Hi,
Lukasz Majewski <lu...@denx.de> writes:
>> Lukasz Majewski <lu...@denx.de> writes:
>> >> Lukasz Majewski <lu...@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.
>>
>> Here's what I used for testing:
>
> I do appreciate that you tested it - even better, that with different
> approach.
>
> However, some time ago Stephen Warren has rewritten tests for DFU, UMS
> to use some python infrastructure. Those tests (especially DFU, test
> corner cases - ZLP, +/-1B to packet size, etc).
that's exactly what I tested :-)
> If you want, you can add your board to them.
I'll see how to do that and maybe add to the TODO list
--
balbi
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