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[PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour
From: |
Luc Michel |
Subject: |
[PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour |
Date: |
Fri, 25 Sep 2020 12:17:27 +0200 |
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 fractionnal part. The number of bits of each
part is mux dependant.
Signed-off-by: Luc Michel <luc@lmichel.fr>
---
hw/misc/bcm2835_cprman.c | 43 +++++++++++++++++++++++++++++++++++++++-
1 file changed, 42 insertions(+), 1 deletion(-)
diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c
index 8df2db0fd9..75bc11939b 100644
--- a/hw/misc/bcm2835_cprman.c
+++ b/hw/misc/bcm2835_cprman.c
@@ -229,19 +229,60 @@ static const TypeInfo cprman_pll_channel_info = {
};
/* clock mux */
+static bool clock_mux_is_enabled(CprmanClockMuxState *mux)
+{
+ return FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, ENABLE);
+}
+
static void clock_mux_update(CprmanClockMuxState *mux)
{
- clock_update(mux->out, 0);
+ uint64_t freq, div;
+ uint32_t src = FIELD_EX32(*mux->reg_cm, CM_CLOCKx_CTL, SRC);
+ bool enabled = clock_mux_is_enabled(mux);
+
+ *mux->reg_cm = FIELD_DP32(*mux->reg_cm, 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.
+ */
+ div = mux->reg_cm[1] >> (R_CM_CLOCKx_DIV_FRAC_LENGTH - mux->frac_bits);
+ div &= (1 << (mux->int_bits + mux->frac_bits)) - 1;
+
+ freq = (freq << 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;
+ uint32_t current_src;
+
+ current_src = FIELD_EX32(*s->reg_cm, CM_CLOCKx_CTL, SRC);
+
+ if (current_src != src) {
+ return;
+ }
clock_mux_update(s);
}
static void clock_mux_init(Object *obj)
--
2.28.0
- Re: [PATCH 01/14] hw/core/clock: provide the VMSTATE_ARRAY_CLOCK macro, (continued)
- [PATCH 04/14] hw/arm/raspi: add a skeleton implementation of the cprman, Luc Michel, 2020/09/25
- [PATCH 06/14] hw/misc/bcm2835_cprman: implement PLLs behaviour, Luc Michel, 2020/09/25
- [PATCH 02/14] hw/core/clock: trace clock values in Hz instead of ns, Luc Michel, 2020/09/25
- [PATCH 11/14] hw/misc/bcm2835_cprman: add the DSI0HSCK multiplexer, Luc Michel, 2020/09/25
- [PATCH 08/14] hw/misc/bcm2835_cprman: implement PLL channels behaviour, Luc Michel, 2020/09/25
- [PATCH 10/14] hw/misc/bcm2835_cprman: implement clock mux behaviour,
Luc Michel <=
- [PATCH 07/14] hw/misc/bcm2835_cprman: add a PLL channel skeleton implementation, Luc Michel, 2020/09/25
- [PATCH 05/14] hw/misc/bcm2835_cprman: add a PLL skeleton implementation, Luc Michel, 2020/09/25
- [PATCH 03/14] hw/arm/raspi: fix cprman base address, Luc Michel, 2020/09/25
- [PATCH 12/14] hw/misc/bcm2835_cprman: add sane reset values to the registers, Luc Michel, 2020/09/25
- [RFC PATCH 13/14] hw/char/pl011: add a clock input, Luc Michel, 2020/09/25