Re: [PATCH 09/10] drm/gma500: Rewrite GTT page insert/remove without struct gtt_range

On Tue, Sep 28, 2021 at 10:44 AM Thomas Zimmermann tzimmermann@suse.de wrote:

struct gtt_range represents a GEM object and should not be used for GTT setup. Change psb_gtt_insert() and psb_gtt_remove() to receive all necessary parameters from their caller. This also eliminates possible failure from psb_gtt_insert().

There's one exception in psb_gtt_restore(), which requires an upcast from struct resource to struct gtt_range when restoring the GTT after hibernation. A possible solution would track the GEM objects that need restoration separately from the GTT resource.

We could also treat the GTT as registers and save/restore it that way. OFC that approach would waste a bit of memory.

Rename the functions to psb_gtt_insert_pages() and psb_gtt_remove_pages() to reflect their similarity to MMU interfaces.

Signed-off-by: Thomas Zimmermann tzimmermann@suse.de

drivers/gpu/drm/gma500/gem.c | 13 ++---- drivers/gpu/drm/gma500/gtt.c | 87 ++++++++++++------------------------ drivers/gpu/drm/gma500/gtt.h | 5 ++- 3 files changed, 35 insertions(+), 70 deletions(-)

diff --git a/drivers/gpu/drm/gma500/gem.c b/drivers/gpu/drm/gma500/gem.c index a88d51a3aa2a..fd556ba2c044 100644 --- a/drivers/gpu/drm/gma500/gem.c +++ b/drivers/gpu/drm/gma500/gem.c @@ -23,7 +23,6 @@

int psb_gem_pin(struct gtt_range *gt) {

•   int ret = 0;
    struct drm_device *dev = gt->gem.dev;
    struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
    u32 gpu_base = dev_priv->gtt.gatt_start;
  

@@ -43,10 +42,7 @@ int psb_gem_pin(struct gtt_range *gt)

    set_pages_array_wc(pages, npages);

•   ret = psb_gtt_insert(dev, gt);
  

•   if (ret)
  

•           goto err_drm_gem_put_pages;
  

•   psb_gtt_insert_pages(dev_priv, &gt->resource, pages);
    psb_mmu_insert_pages(psb_mmu_get_default_pd(dev_priv->mmu), pages,
                         (gpu_base + gt->offset), npages, 0, 0,
                         PSB_MMU_CACHED_MEMORY);
  

@@ -59,10 +55,6 @@ int psb_gem_pin(struct gtt_range *gt) mutex_unlock(&dev_priv->gtt_mutex);

    return 0;

-err_drm_gem_put_pages:

•   drm_gem_put_pages(&gt->gem, pages, true, false);
  

•   return ret;
  

}

void psb_gem_unpin(struct gtt_range *gt) @@ -82,13 +74,14 @@ void psb_gem_unpin(struct gtt_range *gt)

    psb_mmu_remove_pages(psb_mmu_get_default_pd(dev_priv->mmu),
                                 (gpu_base + gt->offset), gt->npage, 0, 0);

•   psb_gtt_remove(dev, gt);
  

•   psb_gtt_remove_pages(dev_priv, &gt->resource);
  
    /* Reset caching flags */
    set_pages_array_wb(gt->pages, gt->npage);
  
    drm_gem_put_pages(&gt->gem, gt->pages, true, false);
    gt->pages = NULL;
  

•   gt->npage = 0;
  
  

out: mutex_unlock(&dev_priv->gtt_mutex); diff --git a/drivers/gpu/drm/gma500/gtt.c b/drivers/gpu/drm/gma500/gtt.c index 244de618e612..cf71a2396c16 100644 --- a/drivers/gpu/drm/gma500/gtt.c +++ b/drivers/gpu/drm/gma500/gtt.c @@ -66,85 +66,51 @@ static inline uint32_t psb_gtt_mask_pte(uint32_t pfn, int type) return (pfn << PAGE_SHIFT) | mask; }

-/**

• • psb_gtt_entry           -       find the GTT entries for a gtt_range
    

• • @dev: our DRM device
    

• • @r: our GTT range
    

• • Given a gtt_range object return the GTT offset of the page table
    

• • entries for this gtt_range
    

• */

-static u32 __iomem *psb_gtt_entry(struct drm_device *dev, struct gtt_range *r) +static u32 __iomem *psb_gtt_entry(struct drm_psb_private *pdev, const struct resource *res) {

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   unsigned long offset;
  

•   offset = r->resource.start - dev_priv->gtt_mem->start;
  

•   unsigned long offset = res->start - pdev->gtt_mem->start;
  
  

•   return dev_priv->gtt_map + (offset >> PAGE_SHIFT);
  

•   return pdev->gtt_map + (offset >> PAGE_SHIFT);
  

}

-/**

• • psb_gtt_insert  -       put an object into the GTT
    

• • @dev: our DRM device
    

• • @r: our GTT range
    

• • Take our preallocated GTT range and insert the GEM object into
    

• • the GTT. This is protected via the gtt mutex which the caller
    

• • must hold.
    

• */

-int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r) +void psb_gtt_insert_pages(struct drm_psb_private *pdev, const struct resource *res,

•                     struct page **pages)
  

{

•   resource_size_t npages, i;
    u32 __iomem *gtt_slot;
    u32 pte;
  

•   int i;
  
  

•   if (r->pages == NULL) {
  

•           WARN_ON(1);
  

•           return -EINVAL;
  

•   }
  

•   WARN_ON(r->stolen);     /* refcount these maybe ? */
  

•   /* Write our page entries into the GTT itself */
  
  

•   gtt_slot = psb_gtt_entry(dev, r);
  

•   npages = resource_size(res) >> PAGE_SHIFT;
  

•   gtt_slot = psb_gtt_entry(pdev, res);
  
  

•   /* Write our page entries into the GTT itself */
  

•   for (i = 0; i < r->npage; i++) {
  

•           pte = psb_gtt_mask_pte(page_to_pfn(r->pages[i]),
  

•                                  PSB_MMU_CACHED_MEMORY);
  

•           iowrite32(pte, gtt_slot++);
  

•   for (i = 0; i < npages; ++i, ++gtt_slot) {
  

•           pte = psb_gtt_mask_pte(page_to_pfn(pages[i]), PSB_MMU_CACHED_MEMORY);
  

•           iowrite32(pte, gtt_slot);
    }
  
    /* Make sure all the entries are set before we return */
    ioread32(gtt_slot - 1);
  

•   return 0;
  

}

-/**

• • psb_gtt_remove  -       remove an object from the GTT
    

• • @dev: our DRM device
    

• • @r: our GTT range
    

• • Remove a preallocated GTT range from the GTT. Overwrite all the
    

• • page table entries with the dummy page. This is protected via the gtt
    

• • mutex which the caller must hold.
    

• */

-void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r) +void psb_gtt_remove_pages(struct drm_psb_private *pdev, const struct resource *res) {

•   struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
  

•   resource_size_t npages, i;
    u32 __iomem *gtt_slot;
    u32 pte;
  

•   int i;
  
  

•   WARN_ON(r->stolen);
  

•   /* Install scratch page for the resource */
  

•   pte = psb_gtt_mask_pte(page_to_pfn(pdev->scratch_page), PSB_MMU_CACHED_MEMORY);
  
  

•   gtt_slot = psb_gtt_entry(dev, r);
  

•   pte = psb_gtt_mask_pte(page_to_pfn(dev_priv->scratch_page),
  

•                          PSB_MMU_CACHED_MEMORY);
  

•   npages = resource_size(res) >> PAGE_SHIFT;
  

•   gtt_slot = psb_gtt_entry(pdev, res);
  
  

•   for (i = 0; i < r->npage; i++)
  

•           iowrite32(pte, gtt_slot++);
  

•   for (i = 0; i < npages; ++i, ++gtt_slot)
  

•           iowrite32(pte, gtt_slot);
  

•   /* Make sure all the entries are set before we return */
    ioread32(gtt_slot - 1);
  

}

@@ -334,9 +300,14 @@ int psb_gtt_restore(struct drm_device *dev) psb_gtt_init(dev, 1);

    while (r != NULL) {

•           /*
  

•            * TODO: GTT restoration needs a refactoring, so that we don't have to touch
  

•            *       struct gtt_range here. The type represents a GEM object and is not
  

•            *       related to the GTT itself.
  

•            */
            range = container_of(r, struct gtt_range, resource);
            if (range->pages) {
  

•                   psb_gtt_insert(dev, range);
  

•                   psb_gtt_insert_pages(dev_priv, &range->resource, range->pages);
                    size += range->resource.end - range->resource.start;
                    restored++;
            }
  

diff --git a/drivers/gpu/drm/gma500/gtt.h b/drivers/gpu/drm/gma500/gtt.h index 7af71617e0c5..6a28e24a18b7 100644 --- a/drivers/gpu/drm/gma500/gtt.h +++ b/drivers/gpu/drm/gma500/gtt.h @@ -49,7 +49,8 @@ int psb_gtt_allocate_resource(struct drm_psb_private *pdev, struct resource *res const char *name, resource_size_t size, resource_size_t align, bool stolen, u32 offset[static 1]);

-int psb_gtt_insert(struct drm_device *dev, struct gtt_range *r); -void psb_gtt_remove(struct drm_device *dev, struct gtt_range *r); +void psb_gtt_insert_pages(struct drm_psb_private *pdev, const struct resource *res,

•                     struct page **pages);
  

+void psb_gtt_remove_pages(struct drm_psb_private *pdev, const struct resource *res);

#endif

2.33.0