From: Johan Hovold <johan@kernel.org>
To: Jiri Slaby <jslaby@suse.cz>
Cc: gregkh@linuxfoundation.org, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org,
Andy Shevchenko <andy.shevchenko@gmail.com>,
Joe Perches <joe@perches.com>
Subject: Re: [PATCH v2 34/35] tty: make tty_get_byte_size available
Date: Mon, 10 May 2021 11:47:14 +0200 [thread overview]
Message-ID: <YJkBIm4IiaZSrSPw@hovoldconsulting.com> (raw)
In-Reply-To: <20210510070054.5397-1-jslaby@suse.cz>
On Mon, May 10, 2021 at 09:00:54AM +0200, Jiri Slaby wrote:
> Many tty drivers contain code to compute bits count depending on termios
> cflags. So extract this code from serial core to a separate tty helper
> function called tty_get_byte_size.
>
> In the next patch, call to this new function will replace many copies of
> this code.
>
> [v2] simplified the code flow as suggested by Joe and Andy
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: Joe Perches <joe@perches.com>
> ---
> drivers/tty/serial/serial_core.c | 30 +++--------------------
> drivers/tty/tty_ioctl.c | 42 ++++++++++++++++++++++++++++++++
> include/linux/tty.h | 2 ++
> 3 files changed, 47 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index d29329eb52f4..b3fc2b02a705 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -334,39 +334,15 @@ void
> uart_update_timeout(struct uart_port *port, unsigned int cflag,
> unsigned int baud)
> {
> - unsigned int bits;
> + unsigned int size;
>
> - /* byte size and parity */
> - switch (cflag & CSIZE) {
> - case CS5:
> - bits = 7;
> - break;
> - case CS6:
> - bits = 8;
> - break;
> - case CS7:
> - bits = 9;
> - break;
> - default:
> - bits = 10;
> - break; /* CS8 */
> - }
> -
> - if (cflag & CSTOPB)
> - bits++;
> - if (cflag & PARENB)
> - bits++;
> -
> - /*
> - * The total number of bits to be transmitted in the fifo.
> - */
> - bits = bits * port->fifosize;
> + size = tty_get_byte_size(cflag, true) * port->fifosize;
>
> /*
> * Figure the timeout to send the above number of bits.
> * Add .02 seconds of slop
> */
> - port->timeout = (HZ * bits) / baud + HZ/50;
> + port->timeout = (HZ * size) / baud + HZ/50;
> }
>
> EXPORT_SYMBOL(uart_update_timeout);
> diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
> index aa9ecc8be990..13acc3decd87 100644
> --- a/drivers/tty/tty_ioctl.c
> +++ b/drivers/tty/tty_ioctl.c
> @@ -300,6 +300,48 @@ int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b)
> }
> EXPORT_SYMBOL(tty_termios_hw_change);
>
> +/**
> + * tty_get_byte_size - get size of a byte
> + * @cflag: termios cflag value
> + * @account_flags: account for start and stop bits, second stop bit (if
> + * set), and parity (if set)
> + *
> + * Get the size of a byte in bits depending on @cflag. Depending on
> + * @account_flags parameter, the result also accounts start and stop bits,
> + * the second stop bit, and parity bit.
> + */
> +unsigned char tty_get_byte_size(unsigned int cflag, bool account_flags)
> +{
> + unsigned char bits;
> +
> + switch (cflag & CSIZE) {
> + case CS5:
> + bits = 5;
> + break;
> + case CS6:
> + bits = 6;
> + break;
> + case CS7:
> + bits = 7;
> + break;
> + case CS8:
> + default:
> + bits = 8;
> + break;
> + }
> +
> + if (!account_flags)
> + return bits;
> +
> + if (cflag & CSTOPB)
> + bits++;
> + if (cflag & PARENB)
> + bits++;
> +
> + return bits + 2;
> +}
> +EXPORT_SYMBOL_GPL(tty_get_byte_size);
This should really be two functions rather than passing a bool argument.
I think naming them
tty_get_word_size()
and
tty_get_frame_size()
would be much more clear than than "byte size" + flag.
I realise that the serial-driver interface only uses a cflag argument,
but I think we should consider passing a pointer to the termios
structure instead.
Johan
next prev parent reply other threads:[~2021-05-10 9:47 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-05 9:18 [PATCH 00/35] tty cleanup for 5.14 Jiri Slaby
2021-05-05 9:18 ` [PATCH 01/35] tty: remove broken r3964 line discipline Jiri Slaby
2021-05-05 9:26 ` Greg KH
2021-05-05 9:18 ` [PATCH 02/35] n_tty: remove n_tty_receive_char wrapper Jiri Slaby
2021-05-05 9:18 ` [PATCH 03/35] n_tty: remove n_tty_receive_char_fast Jiri Slaby
2021-05-05 9:18 ` [PATCH 04/35] n_tty: drop n_tty_receive_buf_fast Jiri Slaby
2021-05-05 9:18 ` [PATCH 05/35] n_tty: drop parmrk_dbl from n_tty_receive_char Jiri Slaby
2021-05-05 9:18 ` [PATCH 06/35] n_tty: move lnext handling Jiri Slaby
2021-05-05 9:19 ` [PATCH 07/35] n_tty: make n_tty_receive_char_special return void Jiri Slaby
2021-05-05 9:19 ` [PATCH 08/35] n_tty: do only one cp dereference in n_tty_receive_buf_standard Jiri Slaby
2021-05-05 9:19 ` [PATCH 09/35] n_tty: invert TTY_NORMAL condition " Jiri Slaby
2021-05-05 9:19 ` [PATCH 10/35] n_tty: remove superfluous return from n_tty_receive_signal_char Jiri Slaby
2021-05-05 9:19 ` [PATCH 11/35] tty: make fp of tty_ldisc_ops::receive_buf{,2} const Jiri Slaby
2021-05-05 9:19 ` [PATCH 12/35] tty: cumulate and document tty_struct::flow* members Jiri Slaby
2021-05-05 9:19 ` [PATCH 13/35] tty: cumulate and document tty_struct::ctrl* members Jiri Slaby
2021-05-05 9:19 ` [PATCH 14/35] tty: set tty_ldisc_ops::num statically Jiri Slaby
2021-05-05 9:19 ` [PATCH 15/35] n_gsm: use goto-failpaths in gsm_init Jiri Slaby
2021-05-05 9:19 ` [PATCH 16/35] tty: make tty_ldisc_ops a param in tty_unregister_ldisc Jiri Slaby
2021-05-05 9:19 ` [PATCH 17/35] tty: drop tty_ldisc_ops::refcount Jiri Slaby
2021-05-05 9:19 ` [PATCH 18/35] tty: no checking of tty_unregister_ldisc Jiri Slaby
2021-05-05 9:19 ` [PATCH 19/35] tty: return void from tty_unregister_ldisc Jiri Slaby
2021-05-05 9:19 ` [PATCH 20/35] ti-st: use goto-failpath in st_core_init Jiri Slaby
2021-05-05 9:19 ` [PATCH 21/35] ti-st: use tty_write_room Jiri Slaby
2021-05-05 9:19 ` [PATCH 22/35] tty: make tty_operations::write_room return uint Jiri Slaby
2021-05-05 9:25 ` Geert Uytterhoeven
2021-05-05 10:34 ` Anton Ivanov
2021-05-05 10:43 ` David Sterba
2021-05-05 11:53 ` Max Filippov
2021-05-05 12:15 ` Alex Elder
2021-05-10 11:27 ` Laurentiu Tudor
2021-05-05 9:19 ` [PATCH 23/35] USB: serial: make usb_serial_driver::write_room " Jiri Slaby
2021-05-19 9:07 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 24/35] tty: make tty_buffer_space_avail " Jiri Slaby
2021-05-05 9:19 ` [PATCH 25/35] tty: remove tty_operations::chars_in_buffer for non-buffering Jiri Slaby
2021-05-05 11:51 ` Max Filippov
2021-05-06 5:47 ` Jiri Slaby
2021-05-06 5:56 ` Greg KH
2021-05-05 9:19 ` [PATCH 26/35] tty: make tty_operations::chars_in_buffer return uint Jiri Slaby
2021-05-05 10:34 ` Anton Ivanov
2021-05-05 10:43 ` David Sterba
2021-05-05 9:19 ` [PATCH 27/35] serial: make usb_serial_driver::chars_in_buffer " Jiri Slaby
2021-05-19 9:09 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 28/35] nozomi: simplify ntty_chars_in_buffer Jiri Slaby
2021-05-05 9:19 ` [PATCH 29/35] USB: serial: digi_acceleport, simplify digi_chars_in_buffer Jiri Slaby
2021-05-19 9:11 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 30/35] tty: remove empty tty_operations::flush_buffer Jiri Slaby
2021-05-05 9:19 ` [PATCH 31/35] tty: remove empty tty_operations::set_termios Jiri Slaby
2021-05-05 10:34 ` Anton Ivanov
2021-05-05 9:19 ` [PATCH 32/35] isdn: capi, remove optional tty ops Jiri Slaby
2021-05-05 9:19 ` [PATCH 33/35] isdn: capi, drop useless pr_debugs Jiri Slaby
2021-05-05 9:19 ` [PATCH 34/35] tty: make tty_get_byte_size available Jiri Slaby
2021-05-06 7:16 ` Joe Perches
2021-05-06 7:19 ` Jiri Slaby
[not found] ` <CAHp75Vfq6ABW7ukwaKmZOF2DszmuHD28S=wcLcFowvRdXTnWmg@mail.gmail.com>
2021-05-06 8:31 ` Jiri Slaby
2021-05-06 9:33 ` Andy Shevchenko
2021-05-06 8:35 ` Joe Perches
2021-05-10 7:00 ` [PATCH v2 " Jiri Slaby
2021-05-10 9:47 ` Johan Hovold [this message]
2021-05-13 7:24 ` Jiri Slaby
2021-05-13 9:41 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 35/35] tty: make use of tty_get_byte_size Jiri Slaby
2021-05-10 9:59 ` Johan Hovold
2021-05-13 15:04 ` [PATCH 00/35] tty cleanup for 5.14 Greg KH
2021-05-13 16:20 ` Johan Hovold
2021-05-13 16:29 ` Greg KH
2021-05-14 8:11 ` Johan Hovold
2021-06-10 9:02 ` [PATCH v3 1/4] tty: make tty_get_{char,frame}_size available Jiri Slaby
2021-06-10 9:02 ` [PATCH v3 2/4] mxs-auart: redefine AUART_LINECTRL_WLEN to accept bits count Jiri Slaby
2021-06-10 9:02 ` [PATCH v3 3/4] cypress_m8: switch data_bits to real character bits Jiri Slaby
2021-06-10 9:02 ` [PATCH v3 4/4] tty: make use of tty_get_{char,frame}_size Jiri Slaby
2021-06-10 15:15 ` Alex Elder
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