include/hw/ptimer.h

15  * The countdown timer has a value (which can be read and written via
17  * using ptimer_run(), the value will count downwards at the frequency
20  * can be set to either reload itself from a specified limit value
21  * and keep counting down, or to stop (as a one-shot timer).
23  * A transaction-based API is used for modifying ptimer state: all calls
29  * list of state-modifying functions and detailed semantics of the callback.)
49  *  - Starting to run with a period = 0 emits error message and stops the
52  *  - Setting period to 0 of the running timer emits error message and
55  *  - Starting to run with counter = 0 or setting it to "0" while timer
56  *    is running causes a trigger and reloads counter with a limit value.
59  *  - Counter value of the running timer is one less than the actual value.
61  *  - Changing period/frequency of the running timer loses time elapsed
63  *    counter = counter value at the moment of change (.i.e. one less).
72  * re-trigger every period.  */
79 /* Starting to run with/setting counter to "0" won't re-load counter
83 /* Make counter value of the running timer represent the actual value and
101  * ptimer_init - Allocate and return a new ptimer
109  * transaction-based API for modifying ptimer state: all calls
111  *  - ptimer_set_period()
112  *  - ptimer_set_freq()
113  *  - ptimer_set_limit()
114  *  - ptimer_set_count()
115  *  - ptimer_run()
116  *  - ptimer_stop()
133  * ptimer_free - Free a ptimer
141  * ptimer_transaction_begin() - Start a ptimer modification transaction
147  * It is an error to call this function for a BH-based ptimer;
153  * ptimer_transaction_commit() - Commit a ptimer modification transaction
163  * ptimer_set_period - Set counter increment interval in nanoseconds
177  * ptimer_set_period_from_clock - Set counter increment from a Clock
180  * @divisor: value to scale the clock frequency down by
199  * ptimer_set_freq - Set counter frequency in Hz
215  * ptimer_get_limit - Get the configured limit of the ptimer
218  * This function returns the current limit (reload) value
219  * of the down-counter; that is, the value which it will be
230  * ptimer_set_limit - Set the limit of the ptimer
232  * @limit: initial countdown value
235  * Set the limit value of the down-counter. The @reload flag can
245  * ptimer_get_count - Get the current value of the ptimer
248  * Return the current value of the down-counter. This will
249  * return the correct value whether the counter is enabled or
255  * ptimer_set_count - Set the current value of the ptimer
257  * @count: count value to set
259  * Set the value of the down-counter. If the counter is currently
269  * ptimer_run - Start a ptimer counting
271  * @oneshot: non-zero if this timer should only count down once
273  * Start a ptimer counting down; when it reaches zero the callback function
276  * the counter value will then be reloaded from the limit and it will
277  * start counting down again. If @oneshot is non-zero, then the counter
286  * ptimer_stop - Stop a ptimer counting
289  * Pause a timer (the count stays at its current value until ptimer_run()
290  * is called to start it counting again).