Merge tag 'tty-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty / serial updates from Greg KH:
 "Here is the big set of tty/serial driver changes for 6.10-rc1.
  Included in here are:

   - Usual good set of api cleanups and evolution by Jiri Slaby to make
     the serial interfaces move out of the 1990's by using kfifos
     instead of hand-rolling their own logic.

   - 8250_exar driver updates

   - max3100 driver updates

   - sc16is7xx driver updates

   - exar driver updates

   - sh-sci driver updates

   - tty ldisc api addition to help refuse bindings

   - other smaller serial driver updates

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

* tag 'tty-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (113 commits)
  serial: Clear UPF_DEAD before calling tty_port_register_device_attr_serdev()
  serial: imx: Raise TX trigger level to 8
  serial: 8250_pnp: Simplify "line" related code
  serial: sh-sci: simplify locking when re-issuing RXDMA fails
  serial: sh-sci: let timeout timer only run when DMA is scheduled
  serial: sh-sci: describe locking requirements for invalidating RXDMA
  serial: sh-sci: protect invalidating RXDMA on shutdown
  tty: add the option to have a tty reject a new ldisc
  serial: core: Call device_set_awake_path() for console port
  dt-bindings: serial: brcm,bcm2835-aux-uart: convert to dtschema
  tty: serial: uartps: Add support for uartps controller reset
  arm64: zynqmp: Add resets property for UART nodes
  dt-bindings: serial: cdns,uart: Add optional reset property
  serial: 8250_pnp: Switch to DEFINE_SIMPLE_DEV_PM_OPS()
  serial: 8250_exar: Keep the includes sorted
  serial: 8250_exar: Make type of bit the same in exar_ee_*_bit()
  serial: 8250_exar: Use BIT() in exar_ee_read()
  serial: 8250_exar: Switch to use dev_err_probe()
  serial: 8250_exar: Return directly from switch-cases
  serial: 8250_exar: Decrease indentation level
  ...

4 files changed, 225 insertions, 29 deletions

diff --git a/kernel/printk/Makefile b/kernel/printk/Makefile
index 39a2b61c7232..040fe7d1eda2 100644
--- a/kernel/printk/Makefile
+++ b/kernel/printk/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-y	= printk.o
+obj-y	= printk.o conopt.o
 obj-$(CONFIG_PRINTK)	+= printk_safe.o nbcon.o
 obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)	+= braille.o
 obj-$(CONFIG_PRINTK_INDEX)	+= index.o
diff --git a/kernel/printk/conopt.c b/kernel/printk/conopt.c
new file mode 100644
index 000000000000..9d507bac3657
--- /dev/null
+++ b/kernel/printk/conopt.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Kernel command line console options for hardware based addressing
+ *
+ * Copyright (C) 2023 Texas Instruments Incorporated - https://www.ti.com/
+ * Author: Tony Lindgren <tony@atomide.com>
+ */
+
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include <asm/errno.h>
+
+#include "console_cmdline.h"
+
+/*
+ * Allow longer DEVNAME:0.0 style console naming such as abcd0000.serial:0.0
+ * in addition to the legacy ttyS0 style naming.
+ */
+#define CONSOLE_NAME_MAX	32
+
+#define CONSOLE_OPT_MAX		16
+#define CONSOLE_BRL_OPT_MAX	16
+
+struct console_option {
+	char name[CONSOLE_NAME_MAX];
+	char opt[CONSOLE_OPT_MAX];
+	char brl_opt[CONSOLE_BRL_OPT_MAX];
+	u8 has_brl_opt:1;
+};
+
+/* Updated only at console_setup() time, no locking needed */
+static struct console_option conopt[MAX_CMDLINECONSOLES];
+
+/**
+ * console_opt_save - Saves kernel command line console option for driver use
+ * @str: Kernel command line console name and option
+ * @brl_opt: Braille console options
+ *
+ * Saves a kernel command line console option for driver subsystems to use for
+ * adding a preferred console during init. Called from console_setup() only.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int __init console_opt_save(const char *str, const char *brl_opt)
+{
+	struct console_option *con;
+	size_t namelen, optlen;
+	const char *opt;
+	int i;
+
+	namelen = strcspn(str, ",");
+	if (namelen == 0 || namelen >= CONSOLE_NAME_MAX)
+		return -EINVAL;
+
+	opt = str + namelen;
+	if (*opt == ',')
+		opt++;
+
+	optlen = strlen(opt);
+	if (optlen >= CONSOLE_OPT_MAX)
+		return -EINVAL;
+
+	for (i = 0; i < MAX_CMDLINECONSOLES; i++) {
+		con = &conopt[i];
+
+		if (con->name[0]) {
+			if (!strncmp(str, con->name, namelen))
+				return 0;
+			continue;
+		}
+
+		/*
+		 * The name isn't terminated, only opt is. Empty opt is fine,
+		 * but brl_opt can be either empty or NULL. For more info, see
+		 * _braille_console_setup().
+		 */
+		strscpy(con->name, str, namelen + 1);
+		strscpy(con->opt, opt, CONSOLE_OPT_MAX);
+		if (brl_opt) {
+			strscpy(con->brl_opt, brl_opt, CONSOLE_BRL_OPT_MAX);
+			con->has_brl_opt = 1;
+		}
+
+		return 0;
+	}
+
+	return -ENOMEM;
+}
+
+static struct console_option *console_opt_find(const char *name)
+{
+	struct console_option *con;
+	int i;
+
+	for (i = 0; i < MAX_CMDLINECONSOLES; i++) {
+		con = &conopt[i];
+		if (!strcmp(name, con->name))
+			return con;
+	}
+
+	return NULL;
+}
+
+/**
+ * add_preferred_console_match - Adds a preferred console if a match is found
+ * @match: Expected console on kernel command line, such as console=DEVNAME:0.0
+ * @name: Name of the console character device to add such as ttyS
+ * @idx: Index for the console
+ *
+ * Allows driver subsystems to add a console after translating the command
+ * line name to the character device name used for the console. Options are
+ * added automatically based on the kernel command line. Duplicate preferred
+ * consoles are ignored by __add_preferred_console().
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int add_preferred_console_match(const char *match, const char *name,
+				const short idx)
+{
+	struct console_option *con;
+	char *brl_opt = NULL;
+
+	if (!match || !strlen(match) || !name || !strlen(name) ||
+	    idx < 0)
+		return -EINVAL;
+
+	con = console_opt_find(match);
+	if (!con)
+		return -ENOENT;
+
+	/*
+	 * See __add_preferred_console(). It checks for NULL brl_options to set
+	 * the preferred_console flag. Empty brl_opt instead of NULL leads into
+	 * the preferred_console flag not set, and CON_CONSDEV not being set,
+	 * and the boot console won't get disabled at the end of console_setup().
+	 */
+	if (con->has_brl_opt)
+		brl_opt = con->brl_opt;
+
+	console_opt_add_preferred_console(name, idx, con->opt, brl_opt);
+
+	return 0;
+}
diff --git a/kernel/printk/console_cmdline.h b/kernel/printk/console_cmdline.h
index 3ca74ad391d6..a125e0235589 100644
--- a/kernel/printk/console_cmdline.h
+++ b/kernel/printk/console_cmdline.h
@@ -2,6 +2,12 @@
 #ifndef _CONSOLE_CMDLINE_H
 #define _CONSOLE_CMDLINE_H
 
+#define MAX_CMDLINECONSOLES 8
+
+int console_opt_save(const char *str, const char *brl_opt);
+int console_opt_add_preferred_console(const char *name, const short idx,
+				      char *options, char *brl_options);
+
 struct console_cmdline
 {
 	char	name[16];			/* Name of the driver	    */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 3160d287d4cf..420fd310129d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -383,9 +383,6 @@ static int console_locked;
 /*
  *	Array of consoles built from command line options (console=)
  */
-
-#define MAX_CMDLINECONSOLES 8
-
 static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
 
 static int preferred_console = -1;
@@ -2503,6 +2500,17 @@ static int __init console_setup(char *str)
 	if (_braille_console_setup(&str, &brl_options))
 		return 1;
 
+	/* Save the console for driver subsystem use */
+	if (console_opt_save(str, brl_options))
+		return 1;
+
+	/* Flag register_console() to not call try_enable_default_console() */
+	console_set_on_cmdline = 1;
+
+	/* Don't attempt to parse a DEVNAME:0.0 style console */
+	if (strchr(str, ':'))
+		return 1;
+
 	/*
 	 * Decode str into name, index, options.
 	 */
@@ -2533,6 +2541,13 @@ static int __init console_setup(char *str)
 }
 __setup("console=", console_setup);
 
+/* Only called from add_preferred_console_match() */
+int console_opt_add_preferred_console(const char *name, const short idx,
+				      char *options, char *brl_options)
+{
+	return __add_preferred_console(name, idx, options, brl_options, true);
+}
+
 /**
  * add_preferred_console - add a device to the list of preferred consoles.
  * @name: device name
@@ -3146,6 +3161,40 @@ void console_unblank(void)
 		pr_flush(1000, true);
 }
 
+/*
+ * Rewind all consoles to the oldest available record.
+ *
+ * IMPORTANT: The function is safe only when called under
+ *            console_lock(). It is not enforced because
+ *            it is used as a best effort in panic().
+ */
+static void __console_rewind_all(void)
+{
+	struct console *c;
+	short flags;
+	int cookie;
+	u64 seq;
+
+	seq = prb_first_valid_seq(prb);
+
+	cookie = console_srcu_read_lock();
+	for_each_console_srcu(c) {
+		flags = console_srcu_read_flags(c);
+
+		if (flags & CON_NBCON) {
+			nbcon_seq_force(c, seq);
+		} else {
+			/*
+			 * This assignment is safe only when called under
+			 * console_lock(). On panic, legacy consoles are
+			 * only best effort.
+			 */
+			c->seq = seq;
+		}
+	}
+	console_srcu_read_unlock(cookie);
+}
+
 /**
  * console_flush_on_panic - flush console content on panic
  * @mode: flush all messages in buffer or just the pending ones
@@ -3174,30 +3223,8 @@ void console_flush_on_panic(enum con_flush_mode mode)
 	 */
 	console_may_schedule = 0;
 
-	if (mode == CONSOLE_REPLAY_ALL) {
-		struct console *c;
-		short flags;
-		int cookie;
-		u64 seq;
-
-		seq = prb_first_valid_seq(prb);
-
-		cookie = console_srcu_read_lock();
-		for_each_console_srcu(c) {
-			flags = console_srcu_read_flags(c);
-
-			if (flags & CON_NBCON) {
-				nbcon_seq_force(c, seq);
-			} else {
-				/*
-				 * This is an unsynchronized assignment. On
-				 * panic legacy consoles are only best effort.
-				 */
-				c->seq = seq;
-			}
-		}
-		console_srcu_read_unlock(cookie);
-	}
+	if (mode == CONSOLE_REPLAY_ALL)
+		__console_rewind_all();
 
 	console_flush_all(false, &next_seq, &handover);
 }
@@ -3495,7 +3522,7 @@ void register_console(struct console *newcon)
 	 * Note that a console with tty binding will have CON_CONSDEV
 	 * flag set and will be first in the list.
 	 */
-	if (preferred_console < 0) {
+	if (preferred_console < 0 && !console_set_on_cmdline) {
 		if (hlist_empty(&console_list) || !console_first()->device ||
 		    console_first()->flags & CON_BOOT) {
 			try_enable_default_console(newcon);
@@ -4286,6 +4313,23 @@ void kmsg_dump_rewind(struct kmsg_dump_iter *iter)
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
 
+/**
+ * console_replay_all - replay kernel log on consoles
+ *
+ * Try to obtain lock on console subsystem and replay all
+ * available records in printk buffer on the consoles.
+ * Does nothing if lock is not obtained.
+ *
+ * Context: Any context.
+ */
+void console_replay_all(void)
+{
+	if (console_trylock()) {
+		__console_rewind_all();
+		/* Consoles are flushed as part of console_unlock(). */
+		console_unlock();
+	}
+}
 #endif
 
 #ifdef CONFIG_SMP