diff options
| -rw-r--r-- | hw/misc/bcm2835_cprman.c | 53 |
1 files changed, 52 insertions, 1 deletions
diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c index b22170f3bc..919a55aa23 100644 --- a/hw/misc/bcm2835_cprman.c +++ b/hw/misc/bcm2835_cprman.c @@ -231,15 +231,66 @@ static const TypeInfo cprman_pll_channel_info = { /* clock mux */ +static bool clock_mux_is_enabled(CprmanClockMuxState *mux) +{ + return FIELD_EX32(*mux->reg_ctl, CM_CLOCKx_CTL, ENABLE); +} + static void clock_mux_update(CprmanClockMuxState *mux) { - clock_update(mux->out, 0); + uint64_t freq; + uint32_t div, src = FIELD_EX32(*mux->reg_ctl, CM_CLOCKx_CTL, SRC); + bool enabled = clock_mux_is_enabled(mux); + + *mux->reg_ctl = FIELD_DP32(*mux->reg_ctl, CM_CLOCKx_CTL, BUSY, enabled); + + if (!enabled) { + clock_update(mux->out, 0); + return; + } + + freq = clock_get_hz(mux->srcs[src]); + + if (mux->int_bits == 0 && mux->frac_bits == 0) { + clock_update_hz(mux->out, freq); + return; + } + + /* + * The divider has an integer and a fractional part. The size of each part + * varies with the muxes (int_bits and frac_bits). Both parts are + * concatenated, with the integer part always starting at bit 12. + * + * 31 12 11 0 + * ------------------------------ + * CM_DIV | | int | frac | | + * ------------------------------ + * <-----> <------> + * int_bits frac_bits + */ + div = extract32(*mux->reg_div, + R_CM_CLOCKx_DIV_FRAC_LENGTH - mux->frac_bits, + mux->int_bits + mux->frac_bits); + + if (!div) { + clock_update(mux->out, 0); + return; + } + + freq = muldiv64(freq, 1 << mux->frac_bits, div); + + clock_update_hz(mux->out, freq); } static void clock_mux_src_update(void *opaque) { CprmanClockMuxState **backref = opaque; CprmanClockMuxState *s = *backref; + CprmanClockMuxSource src = backref - s->backref; + + if (FIELD_EX32(*s->reg_ctl, CM_CLOCKx_CTL, SRC) != src) { + return; + } clock_mux_update(s); } |