Messages in this thread | | | Subject | Re: [PATCH v7 07/20] clk: tegra: clk-periph: Add save and restore support | From | Sowjanya Komatineni <> | Date | Thu, 1 Aug 2019 13:31:56 -0700 |
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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.
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.
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
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