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008c4b3c31
There are of course not a whole lot of examples in-tree yet, but
before they appear, let's make this API change: Instead of separately
allocating a 'struct cyclic_info', make the users embed such an
instance in their own structure, and make the convention that the
callback simply receives the 'struct cyclic_info *', from which the
clients can get their own data using the container_of() macro.
This has a number of advantages.
First, it means cyclic_register() simply cannot fail, simplifying the
code. The necessary storage will simply be allocated automatically
when the client's own structure is allocated (often via
uclass_priv_auto or similar).
Second, code for which CONFIG_CYCLIC is just an option can more easily
be written without #ifdefs, if we just provide an empty struct
cyclic_info {}. For example, the nested CONFIG_IS_ENABLED()s in
https://lore.kernel.org/u-boot/20240316201416.211480-1-marek.vasut+renesas@mailbox.org/
are mostly due to the existence of the 'struct cyclic_info *' member
being guarded by #ifdef CONFIG_CYCLIC.
And we do probably want to avoid the extra memory overhead of that
member when !CONFIG_CYCLIC. But that is automatic if, instead of a
'struct cyclic_info *', one simply embeds a 'struct cyclic_info',
which will have size 0 when !CONFIG_CYCLIC. Also, the no-op
cyclic_register() function can just unconditionally be called, and the
compiler will see that (1) the callback is referenced, so not emit a
warning for a maybe-unused function and (2) see that it can actually
never be reached, so not emit any code for it.
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* A general-purpose cyclic execution infrastructure, to allow "small"
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* (run-time wise) functions to be executed at a specified frequency.
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* Things like LED blinking or watchdog triggering are examples for such
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* tasks.
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*
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* Copyright (C) 2022 Stefan Roese <sr@denx.de>
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*/
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#include <command.h>
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#include <cyclic.h>
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#include <div64.h>
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#include <malloc.h>
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#include <time.h>
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#include <vsprintf.h>
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#include <linux/delay.h>
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#include <linux/kernel.h>
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struct cyclic_demo_info {
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struct cyclic_info cyclic;
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uint delay_us;
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};
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static void cyclic_demo(struct cyclic_info *c)
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{
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struct cyclic_demo_info *info = container_of(c, struct cyclic_demo_info, cyclic);
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/* Just a small dummy delay here */
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udelay(info->delay_us);
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}
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static int do_cyclic_demo(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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struct cyclic_demo_info *info;
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uint time_ms;
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if (argc < 3)
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return CMD_RET_USAGE;
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info = malloc(sizeof(struct cyclic_demo_info));
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if (!info) {
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printf("out of memory\n");
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return CMD_RET_FAILURE;
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}
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time_ms = simple_strtoul(argv[1], NULL, 0);
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info->delay_us = simple_strtoul(argv[2], NULL, 0);
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/* Register demo cyclic function */
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cyclic_register(&info->cyclic, cyclic_demo, time_ms * 1000, "cyclic_demo");
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printf("Registered function \"%s\" to be executed all %dms\n",
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"cyclic_demo", time_ms);
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return 0;
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}
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static int do_cyclic_list(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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struct cyclic_info *cyclic;
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struct hlist_node *tmp;
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u64 cnt, freq;
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hlist_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list) {
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cnt = cyclic->run_cnt * 1000000ULL * 100ULL;
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freq = lldiv(cnt, timer_get_us() - cyclic->start_time_us);
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printf("function: %s, cpu-time: %lld us, frequency: %lld.%02d times/s\n",
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cyclic->name, cyclic->cpu_time_us,
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lldiv(freq, 100), do_div(freq, 100));
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}
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return 0;
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}
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U_BOOT_LONGHELP(cyclic,
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"demo <cycletime_ms> <delay_us> - register cyclic demo function\n"
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"cyclic list - list cyclic functions\n");
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U_BOOT_CMD_WITH_SUBCMDS(cyclic, "Cyclic", cyclic_help_text,
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U_BOOT_SUBCMD_MKENT(demo, 3, 1, do_cyclic_demo),
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U_BOOT_SUBCMD_MKENT(list, 1, 1, do_cyclic_list));
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