qemu/hw/openrisc
Stafford Horne f4d1414a93 target/openrisc: Support non-busy idle state using PMR SPR
The OpenRISC architecture has the Power Management Register (PMR)
special purpose register to manage cpu power states.  The interesting
modes are:

 * Doze Mode (DME) - Stop cpu except timer & pic - wake on interrupt
 * Sleep Mode (SME) - Stop cpu and all units - wake on interrupt
 * Suspend Model (SUME) - Stop cpu and all units - wake on reset

The linux kernel will set DME when idle.

This patch implements the PMR SPR and halts the qemu cpu when there is a
change to DME or SME.  This means that openrisc qemu in no longer peggs
a host cpu at 100%.

In order for this to work we need to kick the CPU when timers are
expired.  Update the cpu timer to kick the cpu upon each timer event.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Stafford Horne <shorne@gmail.com>
2017-05-04 09:39:14 +09:00
..
cputimer.c target/openrisc: Support non-busy idle state using PMR SPR 2017-05-04 09:39:14 +09:00
Makefile.objs hw: move boards and other isolated files to hw/ARCH 2013-03-01 15:01:19 +01:00
openrisc_sim.c target/openrisc: Rename the cpu from or32 to or1k 2017-02-14 08:14:58 +11:00
pic_cpu.c openrisc: Clean up includes 2016-01-29 15:07:24 +00:00