src/include/thread.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 #ifndef THREAD_H_
   3 #define THREAD_H_
   4
   5 #include <arch/cpu.h>
   6 #include <bootstate.h>
   7 #include <types.h>
   8
   9 struct thread_mutex {
  10         bool locked;
  11 };
  12
  13 enum thread_state {
  14         THREAD_UNINITIALIZED,
  15         THREAD_STARTED,
  16         THREAD_DONE,
  17 };
  18
  19 struct thread_handle {
  20         enum thread_state state;
  21         /* Only valid when state == THREAD_DONE */
  22         enum cb_err error;
  23 };
  24
  25 /* Run func(arg) on a new thread. Return 0 on successful start of thread, < 0
  26  * when thread could not be started. The thread handle if populated, will
  27  * reflect the state and return code of the thread.
  28  */
  29 int thread_run(struct thread_handle *handle, enum cb_err (*func)(void *), void *arg);
  30
  31 /* thread_run_until is the same as thread_run() except that it blocks state
  32  * transitions from occurring in the (state, seq) pair of the boot state
  33  * machine. */
  34 int thread_run_until(struct thread_handle *handle, enum cb_err (*func)(void *), void *arg,
  35                      boot_state_t state, boot_state_sequence_t seq);
  36
  37 /* Waits until the thread has terminated and returns the error code */
  38 enum cb_err thread_join(struct thread_handle *handle);
  39
  40 #if ENV_SUPPORTS_COOP
  41
  42 struct thread {
  43         int id;
  44         uintptr_t stack_current;
  45         uintptr_t stack_orig;
  46         struct thread *next;
  47         enum cb_err (*entry)(void *);
  48         void *entry_arg;
  49         int can_yield;
  50         struct thread_handle *handle;
  51 };
  52
  53 /* Return 0 on successful yield, < 0 when thread did not yield. */
  54 int thread_yield(void);
  55
  56 /* Return 0 on successful yield for the given amount of time, < 0 when thread
  57  * did not yield. */
  58 int thread_yield_microseconds(unsigned int microsecs);
  59
  60 /* Allow and prevent thread cooperation on current running thread. By default
  61  * all threads are marked to be cooperative. That means a thread can yield
  62  * to another thread at a pre-determined switch point. i.e., udelay,
  63  * thread_yield, or thread_yield_microseconds.
  64  *
  65  * These methods should be used to guard critical sections so a dead lock does
  66  * not occur. The critical sections can be nested. Just make sure the methods
  67  * are used in pairs.
  68  */
  69 void thread_coop_enable(void);
  70 void thread_coop_disable(void);
  71
  72 void thread_mutex_lock(struct thread_mutex *mutex);
  73 void thread_mutex_unlock(struct thread_mutex *mutex);
  74
  75 /* Architecture specific thread functions. */
  76 asmlinkage void switch_to_thread(uintptr_t new_stack, uintptr_t *saved_stack);
  77 /* Set up the stack frame for a new thread so that a switch_to_thread() call
  78  * will enter the thread_entry() function with arg as a parameter. The
  79  * saved_stack field in the struct thread needs to be updated accordingly. */
  80 void arch_prepare_thread(struct thread *t,
  81                          asmlinkage void (*thread_entry)(void *), void *arg);
  82 #else
  83 static inline int thread_yield(void)
  84 {
  85         return -1;
  86 }
  87 static inline int thread_yield_microseconds(unsigned int microsecs)
  88 {
  89         return -1;
  90 }
  91 static inline void thread_coop_enable(void) {}
  92 static inline void thread_coop_disable(void) {}
  93
  94 static inline void thread_mutex_lock(struct thread_mutex *mutex) {}
  95
  96 static inline void thread_mutex_unlock(struct thread_mutex *mutex) {}
  97 #endif
  98
  99 #endif /* THREAD_H_ */