Let's have more orthogonal and cleaner API, where buffers are
configured by tty_set_rx_buf/tty_set_tx_buf, and only them. It
means that newly initialized tty starts in unbuffered mode, which
is somewhat a sidestep from a main usecase behind tty, which is
buffered operation, but again, having a cleaner API (and good
docs, explaining users how it should be and what they should do)
prevails.
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
The whole "tty" concept is conceived around efficient
interrupt-driven operation. However, it's beneficial to add
non interupt-driven operation under the same API:
1. Wider usecase coverage in general.
2. Allows to use the same familiar API (based on POSIX concepts)
even for UART implementations without interrupt support.
3. Allows to switch operation dynamically based on the needs.
For example, if the system is in degraded mode and interrupt
handling cannot be trusted/disabled, allows to still output
diagnostic information to user. This was the original motivation
to provide such a mode, to support logging subsystem's "panic"
mode.
To implement this feature, tty_set_rx_buf() and tty_set_tx_buf()
functions are provided, allowing to reconfigure buffers used
dynamically. If configured buffer length is 0, the operation
switched to unbuffered.
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
To be properly layered.
This call is used to signal to user an input buffer overload. Take
a chance to output just a single character in this case, to avoid
amplification and possible output buffer overflow either.
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
This patch proceeds with the separation of older serial console
subsystem into device-independent console subsytem and buffered
serial device ("tty") API.
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Tty device gets only read/write calls, but console retains
getchar/putchar for convenience.
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Previously, transmit was effectively non-blocking - a character either
went into buffer, or -1 was returned. Now it's possible to block if
buffer is full. Timeout is K_FOREVER by default, can be adjusted
with tty_set_tx_timeout() (similar to receive timeout).
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
This allows to specify receive timeout, instead of previously
hardcoded K_FOREVER value. K_FOREVER is still the default, and can
be changes after tty initialization using tty_set_rx_timeout() call,
and timeout is stored as a property of tty. (Instead of e.g. being
a param of each receive call. Handling like that is required for
POSIX-like behavior of tty).
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
Before going further for API refactoring in console subsys, makes
sense to split "tty" implementation from "console" implementation,
to make it clearer that "console" is just a "tty" instantiated on
a particular UART device.
Signed-off-by: Paul Sokolovsky <paul.sokolovsky@linaro.org>
