The counts in tty_port_client_operations hooks' are currently
represented by all 'int', 'unsigned int', and 'size_t'. Unify them all
to unsigned 'size_t' for clarity. Note that size_t is used already in
tty_buffer.c. So, eventually, it is spread for counts everywhere and
this is the beginning.
So the two changes namely:
* ::receive_buf() is called from tty_ldisc_receive_buf(). And that
expects values ">= 0" from ::receive_buf(), so switch its rettype to
size_t is fine. tty_ldisc_receive_buf() types will be changed
separately.
* ::lookahead_buf()'s count comes from lookahead_bufs() and is already
'unsigned int'.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230810091510.13006-11-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The parameters are already unsigned chars. So make them explicitly u8s,
as the rest is going to be unified to u8 eventually too.
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230810091510.13006-10-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert various parameter names for ->dtr_rts() and related functions
from onoff, on, and raise to active.
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230117090358.4796-12-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert the raise/on parameter in ->dtr_rts() to bool through the
callchain. The parameter is used like bool. In USB serial, there
remains a few implicit bool -> larger type conversions because some
devices use u8 in their control messages.
In moxa_tiocmget(), dtr variable was reused for line status which
requires int so use a separate variable for status.
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230117090358.4796-8-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Return boolean from ->carrier_raised() instead of 0 and 1. Make the
return type change also to tty_port_carrier_raised() that makes the
->carrier_raised() call (+ cd variable in moxa into which its return
value is stored).
Also cleans up a few unnecessary constructs related to this change:
return xx ? 1 : 0;
-> return xx;
if (xx)
return 1;
return 0;
-> return xx;
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20230117090358.4796-7-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When tty is not read from, XON/XOFF may get stuck into an
intermediate buffer. As those characters are there to do software
flow-control, it is not very useful. In the case where neither end
reads from ttys, the receiving ends might not be able receive the
XOFF characters and just keep sending more data to the opposite
direction. This problem is almost guaranteed to occur with DMA
which sends data in large chunks.
If TTY is slow to process characters, that is, eats less than given
amount in receive_buf, invoke lookahead for the rest of the chars
to process potential XON/XOFF characters.
We need to keep track of how many characters have been processed by the
lookahead to avoid processing the flow control char again on the normal
path. Bookkeeping occurs parallel on two layers (tty_buffer and n_tty)
to avoid passing the lookahead_count through the whole call chain.
When a flow-control char is processed, two things must occur:
a) it must not be treated as normal char
b) if not yet processed, flow-control actions need to be taken
The return value of n_tty_receive_char_flow_ctrl() tells caller a), and
b) is kept internal to n_tty_receive_char_flow_ctrl().
If characters were previous looked ahead, __receive_buf() makes two
calls to the appropriate n_tty_receive_buf_* function. First call is
made with lookahead_done=true for the characters that were subject to
lookahead earlier and then with lookahead=false for the new characters.
Either of the calls might be skipped when it has no characters to
handle.
Reported-by: Gilles Buloz <gilles.buloz@kontron.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606153652.63554-2-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Define a kfifo inside struct tty_port. We use DECLARE_KFIFO_PTR and let
the preexisting tty_port::xmit_buf be also the buffer for the kfifo.
And handle the initialization/decomissioning along with xmit_buf, i.e.
in tty_port_alloc_xmit_buf() and tty_port_free_xmit_buf(), respectively.
This allows for kfifo use in drivers which opt-in, while others still
may use the old xmit_buf. mxser will be the first user in the next
few patches.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20220124071430.14907-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_port_operations used to have only comments along its members.
Convert them into proper kernel-doc comments in front of the structure.
And add some more explanation to them where needed.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_port used to have only short comments along its members. Convert
them into proper kernel-doc comments in front of the structure. And add
some more explanation to them where needed.
The whole structure purpose and handling is documented at the end too --
some pieces of preexisting text moved to this place.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211126081611.11001-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty.h is long enough already. And I am slowly adding kernel-doc
documentation, so it grows to unmaintainable long mess. To avoid this,
split tty.h further into tty_port.h and move there tty_port-related
declarations and function prototypes (those implemented in tty_port.c).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Jiri Slaby (SUSE)