TTY/Serial fixes for 6.8-rc8 (or -final)

Here are some small remaining tty/serial driver fixes for 6.8-rc8.
 Included in here is fixes for:
   - vt unicode buffer corruption fix
   - imx serial driver fixes, again
   - port suspend fix
   - 8250_dw driver fix
   - fsl_lpuart driver fix
   - revert for the qcom_geni_serial driver to fix a reported regression
 
 All of these have been in linux-next with no reported issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-6.8-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty / serial fixes from Greg KH:
 "Here are some small remaining tty/serial driver fixes. Included in
  here is fixes for:

   - vt unicode buffer corruption fix

   - imx serial driver fixes, again

   - port suspend fix

   - 8250_dw driver fix

   - fsl_lpuart driver fix

   - revert for the qcom_geni_serial driver to fix a reported regression

  All of these have been in linux-next with no reported issues"

* tag 'tty-6.8-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  Revert "tty: serial: simplify qcom_geni_serial_send_chunk_fifo()"
  tty: serial: fsl_lpuart: avoid idle preamble pending if CTS is enabled
  vt: fix unicode buffer corruption when deleting characters
  serial: port: Don't suspend if the port is still busy
  serial: 8250_dw: Do not reclock if already at correct rate
  tty: serial: imx: Fix broken RS485

drivers/tty/serial/8250/8250_dw.c

@@ -357,9 +357,9 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
 	long rate;
 	int ret;
 
-	clk_disable_unprepare(d->clk);
 	rate = clk_round_rate(d->clk, newrate);
-	if (rate > 0) {
+	if (rate > 0 && p->uartclk != rate) {
+		clk_disable_unprepare(d->clk);
 		/*
 		 * Note that any clock-notifer worker will block in
 		 * serial8250_update_uartclk() until we are done.
@@ -367,8 +367,8 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
 		ret = clk_set_rate(d->clk, newrate);
 		if (!ret)
 			p->uartclk = rate;
+		clk_prepare_enable(d->clk);
 	}
-	clk_prepare_enable(d->clk);
 
 	dw8250_do_set_termios(p, termios, old);
 }

drivers/tty/serial/fsl_lpuart.c

@@ -2345,9 +2345,12 @@ lpuart32_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	lpuart32_write(&sport->port, bd, UARTBAUD);
 	lpuart32_serial_setbrg(sport, baud);
-	lpuart32_write(&sport->port, modem, UARTMODIR);
-	lpuart32_write(&sport->port, ctrl, UARTCTRL);
+	/* disable CTS before enabling UARTCTRL_TE to avoid pending idle preamble */
+	lpuart32_write(&sport->port, modem & ~UARTMODIR_TXCTSE, UARTMODIR);
 	/* restore control register */
+	lpuart32_write(&sport->port, ctrl, UARTCTRL);
+	/* re-enable the CTS if needed */
+	lpuart32_write(&sport->port, modem, UARTMODIR);
 
 	if ((ctrl & (UARTCTRL_PE | UARTCTRL_M)) == UARTCTRL_PE)
 		sport->is_cs7 = true;

drivers/tty/serial/imx.c

@@ -462,8 +462,7 @@ static void imx_uart_stop_tx(struct uart_port *port)
 	}
 }
 
-/* called with port.lock taken and irqs off */
-static void imx_uart_stop_rx(struct uart_port *port)
+static void imx_uart_stop_rx_with_loopback_ctrl(struct uart_port *port, bool loopback)
 {
 	struct imx_port *sport = (struct imx_port *)port;
 	u32 ucr1, ucr2, ucr4, uts;
@@ -485,7 +484,7 @@ static void imx_uart_stop_rx(struct uart_port *port)
 	/* See SER_RS485_ENABLED/UTS_LOOP comment in imx_uart_probe() */
 	if (port->rs485.flags & SER_RS485_ENABLED &&
 	    port->rs485.flags & SER_RS485_RTS_ON_SEND &&
-	    sport->have_rtscts && !sport->have_rtsgpio) {
+	    sport->have_rtscts && !sport->have_rtsgpio && loopback) {
 		uts = imx_uart_readl(sport, imx_uart_uts_reg(sport));
 		uts |= UTS_LOOP;
 		imx_uart_writel(sport, uts, imx_uart_uts_reg(sport));
@@ -497,6 +496,16 @@ static void imx_uart_stop_rx(struct uart_port *port)
 	imx_uart_writel(sport, ucr2, UCR2);
 }
 
+/* called with port.lock taken and irqs off */
+static void imx_uart_stop_rx(struct uart_port *port)
+{
+	/*
+	 * Stop RX and enable loopback in order to make sure RS485 bus
+	 * is not blocked. Se comment in imx_uart_probe().
+	 */
+	imx_uart_stop_rx_with_loopback_ctrl(port, true);
+}
+
 /* called with port.lock taken and irqs off */
 static void imx_uart_enable_ms(struct uart_port *port)
 {
@@ -682,9 +691,14 @@ static void imx_uart_start_tx(struct uart_port *port)
 				imx_uart_rts_inactive(sport, &ucr2);
 			imx_uart_writel(sport, ucr2, UCR2);
 
+			/*
+			 * Since we are about to transmit we can not stop RX
+			 * with loopback enabled because that will make our
+			 * transmitted data being just looped to RX.
+			 */
 			if (!(port->rs485.flags & SER_RS485_RX_DURING_TX) &&
 			    !port->rs485_rx_during_tx_gpio)
-				imx_uart_stop_rx(port);
+				imx_uart_stop_rx_with_loopback_ctrl(port, false);
 
 			sport->tx_state = WAIT_AFTER_RTS;
 

drivers/tty/serial/qcom_geni_serial.c

@@ -851,19 +851,21 @@ static void qcom_geni_serial_stop_tx(struct uart_port *uport)
 }
 
 static void qcom_geni_serial_send_chunk_fifo(struct uart_port *uport,
-					     unsigned int remaining)
+					     unsigned int chunk)
 {
 	struct qcom_geni_serial_port *port = to_dev_port(uport);
 	struct circ_buf *xmit = &uport->state->xmit;
-	unsigned int tx_bytes;
+	unsigned int tx_bytes, c, remaining = chunk;
 	u8 buf[BYTES_PER_FIFO_WORD];
 
 	while (remaining) {
 		memset(buf, 0, sizeof(buf));
 		tx_bytes = min(remaining, BYTES_PER_FIFO_WORD);
 
-		memcpy(buf, &xmit->buf[xmit->tail], tx_bytes);
-		uart_xmit_advance(uport, tx_bytes);
+		for (c = 0; c < tx_bytes ; c++) {
+			buf[c] = xmit->buf[xmit->tail];
+			uart_xmit_advance(uport, 1);
+		}
 
 		iowrite32_rep(uport->membase + SE_GENI_TX_FIFOn, buf, 1);
 

drivers/tty/serial/serial_port.c

@@ -46,8 +46,31 @@ static int serial_port_runtime_resume(struct device *dev)
 	return 0;
 }
 
+static int serial_port_runtime_suspend(struct device *dev)
+{
+	struct serial_port_device *port_dev = to_serial_base_port_device(dev);
+	struct uart_port *port = port_dev->port;
+	unsigned long flags;
+	bool busy;
+
+	if (port->flags & UPF_DEAD)
+		return 0;
+
+	uart_port_lock_irqsave(port, &flags);
+	busy = __serial_port_busy(port);
+	if (busy)
+		port->ops->start_tx(port);
+	uart_port_unlock_irqrestore(port, flags);
+
+	if (busy)
+		pm_runtime_mark_last_busy(dev);
+
+	return busy ? -EBUSY : 0;
+}
+
 static DEFINE_RUNTIME_DEV_PM_OPS(serial_port_pm,
-				 NULL, serial_port_runtime_resume, NULL);
+				 serial_port_runtime_suspend,
+				 serial_port_runtime_resume, NULL);
 
 static int serial_port_probe(struct device *dev)
 {

drivers/tty/vt/vt.c

@@ -381,7 +381,7 @@ static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
 		u32 *ln = vc->vc_uni_lines[vc->state.y];
 		unsigned int x = vc->state.x, cols = vc->vc_cols;
 
-		memcpy(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
+		memmove(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
 		memset32(&ln[cols - nr], ' ', nr);
 	}
 }