This patch does three things:
1) it replaces get_data_token with a simpler and more efficient
version that doesn't unconditionally toggle
2) it only toggles the transmitter-side sequence if the DATAx
packet is acknowledged (USB 1.1 sec 8.6 pg 168 and USB 2.0
sec 8.6 pg 232)
3) it always sends DATA1 in the status stage, in accordance with
USB 1.1 sec 8.5.2 pg 165 and USB 2.0 sec 8.5.3 pg 226.
In testing, this patch reduced the probability of the low-speed device
used (the Rii RF keyboard) registering. This seems to simply be the
effect of bugs eliminated in later patches having a greater effect,
and does not constitute a regression of code correctness.
---
softusb-input/main.c | 20 ++++++++------------
1 files changed, 8 insertions(+), 12 deletions(-)
diff --git a/softusb-input/main.c b/softusb-input/main.c
index 3b2e521..3d8ca17 100644
--- a/softusb-input/main.c
+++ b/softusb-input/main.c
@@ -151,13 +151,9 @@ struct setup_packet {
unsigned char wLength[2];
} __attribute__((packed));
-static inline unsigned char get_data_token(char *toggle)
+static inline unsigned char toggle(unsigned char old)
{
- *toggle = !(*toggle);
- if(*toggle)
- return USB_PID_DATA0;
- else
- return USB_PID_DATA1;
+ return old ^ USB_PID_DATA0 ^ USB_PID_DATA1;
}
static const char control_failed[] PROGMEM = "Control transfer failed:\n";
@@ -170,17 +166,15 @@ static char control_transfer(unsigned char addr, struct
setup_packet *p, char ou
{
unsigned char setup[11];
unsigned char usb_buffer[11];
- char toggle;
+ unsigned char expected_data = USB_PID_DATA1;
char rxlen;
char transferred;
char chunklen;
- toggle = 0;
-
/* generate SETUP token */
make_usb_token(USB_PID_SETUP, addr, setup);
/* generate setup packet */
- usb_buffer[0] = get_data_token(&toggle);
+ usb_buffer[0] = USB_PID_DATA0;
memcpy(&usb_buffer[1], p, 8);
usb_crc16(&usb_buffer[1], 8, &usb_buffer[9]);
#ifdef TRIGGER
@@ -215,10 +209,11 @@ wio8(SIE_SEL_TX, 2);
make_usb_token(USB_PID_OUT, addr, usb_buffer);
usb_tx(usb_buffer, 3);
/* send DATAx packet */
- usb_buffer[0] = get_data_token(&toggle);
+ usb_buffer[0] = expected_data;
memcpy(&usb_buffer[1], payload, chunklen);
usb_crc16(&usb_buffer[1], chunklen,
&usb_buffer[chunklen+1]);
usb_tx(usb_buffer, chunklen+3);
+
/* get ACK from device */
rxlen = usb_rx(usb_buffer, 11);
if((rxlen != 1) || (usb_buffer[0] != USB_PID_ACK)) {
@@ -231,6 +226,7 @@ wio8(SIE_SEL_TX, 2);
return -1;
}
+ expected_data = toggle(expected_data);
transferred += chunklen;
payload += chunklen;
if(chunklen < 8)
@@ -291,7 +287,7 @@ retry:
usb_tx(usb_buffer, 1);
} else {
/* send DATAx packet */
- usb_buffer[0] = get_data_token(&toggle);
+ usb_buffer[0] = USB_PID_DATA1;
usb_buffer[1] = usb_buffer[2] = 0x00; /* CRC is 0x0000 without
data */
usb_tx(usb_buffer, 3);
/* get ACK token from device */
--
1.7.1
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