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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>
128 lines
3.2 KiB
C
128 lines
3.2 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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#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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* @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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* When !CONFIG_CYCLIC, this struct is empty.
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*/
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struct cyclic_info {
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#if defined(CONFIG_CYCLIC)
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void (*func)(struct cyclic_info *c);
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const 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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#endif
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};
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/** Function type for cyclic functions */
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typedef void (*cyclic_func_t)(struct cyclic_info *c);
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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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* @cyclic: Cyclic info structure
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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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*
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* The function @func will be called with @cyclic as its
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* argument. @cyclic will usually be embedded in some device-specific
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* structure, which the callback can retrieve using container_of().
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*/
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void cyclic_register(struct cyclic_info *cyclic, cyclic_func_t func,
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uint64_t delay_us, const char *name);
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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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*/
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void 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 void cyclic_register(struct cyclic_info *cyclic, cyclic_func_t func,
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uint64_t delay_us, const char *name)
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{
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}
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static inline void cyclic_unregister(struct cyclic_info *cyclic)
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{
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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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