Hi Felipe,
Hi Lukasz,
Lukasz Majewski lukma@denx.de writes:
drivers/usb/gadget/f_dfu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/f_dfu.c b/drivers/usb/gadget/f_dfu.c index 8e7c981657..64cdfa7c98 100644 --- a/drivers/usb/gadget/f_dfu.c +++ b/drivers/usb/gadget/f_dfu.c @@ -159,7 +159,7 @@ static void dnload_request_complete(struct usb_ep *ep, struct usb_request *req) int ret;
ret = dfu_write(dfu_get_entity(f_dfu->altsetting), req->buf,
- req->length, f_dfu->blk_seq_num);
- req->actual, f_dfu->blk_seq_num);
DFU driver queues a request to USB controller. Per the gadget API req->length contains maximum amount of data to be transmitted. req->actual is written by USB controller with the actual amount of data that we transmitted.
In the case of IN (TX), upon completion req->length and req->actual should always be equal (unless errors show up, etc)
In the case of OUT (RX), upon completion req->actual MAY BE less than req->length and that's not an error. Say host sent us a short packet which causes early termination of transfer.
With that in mind, let's consider the situation where we're receiving data from host using DFU. Let's assume that we have a 4096 byte buffer for transfers and we're receiving a binary that's 7679 bytes in size.
Here's what we will do (pseudo-code):
int remaining = 7679; char buf[4096];
while (remaining) { req->length = 4096; req->buf = buf; usb_ep_queue(req);
/* wait for completion */
remaining -= req->actual;
dfu_write(buf, req->length); /* this is the error */ }
Can you see here that in the last packet we will write 4096 bytes when we should write only 3583?
In principle you are right. I need to check if this change will not introduce regressions.
Can you share your use case?
Intel Edison running v2017.03-rc1 + patches (see [1]), flashing u-boot.bin over DFU (see [2] for details). Without $subject, image has to be aligned to 4096 bytes as below:
$ dd if=u-boot.bin of=u-boot-4k.bin bs=4k seek=1 && truncate -s %4096 u-boot-4k.bin
With $subject, I don't need truncate. We still need the 4096 byte of zeroes in the beginning of the image for other reasons (which I really don't know why at this point).
[1] https://github.com/andy-shev/u-boot/tree/edison [2] https://communities.intel.com/message/435516#435516
Ok. I will check this. Thanks for pointing out :-)
Any updates here? I'd like to send Tangier Soc and Intel Edison Board support but I kinda depend on this patch making upstream. I can resend as part of the "add intel edison" series.
Let me know
I'm setting up /test/py/dfu now on BBB. I will let you know by EOD.
Best regards,
Lukasz Majewski
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