kernel: Backport ar933x_uart build fix (fixes FS#2152)

Andrey has reported on OpenWrt's bug tracking system[1], that he
currently can't use ar93xx_uart as pure serial UART without console
(CONFIG_SERIAL_8250_CONSOLE and CONFIG_SERIAL_AR933X_CONSOLE undefined),
because compilation ends with following error:

 ar933x_uart.c: In function 'ar933x_uart_console_write':
 ar933x_uart.c:550:14: error: 'struct uart_port' has no
                               member named 'sysrq'

1. https://bugs.openwrt.org/index.php?do=details&task_id=2152

Signed-off-by: Petr Štetiar <ynezz@true.cz>

1 files changed, 99 insertions, 0 deletions

diff --git a/target/linux/generic/backport-4.19/060-v5.1-serial-ar933x_uart-Fix-build-failure-with-disabled-c.patch b/target/linux/generic/backport-4.19/060-v5.1-serial-ar933x_uart-Fix-build-failure-with-disabled-c.patch
new file mode 100644
index 0000000000..cb653170ef
--- /dev/null
+++ b/target/linux/generic/backport-4.19/060-v5.1-serial-ar933x_uart-Fix-build-failure-with-disabled-c.patch
@@ -0,0 +1,99 @@
+From 72ff51d8dd262d1fef25baedc2ac35116435be47 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Petr=20=C5=A0tetiar?= <ynezz@true.cz>
+Date: Wed, 6 Mar 2019 17:54:03 +0100
+Subject: [PATCH] serial: ar933x_uart: Fix build failure with disabled console
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Andrey has reported on OpenWrt's bug tracking system[1], that he
+currently can't use ar93xx_uart as pure serial UART without console
+(CONFIG_SERIAL_8250_CONSOLE and CONFIG_SERIAL_AR933X_CONSOLE undefined),
+because compilation ends with following error:
+
+ ar933x_uart.c: In function 'ar933x_uart_console_write':
+ ar933x_uart.c:550:14: error: 'struct uart_port' has no
+                               member named 'sysrq'
+
+So this patch moves all the code related to console handling behind
+series of CONFIG_SERIAL_AR933X_CONSOLE ifdefs.
+
+1. https://bugs.openwrt.org/index.php?do=details&task_id=2152
+
+Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+Cc: Jiri Slaby <jslaby@suse.com>
+Cc: Andrey Batyiev <batyiev@gmail.com>
+Reported-by: Andrey Batyiev <batyiev@gmail.com>
+Tested-by: Andrey Batyiev <batyiev@gmail.com>
+Signed-off-by: Petr Štetiar <ynezz@true.cz>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/ar933x_uart.c | 24 ++++++++----------------
+ 1 file changed, 8 insertions(+), 16 deletions(-)
+
+diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
+index db5df3d..3bdd56a 100644
+--- a/drivers/tty/serial/ar933x_uart.c
++++ b/drivers/tty/serial/ar933x_uart.c
+@@ -49,11 +49,6 @@ struct ar933x_uart_port {
+ 	struct clk		*clk;
+ };
+ 
+-static inline bool ar933x_uart_console_enabled(void)
+-{
+-	return IS_ENABLED(CONFIG_SERIAL_AR933X_CONSOLE);
+-}
+-
+ static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
+ 					    int offset)
+ {
+@@ -508,6 +503,7 @@ static int ar933x_uart_verify_port(struct uart_port *port,
+ 	.verify_port	= ar933x_uart_verify_port,
+ };
+ 
++#ifdef CONFIG_SERIAL_AR933X_CONSOLE
+ static struct ar933x_uart_port *
+ ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
+ 
+@@ -604,14 +600,7 @@ static int ar933x_uart_console_setup(struct console *co, char *options)
+ 	.index		= -1,
+ 	.data		= &ar933x_uart_driver,
+ };
+-
+-static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
+-{
+-	if (!ar933x_uart_console_enabled())
+-		return;
+-
+-	ar933x_console_ports[up->port.line] = up;
+-}
++#endif /* CONFIG_SERIAL_AR933X_CONSOLE */
+ 
+ static struct uart_driver ar933x_uart_driver = {
+ 	.owner		= THIS_MODULE,
+@@ -700,7 +689,9 @@ static int ar933x_uart_probe(struct platform_device *pdev)
+ 	baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
+ 	up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
+ 
+-	ar933x_uart_add_console_port(up);
++#ifdef CONFIG_SERIAL_AR933X_CONSOLE
++	ar933x_console_ports[up->port.line] = up;
++#endif
+ 
+ 	ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
+ 	if (ret)
+@@ -749,8 +740,9 @@ static int __init ar933x_uart_init(void)
+ {
+ 	int ret;
+ 
+-	if (ar933x_uart_console_enabled())
+-		ar933x_uart_driver.cons = &ar933x_uart_console;
++#ifdef CONFIG_SERIAL_AR933X_CONSOLE
++	ar933x_uart_driver.cons = &ar933x_uart_console;
++#endif
+ 
+ 	ret = uart_register_driver(&ar933x_uart_driver);
+ 	if (ret)
+-- 
+1.9.1
+