On Thu, 2016-09-29 at 10:21 +0000, C.H. Zhao wrote:

From: Scott Wood <oss@buserror.net>
Sent: Thursday, September 29, 2016 4:03 AM
To: C.H. Zhao
Cc: linuxppc-dev@lists.ozlabs.org; linux-kernel@vger.kernel.org; z.chenhui@g
mail.com; Jason Jin
Subject: Re: [v3,4/5] powerpc/pm: support deep sleep feature on T104x
    
On Tue, 2016-09-27 at 11:05 +0000, C.H. Zhao wrote:

quoted

From: Scott Wood <oss@buserror.net>
Sent: Sunday, September 25, 2016 3:24 PM
To: C.H. Zhao
Cc: linuxppc-dev@lists.ozlabs.org; linux-kernel@vger.kernel.org; z.chenhui
@g
mail.com; Jason Jin
Subject: Re: [v3,4/5] powerpc/pm: support deep sleep feature on T104x
    
On Tue, Aug 02, 2016 at 07:59:31PM +0800, Chenhui Zhao wrote:

quoted

T104x has deep sleep feature, which can switch off most parts of
the SoC when it is in deep sleep mode. This way, it becomes more
energy-efficient.

The DDR controller will also be powered off in deep sleep. Therefore,
the last stage (the latter part of fsl_dp_enter_low) will run without
DDR
access. This piece of code and related TLBs are prefetched in advance.

Due to the different initialization code between 32-bit and 64-bit, they
have separate resume entry and precedure.

The feature supports 32-bit and 64-bit kernel mode.

Signed-off-by: Chenhui Zhao <redacted>
---
  arch/powerpc/include/asm/fsl_pm.h             |  24 ++
  arch/powerpc/kernel/asm-offsets.c             |  12 +
  arch/powerpc/kernel/fsl_booke_entry_mapping.S |  10 +
  arch/powerpc/kernel/head_64.S                 |   2 +-
  arch/powerpc/platforms/85xx/Makefile          |   1 +
  arch/powerpc/platforms/85xx/deepsleep.c       | 278 ++++++++++++++
  arch/powerpc/platforms/85xx/qoriq_pm.c        |  25 ++
  arch/powerpc/platforms/85xx/t104x_deepsleep.S | 531
++++++++++++++++++++++++++
  arch/powerpc/sysdev/fsl_rcpm.c                |   8 +-
  9 files changed, 889 insertions(+), 2 deletions(-)
  create mode 100644 arch/powerpc/platforms/85xx/deepsleep.c
  create mode 100644 arch/powerpc/platforms/85xx/t104x_deepsleep.S

diff --git a/arch/powerpc/include/asm/fsl_pm.h

b/arch/powerpc/include/asm/fsl_pm.h
index e05049b..48c2631 100644

--- a/arch/powerpc/include/asm/fsl_pm.h
+++ b/arch/powerpc/include/asm/fsl_pm.h

@@ -20,6 +20,7 @@

  
  #define PLAT_PM_SLEEP        20
  #define PLAT_PM_LPM20        30
+#define PLAT_PM_LPM35        40
  
  #define FSL_PM_SLEEP         (1 << 0)
  #define FSL_PM_DEEP_SLEEP    (1 << 1)

@@ -48,4 +49,27 @@ extern const struct fsl_pm_ops *qoriq_pm_ops;

  
  int __init fsl_rcpm_init(void);
  
+#ifdef CONFIG_FSL_QORIQ_PM
+int fsl_enter_deepsleep(void);
+int fsl_deepsleep_init(void);
+#else
+static inline int fsl_enter_deepsleep(void) { return -1; }
+static inline int fsl_deepsleep_init(void) { return -1; }
+#endif

Please return proper error codes.

Where can fsl_deepsleep_init() be called without CONFIG_FSL_QORIQ_PM?

[Chenhui] I can get rid of the ifdef here. And add it
in arch/powerpc/sysdev/fsl_rcpm.c.

No, this is the right place for the ifdef for functions that are called from
code that doesn't depend on CONFIG_FSL_QORIQ_PM.  But fsl_deepsleep_init()
is
called from deepsleep.c which is only built with CONFIG_FSL_QORIQ_PM, and
it's
hard to picture a scenario where it would be called from elsewhere.


[Chenhui] You are right. No need to enclose fsl_deepsleep_init() in the
ifdef.
                 But regarding fsl_enter_deepsleep(), it is called in
rcpm_v2_plat_enter_sleep()
                 in arch/powerpc/sysdev/fsl_rcpm.c. It still needs to be
enclosed in the ifdef.

Right.  That's why I specifically asked about fsl_deepsleep_init(). :-)

-Scott