Messages in this thread | | | Subject | Re: [PATCH v7 07/20] clk: tegra: clk-periph: Add save and restore support | From | Sowjanya Komatineni <> | Date | Fri, 2 Aug 2019 13:32:06 -0700 |
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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 >>>>>>>>> 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.
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