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[PULL 40/48] hw/misc/bcm2835_cprman: implement clock mux behaviour
From: |
Peter Maydell |
Subject: |
[PULL 40/48] hw/misc/bcm2835_cprman: implement clock mux behaviour |
Date: |
Tue, 27 Oct 2020 11:44:30 +0000 |
From: Luc Michel <luc@lmichel.fr>
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 <f4bug@amsat.org>
Signed-off-by: Luc Michel <luc@lmichel.fr>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
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 b22170f3bc2..919a55aa23f 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);
}
--
2.20.1
- [PULL 29/48] hw/arm/raspi: Add the Raspberry Pi 3 model A+, (continued)
- [PULL 29/48] hw/arm/raspi: Add the Raspberry Pi 3 model A+, Peter Maydell, 2020/10/27
- [PULL 32/48] hw/core/clock: trace clock values in Hz instead of ns, Peter Maydell, 2020/10/27
- [PULL 30/48] arm/trace: Fix hex printing, Peter Maydell, 2020/10/27
- [PULL 34/48] hw/arm/raspi: add a skeleton implementation of the CPRMAN, Peter Maydell, 2020/10/27
- [PULL 35/48] hw/misc/bcm2835_cprman: add a PLL skeleton implementation, Peter Maydell, 2020/10/27
- [PULL 36/48] hw/misc/bcm2835_cprman: implement PLLs behaviour, Peter Maydell, 2020/10/27
- [PULL 37/48] hw/misc/bcm2835_cprman: add a PLL channel skeleton implementation, Peter Maydell, 2020/10/27
- [PULL 38/48] hw/misc/bcm2835_cprman: implement PLL channels behaviour, Peter Maydell, 2020/10/27
- [PULL 39/48] hw/misc/bcm2835_cprman: add a clock mux skeleton implementation, Peter Maydell, 2020/10/27
- [PULL 42/48] hw/misc/bcm2835_cprman: add sane reset values to the registers, Peter Maydell, 2020/10/27
- [PULL 40/48] hw/misc/bcm2835_cprman: implement clock mux behaviour,
Peter Maydell <=
- [PULL 41/48] hw/misc/bcm2835_cprman: add the DSI0HSCK multiplexer, Peter Maydell, 2020/10/27
- [PULL 44/48] hw/arm/bcm2835_peripherals: connect the UART clock, Peter Maydell, 2020/10/27
- [PULL 43/48] hw/char/pl011: add a clock input, Peter Maydell, 2020/10/27
- [PULL 46/48] hw/arm/sbsa-ref: add SBSA watchdog device, Peter Maydell, 2020/10/27
- [PULL 45/48] hw/watchdog: Implement SBSA watchdog device, Peter Maydell, 2020/10/27
- [PULL 48/48] hw/timer/armv7m_systick: Rewrite to use ptimers, Peter Maydell, 2020/10/27
- [PULL 47/48] hw/core/ptimer: Support ptimer being disabled by timer callback, Peter Maydell, 2020/10/27
- Re: [PULL 00/48] target-arm queue, no-reply, 2020/10/27
- Re: [PULL 00/48] target-arm queue, Peter Maydell, 2020/10/29