, 0, data, size, timeout);
+		usleep(TRANS_DELAY);
+	} while (rc == LIBUSB_ERROR_PIPE && ++attempt < TRANS_ATTEMPTS);
 
 	if (rc < 0)
 		libusb_err("transfer", rc);
-
-	/* TODO: Replace this with the correct way to handle a halt... ffs idiot */
-	usleep(10000); /* HalfKay says no if you write too fast */
 }
 
 static void fmtcmd(void *_dest, const struct flashparams *fp, size_t addr)