Hi Simon, Magnus,
All supported Renesas ARM SoCs (except for Emma Mobile EV2) have clock
domains. Some SoCs also have power domains. To ensure proper operation
of on-SoC modules, module clocks must be ungated, and power domains must
be powered up when needed.
Currently the user can choose to build a kernel with power management
enabled or disabled:
- If CONFIG_PM=y, power domains and/or module clocks are handled
dynamically by Runtime PM and the generic power domain.
- If CONFIG_PM=n, power domains are assumed to be powered up by reset
state or by the boot loader, and module clocks are handled by the
legacy clock domain on driver (un)bind.
The latter is implemented using a platform bus notifier, which
applies not only to all on-SoC devices, but to all platform devices
present in the system.
To remove the dependency on implicit assumptions, and to get rid of the
peculiarities of the legacy clock domain, enable CONFIG_PM and
CONFIG_PM_GENERIC_DOMAINS unconditionally, for all Renesas ARM SoCs with
clock and/or power domains.
Patches:
- Patches 1 and 2 enable PM and PM_GENERIC_DOMAINS,
- Patch 3 removes the now unused legacy clock domain code for Renesas
ARM SoCs,
- Patch 4 relieves you from maintaining drivers/sh/, which is no
longer used on Renesas ARM SoCs, and returns it to the SuperH
people.
Notes:
- This does cause an increase in kernel size. Given bloat-o-meter
reports a modest increase of 26 KiB for an RZ/A1H kernel, this
should not be a problem, even when used on RZ/A1H with XIP and
internal RAM only.
- Patch 3 does break booting R-Car Gen2 boards using pre-v4.3 DTSes
that don't have power-domains properties,
- Patch 3 may unbreak SuperH-based ARCH_SHMOBILE platforms, which were
probably broken since v4.4 by commit 0ba58de231066e47 ("drivers: sh:
Get rid of CONFIG_ARCH_SHMOBILE_MULTI"),
- Currently CONFIG_PM=n doesn't work anyway on r8a7795 as "drivers:
sh: Handle PM_GENERIC_DOMAINS_OF=n with new r8a7795 CPG/MSSR
driver" isn't upstream.
For your convenience, I've also pushed this series to
git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git#topic/mandatory-pm-v1
Thanks for your comments!
Geert Uytterhoeven (4):
ARM: shmobile: Enable PM and PM_GENERIC_DOMAINS for SoCs with PM
Domains
arm64: renesas: Enable PM and PM_GENERIC_DOMAINS for SoCs with PM
Domains
drivers: sh: Stop using the legacy clock domain on ARM
MAINTAINERS: Drop drivers/sh/ for Renesas ARM
MAINTAINERS | 1 -
arch/arm/mach-shmobile/Kconfig | 13 ++++++++-----
arch/arm64/Kconfig.platforms | 3 ++-
drivers/Makefile | 1 -
drivers/sh/pm_runtime.c | 9 ---------
5 files changed, 10 insertions(+), 17 deletions(-)
--
1.9.1
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
