powerpc: Convert power off logic to pm_power_off

The generic Linux framework to power off the machine is a function pointer
called pm_power_off. The trick about this pointer is that device drivers can
potentially implement it rather than board files.

Today on powerpc we set pm_power_off to invoke our generic full machine power
off logic which then calls ppc_md.power_off to invoke machine specific power
off.

However, when we want to add a power off GPIO via the "gpio-poweroff" driver,
this card house falls apart. That driver only registers itself if pm_power_off
is NULL to ensure it doesn't override board specific logic. However, since we
always set pm_power_off to the generic power off logic (which will just not
power off the machine if no ppc_md.power_off call is implemented), we can't
implement power off via the generic GPIO power off driver.

To fix this up, let's get rid of the ppc_md.power_off logic and just always use
pm_power_off as was intended. Then individual drivers such as the GPIO power off
driver can implement power off logic via that function pointer.

With this patch set applied and a few patches on top of QEMU that implement a
power off GPIO on the virt e500 machine, I can successfully turn off my virtual
machine after halt.

Signed-off-by: Alexander Graf <agraf@suse.de>
[mpe: Squash into one patch and update changelog based on cover letter]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

3 files changed, 7 insertions, 3 deletions

diff --git a/arch/powerpc/platforms/embedded6xx/gamecube.c b/arch/powerpc/platforms/embedded6xx/gamecube.c
index bd4ba5d7d568..fe0ed6ee285e 100644
--- a/arch/powerpc/platforms/embedded6xx/gamecube.c
+++ b/arch/powerpc/platforms/embedded6xx/gamecube.c
@@ -67,6 +67,8 @@ static int __init gamecube_probe(void)
 	if (!of_flat_dt_is_compatible(dt_root, "nintendo,gamecube"))
 		return 0;
 
+	pm_power_off = gamecube_power_off;
+
 	return 1;
 }
 
@@ -80,7 +82,6 @@ define_machine(gamecube) {
 	.probe			= gamecube_probe,
 	.init_early		= gamecube_init_early,
 	.restart		= gamecube_restart,
-	.power_off		= gamecube_power_off,
 	.halt			= gamecube_halt,
 	.init_IRQ		= flipper_pic_probe,
 	.get_irq		= flipper_pic_get_irq,
diff --git a/arch/powerpc/platforms/embedded6xx/linkstation.c b/arch/powerpc/platforms/embedded6xx/linkstation.c
index 168e1d80b2e5..540eeb58d3f0 100644
--- a/arch/powerpc/platforms/embedded6xx/linkstation.c
+++ b/arch/powerpc/platforms/embedded6xx/linkstation.c
@@ -147,6 +147,9 @@ static int __init linkstation_probe(void)
 
 	if (!of_flat_dt_is_compatible(root, "linkstation"))
 		return 0;
+
+	pm_power_off = linkstation_power_off;
+
 	return 1;
 }
 
@@ -158,7 +161,6 @@ define_machine(linkstation){
 	.show_cpuinfo 		= linkstation_show_cpuinfo,
 	.get_irq 		= mpic_get_irq,
 	.restart 		= linkstation_restart,
-	.power_off 		= linkstation_power_off,
 	.halt	 		= linkstation_halt,
 	.calibrate_decr 	= generic_calibrate_decr,
 };
diff --git a/arch/powerpc/platforms/embedded6xx/wii.c b/arch/powerpc/platforms/embedded6xx/wii.c
index 388e29bab8f6..352592d3e44e 100644
--- a/arch/powerpc/platforms/embedded6xx/wii.c
+++ b/arch/powerpc/platforms/embedded6xx/wii.c
@@ -211,6 +211,8 @@ static int __init wii_probe(void)
 	if (!of_flat_dt_is_compatible(dt_root, "nintendo,wii"))
 		return 0;
 
+	pm_power_off = wii_power_off;
+
 	return 1;
 }
 
@@ -226,7 +228,6 @@ define_machine(wii) {
 	.init_early		= wii_init_early,
 	.setup_arch		= wii_setup_arch,
 	.restart		= wii_restart,
-	.power_off		= wii_power_off,
 	.halt			= wii_halt,
 	.init_IRQ		= wii_pic_probe,
 	.get_irq		= flipper_pic_get_irq,