Merge tag 'tty-5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty fixes from Greg KH:
 "Here are some small tty/serial fixes for 5.10-rc5 that resolve some
  reported issues:

   - speakup crash when telling the kernel to use a device that isn't
     really there

   - imx serial driver fixes for reported problems

   - ar933x_uart driver fix for probe error handling path

  All have been in linux-next for a while with no reported issues"

* tag 'tty-5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: ar933x_uart: disable clk on error handling path in probe
  tty: serial: imx: keep console clocks always on
  speakup: Do not let the line discipline be used several times
  tty: serial: imx: fix potential deadlock

Author: torvalds

drivers/accessibility/speakup/spk_ttyio.c

@@ -49,15 +49,25 @@ static int spk_ttyio_ldisc_open(struct tty_struct *tty)
 
 	if (!tty->ops->write)
 		return -EOPNOTSUPP;
+
+	mutex_lock(&speakup_tty_mutex);
+	if (speakup_tty) {
+		mutex_unlock(&speakup_tty_mutex);
+		return -EBUSY;
+	}
 	speakup_tty = tty;
 
 	ldisc_data = kmalloc(sizeof(*ldisc_data), GFP_KERNEL);
-	if (!ldisc_data)
+	if (!ldisc_data) {
+		speakup_tty = NULL;
+		mutex_unlock(&speakup_tty_mutex);
 		return -ENOMEM;
+	}
 
 	init_completion(&ldisc_data->completion);
 	ldisc_data->buf_free = true;
 	speakup_tty->disc_data = ldisc_data;
+	mutex_unlock(&speakup_tty_mutex);
 
 	return 0;
 }

drivers/tty/serial/ar933x_uart.c

@@ -789,8 +789,10 @@ static int ar933x_uart_probe(struct platform_device *pdev)
 		goto err_disable_clk;
 
 	up->gpios = mctrl_gpio_init(port, 0);
-	if (IS_ERR(up->gpios) && PTR_ERR(up->gpios) != -ENOSYS)
-		return PTR_ERR(up->gpios);
+	if (IS_ERR(up->gpios) && PTR_ERR(up->gpios) != -ENOSYS) {
+		ret = PTR_ERR(up->gpios);
+		goto err_disable_clk;
+	}
 
 	up->rts_gpiod = mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS);
 

drivers/tty/serial/imx.c

@@ -942,8 +942,14 @@ static irqreturn_t imx_uart_int(int irq, void *dev_id)
 	struct imx_port *sport = dev_id;
 	unsigned int usr1, usr2, ucr1, ucr2, ucr3, ucr4;
 	irqreturn_t ret = IRQ_NONE;
+	unsigned long flags = 0;
 
-	spin_lock(&sport->port.lock);
+	/*
+	 * IRQs might not be disabled upon entering this interrupt handler,
+	 * e.g. when interrupt handlers are forced to be threaded. To support
+	 * this scenario as well, disable IRQs when acquiring the spinlock.
+	 */
+	spin_lock_irqsave(&sport->port.lock, flags);
 
 	usr1 = imx_uart_readl(sport, USR1);
 	usr2 = imx_uart_readl(sport, USR2);
@@ -1013,7 +1019,7 @@ static irqreturn_t imx_uart_int(int irq, void *dev_id)
 		ret = IRQ_HANDLED;
 	}
 
-	spin_unlock(&sport->port.lock);
+	spin_unlock_irqrestore(&sport->port.lock, flags);
 
 	return ret;
 }
@@ -2002,16 +2008,6 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
 	unsigned int ucr1;
 	unsigned long flags = 0;
 	int locked = 1;
-	int retval;
-
-	retval = clk_enable(sport->clk_per);
-	if (retval)
-		return;
-	retval = clk_enable(sport->clk_ipg);
-	if (retval) {
-		clk_disable(sport->clk_per);
-		return;
-	}
 
 	if (sport->port.sysrq)
 		locked = 0;
@@ -2047,9 +2043,6 @@ imx_uart_console_write(struct console *co, const char *s, unsigned int count)
 
 	if (locked)
 		spin_unlock_irqrestore(&sport->port.lock, flags);
-
-	clk_disable(sport->clk_ipg);
-	clk_disable(sport->clk_per);
 }
 
 /*
@@ -2150,15 +2143,14 @@ imx_uart_console_setup(struct console *co, char *options)
 
 	retval = uart_set_options(&sport->port, co, baud, parity, bits, flow);
 
-	clk_disable(sport->clk_ipg);
 	if (retval) {
-		clk_unprepare(sport->clk_ipg);
+		clk_disable_unprepare(sport->clk_ipg);
 		goto error_console;
 	}
 
-	retval = clk_prepare(sport->clk_per);
+	retval = clk_prepare_enable(sport->clk_per);
 	if (retval)
-		clk_unprepare(sport->clk_ipg);
+		clk_disable_unprepare(sport->clk_ipg);
 
 error_console:
 	return retval;