Merge tag 'tty-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty into master

Pull tty/serial driver fixes from Greg KH:
 :Here are some small tty and serial driver fixes for 5.8-rc6.

  The largest set of patches in here is a revert of the sysrq changes
  that went into 5.8-rc1 but turned out to cause a noticable overhead
  and cpu usage.

  Other than that, there's a few small serial driver fixes to resolve
  reported issues, and finally resolving the spinlock init problem on
  many serial driver consoles.

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

* tag 'tty-5.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  serial: core: Initialise spin lock before use in uart_configure_port()
  serial: mxs-auart: add missed iounmap() in probe failure and remove
  serial: sh-sci: Initialize spinlock for uart console
  Revert "tty: xilinx_uartps: Fix missing id assignment to the console"
  serial: core: drop redundant sysrq checks
  serial: core: fix sysrq overhead regression
  Revert "serial: core: Refactor uart_unlock_and_check_sysrq()"
  tty/serial: fix serial_core.c kernel-doc warnings
  tty: serial: cpm_uart: Fix behaviour for non existing GPIOs

Author: torvalds

drivers/tty/serial/cpm_uart/cpm_uart_core.c

@@ -1215,7 +1215,12 @@ static int cpm_uart_init_port(struct device_node *np,
 
 		pinfo->gpios[i] = NULL;
 
-		gpiod = devm_gpiod_get_index(dev, NULL, i, GPIOD_ASIS);
+		gpiod = devm_gpiod_get_index_optional(dev, NULL, i, GPIOD_ASIS);
+
+		if (IS_ERR(gpiod)) {
+			ret = PTR_ERR(gpiod);
+			goto out_irq;
+		}
 
 		if (gpiod) {
 			if (i == GPIO_RTS || i == GPIO_DTR)
@@ -1237,6 +1242,8 @@ static int cpm_uart_init_port(struct device_node *np,
 
 	return cpm_uart_request_port(&pinfo->port);
 
+out_irq:
+	irq_dispose_mapping(pinfo->port.irq);
 out_pram:
 	cpm_uart_unmap_pram(pinfo, pram);
 out_mem:

drivers/tty/serial/mxs-auart.c

@@ -1698,29 +1698,29 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		ret = irq;
-		goto out_disable_clks;
+		goto out_iounmap;
 	}
 
 	s->port.irq = irq;
 	ret = devm_request_irq(&pdev->dev, irq, mxs_auart_irq_handle, 0,
 			       dev_name(&pdev->dev), s);
 	if (ret)
-		goto out_disable_clks;
+		goto out_iounmap;
 
 	platform_set_drvdata(pdev, s);
 
 	ret = mxs_auart_init_gpios(s, &pdev->dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to initialize GPIOs.\n");
-		goto out_disable_clks;
+		goto out_iounmap;
 	}
 
 	/*
 	 * Get the GPIO lines IRQ
 	 */
 	ret = mxs_auart_request_gpio_irq(s);
 	if (ret)
-		goto out_disable_clks;
+		goto out_iounmap;
 
 	auart_port[s->port.line] = s;
 
@@ -1746,6 +1746,9 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	mxs_auart_free_gpio_irq(s);
 	auart_port[pdev->id] = NULL;
 
+out_iounmap:
+	iounmap(s->port.membase);
+
 out_disable_clks:
 	if (is_asm9260_auart(s)) {
 		clk_disable_unprepare(s->clk);
@@ -1761,6 +1764,7 @@ static int mxs_auart_remove(struct platform_device *pdev)
 	uart_remove_one_port(&auart_driver, &s->port);
 	auart_port[pdev->id] = NULL;
 	mxs_auart_free_gpio_irq(s);
+	iounmap(s->port.membase);
 	if (is_asm9260_auart(s)) {
 		clk_disable_unprepare(s->clk);
 		clk_disable_unprepare(s->clk_ahb);

drivers/tty/serial/serial_core.c

@@ -41,8 +41,6 @@ static struct lock_class_key port_lock_key;
 
 #define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)
 
-#define SYSRQ_TIMEOUT	(HZ * 5)
-
 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
 					struct ktermios *old_termios);
 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
@@ -1916,6 +1914,12 @@ static inline bool uart_console_enabled(struct uart_port *port)
 	return uart_console(port) && (port->cons->flags & CON_ENABLED);
 }
 
+static void __uart_port_spin_lock_init(struct uart_port *port)
+{
+	spin_lock_init(&port->lock);
+	lockdep_set_class(&port->lock, &port_lock_key);
+}
+
 /*
  * Ensure that the serial console lock is initialised early.
  * If this port is a console, then the spinlock is already initialised.
@@ -1925,8 +1929,7 @@ static inline void uart_port_spin_lock_init(struct uart_port *port)
 	if (uart_console(port))
 		return;
 
-	spin_lock_init(&port->lock);
-	lockdep_set_class(&port->lock, &port_lock_key);
+	__uart_port_spin_lock_init(port);
 }
 
 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
@@ -2372,6 +2375,13 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state,
 		/* Power up port for set_mctrl() */
 		uart_change_pm(state, UART_PM_STATE_ON);
 
+		/*
+		 * If this driver supports console, and it hasn't been
+		 * successfully registered yet, initialise spin lock for it.
+		 */
+		if (port->cons && !(port->cons->flags & CON_ENABLED))
+			__uart_port_spin_lock_init(port);
+
 		/*
 		 * Ensure that the modem control lines are de-activated.
 		 * keep the DTR setting that is set in uart_set_options()
@@ -3163,7 +3173,7 @@ static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
  *	Returns false if @ch is out of enabling sequence and should be
  *	handled some other way, true if @ch was consumed.
  */
-static bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
+bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
 {
 	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
 
@@ -3186,99 +3196,9 @@ static bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
 	port->sysrq = 0;
 	return true;
 }
-#else
-static inline bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
-{
-	return false;
-}
+EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
 #endif
 
-int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
-{
-	if (!IS_ENABLED(CONFIG_MAGIC_SYSRQ_SERIAL))
-		return 0;
-
-	if (!port->has_sysrq || !port->sysrq)
-		return 0;
-
-	if (ch && time_before(jiffies, port->sysrq)) {
-		if (sysrq_mask()) {
-			handle_sysrq(ch);
-			port->sysrq = 0;
-			return 1;
-		}
-		if (uart_try_toggle_sysrq(port, ch))
-			return 1;
-	}
-	port->sysrq = 0;
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(uart_handle_sysrq_char);
-
-int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
-{
-	if (!IS_ENABLED(CONFIG_MAGIC_SYSRQ_SERIAL))
-		return 0;
-
-	if (!port->has_sysrq || !port->sysrq)
-		return 0;
-
-	if (ch && time_before(jiffies, port->sysrq)) {
-		if (sysrq_mask()) {
-			port->sysrq_ch = ch;
-			port->sysrq = 0;
-			return 1;
-		}
-		if (uart_try_toggle_sysrq(port, ch))
-			return 1;
-	}
-	port->sysrq = 0;
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(uart_prepare_sysrq_char);
-
-void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long flags)
-__releases(&port->lock)
-{
-	if (port->has_sysrq) {
-		int sysrq_ch = port->sysrq_ch;
-
-		port->sysrq_ch = 0;
-		spin_unlock_irqrestore(&port->lock, flags);
-		if (sysrq_ch)
-			handle_sysrq(sysrq_ch);
-	} else {
-		spin_unlock_irqrestore(&port->lock, flags);
-	}
-}
-EXPORT_SYMBOL_GPL(uart_unlock_and_check_sysrq);
-
-/*
- * We do the SysRQ and SAK checking like this...
- */
-int uart_handle_break(struct uart_port *port)
-{
-	struct uart_state *state = port->state;
-
-	if (port->handle_break)
-		port->handle_break(port);
-
-	if (port->has_sysrq && uart_console(port)) {
-		if (!port->sysrq) {
-			port->sysrq = jiffies + SYSRQ_TIMEOUT;
-			return 1;
-		}
-		port->sysrq = 0;
-	}
-
-	if (port->flags & UPF_SAK)
-		do_SAK(state->port.tty);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(uart_handle_break);
-
 EXPORT_SYMBOL(uart_write_wakeup);
 EXPORT_SYMBOL(uart_register_driver);
 EXPORT_SYMBOL(uart_unregister_driver);
@@ -3289,8 +3209,7 @@ EXPORT_SYMBOL(uart_remove_one_port);
 
 /**
  * uart_get_rs485_mode() - retrieve rs485 properties for given uart
- * @dev: uart device
- * @rs485conf: output parameter
+ * @port: uart device's target port
  *
  * This function implements the device tree binding described in
  * Documentation/devicetree/bindings/serial/rs485.txt.

drivers/tty/serial/sh-sci.c

@@ -3301,6 +3301,9 @@ static int sci_probe_single(struct platform_device *dev,
 		sciport->port.flags |= UPF_HARD_FLOW;
 	}
 
+	if (sci_uart_driver.cons->index == sciport->port.line)
+		spin_lock_init(&sciport->port.lock);
+
 	ret = uart_add_one_port(&sci_uart_driver, &sciport->port);
 	if (ret) {
 		sci_cleanup_single(sciport);

drivers/tty/serial/xilinx_uartps.c

@@ -1465,7 +1465,6 @@ static int cdns_uart_probe(struct platform_device *pdev)
 		cdns_uart_uart_driver.nr = CDNS_UART_NR_PORTS;
 #ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
 		cdns_uart_uart_driver.cons = &cdns_uart_console;
-		cdns_uart_console.index = id;
 #endif
 
 		rc = uart_register_driver(&cdns_uart_uart_driver);

include/linux/serial_core.h

@@ -462,10 +462,104 @@ extern void uart_handle_cts_change(struct uart_port *uport,
 extern void uart_insert_char(struct uart_port *port, unsigned int status,
 		 unsigned int overrun, unsigned int ch, unsigned int flag);
 
-extern int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch);
-extern int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch);
-extern void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long flags);
-extern int uart_handle_break(struct uart_port *port);
+#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
+#define SYSRQ_TIMEOUT	(HZ * 5)
+
+bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
+
+static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
+{
+	if (!port->sysrq)
+		return 0;
+
+	if (ch && time_before(jiffies, port->sysrq)) {
+		if (sysrq_mask()) {
+			handle_sysrq(ch);
+			port->sysrq = 0;
+			return 1;
+		}
+		if (uart_try_toggle_sysrq(port, ch))
+			return 1;
+	}
+	port->sysrq = 0;
+
+	return 0;
+}
+
+static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
+{
+	if (!port->sysrq)
+		return 0;
+
+	if (ch && time_before(jiffies, port->sysrq)) {
+		if (sysrq_mask()) {
+			port->sysrq_ch = ch;
+			port->sysrq = 0;
+			return 1;
+		}
+		if (uart_try_toggle_sysrq(port, ch))
+			return 1;
+	}
+	port->sysrq = 0;
+
+	return 0;
+}
+
+static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
+{
+	int sysrq_ch;
+
+	if (!port->has_sysrq) {
+		spin_unlock_irqrestore(&port->lock, irqflags);
+		return;
+	}
+
+	sysrq_ch = port->sysrq_ch;
+	port->sysrq_ch = 0;
+
+	spin_unlock_irqrestore(&port->lock, irqflags);
+
+	if (sysrq_ch)
+		handle_sysrq(sysrq_ch);
+}
+#else	/* CONFIG_MAGIC_SYSRQ_SERIAL */
+static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
+{
+	return 0;
+}
+static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
+{
+	return 0;
+}
+static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
+{
+	spin_unlock_irqrestore(&port->lock, irqflags);
+}
+#endif	/* CONFIG_MAGIC_SYSRQ_SERIAL */
+
+/*
+ * We do the SysRQ and SAK checking like this...
+ */
+static inline int uart_handle_break(struct uart_port *port)
+{
+	struct uart_state *state = port->state;
+
+	if (port->handle_break)
+		port->handle_break(port);
+
+#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
+	if (port->has_sysrq && uart_console(port)) {
+		if (!port->sysrq) {
+			port->sysrq = jiffies + SYSRQ_TIMEOUT;
+			return 1;
+		}
+		port->sysrq = 0;
+	}
+#endif
+	if (port->flags & UPF_SAK)
+		do_SAK(state->port.tty);
+	return 0;
+}
 
 /*
  *	UART_ENABLE_MS - determine if port should enable modem status irqs