From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>,
thierry.reding@gmail.com, jonathanh@nvidia.com,
tglx@linutronix.de, jason@lakedaemon.net, marc.zyngier@arm.com,
linus.walleij@linaro.org, stefan@agner.ch, mark.rutland@arm.com
Cc: pdeschrijver@nvidia.com, pgaikwad@nvidia.com, sboyd@kernel.org,
linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org,
jckuo@nvidia.com, josephl@nvidia.com, talho@nvidia.com,
linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
mperttunen@nvidia.com, spatra@nvidia.com, robh+dt@kernel.org,
devicetree@vger.kernel.org
Subject: Re: [PATCH v7 07/20] clk: tegra: clk-periph: Add save and restore support
Date: Fri, 2 Aug 2019 16:51:58 -0700 [thread overview]
Message-ID: <d82de63a-02a3-8fb0-57e7-7fe00d6b86ab@nvidia.com> (raw)
In-Reply-To: <73cd521b-782c-7fb2-d904-ae8b07927d47@gmail.com>
On 8/2/19 2:15 PM, Dmitry Osipenko wrote:
> 02.08.2019 23:32, Sowjanya Komatineni пишет:
>> On 8/2/19 1:17 PM, Dmitry Osipenko wrote:
>>> 02.08.2019 23:13, Dmitry Osipenko пишет:
>>>> 02.08.2019 21:33, Sowjanya Komatineni пишет:
>>>>> On 8/2/19 5:38 AM, Dmitry Osipenko wrote:
>>>>>> 02.08.2019 2:49, Sowjanya Komatineni пишет:
>>>>>>> On 8/1/19 4:19 PM, Sowjanya Komatineni wrote:
>>>>>>>> On 8/1/19 2:30 PM, Sowjanya Komatineni wrote:
>>>>>>>>> On 8/1/19 1:54 PM, Dmitry Osipenko wrote:
>>>>>>>>>> 01.08.2019 23:31, Sowjanya Komatineni пишет:
>>>>>>>>>>> On 8/1/19 1:17 PM, Dmitry Osipenko wrote:
>>>>>>>>>>>> 01.08.2019 22:42, Sowjanya Komatineni пишет:
>>>>>>>>>>>>> On 8/1/19 12:00 PM, Dmitry Osipenko wrote:
>>>>>>>>>>>>>> 01.08.2019 20:58, Sowjanya Komatineni пишет:
>>>>>>>>>>>>>>> On 7/31/19 4:09 PM, Sowjanya Komatineni wrote:
>>>>>>>>>>>>>>>> On 7/31/19 3:44 AM, Dmitry Osipenko wrote:
>>>>>>>>>>>>>>>>> 31.07.2019 12:50, Dmitry Osipenko пишет:
>>>>>>>>>>>>>>>>>> 31.07.2019 3:20, Sowjanya Komatineni пишет:
>>>>>>>>>>>>>>>>>>> This patch implements save and restore context for
>>>>>>>>>>>>>>>>>>> peripheral
>>>>>>>>>>>>>>>>>>> fixed
>>>>>>>>>>>>>>>>>>> clock ops, peripheral gate clock ops, sdmmc mux clock
>>>>>>>>>>>>>>>>>>> ops, and
>>>>>>>>>>>>>>>>>>> peripheral clock ops.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> During system suspend, core power goes off and looses the
>>>>>>>>>>>>>>>>>>> settings
>>>>>>>>>>>>>>>>>>> of the Tegra CAR controller registers.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> So during suspend entry clock and reset state of
>>>>>>>>>>>>>>>>>>> peripherals is
>>>>>>>>>>>>>>>>>>> saved
>>>>>>>>>>>>>>>>>>> and on resume they are restored to have clocks back to
>>>>>>>>>>>>>>>>>>> same
>>>>>>>>>>>>>>>>>>> rate and
>>>>>>>>>>>>>>>>>>> state as before suspend.
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> Acked-by: Thierry Reding <treding@nvidia.com>
>>>>>>>>>>>>>>>>>>> Signed-off-by: Sowjanya Komatineni
>>>>>>>>>>>>>>>>>>> <skomatineni@nvidia.com>
>>>>>>>>>>>>>>>>>>> ---
>>>>>>>>>>>>>>>>>>> drivers/clk/tegra/clk-periph-fixed.c | 33
>>>>>>>>>>>>>>>>>>> ++++++++++++++++++++++++++++++++
>>>>>>>>>>>>>>>>>>> drivers/clk/tegra/clk-periph-gate.c | 34
>>>>>>>>>>>>>>>>>>> +++++++++++++++++++++++++++++++++
>>>>>>>>>>>>>>>>>>> drivers/clk/tegra/clk-periph.c | 37
>>>>>>>>>>>>>>>>>>> ++++++++++++++++++++++++++++++++++++
>>>>>>>>>>>>>>>>>>> drivers/clk/tegra/clk-sdmmc-mux.c | 28
>>>>>>>>>>>>>>>>>>> +++++++++++++++++++++++++++
>>>>>>>>>>>>>>>>>>> drivers/clk/tegra/clk.h | 6 ++++++
>>>>>>>>>>>>>>>>>>> 5 files changed, 138 insertions(+)
>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>> diff --git a/drivers/clk/tegra/clk-periph-fixed.c
>>>>>>>>>>>>>>>>>>> b/drivers/clk/tegra/clk-periph-fixed.c
>>>>>>>>>>>>>>>>>>> index c088e7a280df..21b24530fa00 100644
>>>>>>>>>>>>>>>>>>> --- a/drivers/clk/tegra/clk-periph-fixed.c
>>>>>>>>>>>>>>>>>>> +++ b/drivers/clk/tegra/clk-periph-fixed.c
>>>>>>>>>>>>>>>>>>> @@ -60,11 +60,44 @@
>>>>>>>>>>>>>>>>>>> tegra_clk_periph_fixed_recalc_rate(struct
>>>>>>>>>>>>>>>>>>> clk_hw *hw,
>>>>>>>>>>>>>>>>>>> return (unsigned long)rate;
>>>>>>>>>>>>>>>>>>> }
>>>>>>>>>>>>>>>>>>> +static int
>>>>>>>>>>>>>>>>>>> tegra_clk_periph_fixed_save_context(struct
>>>>>>>>>>>>>>>>>>> clk_hw
>>>>>>>>>>>>>>>>>>> *hw)
>>>>>>>>>>>>>>>>>>> +{
>>>>>>>>>>>>>>>>>>> + struct tegra_clk_periph_fixed *fixed =
>>>>>>>>>>>>>>>>>>> to_tegra_clk_periph_fixed(hw);
>>>>>>>>>>>>>>>>>>> + u32 mask = 1 << (fixed->num % 32);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + fixed->enb_ctx = readl_relaxed(fixed->base +
>>>>>>>>>>>>>>>>>>> fixed->regs->enb_reg) &
>>>>>>>>>>>>>>>>>>> + mask;
>>>>>>>>>>>>>>>>>>> + fixed->rst_ctx = readl_relaxed(fixed->base +
>>>>>>>>>>>>>>>>>>> fixed->regs->rst_reg) &
>>>>>>>>>>>>>>>>>>> + mask;
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + return 0;
>>>>>>>>>>>>>>>>>>> +}
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> +static void
>>>>>>>>>>>>>>>>>>> tegra_clk_periph_fixed_restore_context(struct
>>>>>>>>>>>>>>>>>>> clk_hw
>>>>>>>>>>>>>>>>>>> *hw)
>>>>>>>>>>>>>>>>>>> +{
>>>>>>>>>>>>>>>>>>> + struct tegra_clk_periph_fixed *fixed =
>>>>>>>>>>>>>>>>>>> to_tegra_clk_periph_fixed(hw);
>>>>>>>>>>>>>>>>>>> + u32 mask = 1 << (fixed->num % 32);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + if (fixed->enb_ctx)
>>>>>>>>>>>>>>>>>>> + writel_relaxed(mask, fixed->base +
>>>>>>>>>>>>>>>>>>> fixed->regs->enb_set_reg);
>>>>>>>>>>>>>>>>>>> + else
>>>>>>>>>>>>>>>>>>> + writel_relaxed(mask, fixed->base +
>>>>>>>>>>>>>>>>>>> fixed->regs->enb_clr_reg);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + udelay(2);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + if (!fixed->rst_ctx) {
>>>>>>>>>>>>>>>>>>> + udelay(5); /* reset propogation delay */
>>>>>>>>>>>>>>>>>>> + writel_relaxed(mask, fixed->base +
>>>>>>>>>>>>>>>>>>> fixed->regs->rst_reg);
>>>>>>>>>>>>>>>>>>> + }
>>>>>>>>>>>>>>>>>>> +}
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> static const struct clk_ops
>>>>>>>>>>>>>>>>>>> tegra_clk_periph_fixed_ops
>>>>>>>>>>>>>>>>>>> = {
>>>>>>>>>>>>>>>>>>> .is_enabled =
>>>>>>>>>>>>>>>>>>> tegra_clk_periph_fixed_is_enabled,
>>>>>>>>>>>>>>>>>>> .enable = tegra_clk_periph_fixed_enable,
>>>>>>>>>>>>>>>>>>> .disable = tegra_clk_periph_fixed_disable,
>>>>>>>>>>>>>>>>>>> .recalc_rate =
>>>>>>>>>>>>>>>>>>> tegra_clk_periph_fixed_recalc_rate,
>>>>>>>>>>>>>>>>>>> + .save_context = tegra_clk_periph_fixed_save_context,
>>>>>>>>>>>>>>>>>>> + .restore_context =
>>>>>>>>>>>>>>>>>>> tegra_clk_periph_fixed_restore_context,
>>>>>>>>>>>>>>>>>>> };
>>>>>>>>>>>>>>>>>>> struct clk
>>>>>>>>>>>>>>>>>>> *tegra_clk_register_periph_fixed(const
>>>>>>>>>>>>>>>>>>> char
>>>>>>>>>>>>>>>>>>> *name,
>>>>>>>>>>>>>>>>>>> diff --git a/drivers/clk/tegra/clk-periph-gate.c
>>>>>>>>>>>>>>>>>>> b/drivers/clk/tegra/clk-periph-gate.c
>>>>>>>>>>>>>>>>>>> index 4b31beefc9fc..6ba5b08e0787 100644
>>>>>>>>>>>>>>>>>>> --- a/drivers/clk/tegra/clk-periph-gate.c
>>>>>>>>>>>>>>>>>>> +++ b/drivers/clk/tegra/clk-periph-gate.c
>>>>>>>>>>>>>>>>>>> @@ -25,6 +25,8 @@ static
>>>>>>>>>>>>>>>>>>> DEFINE_SPINLOCK(periph_ref_lock);
>>>>>>>>>>>>>>>>>>> #define read_rst(gate) \
>>>>>>>>>>>>>>>>>>> readl_relaxed(gate->clk_base +
>>>>>>>>>>>>>>>>>>> (gate->regs->rst_reg))
>>>>>>>>>>>>>>>>>>> +#define write_rst_set(val, gate) \
>>>>>>>>>>>>>>>>>>> + writel_relaxed(val, gate->clk_base +
>>>>>>>>>>>>>>>>>>> (gate->regs->rst_set_reg))
>>>>>>>>>>>>>>>>>>> #define write_rst_clr(val, gate) \
>>>>>>>>>>>>>>>>>>> writel_relaxed(val, gate->clk_base +
>>>>>>>>>>>>>>>>>>> (gate->regs->rst_clr_reg))
>>>>>>>>>>>>>>>>>>> @@ -110,10 +112,42 @@ static void
>>>>>>>>>>>>>>>>>>> clk_periph_disable(struct
>>>>>>>>>>>>>>>>>>> clk_hw *hw)
>>>>>>>>>>>>>>>>>>> spin_unlock_irqrestore(&periph_ref_lock, flags);
>>>>>>>>>>>>>>>>>>> }
>>>>>>>>>>>>>>>>>>> +static int clk_periph_gate_save_context(struct
>>>>>>>>>>>>>>>>>>> clk_hw
>>>>>>>>>>>>>>>>>>> *hw)
>>>>>>>>>>>>>>>>>>> +{
>>>>>>>>>>>>>>>>>>> + struct tegra_clk_periph_gate *gate =
>>>>>>>>>>>>>>>>>>> to_clk_periph_gate(hw);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + gate->clk_state_ctx = read_enb(gate) &
>>>>>>>>>>>>>>>>>>> periph_clk_to_bit(gate);
>>>>>>>>>>>>>>>>>>> + gate->rst_state_ctx = read_rst(gate) &
>>>>>>>>>>>>>>>>>>> periph_clk_to_bit(gate);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + return 0;
>>>>>>>>>>>>>>>>>>> +}
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> +static void clk_periph_gate_restore_context(struct
>>>>>>>>>>>>>>>>>>> clk_hw
>>>>>>>>>>>>>>>>>>> *hw)
>>>>>>>>>>>>>>>>>>> +{
>>>>>>>>>>>>>>>>>>> + struct tegra_clk_periph_gate *gate =
>>>>>>>>>>>>>>>>>>> to_clk_periph_gate(hw);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + if (gate->clk_state_ctx)
>>>>>>>>>>>>>>>>>>> + write_enb_set(periph_clk_to_bit(gate), gate);
>>>>>>>>>>>>>>>>>>> + else
>>>>>>>>>>>>>>>>>>> + write_enb_clr(periph_clk_to_bit(gate), gate);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + udelay(5);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + if (!(gate->flags & TEGRA_PERIPH_NO_RESET) &&
>>>>>>>>>>>>>>>>>>> + !(gate->flags & TEGRA_PERIPH_MANUAL_RESET)) {
>>>>>>>>>>>>>>>>>>> + if (gate->rst_state_ctx)
>>>>>>>>>>>>>>>>>>> + write_rst_set(periph_clk_to_bit(gate), gate);
>>>>>>>>>>>>>>>>>>> + else
>>>>>>>>>>>>>>>>>>> + write_rst_clr(periph_clk_to_bit(gate), gate);
>>>>>>>>>>>>>>>>>>> + }
>>>>>>>>>>>>>>>>>>> +}
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> const struct clk_ops tegra_clk_periph_gate_ops = {
>>>>>>>>>>>>>>>>>>> .is_enabled = clk_periph_is_enabled,
>>>>>>>>>>>>>>>>>>> .enable = clk_periph_enable,
>>>>>>>>>>>>>>>>>>> .disable = clk_periph_disable,
>>>>>>>>>>>>>>>>>>> + .save_context = clk_periph_gate_save_context,
>>>>>>>>>>>>>>>>>>> + .restore_context = clk_periph_gate_restore_context,
>>>>>>>>>>>>>>>>>>> };
>>>>>>>>>>>>>>>>>>> struct clk *tegra_clk_register_periph_gate(const
>>>>>>>>>>>>>>>>>>> char *name,
>>>>>>>>>>>>>>>>>>> diff --git a/drivers/clk/tegra/clk-periph.c
>>>>>>>>>>>>>>>>>>> b/drivers/clk/tegra/clk-periph.c
>>>>>>>>>>>>>>>>>>> index 58437da25156..06fb62955768 100644
>>>>>>>>>>>>>>>>>>> --- a/drivers/clk/tegra/clk-periph.c
>>>>>>>>>>>>>>>>>>> +++ b/drivers/clk/tegra/clk-periph.c
>>>>>>>>>>>>>>>>>>> @@ -99,6 +99,37 @@ static void clk_periph_disable(struct
>>>>>>>>>>>>>>>>>>> clk_hw
>>>>>>>>>>>>>>>>>>> *hw)
>>>>>>>>>>>>>>>>>>> gate_ops->disable(gate_hw);
>>>>>>>>>>>>>>>>>>> }
>>>>>>>>>>>>>>>>>>> +static int clk_periph_save_context(struct
>>>>>>>>>>>>>>>>>>> clk_hw *hw)
>>>>>>>>>>>>>>>>>>> +{
>>>>>>>>>>>>>>>>>>> + struct tegra_clk_periph *periph = to_clk_periph(hw);
>>>>>>>>>>>>>>>>>>> + const struct clk_ops *gate_ops = periph->gate_ops;
>>>>>>>>>>>>>>>>>>> + struct clk_hw *gate_hw = &periph->gate.hw;
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + if (!(periph->gate.flags & TEGRA_PERIPH_NO_GATE))
>>>>>>>>>>>>>>>>>>> + gate_ops->save_context(gate_hw);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + periph->parent_ctx = clk_periph_get_parent(hw);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + return 0;
>>>>>>>>>>>>>>>>>>> +}
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> +static void clk_periph_restore_context(struct clk_hw
>>>>>>>>>>>>>>>>>>> *hw)
>>>>>>>>>>>>>>>>>>> +{
>>>>>>>>>>>>>>>>>>> + struct tegra_clk_periph *periph = to_clk_periph(hw);
>>>>>>>>>>>>>>>>>>> + const struct clk_ops *gate_ops = periph->gate_ops;
>>>>>>>>>>>>>>>>>>> + struct clk_hw *gate_hw = &periph->gate.hw;
>>>>>>>>>>>>>>>>>>> + const struct clk_ops *div_ops = periph->div_ops;
>>>>>>>>>>>>>>>>>>> + struct clk_hw *div_hw = &periph->divider.hw;
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + clk_periph_set_parent(hw, periph->parent_ctx);
>>>>>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>>>>>> + if (!(periph->gate.flags & TEGRA_PERIPH_NO_DIV))
>>>>>>>>>>>>>>>>>>> + div_ops->restore_context(div_hw);
>>>>>>>>>>>>>>>>>> Could you please point to where the divider's
>>>>>>>>>>>>>>>>>> save_context()
>>>>>>>>>>>>>>>>>> happens?
>>>>>>>>>>>>>>>>>> Because I can't see it.
>>>>>>>>>>>>>>>>> Ah, I now see that there is no need to save the dividers
>>>>>>>>>>>>>>>>> context
>>>>>>>>>>>>>>>>> because
>>>>>>>>>>>>>>>>> clk itself has enough info that is needed for the context's
>>>>>>>>>>>>>>>>> restoring
>>>>>>>>>>>>>>>>> (like I pointed in the review to v6).
>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>> Looks like you could also implement a new
>>>>>>>>>>>>>>>>> clk_hw_get_parent_index()
>>>>>>>>>>>>>>>>> generic helper to get the index instead of storing it
>>>>>>>>>>>>>>>>> manually.
>>>>>>>>>>>>>>>> clk_periph_get_parent basically invokes existing clk_mux_ops
>>>>>>>>>>>>>>>> get_parent() which is then saved in tegra_clk_periph.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> All existing drivers are using directly get_parent() from
>>>>>>>>>>>>>>>> clk_mux
>>>>>>>>>>>>>>>> which actually gets index from the register read.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> To have this more generic w.r.t save/restore context
>>>>>>>>>>>>>>>> point of
>>>>>>>>>>>>>>>> view,
>>>>>>>>>>>>>>>> probably instead of implementing new get_parent_index
>>>>>>>>>>>>>>>> helper,
>>>>>>>>>>>>>>>> I think
>>>>>>>>>>>>>>>> its better to implement save_context and restore_context to
>>>>>>>>>>>>>>>> clk_mux_ops along with creating parent_index field into
>>>>>>>>>>>>>>>> clk_mux to
>>>>>>>>>>>>>>>> cache index during set_parent.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> So we just need to invoke mux_ops save_context and
>>>>>>>>>>>>>>>> restore_context.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I hope its ok to add save/restore context to clk_mux_ops
>>>>>>>>>>>>>>> to be
>>>>>>>>>>>>>>> more
>>>>>>>>>>>>>>> generic w.r.t save/restore context rather than
>>>>>>>>>>>>>>> get_parent_index
>>>>>>>>>>>>>>> API.
>>>>>>>>>>>>>>> Please confirm if you agree.
>>>>>>>>>>>>>> Sounds like a good idea. I see that there is a 'restoring'
>>>>>>>>>>>>>> helper for
>>>>>>>>>>>>>> the generic clk_gate, seems something similar could be done
>>>>>>>>>>>>>> for the
>>>>>>>>>>>>>> clk_mux. And looks like anyway you'll need to associate the
>>>>>>>>>>>>>> parent
>>>>>>>>>>>>>> clock
>>>>>>>>>>>>>> with the hw index in order to restore the muxing.
>>>>>>>>>>>>> by 'restoring' helper for generic clk_gate, are you
>>>>>>>>>>>>> referring to
>>>>>>>>>>>>> clk_gate_restore_context API?
>>>>>>>>>>>> Yes.
>>>>>>>>>>>>
>>>>>>>>>>>>> clk_gate_restore_context is API that's any clk drivers can
>>>>>>>>>>>>> use for
>>>>>>>>>>>>> clk_gate operation restore for custom gate clk_ops.
>>>>>>>>>>>>>
>>>>>>>>>>>>> But clk-periph is directly using generic clk_mux ops from
>>>>>>>>>>>>> clk_mux
>>>>>>>>>>>>> so I
>>>>>>>>>>>>> think we should add .restore_context to clk_mux_ops and then
>>>>>>>>>>>>> during
>>>>>>>>>>>>> clk-periph restore need to invoke mux_ops->restore_context.
>>>>>>>>>>>> I'm not sure whether it will be good for every driver that uses
>>>>>>>>>>>> generic
>>>>>>>>>>>> clk_mux ops. Should be more flexible to have a generic helper
>>>>>>>>>>>> function
>>>>>>>>>>>> that any driver could use in order to restore the clock's
>>>>>>>>>>>> parent.
>>>>>>>>>>>>
>>>>>>>>>>>> The clk-periph restoring also includes case of combining divider
>>>>>>>>>>>> and
>>>>>>>>>>>> parent restoring, so generic helper could be useful in that case
>>>>>>>>>>>> as well.
>>>>>>>>>>>>
>>>>>>>>>>>> It also looks like you could actually use the
>>>>>>>>>>>> clk_gate_restore_context()
>>>>>>>>>>>> instead of manually saving the clock's enable-state, couldn't
>>>>>>>>>>>> you?
>>>>>>>>>>> ok for clk_mux, can add generic clk_mux_restore_context API
>>>>>>>>>>> rather
>>>>>>>>>>> than
>>>>>>>>>>> using restore_context in clk_ops and will invoke that during
>>>>>>>>>>> clk_periph
>>>>>>>>>>> restore.
>>>>>>>>>>>
>>>>>>> digging thru looks like for clk_periph source restore instead of
>>>>>>> clk_mux_restore_context, i can directly do clk_hw_get_parent and
>>>>>>> clk_set_parent with mux_hw as they invoke mux_ops get/set parent
>>>>>>> anyway.
>>>>>>> Will do this for periph clk mux
Just to be clear, clk_mux don't have cached parent. get_parent is by
register read. So, cant directly use get_parent and then set during restore.
So will create both clk_mux_save/restore_context in generic clk driver
and will invoke them during tegra peripheral clock suspend/resume.
>>>>>>>>>>> Reg clk_gate, looks like we cant use generic
>>>>>>>>>>> clk_gate_restore_context
>>>>>>>>>>> for clk-periph as it calls enable/disable callbacks and
>>>>>>>>>>> clk_periph_enable/disable in clk-periph-gate also updated
>>>>>>>>>>> refcnt and
>>>>>>>>>>> depending on that actual enable/disable is set.
>>>>>>>>>>>
>>>>>>>>>>> During suspend, peripherals that are already enabled have their
>>>>>>>>>>> refcnt >
>>>>>>>>>>> 1, so they dont go thru enable/disable on restore if we use same
>>>>>>>>>>> enable/disable callback.
>>>>>>>>>> Looks like you could just decrement the gate's enable_refcnt on
>>>>>>>>>> save_context, wouldn't that work?
>>>>>>>>>>
>>>>>>>> gate->enable_refcnt is within clk-periph-gate which gets updated
>>>>>>>> when
>>>>>>>> enable/disable callbacks get execute thru clk_core_enable/disable.
>>>>>>>> But actual enable_count used in clk_gate_restore_context is the one
>>>>>>>> which gets updated with in the clk core enable/disable functions
>>>>>>>> which
>>>>>>>> invokes these callbacks. Depending on this enable_count in clk
>>>>>>>> core it
>>>>>>>> invokes enable/disable.
>>>>>>>>
>>>>>>>> So, this will cause mismatch if we handle refcnt during save/restore
>>>>>>>> of tegra_clk_periph_gate_ops and also enable/disable thru this
>>>>>>>> clk_gate_restore_context is based on enable_count from clk core.
>>>>>>>>
>>>>>>>>>>> Also to align exact reset state along with CLK (like for case
>>>>>>>>>>> where
>>>>>>>>>>> CLK
>>>>>>>>>>> is enabled but peripheral might be in reset state), implemented
>>>>>>>>>>> save/restore in tegra specific tegra_clk_periph_gate_ops
>>>>>>>>>> I'm wondering whether instead of saving/restoring reset-state of
>>>>>>>>>> every
>>>>>>>>>> clock, you could simply save/restore the whole RST_DEV_x_SET
>>>>>>>>>> register.
>>>>>>>>>> Couldn't you?
>>>>>>>>> Thats what I was doing in first version of patch. But later as we
>>>>>>>>> moved to use clk_save_context and clk_restore_context, peripheral
>>>>>>>>> clk_hw RST & CLK enables happen thru its corresponding save/restore
>>>>>>>>> after source restore
>>>>>>>> Also, to align both CLK & RST to the exact state of register, doing
>>>>>>>> save/restore in tegra_clk_periph_gate_ops and invoking this after
>>>>>>>> source restore for peripheral clock, seems cleaner to avoid any
>>>>>>>> misconfiguration b/w rst & clk settings.
>>>>>>>>
>>>>>> It looks to me that it is very wasteful to store/restore each
>>>>>> individual
>>>>>> gate and reset state, also given that some of them are shared. I think
>>>>>> that the gates and resets should be restored separately for the
>>>>>> peripherals by a custom tegra_clk_save/restore_periph_gates/resets().
>>>>> clk_periph_fixed_disable just disables clock only without deasserting
>>>>> the corresponding peripheral.
>>>>>
>>>>> corresponding peripheral drivers can also issue reset assert/deassert
>>>>> thru reset_control_assert/deassert.
>>>>>
>>>>> So, we will not get the actual state of clk and rst unless we read and
>>>>> save state of reset and clock separately during save_context.
>>>>>
>>>>> Currently patch is already using custom
>>>>> tegra_clk_periph_fixed_save/restore_context for corresponding clk_ops.
>>>>> Are you suggesting to do save and restore of complete CLK_ENB/RST_DEV
>>>>> register settings instead of individual peripheral bits?
>>>> Yes, I'm suggesting to do a complete ungate/reset handling of the
>>>> devices in a separate function. All enabling/deassertion will be done in
>>>> a single hop, hence using 7us delay and four u32 words, which is much
>>>> nicer IMHO.
>>> Actually six words, three for CLKs and three for RSTs.
>> OK, So with separate function doing complete register save/restore for
>> clk & rst, we can't do this thru clk_ops save/restore as clk_ops
>> save_restore happens per peripheral wise. So if we decide to do this,
>> then this should be invoked in clk-tegra210 driver suspend/resume.
> Yes, per-clock save/restore should be used for setting rate and parent.
> The ungating and resetting could be done separately to keep things cleaner.
>
next prev parent reply other threads:[~2019-08-02 23:51 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-31 0:20 [PATCH v7 00/20] SC7 entry and exit support for Tegra210 Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 01/20] pinctrl: tegra: Add suspend and resume support Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 02/20] pinctrl: tegra210: Add Tegra210 pinctrl pm ops Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 03/20] clk: tegra: divider: Save and restore divider rate Sowjanya Komatineni
2019-07-31 10:49 ` Dmitry Osipenko
2019-07-31 0:20 ` [PATCH v7 04/20] clk: tegra: pllout: Save and restore pllout context Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 05/20] clk: tegra: pll: Save and restore pll context Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 06/20] clk: tegra: Support for OSC context save and restore Sowjanya Komatineni
2019-07-31 11:11 ` Dmitry Osipenko
2019-07-31 21:04 ` Sowjanya Komatineni
2019-08-01 10:53 ` Dmitry Osipenko
2019-08-01 18:06 ` Sowjanya Komatineni
2019-08-01 18:42 ` Dmitry Osipenko
2019-07-31 0:20 ` [PATCH v7 07/20] clk: tegra: clk-periph: Add save and restore support Sowjanya Komatineni
2019-07-31 9:50 ` Dmitry Osipenko
2019-07-31 10:44 ` Dmitry Osipenko
2019-07-31 23:09 ` Sowjanya Komatineni
2019-08-01 17:58 ` Sowjanya Komatineni
2019-08-01 19:00 ` Dmitry Osipenko
2019-08-01 19:42 ` Sowjanya Komatineni
2019-08-01 20:17 ` Dmitry Osipenko
2019-08-01 20:31 ` Sowjanya Komatineni
2019-08-01 20:54 ` Dmitry Osipenko
2019-08-01 21:30 ` Sowjanya Komatineni
2019-08-01 23:19 ` Sowjanya Komatineni
2019-08-01 23:49 ` Sowjanya Komatineni
2019-08-02 12:38 ` Dmitry Osipenko
2019-08-02 18:33 ` Sowjanya Komatineni
2019-08-02 20:13 ` Dmitry Osipenko
2019-08-02 20:17 ` Dmitry Osipenko
2019-08-02 20:32 ` Sowjanya Komatineni
2019-08-02 21:15 ` Dmitry Osipenko
2019-08-02 21:18 ` Sowjanya Komatineni
2019-08-02 23:51 ` Sowjanya Komatineni [this message]
2019-08-03 10:33 ` Dmitry Osipenko
2019-08-03 17:01 ` Sowjanya Komatineni
2019-08-03 23:44 ` Sowjanya Komatineni
2019-08-04 12:24 ` Dmitry Osipenko
2019-08-04 12:31 ` Dmitry Osipenko
2019-08-02 12:32 ` Dmitry Osipenko
2019-08-02 18:43 ` Sowjanya Komatineni
2019-08-02 20:20 ` Dmitry Osipenko
2019-08-02 20:37 ` Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 08/20] clk: tegra: clk-super: Fix to enable PLLP branches to CPU Sowjanya Komatineni
2019-07-31 10:14 ` Dmitry Osipenko
2019-07-31 0:20 ` [PATCH v7 09/20] clk: tegra: clk-super: Add save and restore support Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 10/20] clk: tegra: clk-dfll: Add suspend and resume support Sowjanya Komatineni
2019-07-31 10:12 ` Dmitry Osipenko
2019-07-31 0:20 ` [PATCH v7 11/20] cpufreq: tegra124: " Sowjanya Komatineni
2019-07-31 10:23 ` Dmitry Osipenko
2019-07-31 11:14 ` Dmitry Osipenko
2019-07-31 21:05 ` Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 12/20] clk: tegra210: Use fence_udelay during PLLU init Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 13/20] clk: tegra210: Add suspend and resume support Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 14/20] soc/tegra: pmc: Allow to support more tegras wake Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 15/20] soc/tegra: pmc: Add pmc wake support for tegra210 Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 16/20] arm64: tegra: Enable wake from deep sleep on RTC alarm Sowjanya Komatineni
2019-07-31 11:04 ` Dmitry Osipenko
2019-07-31 21:08 ` Sowjanya Komatineni
2019-08-01 10:43 ` Dmitry Osipenko
2019-08-01 17:56 ` Sowjanya Komatineni
2019-08-01 18:39 ` Dmitry Osipenko
2019-07-31 0:20 ` [PATCH v7 17/20] soc/tegra: pmc: Configure core power request polarity Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 18/20] soc/tegra: pmc: Configure deep sleep control settings Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 19/20] arm64: dts: tegra210-p2180: Jetson TX1 SC7 timings Sowjanya Komatineni
2019-07-31 0:20 ` [PATCH v7 20/20] arm64: dts: tegra210-p3450: Jetson Nano " Sowjanya Komatineni
2019-07-31 21:10 [PATCH v7 00/20] SC7 entry and exit support for Tegra210 Sowjanya Komatineni
2019-07-31 21:10 ` [PATCH v7 07/20] clk: tegra: clk-periph: Add save and restore support Sowjanya Komatineni
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