This allows drivers (such as OMAP serial) to allocate and free their
transmit buffers in a sane manner, rather than working around the
buffer allocation provided by serial_core.
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 23 ++++++++++++++++-------
include/linux/serial_core.h | 2 ++
2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 4dd609e..53274ae 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -147,12 +147,18 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
* buffer.
*/
if (!state->xmit.buf) {
- /* This is protected by the per port mutex */
- page = get_zeroed_page(GFP_KERNEL);
- if (!page)
- return -ENOMEM;
+ if (uport->ops->alloc_xmit) {
+ retval = uport->ops->alloc_xmit(uport, &state->xmit);
+ if (retval)
+ return retval;
+ } else {
+ /* This is protected by the per port mutex */
+ page = get_zeroed_page(GFP_KERNEL);
+ if (!page)
+ return -ENOMEM;
- state->xmit.buf = (unsigned char *) page;
+ state->xmit.buf = (unsigned char *) page;
+ }
uart_circ_clear(&state->xmit);
}
@@ -257,7 +263,10 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
* Free the transmit buffer page.
*/
if (state->xmit.buf) {
- free_page((unsigned long)state->xmit.buf);
+ if (uport->ops->free_xmit)
+ uport->ops->free_xmit(uport, &state->xmit);
+ else
+ free_page((unsigned long)state->xmit.buf);
state->xmit.buf = NULL;
}
}
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index b17d4c9..ebe9af1 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -248,6 +248,8 @@ struct uart_ops {
void (*break_ctl)(struct uart_port *, int ctl);
int (*startup)(struct uart_port *);
void (*shutdown)(struct uart_port *);
+ int (*alloc_xmit)(struct uart_port *, struct circ_buf *);
+ void (*free_xmit)(struct uart_port *, struct circ_buf *);
void (*flush_buffer)(struct uart_port *);
void (*set_termios)(struct uart_port *, struct ktermios *new,
struct ktermios *old);
--
1.7.4.4
--
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