Hello, Samuel Thibault, on dim. 26 févr. 2017 03:48:32 +0100, wrote: > Samuel Thibault, on dim. 26 févr. 2017 02:50:05 +0100, wrote: > > Please note in your todo for the input part, that ttyio will have to > > call read_buff_add for each received character, when that method is > > not NULL (that's actually the only driver using it, so we will really > > need a tester for this exact driver). > > More precisely, it's the spk_ttyio_ldisc_ops->receive_buf2 method which > should call read_buff_add for each received character. > > > The step further will be implementing spk_ttyio_in and > spk_ttyio_in_nowait. I believe the easiest way is the following: I forgot the part that stops the tty layer from sending characters: > - define an spk_ldisc_data structure containing just one character (buf), > and a semaphore. and one int (buf_free). > - on ldisc_open, allocate a pointer to such structure, set > tty->disc_data to point to it, and initialized the semaphore to 0 > tokens. and initialize buf_free to 1. > - in the receive_buf2 method, > - if read_buff_add is defined, just call it for each character and be > done > - otherwise, store the first received character in > ((struct spk_ldisc_data *)tty->disc_data)->buf > , call up() on the semaphore, and return 1 (to tell that you ate the > character). Here, *just before* storing the character in buf, check buf_free: if it is 0, return 0. otherwise, call mb(), and continue with what I wrote above. > - in spk_serial_in, call down_timeout(usecs_to_jiffies(SPK_SERIAL_TIMEOUT)), > - on success, copy the character stored in buf, then call tty_schedule_flip() and return the copy > - on failure (timed out), return 0xff. > > - in spk_serial_in_nowait, call down_trylock(), > - on success, copy the character stored in buf, then call tty_schedule_flip() and return the copy > - on failure, return 0. In each case, right after the copy, call mb() and set buf_free to 1. Actually, these two function could be factorized to just one, which takes a long timeout parameter (in jiffies) and returns an int instead of a char, and uses down_trylock when the timeout is 0 and down_timeout otherwise, and returns -1 instead of 0 on failure. And then make spk_serial_in use it and return 0xff when getting -1, and make spk_serial_in_nowait return 0 when getting -1. Cleaning that returned value convention can be another patch later. Samuel _______________________________________________ Speakup mailing list Speakup@xxxxxxxxxxxxxxxxx http://linux-speakup.org/cgi-bin/mailman/listinfo/speakup
