[UART] keep the afe enabled in interrupt handler
do not disable autoflow control in BT recieve interrupt handler.
though we re-enable it at watermark of 150 bytes,
this should avoid and be at a safer side for fifo overrun corner cases.
[bug: 17870872]
Change-Id: I4b34f6dd3680d1a88f31fe0afa9effff838d8b15
Signed-off-by: oza pawandeep <oza@broadcom.com>
diff --git a/drivers/tty/serial/8250/8250_brcm_bt.c b/drivers/tty/serial/8250/8250_brcm_bt.c
index a05018f..2de2f3c 100644
--- a/drivers/tty/serial/8250/8250_brcm_bt.c
+++ b/drivers/tty/serial/8250/8250_brcm_bt.c
@@ -32,15 +32,6 @@
int n_fifo;
int mcr;
- /* Check whether Auto Flow control is enable in Modem control register
- * */
- mcr = port->serial_in(port, UART_MCR);
- if (mcr & UART_MCR_AFE) {
- afe_status = 1;
- /* Disabling Auto flow control */
- port->serial_out(port, UART_MCR, mcr & (~UART_MCR_AFE));
- }
-
/* Handle port gets called from either the interrupt context
* _OR_ from the timeout thread context (serial8250_timeout).
*
@@ -120,36 +111,11 @@
flag = TTY_FRAME;
}
- if (afe_status) {
- /* Re-enable AFE if FIFO level go up. (this is not
- * common)*/
- n_fifo = port->serial_in(port, UART_RX_FIFO_LEVEL);
- /* FIXME: Currently this is added as a workaround for
- * BT throughput. Received data available interrpt is
- * generated when FIFO is Half full.
- * Making sure we have enough time to clear the fifo by
- * initially disabling the auto flow control. When FIFO
- * has more than 150 bytes, enable the auto flow
- * control so that we dont run into overrun condition.
- * */
- if (n_fifo >= 150) {
- mcr = port->serial_in(port, UART_MCR);
- port->serial_out(port, UART_MCR, mcr | (UART_MCR_AFE));
- afe_status = 0;
- }
- }
-
uart_insert_char(&up->port, lsr, UART_LSR_OE, ch, flag);
ignore_char:
lsr = port->serial_in(port, UART_LSR);
} while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (max_count-- > 0));
- /* Keep the Auto flow control to its pervious state.*/
- if (afe_status) {
- /* MUST enable AFE when exit this routine */
- mcr = port->serial_in(port, UART_MCR);
- port->serial_out(port, UART_MCR, mcr | (UART_MCR_AFE));
- }
spin_unlock(&up->port.lock);
tty_flip_buffer_push(&port->state->port);
spin_lock(&up->port.lock);
