[PATCH] ARM: S5PV210: add clocks (struct clk).

[MyungJoo Ham]

Hello.

On Mon, Jul 12, 2010 at 11:32 AM, Kukjin Kim <kgene.kim at samsung.com> wrote:
> MyungJoo Ham wrote:
>>
>> Hello, again.
>>
> Hi :-)
>
>> On Fri, Jul 9, 2010 at 11:59 AM, MyungJoo Ham <myungjoo.ham at samsung.com>
>> wrote:
>> > Hello,
>> >
>> > On Fri, Jul 9, 2010 at 11:36 AM, Kukjin Kim <kgene.kim at samsung.com> wrote:
>> >> MyungJoo Ham wrote:
>> >>>
>> >> Hi,
>> >>
>> >> Please include Ben Dooks in the Cc..
>> >> And...excuse me..who is benh at kernel.crashing.org?
>> >
>> > Ah.. I was confused by my own reply regarding common struct clk, which
>> > had benh at kernel.crashing.org as Cc. I'll update the CC setting.
>> >
>> >>
>> >>> Many clocks were not listed in the previous
>> >>> arch/arm/mach-s5pv210/clock.c
>> >>>
>> >>> We have added clocks defined as CLK_GATE_IPx[] in the user manual of
>> >>> S5PV210. However, the clocks that were not turned on at the boot time
>> >>> when tested with the previous kernel versions (2.6.32, 2.6.29) are
>> >>> defined in "init_clocks_disabled" so that they are turned off at the
>> >>> boot time.
>> >>
>> >> I think, no need to register all of clocks which are in the CLK_GATE_IPx
>> >> into 'init_clocks_disabled'..because it depends on each platform or project.
>> >>
>> >>>
>> >>> The clocks added from CLK_GATE_IPx are:
>> >>>       CSIS, JPEG, FIMC0 - 2, NFCON, SROMC, TVENC, HDMI, MIXER, VP,
>> >>>       DSIM, TSI, HOSTIF, MODEM, PCM0 - 2, I2C-HDMI-PHY, I2C-HDMI-DDC,
>> >>>       AC97, SPDIF, SECKEY, IEM-APC, IEM-IEC, CHIP-ID, PDMA0 - 1,
>> >>>       MDMA, DMC0 - 1, NANDXL, TZIC0 - 3, VIC0 - 3, SECJTAG,
>> CORESIGHT,
>> >>>       SDM, SECSS, SYSCON, GPIO, TZPC0 - 3
>> >>>
>> >>
>> >> For example...in the case of JPEG, FIMC, disabling is better at the booting
>> >> time..because can be enabled dynamically in the device driver when it is
>> >> used.
>> >> But if CORESIGHT which does not having own driver is disabled at that time,
>> >> basically can't use JTAG debugger.
>> >>
>> >> So need to sort out clocks to register into 'init_clocks_disabled'
>> >>
>> >
>> > Yes, I agree. I'll put some clocks including CORESIGHT out of
>> > init_clocks_disabled.
>> >
>>
>> Oh.. well, CORESIGHT is not included in init_clocks_disabled in the patch.
>>
>> In this patch, PDMA, MDMA, DMC, NANDXL, TZIC, VIC, SECJTAG, CORESIGHT,
>> SDM, SECSS, SYSCON, GPIO, and TZPC are not added to
>> init_clocks_disabled, but to init_clocks.
>>
>> Only others including CSIS, JPEG, FIMC0 - 2, NFCON, SROMC, TVENC,
>> HDMI, MIXER, VP, DSIM, TSI, HOSTIF, MODEM, PCM0 - 2, I2C-HDMI-PHY,
>> I2C-HDMI-DDC, AC97, SPDIF, SECKEY, IEM-APC, IEM-IEC, and CHIP-ID are
>> added to init_clocks_disabled. In this list, are there any clocks that
>> should be out of init_clocks_disabled?
>>
> Hmm..SROMC should be in 'init_clocks'...because eg., generally network which connected SROM bank, driver doesn't have clock enable code...
> And others, looks ok...but frankly, need to check again ;-)

Fine.

Anyway, I'm planning to include the initial states of clocks in struct clk.

That is, adding "unsigned int flag", which include "BOOT_ON", "BOOT",
and "CANNOT_DISABLE", and let s3c_register_clock function do the
operation accordingly.

This will merge init_clocks_disable and init_clocks and allow us more
control over clocks.Besides, it makes it easier to support powerdomain
and block-gating control. Note that if a powerdomain is controlled
with only reference counter, it may turn off a powerdomain with a
clock actually enabled (by the bootloader or by the process default)
but not ever "clk_enable"'d. Adding such information explicitly with
such flags can help.

I will send patches of clock-powerdomain support and clock-flag support soon.


>
>> >
>> > Anyway, I've been considering adding "flag" to struct clk, which has
>> > the following bits:
>> >
>> > #define CLKFLAGS_BOOT_ON        (0x1)
>> > #define CLKFLAGS_CANNOT_DISABLE (0x2)
>> > #define CLKFLAGS_ALWAYS_ON      (CLKFLAGS_BOOT_ON |
>> CLKFLAGS_CANNOT_DISABLE)
>> > #define CLKFLAGS_BOOT_OFF       (0x4) /* Force off when boot */
>> > #define CLKFLAGS_DEPRECATED     (0x8) /* Warn when clk_get'd */
>> > /* Note that CLKFLAGS_BOOT_ON and CLKFLAGS_CANNOT_DISABLE
>> overrides
>> >  * CLKFLAGS_BOOT_OFF */
>> >
>> > and merging init_clocks and init_clocks_disabled. This provides more
>> > precise control on clocks, and we've been using such features in other
>> > versions of the kernel. Besides, combined with
>> > powerdomain control, these flags are helpful on implementing
>> > powerdomain/block-gating control.
>> >
>> >
>> >>> Signed-off-by: MyungJoo Ham <myungjoo.ham at samsung.com>
>> >>> Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
>> >>> ---
>> >>>  arch/arm/mach-s5pv210/clock.c |  298
>> >>> ++++++++++++++++++++++++++++++++++++++++-
>> >>>  1 files changed, 297 insertions(+), 1 deletions(-)
>> >>>
>> >>> diff --git a/arch/arm/mach-s5pv210/clock.c b/arch/arm/mach-s5pv210/clock.c
>> >>> index b3d156c..aa2b1c5 100644
>> >>> --- a/arch/arm/mach-s5pv210/clock.c
>> >>> +++ b/arch/arm/mach-s5pv210/clock.c
>> >>
>> >> (snip)
>> >>
>> >> Thanks.
>> >>
>> >> Best regards,
>> >> Kgene.
>> >> --
>> >> Kukjin Kim <kgene.kim at samsung.com>, Senior Engineer,
>> >> SW Solution Development Team, Samsung Electronics Co., Ltd.
>> >>
>> >>
>
>
> Thanks.
>
> Best regards,
> Kgene.
> --
> Kukjin Kim <kgene.kim at samsung.com>, Senior Engineer,
> SW Solution Development Team, Samsung Electronics Co., Ltd.
>
>
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-- 
MyungJoo Ham (함명주), Ph.D.
Mobile Software Platform Lab,
Digital Media and Communications (DMC) Business
Samsung Electronics
cell: 82-10-6714-2858