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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-*
128 lines
3.1 KiB
C
128 lines
3.1 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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#ifndef __cyclic_h
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#define __cyclic_h
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#include <linux/list.h>
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#include <asm/types.h>
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/**
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* struct cyclic_info - Information about cyclic execution function
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*
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* @func: Function to call periodically
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* @ctx: Context pointer to get passed to this function
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* @name: Name of the cyclic function, e.g. shown in the commands
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* @delay_ns: Delay is ns after which this function shall get executed
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* @start_time_us: Start time in us, when this function started its execution
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* @cpu_time_us: Total CPU time of this function
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* @run_cnt: Counter of executions occurances
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* @next_call: Next time in us, when the function shall be executed again
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* @list: List node
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* @already_warned: Flag that we've warned about exceeding CPU time usage
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*/
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struct cyclic_info {
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void (*func)(void *ctx);
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void *ctx;
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char *name;
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uint64_t delay_us;
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uint64_t start_time_us;
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uint64_t cpu_time_us;
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uint64_t run_cnt;
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uint64_t next_call;
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struct hlist_node list;
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bool already_warned;
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};
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/** Function type for cyclic functions */
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typedef void (*cyclic_func_t)(void *ctx);
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#if defined(CONFIG_CYCLIC)
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/**
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* cyclic_register - Register a new cyclic function
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*
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* @func: Function to call periodically
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* @delay_us: Delay is us after which this function shall get executed
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* @name: Cyclic function name/id
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* @ctx: Context to pass to the function
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* @return: pointer to cyclic_struct if OK, NULL on error
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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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* cyclic_unregister - Unregister a cyclic function
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*
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* @cyclic: Pointer to cyclic_struct of the function that shall be removed
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* @return: 0 if OK, -ve on error
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*/
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int cyclic_unregister(struct cyclic_info *cyclic);
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/**
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* cyclic_unregister_all() - Clean up cyclic functions
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*
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* This removes all cyclic functions
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*/
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int cyclic_unregister_all(void);
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/**
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* cyclic_get_list() - Get cyclic list pointer
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*
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* Return the cyclic list pointer
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*
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* @return: pointer to cyclic_list
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*/
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struct hlist_head *cyclic_get_list(void);
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/**
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* cyclic_run() - Interate over all registered cyclic functions
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*
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* Interate over all registered cyclic functions and if the it's function
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* needs to be executed, then call into these registered functions.
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*/
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void cyclic_run(void);
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/**
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* schedule() - Schedule all potentially waiting tasks
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*
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* Basically a wrapper for cyclic_run(), pontentially enhanced by some
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* other parts, that need to get handled periodically.
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*/
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void schedule(void);
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#else
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static inline struct cyclic_info *cyclic_register(cyclic_func_t func,
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uint64_t delay_us,
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const char *name,
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void *ctx)
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{
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return NULL;
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}
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static inline int cyclic_unregister(struct cyclic_info *cyclic)
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{
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return 0;
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}
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static inline void cyclic_run(void)
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{
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}
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static inline void schedule(void)
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{
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}
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static inline int cyclic_unregister_all(void)
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{
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return 0;
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}
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#endif
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#endif
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