Re: [PATCH 4/4] drm/tegra: Refactor IOMMU attach/detach

[Thierry Reding <thierry.reding@gmail.com>]

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On Fri, May 04, 2018 at 05:23:42PM +0300, Dmitry Osipenko wrote:
> On 04.05.2018 16:37, Thierry Reding wrote:
> > From: Thierry Reding <treding@nvidia.com>
> > 
> > Attaching to and detaching from an IOMMU uses the same code sequence in
> > every driver, so factor it out into separate helpers.
> > 
> > Signed-off-by: Thierry Reding <treding@nvidia.com>
> > ---
> >  drivers/gpu/drm/tegra/dc.c   | 42 ++++++------------------------------
> >  drivers/gpu/drm/tegra/drm.c  | 42 ++++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/tegra/drm.h  |  4 ++++
> >  drivers/gpu/drm/tegra/gr2d.c | 32 +++++++--------------------
> >  drivers/gpu/drm/tegra/gr3d.c | 31 ++++++--------------------
> >  5 files changed, 68 insertions(+), 83 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
> > index c843f11043db..3e7ec3937346 100644
> > --- a/drivers/gpu/drm/tegra/dc.c
> > +++ b/drivers/gpu/drm/tegra/dc.c
> > @@ -1837,21 +1837,11 @@ static int tegra_dc_init(struct host1x_client *client)
> >  	if (!dc->syncpt)
> >  		dev_warn(dc->dev, "failed to allocate syncpoint\n");
> >  
> > -	if (tegra->domain) {
> > -		dc->group = iommu_group_get(client->dev);
> > -
> > -		if (dc->group && dc->group != tegra->group) {
> > -			err = iommu_attach_group(tegra->domain, dc->group);
> > -			if (err < 0) {
> > -				dev_err(dc->dev,
> > -					"failed to attach to domain: %d\n",
> > -					err);
> > -				iommu_group_put(dc->group);
> > -				return err;
> > -			}
> > -
> > -			tegra->group = dc->group;
> > -		}
> > +	dc->group = host1x_client_iommu_attach(client, true);
> > +	if (IS_ERR(dc->group)) {
> > +		err = PTR_ERR(dc->group);
> > +		dev_err(client->dev, "failed to attach to domain: %d\n", err);
> > +		return err;
> >  	}
> >  
> >  	if (dc->soc->wgrps)
> > @@ -1916,15 +1906,7 @@ static int tegra_dc_init(struct host1x_client *client)
> >  	if (!IS_ERR(primary))
> >  		drm_plane_cleanup(primary);
> >  
> > -	if (dc->group) {
> > -		if (dc->group == tegra->group) {
> > -			iommu_detach_group(tegra->domain, dc->group);
> > -			tegra->group = NULL;
> > -		}
> > -
> > -		iommu_group_put(dc->group);
> > -	}
> > -
> > +	host1x_client_iommu_detach(client, dc->group);
> >  	host1x_syncpt_free(dc->syncpt);
> >  
> >  	return err;
> > @@ -1932,9 +1914,7 @@ static int tegra_dc_init(struct host1x_client *client)
> >  
> >  static int tegra_dc_exit(struct host1x_client *client)
> >  {
> > -	struct drm_device *drm = dev_get_drvdata(client->parent);
> >  	struct tegra_dc *dc = host1x_client_to_dc(client);
> > -	struct tegra_drm *tegra = drm->dev_private;
> >  	int err;
> >  
> >  	devm_free_irq(dc->dev, dc->irq, dc);
> > @@ -1945,15 +1925,7 @@ static int tegra_dc_exit(struct host1x_client *client)
> >  		return err;
> >  	}
> >  
> > -	if (dc->group) {
> > -		if (dc->group == tegra->group) {
> > -			iommu_detach_group(tegra->domain, dc->group);
> > -			tegra->group = NULL;
> > -		}
> > -
> > -		iommu_group_put(dc->group);
> > -	}
> > -
> > +	host1x_client_iommu_detach(client, dc->group);
> >  	host1x_syncpt_free(dc->syncpt);
> >  
> >  	return 0;
> > diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> > index 7afe2f635f74..bc1008305e1e 100644
> > --- a/drivers/gpu/drm/tegra/drm.c
> > +++ b/drivers/gpu/drm/tegra/drm.c
> > @@ -1114,6 +1114,48 @@ int tegra_drm_unregister_client(struct tegra_drm *tegra,
> >  	return 0;
> >  }
> >  
> > +struct iommu_group *host1x_client_iommu_attach(struct host1x_client *client,
> > +					       bool shared)
> > +{
> > +	struct drm_device *drm = dev_get_drvdata(client->parent);
> > +	struct tegra_drm *tegra = drm->dev_private;
> > +	struct iommu_group *group = NULL;
> > +	int err;
> > +
> > +	if (tegra->domain) {
> > +		group = iommu_group_get(client->dev);
> > +
> > +		if (group && (!shared || (shared && (group != tegra->group)))) {
> > +			err = iommu_attach_group(tegra->domain, group);
> > +			if (err < 0) {
> > +				iommu_group_put(group);
> > +				return ERR_PTR(err);
> > +			}
> > +
> > +			if (shared && !tegra->group)
> > +				tegra->group = group;
> > +		}
> > +	}
> > +
> > +	return group;
> > +}
> > +
> > +void host1x_client_iommu_detach(struct host1x_client *client,
> > +				struct iommu_group *group)
> > +{
> > +	struct drm_device *drm = dev_get_drvdata(client->parent);
> > +	struct tegra_drm *tegra = drm->dev_private;
> > +
> > +	if (group) {
> > +		if (group == tegra->group) {
> > +			iommu_detach_group(tegra->domain, group);
> > +			tegra->group = NULL;
> > +		}
> > +
> > +		iommu_group_put(group);
> > +	}
> > +}
> > +
> >  void *tegra_drm_alloc(struct tegra_drm *tegra, size_t size, dma_addr_t *dma)
> >  {
> >  	struct iova *alloc;
> > diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
> > index 4f41aaec8530..fe263cf58f34 100644
> > --- a/drivers/gpu/drm/tegra/drm.h
> > +++ b/drivers/gpu/drm/tegra/drm.h
> > @@ -110,6 +110,10 @@ int tegra_drm_register_client(struct tegra_drm *tegra,
> >  			      struct tegra_drm_client *client);
> >  int tegra_drm_unregister_client(struct tegra_drm *tegra,
> >  				struct tegra_drm_client *client);
> > +struct iommu_group *host1x_client_iommu_attach(struct host1x_client *client,
> > +					       bool shared);
> > +void host1x_client_iommu_detach(struct host1x_client *client,
> > +				struct iommu_group *group);
> >  
> >  int tegra_drm_init(struct tegra_drm *tegra, struct drm_device *drm);
> >  int tegra_drm_exit(struct tegra_drm *tegra);
> > diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
> > index 0b42e99da8ad..2cd0f66c8aa9 100644
> > --- a/drivers/gpu/drm/tegra/gr2d.c
> > +++ b/drivers/gpu/drm/tegra/gr2d.c
> > @@ -32,7 +32,6 @@ static int gr2d_init(struct host1x_client *client)
> >  	struct tegra_drm_client *drm = host1x_to_drm_client(client);
> >  	struct drm_device *dev = dev_get_drvdata(client->parent);
> >  	unsigned long flags = HOST1X_SYNCPT_HAS_BASE;
> > -	struct tegra_drm *tegra = dev->dev_private;
> >  	struct gr2d *gr2d = to_gr2d(drm);
> >  	int err;
> >  
> > @@ -47,22 +46,14 @@ static int gr2d_init(struct host1x_client *client)
> >  		goto put;
> >  	}
> >  
> > -	if (tegra->domain) {
> > -		gr2d->group = iommu_group_get(client->dev);
> > -
> > -		if (gr2d->group) {
> > -			err = iommu_attach_group(tegra->domain, gr2d->group);
> > -			if (err < 0) {
> > -				dev_err(client->dev,
> > -					"failed to attach to domain: %d\n",
> > -					err);
> > -				iommu_group_put(gr2d->group);
> > -				goto free;
> > -			}
> > -		}
> > +	gr2d->group = host1x_client_iommu_attach(client, false);
> > +	if (IS_ERR(gr2d->group)) {
> > +		err = PTR_ERR(gr2d->group);
> > +		dev_err(client->dev, "failed to attach to domain: %d\n", err);
> > +		goto free;
> >  	}
> >  
> > -	err = tegra_drm_register_client(tegra, drm);
> > +	err = tegra_drm_register_client(dev->dev_private, drm);
> >  	if (err < 0) {
> >  		dev_err(client->dev, "failed to register client: %d\n", err);
> >  		goto detach;
> > @@ -71,10 +62,7 @@ static int gr2d_init(struct host1x_client *client)
> >  	return 0;
> >  
> >  detach:
> > -	if (gr2d->group) {
> > -		iommu_detach_group(tegra->domain, gr2d->group);
> > -		iommu_group_put(gr2d->group);
> > -	}
> > +	host1x_client_iommu_detach(client, gr2d->group);
> >  free:
> >  	host1x_syncpt_free(client->syncpts[0]);
> >  put:
> > @@ -94,14 +82,10 @@ static int gr2d_exit(struct host1x_client *client)
> >  	if (err < 0)
> >  		return err;
> >  
> > +	host1x_client_iommu_detach(client, gr2d->group);
> >  	host1x_syncpt_free(client->syncpts[0]);
> >  	host1x_channel_put(gr2d->channel);
> >  
> > -	if (gr2d->group) {
> > -		iommu_detach_group(tegra->domain, gr2d->group);
> > -		iommu_group_put(gr2d->group);
> > -	}
> > -
> >  	return 0;
> >  }
> >  
> > diff --git a/drivers/gpu/drm/tegra/gr3d.c b/drivers/gpu/drm/tegra/gr3d.c
> > index e129f1afff33..98e3c67d0fb5 100644
> > --- a/drivers/gpu/drm/tegra/gr3d.c
> > +++ b/drivers/gpu/drm/tegra/gr3d.c
> > @@ -42,7 +42,6 @@ static int gr3d_init(struct host1x_client *client)
> >  	struct tegra_drm_client *drm = host1x_to_drm_client(client);
> >  	struct drm_device *dev = dev_get_drvdata(client->parent);
> >  	unsigned long flags = HOST1X_SYNCPT_HAS_BASE;
> > -	struct tegra_drm *tegra = dev->dev_private;
> >  	struct gr3d *gr3d = to_gr3d(drm);
> >  	int err;
> >  
> > @@ -56,19 +55,11 @@ static int gr3d_init(struct host1x_client *client)
> >  		goto put;
> >  	}
> >  
> > -	if (tegra->domain) {
> > -		gr3d->group = iommu_group_get(client->dev);
> > -
> > -		if (gr3d->group) {
> > -			err = iommu_attach_group(tegra->domain, gr3d->group);
> > -			if (err < 0) {
> > -				dev_err(client->dev,
> > -					"failed to attach to domain: %d\n",
> > -					err);
> > -				iommu_group_put(gr3d->group);
> > -				goto free;
> > -			}
> > -		}
> > +	gr3d->group = host1x_client_iommu_attach(client, false);
> > +	if (IS_ERR(gr3d->group)) {
> > +		err = PTR_ERR(gr3d->group);
> > +		dev_err(client->dev, "failed to attach to domain: %d\n", err);
> > +		goto free;
> >  	}
> >  
> >  	err = tegra_drm_register_client(dev->dev_private, drm);
> > @@ -80,10 +71,7 @@ static int gr3d_init(struct host1x_client *client)
> >  	return 0;
> >  
> >  detach:
> > -	if (gr3d->group) {
> > -		iommu_detach_group(tegra->domain, gr3d->group);
> > -		iommu_group_put(gr3d->group);
> > -	}
> > +	host1x_client_iommu_detach(client, gr3d->group);
> >  free:
> >  	host1x_syncpt_free(client->syncpts[0]);
> >  put:
> > @@ -95,7 +83,6 @@ static int gr3d_exit(struct host1x_client *client)
> >  {
> >  	struct tegra_drm_client *drm = host1x_to_drm_client(client);
> >  	struct drm_device *dev = dev_get_drvdata(client->parent);
> > -	struct tegra_drm *tegra = dev->dev_private;
> >  	struct gr3d *gr3d = to_gr3d(drm);
> >  	int err;
> >  
> > @@ -103,14 +90,10 @@ static int gr3d_exit(struct host1x_client *client)
> >  	if (err < 0)
> >  		return err;
> >  
> > +	host1x_client_iommu_detach(client, gr3d->group);
> >  	host1x_syncpt_free(client->syncpts[0]);
> >  	host1x_channel_put(gr3d->channel);
> >  
> > -	if (gr3d->group) {
> > -		iommu_detach_group(tegra->domain, gr3d->group);
> > -		iommu_group_put(gr3d->group);
> > -	}
> > -
> >  	return 0;
> >  }
> >  
> > 
> 
> Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
> 
> Though I'd prefer to have tegra->group renamed, maybe to 'shared_dc_group'.

tegra->group doesn't bother me at all. I think just the fact that it's
in struct tegra_drm implies that it is shared. It's also declared
closely to all the other "shared" variables, so I think that makes it
pretty clear. If there were other IOMMU groups I'd agree that renaming
it would be good to clarify the purpose. But as it is, I think there's
no need for that.

Thanks for the review!

Thierry

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