Re: [RFC PATCH 0/3] UART slave device bus

One Thousand Gnomes
2016-08-26T13:13:01Z

> Either we'd have to call tty_port->rx a character at a time or
> implement some temporary buffer. I don't think we want to call things
> like BT receive code a byte at a time. This needs to be a layer
> higher. flush_to_ldisc either needs to be duplicated to handle
> tty_port->rx or generalized to call either tty_port->rx or ldisc
> receive_buf. I'm not sure what to do about ldisc ref counting in the
> latter case.

You already have the buffer

What I was trying to suggest was that instead of

chars->buffer
flush
workqueue
loop pushing data into the ldisc

You can also do

chars->buffer
flush
workqueue
->rx() [where flush_to_ldisc is just one implementation of ->rx]

For byte by byte ports it really makes no difference (except you would be
able to do processing without an ldisc), but for DMA devices it would
give us a faster path for processing since the DMA completion event can
simply fire a buffer a characters directly at the protocol handler where
there are not latency concerns (ie it starts the new DMA and directly
involves ->rx())

Alan