On Thu, Oct 24, 2019 at 06:07:54PM +0200, Daniel Vetter wrote:
> On Thu, Oct 24, 2019 at 05:10:30PM +0200, Thierry Reding wrote:
> > From: Thierry Reding <tred...@nvidia.com>
> > 
> > The ->load() and ->unload() drivers are midlayers and should be avoided
> > in modern drivers. Fix this by moving the code into the driver ->probe()
> > and ->remove() implementations, respectively.
> > 
> > Signed-off-by: Thierry Reding <tred...@nvidia.com>
> > ---
> >  drivers/gpu/drm/tegra/drm.c | 386 +++++++++++++++++-------------------
> >  1 file changed, 186 insertions(+), 200 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
> > index 3012f13bab97..bd7a00272965 100644
> > --- a/drivers/gpu/drm/tegra/drm.c
> > +++ b/drivers/gpu/drm/tegra/drm.c
> > @@ -82,202 +82,6 @@ tegra_drm_mode_config_helpers = {
> >     .atomic_commit_tail = tegra_atomic_commit_tail,
> >  };
> >  
> > -static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
> > -{
> > -   struct host1x_device *device = to_host1x_device(drm->dev);
> > -   struct iommu_domain *domain;
> > -   struct tegra_drm *tegra;
> > -   int err;
> > -
> > -   tegra = kzalloc(sizeof(*tegra), GFP_KERNEL);
> > -   if (!tegra)
> > -           return -ENOMEM;
> > -
> > -   /*
> > -    * If the Tegra DRM clients are backed by an IOMMU, push buffers are
> > -    * likely to be allocated beyond the 32-bit boundary if sufficient
> > -    * system memory is available. This is problematic on earlier Tegra
> > -    * generations where host1x supports a maximum of 32 address bits in
> > -    * the GATHER opcode. In this case, unless host1x is behind an IOMMU
> > -    * as well it won't be able to process buffers allocated beyond the
> > -    * 32-bit boundary.
> > -    *
> > -    * The DMA API will use bounce buffers in this case, so that could
> > -    * perhaps still be made to work, even if less efficient, but there
> > -    * is another catch: in order to perform cache maintenance on pages
> > -    * allocated for discontiguous buffers we need to map and unmap the
> > -    * SG table representing these buffers. This is fine for something
> > -    * small like a push buffer, but it exhausts the bounce buffer pool
> > -    * (typically on the order of a few MiB) for framebuffers (many MiB
> > -    * for any modern resolution).
> > -    *
> > -    * Work around this by making sure that Tegra DRM clients only use
> > -    * an IOMMU if the parent host1x also uses an IOMMU.
> > -    *
> > -    * Note that there's still a small gap here that we don't cover: if
> > -    * the DMA API is backed by an IOMMU there's no way to control which
> > -    * device is attached to an IOMMU and which isn't, except via wiring
> > -    * up the device tree appropriately. This is considered an problem
> > -    * of integration, so care must be taken for the DT to be consistent.
> > -    */
> > -   domain = iommu_get_domain_for_dev(drm->dev->parent);
> > -
> > -   if (domain && iommu_present(&platform_bus_type)) {
> > -           tegra->domain = iommu_domain_alloc(&platform_bus_type);
> > -           if (!tegra->domain) {
> > -                   err = -ENOMEM;
> > -                   goto free;
> > -           }
> > -
> > -           err = iova_cache_get();
> > -           if (err < 0)
> > -                   goto domain;
> > -   }
> > -
> > -   mutex_init(&tegra->clients_lock);
> > -   INIT_LIST_HEAD(&tegra->clients);
> > -
> > -   drm->dev_private = tegra;
> > -   tegra->drm = drm;
> > -
> > -   drm_mode_config_init(drm);
> > -
> > -   drm->mode_config.min_width = 0;
> > -   drm->mode_config.min_height = 0;
> > -
> > -   drm->mode_config.max_width = 4096;
> > -   drm->mode_config.max_height = 4096;
> > -
> > -   drm->mode_config.allow_fb_modifiers = true;
> > -
> > -   drm->mode_config.normalize_zpos = true;
> > -
> > -   drm->mode_config.funcs = &tegra_drm_mode_config_funcs;
> > -   drm->mode_config.helper_private = &tegra_drm_mode_config_helpers;
> > -
> > -   err = tegra_drm_fb_prepare(drm);
> > -   if (err < 0)
> > -           goto config;
> > -
> > -   drm_kms_helper_poll_init(drm);
> > -
> > -   err = host1x_device_init(device);
> > -   if (err < 0)
> > -           goto fbdev;
> > -
> > -   if (tegra->group) {
> > -           u64 carveout_start, carveout_end, gem_start, gem_end;
> > -           u64 dma_mask = dma_get_mask(&device->dev);
> > -           dma_addr_t start, end;
> > -           unsigned long order;
> > -
> > -           start = tegra->domain->geometry.aperture_start & dma_mask;
> > -           end = tegra->domain->geometry.aperture_end & dma_mask;
> > -
> > -           gem_start = start;
> > -           gem_end = end - CARVEOUT_SZ;
> > -           carveout_start = gem_end + 1;
> > -           carveout_end = end;
> > -
> > -           order = __ffs(tegra->domain->pgsize_bitmap);
> > -           init_iova_domain(&tegra->carveout.domain, 1UL << order,
> > -                            carveout_start >> order);
> > -
> > -           tegra->carveout.shift = iova_shift(&tegra->carveout.domain);
> > -           tegra->carveout.limit = carveout_end >> tegra->carveout.shift;
> > -
> > -           drm_mm_init(&tegra->mm, gem_start, gem_end - gem_start + 1);
> > -           mutex_init(&tegra->mm_lock);
> > -
> > -           DRM_DEBUG_DRIVER("IOMMU apertures:\n");
> > -           DRM_DEBUG_DRIVER("  GEM: %#llx-%#llx\n", gem_start, gem_end);
> > -           DRM_DEBUG_DRIVER("  Carveout: %#llx-%#llx\n", carveout_start,
> > -                            carveout_end);
> > -   } else if (tegra->domain) {
> > -           iommu_domain_free(tegra->domain);
> > -           tegra->domain = NULL;
> > -           iova_cache_put();
> > -   }
> > -
> > -   if (tegra->hub) {
> > -           err = tegra_display_hub_prepare(tegra->hub);
> > -           if (err < 0)
> > -                   goto device;
> > -   }
> > -
> > -   /*
> > -    * We don't use the drm_irq_install() helpers provided by the DRM
> > -    * core, so we need to set this manually in order to allow the
> > -    * DRM_IOCTL_WAIT_VBLANK to operate correctly.
> > -    */
> > -   drm->irq_enabled = true;
> > -
> > -   /* syncpoints are used for full 32-bit hardware VBLANK counters */
> > -   drm->max_vblank_count = 0xffffffff;
> > -
> > -   err = drm_vblank_init(drm, drm->mode_config.num_crtc);
> > -   if (err < 0)
> > -           goto hub;
> > -
> > -   drm_mode_config_reset(drm);
> > -
> > -   err = tegra_drm_fb_init(drm);
> > -   if (err < 0)
> > -           goto hub;
> > -
> > -   return 0;
> > -
> > -hub:
> > -   if (tegra->hub)
> > -           tegra_display_hub_cleanup(tegra->hub);
> > -device:
> > -   if (tegra->domain) {
> > -           mutex_destroy(&tegra->mm_lock);
> > -           drm_mm_takedown(&tegra->mm);
> > -           put_iova_domain(&tegra->carveout.domain);
> > -           iova_cache_put();
> > -   }
> > -
> > -   host1x_device_exit(device);
> > -fbdev:
> > -   drm_kms_helper_poll_fini(drm);
> > -   tegra_drm_fb_free(drm);
> > -config:
> > -   drm_mode_config_cleanup(drm);
> > -domain:
> > -   if (tegra->domain)
> > -           iommu_domain_free(tegra->domain);
> > -free:
> > -   kfree(tegra);
> > -   return err;
> > -}
> > -
> > -static void tegra_drm_unload(struct drm_device *drm)
> > -{
> > -   struct host1x_device *device = to_host1x_device(drm->dev);
> > -   struct tegra_drm *tegra = drm->dev_private;
> > -   int err;
> > -
> > -   drm_kms_helper_poll_fini(drm);
> > -   tegra_drm_fb_exit(drm);
> > -   drm_atomic_helper_shutdown(drm);
> > -   drm_mode_config_cleanup(drm);
> > -
> > -   err = host1x_device_exit(device);
> > -   if (err < 0)
> > -           return;
> > -
> > -   if (tegra->domain) {
> > -           mutex_destroy(&tegra->mm_lock);
> > -           drm_mm_takedown(&tegra->mm);
> > -           put_iova_domain(&tegra->carveout.domain);
> > -           iova_cache_put();
> > -           iommu_domain_free(tegra->domain);
> > -   }
> > -
> > -   kfree(tegra);
> > -}
> > -
> >  static int tegra_drm_open(struct drm_device *drm, struct drm_file *filp)
> >  {
> >     struct tegra_drm_file *fpriv;
> > @@ -1046,8 +850,6 @@ static int tegra_debugfs_init(struct drm_minor *minor)
> >  static struct drm_driver tegra_drm_driver = {
> >     .driver_features = DRIVER_MODESET | DRIVER_GEM |
> >                        DRIVER_ATOMIC | DRIVER_RENDER,
> > -   .load = tegra_drm_load,
> > -   .unload = tegra_drm_unload,
> >     .open = tegra_drm_open,
> >     .postclose = tegra_drm_postclose,
> >     .lastclose = drm_fb_helper_lastclose,
> > @@ -1231,6 +1033,8 @@ void tegra_drm_free(struct tegra_drm *tegra, size_t 
> > size, void *virt,
> >  static int host1x_drm_probe(struct host1x_device *dev)
> >  {
> >     struct drm_driver *driver = &tegra_drm_driver;
> > +   struct iommu_domain *domain;
> > +   struct tegra_drm *tegra;
> >     struct drm_device *drm;
> >     int err;
> >  
> > @@ -1238,18 +1042,179 @@ static int host1x_drm_probe(struct host1x_device 
> > *dev)
> >     if (IS_ERR(drm))
> >             return PTR_ERR(drm);
> >  
> > +   tegra = kzalloc(sizeof(*tegra), GFP_KERNEL);
> > +   if (!tegra) {
> > +           err = -ENOMEM;
> > +           goto put;
> > +   }
> > +
> > +   /*
> > +    * If the Tegra DRM clients are backed by an IOMMU, push buffers are
> > +    * likely to be allocated beyond the 32-bit boundary if sufficient
> > +    * system memory is available. This is problematic on earlier Tegra
> > +    * generations where host1x supports a maximum of 32 address bits in
> > +    * the GATHER opcode. In this case, unless host1x is behind an IOMMU
> > +    * as well it won't be able to process buffers allocated beyond the
> > +    * 32-bit boundary.
> > +    *
> > +    * The DMA API will use bounce buffers in this case, so that could
> > +    * perhaps still be made to work, even if less efficient, but there
> > +    * is another catch: in order to perform cache maintenance on pages
> > +    * allocated for discontiguous buffers we need to map and unmap the
> > +    * SG table representing these buffers. This is fine for something
> > +    * small like a push buffer, but it exhausts the bounce buffer pool
> > +    * (typically on the order of a few MiB) for framebuffers (many MiB
> > +    * for any modern resolution).
> > +    *
> > +    * Work around this by making sure that Tegra DRM clients only use
> > +    * an IOMMU if the parent host1x also uses an IOMMU.
> > +    *
> > +    * Note that there's still a small gap here that we don't cover: if
> > +    * the DMA API is backed by an IOMMU there's no way to control which
> > +    * device is attached to an IOMMU and which isn't, except via wiring
> > +    * up the device tree appropriately. This is considered an problem
> > +    * of integration, so care must be taken for the DT to be consistent.
> > +    */
> > +   domain = iommu_get_domain_for_dev(drm->dev->parent);
> > +
> > +   if (domain && iommu_present(&platform_bus_type)) {
> > +           tegra->domain = iommu_domain_alloc(&platform_bus_type);
> > +           if (!tegra->domain) {
> > +                   err = -ENOMEM;
> > +                   goto free;
> > +           }
> > +
> > +           err = iova_cache_get();
> > +           if (err < 0)
> > +                   goto domain;
> > +   }
> > +
> > +   mutex_init(&tegra->clients_lock);
> > +   INIT_LIST_HEAD(&tegra->clients);
> > +
> >     dev_set_drvdata(&dev->dev, drm);
> > +   drm->dev_private = tegra;
> > +   tegra->drm = drm;
> > +
> > +   drm_mode_config_init(drm);
> > +
> > +   drm->mode_config.min_width = 0;
> > +   drm->mode_config.min_height = 0;
> > +
> > +   drm->mode_config.max_width = 4096;
> > +   drm->mode_config.max_height = 4096;
> > +
> > +   drm->mode_config.allow_fb_modifiers = true;
> > +
> > +   drm->mode_config.normalize_zpos = true;
> > +
> > +   drm->mode_config.funcs = &tegra_drm_mode_config_funcs;
> > +   drm->mode_config.helper_private = &tegra_drm_mode_config_helpers;
> > +
> > +   err = tegra_drm_fb_prepare(drm);
> > +   if (err < 0)
> > +           goto config;
> > +
> > +   drm_kms_helper_poll_init(drm);
> > +
> > +   err = host1x_device_init(dev);
> > +   if (err < 0)
> > +           goto fbdev;
> > +
> > +   if (tegra->group) {
> > +           u64 carveout_start, carveout_end, gem_start, gem_end;
> > +           u64 dma_mask = dma_get_mask(&dev->dev);
> > +           dma_addr_t start, end;
> > +           unsigned long order;
> > +
> > +           start = tegra->domain->geometry.aperture_start & dma_mask;
> > +           end = tegra->domain->geometry.aperture_end & dma_mask;
> > +
> > +           gem_start = start;
> > +           gem_end = end - CARVEOUT_SZ;
> > +           carveout_start = gem_end + 1;
> > +           carveout_end = end;
> > +
> > +           order = __ffs(tegra->domain->pgsize_bitmap);
> > +           init_iova_domain(&tegra->carveout.domain, 1UL << order,
> > +                            carveout_start >> order);
> > +
> > +           tegra->carveout.shift = iova_shift(&tegra->carveout.domain);
> > +           tegra->carveout.limit = carveout_end >> tegra->carveout.shift;
> > +
> > +           drm_mm_init(&tegra->mm, gem_start, gem_end - gem_start + 1);
> > +           mutex_init(&tegra->mm_lock);
> > +
> > +           DRM_DEBUG_DRIVER("IOMMU apertures:\n");
> > +           DRM_DEBUG_DRIVER("  GEM: %#llx-%#llx\n", gem_start, gem_end);
> > +           DRM_DEBUG_DRIVER("  Carveout: %#llx-%#llx\n", carveout_start,
> > +                            carveout_end);
> > +   } else if (tegra->domain) {
> > +           iommu_domain_free(tegra->domain);
> > +           tegra->domain = NULL;
> > +           iova_cache_put();
> > +   }
> > +
> > +   if (tegra->hub) {
> > +           err = tegra_display_hub_prepare(tegra->hub);
> > +           if (err < 0)
> > +                   goto device;
> > +   }
> > +
> > +   /*
> > +    * We don't use the drm_irq_install() helpers provided by the DRM
> > +    * core, so we need to set this manually in order to allow the
> > +    * DRM_IOCTL_WAIT_VBLANK to operate correctly.
> > +    */
> > +   drm->irq_enabled = true;
> > +
> > +   /* syncpoints are used for full 32-bit hardware VBLANK counters */
> > +   drm->max_vblank_count = 0xffffffff;
> > +
> > +   err = drm_vblank_init(drm, drm->mode_config.num_crtc);
> > +   if (err < 0)
> > +           goto hub;
> > +
> > +   drm_mode_config_reset(drm);
> > +
> > +   err = tegra_drm_fb_init(drm);
> > +   if (err < 0)
> > +           goto hub;
> >  
> >     err = drm_fb_helper_remove_conflicting_framebuffers(NULL, "tegradrmfb", 
> > false);
> 
> I think you want to do this before you set up the drmfb. Well probably you
> want to do this as the one of the very first things in your probe code,
> before you start touching any of the hw. At least that's what the old
> order did.

Hm... you're right. I had actually wondered about this and then
concluded that it might be best to only remove the conflicting
framebuffers when it was relatively certain that the driver could
correctly create a new DRM framebuffer.

But yeah, it definitely needs to kick out the conflicting framebuffer
before the call to tegra_drm_fb_init().

I'll Cc MichaƂ on the next version, maybe he's got a way to actually
test this. I don't have access to any hardware where the firmware
installs a framebuffer.

Thierry

> 
> >     if (err < 0)
> > -           goto put;
> > +           goto fb;
> >  
> >     err = drm_dev_register(drm, 0);
> >     if (err < 0)
> > -           goto put;
> > +           goto fb;
> >  
> >     return 0;
> >  
> > +fb:
> > +   tegra_drm_fb_exit(drm);
> > +hub:
> > +   if (tegra->hub)
> > +           tegra_display_hub_cleanup(tegra->hub);
> > +device:
> > +   if (tegra->domain) {
> > +           mutex_destroy(&tegra->mm_lock);
> > +           drm_mm_takedown(&tegra->mm);
> > +           put_iova_domain(&tegra->carveout.domain);
> > +           iova_cache_put();
> > +   }
> > +
> > +   host1x_device_exit(dev);
> > +fbdev:
> > +   drm_kms_helper_poll_fini(drm);
> > +   tegra_drm_fb_free(drm);
> > +config:
> > +   drm_mode_config_cleanup(drm);
> > +domain:
> > +   if (tegra->domain)
> > +           iommu_domain_free(tegra->domain);
> > +free:
> > +   kfree(tegra);
> >  put:
> >     drm_dev_put(drm);
> >     return err;
> > @@ -1258,8 +1223,29 @@ static int host1x_drm_probe(struct host1x_device 
> > *dev)
> >  static int host1x_drm_remove(struct host1x_device *dev)
> >  {
> >     struct drm_device *drm = dev_get_drvdata(&dev->dev);
> > +   struct tegra_drm *tegra = drm->dev_private;
> > +   int err;
> >  
> >     drm_dev_unregister(drm);
> > +
> > +   drm_kms_helper_poll_fini(drm);
> > +   tegra_drm_fb_exit(drm);
> > +   drm_atomic_helper_shutdown(drm);
> > +   drm_mode_config_cleanup(drm);
> > +
> > +   err = host1x_device_exit(dev);
> > +   if (err < 0)
> > +           dev_err(&dev->dev, "host1x device cleanup failed: %d\n", err);
> > +
> > +   if (tegra->domain) {
> > +           mutex_destroy(&tegra->mm_lock);
> > +           drm_mm_takedown(&tegra->mm);
> > +           put_iova_domain(&tegra->carveout.domain);
> > +           iova_cache_put();
> > +           iommu_domain_free(tegra->domain);
> > +   }
> > +
> > +   kfree(tegra);
> >     drm_dev_put(drm);
> >  
> >     return 0;
> 
> Aside from the one question:
> 
> Reviewed-by: Daniel Vetter <daniel.vet...@ffwll.ch>
> 
> > -- 
> > 2.23.0
> > 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch

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