Subject: serial: Add circular buffer helpers
Add some helper macros to neaten things up a little in the serial
drivers.
Signed-off-by: Corey Minyard <minyard@xxxxxxx>
drivers/serial/8250.c | 7 ++++---
include/linux/serial_core.h | 2 ++
2 files changed, 6 insertions(+), 3 deletions(-)
Index: linux-2.6.21/drivers/serial/8250.c
===================================================================
--- linux-2.6.21.orig/drivers/serial/8250.c
+++ linux-2.6.21/drivers/serial/8250.c
@@ -1265,7 +1265,7 @@ static int receive_chars(struct uart_825
static int transmit_chars(struct uart_8250_port *up)
{
- struct circ_buf *xmit = &up->port.info->xmit;
+ struct circ_buf *xmit = uart_get_circ_buf(&up->port);
int count;
int xmit_ready = 0;
@@ -1287,7 +1287,7 @@ static int transmit_chars(struct uart_82
count = up->tx_loadsz;
do {
serial_out(up, UART_TX, xmit->buf[xmit->tail]);
- xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ xmit->tail = uart_wrap_circ_buf(xmit->tail + 1);
up->port.icount.tx++;
if (uart_circ_empty(xmit))
break;
@@ -1507,6 +1507,7 @@ static void serial8250_timeout(unsigned
static void serial8250_backup_timeout(unsigned long data)
{
struct uart_8250_port *up = (struct uart_8250_port *)data;
+ struct circ_buf *xmit = uart_get_circ_buf(&up->port);
unsigned int iir, ier = 0;
/*
@@ -1527,7 +1528,7 @@ static void serial8250_backup_timeout(un
* ia64 and parisc boxes.
*/
if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
- (!uart_circ_empty(&up->port.info->xmit) || up->port.x_char) &&
+ (!uart_circ_empty(xmit) || up->port.x_char) &&
(serial_in(up, UART_LSR) & UART_LSR_THRE)) {
iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
iir |= UART_IIR_THRI;
Index: linux-2.6.21/include/linux/serial_core.h
===================================================================
--- linux-2.6.21.orig/include/linux/serial_core.h
+++ linux-2.6.21/include/linux/serial_core.h
@@ -398,6 +398,8 @@ int uart_resume_port(struct uart_driver
#define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
#define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
+#define uart_get_circ_buf(port) (&(port)->info->xmit)
+#define uart_wrap_circ_buf(val) ((val) & (UART_XMIT_SIZE - 1))
#define uart_circ_chars_pending(circ) \
(CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
-
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