On 10/10/20 3:57 PM, Luc Michel wrote:
A clock mux can be configured to select one of its 10 sources through
the CM_CTL register. It also embeds yet another clock divider, composed
of an integer part and a fractional part. The number of bits of each
part is mux dependent.
Tested-by: Philippe Mathieu-Daudé <f4...@amsat.org>
Signed-off-by: Luc Michel <l...@lmichel.fr>
---
hw/misc/bcm2835_cprman.c | 53 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 52 insertions(+), 1 deletion(-)
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
@@ -229,19 +229,70 @@ 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);
}
Much nicer now, thanks :)
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
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);
}
static void clock_mux_init(Object *obj)
