1 files changed, 96 insertions, 79 deletions

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index ff85ebd3a007..2c1a0254d3f4 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -156,7 +156,7 @@ static void __uart_start(struct uart_state *state)
 	 * enabled, serial_port_runtime_resume() calls start_tx() again
 	 * after enabling the device.
 	 */
-	if (pm_runtime_active(&port_dev->dev))
+	if (!pm_runtime_enabled(port->dev) || pm_runtime_active(&port_dev->dev))
 		port->ops->start_tx(port);
 	pm_runtime_mark_last_busy(&port_dev->dev);
 	pm_runtime_put_autosuspend(&port_dev->dev);
@@ -243,25 +243,12 @@ static void uart_change_line_settings(struct tty_struct *tty, struct uart_state
 	uart_port_unlock_irq(uport);
 }
 
-/*
- * Startup the port.  This will be called once per open.  All calls
- * will be serialised by the per-port mutex.
- */
-static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
-			     bool init_hw)
+static int uart_alloc_xmit_buf(struct tty_port *port)
 {
-	struct uart_port *uport = uart_port_check(state);
+	struct uart_state *state = container_of(port, struct uart_state, port);
+	struct uart_port *uport;
 	unsigned long flags;
 	unsigned long page;
-	int retval = 0;
-
-	if (uport->type == PORT_UNKNOWN)
-		return 1;
-
-	/*
-	 * Make sure the device is in D0 state.
-	 */
-	uart_change_pm(state, UART_PM_STATE_ON);
 
 	/*
 	 * Initialise and allocate the transmit and temporary
@@ -271,20 +258,68 @@ static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
 	if (!page)
 		return -ENOMEM;
 
-	uart_port_lock(state, flags);
-	if (!state->xmit.buf) {
-		state->xmit.buf = (unsigned char *) page;
-		uart_circ_clear(&state->xmit);
+	uport = uart_port_lock(state, flags);
+	if (!state->port.xmit_buf) {
+		state->port.xmit_buf = (unsigned char *)page;
+		kfifo_init(&state->port.xmit_fifo, state->port.xmit_buf,
+				PAGE_SIZE);
 		uart_port_unlock(uport, flags);
 	} else {
 		uart_port_unlock(uport, flags);
 		/*
 		 * Do not free() the page under the port lock, see
-		 * uart_shutdown().
+		 * uart_free_xmit_buf().
 		 */
 		free_page(page);
 	}
 
+	return 0;
+}
+
+static void uart_free_xmit_buf(struct tty_port *port)
+{
+	struct uart_state *state = container_of(port, struct uart_state, port);
+	struct uart_port *uport;
+	unsigned long flags;
+	char *xmit_buf;
+
+	/*
+	 * Do not free() the transmit buffer page under the port lock since
+	 * this can create various circular locking scenarios. For instance,
+	 * console driver may need to allocate/free a debug object, which
+	 * can end up in printk() recursion.
+	 */
+	uport = uart_port_lock(state, flags);
+	xmit_buf = port->xmit_buf;
+	port->xmit_buf = NULL;
+	INIT_KFIFO(port->xmit_fifo);
+	uart_port_unlock(uport, flags);
+
+	free_page((unsigned long)xmit_buf);
+}
+
+/*
+ * Startup the port.  This will be called once per open.  All calls
+ * will be serialised by the per-port mutex.
+ */
+static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
+			     bool init_hw)
+{
+	struct uart_port *uport = uart_port_check(state);
+	int retval;
+
+	if (uport->type == PORT_UNKNOWN)
+		return 1;
+
+	/*
+	 * Make sure the device is in D0 state.
+	 */
+	uart_change_pm(state, UART_PM_STATE_ON);
+
+	retval = uart_alloc_xmit_buf(&state->port);
+	if (retval)
+		return retval;
+
 	retval = uport->ops->startup(uport);
 	if (retval == 0) {
 		if (uart_console(uport) && uport->cons->cflag) {
@@ -323,16 +358,26 @@ static int uart_startup(struct tty_struct *tty, struct uart_state *state,
 			bool init_hw)
 {
 	struct tty_port *port = &state->port;
+	struct uart_port *uport;
 	int retval;
 
 	if (tty_port_initialized(port))
-		return 0;
+		goto out_base_port_startup;
 
 	retval = uart_port_startup(tty, state, init_hw);
-	if (retval)
+	if (retval) {
 		set_bit(TTY_IO_ERROR, &tty->flags);
+		return retval;
+	}
 
-	return retval;
+out_base_port_startup:
+	uport = uart_port_check(state);
+	if (!uport)
+		return -EIO;
+
+	serial_base_port_startup(uport);
+
+	return 0;
 }
 
 /*
@@ -346,8 +391,6 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 {
 	struct uart_port *uport = uart_port_check(state);
 	struct tty_port *port = &state->port;
-	unsigned long flags;
-	char *xmit_buf = NULL;
 
 	/*
 	 * Set the TTY IO error marker
@@ -355,6 +398,9 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 	if (tty)
 		set_bit(TTY_IO_ERROR, &tty->flags);
 
+	if (uport)
+		serial_base_port_shutdown(uport);
+
 	if (tty_port_initialized(port)) {
 		tty_port_set_initialized(port, false);
 
@@ -380,18 +426,7 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
 	 */
 	tty_port_set_suspended(port, false);
 
-	/*
-	 * Do not free() the transmit buffer page under the port lock since
-	 * this can create various circular locking scenarios. For instance,
-	 * console driver may need to allocate/free a debug object, which
-	 * can endup in printk() recursion.
-	 */
-	uart_port_lock(state, flags);
-	xmit_buf = state->xmit.buf;
-	state->xmit.buf = NULL;
-	uart_port_unlock(uport, flags);
-
-	free_page((unsigned long)xmit_buf);
+	uart_free_xmit_buf(port);
 }
 
 /**
@@ -552,22 +587,17 @@ static int uart_put_char(struct tty_struct *tty, u8 c)
 {
 	struct uart_state *state = tty->driver_data;
 	struct uart_port *port;
-	struct circ_buf *circ;
 	unsigned long flags;
 	int ret = 0;
 
-	circ = &state->xmit;
 	port = uart_port_lock(state, flags);
-	if (!circ->buf) {
+	if (!state->port.xmit_buf) {
 		uart_port_unlock(port, flags);
 		return 0;
 	}
 
-	if (port && uart_circ_chars_free(circ) != 0) {
-		circ->buf[circ->head] = c;
-		circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
-		ret = 1;
-	}
+	if (port)
+		ret = kfifo_put(&state->port.xmit_fifo, c);
 	uart_port_unlock(port, flags);
 	return ret;
 }
@@ -581,9 +611,8 @@ static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
 {
 	struct uart_state *state = tty->driver_data;
 	struct uart_port *port;
-	struct circ_buf *circ;
 	unsigned long flags;
-	int c, ret = 0;
+	int ret = 0;
 
 	/*
 	 * This means you called this function _after_ the port was
@@ -593,24 +622,13 @@ static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
 		return -EL3HLT;
 
 	port = uart_port_lock(state, flags);
-	circ = &state->xmit;
-	if (!circ->buf) {
+	if (WARN_ON_ONCE(!state->port.xmit_buf)) {
 		uart_port_unlock(port, flags);
 		return 0;
 	}
 
-	while (port) {
-		c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
-		if (count < c)
-			c = count;
-		if (c <= 0)
-			break;
-		memcpy(circ->buf + circ->head, buf, c);
-		circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
-		buf += c;
-		count -= c;
-		ret += c;
-	}
+	if (port)
+		ret = kfifo_in(&state->port.xmit_fifo, buf, count);
 
 	__uart_start(state);
 	uart_port_unlock(port, flags);
@@ -625,7 +643,7 @@ static unsigned int uart_write_room(struct tty_struct *tty)
 	unsigned int ret;
 
 	port = uart_port_lock(state, flags);
-	ret = uart_circ_chars_free(&state->xmit);
+	ret = kfifo_avail(&state->port.xmit_fifo);
 	uart_port_unlock(port, flags);
 	return ret;
 }
@@ -638,7 +656,7 @@ static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
 	unsigned int ret;
 
 	port = uart_port_lock(state, flags);
-	ret = uart_circ_chars_pending(&state->xmit);
+	ret = kfifo_len(&state->port.xmit_fifo);
 	uart_port_unlock(port, flags);
 	return ret;
 }
@@ -661,7 +679,7 @@ static void uart_flush_buffer(struct tty_struct *tty)
 	port = uart_port_lock(state, flags);
 	if (!port)
 		return;
-	uart_circ_clear(&state->xmit);
+	kfifo_reset(&state->port.xmit_fifo);
 	if (port->ops->flush_buffer)
 		port->ops->flush_buffer(port);
 	uart_port_unlock(port, flags);
@@ -1064,7 +1082,7 @@ static int uart_get_lsr_info(struct tty_struct *tty,
 	 * interrupt happens).
 	 */
 	if (uport->x_char ||
-	    ((uart_circ_chars_pending(&state->xmit) > 0) &&
+	    (!kfifo_is_empty(&state->port.xmit_fifo) &&
 	     !uart_tx_stopped(uport)))
 		result &= ~TIOCSER_TEMT;
 
@@ -1762,7 +1780,6 @@ static void uart_tty_port_shutdown(struct tty_port *port)
 {
 	struct uart_state *state = container_of(port, struct uart_state, port);
 	struct uart_port *uport = uart_port_check(state);
-	char *buf;
 
 	/*
 	 * At this point, we stop accepting input.  To do this, we
@@ -1775,6 +1792,7 @@ static void uart_tty_port_shutdown(struct tty_port *port)
 	uport->ops->stop_rx(uport);
 	uart_port_unlock_irq(uport);
 
+	serial_base_port_shutdown(uport);
 	uart_port_shutdown(port);
 
 	/*
@@ -1784,15 +1802,7 @@ static void uart_tty_port_shutdown(struct tty_port *port)
 	 */
 	tty_port_set_suspended(port, false);
 
-	/*
-	 * Free the transmit buffer.
-	 */
-	uart_port_lock_irq(uport);
-	buf = state->xmit.buf;
-	state->xmit.buf = NULL;
-	uart_port_unlock_irq(uport);
-
-	free_page((unsigned long)buf);
+	uart_free_xmit_buf(port);
 
 	uart_change_pm(state, UART_PM_STATE_OFF);
 }
@@ -2398,6 +2408,7 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
 			uport->ops->stop_rx(uport);
 			uart_port_unlock_irq(uport);
 		}
+		device_set_awake_path(uport->dev);
 		goto unlock;
 	}
 
@@ -3196,6 +3207,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
 	if (uport->attr_group)
 		uport->tty_groups[1] = uport->attr_group;
 
+	/* Ensure serdev drivers can call serdev_device_open() right away */
+	uport->flags &= ~UPF_DEAD;
+
 	/*
 	 * Register the port whether it's detected or not.  This allows
 	 * setserial to be used to alter this port's parameters.
@@ -3206,6 +3220,7 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
 	if (!IS_ERR(tty_dev)) {
 		device_set_wakeup_capable(tty_dev, 1);
 	} else {
+		uport->flags |= UPF_DEAD;
 		dev_err(uport->dev, "Cannot register tty device on line %d\n",
 		       uport->line);
 	}
@@ -3407,11 +3422,13 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
 	if (ret)
 		goto err_unregister_ctrl_dev;
 
-	ret = serial_core_add_one_port(drv, port);
+	ret = serial_base_add_preferred_console(drv, port);
 	if (ret)
 		goto err_unregister_port_dev;
 
-	port->flags &= ~UPF_DEAD;
+	ret = serial_core_add_one_port(drv, port);
+	if (ret)
+		goto err_unregister_port_dev;
 
 	mutex_unlock(&port_mutex);