[PATCH V3 1/2] firmware: arm_scmi: Implement Clock get permissions

[PATCH V3 1/2] firmware: arm_scmi: Implement Clock get permissions

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@nxp.com>

ARM SCMI Spec 3.2 introduces Clock Get Permission command. This patch
is to add the support. Add three bool entries to scmi_clock_info to
indicate the operation is forbidden or not. If the CLOCK_GET_PERMISSIONS
command is not supported, the three bool variables will default
set to false, otherwise they will be set according to the return result
of CLOCK_GET_PERMISSIONS.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---

V3:
 Rebased on https://lore.kernel.org/linux-arm-kernel/20240110120916.2482603-1-cristian.marussi@arm.com/
 Drop attribute which is no needed
 Use scmi_clock_domain_lookup
 Update patch subject

V2:
 Take Cristian's suggestion, https://lore.kernel.org/all/ZWiqqfQ73tezFmSk@pluto/

 drivers/firmware/arm_scmi/clock.c | 64 +++++++++++++++++++++++++++++++
 include/linux/scmi_protocol.h     |  3 ++
 2 files changed, 67 insertions(+)

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 2e4d6479a639..959e48aba1b5 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -28,8 +28,13 @@ enum scmi_clock_protocol_cmd {
 	CLOCK_POSSIBLE_PARENTS_GET = 0xC,
 	CLOCK_PARENT_SET = 0xD,
 	CLOCK_PARENT_GET = 0xE,
+	CLOCK_GET_PERMISSIONS = 0xF,
 };
 
+#define CLOCK_STATE_CONTROL_ALLOWED	BIT(31)
+#define CLOCK_PARENT_CONTROL_ALLOWED	BIT(30)
+#define CLOCK_RATE_CONTROL_ALLOWED	BIT(29)
+
 enum clk_state {
 	CLK_STATE_DISABLE,
 	CLK_STATE_ENABLE,
@@ -49,6 +54,7 @@ struct scmi_msg_resp_clock_attributes {
 #define SUPPORTS_RATE_CHANGE_REQUESTED_NOTIF(x)	((x) & BIT(30))
 #define SUPPORTS_EXTENDED_NAMES(x)		((x) & BIT(29))
 #define SUPPORTS_PARENT_CLOCK(x)		((x) & BIT(28))
+#define SUPPORTS_GET_PERMISSIONS(x)		((x) & BIT(1))
 	u8 name[SCMI_SHORT_NAME_MAX_SIZE];
 	__le32 clock_enable_latency;
 };
@@ -293,6 +299,35 @@ static int scmi_clock_possible_parents(const struct scmi_protocol_handle *ph, u3
 	return ret;
 }
 
+static int
+scmi_clock_get_permissions(const struct scmi_protocol_handle *ph, u32 clk_id,
+			   struct scmi_clock_info *clk)
+{
+	struct scmi_xfer *t;
+	u32 perm;
+	int ret;
+
+	ret = ph->xops->xfer_get_init(ph, CLOCK_GET_PERMISSIONS,
+				      sizeof(clk_id), sizeof(perm), &t);
+	if (ret)
+		return ret;
+
+	put_unaligned_le32(clk_id, t->tx.buf);
+
+	ret = ph->xops->do_xfer(ph, t);
+	if (!ret) {
+		perm = get_unaligned_le32(t->rx.buf);
+
+		clk->state_ctrl_forbidden = !(perm & CLOCK_STATE_CONTROL_ALLOWED);
+		clk->rate_ctrl_forbidden = !(perm & CLOCK_RATE_CONTROL_ALLOWED);
+		clk->parent_ctrl_forbidden = !(perm & CLOCK_PARENT_CONTROL_ALLOWED);
+	}
+
+	ph->xops->xfer_put(ph, t);
+
+	return ret;
+}
+
 static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
 				     u32 clk_id, struct scmi_clock_info *clk,
 				     u32 version)
@@ -339,6 +374,8 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
 			clk->rate_change_requested_notifications = true;
 		if (SUPPORTS_PARENT_CLOCK(attributes))
 			scmi_clock_possible_parents(ph, clk_id, clk);
+		if (SUPPORTS_GET_PERMISSIONS(attributes))
+			scmi_clock_get_permissions(ph, clk_id, clk);
 	}
 
 	return ret;
@@ -511,6 +548,14 @@ static int scmi_clock_rate_set(const struct scmi_protocol_handle *ph,
 	struct scmi_xfer *t;
 	struct scmi_clock_set_rate *cfg;
 	struct clock_info *ci = ph->get_priv(ph);
+	struct scmi_clock_info *clk;
+
+	clk = scmi_clock_domain_lookup(ci, clk_id);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	if (clk->rate_ctrl_forbidden)
+		return -EACCES;
 
 	ret = ph->xops->xfer_get_init(ph, CLOCK_RATE_SET, sizeof(*cfg), 0, &t);
 	if (ret)
@@ -596,6 +641,9 @@ scmi_clock_set_parent(const struct scmi_protocol_handle *ph, u32 clk_id,
 	if (parent_id >= clk->num_parents)
 		return -EINVAL;
 
+	if (clk->parent_ctrl_forbidden)
+		return -EACCES;
+
 	ret = ph->xops->xfer_get_init(ph, CLOCK_PARENT_SET,
 				      sizeof(*cfg), 0, &t);
 	if (ret)
@@ -679,6 +727,14 @@ static int scmi_clock_enable(const struct scmi_protocol_handle *ph, u32 clk_id,
 			     bool atomic)
 {
 	struct clock_info *ci = ph->get_priv(ph);
+	struct scmi_clock_info *clk;
+
+	clk = scmi_clock_domain_lookup(ci, clk_id);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	if (clk->state_ctrl_forbidden)
+		return -EACCES;
 
 	return ci->clock_config_set(ph, clk_id, CLK_STATE_ENABLE,
 				    NULL_OEM_TYPE, 0, atomic);
@@ -688,6 +744,14 @@ static int scmi_clock_disable(const struct scmi_protocol_handle *ph, u32 clk_id,
 			      bool atomic)
 {
 	struct clock_info *ci = ph->get_priv(ph);
+	struct scmi_clock_info *clk;
+
+	clk = scmi_clock_domain_lookup(ci, clk_id);
+	if (IS_ERR(clk))
+		return PTR_ERR(clk);
+
+	if (clk->state_ctrl_forbidden)
+		return -EACCES;
 
 	return ci->clock_config_set(ph, clk_id, CLK_STATE_DISABLE,
 				    NULL_OEM_TYPE, 0, atomic);
diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index f2f05fb42d28..0cc40af5519a 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -47,6 +47,9 @@ struct scmi_clock_info {
 	bool rate_discrete;
 	bool rate_changed_notifications;
 	bool rate_change_requested_notifications;
+	bool state_ctrl_forbidden;
+	bool rate_ctrl_forbidden;
+	bool parent_ctrl_forbidden;
 	union {
 		struct {
 			int num_rates;
-- 
2.37.1


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[PATCH V3 2/2] clk: scmi: support state_ctrl_forbidden

[Peng Fan (OSS)]

From: Peng Fan <peng.fan@nxp.com>

Some clocks may exported to linux, while those clocks are not allowed
to configure by Linux. For example:

SYS_CLK1-----
             \
	     --MUX--->MMC1_CLK
             /
SYS_CLK2-----

MMC1 needs set parent, so SYS_CLK1 and SYS_CLK2 are exported to Linux,
then the clk propagation will touch SYS_CLK1 or SYS_CLK2.
So we need bypass the failure for SYS_CLK1 or SYS_CLK2 when enable
the clock of MMC1.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---

V3:
 Add check in atomic enable

V2:
 New. Take Cristian's suggestion

 drivers/clk/clk-scmi.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index 8cbe24789c24..5327e0547741 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -119,8 +119,13 @@ static int scmi_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *r
 static int scmi_clk_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);
+	int ret;
+
+	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
+	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
+		return 0;
 
-	return scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
+	return ret;
 }
 
 static void scmi_clk_disable(struct clk_hw *hw)
@@ -133,8 +138,13 @@ static void scmi_clk_disable(struct clk_hw *hw)
 static int scmi_clk_atomic_enable(struct clk_hw *hw)
 {
 	struct scmi_clk *clk = to_scmi_clk(hw);
+	int ret;
+
+	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
+	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
+		return 0;
 
-	return scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
+	return ret;
 }
 
 static void scmi_clk_atomic_disable(struct clk_hw *hw)
-- 
2.37.1


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Re: [PATCH V3 2/2] clk: scmi: support state_ctrl_forbidden

[Cristian Marussi]

On Mon, Jan 15, 2024 at 02:02:03PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> Some clocks may exported to linux, while those clocks are not allowed
> to configure by Linux. For example:
> 
> SYS_CLK1-----
>              \
> 	     --MUX--->MMC1_CLK
>              /
> SYS_CLK2-----
> 
> MMC1 needs set parent, so SYS_CLK1 and SYS_CLK2 are exported to Linux,
> then the clk propagation will touch SYS_CLK1 or SYS_CLK2.
> So we need bypass the failure for SYS_CLK1 or SYS_CLK2 when enable
> the clock of MMC1.
> 

Hi,

so this looks good to me and apparently (as noted) the CLK framework is OK
with a driver swallowing the -EACCESS when a clock is immutable, BUT at the
end of the day do we even need to try this SCMI call and hide the failure in
case of immutable clocks ?

I mean, what if we just dont provide any callback for enable/disable...I can
see plenty of drivers not providing those callbacks ?
Maybe this is probably more of a question for Stephen...

IOW what about doing something like below...does it make any difference
in your setup ? works fine in my emulated env

(Note that last snippet in clk_gate_restore_context() is probably a fix
 that needs to be added anyway by looking at the code in clk.c)

Thanks,
Cristian

--->8----
diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
index 5327e0547741..a669a2f2f78b 100644
--- a/drivers/clk/clk-scmi.c
+++ b/drivers/clk/clk-scmi.c
@@ -121,11 +121,7 @@ static int scmi_clk_enable(struct clk_hw *hw)
 	struct scmi_clk *clk = to_scmi_clk(hw);
 	int ret;
 
-	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
-	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
-		return 0;
-
-	return ret;
+	return scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
 }
 
 static void scmi_clk_disable(struct clk_hw *hw)
@@ -140,11 +136,7 @@ static int scmi_clk_atomic_enable(struct clk_hw *hw)
 	struct scmi_clk *clk = to_scmi_clk(hw);
 	int ret;
 
-	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
-	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
-		return 0;
-
-	return ret;
+	return scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
 }
 
 static void scmi_clk_atomic_disable(struct clk_hw *hw)
@@ -204,6 +196,15 @@ static const struct clk_ops scmi_atomic_clk_ops = {
 	.determine_rate = scmi_clk_determine_rate,
 };
 
+static const struct clk_ops scmi_no_state_ctrl_clk_ops = {
+	.recalc_rate = scmi_clk_recalc_rate,
+	.round_rate = scmi_clk_round_rate,
+	.set_rate = scmi_clk_set_rate,
+	.set_parent = scmi_clk_set_parent,
+	.get_parent = scmi_clk_get_parent,
+	.determine_rate = scmi_clk_determine_rate,
+};
+
 static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
 			     const struct clk_ops *scmi_ops)
 {
@@ -300,8 +301,10 @@ static int scmi_clocks_probe(struct scmi_device *sdev)
 		 * specify (or support) an enable_latency associated with a
 		 * clock, we default to use atomic operations mode.
 		 */
-		if (is_atomic &&
-		    sclk->info->enable_latency <= atomic_threshold)
+		if (sclk->info->state_ctrl_forbidden)
+			scmi_ops = &scmi_no_state_ctrl_clk_ops;
+		else if (is_atomic &&
+			 sclk->info->enable_latency <= atomic_threshold)
 			scmi_ops = &scmi_atomic_clk_ops;
 		else
 			scmi_ops = &scmi_clk_ops;
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f0940af485a5..79b90a8099d7 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1200,9 +1200,11 @@ void clk_gate_restore_context(struct clk_hw *hw)
 	struct clk_core *core = hw->core;
 
 	if (core->enable_count)
-		core->ops->enable(hw);
+		if (core->ops->enable)
+			core->ops->enable(hw);
 	else
-		core->ops->disable(hw);
+		if (core->ops->disable)
+			core->ops->disable(hw);
 }
 EXPORT_SYMBOL_GPL(clk_gate_restore_context);
---8<---

> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
> 
> V3:
>  Add check in atomic enable
> 
> V2:
>  New. Take Cristian's suggestion
> 
>  drivers/clk/clk-scmi.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> index 8cbe24789c24..5327e0547741 100644
> --- a/drivers/clk/clk-scmi.c
> +++ b/drivers/clk/clk-scmi.c
> @@ -119,8 +119,13 @@ static int scmi_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *r
>  static int scmi_clk_enable(struct clk_hw *hw)
>  {
>  	struct scmi_clk *clk = to_scmi_clk(hw);
> +	int ret;
> +
> +	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
> +	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
> +		return 0;
>  
> -	return scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
> +	return ret;
>  }
>  
>  static void scmi_clk_disable(struct clk_hw *hw)
> @@ -133,8 +138,13 @@ static void scmi_clk_disable(struct clk_hw *hw)
>  static int scmi_clk_atomic_enable(struct clk_hw *hw)
>  {
>  	struct scmi_clk *clk = to_scmi_clk(hw);
> +	int ret;
> +
> +	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
> +	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
> +		return 0;
>  
> -	return scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
> +	return ret;
>  }
>  
>  static void scmi_clk_atomic_disable(struct clk_hw *hw)
> -- 
> 2.37.1
> 

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Re: [PATCH V3 2/2] clk: scmi: support state_ctrl_forbidden

[Peng Fan]

在 1/19/2024 2:27 AM, Cristian Marussi 写道:
> On Mon, Jan 15, 2024 at 02:02:03PM +0800, Peng Fan (OSS) wrote:
>> From: Peng Fan <peng.fan@nxp.com>
>>
>> Some clocks may exported to linux, while those clocks are not allowed
>> to configure by Linux. For example:
>>
>> SYS_CLK1-----
>>               \
>> 	     --MUX--->MMC1_CLK
>>               /
>> SYS_CLK2-----
>>
>> MMC1 needs set parent, so SYS_CLK1 and SYS_CLK2 are exported to Linux,
>> then the clk propagation will touch SYS_CLK1 or SYS_CLK2.
>> So we need bypass the failure for SYS_CLK1 or SYS_CLK2 when enable
>> the clock of MMC1.
>>
> 
> Hi,
> 
> so this looks good to me and apparently (as noted) the CLK framework is OK
> with a driver swallowing the -EACCESS when a clock is immutable, BUT at the
> end of the day do we even need to try this SCMI call and hide the failure in
> case of immutable clocks ?
> 
> I mean, what if we just dont provide any callback for enable/disable...I can
> see plenty of drivers not providing those callbacks ?
> Maybe this is probably more of a question for Stephen...
> 
> IOW what about doing something like below...does it make any difference
> in your setup ? works fine in my emulated env

It should be fine to use your changes. Do you expect me to use your 
patch or make it as a follow up patch?

> 
> (Note that last snippet in clk_gate_restore_context() is probably a fix
>   that needs to be added anyway by looking at the code in clk.c)

This API seems only used by TI gate driver, this change should be in a
standalone change go through clk tree. So I would your changes
as a standalone optimization follow up patch, while not included
in my patchset.

THanks,
Peng.

> 
> Thanks,
> Cristian
> 
> --->8----
> diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
> index 5327e0547741..a669a2f2f78b 100644
> --- a/drivers/clk/clk-scmi.c
> +++ b/drivers/clk/clk-scmi.c
> @@ -121,11 +121,7 @@ static int scmi_clk_enable(struct clk_hw *hw)
>   	struct scmi_clk *clk = to_scmi_clk(hw);
>   	int ret;
>   
> -	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
> -	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
> -		return 0;
> -
> -	return ret;
> +	return scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
>   }
>   
>   static void scmi_clk_disable(struct clk_hw *hw)
> @@ -140,11 +136,7 @@ static int scmi_clk_atomic_enable(struct clk_hw *hw)
>   	struct scmi_clk *clk = to_scmi_clk(hw);
>   	int ret;
>   
> -	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
> -	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
> -		return 0;
> -
> -	return ret;
> +	return scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
>   }
>   
>   static void scmi_clk_atomic_disable(struct clk_hw *hw)
> @@ -204,6 +196,15 @@ static const struct clk_ops scmi_atomic_clk_ops = {
>   	.determine_rate = scmi_clk_determine_rate,
>   };
>   
> +static const struct clk_ops scmi_no_state_ctrl_clk_ops = {
> +	.recalc_rate = scmi_clk_recalc_rate,
> +	.round_rate = scmi_clk_round_rate,
> +	.set_rate = scmi_clk_set_rate,
> +	.set_parent = scmi_clk_set_parent,
> +	.get_parent = scmi_clk_get_parent,
> +	.determine_rate = scmi_clk_determine_rate,
> +};
> +
>   static int scmi_clk_ops_init(struct device *dev, struct scmi_clk *sclk,
>   			     const struct clk_ops *scmi_ops)
>   {
> @@ -300,8 +301,10 @@ static int scmi_clocks_probe(struct scmi_device *sdev)
>   		 * specify (or support) an enable_latency associated with a
>   		 * clock, we default to use atomic operations mode.
>   		 */
> -		if (is_atomic &&
> -		    sclk->info->enable_latency <= atomic_threshold)
> +		if (sclk->info->state_ctrl_forbidden)
> +			scmi_ops = &scmi_no_state_ctrl_clk_ops;
> +		else if (is_atomic &&
> +			 sclk->info->enable_latency <= atomic_threshold)
>   			scmi_ops = &scmi_atomic_clk_ops;
>   		else
>   			scmi_ops = &scmi_clk_ops;
> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index f0940af485a5..79b90a8099d7 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -1200,9 +1200,11 @@ void clk_gate_restore_context(struct clk_hw *hw)
>   	struct clk_core *core = hw->core;
>   
>   	if (core->enable_count)
> -		core->ops->enable(hw);
> +		if (core->ops->enable)
> +			core->ops->enable(hw);
>   	else
> -		core->ops->disable(hw);
> +		if (core->ops->disable)
> +			core->ops->disable(hw);
>   }
>   EXPORT_SYMBOL_GPL(clk_gate_restore_context);
> ---8<---
> 
>> Signed-off-by: Peng Fan <peng.fan@nxp.com>
>> ---
>>
>> V3:
>>   Add check in atomic enable
>>
>> V2:
>>   New. Take Cristian's suggestion
>>
>>   drivers/clk/clk-scmi.c | 14 ++++++++++++--
>>   1 file changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/clk/clk-scmi.c b/drivers/clk/clk-scmi.c
>> index 8cbe24789c24..5327e0547741 100644
>> --- a/drivers/clk/clk-scmi.c
>> +++ b/drivers/clk/clk-scmi.c
>> @@ -119,8 +119,13 @@ static int scmi_clk_determine_rate(struct clk_hw *hw, struct clk_rate_request *r
>>   static int scmi_clk_enable(struct clk_hw *hw)
>>   {
>>   	struct scmi_clk *clk = to_scmi_clk(hw);
>> +	int ret;
>> +
>> +	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
>> +	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
>> +		return 0;
>>   
>> -	return scmi_proto_clk_ops->enable(clk->ph, clk->id, NOT_ATOMIC);
>> +	return ret;
>>   }
>>   
>>   static void scmi_clk_disable(struct clk_hw *hw)
>> @@ -133,8 +138,13 @@ static void scmi_clk_disable(struct clk_hw *hw)
>>   static int scmi_clk_atomic_enable(struct clk_hw *hw)
>>   {
>>   	struct scmi_clk *clk = to_scmi_clk(hw);
>> +	int ret;
>> +
>> +	ret = scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
>> +	if (ret == -EACCES && clk->info->state_ctrl_forbidden)
>> +		return 0;
>>   
>> -	return scmi_proto_clk_ops->enable(clk->ph, clk->id, ATOMIC);
>> +	return ret;
>>   }
>>   
>>   static void scmi_clk_atomic_disable(struct clk_hw *hw)
>> -- 
>> 2.37.1
>>

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Re: [PATCH V3 2/2] clk: scmi: support state_ctrl_forbidden

[Cristian Marussi]

On Sat, Jan 20, 2024 at 10:44:06AM +0800, Peng Fan wrote:
> 
> 
> 在 1/19/2024 2:27 AM, Cristian Marussi 写道:
> > On Mon, Jan 15, 2024 at 02:02:03PM +0800, Peng Fan (OSS) wrote:
> > > From: Peng Fan <peng.fan@nxp.com>
> > > 
> > > Some clocks may exported to linux, while those clocks are not allowed
> > > to configure by Linux. For example:
> > > 
> > > SYS_CLK1-----
> > >               \
> > > 	     --MUX--->MMC1_CLK
> > >               /
> > > SYS_CLK2-----
> > > 
> > > MMC1 needs set parent, so SYS_CLK1 and SYS_CLK2 are exported to Linux,
> > > then the clk propagation will touch SYS_CLK1 or SYS_CLK2.
> > > So we need bypass the failure for SYS_CLK1 or SYS_CLK2 when enable
> > > the clock of MMC1.
> > > 
> > 
> > Hi,
> > 
> > so this looks good to me and apparently (as noted) the CLK framework is OK
> > with a driver swallowing the -EACCESS when a clock is immutable, BUT at the
> > end of the day do we even need to try this SCMI call and hide the failure in
> > case of immutable clocks ?
> > 
> > I mean, what if we just dont provide any callback for enable/disable...I can
> > see plenty of drivers not providing those callbacks ?
> > Maybe this is probably more of a question for Stephen...
> > 
> > IOW what about doing something like below...does it make any difference
> > in your setup ? works fine in my emulated env
> 
> It should be fine to use your changes. Do you expect me to use your patch or
> make it as a follow up patch?
> 

It was just a suggestion, if you think is fine just include it in your
series, I dont mind.

> > 
> > (Note that last snippet in clk_gate_restore_context() is probably a fix
> >   that needs to be added anyway by looking at the code in clk.c)
> 
> This API seems only used by TI gate driver, this change should be in a
> standalone change go through clk tree. So I would your changes
> as a standalone optimization follow up patch, while not included
> in my patchset.

Yes, indeed I have made a small patch of it to post it separately..and I
forgot :D... sending it now.

Thanks,
Cristian

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Re: [PATCH V3 1/2] firmware: arm_scmi: Implement Clock get permissions

[Cristian Marussi]

On Mon, Jan 15, 2024 at 02:02:02PM +0800, Peng Fan (OSS) wrote:
> From: Peng Fan <peng.fan@nxp.com>
> 
> ARM SCMI Spec 3.2 introduces Clock Get Permission command. This patch
> is to add the support. Add three bool entries to scmi_clock_info to
> indicate the operation is forbidden or not. If the CLOCK_GET_PERMISSIONS
> command is not supported, the three bool variables will default
> set to false, otherwise they will be set according to the return result
> of CLOCK_GET_PERMISSIONS.
> 

LGTM.

Reviewed-by: Cristian Marussi <cristian.marussi@arm.com>

Thanks,
Cristian

> Signed-off-by: Peng Fan <peng.fan@nxp.com>
> ---
> 
> V3:
>  Rebased on https://lore.kernel.org/linux-arm-kernel/20240110120916.2482603-1-cristian.marussi@arm.com/
>  Drop attribute which is no needed
>  Use scmi_clock_domain_lookup
>  Update patch subject
> 
> V2:
>  Take Cristian's suggestion, https://lore.kernel.org/all/ZWiqqfQ73tezFmSk@pluto/
> 
>  drivers/firmware/arm_scmi/clock.c | 64 +++++++++++++++++++++++++++++++
>  include/linux/scmi_protocol.h     |  3 ++
>  2 files changed, 67 insertions(+)
> 
> diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
> index 2e4d6479a639..959e48aba1b5 100644
> --- a/drivers/firmware/arm_scmi/clock.c
> +++ b/drivers/firmware/arm_scmi/clock.c
> @@ -28,8 +28,13 @@ enum scmi_clock_protocol_cmd {
>  	CLOCK_POSSIBLE_PARENTS_GET = 0xC,
>  	CLOCK_PARENT_SET = 0xD,
>  	CLOCK_PARENT_GET = 0xE,
> +	CLOCK_GET_PERMISSIONS = 0xF,
>  };
>  
> +#define CLOCK_STATE_CONTROL_ALLOWED	BIT(31)
> +#define CLOCK_PARENT_CONTROL_ALLOWED	BIT(30)
> +#define CLOCK_RATE_CONTROL_ALLOWED	BIT(29)
> +
>  enum clk_state {
>  	CLK_STATE_DISABLE,
>  	CLK_STATE_ENABLE,
> @@ -49,6 +54,7 @@ struct scmi_msg_resp_clock_attributes {
>  #define SUPPORTS_RATE_CHANGE_REQUESTED_NOTIF(x)	((x) & BIT(30))
>  #define SUPPORTS_EXTENDED_NAMES(x)		((x) & BIT(29))
>  #define SUPPORTS_PARENT_CLOCK(x)		((x) & BIT(28))
> +#define SUPPORTS_GET_PERMISSIONS(x)		((x) & BIT(1))
>  	u8 name[SCMI_SHORT_NAME_MAX_SIZE];
>  	__le32 clock_enable_latency;
>  };
> @@ -293,6 +299,35 @@ static int scmi_clock_possible_parents(const struct scmi_protocol_handle *ph, u3
>  	return ret;
>  }
>  
> +static int
> +scmi_clock_get_permissions(const struct scmi_protocol_handle *ph, u32 clk_id,
> +			   struct scmi_clock_info *clk)
> +{
> +	struct scmi_xfer *t;
> +	u32 perm;
> +	int ret;
> +
> +	ret = ph->xops->xfer_get_init(ph, CLOCK_GET_PERMISSIONS,
> +				      sizeof(clk_id), sizeof(perm), &t);
> +	if (ret)
> +		return ret;
> +
> +	put_unaligned_le32(clk_id, t->tx.buf);
> +
> +	ret = ph->xops->do_xfer(ph, t);
> +	if (!ret) {
> +		perm = get_unaligned_le32(t->rx.buf);
> +
> +		clk->state_ctrl_forbidden = !(perm & CLOCK_STATE_CONTROL_ALLOWED);
> +		clk->rate_ctrl_forbidden = !(perm & CLOCK_RATE_CONTROL_ALLOWED);
> +		clk->parent_ctrl_forbidden = !(perm & CLOCK_PARENT_CONTROL_ALLOWED);
> +	}
> +
> +	ph->xops->xfer_put(ph, t);
> +
> +	return ret;
> +}
> +
>  static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
>  				     u32 clk_id, struct scmi_clock_info *clk,
>  				     u32 version)
> @@ -339,6 +374,8 @@ static int scmi_clock_attributes_get(const struct scmi_protocol_handle *ph,
>  			clk->rate_change_requested_notifications = true;
>  		if (SUPPORTS_PARENT_CLOCK(attributes))
>  			scmi_clock_possible_parents(ph, clk_id, clk);
> +		if (SUPPORTS_GET_PERMISSIONS(attributes))
> +			scmi_clock_get_permissions(ph, clk_id, clk);
>  	}
>  
>  	return ret;
> @@ -511,6 +548,14 @@ static int scmi_clock_rate_set(const struct scmi_protocol_handle *ph,
>  	struct scmi_xfer *t;
>  	struct scmi_clock_set_rate *cfg;
>  	struct clock_info *ci = ph->get_priv(ph);
> +	struct scmi_clock_info *clk;
> +
> +	clk = scmi_clock_domain_lookup(ci, clk_id);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	if (clk->rate_ctrl_forbidden)
> +		return -EACCES;
>  
>  	ret = ph->xops->xfer_get_init(ph, CLOCK_RATE_SET, sizeof(*cfg), 0, &t);
>  	if (ret)
> @@ -596,6 +641,9 @@ scmi_clock_set_parent(const struct scmi_protocol_handle *ph, u32 clk_id,
>  	if (parent_id >= clk->num_parents)
>  		return -EINVAL;
>  
> +	if (clk->parent_ctrl_forbidden)
> +		return -EACCES;
> +
>  	ret = ph->xops->xfer_get_init(ph, CLOCK_PARENT_SET,
>  				      sizeof(*cfg), 0, &t);
>  	if (ret)
> @@ -679,6 +727,14 @@ static int scmi_clock_enable(const struct scmi_protocol_handle *ph, u32 clk_id,
>  			     bool atomic)
>  {
>  	struct clock_info *ci = ph->get_priv(ph);
> +	struct scmi_clock_info *clk;
> +
> +	clk = scmi_clock_domain_lookup(ci, clk_id);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	if (clk->state_ctrl_forbidden)
> +		return -EACCES;
>  
>  	return ci->clock_config_set(ph, clk_id, CLK_STATE_ENABLE,
>  				    NULL_OEM_TYPE, 0, atomic);
> @@ -688,6 +744,14 @@ static int scmi_clock_disable(const struct scmi_protocol_handle *ph, u32 clk_id,
>  			      bool atomic)
>  {
>  	struct clock_info *ci = ph->get_priv(ph);
> +	struct scmi_clock_info *clk;
> +
> +	clk = scmi_clock_domain_lookup(ci, clk_id);
> +	if (IS_ERR(clk))
> +		return PTR_ERR(clk);
> +
> +	if (clk->state_ctrl_forbidden)
> +		return -EACCES;
>  
>  	return ci->clock_config_set(ph, clk_id, CLK_STATE_DISABLE,
>  				    NULL_OEM_TYPE, 0, atomic);
> diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
> index f2f05fb42d28..0cc40af5519a 100644
> --- a/include/linux/scmi_protocol.h
> +++ b/include/linux/scmi_protocol.h
> @@ -47,6 +47,9 @@ struct scmi_clock_info {
>  	bool rate_discrete;
>  	bool rate_changed_notifications;
>  	bool rate_change_requested_notifications;
> +	bool state_ctrl_forbidden;
> +	bool rate_ctrl_forbidden;
> +	bool parent_ctrl_forbidden;
>  	union {
>  		struct {
>  			int num_rates;
> -- 
> 2.37.1
> 

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