hw/misc/bcm2835_cprman: add sane reset values to the registers

Those reset values have been extracted from a Raspberry Pi 3 model B
v1.2, using the 2020-08-20 version of raspios. The dump was done using
the debugfs interface of the CPRMAN driver in Linux (under
'/sys/kernel/debug/clk'). Each exposed clock tree stage (PLLs, channels
and muxes) can be observed by reading the 'regdump' file (e.g.
'plla/regdump').

Those values are set by the Raspberry Pi firmware at boot time (Linux
expects them to be set when it boots up).

Some stages are not exposed by the Linux driver (e.g. the PLL B). For
those, the reset values are unknown and left to 0 which implies a
disabled output.

Once booted in QEMU, the final clock tree is very similar to the one
visible on real hardware. The differences come from some unimplemented
devices for which the driver simply disable the corresponding clock.

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>

1 files changed, 31 insertions, 0 deletions

diff --git a/hw/misc/bcm2835_cprman.c b/hw/misc/bcm2835_cprman.c
index 7a74019..7e415a0 100644
--- a/hw/misc/bcm2835_cprman.c
+++ b/hw/misc/bcm2835_cprman.c
@@ -53,6 +53,17 @@
 
 /* PLL */
 
+static void pll_reset(DeviceState *dev)
+{
+    CprmanPllState *s = CPRMAN_PLL(dev);
+    const PLLResetInfo *info = &PLL_RESET_INFO[s->id];
+
+    *s->reg_cm = info->cm;
+    *s->reg_a2w_ctrl = info->a2w_ctrl;
+    memcpy(s->reg_a2w_ana, info->a2w_ana, sizeof(info->a2w_ana));
+    *s->reg_a2w_frac = info->a2w_frac;
+}
+
 static bool pll_is_locked(const CprmanPllState *pll)
 {
     return !FIELD_EX32(*pll->reg_a2w_ctrl, A2W_PLLx_CTRL, PWRDN)
@@ -123,6 +134,7 @@ static void pll_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
+    dc->reset = pll_reset;
     dc->vmsd = &pll_vmstate;
 }
 
@@ -137,6 +149,14 @@ static const TypeInfo cprman_pll_info = {
 
 /* PLL channel */
 
+static void pll_channel_reset(DeviceState *dev)
+{
+    CprmanPllChannelState *s = CPRMAN_PLL_CHANNEL(dev);
+    const PLLChannelResetInfo *info = &PLL_CHANNEL_RESET_INFO[s->id];
+
+    *s->reg_a2w_ctrl = info->a2w_ctrl;
+}
+
 static bool pll_channel_is_enabled(CprmanPllChannelState *channel)
 {
     /*
@@ -217,6 +237,7 @@ static void pll_channel_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
+    dc->reset = pll_channel_reset;
     dc->vmsd = &pll_channel_vmstate;
 }
 
@@ -295,6 +316,15 @@ static void clock_mux_src_update(void *opaque)
     clock_mux_update(s);
 }
 
+static void clock_mux_reset(DeviceState *dev)
+{
+    CprmanClockMuxState *clock = CPRMAN_CLOCK_MUX(dev);
+    const ClockMuxResetInfo *info = &CLOCK_MUX_RESET_INFO[clock->id];
+
+    *clock->reg_ctl = info->cm_ctl;
+    *clock->reg_div = info->cm_div;
+}
+
 static void clock_mux_init(Object *obj)
 {
     CprmanClockMuxState *s = CPRMAN_CLOCK_MUX(obj);
@@ -327,6 +357,7 @@ static void clock_mux_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
+    dc->reset = clock_mux_reset;
     dc->vmsd = &clock_mux_vmstate;
 }