drm/gma500: Move GTT locking into GTT helpers

Acquire the GTT mutex in psb_gtt_{insert,remove}_pages(). Remove
locking from callers. Also remove the GTT locking around the resume
code. Resume does not run concurrently with other GTT operations.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220308195222.13471-4-tzimmermann@suse.de

drivers/gpu/drm/gma500/gem.c

@@ -35,15 +35,13 @@ int psb_gem_pin(struct psb_gem_object *pobj)
 	if (drm_WARN_ONCE(dev, ret, "dma_resv_lock() failed, ret=%d\n", ret))
 		return ret;
 
-	mutex_lock(&dev_priv->gtt_mutex);
-
 	if (pobj->in_gart || pobj->stolen)
 		goto out; /* already mapped */
 
 	pages = drm_gem_get_pages(obj);
 	if (IS_ERR(pages)) {
 		ret = PTR_ERR(pages);
-		goto err_mutex_unlock;
+		goto err_dma_resv_unlock;
 	}
 
 	npages = obj->size / PAGE_SIZE;
@@ -59,13 +57,11 @@ int psb_gem_pin(struct psb_gem_object *pobj)
 
 out:
 	++pobj->in_gart;
-	mutex_unlock(&dev_priv->gtt_mutex);
 	dma_resv_unlock(obj->resv);
 
 	return 0;
 
-err_mutex_unlock:
-	mutex_unlock(&dev_priv->gtt_mutex);
+err_dma_resv_unlock:
 	dma_resv_unlock(obj->resv);
 	return ret;
 }
@@ -83,8 +79,6 @@ void psb_gem_unpin(struct psb_gem_object *pobj)
 	if (drm_WARN_ONCE(dev, ret, "dma_resv_lock() failed, ret=%d\n", ret))
 		return;
 
-	mutex_lock(&dev_priv->gtt_mutex);
-
 	WARN_ON(!pobj->in_gart);
 
 	--pobj->in_gart;
@@ -105,7 +99,6 @@ void psb_gem_unpin(struct psb_gem_object *pobj)
 	pobj->pages = NULL;
 
 out:
-	mutex_unlock(&dev_priv->gtt_mutex);
 	dma_resv_unlock(obj->resv);
 }
 

drivers/gpu/drm/gma500/gtt.c

@@ -74,11 +74,7 @@ static u32 __iomem *psb_gtt_entry(struct drm_psb_private *pdev, const struct res
 	return pdev->gtt_map + (offset >> PAGE_SHIFT);
 }
 
-/*
- * 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.
- */
+/* Acquires GTT mutex internally. */
 void psb_gtt_insert_pages(struct drm_psb_private *pdev, const struct resource *res,
 			  struct page **pages)
 {
@@ -86,6 +82,8 @@ void psb_gtt_insert_pages(struct drm_psb_private *pdev, const struct resource *r
 	u32 __iomem *gtt_slot;
 	u32 pte;
 
+	mutex_lock(&pdev->gtt_mutex);
+
 	/* Write our page entries into the GTT itself */
 
 	npages = resource_size(res) >> PAGE_SHIFT;
@@ -98,19 +96,19 @@ void psb_gtt_insert_pages(struct drm_psb_private *pdev, const struct resource *r
 
 	/* Make sure all the entries are set before we return */
 	ioread32(gtt_slot - 1);
+
+	mutex_unlock(&pdev->gtt_mutex);
 }
 
-/*
- * 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.
- */
+/* Acquires GTT mutex internally. */
 void psb_gtt_remove_pages(struct drm_psb_private *pdev, const struct resource *res)
 {
 	resource_size_t npages, i;
 	u32 __iomem *gtt_slot;
 	u32 pte;
 
+	mutex_lock(&pdev->gtt_mutex);
+
 	/* Install scratch page for the resource */
 
 	pte = psb_gtt_mask_pte(page_to_pfn(pdev->scratch_page), PSB_MMU_CACHED_MEMORY);
@@ -123,6 +121,8 @@ void psb_gtt_remove_pages(struct drm_psb_private *pdev, const struct resource *r
 
 	/* Make sure all the entries are set before we return */
 	ioread32(gtt_slot - 1);
+
+	mutex_unlock(&pdev->gtt_mutex);
 }
 
 static void psb_gtt_alloc(struct drm_device *dev)
@@ -306,8 +306,6 @@ int psb_gtt_restore(struct drm_device *dev)
 	struct psb_gem_object *pobj;
 	unsigned int restored = 0, total = 0, size = 0;
 
-	/* On resume, the gtt_mutex is already initialized */
-	mutex_lock(&dev_priv->gtt_mutex);
 	psb_gtt_init(dev, 1);
 
 	while (r != NULL) {
@@ -325,7 +323,7 @@ int psb_gtt_restore(struct drm_device *dev)
 		r = r->sibling;
 		total++;
 	}
-	mutex_unlock(&dev_priv->gtt_mutex);
+
 	DRM_DEBUG_DRIVER("Restored %u of %u gtt ranges (%u KB)", restored,
 			 total, (size / 1024));