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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 | |
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is no longer valid.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>
-rw-r--r-- | drivers/tty/serial/amba-pl011.c | 1 | ||||
-rw-r--r-- | drivers/tty/serial/atmel_serial.c | 28 | ||||
-rw-r--r-- | drivers/tty/serial/serial-tegra.c | 30 | ||||
-rw-r--r-- | drivers/tty/serial/serial_core.c | 1 | ||||
-rw-r--r-- | drivers/tty/serial/timbuart.c | 2 |
5 files changed, 34 insertions, 28 deletions
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 02016fc..8469b66 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -1689,6 +1689,7 @@ static void pl011_shutdown(struct uart_port *port) plat->exit(); } + pl011_dma_flush_buffer(port); } static void 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); } /* diff --git a/drivers/tty/serial/serial-tegra.c b/drivers/tty/serial/serial-tegra.c index 53d7c31..78a5cf6 100644 --- a/drivers/tty/serial/serial-tegra.c +++ b/drivers/tty/serial/serial-tegra.c @@ -1034,6 +1034,20 @@ fail_rx_dma: return ret; } +/* + * Flush any TX data submitted for DMA and PIO. Called when the + * TX circular buffer is reset. + */ +static void tegra_uart_flush_buffer(struct uart_port *u) +{ + struct tegra_uart_port *tup = to_tegra_uport(u); + + tup->tx_bytes = 0; + if (tup->tx_dma_chan) + dmaengine_terminate_all(tup->tx_dma_chan); + return; +} + static void tegra_uart_shutdown(struct uart_port *u) { struct tegra_uart_port *tup = to_tegra_uport(u); @@ -1046,6 +1060,8 @@ static void tegra_uart_shutdown(struct uart_port *u) tegra_uart_dma_channel_free(tup, true); tegra_uart_dma_channel_free(tup, false); free_irq(u->irq, tup); + + tegra_uart_flush_buffer(u); } static void tegra_uart_enable_ms(struct uart_port *u) @@ -1174,20 +1190,6 @@ static void tegra_uart_set_termios(struct uart_port *u, return; } -/* - * Flush any TX data submitted for DMA and PIO. Called when the - * TX circular buffer is reset. - */ -static void tegra_uart_flush_buffer(struct uart_port *u) -{ - struct tegra_uart_port *tup = to_tegra_uport(u); - - tup->tx_bytes = 0; - if (tup->tx_dma_chan) - dmaengine_terminate_all(tup->tx_dma_chan); - return; -} - static const char *tegra_uart_type(struct uart_port *u) { return TEGRA_UART_TYPE; diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 1166c52..787d67f 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1361,7 +1361,6 @@ static void uart_close(struct tty_struct *tty, struct file *filp) mutex_lock(&port->mutex); uart_shutdown(tty, state); - uart_flush_buffer(tty); tty_ldisc_flush(tty); diff --git a/drivers/tty/serial/timbuart.c b/drivers/tty/serial/timbuart.c index 0d11d50..e9e2523 100644 --- a/drivers/tty/serial/timbuart.c +++ b/drivers/tty/serial/timbuart.c @@ -273,6 +273,8 @@ static void timbuart_shutdown(struct uart_port *port) dev_dbg(port->dev, "%s\n", __func__); free_irq(port->irq, uart); iowrite32(0, port->membase + TIMBUART_IER); + + timbuart_flush_buffer(port); } static int get_bindex(int baud) |