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50128aeb0f
Currently, we must call cyclic_init() at some point before cyclic_register() becomes possible. That turns out to be somewhat awkward, especially with SPL, and has resulted in a watchdog callback not being registered, thus causing the board to prematurely reset. We already rely on gd->cyclic reliably being set to NULL by the asm code that clears all of gd. Now that the cyclic list is a hlist, and thus an empty list is represented by a NULL head pointer, and struct cyclic_drv has no other members, we can just as well drop a level of indirection and put the hlist_head directly in struct global_data. This doesn't increase the size of struct global_data, gets rid of an early malloc(), and generates slightly smaller code. But primarily, this avoids having to call cyclic_init() early; the cyclic infrastructure is simply ready to register callbacks as soon as we enter C code. We can still end up with schedule() being called from asm very early, so we still need to check that gd itself has been properly initialized [*], but once it has, gd->cyclic_list is perfectly fine to access, and will just be an empty list. As for cyclic_uninit(), it was never really the opposite of cyclic_init() since it didn't free the struct cyclic_drv nor set gd->cyclic to NULL. Rename it to cyclic_unregister_all() and use that in test/, and also insert a call at the end of the board_init_f sequence so that gd->cyclic_list is a fresh empty list before we enter board_init_r(). A small piece of ugliness is that I had to add a cast in cyclic_get_list() to silence a "discards 'volatile' qualifier" warning, but that is completely equivalent to the existing handling of the uclass_root_s list_head member. [*] I'm not really sure where we guarantee that the register used for gd contains 0 until it gets explicitly initialized, but that must be the case, otherwise testing gd for being NULL would not make much sense. Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk> Reviewed-by: Stefan Roese <sr@denx.de> Tested-by: Stefan Roese <sr@denx.de> Tested-by: Tim Harvey <tharvey@gateworks.com> # imx8mm-venice-*
125 lines
2.9 KiB
C
125 lines
2.9 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 <cyclic.h>
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#include <log.h>
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#include <malloc.h>
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#include <time.h>
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#include <linux/errno.h>
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#include <linux/list.h>
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#include <asm/global_data.h>
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DECLARE_GLOBAL_DATA_PTR;
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void hw_watchdog_reset(void);
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struct hlist_head *cyclic_get_list(void)
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{
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/* Silence "discards 'volatile' qualifier" warning. */
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return (struct hlist_head *)&gd->cyclic_list;
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}
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struct cyclic_info *cyclic_register(cyclic_func_t func, uint64_t delay_us,
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const char *name, void *ctx)
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{
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struct cyclic_info *cyclic;
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cyclic = calloc(1, sizeof(struct cyclic_info));
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if (!cyclic) {
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pr_debug("Memory allocation error\n");
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return NULL;
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}
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/* Store values in struct */
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cyclic->func = func;
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cyclic->ctx = ctx;
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cyclic->name = strdup(name);
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cyclic->delay_us = delay_us;
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cyclic->start_time_us = timer_get_us();
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hlist_add_head(&cyclic->list, cyclic_get_list());
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return cyclic;
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}
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int cyclic_unregister(struct cyclic_info *cyclic)
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{
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hlist_del(&cyclic->list);
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free(cyclic);
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return 0;
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}
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void cyclic_run(void)
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{
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struct cyclic_info *cyclic;
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struct hlist_node *tmp;
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uint64_t now, cpu_time;
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/* Prevent recursion */
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if (gd->flags & GD_FLG_CYCLIC_RUNNING)
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return;
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gd->flags |= GD_FLG_CYCLIC_RUNNING;
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hlist_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list) {
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/*
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* Check if this cyclic function needs to get called, e.g.
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* do not call the cyclic func too often
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*/
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now = timer_get_us();
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if (time_after_eq64(now, cyclic->next_call)) {
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/* Call cyclic function and account it's cpu-time */
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cyclic->next_call = now + cyclic->delay_us;
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cyclic->func(cyclic->ctx);
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cyclic->run_cnt++;
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cpu_time = timer_get_us() - now;
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cyclic->cpu_time_us += cpu_time;
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/* Check if cpu-time exceeds max allowed time */
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if ((cpu_time > CONFIG_CYCLIC_MAX_CPU_TIME_US) &&
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(!cyclic->already_warned)) {
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pr_err("cyclic function %s took too long: %lldus vs %dus max\n",
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cyclic->name, cpu_time,
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CONFIG_CYCLIC_MAX_CPU_TIME_US);
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/*
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* Don't disable this function, just warn once
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* about this exceeding CPU time usage
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*/
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cyclic->already_warned = true;
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}
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}
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}
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gd->flags &= ~GD_FLG_CYCLIC_RUNNING;
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}
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void schedule(void)
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{
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/* The HW watchdog is not integrated into the cyclic IF (yet) */
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if (IS_ENABLED(CONFIG_HW_WATCHDOG))
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hw_watchdog_reset();
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/*
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* schedule() might get called very early before the cyclic IF is
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* ready. Make sure to only call cyclic_run() when it's initalized.
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*/
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if (gd)
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cyclic_run();
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}
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int cyclic_unregister_all(void)
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{
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struct cyclic_info *cyclic;
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struct hlist_node *tmp;
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hlist_for_each_entry_safe(cyclic, tmp, cyclic_get_list(), list)
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cyclic_unregister(cyclic);
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return 0;
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}
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