09.08.2019 14:55, Dmitry Osipenko пишет:
> 09.08.2019 2:46, Sowjanya Komatineni пишет:
>> This patch implements restore_context support for clk-periph and
>> clk-sdmmc-mux clock operations to restore clock parent and rates
>> on system resume.
>>
>> During system suspend, core power goes off and looses the context
>> of the Tegra clock controller registers.
>>
>> So on system resume, clocks parent and rate are restored back to
>> the context before suspend based on cached data.
>>
>> Signed-off-by: Sowjanya Komatineni <skomatineni@xxxxxxxxxx>
>> ---
>> drivers/clk/tegra/clk-periph.c | 18 ++++++++++++++++++
>> drivers/clk/tegra/clk-sdmmc-mux.c | 12 ++++++++++++
>> 2 files changed, 30 insertions(+)
>>
>> diff --git a/drivers/clk/tegra/clk-periph.c b/drivers/clk/tegra/clk-periph.c
>> index 58437da25156..c9d28cbadccc 100644
>> --- a/drivers/clk/tegra/clk-periph.c
>> +++ b/drivers/clk/tegra/clk-periph.c
>> @@ -3,6 +3,7 @@
>> * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
>> */
>>
>> +#include <linux/clk.h>
>> #include <linux/clk-provider.h>
>> #include <linux/export.h>
>> #include <linux/slab.h>
>> @@ -99,6 +100,20 @@ static void clk_periph_disable(struct clk_hw *hw)
>> gate_ops->disable(gate_hw);
>> }
>>
>> +static void clk_periph_restore_context(struct clk_hw *hw)
>> +{
>> + struct tegra_clk_periph *periph = to_clk_periph(hw);
>> + const struct clk_ops *div_ops = periph->div_ops;
>> + struct clk_hw *div_hw = &periph->divider.hw;
>> + struct clk_hw *parent = clk_hw_get_parent(hw);
>> + int parent_id = clk_hw_get_parent_index(hw, parent);
>> +
>> + if (!(periph->gate.flags & TEGRA_PERIPH_NO_DIV))
>> + div_ops->restore_context(div_hw);
>> +
>> + clk_periph_set_parent(hw, parent_id);
>> +}
>> +
>> const struct clk_ops tegra_clk_periph_ops = {
>> .get_parent = clk_periph_get_parent,
>> .set_parent = clk_periph_set_parent,
>> @@ -108,6 +123,7 @@ const struct clk_ops tegra_clk_periph_ops = {
>> .is_enabled = clk_periph_is_enabled,
>> .enable = clk_periph_enable,
>> .disable = clk_periph_disable,
>> + .restore_context = clk_periph_restore_context,
>> };
>>
>> static const struct clk_ops tegra_clk_periph_nodiv_ops = {
>> @@ -116,6 +132,7 @@ static const struct clk_ops tegra_clk_periph_nodiv_ops = {
>> .is_enabled = clk_periph_is_enabled,
>> .enable = clk_periph_enable,
>> .disable = clk_periph_disable,
>> + .restore_context = clk_periph_restore_context,
>> };
>>
>> static const struct clk_ops tegra_clk_periph_no_gate_ops = {
>> @@ -124,6 +141,7 @@ static const struct clk_ops tegra_clk_periph_no_gate_ops = {
>> .recalc_rate = clk_periph_recalc_rate,
>> .round_rate = clk_periph_round_rate,
>> .set_rate = clk_periph_set_rate,
>> + .restore_context = clk_periph_restore_context,
>> };
>>
>> static struct clk *_tegra_clk_register_periph(const char *name,
>> diff --git a/drivers/clk/tegra/clk-sdmmc-mux.c b/drivers/clk/tegra/clk-sdmmc-mux.c
>> index a5cd3e31dbae..8db48966b100 100644
>> --- a/drivers/clk/tegra/clk-sdmmc-mux.c
>> +++ b/drivers/clk/tegra/clk-sdmmc-mux.c
>> @@ -194,6 +194,17 @@ static void clk_sdmmc_mux_disable(struct clk_hw *hw)
>> gate_ops->disable(gate_hw);
>> }
>>
>> +static void clk_sdmmc_mux_restore_context(struct clk_hw *hw)
>> +{
>> + struct clk_hw *parent = clk_hw_get_parent(hw);
>> + unsigned long parent_rate = clk_hw_get_rate(parent);
>> + unsigned long rate = clk_hw_get_rate(hw);
>> + int parent_id = clk_hw_get_parent_index(hw, parent);
>> +
>> + clk_sdmmc_mux_set_parent(hw, parent_id);
>> + clk_sdmmc_mux_set_rate(hw, rate, parent_rate);
>
> For the periph clocks you're restoring rate at first and then the
> parent, while here it's the other way around. I'm wondering if there is
> any difference in practice and thus whether rate's divider need to be
> set to a some safe value before switching to a new parent that has a
> higher clock rate than the old parent.
Although, I guess that all peripheral clocks should be disabled at this
point of resume. Correct?
>> +}
>> +
>> static const struct clk_ops tegra_clk_sdmmc_mux_ops = {
>> .get_parent = clk_sdmmc_mux_get_parent,
>> .set_parent = clk_sdmmc_mux_set_parent,
>> @@ -203,6 +214,7 @@ static const struct clk_ops tegra_clk_sdmmc_mux_ops = {
>> .is_enabled = clk_sdmmc_mux_is_enabled,
>> .enable = clk_sdmmc_mux_enable,
>> .disable = clk_sdmmc_mux_disable,
>> + .restore_context = clk_sdmmc_mux_restore_context,
>> };
>>
>> struct clk *tegra_clk_register_sdmmc_mux_div(const char *name,
>>
>
