Re: [PATCH nouveau 06/11] platform: complete the power up/down sequence

[Vince Hsu]

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@xxxxxxxxxx>
> > ---
> >   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 {

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