On Mon, Aug 10, 2015 at 1:54 PM, Lee Jones <lee.jones@xxxxxxxxxx> wrote: > On Mon, 10 Aug 2015, Jassi Brar wrote: >> On Mon, Jul 27, 2015 at 3:14 PM, Lee Jones <lee.jones@xxxxxxxxxx> wrote: >> > This header is currently only used for defines pertaining to data >> > direction i.e. Rx, Tx or Loopback. >> > >> > Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> >> > --- >> > include/dt-bindings/mailbox/mailbox.h | 14 ++++++++++++++ >> > 1 file changed, 14 insertions(+) >> > create mode 100644 include/dt-bindings/mailbox/mailbox.h >> > >> > diff --git a/include/dt-bindings/mailbox/mailbox.h b/include/dt-bindings/mailbox/mailbox.h >> > new file mode 100644 >> > index 0000000..82e929a >> > --- /dev/null >> > +++ b/include/dt-bindings/mailbox/mailbox.h >> > @@ -0,0 +1,14 @@ >> > +/* >> > + * This program is free software; you can redistribute it and/or modify >> > + * it under the terms of the GNU General Public License version 2 as >> > + * published by the Free Software Foundation. >> > + */ >> > + >> > +#ifndef __MAILBOX_CONTROLLER_DT_BINDINGS_H >> > +#define __MAILBOX_CONTROLLER_DT_BINDINGS_H >> > + >> > +#define MBOX_TX 0x1 >> > +#define MBOX_RX 0x2 >> > +#define MBOX_LOOPBACK (MBOX_RX | MBOX_TX) >> > + >> Not sure I understand 'loopback'. Does it mean h/w has some >> 'loopback' mode for testing purposes? Or it simply means the >> controller can send as well as receive messages? > > 'loopback' allows firmware to conduct some early function tests. > However, channels are simplex, so we provide protection against > multiple allocation of single channel. By allocating a LOOPBACK > channel we over-ride this protection and allow a single channel to be > allocated twice, once for Rx and the other for Tx. > So basically hardware is half-duplex, not simplex. I think maybe you should simply allow for RX and TX always. It should work. Just handover any received data before send_data (reflecting the h/w limitation). That way you don't need any such special flag. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
