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Date: Wed, 31 Jul 2019 13:44:09 +0300
From: Dmitry Osipenko <digetx@...il.com>
To: Sowjanya Komatineni <skomatineni@...dia.com>,
thierry.reding@...il.com, jonathanh@...dia.com, tglx@...utronix.de,
jason@...edaemon.net, marc.zyngier@....com,
linus.walleij@...aro.org, stefan@...er.ch, mark.rutland@....com
Cc: pdeschrijver@...dia.com, pgaikwad@...dia.com, sboyd@...nel.org,
linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
jckuo@...dia.com, josephl@...dia.com, talho@...dia.com,
linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org,
mperttunen@...dia.com, spatra@...dia.com, robh+dt@...nel.org,
devicetree@...r.kernel.org
Subject: Re: [PATCH v7 07/20] clk: tegra: clk-periph: Add save and restore
support
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@...dia.com>
>> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.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.
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