On 06/11/2014 10:50 AM, Krzysztof Kozlowski wrote:
On pią, 2014-04-04 at 11:48 +0200, Daniel Lezcano wrote:
The following driver is for exynos4210. I did not yet finished the other boards, so
I created a specific driver for 4210 which could be merged later.
The driver is based on Colin Cross's driver found at:
https://android.googlesource.com/kernel/exynos/+/e686b1ec67423c40b4fdf811f9a4dfa3b393a010%5E%5E!/
This one was based on a 3.4 kernel and an old API.
It has been refreshed, simplified and based on the recent code cleanup I sent
today.
The AFTR could be entered when all the cpus (except cpu0) are down. In order to
reach this situation, the couple idle states are used.
There is a sync barrier at the entry and the exit of the low power function. So
all cpus will enter and exit the function at the same time.
At this point, CPU0 knows the other cpu will power down itself. CPU0 waits for
the CPU1 to be powered down and then initiate the AFTR power down sequence.
No interrupts are handled by CPU1, this is why we switch to the timer broadcast
even if the local timer is not impacted by the idle state.
When CPU0 wakes up, it powers up CPU1 and waits for it to boot. Then they both
exit the idle function.
This driver allows the exynos4210 to have the same power consumption at idle
time than the one when we have to unplug CPU1 in order to let CPU0 to reach
the AFTR state.
This patch is a RFC because, we have to find a way to remove the macros
definitions and cpu powerdown function without pulling the arch dependent
headers.
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
---
arch/arm/mach-exynos/common.c | 11 +-
drivers/cpuidle/Kconfig.arm | 8 ++
drivers/cpuidle/Makefile | 1 +
drivers/cpuidle/cpuidle-exynos4210.c | 226 ++++++++++++++++++++++++++++++++++
4 files changed, 245 insertions(+), 1 deletion(-)
create mode 100644 drivers/cpuidle/cpuidle-exynos4210.c
(...)
diff --git a/drivers/cpuidle/cpuidle-exynos4210.c b/drivers/cpuidle/cpuidle-exynos4210.c
new file mode 100644
index 0000000..56f6d51
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-exynos4210.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2014 Samsung Electronics Co., Ltd.
+ * http://www.samsung.com
+ *
+ * Copyright (c) 2014 Linaro : Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
+ * http://www.linaro.org
+ *
+ * Based on the work of Colin Cross <ccross@xxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/cpuidle.h>
+#include <linux/cpu_pm.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+
+#include <asm/proc-fns.h>
+#include <asm/suspend.h>
+#include <asm/cpuidle.h>
+
+#include <plat/pm.h>
+#include <plat/cpu.h>
+#include <plat/map-base.h>
+#include <plat/map-s5p.h>
+
+static atomic_t exynos_idle_barrier;
Hi,
Shouldn't the exynos_idle_barrier be initialized here?
As it is a static data it will be initialized to zero.
I know you sent the patch almost 2 months ago but I stomped on this
while testing it on Exynos3250.
No problem. And what results on exynos3250 ?
Thanks !
-- Daniel
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