[v8,08/21] clk: tegra: periph: Add restore_context support
diff mbox series

Message ID 1565308020-31952-9-git-send-email-skomatineni@nvidia.com
State New
Headers show
Series
  • SC7 entry and exit support for Tegra210
Related show

Commit Message

Sowjanya Komatineni Aug. 8, 2019, 11:46 p.m. UTC
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@nvidia.com>
---
 drivers/clk/tegra/clk-periph.c    | 18 ++++++++++++++++++
 drivers/clk/tegra/clk-sdmmc-mux.c | 12 ++++++++++++
 2 files changed, 30 insertions(+)

Comments

Dmitry Osipenko Aug. 9, 2019, 11:55 a.m. UTC | #1
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@nvidia.com>
> ---
>  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.

> +}
> +
>  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,
>
Dmitry Osipenko Aug. 9, 2019, 12:20 p.m. UTC | #2
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@nvidia.com>
>> ---
>>  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,
>>
>
Sowjanya Komatineni Aug. 9, 2019, 4:55 p.m. UTC | #3
On 8/9/19 5:20 AM, Dmitry Osipenko wrote:
> 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@nvidia.com>
>>> ---
>>>   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?

by the time restore happens, peripheral clocks are enabled but held in 
reset state.

For non-boot clocks, doing divider programming before parent source is 
preferred.

For sdmmc clock, programming parent before divisor is allowed.

Also, clk_sdmmc_mux_set_rate gets parent MUX selection thru register 
read so restoring parent prior to this will have right divisor based on 
rate and parent.

>>> +}
>>> +
>>>   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,
>>>
Thierry Reding Aug. 12, 2019, 9:50 a.m. UTC | #4
On Thu, Aug 08, 2019 at 04:46:47PM -0700, Sowjanya Komatineni wrote:
> 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@nvidia.com>
> ---
>  drivers/clk/tegra/clk-periph.c    | 18 ++++++++++++++++++
>  drivers/clk/tegra/clk-sdmmc-mux.c | 12 ++++++++++++
>  2 files changed, 30 insertions(+)

Acked-by: Thierry Reding <treding@nvidia.com>

Patch
diff mbox series

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);
+}
+
 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,