[PATCH 04/26] serial: amba-pl010: drop low-latency workaround

Johan Hovold
2021-04-21T09:55:49Z

Commit 2389b272168c ("[ARM] 4417/1: Serial: Fix AMBA drivers locking")
worked around the infamous low_latency behaviour of
tty_flip_buffer_push() by simply dropping and reacquiring the port lock
in the interrupt handler.

Since commit a9c3f68f3cd8 ("tty: Fix low_latency BUG"),
tty_flip_buffer_push() always schedules a work item to push data to the
line discipline and there's no need to keep any low_latency hacks around.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/tty/serial/amba-pl010.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/drivers/tty/serial/amba-pl010.c b/drivers/tty/serial/amba-pl010.c
index 3f96edfe569c..e744b953ca34 100644
--- a/drivers/tty/serial/amba-pl010.c
+++ b/drivers/tty/serial/amba-pl010.c
@@ -159,9 +159,7 @@ static void pl010_rx_chars(struct uart_amba_port *uap)
ignore_char:
status = readb(uap->port.membase + UART01x_FR);
}
- spin_unlock(&uap->port.lock);
tty_flip_buffer_push(&uap->port.state->port);
- spin_lock(&uap->port.lock);
}

static void pl010_tx_chars(struct uart_amba_port *uap)
--
2.26.3