diff options
Diffstat (limited to 'packages/linux/linux-2.6.18/add-flush_buffer-operation-to-uart_ops.patch')
| -rw-r--r-- | packages/linux/linux-2.6.18/add-flush_buffer-operation-to-uart_ops.patch | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/packages/linux/linux-2.6.18/add-flush_buffer-operation-to-uart_ops.patch b/packages/linux/linux-2.6.18/add-flush_buffer-operation-to-uart_ops.patch new file mode 100644 index 0000000000..0c9b919900 --- /dev/null +++ b/packages/linux/linux-2.6.18/add-flush_buffer-operation-to-uart_ops.patch @@ -0,0 +1,71 @@ +From nobody Mon Sep 17 00:00:00 2001 +From: Håvard Skinnemoen <hskinnemoen@atmel.com> +Date: Thu Feb 2 15:48:50 2006 +0100 +Subject: [PATCH] Add flush_buffer() operation to uart_ops + +Serial drivers using DMA (like the Atmel USART3 driver) tend to get +very confused when the xmit buffer is flushed and nobody told them. +They also tend to spew a lot of garbage since the DMA engine keeps +running after the buffer is flushed and possibly refilled with +unrelated data. + +This patch adds a new flush_buffer operation to the uart_ops struct, +along with a call to it from uart_flush_buffer() right after the xmit +buffer has been cleared. The driver can implement this in order to +syncronize its internal DMA state with the xmit buffer when the buffer +is flushed. + +--- + + Documentation/serial/driver | 11 +++++++++++ + drivers/serial/serial_core.c | 2 ++ + include/linux/serial_core.h | 1 + + 3 files changed, 14 insertions(+) + +Index: linux-2.6.16-avr32/Documentation/serial/driver +=================================================================== +--- linux-2.6.16-avr32.orig/Documentation/serial/driver 2006-03-20 06:53:29.000000000 +0100 ++++ linux-2.6.16-avr32/Documentation/serial/driver 2006-04-03 18:57:11.000000000 +0200 +@@ -186,6 +186,17 @@ hardware. + Locking: port_sem taken. + Interrupts: caller dependent. + ++ flush_buffer(port) ++ Flush any write buffers, reset any DMA state and stop any ++ ongoing DMA transfers. ++ ++ This will be called whenever the port->info->xmit circular ++ buffer is cleared. ++ ++ Locking: port->lock taken. ++ Interrupts: locally disabled. ++ This call must not sleep ++ + set_termios(port,termios,oldtermios) + Change the port parameters, including word length, parity, stop + bits. Update read_status_mask and ignore_status_mask to indicate +Index: linux-2.6.16-avr32/drivers/serial/serial_core.c +=================================================================== +--- linux-2.6.16-avr32.orig/drivers/serial/serial_core.c 2006-03-20 06:53:29.000000000 +0100 ++++ linux-2.6.16-avr32/drivers/serial/serial_core.c 2006-04-03 18:57:11.000000000 +0200 +@@ -556,6 +556,8 @@ static void uart_flush_buffer(struct tty + + spin_lock_irqsave(&port->lock, flags); + uart_circ_clear(&state->info->xmit); ++ if (port->ops->flush_buffer) ++ port->ops->flush_buffer(port); + spin_unlock_irqrestore(&port->lock, flags); + tty_wakeup(tty); + } +Index: linux-2.6.16-avr32/include/linux/serial_core.h +=================================================================== +--- linux-2.6.16-avr32.orig/include/linux/serial_core.h 2006-03-20 06:53:29.000000000 +0100 ++++ linux-2.6.16-avr32/include/linux/serial_core.h 2006-04-03 18:57:11.000000000 +0200 +@@ -164,6 +164,7 @@ struct uart_ops { + void (*break_ctl)(struct uart_port *, int ctl); + int (*startup)(struct uart_port *); + void (*shutdown)(struct uart_port *); ++ void (*flush_buffer)(struct uart_port *); + void (*set_termios)(struct uart_port *, struct termios *new, + struct termios *old); + void (*pm)(struct uart_port *, unsigned int state, |