Re: [PATCH 8/8] ARM / shmobile: Support for I/O PM domains for SH7372 (v5)

On Wed, Jun 15, 2011 at 6:16 AM, Rafael J. Wysocki [off-list ref] wrote:

On Tuesday, June 14, 2011, Magnus Damm wrote:

quoted

On Sun, Jun 12, 2011 at 5:40 AM, Rafael J. Wysocki [off-list ref] wrote:

quoted

From: Rafael J. Wysocki <redacted>

Use the generic power domains support introduced by the previous
patch to implement support for power domains on SH7372.

Signed-off-by: Rafael J. Wysocki <redacted>
---

Thanks for your work on this. I just tried this on my Mackerel board,
but I can't seem to get the pd_power_up() and pd_power_down()
callbacks to be executed. It is probably a misconfiguration from my
side.

They trigger for me e.g. after doing

# echo 3 > /sys/devices/platform/sh_mobile_lcdc_fb.0/graphics/fb0/blank

Attached is the .config I've been using.

Thanks, I can trigger using sysfs and your kernel configuration.

However, I assumed it also would work when the sceen saver kicked in.
I recall it being fbcon that controls the screen save, perhaps
something else. So just wait a bit and see if you also can reproduce
it. The console gets black but the power is still on...

Also forcing to go back to powered-on state (see below) doesn't work that well:
# echo 0 > /sys/devices/platform/sh_mobile_lcdc_fb.0/graphics/fb0/blank

It looks like we loose the panning information somehow. Most likely a
LCDC driver bug. Unless the driver callbacks are not being invoked as
expected.

Also, there is garbage in on the screen if FB_SH_MOBILE_MERAM is
enabled. The MERAM hardware is a 1.5 MiB memory block that can be used
as a LCD cache. It sits in the same hardware power domain as the
LCDCs. I don't think the MERAM software supports power down
unfortunately. Disabling MERAM support removes the garbage on the
screen.

quoted

Here's some feedback on the sh7372-specific code:

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--- linux-2.6.orig/arch/arm/mach-shmobile/Kconfig
+++ linux-2.6/arch/arm/mach-shmobile/Kconfig

@@ -19,6 +19,7 @@ config ARCH_SH7372

       select CPU_V7
       select SH_CLK_CPG
       select ARCH_WANT_OPTIONAL_GPIOLIB
+       select PM_GENERIC_DOMAINS

We want to support a single ARM binary for multiple boards,

Surely CONFIG_ARCH_SH7372 will be set in that binary?

quoted

so this should be enabled for all SoCs in mach-shmobile as a whole.

OK, where exactly do you want me to move it?

Ideally to ARCH_SHMOBILE in arch/arm/Kconfig.

quoted

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--- linux-2.6.orig/arch/arm/mach-shmobile/pm-sh7372.c
+++ linux-2.6/arch/arm/mach-shmobile/pm-sh7372.c

@@ -15,16 +15,97 @@

 #include <linux/list.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
+#include <linux/platform_device.h>
 #include <asm/system.h>
 #include <asm/io.h>
 #include <asm/tlbflush.h>
 #include <mach/common.h>
+#include <mach/sh7372.h>

 #define SMFRAM 0xe6a70000
 #define SYSTBCR 0xe6150024
 #define SBAR 0xe6180020
 #define APARMBAREA 0xe6f10020

+#define SPDCR 0xe6180008
+#define SWUCR 0xe6180014
+#define PSTR 0xe6180080
+
+struct sh7372_domain_data {
+       unsigned int bit_shift;
+};

Is it possible to make struct sh7372_domain_data include struct
generic_pm_domain?

It should be possible to do that.

Do I understand it correctly that you want one structure definition per
power domain instead of the two?

Yes, at least that's what I would do to keep the data together. I
don't care that much though, so feel free to implement it however
you'd like.

quoted

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+core_initcall(sh7372_power_domains_init);

This initcall is going to be executed regardless which SoC we're
running on. We only want it called for sh7372 though.

OK

quoted

If you look at other SoC-specific code then you will notice that
initcalls are only used for functions in mach-shmobile/ that are
common for all SoCs implemented under mach-shmobile.

You most likely want to initialize from sh7372_pm_init(), but for that
to work you probably have to reorder your code inside mackerel_init().

OK, I'll figure out how to do the initialization correctly.

Please do!

Thanks,

/ magnus