Blackfin Serial driver: Fix bug - serial driver in PIO mode cant handle input very quickly
Output as many bytes as possible in PIO tx handler.
This reduce the number of tx interrupts and shorten the delay to handle
rx interrupt. So, rx overrun disappears.
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index ac2a3ef..e059475 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -74,7 +74,6 @@
#else
static void bfin_serial_do_work(struct work_struct *work);
static void bfin_serial_tx_chars(struct bfin_serial_port *uart);
-static void local_put_char(struct bfin_serial_port *uart, char ch);
#endif
static void bfin_serial_mctrl_check(struct bfin_serial_port *uart);
@@ -85,6 +84,9 @@
static void bfin_serial_stop_tx(struct uart_port *port)
{
struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+#ifndef CONFIG_BF54x
+ unsigned short ier;
+#endif
while (!(UART_GET_LSR(uart) & TEMT))
continue;
@@ -100,8 +102,6 @@
UART_PUT_LSR(uart, TFI);
UART_CLEAR_IER(uart, ETBEI);
#else
- unsigned short ier;
-
ier = UART_GET_IER(uart);
ier &= ~ETBEI;
UART_PUT_IER(uart, ier);
@@ -210,23 +210,6 @@
#endif
#ifdef CONFIG_SERIAL_BFIN_PIO
-static void local_put_char(struct bfin_serial_port *uart, char ch)
-{
- unsigned short status;
- int flags = 0;
-
- spin_lock_irqsave(&uart->port.lock, flags);
-
- do {
- status = UART_GET_LSR(uart);
- } while (!(status & THRE));
-
- UART_PUT_CHAR(uart, ch);
- SSYNC();
-
- spin_unlock_irqrestore(&uart->port.lock, flags);
-}
-
static void bfin_serial_rx_chars(struct bfin_serial_port *uart)
{
struct tty_struct *tty = uart->port.info->tty;
@@ -236,8 +219,8 @@
struct pt_regs *regs = get_irq_regs();
#endif
- status = UART_GET_LSR(uart);
ch = UART_GET_CHAR(uart);
+ status = UART_GET_LSR(uart);
uart->port.icount.rx++;
#ifdef CONFIG_KGDB_UART
@@ -337,9 +320,12 @@
return;
}
- local_put_char(uart, xmit->buf[xmit->tail]);
- xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
- uart->port.icount.tx++;
+ while ((UART_GET_LSR(uart) & THRE) && xmit->tail != xmit->head) {
+ UART_PUT_CHAR(uart, xmit->buf[xmit->tail]);
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ uart->port.icount.tx++;
+ SSYNC();
+ }
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uart->port);
@@ -352,21 +338,11 @@
{
struct bfin_serial_port *uart = dev_id;
-#ifdef CONFIG_BF54x
- unsigned short status;
spin_lock(&uart->port.lock);
- status = UART_GET_LSR(uart);
- while ((UART_GET_IER(uart) & ERBFI) && (status & DR)) {
- bfin_serial_rx_chars(uart);
- status = UART_GET_LSR(uart);
- }
- spin_unlock(&uart->port.lock);
-#else
- spin_lock(&uart->port.lock);
- while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_RX_READY)
+ while ((UART_GET_IER(uart) & ERBFI) && (UART_GET_LSR(uart) & DR))
bfin_serial_rx_chars(uart);
spin_unlock(&uart->port.lock);
-#endif
+
return IRQ_HANDLED;
}
@@ -374,21 +350,11 @@
{
struct bfin_serial_port *uart = dev_id;
-#ifdef CONFIG_BF54x
- unsigned short status;
spin_lock(&uart->port.lock);
- status = UART_GET_LSR(uart);
- while ((UART_GET_IER(uart) & ETBEI) && (status & THRE)) {
- bfin_serial_tx_chars(uart);
- status = UART_GET_LSR(uart);
- }
- spin_unlock(&uart->port.lock);
-#else
- spin_lock(&uart->port.lock);
- while ((UART_GET_IIR(uart) & IIR_STATUS) == IIR_TX_READY)
+ if ((UART_GET_IER(uart) & ETBEI) && (UART_GET_LSR(uart) & THRE))
bfin_serial_tx_chars(uart);
spin_unlock(&uart->port.lock);
-#endif
+
return IRQ_HANDLED;
}