Re: [PATCH v2 6/6] ARM: tegra: cpuidle: use firmware for power down

From: Alexandre Courbot
Date: Tue Feb 11 2014 - 20:56:31 EST


On 02/12/2014 10:36 AM, Olof Johansson wrote:
On Fri, Feb 07, 2014 at 01:35:06PM +0900, Alexandre Courbot wrote:
Attempt to invoke the prepare_idle() and do_idle() firmware calls
to power down a CPU so an underlying firmware gets informed of
the idle operation and performs it by itself if designed in such a way.

Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
---
arch/arm/mach-tegra/cpuidle-tegra114.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-tegra/cpuidle-tegra114.c b/arch/arm/mach-tegra/cpuidle-tegra114.c
index e0b87300243d..558067ddc186 100644
--- a/arch/arm/mach-tegra/cpuidle-tegra114.c
+++ b/arch/arm/mach-tegra/cpuidle-tegra114.c
@@ -19,6 +19,7 @@
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/clockchips.h>
+#include <asm/firmware.h>

#include <asm/cpuidle.h>
#include <asm/suspend.h>
@@ -45,7 +46,15 @@ static int tegra114_idle_power_down(struct cpuidle_device *dev,

clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu);

- cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
+ call_firmware_op(prepare_idle);
+
+ switch (call_firmware_op(do_idle)) {
+ case -ENOSYS:
+ cpu_suspend(0, tegra30_sleep_cpu_secondary_finish);
+ break;
+ default:
+ break;

Do you expect other cases down the road? If not, this is a simple if instead:

/* Only call cpu_suspend if TF didn't handle the pre-suspend logic */
if (call_firmware_op(do_idle) == -ENOSYS)
cpu_suspend(....);

I might have been overdoing it indeed. Let me submit a v3 just for this one patch.

Thanks!
Alex.

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