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serial: sh-sci: remove obsolete latency workaround

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Since the transition to hrtimers there is no more need to set a minimum
RX timeout to work around latency issues.

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Link: https://lore.kernel.org/r/20210415093547.21639-1-uli+renesas@fpond.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ulrich Hecht 2021-04-15 11:35:47 +02:00 committed by Greg Kroah-Hartman
parent 5ffa6e344a
commit f9f5498300
1 changed files with 1 additions and 12 deletions
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13
drivers/tty/serial/sh-sci.c
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@ -2609,21 +2609,10 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios,
udelay(DIV_ROUND_UP(10 * 1000000, baud));
}
/*
* Calculate delay for 2 DMA buffers (4 FIFO).
* See serial_core.c::uart_update_timeout().
* With 10 bits (CS8), 250Hz, 115200 baud and 64 bytes FIFO, the above
* function calculates 1 jiffie for the data plus 5 jiffies for the
* "slop(e)." Then below we calculate 5 jiffies (20ms) for 2 DMA
* buffers (4 FIFO sizes), but when performing a faster transfer, the
* value obtained by this formula is too small. Therefore, if the value
* is smaller than 20ms, use 20ms as the timeout value for DMA.
*/
/* Calculate delay for 2 DMA buffers (4 FIFO). */
s->rx_frame = (10000 * bits) / (baud / 100);
#ifdef CONFIG_SERIAL_SH_SCI_DMA
s->rx_timeout = s->buf_len_rx * 2 * s->rx_frame;
if (s->rx_timeout < 20)
s->rx_timeout = 20;
#endif
if ((termios->c_cflag & CREAD) != 0)