diff options
Diffstat (limited to 'hw/core')
| -rw-r--r-- | hw/core/ptimer.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c index 2aa97cb665..6ba19fd965 100644 --- a/hw/core/ptimer.c +++ b/hw/core/ptimer.c @@ -15,6 +15,7 @@ #include "sysemu/qtest.h" #include "block/aio.h" #include "sysemu/cpus.h" +#include "hw/clock.h" #define DELTA_ADJUST 1 #define DELTA_NO_ADJUST -1 @@ -348,6 +349,39 @@ void ptimer_set_period(ptimer_state *s, int64_t period) } } +/* Set counter increment interval from a Clock */ +void ptimer_set_period_from_clock(ptimer_state *s, const Clock *clk, + unsigned int divisor) +{ + /* + * The raw clock period is a 64-bit value in units of 2^-32 ns; + * put another way it's a 32.32 fixed-point ns value. Our internal + * representation of the period is 64.32 fixed point ns, so + * the conversion is simple. + */ + uint64_t raw_period = clock_get(clk); + uint64_t period_frac; + + assert(s->in_transaction); + s->delta = ptimer_get_count(s); + s->period = extract64(raw_period, 32, 32); + period_frac = extract64(raw_period, 0, 32); + /* + * divisor specifies a possible frequency divisor between the + * clock and the timer, so it is a multiplier on the period. + * We do the multiply after splitting the raw period out into + * period and frac to avoid having to do a 32*64->96 multiply. + */ + s->period *= divisor; + period_frac *= divisor; + s->period += extract64(period_frac, 32, 32); + s->period_frac = (uint32_t)period_frac; + + if (s->enabled) { + s->need_reload = true; + } +} + /* Set counter frequency in Hz. */ void ptimer_set_freq(ptimer_state *s, uint32_t freq) { |