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author | Peter Hurley <peter@hurleysoftware.com> | 2014-10-16 16:54:18 -0400 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-05 18:53:54 -0800 |
commit | 479e9b94fdce7bc46f669831012fc12f56696fd7 (patch) | |
tree | e51d28533aa68a3234e0ce4a6f21bb5b59417997 /drivers/tty/serial/atmel_serial.c | |
parent | 86c80a8e2ab443e9c4261b3499de4ce808399104 (diff) | |
download | op-kernel-dev-479e9b94fdce7bc46f669831012fc12f56696fd7.zip op-kernel-dev-479e9b94fdce7bc46f669831012fc12f56696fd7.tar.gz |
serial: Refactor uart_flush_buffer() from uart_close()
In the context of the final tty & port close, flushing the tx
ring buffer after the hardware has already been shutdown and
the ring buffer freed is neither required nor desirable.
uart_flush_buffer() performs 3 operations:
1. Resets tx ring buffer indices, but the tx ring buffer has
already been freed and the indices are reset if the port is
re-opened.
2. Calls uart driver's flush_buffer() method
5 in-tree uart drivers define flush_buffer() methods:
amba-pl011, atmel-serial, imx, serial-tegra, timbuart
These have been refactored into the shutdown() method, if
required.
3. Kicks the ldisc for more writing, but this is undesirable.
The file handle is being released; any waiting writer will
will be kicked out by tty_release() with a warning. Further,
the N_TTY ldisc may generate SIGIO for a file handle which
is no longer valid.
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/atmel_serial.c')
-rw-r--r-- | drivers/tty/serial/atmel_serial.c | 28 |
1 files changed, 15 insertions, 13 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index edde3ec..8a84034 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1802,6 +1802,20 @@ free_irq: } /* + * Flush any TX data submitted for DMA. Called when the TX circular + * buffer is reset. + */ +static void atmel_flush_buffer(struct uart_port *port) +{ + struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); + + if (atmel_use_pdc_tx(port)) { + UART_PUT_TCR(port, 0); + atmel_port->pdc_tx.ofs = 0; + } +} + +/* * Disable the port */ static void atmel_shutdown(struct uart_port *port) @@ -1852,20 +1866,8 @@ static void atmel_shutdown(struct uart_port *port) atmel_free_gpio_irq(port); atmel_port->ms_irq_enabled = false; -} -/* - * Flush any TX data submitted for DMA. Called when the TX circular - * buffer is reset. - */ -static void atmel_flush_buffer(struct uart_port *port) -{ - struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); - - if (atmel_use_pdc_tx(port)) { - UART_PUT_TCR(port, 0); - atmel_port->pdc_tx.ofs = 0; - } + atmel_flush_buffer(port); } /* |