diff mbox series

[v6,2/6] drm/etnaviv: add a dedicated function to get various clocks

Message ID 20230530160643.2344551-3-suijingfeng@loongson.cn (mailing list archive)
State New, archived
Headers show
Series drm/etnaviv: add pci device driver support | expand

Commit Message

Sui Jingfeng May 30, 2023, 4:06 p.m. UTC 
Because it is also platform-dependent, there are environments where don't
have CLK subsystem support, for example, discreted PCI gpu. So don't rage
quit if there is no CLK subsystem.

For the GPU in LS7a1000 and LS2k2000, the working frequency of the GPU is
tuned by configuring the PLL register directly.

Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 62 ++++++++++++++++++---------
 drivers/gpu/drm/etnaviv/etnaviv_gpu.h |  1 +
 2 files changed, 42 insertions(+), 21 deletions(-)

Comments

Sui Jingfeng June 1, 2023, 10:09 a.m. UTC | #1 
Hi,

On 2023/6/1 02:07, Lucas Stach wrote:
> Am Mittwoch, dem 31.05.2023 um 00:06 +0800 schrieb Sui Jingfeng:
>> Because it is also platform-dependent, there are environments where don't
>> have CLK subsystem support, for example, discreted PCI gpu. So don't rage
>> quit if there is no CLK subsystem.
>>
>> For the GPU in LS7a1000 and LS2k2000, the working frequency of the GPU is
>> tuned by configuring the PLL register directly.
>>
> Is this PLL under control of system firmware and invisible to Linux?
Yes, it is registers, both system firmware and kernel space driver can 
access it.
>> Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
>> ---
>>   drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 62 ++++++++++++++++++---------
>>   drivers/gpu/drm/etnaviv/etnaviv_gpu.h |  1 +
>>   2 files changed, 42 insertions(+), 21 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
>> index 636d3f39ddcb..4937580551a5 100644
>> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
>> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
>> @@ -1565,10 +1565,45 @@ static irqreturn_t irq_handler(int irq, void *data)
>>   	return ret;
>>   }
>>   
>> +static int etnaviv_gpu_clk_get(struct etnaviv_gpu *gpu)
>> +{
>> +	struct device *dev = gpu->dev;
>> +
>> +	if (gpu->no_clk)
>> +		return 0;
>> +
>> +	gpu->clk_reg = devm_clk_get_optional(dev, "reg");
>> +	DBG("clk_reg: %p", gpu->clk_reg);
>> +	if (IS_ERR(gpu->clk_reg))
>> +		return PTR_ERR(gpu->clk_reg);
>> +
>> +	gpu->clk_bus = devm_clk_get_optional(dev, "bus");
>> +	DBG("clk_bus: %p", gpu->clk_bus);
>> +	if (IS_ERR(gpu->clk_bus))
>> +		return PTR_ERR(gpu->clk_bus);
>> +
>> +	gpu->clk_core = devm_clk_get(dev, "core");
>> +	DBG("clk_core: %p", gpu->clk_core);
>> +	if (IS_ERR(gpu->clk_core))
>> +		return PTR_ERR(gpu->clk_core);
>> +	gpu->base_rate_core = clk_get_rate(gpu->clk_core);
>> +
>> +	gpu->clk_shader = devm_clk_get_optional(dev, "shader");
>> +	DBG("clk_shader: %p", gpu->clk_shader);
>> +	if (IS_ERR(gpu->clk_shader))
>> +		return PTR_ERR(gpu->clk_shader);
>> +	gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
>> +
>> +	return 0;
>> +}
>> +
>>   static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
>>   {
>>   	int ret;
>>   
>> +	if (gpu->no_clk)
>> +		return 0;
>> +
> I don't see why this would be needed? If your platform doesn't provide
> CONFIG_HAVE_CLK all those functions should be successful no-ops, so
> there is no need to special case this in the driver.
>
> Or does your platform in fact provide a clk subsystem, just the GPU
> clocks are managed by it?
>
> Also all those functions are fine with being called on a NULL clk,
right
> so
> shouldn't it be enough to simply avoid calling etnaviv_gpu_clk_get() in
> the PCI device case?

Yes, I just tried, your are right.

There also no need to add the 'no_clk' member into struct etnaviv_gpu

> Regards,
> Lucas
>
>>   	ret = clk_prepare_enable(gpu->clk_reg);
>>   	if (ret)
>>   		return ret;
>> @@ -1599,6 +1634,9 @@ static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
>>   
>>   static int etnaviv_gpu_clk_disable(struct etnaviv_gpu *gpu)
>>   {
>> +	if (gpu->no_clk)
>> +		return 0;
>> +
>>   	clk_disable_unprepare(gpu->clk_shader);
>>   	clk_disable_unprepare(gpu->clk_core);
>>   	clk_disable_unprepare(gpu->clk_bus);
>> @@ -1865,27 +1903,9 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
>>   		return err;
>>   
>>   	/* Get Clocks: */
>> -	gpu->clk_reg = devm_clk_get_optional(&pdev->dev, "reg");
>> -	DBG("clk_reg: %p", gpu->clk_reg);
>> -	if (IS_ERR(gpu->clk_reg))
>> -		return PTR_ERR(gpu->clk_reg);
>> -
>> -	gpu->clk_bus = devm_clk_get_optional(&pdev->dev, "bus");
>> -	DBG("clk_bus: %p", gpu->clk_bus);
>> -	if (IS_ERR(gpu->clk_bus))
>> -		return PTR_ERR(gpu->clk_bus);
>> -
>> -	gpu->clk_core = devm_clk_get(&pdev->dev, "core");
>> -	DBG("clk_core: %p", gpu->clk_core);
>> -	if (IS_ERR(gpu->clk_core))
>> -		return PTR_ERR(gpu->clk_core);
>> -	gpu->base_rate_core = clk_get_rate(gpu->clk_core);
>> -
>> -	gpu->clk_shader = devm_clk_get_optional(&pdev->dev, "shader");
>> -	DBG("clk_shader: %p", gpu->clk_shader);
>> -	if (IS_ERR(gpu->clk_shader))
>> -		return PTR_ERR(gpu->clk_shader);
>> -	gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
>> +	err = etnaviv_gpu_clk_get(gpu);
>> +	if (err)
>> +		return err;
>>   
>>   	/* TODO: figure out max mapped size */
>>   	dev_set_drvdata(dev, gpu);
>> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
>> index 98c6f9c320fc..6da5209a7d64 100644
>> --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
>> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
>> @@ -148,6 +148,7 @@ struct etnaviv_gpu {
>>   	struct clk *clk_reg;
>>   	struct clk *clk_core;
>>   	struct clk *clk_shader;
>> +	bool no_clk;
>>   
>>   	unsigned int freq_scale;
>>   	unsigned long base_rate_core;
Sui Jingfeng June 1, 2023, 1:21 p.m. UTC | #2 
Hi,

On 2023/6/1 02:07, Lucas Stach wrote:
>> +static int etnaviv_gpu_clk_get(struct etnaviv_gpu *gpu)
>> +{
>> +	struct device *dev = gpu->dev;
>> +
>> +	if (gpu->no_clk)
>> +		return 0;
>> +
>> +	gpu->clk_reg = devm_clk_get_optional(dev, "reg");
>> +	DBG("clk_reg: %p", gpu->clk_reg);
>> +	if (IS_ERR(gpu->clk_reg))
>> +		return PTR_ERR(gpu->clk_reg);
>> +
>> +	gpu->clk_bus = devm_clk_get_optional(dev, "bus");
>> +	DBG("clk_bus: %p", gpu->clk_bus);
>> +	if (IS_ERR(gpu->clk_bus))
>> +		return PTR_ERR(gpu->clk_bus);
>> +
>> +	gpu->clk_core = devm_clk_get(dev, "core");
>> +	DBG("clk_core: %p", gpu->clk_core);
>> +	if (IS_ERR(gpu->clk_core))
>> +		return PTR_ERR(gpu->clk_core);
>> +	gpu->base_rate_core = clk_get_rate(gpu->clk_core);
>> +
>> +	gpu->clk_shader = devm_clk_get_optional(dev, "shader");
>> +	DBG("clk_shader: %p", gpu->clk_shader);
>> +	if (IS_ERR(gpu->clk_shader))
>> +		return PTR_ERR(gpu->clk_shader);
>> +	gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
>> +
>> +	return 0;
>> +}
>> +
>>   static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
>>   {
>>   	int ret;
>>   
>> +	if (gpu->no_clk)
>> +		return 0;
>> +
> I don't see why this would be needed?
I have just tested, this do not needed.
> If your platform doesn't provide
> CONFIG_HAVE_CLK all those functions should be successful no-ops, so
> there is no need to special case this in the driver.

My platform do enable CONFIG_HAVE_CLK,

for ls3a5000 + ls7a1000, my system do not provide device tree support,

that's is to say, there is no DT support.


For ls3a4000 + ls7a1000 platform, the system has DT support, but don't 
has CLK drivers implement toward the clock tree.

typically, our platform's firmware will do such thing(setting a default 
working frequency).


When I first saw etnaviv, I'm also astonishing.

I don't know why there so much clock controllable.

As far as I can understand, my system/hardware have only one clock,

It shall corresponding to the core clk.

> Or does your platform in fact provide a clk subsystem, just the GPU
> clocks are managed by it?
>
> Also all those functions are fine with being called on a NULL clk, so
> shouldn't it be enough to simply avoid calling etnaviv_gpu_clk_get() in
> the PCI device case?
>
> Regards,
> Lucas
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 636d3f39ddcb..4937580551a5 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -1565,10 +1565,45 @@  static irqreturn_t irq_handler(int irq, void *data)
 	return ret;
 }
 
+static int etnaviv_gpu_clk_get(struct etnaviv_gpu *gpu)
+{
+	struct device *dev = gpu->dev;
+
+	if (gpu->no_clk)
+		return 0;
+
+	gpu->clk_reg = devm_clk_get_optional(dev, "reg");
+	DBG("clk_reg: %p", gpu->clk_reg);
+	if (IS_ERR(gpu->clk_reg))
+		return PTR_ERR(gpu->clk_reg);
+
+	gpu->clk_bus = devm_clk_get_optional(dev, "bus");
+	DBG("clk_bus: %p", gpu->clk_bus);
+	if (IS_ERR(gpu->clk_bus))
+		return PTR_ERR(gpu->clk_bus);
+
+	gpu->clk_core = devm_clk_get(dev, "core");
+	DBG("clk_core: %p", gpu->clk_core);
+	if (IS_ERR(gpu->clk_core))
+		return PTR_ERR(gpu->clk_core);
+	gpu->base_rate_core = clk_get_rate(gpu->clk_core);
+
+	gpu->clk_shader = devm_clk_get_optional(dev, "shader");
+	DBG("clk_shader: %p", gpu->clk_shader);
+	if (IS_ERR(gpu->clk_shader))
+		return PTR_ERR(gpu->clk_shader);
+	gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
+
+	return 0;
+}
+
 static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
 {
 	int ret;
 
+	if (gpu->no_clk)
+		return 0;
+
 	ret = clk_prepare_enable(gpu->clk_reg);
 	if (ret)
 		return ret;
@@ -1599,6 +1634,9 @@  static int etnaviv_gpu_clk_enable(struct etnaviv_gpu *gpu)
 
 static int etnaviv_gpu_clk_disable(struct etnaviv_gpu *gpu)
 {
+	if (gpu->no_clk)
+		return 0;
+
 	clk_disable_unprepare(gpu->clk_shader);
 	clk_disable_unprepare(gpu->clk_core);
 	clk_disable_unprepare(gpu->clk_bus);
@@ -1865,27 +1903,9 @@  static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
 		return err;
 
 	/* Get Clocks: */
-	gpu->clk_reg = devm_clk_get_optional(&pdev->dev, "reg");
-	DBG("clk_reg: %p", gpu->clk_reg);
-	if (IS_ERR(gpu->clk_reg))
-		return PTR_ERR(gpu->clk_reg);
-
-	gpu->clk_bus = devm_clk_get_optional(&pdev->dev, "bus");
-	DBG("clk_bus: %p", gpu->clk_bus);
-	if (IS_ERR(gpu->clk_bus))
-		return PTR_ERR(gpu->clk_bus);
-
-	gpu->clk_core = devm_clk_get(&pdev->dev, "core");
-	DBG("clk_core: %p", gpu->clk_core);
-	if (IS_ERR(gpu->clk_core))
-		return PTR_ERR(gpu->clk_core);
-	gpu->base_rate_core = clk_get_rate(gpu->clk_core);
-
-	gpu->clk_shader = devm_clk_get_optional(&pdev->dev, "shader");
-	DBG("clk_shader: %p", gpu->clk_shader);
-	if (IS_ERR(gpu->clk_shader))
-		return PTR_ERR(gpu->clk_shader);
-	gpu->base_rate_shader = clk_get_rate(gpu->clk_shader);
+	err = etnaviv_gpu_clk_get(gpu);
+	if (err)
+		return err;
 
 	/* TODO: figure out max mapped size */
 	dev_set_drvdata(dev, gpu);
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
index 98c6f9c320fc..6da5209a7d64 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -148,6 +148,7 @@  struct etnaviv_gpu {
 	struct clk *clk_reg;
 	struct clk *clk_core;
 	struct clk *clk_shader;
+	bool no_clk;
 
 	unsigned int freq_scale;
 	unsigned long base_rate_core;