cyclic: Add 'cyclic list' and 'cyclic demo' commands

This patch adds the cyclic command, which currently only supports the
'list' subcommand, to list all currently registered cyclic functions.
Here an example:

=> cyclic list
function: cyclic_demo, cpu-time: 7010 us, frequency: 99.80 times/s
function: cyclic_demo2, cpu-time: 1 us, frequency: 1.13 times/s

As you can see, the cpu-time is accounted, so that cyclic functions
that take too long might be discovered. Additionally the frequency is
logged.

The 'cyclic demo' commands registers the cyclic_demo() function to
be executed all 'cycletime_ms' milliseconds. The only thing this
function does is delaying by 'delay_us' microseconds.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

MAINTAINERS

@@ -798,6 +798,7 @@ F:	doc/arch/m68k.rst
 CYCLIC
 M:	Stefan Roese <sr@denx.de>
 S:	Maintained
+F:	cmd/cyclic.c
 F:	common/cyclic.c
 F:	include/cyclic.h
 

cmd/Kconfig

@@ -2511,6 +2511,22 @@ config CMD_CBSYSINFO
 	  memory by coreboot before jumping to U-Boot. It can be useful for
 	  debugging the beaaviour of coreboot or U-Boot.
 
+config CMD_CYCLIC
+	bool "cyclic - Show information about cyclic functions"
+	depends on CYCLIC
+	default y
+	help
+	  This enables the 'cyclic' command which provides information about
+	  cyclic execution functions. This infrastructure allows registering
+	  functions to be executed cyclically, e.g. every 100ms. These commands
+	  are supported:
+
+	    cyclic list - list cyclic functions
+	    cyclic cyclic demo <cycletime_ms> <delay_us> - register cyclic
+		demo function
+
+	  See doc/develop/cyclic.rst for more details.
+
 config CMD_DIAG
 	bool "diag - Board diagnostics"
 	help

cmd/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_CMD_DIAG) += diag.o
 endif
 obj-$(CONFIG_CMD_ADTIMG) += adtimg.o
 obj-$(CONFIG_CMD_ABOOTIMG) += abootimg.o
+obj-$(CONFIG_CMD_CYCLIC) += cyclic.o
 obj-$(CONFIG_CMD_EVENT) += event.o
 obj-$(CONFIG_CMD_EXTENSION) += extension_board.o
 obj-$(CONFIG_CMD_ECHO) += echo.o

cmd/cyclic.c

@@ -0,0 +1,84 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * A general-purpose cyclic execution infrastructure, to allow "small"
+ * (run-time wise) functions to be executed at a specified frequency.
+ * Things like LED blinking or watchdog triggering are examples for such
+ * tasks.
+ *
+ * Copyright (C) 2022 Stefan Roese <sr@denx.de>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <cyclic.h>
+#include <div64.h>
+#include <malloc.h>
+#include <linux/delay.h>
+
+struct cyclic_demo_info {
+	uint delay_us;
+};
+
+static void cyclic_demo(void *ctx)
+{
+	struct cyclic_demo_info *info = ctx;
+
+	/* Just a small dummy delay here */
+	udelay(info->delay_us);
+}
+
+static int do_cyclic_demo(struct cmd_tbl *cmdtp, int flag, int argc,
+			  char *const argv[])
+{
+	struct cyclic_demo_info *info;
+	struct cyclic_info *cyclic;
+	uint time_ms;
+
+	if (argc < 3)
+		return CMD_RET_USAGE;
+
+	info = malloc(sizeof(struct cyclic_demo_info));
+	if (!info) {
+		printf("out of memory\n");
+                return CMD_RET_FAILURE;
+	}
+
+	time_ms = simple_strtoul(argv[1], NULL, 0);
+	info->delay_us = simple_strtoul(argv[2], NULL, 0);
+
+	/* Register demo cyclic function */
+	cyclic = cyclic_register(cyclic_demo, time_ms * 1000, "cyclic_demo",
+				 info);
+	if (!cyclic)
+		printf("Registering of cyclic_demo failed\n");
+
+	printf("Registered function \"%s\" to be executed all %dms\n",
+	       "cyclic_demo", time_ms);
+
+	return 0;
+}
+
+static int do_cyclic_list(struct cmd_tbl *cmdtp, int flag, int argc,
+			  char *const argv[])
+{
+	struct cyclic_info *cyclic, *tmp;
+	u64 cnt, freq;
+
+	list_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list) {
+		cnt = cyclic->run_cnt * 1000000ULL * 100ULL;
+		freq = lldiv(cnt, timer_get_us() - cyclic->start_time_us);
+		printf("function: %s, cpu-time: %lld us, frequency: %lld.%02d times/s\n",
+		       cyclic->name, cyclic->cpu_time_us,
+		       lldiv(freq, 100), do_div(freq, 100));
+	}
+
+	return 0;
+}
+
+static char cyclic_help_text[] =
+	"cyclic demo <cycletime_ms> <delay_us> - register cyclic demo function\n"
+	"cyclic list - list cyclic functions\n";
+
+U_BOOT_CMD_WITH_SUBCMDS(cyclic, "Cyclic", cyclic_help_text,
+	U_BOOT_SUBCMD_MKENT(demo, 3, 1, do_cyclic_demo),
+	U_BOOT_SUBCMD_MKENT(list, 1, 1, do_cyclic_list));