On Mon, Jun 10, 2013 at 10:21:00AM +0100, Srinivas KANDAGATLA wrote:

This patch adds support to ASC (asynchronous serial controller)
driver, which is basically a standard serial driver. This IP is common
across all the ST parts for settop box platforms.

ASC is embedded in ST COMMS IP block. It supports Rx & Tx functionality.
It support all industry standard baud rates.

Your driver is not POSIX compliant.

+		for (; count != 0; count--) {
+			c = asc_in(port, ASC_RXBUF);
+			flag = TTY_NORMAL;
+			port->icount.rx++;
+
+			if (unlikely(c & ASC_RXBUF_FE)) {
+				if (c == ASC_RXBUF_FE) {
+					port->icount.brk++;
+					if (uart_handle_break(port))
+						continue;
+					flag = TTY_BREAK;
+				} else {
+					port->icount.frame++;
+					flag = TTY_FRAME;
+				}
+			} else if (ascport->check_parity &&
+				   unlikely(c & ASC_RXBUF_PE)) {
+				port->icount.parity++;
+				flag = TTY_PARITY;
+			}
+
+			if (uart_handle_sysrq_char(port, c))
+				continue;
+			tty_insert_flip_char(tport, c & 0xff, flag);
+		}
+		if (overrun) {
+			port->icount.overrun++;
+			tty_insert_flip_char(tport, 0, TTY_OVERRUN);
+		}

No support for ignoring error conditions.  No support for ignoring all
input... and:

+static void asc_set_termios(struct uart_port *port, struct ktermios *termios,
+			    struct ktermios *old)
+{
+	struct asc_port *ascport = to_asc_port(port);
+	unsigned int baud;
+	u32 ctrl_val;
+	tcflag_t cflag;
+	unsigned long flags;
+
+	port->uartclk = clk_get_rate(ascport->clk);
+
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
+	cflag = termios->c_cflag;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* read control register */
+	ctrl_val = asc_in(port, ASC_CTL);
+
+	/* stop serial port and reset value */
+	asc_out(port, ASC_CTL, (ctrl_val & ~ASC_CTL_RUN));
+	ctrl_val = ASC_CTL_RXENABLE | ASC_CTL_FIFOENABLE;
+
+	/* reset fifo rx & tx */
+	asc_out(port, ASC_TXRESET, 1);
+	asc_out(port, ASC_RXRESET, 1);
+
+	/* set character length */
+	if ((cflag & CSIZE) == CS7) {
+		ctrl_val |= ASC_CTL_MODE_7BIT_PAR;
+	} else {
+		ctrl_val |= (cflag & PARENB) ?  ASC_CTL_MODE_8BIT_PAR :
+						ASC_CTL_MODE_8BIT;
+	}
+
+	ascport->check_parity = (cflag & PARENB) ? 1 : 0;
+
+	/* set stop bit */
+	ctrl_val |= (cflag & CSTOPB) ? ASC_CTL_STOP_2BIT : ASC_CTL_STOP_1BIT;
+
+	/* odd parity */
+	if (cflag & PARODD)
+		ctrl_val |= ASC_CTL_PARITYODD;
+
+	/* hardware flow control */
+	if ((cflag & CRTSCTS) && ascport->hw_flow_control)
+		ctrl_val |= ASC_CTL_CTSENABLE;

This doesn't reflect those facts back into the termios structure to
indicate that they aren't supported.

Consider using uart_port's ignore and read status masks to implement
the break, framing, parity and overrun checking in your interrupt
handler using the same methodology as drivers like 8250, amba-pl011
etc.  That will help you get these code sequences correct.