TTY/Serial driver patches for 4.21-rc1

Here is the large TTY/Serial driver set of patches for 4.21-rc1.
 
 A number of small serial driver changes along with some good tty core
 fixes for long-reported issues with locking.  There is also a new
 console font added to the tree, for high-res screens, so that should be
 helpful for many.
 
 The last patch in the series is a revert of an older one in the tree, it
 came late but it resolves a reported issue that linux-next was having
 for some people.
 
 Full details are in the shortlog, and all of these, with the exception
 of the revert, have been in linux-next for a while with no reported
 issues.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here is the large TTY/Serial driver set of patches for 4.21-rc1.

  A number of small serial driver changes along with some good tty core
  fixes for long-reported issues with locking. There is also a new
  console font added to the tree, for high-res screens, so that should
  be helpful for many.

  The last patch in the series is a revert of an older one in the tree,
  it came late but it resolves a reported issue that linux-next was
  having for some people.

  Full details are in the shortlog, and all of these, with the exception
  of the revert, have been in linux-next for a while with no reported
  issues"

* tag 'tty-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (85 commits)
  Revert "serial: 8250: Default SERIAL_OF_PLATFORM to SERIAL_8250"
  serial: sccnxp: Allow to use non-standard baud rates
  serial: sccnxp: Adds a delay between sequential read/write cycles
  tty: serial: qcom_geni_serial: Fix UART hang
  tty: serial: qcom_geni_serial: Fix wrap around of TX buffer
  serial: max310x: Fix tx_empty() callback
  dt-bindings: serial: sh-sci: Document r8a774c0 bindings
  dt-bindings: serial: sh-sci: Document r8a774a1 bindings
  Fonts: New Terminus large console font
  dt-bindings: serial: lpuart: add imx8qxp compatible string
  serial: uartps: Fix interrupt mask issue to handle the RX interrupts properly
  serial: uartps: Fix error path when alloc failed
  serial: uartps: Check if the device is a console
  serial: uartps: Add the device_init_wakeup
  tty: serial: samsung: Increase maximum baudrate
  tty: serial: samsung: Properly set flags in autoCTS mode
  tty: Use of_node_name_{eq,prefix} for node name comparisons
  tty/serial: do not free trasnmit buffer page under port lock
  serial: 8250: Rate limit serial port rx interrupts during input overruns
  dt-bindings: serial: 8250: Add rate limit for serial port input overruns
  ...

include/linux/font.h

@@ -32,6 +32,7 @@ struct font_desc {
 #define ACORN8x8_IDX	8
 #define	MINI4x6_IDX	9
 #define FONT6x10_IDX	10
+#define TER16x32_IDX	11
 
 extern const struct font_desc	font_vga_8x8,
 			font_vga_8x16,
@@ -43,7 +44,8 @@ extern const struct font_desc	font_vga_8x8,
 			font_sun_12x22,
 			font_acorn_8x8,
 			font_mini_4x6,
-			font_6x10;
+			font_6x10,
+			font_ter_16x32;
 
 /* Find a font with a specific name */
 

include/linux/lantiq.h

@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __LINUX_LANTIQ_H
+#define __LINUX_LANTIQ_H
+
+#ifdef CONFIG_LANTIQ
+#include <lantiq_soc.h>
+#else
+
+#ifndef LTQ_EARLY_ASC
+#define LTQ_EARLY_ASC 0
+#endif
+
+#ifndef CPHYSADDR
+#define CPHYSADDR(a) 0
+#endif
+
+static inline struct clk *clk_get_fpi(void)
+{
+	return NULL;
+}
+#endif /* CONFIG_LANTIQ */
+#endif /* __LINUX_LANTIQ_H */

include/linux/serdev.h

@@ -210,7 +210,7 @@ void serdev_device_wait_until_sent(struct serdev_device *, long);
 int serdev_device_get_tiocm(struct serdev_device *);
 int serdev_device_set_tiocm(struct serdev_device *, int, int);
 void serdev_device_write_wakeup(struct serdev_device *);
-int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, unsigned long);
+int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, long);
 void serdev_device_write_flush(struct serdev_device *);
 int serdev_device_write_room(struct serdev_device *);
 

include/linux/serial_8250.h

@@ -134,6 +134,10 @@ struct uart_8250_port {
 	void			(*dl_write)(struct uart_8250_port *, int);
 
 	struct uart_8250_em485 *em485;
+
+	/* Serial port overrun backoff */
+	struct delayed_work overrun_backoff;
+	u32 overrun_backoff_time_ms;
 };
 
 static inline struct uart_8250_port *up_to_u8250p(struct uart_port *up)

include/linux/serial_core.h

@@ -22,6 +22,7 @@
 
 #include <linux/bitops.h>
 #include <linux/compiler.h>
+#include <linux/console.h>
 #include <linux/interrupt.h>
 #include <linux/circ_buf.h>
 #include <linux/spinlock.h>
@@ -175,6 +176,7 @@ struct uart_port {
 	struct console		*cons;			/* struct console, if any */
 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
 	unsigned long		sysrq;			/* sysrq timeout */
+	unsigned int		sysrq_ch;		/* char for sysrq */
 #endif
 
 	/* flags must be updated while holding port mutex */
@@ -485,8 +487,42 @@ 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)
+{
+	if (port->sysrq) {
+		if (ch && time_before(jiffies, port->sysrq)) {
+			port->sysrq_ch = ch;
+			port->sysrq = 0;
+			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;
+
+	sysrq_ch = port->sysrq_ch;
+	port->sysrq_ch = 0;
+
+	spin_unlock_irqrestore(&port->lock, irqflags);
+
+	if (sysrq_ch)
+		handle_sysrq(sysrq_ch);
+}
 #else
-#define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; })
+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
 
 /*

include/linux/tty.h

@@ -366,6 +366,7 @@ struct tty_file_private {
 #define TTY_NO_WRITE_SPLIT 	17	/* Preserve write boundaries to driver */
 #define TTY_HUPPED 		18	/* Post driver->hangup() */
 #define TTY_HUPPING		19	/* Hangup in progress */
+#define TTY_LDISC_CHANGING	20	/* Change pending - non-block IO */
 #define TTY_LDISC_HALTED	22	/* Line discipline is halted */
 
 /* Values for tty->flow_change */
@@ -383,6 +384,12 @@ static inline void tty_set_flow_change(struct tty_struct *tty, int val)
 	smp_mb();
 }
 
+static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file)
+{
+	return file->f_flags & O_NONBLOCK ||
+		test_bit(TTY_LDISC_CHANGING, &tty->flags);
+}
+
 static inline bool tty_io_error(struct tty_struct *tty)
 {
 	return test_bit(TTY_IO_ERROR, &tty->flags);