Nouveau - Dec 2014 - [PATCH nouveau 06/11] platform: complete the power up/down sequence

Am Dienstag, den 23.12.2014, 18:39 +0800 schrieb Vince
Hsu:
> This patch adds some missing pieces of the rail gaing/ungating sequence
that
> can improve the stability in theory.
> 
> Signed-off-by: Vince Hsu <vinceh at nvidia.com>
> ---
>  drm/nouveau_platform.c | 42 ++++++++++++++++++++++++++++++++++++++++++
>  drm/nouveau_platform.h |  3 +++
>  2 files changed, 45 insertions(+)
> 
> diff --git a/drm/nouveau_platform.c b/drm/nouveau_platform.c
> index 68788b17a45c..527fe2358fc9 100644
> --- a/drm/nouveau_platform.c
> +++ b/drm/nouveau_platform.c
> @@ -25,9 +25,11 @@
>  #include <linux/module.h>
>  #include <linux/platform_device.h>
>  #include <linux/of.h>
> +#include <linux/of_platform.h>
>  #include <linux/reset.h>
>  #include <linux/regulator/consumer.h>
>  #include <soc/tegra/fuse.h>
> +#include <soc/tegra/mc.h>
>  #include <soc/tegra/pmc.h>
>  
>  #include "nouveau_drm.h"
> @@ -61,6 +63,9 @@ static int nouveau_platform_power_up(struct
nouveau_platform_gpu *gpu)
>  	reset_control_deassert(gpu->rst);
>  	udelay(10);
>  
> +	tegra_mc_flush(gpu->mc, gpu->swgroup, false);
> +	udelay(10);
> +
>  	return 0;
>  
>  err_clamp:
> @@ -77,6 +82,14 @@ static int nouveau_platform_power_down(struct
nouveau_platform_gpu *gpu)
>  {
>  	int err;
>  
> +	tegra_mc_flush(gpu->mc, gpu->swgroup, true);
> +	udelay(10);
> +
> +	err = tegra_powergate_gpu_set_clamping(true);
> +	if (err)
> +		return err;
> +	udelay(10);
> +
>  	reset_control_assert(gpu->rst);
>  	udelay(10);
>  
> @@ -91,6 +104,31 @@ static int nouveau_platform_power_down(struct
nouveau_platform_gpu *gpu)
>  	return 0;
>  }
>  
> +static int nouveau_platform_get_mc(struct device *dev,
> +		struct tegra_mc **mc, unsigned int *swgroup)
Uhm, no. If this is needed this has to be a Tegra MC function and not
burried into nouveau code. You are using knowledge about the internal
workings of the MC driver here.

Also this should probably only take the Dt node pointer as argument and
return a something like a tegra_mc_client struct that contains both the
MC device pointer and the swgroup so you can pass that to
tegra_mc_flush().
> +{
> +	struct of_phandle_args args;
> +	struct platform_device *pdev;
> +	int ret;
> +
> +	ret = of_parse_phandle_with_fixed_args(dev->of_node, "mc",
> +				1, 0, &args);
> +	if (ret)
> +		return ret;
> +
> +	pdev = of_find_device_by_node(args.np);
> +	if (!pdev)
> +		return -EINVAL;
This is wrong, you need to handle -EPROBE_DEFER here.
> +
> +	*mc = platform_get_drvdata(pdev);
> +	if (!*mc)
> +		return -EINVAL;
> +
> +	*swgroup = args.args[0];
> +
> +	return 0;
> +}
> +
>  static int nouveau_platform_probe(struct platform_device *pdev)
>  {
>  	struct nouveau_platform_gpu *gpu;
> @@ -118,6 +156,10 @@ static int nouveau_platform_probe(struct
platform_device *pdev)
>  	if (IS_ERR(gpu->clk_pwr))
>  		return PTR_ERR(gpu->clk_pwr);
>  
> +	err = nouveau_platform_get_mc(&pdev->dev, &gpu->mc,
&gpu->swgroup);
> +	if (err)
> +		return err;
> +
>  	err = nouveau_platform_power_up(gpu);
>  	if (err)
>  		return err;
> diff --git a/drm/nouveau_platform.h b/drm/nouveau_platform.h
> index 58c28b5653d5..969dbddd786d 100644
> --- a/drm/nouveau_platform.h
> +++ b/drm/nouveau_platform.h
> @@ -35,6 +35,9 @@ struct nouveau_platform_gpu {
>  	struct clk *clk_pwr;
>  
>  	struct regulator *vdd;
> +
> +	struct tegra_mc *mc;
> +	unsigned int swgroup;
>  };
>  
>  struct nouveau_platform_device {

On 12/24/2014 09:23 PM, Lucas Stach wrote:
> Am Dienstag, den 23.12.2014, 18:39 +0800 schrieb Vince Hsu:
>> This patch adds some missing pieces of the rail gaing/ungating sequence
that
>> can improve the stability in theory.
>>
>> Signed-off-by: Vince Hsu <vinceh at nvidia.com>
>> ---
>>   drm/nouveau_platform.c | 42
++++++++++++++++++++++++++++++++++++++++++
>>   drm/nouveau_platform.h |  3 +++
>>   2 files changed, 45 insertions(+)
>>
>> diff --git a/drm/nouveau_platform.c b/drm/nouveau_platform.c
>> index 68788b17a45c..527fe2358fc9 100644
>> --- a/drm/nouveau_platform.c
>> +++ b/drm/nouveau_platform.c
>> @@ -25,9 +25,11 @@
>>   #include <linux/module.h>
>>   #include <linux/platform_device.h>
>>   #include <linux/of.h>
>> +#include <linux/of_platform.h>
>>   #include <linux/reset.h>
>>   #include <linux/regulator/consumer.h>
>>   #include <soc/tegra/fuse.h>
>> +#include <soc/tegra/mc.h>
>>   #include <soc/tegra/pmc.h>
>>   
>>   #include "nouveau_drm.h"
>> @@ -61,6 +63,9 @@ static int nouveau_platform_power_up(struct
nouveau_platform_gpu *gpu)
>>   	reset_control_deassert(gpu->rst);
>>   	udelay(10);
>>   
>> +	tegra_mc_flush(gpu->mc, gpu->swgroup, false);
>> +	udelay(10);
>> +
>>   	return 0;
>>   
>>   err_clamp:
>> @@ -77,6 +82,14 @@ static int nouveau_platform_power_down(struct
nouveau_platform_gpu *gpu)
>>   {
>>   	int err;
>>   
>> +	tegra_mc_flush(gpu->mc, gpu->swgroup, true);
>> +	udelay(10);
>> +
>> +	err = tegra_powergate_gpu_set_clamping(true);
>> +	if (err)
>> +		return err;
>> +	udelay(10);
>> +
>>   	reset_control_assert(gpu->rst);
>>   	udelay(10);
>>   
>> @@ -91,6 +104,31 @@ static int nouveau_platform_power_down(struct
nouveau_platform_gpu *gpu)
>>   	return 0;
>>   }
>>   
>> +static int nouveau_platform_get_mc(struct device *dev,
>> +		struct tegra_mc **mc, unsigned int *swgroup)
> Uhm, no. If this is needed this has to be a Tegra MC function and not
> burried into nouveau code. You are using knowledge about the internal
> workings of the MC driver here.
>
> Also this should probably only take the Dt node pointer as argument and
> return a something like a tegra_mc_client struct that contains both the
> MC device pointer and the swgroup so you can pass that to
> tegra_mc_flush().
Good idea. I will have something as below in V2 if there is no other 
comments for this.

tegra_mc_client *tegra_mc_find_client(struct device_node *node)
{
     ...
     ret = of_parse_phandle_with_args(node, "nvidia,memory-client",
...)
     ...
}

There were some discussion about this few weeks ago. I'm not sure 
whether we have some conclusion/implementation though. Thierry?

http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/308703.html
>
>> +{
>> +	struct of_phandle_args args;
>> +	struct platform_device *pdev;
>> +	int ret;
>> +
>> +	ret = of_parse_phandle_with_fixed_args(dev->of_node,
"mc",
>> +				1, 0, &args);
>> +	if (ret)
>> +		return ret;
>> +
>> +	pdev = of_find_device_by_node(args.np);
>> +	if (!pdev)
>> +		return -EINVAL;
> This is wrong, you need to handle -EPROBE_DEFER here.
Indeed. Will fix.
>
>> +
>> +	*mc = platform_get_drvdata(pdev);
>> +	if (!*mc)
>> +		return -EINVAL;
>> +
>> +	*swgroup = args.args[0];
>> +
>> +	return 0;
>> +}
>> +
>>   static int nouveau_platform_probe(struct platform_device *pdev)
>>   {
>>   	struct nouveau_platform_gpu *gpu;
>> @@ -118,6 +156,10 @@ static int nouveau_platform_probe(struct
platform_device *pdev)
>>   	if (IS_ERR(gpu->clk_pwr))
>>   		return PTR_ERR(gpu->clk_pwr);
>>   
>> +	err = nouveau_platform_get_mc(&pdev->dev, &gpu->mc,
&gpu->swgroup);
>> +	if (err)
>> +		return err;
>> +
>>   	err = nouveau_platform_power_up(gpu);
>>   	if (err)
>>   		return err;
>> diff --git a/drm/nouveau_platform.h b/drm/nouveau_platform.h
>> index 58c28b5653d5..969dbddd786d 100644
>> --- a/drm/nouveau_platform.h
>> +++ b/drm/nouveau_platform.h
>> @@ -35,6 +35,9 @@ struct nouveau_platform_gpu {
>>   	struct clk *clk_pwr;
>>   
>>   	struct regulator *vdd;
>> +
>> +	struct tegra_mc *mc;
>> +	unsigned int swgroup;
>>   };
>>   
>>   struct nouveau_platform_device {
>

On Thu, Dec 25, 2014 at 10:42:58AM +0800, Vince Hsu
wrote:
> 
> On 12/24/2014 09:23 PM, Lucas Stach wrote:
> >Am Dienstag, den 23.12.2014, 18:39 +0800 schrieb Vince Hsu:
> >>This patch adds some missing pieces of the rail gaing/ungating
sequence that
> >>can improve the stability in theory.
> >>
> >>Signed-off-by: Vince Hsu <vinceh at nvidia.com>
> >>---
> >>  drm/nouveau_platform.c | 42
++++++++++++++++++++++++++++++++++++++++++
> >>  drm/nouveau_platform.h |  3 +++
> >>  2 files changed, 45 insertions(+)
> >>
> >>diff --git a/drm/nouveau_platform.c b/drm/nouveau_platform.c
> >>index 68788b17a45c..527fe2358fc9 100644
> >>--- a/drm/nouveau_platform.c
> >>+++ b/drm/nouveau_platform.c
> >>@@ -25,9 +25,11 @@
> >>  #include <linux/module.h>
> >>  #include <linux/platform_device.h>
> >>  #include <linux/of.h>
> >>+#include <linux/of_platform.h>
> >>  #include <linux/reset.h>
> >>  #include <linux/regulator/consumer.h>
> >>  #include <soc/tegra/fuse.h>
> >>+#include <soc/tegra/mc.h>
> >>  #include <soc/tegra/pmc.h>
> >>  #include "nouveau_drm.h"
> >>@@ -61,6 +63,9 @@ static int nouveau_platform_power_up(struct
nouveau_platform_gpu *gpu)
> >>  	reset_control_deassert(gpu->rst);
> >>  	udelay(10);
> >>+	tegra_mc_flush(gpu->mc, gpu->swgroup, false);
> >>+	udelay(10);
> >>+
> >>  	return 0;
> >>  err_clamp:
> >>@@ -77,6 +82,14 @@ static int nouveau_platform_power_down(struct
nouveau_platform_gpu *gpu)
> >>  {
> >>  	int err;
> >>+	tegra_mc_flush(gpu->mc, gpu->swgroup, true);
> >>+	udelay(10);
> >>+
> >>+	err = tegra_powergate_gpu_set_clamping(true);
> >>+	if (err)
> >>+		return err;
> >>+	udelay(10);
> >>+
> >>  	reset_control_assert(gpu->rst);
> >>  	udelay(10);
> >>@@ -91,6 +104,31 @@ static int nouveau_platform_power_down(struct
nouveau_platform_gpu *gpu)
> >>  	return 0;
> >>  }
> >>+static int nouveau_platform_get_mc(struct device *dev,
> >>+		struct tegra_mc **mc, unsigned int *swgroup)
> >Uhm, no. If this is needed this has to be a Tegra MC function and not
> >burried into nouveau code. You are using knowledge about the internal
> >workings of the MC driver here.
> >
> >Also this should probably only take the Dt node pointer as argument and
> >return a something like a tegra_mc_client struct that contains both the
> >MC device pointer and the swgroup so you can pass that to
> >tegra_mc_flush().
> Good idea. I will have something as below in V2 if there is no other
> comments for this.
> 
> tegra_mc_client *tegra_mc_find_client(struct device_node *node)
> {
>     ...
>     ret = of_parse_phandle_with_args(node,
"nvidia,memory-client", ...)
>     ...
> }
> 
> There were some discussion about this few weeks ago. I'm not sure
whether we
> have some conclusion/implementation though. Thierry?
> 
>
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-December/308703.html
I don't think client is a good fit here. Flushing is done per SWGROUP
(on all clients of the SWGROUP). So I think we'll want something like:

	gpu at 0,57000000 {
		...
		nvidia,swgroup = <&mc TEGRA_SWGROUP_GPU>;
		...
	};

In the DT and return a struct tegra_mc_swgroup along the lines of:

	struct tegra_mc_client {
		unsigned int id;
		unsigned int swgroup;

		struct list_head list;
	};

	struct tegra_mc_swgroup {
		struct list_head clients;
		unsigned int id;
	};

Where tegra_mc_swgroup.clients is a list of struct tegra_mc_client
structures, each representing a memory client pertaining to the
SWGROUP.

We probably don't want to expose these structures publicly, an opaque
type should be enough. Then you can use functions like:

	struct tegra_mc_swgroup *tegra_mc_find_swgroup(struct device_node *node);

At some point we may even need something like:

	struct tegra_mc_client *tegra_mc_find_client(struct device_node *node,
						     const char *name);

And DT content like this:

	gpu at 0,57000000 {
		...
		nvidia,memory-clients = <&mc 0x58>, <&mc 0x59>;
		nvidia,memory-client-names = "read", "write";
		...
	};

This could be useful for latency allowance programming, but we can cross
that bridge when we come to it.

Thierry
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