Replace deprecated qbus_reset_all by resettable_cold_reset_fn for
the sysbus reset registration.
Apart for the raspi machines, this does not impact the behavior
because:
+ at this point resettable just call the old reset methods of devices
and buses in the same order than qdev/qbus.
+ resettable handlers registered with qemu_register_reset are
serialized; there is no interleaving.
+ eventual explicit calls to legacy reset API (device_reset or
qdev/qbus_reset) inside this reset handler will not be masked out
by resettable mechanism; they do not go through resettable api.
For the raspi machines, during the sysbus reset the sd-card is not
reset twice anymore but only once. This is consequence of switching
both sysbus reset and changing parent to resettable; it detects the
second reset is not needed. This has no impact on the state after
reset; the sd-card reset method only reset local state and query
information from the block backend.
Signed-off-by: Damien Hedde <damien.he...@greensocs.com>
---
The raspi reset change can be observed by using the following command
(reset will occurs, then do Ctrl-C to end qemu; no firmware is
given here).
qemu-system-aarch64 -M raspi3 \
-trace resettable_phase_hold_exec \
-trace qdev_update_parent_bus \
-trace resettable_change_parent \
-trace qdev_reset -trace qbus_reset
Before the patch, the qdev/qbus_reset traces show when reset method are
called. After the patch, the resettable_phase_hold_exec show when reset
method are called.
The traced reset order of the raspi3 is listed below. I've added empty
lines and the tree structure.
+->bcm2835-peripherals reset
|
| +->sd-card reset
| +->sd-bus reset
+->bcm2835_gpio reset
| -> dev_update_parent_bus (move the sd-card on the sdhci-bus)
| -> resettable_change_parent
|
+->bcm2835-dma reset
|
| +->bcm2835-sdhost-bus reset
+->bcm2835-sdhost reset
|
| +->sd-card (reset ONLY BEFORE BEFORE THE PATCH)
| +->sdhci-bus reset
+->generic-sdhci reset
|
+->bcm2835-rng reset
+->bcm2835-property reset
+->bcm2835-fb reset
+->bcm2835-mbox reset
+->bcm2835-aux reset
+->pl011 reset
+->bcm2835-ic reset
+->bcm2836-control reset
System reset
In both case, the sd-card is reset (being on bcm2835_gpio/sd-bus) then moved
to generic-sdhci/sdhci-bus by the bcm2835_gpio reset method.
Before the patch, it is then reset again being part of generic-sdhci/sdhci-bus.
After the patch, it considered again for reset but its reset method is not
called because it is already flagged as reset.
---
vl.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/vl.c b/vl.c
index 4489cfb2bb..186f93e42f 100644
--- a/vl.c
+++ b/vl.c
@@ -4402,7 +4402,15 @@ int main(int argc, char **argv, char **envp)
/* TODO: once all bus devices are qdevified, this should be done
* when bus is created by qdev.c */
- qemu_register_reset(qbus_reset_all_fn, sysbus_get_default());
+ /*
+ * TODO: If we had a main 'reset container' that the whole system
+ * lived in, we could reset that using the multi-phase reset
+ * APIs. For the moment, we just reset the sysbus, which will cause
+ * all devices hanging off it (and all their child buses, recursively)
+ * to be reset. Note that this will *not* reset any Device objects
+ * which are not attached to some part of the qbus tree!
+ */
+ qemu_register_reset(resettable_cold_reset_fn, sysbus_get_default());
qemu_run_machine_init_done_notifiers();
if (rom_check_and_register_reset() != 0) {
--
2.23.0
