drm/v3d: Enable V3D to use different PAGE_SIZE

Currently, the V3D driver uses PAGE_SHIFT over the assumption that
PAGE_SHIFT = 12, as the PAGE_SIZE = 4KB. But, the RPi 5 is using
PAGE_SIZE = 16KB, so the MMU PAGE_SHIFT is different than the system's
PAGE_SHIFT.

Enable V3D to be used in system's with any PAGE_SIZE by making sure that
everything MMU-related uses the MMU page shift.
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240214193503.164462-1-mcanal@igalia.com

drivers/gpu/drm/v3d/v3d_bo.c

@@ -40,7 +40,7 @@ void v3d_free_object(struct drm_gem_object *obj)
 
 	mutex_lock(&v3d->bo_lock);
 	v3d->bo_stats.num_allocated--;
-	v3d->bo_stats.pages_allocated -= obj->size >> PAGE_SHIFT;
+	v3d->bo_stats.pages_allocated -= obj->size >> V3D_MMU_PAGE_SHIFT;
 	mutex_unlock(&v3d->bo_lock);
 
 	spin_lock(&v3d->mm_lock);
@@ -109,8 +109,8 @@ v3d_bo_create_finish(struct drm_gem_object *obj)
 	 * lifetime of the BO.
 	 */
 	ret = drm_mm_insert_node_generic(&v3d->mm, &bo->node,
-					 obj->size >> PAGE_SHIFT,
-					 GMP_GRANULARITY >> PAGE_SHIFT, 0, 0);
+					 obj->size >> V3D_MMU_PAGE_SHIFT,
+					 GMP_GRANULARITY >> V3D_MMU_PAGE_SHIFT, 0, 0);
 	spin_unlock(&v3d->mm_lock);
 	if (ret)
 		return ret;
@@ -118,7 +118,7 @@ v3d_bo_create_finish(struct drm_gem_object *obj)
 	/* Track stats for /debug/dri/n/bo_stats. */
 	mutex_lock(&v3d->bo_lock);
 	v3d->bo_stats.num_allocated++;
-	v3d->bo_stats.pages_allocated += obj->size >> PAGE_SHIFT;
+	v3d->bo_stats.pages_allocated += obj->size >> V3D_MMU_PAGE_SHIFT;
 	mutex_unlock(&v3d->bo_lock);
 
 	v3d_mmu_insert_ptes(bo);
@@ -201,7 +201,7 @@ int v3d_create_bo_ioctl(struct drm_device *dev, void *data,
 	if (IS_ERR(bo))
 		return PTR_ERR(bo);
 
-	args->offset = bo->node.start << PAGE_SHIFT;
+	args->offset = bo->node.start << V3D_MMU_PAGE_SHIFT;
 
 	ret = drm_gem_handle_create(file_priv, &bo->base.base, &args->handle);
 	drm_gem_object_put(&bo->base.base);
@@ -246,7 +246,7 @@ int v3d_get_bo_offset_ioctl(struct drm_device *dev, void *data,
 	}
 	bo = to_v3d_bo(gem_obj);
 
-	args->offset = bo->node.start << PAGE_SHIFT;
+	args->offset = bo->node.start << V3D_MMU_PAGE_SHIFT;
 
 	drm_gem_object_put(gem_obj);
 	return 0;

drivers/gpu/drm/v3d/v3d_debugfs.c

@@ -219,7 +219,7 @@ static int v3d_debugfs_bo_stats(struct seq_file *m, void *unused)
 	seq_printf(m, "allocated bos:          %d\n",
 		   v3d->bo_stats.num_allocated);
 	seq_printf(m, "allocated bo size (kb): %ld\n",
-		   (long)v3d->bo_stats.pages_allocated << (PAGE_SHIFT - 10));
+		   (long)v3d->bo_stats.pages_allocated << (V3D_MMU_PAGE_SHIFT - 10));
 	mutex_unlock(&v3d->bo_lock);
 
 	return 0;

drivers/gpu/drm/v3d/v3d_drv.h

@@ -19,6 +19,8 @@ struct reset_control;
 
 #define GMP_GRANULARITY (128 * 1024)
 
+#define V3D_MMU_PAGE_SHIFT 12
+
 #define V3D_MAX_QUEUES (V3D_CPU + 1)
 
 static inline char *v3d_queue_to_string(enum v3d_queue queue)

drivers/gpu/drm/v3d/v3d_irq.c

@@ -70,7 +70,7 @@ v3d_overflow_mem_work(struct work_struct *work)
 	list_add_tail(&bo->unref_head, &v3d->bin_job->render->unref_list);
 	spin_unlock_irqrestore(&v3d->job_lock, irqflags);
 
-	V3D_CORE_WRITE(0, V3D_PTB_BPOA, bo->node.start << PAGE_SHIFT);
+	V3D_CORE_WRITE(0, V3D_PTB_BPOA, bo->node.start << V3D_MMU_PAGE_SHIFT);
 	V3D_CORE_WRITE(0, V3D_PTB_BPOS, obj->size);
 
 out:

drivers/gpu/drm/v3d/v3d_mmu.c

@@ -21,8 +21,6 @@
 #include "v3d_drv.h"
 #include "v3d_regs.h"
 
-#define V3D_MMU_PAGE_SHIFT 12
-
 /* Note: All PTEs for the 1MB superpage must be filled with the
  * superpage bit set.
  */