Three character device interfaces is a crowd

[Jiri Svoboda]

Currently there are three different character device interfaces in use by different drivers:

• uspace/lib/c/include/ipc/char.h (s3c24xx_uart)
• uspace/lib/c/include/ipc/chardev.h (pl050, i8042)
• uspace/lib/drv/include/ops/char_dev.h (ns8250, test1)

Each interface has different pros and cons (both in terms of API and implementation).

• char.h is can only transfer one byte at a time, but has asynchronous reception
• chardev.h has full client/server library wrappers (chardev_srv.c/chardev.c), it can only transfer a few bytes at a time
• char_dev.h can transfer up to 256 bytes using internal buffers whose size cannot be configured; it requires devman method dispatcher

Ultimately we should have a single interface, hopefully better than each of those we currently have.

[Jiri Svoboda]

Note that ns8250 also implements implements methods from ipc/serial_ctl.h so it actually sort of implements two interfaces.

[Jiri Svoboda]

Fixed. See mainly

• ​commit ipc/char.h -> chardev
• ​char_dev_iface -> chardev