diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/hw/clock.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/include/hw/clock.h b/include/hw/clock.h index a7187ea..11f67fb 100644 --- a/include/hw/clock.h +++ b/include/hw/clock.h @@ -81,6 +81,10 @@ struct Clock { void *callback_opaque; unsigned int callback_events; + /* Ratio of the parent clock to run the child clocks at */ + uint32_t multiplier; + uint32_t divider; + /* Clocks are organized in a clock tree */ Clock *source; QLIST_HEAD(, Clock) children; @@ -350,4 +354,29 @@ static inline bool clock_is_enabled(const Clock *clk) */ char *clock_display_freq(Clock *clk); +/** + * clock_set_mul_div: set multiplier/divider for child clocks + * @clk: clock + * @multiplier: multiplier value + * @divider: divider value + * + * By default, a Clock's children will all run with the same period + * as their parent. This function allows you to adjust the multiplier + * and divider used to derive the child clock frequency. + * For example, setting a multiplier of 2 and a divider of 3 + * will run child clocks with a period 2/3 of the parent clock, + * so if the parent clock is an 8MHz clock the children will + * be 12MHz. + * + * Setting the multiplier to 0 will stop the child clocks. + * Setting the divider to 0 is a programming error (diagnosed with + * an assertion failure). + * Setting a multiplier value that results in the child period + * overflowing is not diagnosed. + * + * Note that this function does not call clock_propagate(); the + * caller should do that if necessary. + */ +void clock_set_mul_div(Clock *clk, uint32_t multiplier, uint32_t divider); + #endif /* QEMU_HW_CLOCK_H */ |