On Thu, Sep 01, 2022 at 01:06:55PM +0200, Jiri Slaby wrote: > Many serial drivers do the same thing: > * send x_char if set > * keep sending from the xmit circular buffer until either > - the loop reaches the end of the xmit buffer > - TX is stopped > - HW fifo is full > * check for pending characters and: > - wake up tty writers to fill for more data into xmit buffer > - stop TX if there is nothing in the xmit buffer > > The only differences are: > * how to write the character to the HW fifo > * the check of the end condition: > - is the HW fifo full? > - is limit of the written characters reached? > > So unify the above into two helper generators: > * DEFINE_UART_PORT_TX_HELPER_LIMITED() -- it performs the above taking > the written characters limit into account, and > * DEFINE_UART_PORT_TX_HELPER() -- the same as above, except it only > checks the HW readiness, not the characters limit. > > The HW specific operations (as stated as "differences" above) are passed > as arguments to the macros. They are: > * tx_ready() -- returns true if HW can accept more data. > * put_char() -- write a character to the device. > * tx_done() -- when the write loop is done, perform arbitrary action > before potential invocation of ops->stop_tx() happens. > > Note that the above macros are generators. This means the code is > generated in place and the above 3 arguments are "inlined". I.e. no > added penalty by generating call instructions for every single > character. Nor any indirect calls. (As in previous versions of this > patchset.) > > Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> > --- > > Notes: > [v2] instead of a function (uart_port_tx_limit()) in serial_core, > generate these in-place using macros. Thus eliminating "call" > penalty. Much nicer, but: > +#define __DEFINE_UART_PORT_TX_HELPER(name, port, ch, tx_ready, put_char, \ > + tx_done, for_test, for_post, ...) \ Do you really need "port" and "ch" as part of this macro? You always set that to the same thing in your patches, so is it really needed? thanks, greg k-h
