pager: doc: Add mention of the pager feature

Add a note about the pager to the console documentation, with some more
information in the developer section. Also include the pager API.

Series-to: concept
Cover-letter:
Introduce a pager for the console
Some U-Boot commands can produce a lot of output and this can run off
top of the display. This series introduces a simple pager feature, to
allow the output to be read, before pressing SPACE to continue.

A fixed buffer size (4K) is used, which sets a limit on the permmited
output before paging fails and the output is simply written all in one
lot. In most cases this is plenty, but 'env print' does print the whole
environment as one string, so if the legacy distro-boot scripts are used
it could happen.

The default number of visible lines is set with a Kconfig option. Where
a video terminal is being used, the page size is set to match that. In
general U-Boot cannot guess the number of visible lines, since a serial
terminal may be in use.

There is also a 'pager' environment variable which can override any
detected value.

This initial series only counts newlines. It has no support for counting
characters so the result will be sub-optimal if very long lines are
written. This could be addressed in a future patch.

Some effort is made to handle common cases correctly. For example, if
stdout is changed to a serial or vidconsole device, that is used to
determine the page length. When redirecting sandbox to a file, no
attempt is made.

Future work may detect the terminal size by sending an ANSI sequence.
END

Signed-off-by: Simon Glass <sjg@chromium.org>
Series-version: 2

arch/sandbox/cpu/start.c

@@ -12,6 +12,7 @@
 #include <init.h>
 #include <log.h>
 #include <os.h>
+#include <pager.h>
 #include <sandbox_host.h>
 #include <sort.h>
 #include <spl.h>
@@ -136,6 +137,10 @@ int sandbox_main_loop_init(void)
 {
 	struct sandbox_state *state = state_get_current();
 
+	/* Apply pager bypass if requested */
+	if (state->pager_bypass)
+		pager_set_test_bypass(gd_pager(), true);
+
 	/* Execute command if required */
 	if (state->cmd || state->run_distro_boot) {
 		int retval = 0;
@@ -433,6 +438,15 @@ static int sandbox_cmdline_cb_autoboot_keyed(struct sandbox_state *state,
 }
 SANDBOX_CMDLINE_OPT(autoboot_keyed, 0, "Allow keyed autoboot");
 
+static int sandbox_cmdline_cb_no_term_present(struct sandbox_state *state,
+					      const char *arg)
+{
+	state->no_term_present = true;
+	return 0;
+}
+SANDBOX_CMDLINE_OPT_SHORT(no_term_present, 'A', 0,
+			  "Assume no terminal present (for pager testing)");
+
 static int sandbox_cmdline_cb_upl(struct sandbox_state *state, const char *arg)
 {
 	state->upl = true;
@@ -480,6 +494,16 @@ static int sandbox_cmdline_cb_soft_fail(struct sandbox_state *state,
 SANDBOX_CMDLINE_OPT_SHORT(soft_fail, 'f', 0,
 			  "continue test execution even after it fails");
 
+static int sandbox_cmdline_cb_pager_bypass(struct sandbox_state *state,
+					   const char *arg)
+{
+	state->pager_bypass = true;
+
+	return 0;
+}
+SANDBOX_CMDLINE_OPT_SHORT(pager_bypass, 'P', 0,
+			  "Enable pager bypass mode");
+
 static int sandbox_cmdline_cb_bind(struct sandbox_state *state, const char *arg)
 {
 	if (state->num_binds >= SB_MAX_BINDS) {

arch/sandbox/include/asm/state.h

@@ -175,6 +175,8 @@ struct sandbox_state {
 	bool native;			/* Adjust to reflect host arch */
 	bool no_flattree_tests;		/* Don't run second set of DM tests */
 	bool soft_fail;			/* Continue on failure */
+	bool pager_bypass;		/* Enable pager-bypass mode */
+	bool no_term_present;		/* Assume no terminal present */
 
 	/* Pointer to information for each SPI bus/cs */
 	struct sandbox_spi_info spi[CONFIG_SANDBOX_SPI_MAX_BUS]

cmd/bdinfo.c

@@ -14,6 +14,7 @@
 #include <lmb.h>
 #include <mapmem.h>
 #include <net.h>
+#include <pager.h>
 #include <serial.h>
 #include <video.h>
 #include <vsprintf.h>
@@ -132,6 +133,8 @@ static int bdinfo_print_all(struct bd_info *bd)
 	lprint_num_l("fdt_blob", (ulong)map_to_sysmem(gd->fdt_blob));
 	if (IS_ENABLED(CONFIG_VIDEO))
 		show_video_info();
+	if (IS_ENABLED(CONFIG_CONSOLE_PAGER))
+		printf("pager       = %d\n", gd_pager_page_len());
 #if CONFIG_IS_ENABLED(MULTI_DTB_FIT)
 	lprint_num_l("multi_dtb_fit", (ulong)gd->multi_dtb_fit);
 #endif

common/Kconfig

@@ -332,6 +332,28 @@ config SYS_DEVICE_NULLDEV
 	  operation of the console by setting stdout to "nulldev". Enable
 	  this to use a serial console under board control.
 
+config CONSOLE_PAGER
+	bool "Enable console output paging"
+	depends on CONSOLE_MUX
+	imply CMD_CONSOLE_EXTRA
+	imply SERIAL_TERM_PRESENT
+	default y if SANDBOX
+	help
+	  Enable pager functionality for console output. When enabled, long
+	  output will be paused after a configurable number of lines, waiting
+	  for user input (SPACE) to continue. The number of lines per page is
+	  controlled by the 'pager' environment variable. If the variable is
+	  not set or is empty, paging is disabled.
+
+config CONSOLE_PAGER_LINES
+	int "Number of lines per page"
+	depends on CONSOLE_PAGER
+	default 25
+	help
+	  Sets the default number of lines that the pager assumes is visible on
+	  the display. This is used as a default if the "pager" environment
+	  variable is unset.
+
 endmenu
 
 menu "Logging"

common/Makefile

@@ -26,6 +26,8 @@ obj-$(CONFIG_MII) += miiphyutil.o
 obj-$(CONFIG_CMD_MII) += miiphyutil.o
 obj-$(CONFIG_PHYLIB) += miiphyutil.o
 
+obj-$(CONFIG_CONSOLE_PAGER) += pager.o
+
 obj-$(CONFIG_USB_HOST) += usb.o usb_hub.o
 obj-$(CONFIG_USB_GADGET) += usb.o
 obj-$(CONFIG_USB_STORAGE) += usb_storage.o

common/cli_readline.c

@@ -13,6 +13,7 @@
 #include <command.h>
 #include <hang.h>
 #include <malloc.h>
+#include <pager.h>
 #include <time.h>
 #include <watchdog.h>
 #include <linux/errno.h>
@@ -650,6 +651,9 @@ int cli_readline_into_buffer(const char *const prompt, char *buffer,
 	uint len = CONFIG_SYS_CBSIZE;
 	int rc;
 	static int initted;
+	bool old_bypass;
+
+	old_bypass = pager_set_bypass(gd_pager(), true);
 
 	/*
 	 * Say N to CMD_HISTORY_USE_CALLOC will skip runtime
@@ -673,9 +677,14 @@ int cli_readline_into_buffer(const char *const prompt, char *buffer,
 			puts(prompt);
 
 		rc = cread_line(prompt, p, &len, timeout);
-		return rc < 0 ? rc : len;
+		rc = rc < 0 ? rc : len;
 
 	} else {
-		return cread_line_simple(prompt, p);
+		rc = cread_line_simple(prompt, p);
 	}
+
+	pager_set_bypass(gd_pager(), old_bypass);
+	pager_reset(gd_pager());
+
+	return rc;
 }

common/console.c

@@ -16,6 +16,7 @@
 #include <malloc.h>
 #include <mapmem.h>
 #include <os.h>
+#include <pager.h>
 #include <serial.h>
 #include <stdio_dev.h>
 #include <exports.h>
@@ -256,14 +257,22 @@ static int console_tstc(int file)
 	return 0;
 }
 
-static void console_putc(int file, const char c)
-{
-	int i;
-	struct stdio_dev *dev;
+static void console_puts_pager(int file, const char *s);
 
-	for_each_console_dev(i, file, dev) {
-		if (dev->putc != NULL)
-			dev->putc(dev, c);
+static void console_putc_pager(int file, const char c)
+{
+	if (IS_ENABLED(CONFIG_CONSOLE_PAGER) && gd_pager()) {
+		char str[2] = {c, '\0'};
+
+		console_puts_pager(file, str);
+	} else {
+		int i;
+		struct stdio_dev *dev;
+
+		for_each_console_dev(i, file, dev) {
+			if (dev->putc)
+				dev->putc(dev, c);
+		}
 	}
 }
 
@@ -312,14 +321,39 @@ int console_printf_select_stderr(bool serial_only, const char *fmt, ...)
 	return ret;
 }
 
-static void console_puts(int file, const char *s)
+static void console_puts(int file, bool use_pager, const char *s)
 {
-	int i;
-	struct stdio_dev *dev;
+	int key = 0;
 
-	for_each_console_dev(i, file, dev) {
-		if (dev->puts != NULL)
-			dev->puts(dev, s);
+	for (s = pager_post(gd_pager(), use_pager, s); s;
+	     s = pager_next(gd_pager(), use_pager, key)) {
+		struct stdio_dev *dev;
+		int i;
+
+		key = 0;
+		if (IS_ENABLED(CONFIG_CONSOLE_PAGER) && s == PAGER_WAITING) {
+			key = getchar();
+		} else if (*s) {
+			for_each_console_dev(i, file, dev) {
+				if (dev->puts != NULL)
+					dev->puts(dev, s);
+			}
+		}
+	}
+}
+
+static void console_puts_pager(int file, const char *s)
+{
+	if (IS_ENABLED(CONFIG_CONSOLE_PAGER) && gd_pager()) {
+		console_puts(file, true, s);
+	} else {
+		struct stdio_dev *dev;
+		int i;
+
+		for_each_console_dev(i, file, dev) {
+			if (dev->puts != NULL)
+				dev->puts(dev, s);
+		}
 	}
 }
 
@@ -342,7 +376,39 @@ static inline void console_doenv(int file, struct stdio_dev *dev)
 	iomux_doenv(file, dev->name);
 }
 #endif
-#else
+
+/**
+ * sdev_file_has_uclass() - Find a file has a device of a particular uclass
+ *
+ * Given a file, this returns the first device of the given uclass that is found
+ * within that file.
+ *
+ * This only works with driver model
+ *
+ * @file: File to check (e.g. stdout)
+ * @id: uclass ID to look for
+ * Return: device, if found, NULL if not
+ */
+static struct udevice *sdev_file_has_uclass(int file, enum uclass_id id)
+{
+	struct stdio_dev *sdev;
+	int i;
+
+	for_each_console_dev(i, file, sdev) {
+		if (sdev->flags & DEV_FLAGS_DM) {
+			struct udevice *dev = sdev->priv;
+
+			if (device_get_uclass_id(dev) == id)
+				return dev;
+		} else if (id == UCLASS_SERIAL && console_dev_is_serial(sdev)) {
+			return gd->cur_serial_dev;
+		}
+	}
+
+	return NULL;
+}
+
+#else /* !CONSOLE_MUX */
 
 static void console_devices_set(int file, struct stdio_dev *dev)
 {
@@ -368,7 +434,7 @@ static inline int console_tstc(int file)
 	return stdio_devices[file]->tstc(stdio_devices[file]);
 }
 
-static inline void console_putc(int file, const char c)
+static inline void console_putc_pager(int file, const char c)
 {
 	stdio_devices[file]->putc(stdio_devices[file], c);
 }
@@ -380,7 +446,7 @@ void console_puts_select(int file, bool serial_only, const char *s)
 		stdio_devices[file]->puts(stdio_devices[file], s);
 }
 
-static inline void console_puts(int file, const char *s)
+static inline void console_puts_pager(int file, const char *s)
 {
 	stdio_devices[file]->puts(stdio_devices[file], s);
 }
@@ -399,8 +465,52 @@ static inline void console_doenv(int file, struct stdio_dev *dev)
 	console_setfile(file, dev);
 }
 #endif
+
+static inline struct udevice *sdev_file_has_uclass(int file, enum uclass_id id)
+{
+	return NULL;
+}
+
 #endif /* CONIFIG_IS_ENABLED(CONSOLE_MUX) */
 
+int calc_check_console_lines(void)
+{
+	int lines, dev_lines = -1;
+	struct udevice *dev;
+
+	lines = env_get_hex("pager", -1);
+	if (lines != -1)
+		return lines;
+	lines = IF_ENABLED_INT(CONFIG_CONSOLE_PAGER,
+			       CONFIG_CONSOLE_PAGER_LINES);
+
+	/* get number of lines from the video console, if available */
+	if (IS_ENABLED(CONFIG_VIDEO) && video_is_visible()) {
+		dev = sdev_file_has_uclass(stdout, UCLASS_VIDEO_CONSOLE);
+
+		if (dev) {
+			struct vidconsole_priv *priv;
+
+			priv = dev_get_uclass_priv(dev);
+			dev_lines = priv->rows;
+		}
+	}
+	/* get number of lines from the serial console, if available */
+	if (IS_ENABLED(CONFIG_DM_SERIAL) &&
+	    sdev_file_has_uclass(stdout, UCLASS_SERIAL)) {
+		int cols;
+
+		if (!serial_is_tty())
+			dev_lines = 0;
+		else if (dev_lines == -1)
+			serial_query_size(&dev_lines, &cols);
+	}
+	if (dev_lines != -1)
+		lines = dev_lines;
+
+	return lines;
+}
+
 static void __maybe_unused console_setfile_and_devices(int file, struct stdio_dev *dev)
 {
 	console_setfile(file, dev);
@@ -497,13 +607,13 @@ int ftstc(int file)
 void fputc(int file, const char c)
 {
 	if ((unsigned int)file < MAX_FILES)
-		console_putc(file, c);
+		console_putc_pager(file, c);
 }
 
 void fputs(int file, const char *s)
 {
 	if ((unsigned int)file < MAX_FILES)
-		console_puts(file, s);
+		console_puts_pager(file, s);
 }
 
 #ifdef CONFIG_CONSOLE_FLUSH_SUPPORT
@@ -1075,6 +1185,15 @@ static int on_console(const char *name, const char *value, enum env_op op,
 		break;
 	}
 
+	if (IS_ENABLED(CONFIG_CONSOLE_PAGER) && console == stdout) {
+		int lines = calc_check_console_lines();
+
+		/* Set bypass mode if not connected to a terminal */
+		pager_set_bypass(gd_pager(), lines != 0);
+		if (lines)
+			pager_set_page_len(gd_pager(), lines);
+	}
+
 	return result;
 }
 U_BOOT_ENV_CALLBACK(console, on_console);
@@ -1101,6 +1220,19 @@ static int on_silent(const char *name, const char *value, enum env_op op,
 U_BOOT_ENV_CALLBACK(silent, on_silent);
 #endif
 
+static void setup_pager(void)
+{
+	/* Init pager now that console is ready */
+	if (IS_ENABLED(CONFIG_CONSOLE_PAGER)) {
+		int ret;
+
+		ret = pager_init(gd_pagerp(), calc_check_console_lines(),
+				 PAGER_BUF_SIZE);
+		if (ret)
+			printf("Failed to init pager\n");
+	}
+}
+
 #if CONFIG_IS_ENABLED(SYS_CONSOLE_IS_IN_ENV)
 /* Called after the relocation - use desired console functions */
 int console_init_r(void)
@@ -1185,6 +1317,7 @@ done:
 	}
 
 	gd->flags |= GD_FLG_DEVINIT;	/* device initialization completed */
+	setup_pager();
 
 	print_pre_console_buffer(flushpoint);
 	return 0;
@@ -1252,6 +1385,7 @@ int console_init_r(void)
 	}
 
 	gd->flags |= GD_FLG_DEVINIT;	/* device initialization completed */
+	setup_pager();
 
 	print_pre_console_buffer(flushpoint);
 	return 0;

common/pager.c

@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Deals with splitting up text output into separate screenfuls
+ *
+ * Copyright 2025 Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEGORY LOGC_CONSOLE
+
+#include <env.h>
+#include <errno.h>
+#include <malloc.h>
+#include <pager.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+const char *pager_post(struct pager *pag, bool use_pager, const char *s)
+{
+	struct membuf old;
+	int ret, len;
+
+	if (!pag || !use_pager || pag->test_bypass || pag->state == PAGERST_BYPASS)
+		return s;
+
+	len = strlen(s);
+	if (!len)
+		return NULL;
+
+	old = pag->mb;
+	ret = membuf_put(&pag->mb, s, len);
+	if (ret == len) {
+		/* all is well */
+	} else {
+		/*
+		 * We couldn't store any of the text, so we'll store none of
+		 * it. The pager is now in an non-functional state until it
+		 * can eject the overflow text.
+		 *
+		 * The buffer is presumably empty, since callers are not allowed
+		 * to call pager_post() unless all the output from the previous
+		 * call was provided via pager_next().
+		 */
+		pag->overflow = s;
+		pag->mb = old;
+	}
+
+	return pager_next(pag, true, 0);
+}
+
+const char *pager_next(struct pager *pag, bool use_pager, int key)
+{
+	char *str, *p, *end;
+	int ret;
+
+	if (!use_pager || (pag && pag->test_bypass))
+		return NULL;
+
+	/* replace the real character we overwrite with nul, if needed */
+	if (pag->nulch) {
+		*pag->nulch = pag->oldch;
+		pag->nulch = NULL;
+	}
+
+	/* if we're at the limit, wait */
+	switch (pag->state) {
+	case PAGERST_OK:
+		break;
+	case PAGERST_AT_LIMIT:
+		pag->state = PAGERST_WAIT_USER;
+		return PAGER_PROMPT;
+	case PAGERST_WAIT_USER:
+		if (key != ' ')
+			return PAGER_WAITING;
+		pag->state = PAGERST_CLEAR_PROMPT;
+		return PAGER_BLANK;
+	case PAGERST_CLEAR_PROMPT:
+		pag->state = PAGERST_OK;
+		break;
+	case PAGERST_BYPASS:
+		return NULL;
+	}
+
+	ret = membuf_getraw(&pag->mb, pag->buf.size - 1, false, &str);
+	if (!ret) {
+		if (pag->overflow) {
+			const char *oflow = pag->overflow;
+
+			pag->overflow = NULL;
+			return oflow;
+		}
+		return NULL;
+	}
+
+	/* return lines until we reach the limit */
+	for (p = str, end = str + ret; p < end; p++) {
+		if (*p == '\n' && ++pag->line_count == pag->page_len - 1) {
+			/* remember to display the pager message next time */
+			pag->state = PAGERST_AT_LIMIT;
+			pag->line_count = 0;
+
+			/* skip the newline, since our prompt has one */
+			p++;
+			break;
+		}
+	}
+
+	/* remove the used bytes from the membuf */
+	ret = membuf_getraw(&pag->mb, p - str, true, &str);
+
+	/* don't output the newline, since our prompt has one */
+	if (pag->state == PAGERST_AT_LIMIT)
+		p--;
+
+	/* terminate the string */
+	pag->nulch = p;
+	pag->oldch = *pag->nulch;
+	*pag->nulch = '\0';
+
+	return str;
+}
+
+bool pager_set_bypass(struct pager *pag, bool bypass)
+{
+	bool was_bypassed = false;
+
+	if (!pag)
+		return false;
+
+	was_bypassed = pag->state == PAGERST_BYPASS;
+	if (bypass)
+		pag->state = PAGERST_BYPASS;
+	else
+		pag->state = PAGERST_OK;
+
+	return was_bypassed;
+}
+
+bool pager_set_test_bypass(struct pager *pag, bool bypass)
+{
+	bool was_bypassed = false;
+
+	if (!pag)
+		return false;
+
+	was_bypassed = pag->test_bypass;
+	pag->test_bypass = bypass;
+
+	return was_bypassed;
+}
+
+void pager_set_page_len(struct pager *pag, int page_len)
+{
+	if (page_len < 2)
+		return;
+	pag->page_len = page_len;
+	pag->line_count = 0;
+}
+
+void pager_reset(struct pager *pag)
+{
+	pag->line_count = 0;
+}
+
+static int on_pager(const char *name, const char *value, enum env_op op,
+		    int flags)
+{
+	struct pager *pag = gd_pager();
+	int new_page_len;
+
+	if (!IS_ENABLED(CONFIG_CONSOLE_PAGER) || !pag)
+		return 0;
+
+	switch (op) {
+	case env_op_create:
+	case env_op_overwrite:
+		if (value) {
+			new_page_len = simple_strtoul(value, NULL, 16);
+			pager_set_page_len(pag, new_page_len);
+		}
+		break;
+	case env_op_delete:
+		/* Reset to default when deleted */
+		pager_set_page_len(pag, CONFIG_CONSOLE_PAGER_LINES);
+		break;
+	}
+
+	return 0;
+}
+U_BOOT_ENV_CALLBACK(pager, on_pager);
+
+void pager_uninit(struct pager *pag)
+{
+	abuf_uninit(&pag->buf);
+	free(pag);
+}
+
+int pager_init(struct pager **pagp, int page_len, int buf_size)
+{
+	struct pager *pag;
+
+	pag = malloc(sizeof(struct pager));
+	if (!pag)
+		return log_msg_ret("pag", -ENOMEM);
+	memset(pag, '\0', sizeof(struct pager));
+	pag->page_len = page_len;
+	if (!abuf_init_size(&pag->buf, buf_size))
+		return log_msg_ret("pah", -ENOMEM);
+
+	/*
+	 * nul-terminate the buffer, which will come in handy if we need to
+	 * return up to the last byte
+	 */
+	((char *)pag->buf.data)[buf_size - 1] = '\0';
+	membuf_init(&pag->mb, pag->buf.data, buf_size);
+	*pagp = pag;
+
+	return 0;
+}

doc/api/index.rst

@@ -20,6 +20,7 @@ U-Boot API documentation
    lmb
    logging
    nvmem
+   pager
    part
    pinctrl
    rng

doc/api/pager.rst

@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. Copyright Simon Glass <sjg@chromium.org>
+
+Console Pager
+=============
+
+See :doc:`/develop/console`.
+
+.. kernel-doc:: include/pager.h
+   :internal:

doc/develop/console.rst

@@ -0,0 +1,41 @@
+.. SPDX-License-Identifier: GPL-2.0+
+.. sectionauthor:: Simon Glass <sjg@chromium.org>
+
+=======
+Console
+=======
+
+
+Paging
+------
+
+See the user documentation at :doc:`/usage/console`. For the API, see
+:doc:`/api/pager`.
+
+The pager is implemented in `common/pager.c` and integrated into the console
+system via `console_puts()` in `common/console.c`. When output is sent to
+stdout:
+
+1. Text is passed to `pager_post()` which buffers it
+2. `pager_next()` returns portions of text up to the page limit
+3. When the page limit is reached, a prompt is displayed
+4. The system waits for user input (SPACE key) via `getchar()`
+5. After SPACE is pressed, the prompt is cleared and output continues
+
+The pager maintains state through the `struct pager` which tracks:
+
+- Current line count within the page
+- Page length setting
+- Text buffer and overflow handling
+- Current pager state (normal, waiting for user, clearing prompt)
+
+Bypass Mode
+~~~~~~~~~~~
+
+The pager can be put into bypass mode using `pager_set_bypass()`, which is
+useful for automated testing. In bypass mode, all text flows through without
+any paging interruptions.
+
+The pager automatically enters bypass mode when output is not connected to a
+terminal, preventing paging prompts from appearing in non-interactive
+environments like scripts or automated builds.

doc/develop/index.rst

@@ -35,6 +35,7 @@ Implementation
    ci_testing
    commands
    config_binding
+   console
    cyclic
    devicetree/index
    distro

doc/usage/console.rst

@@ -1,15 +1,16 @@
 .. SPDX-License-Identifier: GPL-2.0+
 .. sectionauthor:: Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
 ..  (C) Copyright 2000
+.. sectionauthor:: Simon Glass <sjg@chromium.org>
 
 =======================
 U-Boot console handling
 =======================
 
-HOW THE CONSOLE WORKS?
-----------------------
+Introduction
+------------
 
-At system startup U-Boot initializes a serial console. When U-Boot
+At system-startup U-Boot initializes a serial console. When U-Boot
 relocates itself to RAM, all console drivers are initialized (they
 will register all detected console devices to the system for further
 use).
@@ -17,43 +18,90 @@ use).
 If not defined in the environment, the first input device is assigned
 to the 'stdin' file, the first output one to 'stdout' and 'stderr'.
 
-You can use the command "coninfo" to see all registered console
+You can use the command `coninfo` to see all registered console
 devices and their flags. You can assign a standard file (stdin,
 stdout or stderr) to any device you see in that list simply by
 assigning its name to the corresponding environment variable. For
-example:
+example::
 
-    setenv stdin serial		<- To use the serial input
-    setenv stdout video		<- To use the video console
+    # Use the serial input
+    setenv stdin serial
 
-Do a simple "saveenv" to save the console settings in the environment
+    # Use the video console
+    setenv stdout vidconsole
+
+Do a simple `saveenv` to save the console settings in the environment
 and get them working on the next startup, too.
 
-HOW CAN I USE STANDARD FILE INTO THE SOURCES?
----------------------------------------------
+How to output text to the console
+---------------------------------
 
 You can use the following functions to access the console:
 
-* STDOUT:
-    putc	(to put a char to stdout)
-    puts	(to put a string to stdout)
-    printf	(to format and put a string to stdout)
+stdout
+    - putc() - write a char to stdout
+    - puts() - write a string to stdout
+    - printf() - format and write a string to stdout
 
-* STDIN:
-    tstc	(to test for the presence of a char in stdin)
-    getc	(to get a char from stdin)
+stdin
+    - tstc() - test for the presence of a char in stdin
+    - getchar() - get a char from stdin
 
-* STDERR:
-    eputc	(to put a char to stderr)
-    eputs	(to put a string to stderr)
-    eprintf	(to format and put a string to stderr)
+stderr
+    - eputc() - write a char to stderr
+    - eputs() - write a string to stderr
+    - eprintf() - format and write a string to stderr
 
-* FILE (can be 'stdin', 'stdout', 'stderr'):
-    fputc	(like putc but redirected to a file)
-    fputs	(like puts but redirected to a file)
-    fprintf	(like printf but redirected to a file)
-    ftstc	(like tstc but redirected to a file)
-    fgetc	(like getc but redirected to a file)
+file ('stdin', 'stdout' or 'stderr')
+    - fputc() - write a char to a file
+    - fputs() - write a string to a file
+    - fprintf() - format and write a string to a file
+    - ftstc() - test for the presence of a char in file
+    - fgetc() - get a char from a file
 
-Remember that all FILE-related functions CANNOT be used before
-U-Boot relocation (done in 'board_init_r' in `arch/*/lib/board.c`).
+Remember that FILE-related functions CANNOT be used before U-Boot relocation,
+which is done in `board_init_r()`.
+
+Pager
+-----
+
+U-Boot has a simple pager feature, enabled with `CONFIG_CONSOLE_PAGER`. It is
+only available if `CONFIG_CONSOLE_MUX` is also enabled.
+
+When activated, the pager pauses at the end of each 'page' (screenful) of
+output, shows a prompt ": Press SPACE to continue" and lets the user read the
+output. To continue to the next page, press the SPACE key.
+
+Page Size Configuration
+~~~~~~~~~~~~~~~~~~~~~~~
+
+The number of lines per page is determined in the following order of priority:
+
+1. **Environment variable**: The `pager` environment variable (hex value)
+   takes highest priority. Set to 0 to disable paging.
+
+2. **Video console detection**: If no environment variable is set and a video
+   console is active, the pager uses the number of rows from the video console.
+
+3. **Serial TTY detection**: For serial consoles, the pager checks if the
+   output is connected to a terminal (TTY). If not connected to a TTY, paging
+   is disabled. This check works by sending a few special characters to the
+   terminal and (hopefully) receiving a reply. If you are logging the output of
+   U-Boot, you may see these characters in the log. Disable
+   `CONFIG_SERIAL_TERM_PRESENT` is this is unwanted.
+
+4. **Configuration default**: If none of the above apply, falls back to
+   `CONFIG_CONSOLE_PAGER_LINES`.
+
+Examples::
+
+    # Set page size to 30 lines (hex value 1e)
+    setenv pager 1e
+
+    # Set page size to 24 lines (hex value 18)  
+    setenv pager 18
+
+    # Disable paging
+    setenv pager 0
+
+For developer documentation, please see :doc:`/develop/console`.

doc/usage/environment.rst

@@ -335,6 +335,10 @@ netretry
     Useful on scripts which control the retry operation
     themselves.
 
+pager
+    Decimal number of visible lines on the display, or serial console.
+    :doc:`/usage/console`.
+
 rng_seed_size
     Size of random value added to device-tree node /chosen/rng-seed.
     This variable is given as a decimal number.

drivers/serial/serial-uclass.c

@@ -18,6 +18,9 @@
 #include <asm/global_data.h>
 #include <dm/lists.h>
 #include <dm/device-internal.h>
+#ifdef CONFIG_SANDBOX
+#include <asm/state.h>
+#endif
 #include <dm/of_access.h>
 #include <linux/build_bug.h>
 #include <linux/delay.h>
@@ -647,6 +650,14 @@ int serial_query_size(int *rowsp, int *colsp)
 	if (!CONFIG_IS_ENABLED(SERIAL_TERM_PRESENT))
 		return -ENOENT;
 
+#ifdef CONFIG_SANDBOX
+	if (IS_ENABLED(CONFIG_SANDBOX)) {
+		struct sandbox_state *state = state_get_current();
+		if (state->no_term_present)
+			return -ENOENT;
+	}
+#endif
+
 	/* Empty input buffer */
 	while (tstc())
 		getchar();

include/asm-generic/global_data.h

@@ -24,6 +24,7 @@
 #include <event_internal.h>
 #include <fdtdec.h>
 #include <membuf.h>
+#include <pager.h>
 #include <linux/list.h>
 #include <linux/build_bug.h>
 #include <asm-offsets.h>
@@ -477,6 +478,14 @@ struct global_data {
 	 */
 	struct upl *upl;
 #endif
+#if CONFIG_IS_ENABLED(CONSOLE_PAGER)
+	/**
+	 * @pager: Pointer to the pager settings, or NULL if none
+	 *
+	 * This is set up in console_init_r()
+	 */
+	struct pager *pager;
+#endif
 };
 #ifndef DO_DEPS_ONLY
 static_assert(sizeof(struct global_data) == GD_SIZE);
@@ -618,6 +627,16 @@ static_assert(sizeof(struct global_data) == GD_SIZE);
 #define gd_passage_dtb()	0
 #endif
 
+#if CONFIG_IS_ENABLED(CONSOLE_PAGER)
+#define gd_pager()		gd->pager
+#define gd_pagerp()		&gd->pager
+#define gd_pager_page_len()	gd->pager->page_len
+#else
+#define gd_pager()		NULL
+#define gd_pagerp()		NULL
+#define gd_pager_page_len()	0
+#endif
+
 /**
  * enum gd_flags - global data flags
  *

include/console.h

@@ -202,6 +202,16 @@ int console_clear(void);
  */
 int console_remove_by_name(const char *name);
 
+/**
+ * calc_check_console_lines() - Calculate console page length
+ *
+ * This calculates the appropriate number of lines to use for console paging,
+ * considering environment variables, config defaults, and device capabilities.
+ *
+ * Return: number of lines for paging, or 0 to disable paging
+ */
+int calc_check_console_lines(void);
+
 /*
  * CONSOLE multiplexing.
  */

include/env_callback.h

@@ -75,6 +75,12 @@
 #define DFU_CALLBACK
 #endif
 
+#ifdef CONFIG_CONSOLE_PAGER
+#define PAGER_CALLBACK	"pager:pager,"
+#else
+#define PAGER_CALLBACK
+#endif
+
 /*
  * This list of callback bindings is static, but may be overridden by defining
  * a new association in the ".callbacks" environment variable.
@@ -88,6 +94,7 @@
 	DFU_CALLBACK \
 	"loadaddr:loadaddr," \
 	SILENT_CALLBACK \
+	PAGER_CALLBACK \
 	"stdin:console,stdout:console,stderr:console," \
 	"serial#:serialno," \
 	CFG_ENV_CALLBACK_LIST_STATIC

include/pager.h

@@ -0,0 +1,212 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Deals with splitting up text output into separate screenfuls
+ *
+ * Copyright 2025 Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __PAGER_H
+#define __PAGER_H
+
+#include <stdbool.h>
+#include <abuf.h>
+#include <membuf.h>
+#include <linux/sizes.h>
+
+#define PAGER_BUF_SIZE	SZ_4K
+
+/* Special return value from pager_next() indicating waiting for user input */
+#define PAGER_WAITING	((const char *)1)
+
+/* Prompt shown to user when pager reaches page limit */
+#define PAGER_PROMPT	"\n: Press SPACE to continue"
+
+/* String used to blank/clear the pager prompt */
+#define PAGER_BLANK	"\r                         \r"
+
+/**
+ * enum pager_state: Tracks the state of the pager
+ *
+ * @PAGERST_OK: Normal output is happening
+ * @PAGERST_AT_LIMIT: No more output can be provided; the next call to
+ * pager_next() will return a user prompt
+ * @PAGERST_WAIT_USER: Waiting for the user to press a key
+ * @PAGERST_CLEAR_PROMPT: Clearing the prompt ready for more output
+ * @PAGERST_BYPASS: Pager is being bypassed
+ */
+enum pager_state {
+	PAGERST_OK,
+	PAGERST_AT_LIMIT,
+	PAGERST_WAIT_USER,
+	PAGERST_CLEAR_PROMPT,
+	PAGERST_BYPASS,
+};
+
+/**
+ * struct pager - pager state
+ *
+ * The pager uses a buffer @buf to hold text that it is in the process of
+ * sending out. This helps deal with the stdio puts() interface, which does not
+ * permit passing a string length, only a string, which means that strings must
+ * be nul-terminated. The termination is handled automatically by the pager.
+ *
+ * If the text passed to pager_post() is too large for @buf then all the next
+ * will be written at once, without any paging, in the next call to
+ * pager_next().
+ *
+ * The membuf @mb is only used to feed out text in chunks, with a pager message
+ * (and a keypress wait) inserted between each chunk.
+ *
+ * @line_count: Number of lines output since last pause
+ * @page_len: Sets the height of the page in lines. The maximum lines to display
+ * before pausing is one less than this. Set from 'pager' env variable
+ * @buf: Buffer containing text to eventually be returned
+ * @mb: Circular buffer to manage @buf
+ * @overflow: pointer to overflow text to send nexts
+ * @nulch: pointer to where a nul character was written, NULL if none
+ * @oldch: old character that was at @nulch
+ * @state: current state of the pager state-machine
+ * @test_bypass: true if pager should behave as if in test mode (bypass all)
+ */
+struct pager {
+	int line_count;
+	int page_len;
+	struct abuf buf;
+	struct membuf mb;
+	const char *overflow;
+	char *nulch;
+	int oldch;
+	enum pager_state state;
+	bool test_bypass;
+};
+
+#if CONFIG_IS_ENABLED(CONSOLE_PAGER)
+
+/**
+ * pager_post() - Add text to the input buffer for later handling
+ *
+ * If @use_pager the text is added to the pager buffer and fed out a screenful
+ * at a time. This function calls pager_post() after storing the text.
+ *
+ * After calling pager_post(), if it returns anything other than NULL, you must
+ * repeatedly call pager_next() until it returns NULL, otherwise text may be
+ * lost
+ *
+ * If @pag is NULL, this does nothing but return @s
+ *
+ * @pag: Pager to use, may be NULL
+ * @use_pager: Whether or not to use the pager functionality
+ * @s: Text to add
+ * Return: text which should be sent to output, or NULL if there is no more.
+ * If !@use_pager this just returns @s and does not affect the pager state
+ */
+const char *pager_post(struct pager *pag, bool use_pager, const char *s);
+
+/**
+ * pager_next() - Returns the next screenful of text to show
+ *
+ * If this function returns PAGER_WAITING then the caller must check for user
+ * input and pass in the keypress in the next call to pager_next(). It can
+ * busy-wait for a keypress, if desired, since pager_next() will only ever
+ * return PAGER_WAITING until @ch is non-zero.
+ *
+ * @pag: Pager to use
+ * @use_pager: Whether or not to use the pager functionality
+ * @ch: Key that the user has pressed, or 0 if none
+ *
+ * Return: text which should be sent to output, or PAGER_WAITING if waiting for
+ * the user to press a key, or NULL if there is no more text.
+ * If !@use_pager this just returns NULL and does not affect the pager state
+ */
+const char *pager_next(struct pager *pag, bool use_pager, int ch);
+
+/**
+ * pager_set_bypass() - put the pager into bypass mode
+ *
+ * This is used when output is not connected to a terminal. Bypass mode stops
+ * the pager from doing anything to interrupt output.
+ *
+ * @pag: Pager to use, may be NULL in which case this function does nothing
+ * @bypass: true to put the pager in bypass mode, false for normal mode
+ * Return: old value of the bypass flag
+ */
+bool pager_set_bypass(struct pager *pag, bool bypass);
+
+/**
+ * pager_set_test_bypass() - put the pager into test bypass mode
+ *
+ * This is used for tests. Test bypass mode stops the pager from doing
+ * anything to interrupt output, regardless of the current pager state.
+ *
+ * @pag: Pager to use, may be NULL in which case this function does nothing
+ * @bypass: true to put the pager in test bypass mode, false for normal
+ * Return: old value of the test bypass flag
+ */
+bool pager_set_test_bypass(struct pager *pag, bool bypass);
+
+/**
+ * pager_reset() - reset the line count in the pager
+ *
+ * Sets line_count to zero so that the pager starts afresh with its counting.
+ *
+ * @pag: Pager to update
+ */
+void pager_reset(struct pager *pag);
+
+/**
+ * pager_uninit() - Uninit the pager
+ *
+ * Frees all memory and also @pag
+ *
+ * @pag: Pager to uninit
+ */
+void pager_uninit(struct pager *pag);
+
+#else
+static inline const char *pager_post(struct pager *pag, bool use_pager,
+				     const char *s)
+{
+	return s;
+}
+
+static inline const char *pager_next(struct pager *pag, bool use_pager, int ch)
+{
+	return NULL;
+}
+
+static inline bool pager_set_bypass(struct pager *pag, bool bypass)
+{
+	return true;
+}
+
+static inline bool pager_set_test_bypass(struct pager *pag, bool bypass)
+{
+	return true;
+}
+
+static inline void pager_reset(struct pager *pag)
+{
+}
+
+#endif
+
+/**
+ * pager_set_page_len() - Set the page length of a pager
+ *
+ * @pag: Pager to use
+ * @page_len: Page length to set
+ */
+void pager_set_page_len(struct pager *pag, int page_len);
+
+/**
+ * pager_init() - Set up a new pager
+ *
+ * @pagp: Returns allocaed pager, on success
+ * @page_len: Number of lines per page
+ * @buf_size: Buffer size to use in bytes, this is the maximum amount of output
+ * that can be paged
+ * Return: 0 if OK, -ENOMEM if out of memory
+ */
+int pager_init(struct pager **pagp, int page_len, int buf_size);
+
+#endif

include/serial.h

@@ -406,8 +406,8 @@ int serial_tstc(void);
  * When using a serial console or the net console we can only devise the
  * terminal size by querying the terminal using ECMA-48 control sequences.
  *
- * @rowsp:	returns number of rows
- * @colsp:	returns number of columns
+ * @rowsp:	returns number of rows on success
+ * @colsp:	returns number of columns on success
  * Returns:	0 on success, -NOENT if no terminal is present, -ETIMEDOUT if we
  * checked for a terminal but didn't get a response in time, -EPROTO if the
  * terminal did not respond as expected

lib/efi_client/Kconfig

@@ -22,6 +22,7 @@ config EFI_APP
 	depends on X86 || ARM
 	select CHARSET
 	select EVENT
+	imply CONSOLE_PAGER
 	help
 	  Build U-Boot as an application which can be started from EFI. This
 	  is useful for examining a platform in the early stages of porting

test/cmd/bdinfo.c

@@ -184,6 +184,9 @@ static int bdinfo_test_all(struct unit_test_state *uts)
 	if (IS_ENABLED(CONFIG_VIDEO))
 		ut_assertok(test_video_info(uts));
 
+	if (IS_ENABLED(CONFIG_CONSOLE_PAGER))
+		ut_assert_nextline("pager       = %d", gd_pager_page_len());
+
 	/* The gd->multi_dtb_fit may not be available, hence, #if below. */
 #if CONFIG_IS_ENABLED(MULTI_DTB_FIT)
 	ut_assertok(test_num_l(uts, "multi_dtb_fit", (ulong)gd->multi_dtb_fit));

test/common/Makefile

@@ -7,7 +7,9 @@ obj-$(CONFIG_$(PHASE_)CMDLINE) += bloblist.o
 endif
 endif
 
+obj-$(CONFIG_CONSOLE_PAGER) += console.o
 obj-$(CONFIG_CYCLIC) += cyclic.o
 obj-$(CONFIG_EVENT_DYNAMIC) += event.o
 obj-y += cread.o
+obj-$(CONFIG_CONSOLE_PAGER) += pager.o
 obj-$(CONFIG_$(PHASE_)CMDLINE) += print.o

test/common/console.c

@@ -0,0 +1,183 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2025 Simon Glass <sjg@chromium.org>
+ *
+ * Test for console functionality
+ */
+
+#include <console.h>
+#include <env.h>
+#include <malloc.h>
+#include <serial.h>
+#include <video.h>
+#include <test/common.h>
+#include <test/test.h>
+#include <test/ut.h>
+#include <asm/global_data.h>
+#include <asm/state.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Test calc_check_console_lines() with environment variable override */
+static int console_test_calc_lines_env_override(struct unit_test_state *uts)
+{
+	int original_lines, lines;
+	char *orig_env;
+
+	/* Save original environment value */
+	orig_env = env_get("pager");
+	original_lines = calc_check_console_lines();
+
+	/* Test with hex environment variable */
+	ut_assertok(env_set("pager", "1a"));  /* 26 in hex */
+	lines = calc_check_console_lines();
+	ut_asserteq(26, lines);
+
+	/* Test with decimal-looking hex value */
+	ut_assertok(env_set("pager", "20"));  /* 32 in hex */
+	lines = calc_check_console_lines();
+	ut_asserteq(32, lines);
+
+	/* Test with zero (should disable pager) */
+	ut_assertok(env_set("pager", "0"));
+	lines = calc_check_console_lines();
+	ut_asserteq(0, lines);
+
+	/* Restore original environment */
+	ut_assertok(env_set("pager", orig_env));
+
+	/* Verify restoration */
+	lines = calc_check_console_lines();
+	ut_asserteq(original_lines, lines);
+
+	return 0;
+}
+COMMON_TEST(console_test_calc_lines_env_override, 0);
+
+/* Test calc_check_console_lines() with invalid environment values */
+static int console_test_calc_lines_env_invalid(struct unit_test_state *uts)
+{
+	int original_lines, lines;
+	char *orig_env;
+
+	/* Save original environment value */
+	orig_env = env_get("pager");
+	original_lines = calc_check_console_lines();
+
+	/* Test with invalid hex value - should fall back to default */
+	ut_assertok(env_set("pager", "xyz"));
+	lines = calc_check_console_lines();
+	/* Should return default since 'pager' reads as 0 */
+	ut_asserteq(CONFIG_CONSOLE_PAGER_LINES, lines);
+
+	/* Test with empty string */
+	ut_assertok(env_set("pager", ""));
+	lines = calc_check_console_lines();
+	ut_asserteq(CONFIG_CONSOLE_PAGER_LINES, lines);
+
+	/* Restore original environment */
+	ut_assertok(env_set("pager", orig_env));
+
+	return 0;
+}
+COMMON_TEST(console_test_calc_lines_env_invalid, 0);
+
+/* Test calc_check_console_lines() default behavior without environment */
+static int console_test_calc_lines_default(struct unit_test_state *uts)
+{
+	int lines;
+	char *orig_env;
+
+	/* Save and clear environment variable */
+	orig_env = env_get("pager");
+	ut_assertok(env_set("pager", NULL));
+
+	/* Get default behavior */
+	lines = calc_check_console_lines();
+
+	/*
+	 * The function considers device detection (video/serial) which may
+	 * override the CONFIG default. In sandbox, serial_is_tty() may return
+	 * false during tests, causing the function to return 0. Just verify it
+	 * returns a reasonable value.
+	 */
+	ut_assert(lines >= 0);
+
+	/* If CONFIG_CONSOLE_PAGER is not enabled, should definitely be 0 */
+	if (!IS_ENABLED(CONFIG_CONSOLE_PAGER)) {
+		ut_asserteq(0, lines);
+	}
+
+	/* Restore original environment */
+	ut_assertok(env_set("pager", orig_env));
+
+	return 0;
+}
+COMMON_TEST(console_test_calc_lines_default, 0);
+
+/* Test calc_check_console_lines() precedence: env overrides everything */
+static int console_test_calc_lines_precedence(struct unit_test_state *uts)
+{
+	int lines;
+	char *orig_env;
+
+	/* Save original environment value */
+	orig_env = env_get("pager");
+
+	/* Set environment to a specific value */
+	ut_assertok(env_set("pager", "2a"));  /* 42 in hex */
+	lines = calc_check_console_lines();
+	
+	/*
+	 * Environment should always take precedence regardless of video/serial
+	 * state
+	 */
+	ut_asserteq(42, lines);
+
+	/* Test with zero environment value */
+	ut_assertok(env_set("pager", "0"));
+	lines = calc_check_console_lines();
+	ut_asserteq(0, lines);
+
+	/* Restore original environment */
+	ut_assertok(env_set("pager", orig_env));
+
+	return 0;
+}
+COMMON_TEST(console_test_calc_lines_precedence, 0);
+
+/* Test calc_check_console_lines() with serial TTY detection */
+static int console_test_calc_lines_serial_tty(struct unit_test_state *uts)
+{
+	int lines;
+	char *orig_env;
+	bool orig_tty;
+	struct sandbox_state *state;
+
+	/* Save original state */
+	orig_env = env_get("pager");
+	state = state_get_current();
+	orig_tty = state->serial_is_tty;
+
+	/* Clear environment to test device detection */
+	ut_assertok(env_set("pager", NULL));
+
+	/* Test with serial TTY enabled */
+	state->serial_is_tty = true;
+	lines = calc_check_console_lines();
+	/* Should attempt to query serial size or use default */
+	ut_assert(lines >= 0);
+
+	/* Test with serial TTY disabled (not a terminal) */
+	state->serial_is_tty = false;
+	lines = calc_check_console_lines();
+	/* Should return 0 when not connected to TTY */
+	ut_asserteq(0, lines);
+
+	/* Restore original state */
+	state->serial_is_tty = orig_tty;
+	ut_assertok(env_set("pager", orig_env));
+
+	return 0;
+}
+COMMON_TEST(console_test_calc_lines_serial_tty, 0);

test/common/pager.c

@@ -0,0 +1,580 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2025 Simon Glass <sjg@chromium.org>
+ *
+ * Test for pager functionality
+ */
+
+#include <errno.h>
+#include <malloc.h>
+#include <pager.h>
+#include <string.h>
+#include <test/common.h>
+#include <test/test.h>
+#include <test/ut.h>
+#include <asm/global_data.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Test basic pager init and cleanup */
+static int pager_test_basic_init(struct unit_test_state *uts)
+{
+	struct pager *pag;
+
+	/* Test successful init */
+	ut_assertok(pager_init(&pag, 20, 1024));
+	ut_assertnonnull(pag);
+	ut_asserteq(20, pag->page_len);
+	ut_asserteq(0, pag->line_count);
+	ut_assertnull(pag->overflow);
+	ut_assertnull(pag->nulch);
+
+	/* Clean up */
+	pager_uninit(pag);
+
+	/* Test init with different parameters */
+	ut_assertok(pager_init(&pag, 10, 2048));
+	ut_assertnonnull(pag);
+	ut_asserteq(10, pag->page_len);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_basic_init, 0);
+
+/* Test pager with simple text */
+static int pager_test_simple_text(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *text = "Hello, World!";
+	const char *result;
+
+	ut_assertok(pager_init(&pag, 20, 1024));
+
+	/* Post some text and get it back */
+	result = pager_post(pag, true, text);
+	ut_assertnonnull(result);
+	ut_asserteq_str(text, result);
+
+	/* Should be no more text */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_simple_text, 0);
+
+/* Test pager with multiple lines */
+static int pager_test_multiline(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *text1 = "Line 1\n";
+	const char *text2 = "Line 2\n";
+	const char *text3 = "Line 3\n";
+	const char *result;
+	ulong start;
+
+	start = ut_check_free();
+
+	ut_assertok(pager_init(&pag, 20, 1024));
+
+	/* Post multiple pieces of text */
+	result = pager_post(pag, true, text1);
+	ut_assertnonnull(result);
+	ut_asserteq_str(text1, result);
+
+	/* Should be no more text after first post */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	result = pager_post(pag, true, text2);
+	ut_assertnonnull(result);
+	ut_asserteq_str(text2, result);
+
+	/* Should be no more text after second post */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	result = pager_post(pag, true, text3);
+	ut_assertnonnull(result);
+	ut_asserteq_str(text3, result);
+
+	/* Should be no more text after third post */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	/* Check for memory leaks */
+	ut_assertok(ut_check_delta(start));
+
+	return 0;
+}
+COMMON_TEST(pager_test_multiline, 0);
+
+/* Test pager with large text that fills the buffer */
+static int pager_test_large_text(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *result;
+
+	ut_assertok(pager_init(&pag, 20, 16)); /* Small buffer */
+
+	/* Post large text - should fit in buffer */
+	result = pager_post(pag, true, "this is 16 chars");
+	ut_assertnonnull(result);
+	ut_asserteq_str("this is 16 chars", result);
+	ut_assertnull(pager_next(pag, true, 0));
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_large_text, 0);
+
+/* Test pager overflow handling */
+static int pager_test_overflow(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *result;
+
+	ut_assertok(pager_init(&pag, 20, 4)); /* Small buffer */
+
+	/* send some text which is too long for the buffer */
+	result = pager_post(pag, true, "test1");
+	ut_assertnonnull(result);
+
+	/* overflow handling should return the text */
+	ut_asserteq_str("test1", result);
+	ut_assertnull(pager_next(pag, true, 0));
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_overflow, 0);
+
+/* Test pager with NULL input */
+static int pager_test_null_input(struct unit_test_state *uts)
+{
+	const char *result;
+
+	/* Test pager_post with NULL pager */
+	result = pager_post(NULL, true, "test");
+	ut_asserteq_str("test", result);
+
+	return 0;
+}
+COMMON_TEST(pager_test_null_input, 0);
+
+/* Test pager with empty strings */
+static int pager_test_empty_strings(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *result;
+
+	ut_assertok(pager_init(&pag, 20, 1024));
+
+	/* Post empty string */
+	result = pager_post(pag, true, "");
+	ut_assertnull(result);
+
+	/* Should be no more text */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_empty_strings, 0);
+
+/* Test pager buffer management */
+static int pager_test_buffer_management(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *text = "Test buffer management";
+	const char *result;
+
+	ut_assertok(pager_init(&pag, 20, 1024));
+
+	/* Verify buffer is properly inited */
+	ut_assertnonnull(pag->buf.data);
+	ut_asserteq(1024, pag->buf.size);
+
+	/* Post text and verify buffer state */
+	result = pager_post(pag, true, text);
+	ut_assertnonnull(result);
+
+	/* Verify the buffer contains our text */
+	ut_asserteq_str(text, result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_buffer_management, 0);
+
+/* Test pager with very long single line */
+static int pager_test_long_single_line(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	char long_line[1000];
+	const char *result;
+
+	ut_assertok(pager_init(&pag, 20, 1024));
+
+	/* Create a very long line without newlines */
+	memset(long_line, 'X', sizeof(long_line) - 1);
+	long_line[sizeof(long_line) - 1] = '\0';
+
+	/* Post the long line */
+	result = pager_post(pag, true, long_line);
+	ut_assertnonnull(result);
+
+	/* Should get our text back */
+	ut_asserteq_str(long_line, result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_long_single_line, 0);
+
+/* Test pager line counting and page breaks */
+static int pager_test_line_counting(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *multiline_text = "Line 1\nLine 2\nLine 3\nLine 4\nLine 5\n";
+	const char *result;
+
+	/* Init with page length of 4 lines */
+	ut_assertok(pager_init(&pag, 4, 1024));
+
+	/* Post multiline text */
+	result = pager_post(pag, true, multiline_text);
+	ut_assertnonnull(result);
+
+	/* Should get first 3 lines (excluding the 3rd newline) */
+	ut_asserteq_str("Line 1\nLine 2\nLine 3", result);
+	/* line_count is reset to 0 when page limit is reached */
+	ut_asserteq(0, pag->line_count);
+
+	/* Next call should return pager prompt */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_PROMPT, result);
+
+	/* Press space to continue */
+	result = pager_next(pag, true, ' ');
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_BLANK, result);
+
+	/* Get remaining lines */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	ut_asserteq_str("Line 4\nLine 5\n", result);
+
+	/* Should be no more text */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_line_counting, 0);
+
+/* Test that PAGER_WAITING is returned when pager waits for user input */
+static int pager_test_pager_waiting(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *result;
+
+	/* Create pager with small page size to trigger waiting quickly */
+	ut_assertok(pager_init(&pag, 3, 1024));
+
+	/* Post text that fills exactly the page limit */
+	result = pager_post(pag, true, "Line 1\nLine 2\n");
+	ut_assertnonnull(result);
+	ut_asserteq_str("Line 1\nLine 2", result);
+
+	/* Next call should return the prompt */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_PROMPT, result);
+
+	/* Next call without space key should return PAGER_WAITING */
+	result = pager_next(pag, true, 0);
+	ut_asserteq_ptr(PAGER_WAITING, result);
+
+	/* Another call without space should still return PAGER_WAITING */
+	result = pager_next(pag, true, 'x');  /* Wrong key */
+	ut_asserteq_ptr(PAGER_WAITING, result);
+
+	/* Pressing space should clear the prompt */
+	result = pager_next(pag, true, ' ');
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_BLANK, result);
+
+	/* Now should return NULL (no more content) */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_pager_waiting, 0);
+
+/* Test use_pager parameter - output text directly, while buffer is non-empty */
+static int pager_test_use_pager_param(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *buffered_text = "Line 1\nLine 2\nLine 3\nLine 4\nLine 5\n";
+	const char *direct_text = "This should be written immediately";
+	const char *result;
+
+	/* Init with small page length to ensure paging occurs */
+	ut_assertok(pager_init(&pag, 3, 1024));
+
+	/* Post text with use_pager=true - should trigger paging */
+	result = pager_post(pag, true, buffered_text);
+	ut_assertnonnull(result);
+	/* Should get first 2 lines */
+	ut_asserteq_str("Line 1\nLine 2", result);
+
+	/* Now call pager_post with use_pager=false while text is still buffered */
+	result = pager_post(pag, false, direct_text);
+	/* Should get the text immediately, not from buffer */
+	ut_asserteq_ptr(direct_text, result);
+
+	/* Call pager_next with use_pager=false - should return NULL */
+	result = pager_next(pag, false, 0);
+	ut_assertnull(result);
+
+	/* Now continue with use_pager=true to get buffered text */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	/* Should get the pager prompt */
+	ut_asserteq_str(PAGER_PROMPT, result);
+
+	/* Press space to continue */
+	result = pager_next(pag, true, ' ');
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_BLANK, result);
+
+	/* Get remaining buffered lines - should be next 2 lines due to page limit */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	ut_asserteq_str("Line 3\nLine 4", result);
+
+	/* Should get pager prompt again */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_PROMPT, result);
+
+	/* Press space to continue */
+	result = pager_next(pag, true, ' ');
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_BLANK, result);
+
+	/* Get final line */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	ut_asserteq_str("Line 5\n", result);
+
+	/* Should be no more text */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_use_pager_param, 0);
+
+/* Test pager bypass mode */
+static int pager_test_bypass_mode(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *text = "This text should be returned directly";
+	const char *result;
+
+	/* Init with small page length to ensure paging would normally occur */
+	ut_assertok(pager_init(&pag, 2, 1024));
+
+	/* Enable bypass mode */
+	pager_set_test_bypass(pag, true);
+
+	/* Post text - should get original string back directly */
+	result = pager_post(pag, true, text);
+	ut_asserteq_ptr(text, result); /* Should be same pointer */
+
+	/* pager_next should return NULL in bypass mode */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	/* Disable bypass mode */
+	pager_set_test_bypass(pag, false);
+
+	/* Now pager should work normally */
+	result = pager_post(pag, true, text);
+	ut_assertnonnull(result);
+	/* In normal mode, result should be different from original text */
+	ut_assert(result != text);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_bypass_mode, 0);
+
+/* Test that single character output via putc goes through pager */
+static int pager_test_putc(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *result;
+
+	/* Init pager */
+	ut_assertok(pager_init(&pag, 20, 1024));
+	pager_set_bypass(pag, true);
+
+	/*
+	 * Test that individual characters can be posted via pager API
+	 * This verifies that console_putc_pager() routes through the pager
+	 * system
+	 */
+	result = pager_post(pag, true, "A");
+	ut_asserteq_ptr("A", result); /* Bypass mode returns original pointer */
+
+	result = pager_post(pag, true, "\n");
+	ut_asserteq_ptr("\n", result);
+
+	result = pager_post(pag, true, "B");
+	ut_asserteq_ptr("B", result);
+
+	/* Disable bypass to test normal functionality with single chars */
+	pager_set_bypass(pag, false);
+
+	result = pager_post(pag, true, "X");
+	ut_assertnonnull(result);
+	ut_asserteq_str("X", result);
+
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_putc, 0);
+
+/* Test writing up to page limit then adding final newline */
+static int pager_test_limit_plus_newline(struct unit_test_state *uts)
+{
+	struct pager *pag;
+	const char *result;
+
+	/* Init with page length of 3 lines */
+	ut_assertok(pager_init(&pag, 3, 1024));
+
+	/* Write text that reaches exactly the page limit (2 newlines) */
+	result = pager_post(pag, true, "Line 1\nLine 2");
+	ut_assertnonnull(result);
+	ut_asserteq_str("Line 1\nLine 2", result);
+	ut_asserteq(1, pag->line_count); /* Should have 1 line counted */
+
+	/* Should be no more text yet - haven't hit limit */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	/* Now post a single newline - this should trigger the page limit */
+	result = pager_post(pag, true, "\n");
+	ut_assertnonnull(result);
+	/*
+	 * Should get empty string since we hit the limit and the newline is
+	 * consumed
+	 */
+	ut_asserteq_str("", result);
+
+	/* Next call should return the pager prompt since we hit the limit */
+	result = pager_next(pag, true, 0);
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_PROMPT, result);
+
+	/* Press space to continue */
+	result = pager_next(pag, true, ' ');
+	ut_assertnonnull(result);
+	ut_asserteq_str(PAGER_BLANK, result);
+
+	/* Should be no more text */
+	result = pager_next(pag, true, 0);
+	ut_assertnull(result);
+
+	pager_uninit(pag);
+
+	return 0;
+}
+COMMON_TEST(pager_test_limit_plus_newline, 0);
+
+/* Test console integration - pager prompt appears in console output */
+static int pager_test_console(struct unit_test_state *uts)
+{
+	struct pager *pag, *orig_pag;
+	char line[100];
+	int avail, ret;
+
+	/* Save original pager */
+	orig_pag = gd_pager();
+
+	/* Create our own pager for testing */
+	ret = pager_init(&pag, 2, 1024);
+	if (ret) {
+		gd->pager = orig_pag;
+		return CMD_RET_FAILURE;
+	}
+
+	/* Set up pager to be one away from limit (1 line already counted) */
+	pag->line_count = 1;
+
+	/* Assign our pager to the global data */
+	gd->pager = pag;
+
+	/* Trigger paging with a second newline */
+	putc('\n');
+
+	/* Check if there's any console output available at all */
+	avail = console_record_avail();
+
+	/* Restore original pager first */
+	gd->pager = orig_pag;
+	pager_uninit(pag);
+
+	/* Now check what we got */
+	if (!avail) {
+		ut_reportf("No console output was recorded at all");
+		return CMD_RET_FAILURE;
+	}
+
+	/* Try to read the actual output */
+	ret = console_record_readline(line, sizeof(line));
+	if (ret < 0) {
+		ut_reportf("Failed to read first line, avail was %d", avail);
+		return CMD_RET_FAILURE;
+	}
+
+	/*
+	 * console recording does not see the pager prompt, so we should have
+	 * just got a newline
+	 */
+	ut_asserteq_str("", line);
+
+	ut_assert_console_end();
+
+	return 0;
+}
+COMMON_TEST(pager_test_console, UTF_CONSOLE);

test/py/console_sandbox.py

@@ -52,6 +52,13 @@ class ConsoleSandbox(ConsoleBase):
         if self.use_dtb:
             cmd += ['-d', self.config.dtb]
         cmd += self.sandbox_flags
+
+        # Always disable the pager
+        cmd.append('-P')
+
+        # Always disable detected the terminal size
+        cmd.append('-A')
+
         return Spawn(cmd, cwd=self.config.source_dir, decode_signal=True)
 
     def restart_uboot_with_flags(self, flags, use_dtb=True):

test/test-main.c

@@ -14,6 +14,7 @@
 #include <net.h>
 #include <of_live.h>
 #include <os.h>
+#include <pager.h>
 #include <spl.h>
 #include <usb.h>
 #include <dm/ofnode.h>
@@ -747,8 +748,10 @@ int ut_run_list(struct unit_test_state *uts, const char *category,
 		memcpy(uts->fdt_copy, gd->fdt_blob, uts->fdt_size);
 	}
 	uts->force_run = force_run;
+	pager_set_test_bypass(gd_pager(), true);
 	ret = ut_run_tests(uts, prefix, tests, count, select_name,
 			   test_insert);
+	pager_set_test_bypass(gd_pager(), false);
 
 	/* Best efforts only...ignore errors */
 	if (has_dm_tests)