Re: [RFC wpan-next] atusb: add support for trac feature

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Alexander,

aahringo@redhat.com wrote on Mon, 5 Sep 2022 07:16:42 -0400:

> Hi,
> 
> On Sun, Sep 4, 2022 at 11:22 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> >
> > Hi Alexander,
> >
> > aahringo@redhat.com wrote on Sun,  4 Sep 2022 20:55:44 -0400:
> >  
> > > This patch adds support for reading the trac register if atusb firmware
> > > reports tx done. There is currently a feature to compare a sequence
> > > number, if the payload is 1 it tells the driver only the sequence number
> > > is available if it's two there is additional the trac status register as
> > > payload.
> > >
> > > Currently the atusb_in_good() function determines if it's a tx done or
> > > rx done if according the payload length. This patch is doing the same
> > > and assumes this behaviour.
> > >
> > > Signed-off-by: Alexander Aring <aahringo@redhat.com>
> > > ---
> > >
> > > Just an RFC, need another weekend to test it.
> > >
> > >  drivers/net/ieee802154/atusb.c | 33 ++++++++++++++++++++++++++++-----
> > >  1 file changed, 28 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/drivers/net/ieee802154/atusb.c b/drivers/net/ieee802154/atusb.c
> > > index 2c338783893d..95a4a3cdc8a4 100644
> > > --- a/drivers/net/ieee802154/atusb.c
> > > +++ b/drivers/net/ieee802154/atusb.c
> > > @@ -191,7 +191,7 @@ static void atusb_work_urbs(struct work_struct *work)
> > >
> > >  /* ----- Asynchronous USB -------------------------------------------------- */
> > >
> > > -static void atusb_tx_done(struct atusb *atusb, u8 seq)
> > > +static void atusb_tx_done(struct atusb *atusb, u8 seq, int reason)
> > >  {
> > >       struct usb_device *usb_dev = atusb->usb_dev;
> > >       u8 expect = atusb->tx_ack_seq;
> > > @@ -199,7 +199,10 @@ static void atusb_tx_done(struct atusb *atusb, u8 seq)
> > >       dev_dbg(&usb_dev->dev, "%s (0x%02x/0x%02x)\n", __func__, seq, expect);
> > >       if (seq == expect) {
> > >               /* TODO check for ifs handling in firmware */
> > > -             ieee802154_xmit_complete(atusb->hw, atusb->tx_skb, false);
> > > +             if (reason == IEEE802154_SUCCESS)
> > > +                     ieee802154_xmit_complete(atusb->hw, atusb->tx_skb, false);
> > > +             else
> > > +                     ieee802154_xmit_error(atusb->hw, atusb->tx_skb, reason);
> > >       } else {
> > >               /* TODO I experience this case when atusb has a tx complete
> > >                * irq before probing, we should fix the firmware it's an
> > > @@ -215,7 +218,8 @@ static void atusb_in_good(struct urb *urb)
> > >       struct usb_device *usb_dev = urb->dev;
> > >       struct sk_buff *skb = urb->context;
> > >       struct atusb *atusb = SKB_ATUSB(skb);
> > > -     u8 len, lqi;
> > > +     int result = IEEE802154_SUCCESS;
> > > +     u8 len, lqi, trac;
> > >
> > >       if (!urb->actual_length) {
> > >               dev_dbg(&usb_dev->dev, "atusb_in: zero-sized URB ?\n");
> > > @@ -224,8 +228,27 @@ static void atusb_in_good(struct urb *urb)
> > >
> > >       len = *skb->data;
> > >
> > > -     if (urb->actual_length == 1) {
> > > -             atusb_tx_done(atusb, len);
> > > +     switch (urb->actual_length) {
> > > +     case 2:
> > > +             trac = TRAC_MASK(*(skb->data + 1));  
> >
> > I've been fighting all night thinking the issues were on the atusb side
> > (it was horribly difficult to get the atusb toolchain up and running,
> > I'll send a patch to update the instructions), in particular because of  
> 
> Really? for me it was just apt install avr-gcc libc-avr (or what the
> debian packages name is).

I feel so bad. All the instructions I could find (from 2011) advised to
download an old gcc, an old binutils and old avr-lib, to compile
everything by hand... 2 out of 3 archives returned a 404 error, the
builds were chaotic I had to disable -Werror and fix many issues
manually, then I had to fight with binutils assembler failing, I tried
4 different versions before I got it right... I did write a commit to
update the instructions but if you say that just downloading the stock
pre-compiled binaries worked I am a bit disappointed because the
instructions specifically told not to do so.

> Then the dfu-util and be sure you invoke
> dfu-util (as root because you might need some udev rules otherwise)
> when the atusb is booting up.

Yes, dfu worked right away, very nice tool.

> > the data[2] definition which needed to be declared static outside of
> > the functions (see the other mail) and, I guess, because of this
> > beginner error: I was using skb->data[1] but of course it can't work.
> >  
> 
> mhh, I am sorry. I am not sure if I understand what you mean? Does the
> firmware patch have issues regarding data[2]?

Actually I'm wrong.
You did: *(skb->data + 1), which works.
I did: skb->data[1], which does not.
I thought that my mistake was related to data being a void *, but it's
a char * so both should work. I don't know why it failed, maybe my
attention level was too low and I missed something else.

> > Anyway, this patch works, I've tested it by:
> > - associating a device (an Arduino Nano running Zephyr, btw)
> > - having the atusb disassociating the nano successfully (trac = 0)
> > - reassociating the nano
> > - powering off the nano
> > - trying to disassociate
> >
> > The disassociation notification transmission fails with a TRAC status
> > NO_ACK. So:
> >
> > Tested-by: Miquel Raynal <miquel.raynal@bootlin.com>
> >
> > I still have the filtering thing to improve, I'm not sure I'll have
> > time to do that this week. I need some time to prepare the slides now
> > that the demo works :)
> >  
> 
> ok, no problem. Thanks for testing it. I am happy that if I could help
> you here a little bit.
> 
> - Alex
> 


Thanks,
Miquèl