path: root/drivers/gpu/drm/vc4/vc4_bo.c

/*
 * Copyright © 2014-2015 Broadcom
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/*
 * VC4 GEM BO management support.
 *
 * The VC4 GPU architecture (both scanout and rendering) has direct
 * access to system memory with no MMU in between.  To support it, we
 * use the GEM CMA helper functions to allocate contiguous ranges of
 * physical memory for our BOs.
 */

#include "vc4_drv.h"
#include "uapi/drm/vc4_drm.h"

static struct {
	u32 num_allocated;
	u32 size_allocated;
	u32 num_cached;
	u32 size_cached;
} bo_stats;

static void
vc4_bo_stats_dump(void)
{
	DRM_INFO("num bos allocated: %d\n",
		 bo_stats.num_allocated);
	DRM_INFO("size bos allocated: %dkb\n",
		 bo_stats.size_allocated / 1024);
	DRM_INFO("num bos used: %d\n",
		 bo_stats.num_allocated - bo_stats.num_cached);
	DRM_INFO("size bos used: %dkb\n",
		 (bo_stats.size_allocated - bo_stats.size_cached) / 1024);
	DRM_INFO("num bos cached: %d\n",
		 bo_stats.num_cached);
	DRM_INFO("size bos cached: %dkb\n",
		 bo_stats.size_cached / 1024);
}

static uint32_t
bo_page_index(size_t size)
{
	return (size / PAGE_SIZE) - 1;
}

static void
vc4_bo_destroy(struct vc4_bo *bo)
{
	bo_stats.num_allocated--;
	bo_stats.size_allocated -= bo->base.base.size;
	drm_gem_cma_free_object(&bo->base.base);
}

static void
vc4_bo_remove_from_cache(struct vc4_bo *bo)
{
	bo_stats.num_cached--;
	bo_stats.size_cached -= bo->base.base.size;

	list_del(&bo->unref_head);
	list_del(&bo->size_head);
}

static struct list_head *
vc4_get_cache_list_for_size(struct drm_device *dev, size_t size)
{
	struct vc4_dev *vc4 = to_vc4_dev(dev);
	uint32_t page_index = bo_page_index(size);

	if (vc4->bo_cache.size_list_size <= page_index) {
		uint32_t new_size = max(vc4->bo_cache.size_list_size * 2,
					page_index + 1);
		struct list_head *new_list;
		uint32_t i;

		new_list = kmalloc(new_size * sizeof(struct list_head),
				   GFP_KERNEL);
		if (!new_list)
			return NULL;

		/* Rebase the old cached BO lists to their new list
		 * head locations.
		 */
		for (i = 0; i < vc4->bo_cache.size_list_size; i++) {
			struct list_head *old_list = &vc4->bo_cache.size_list[i];
			if (list_empty(old_list))
				INIT_LIST_HEAD(&new_list[i]);
			else
				list_replace(old_list, &new_list[i]);
		}
		/* And initialize the brand new BO list heads. */
		for (i = vc4->bo_cache.size_list_size; i < new_size; i++)
			INIT_LIST_HEAD(&new_list[i]);

		kfree(vc4->bo_cache.size_list);
		vc4->bo_cache.size_list = new_list;
		vc4->bo_cache.size_list_size = new_size;
	}

	return &vc4->bo_cache.size_list[page_index];
}

void
vc4_bo_cache_purge(struct drm_device *dev)
{
	struct vc4_dev *vc4 = to_vc4_dev(dev);

	while (!list_empty(&vc4->bo_cache.time_list)) {
		struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
						    struct vc4_bo, unref_head);
		vc4_bo_remove_from_cache(bo);
		vc4_bo_destroy(bo);
	}
}

struct vc4_bo *
vc4_bo_create(struct drm_device *dev, size_t unaligned_size)
{
	struct vc4_dev *vc4 = to_vc4_dev(dev);
	uint32_t size = roundup(unaligned_size, PAGE_SIZE);
	uint32_t page_index = bo_page_index(size);
	struct drm_gem_cma_object *cma_obj;
	int pass;

	if (size == 0)
		return NULL;

	/* First, try to get a vc4_bo from the kernel BO cache. */
	if (vc4->bo_cache.size_list_size > page_index) {
		if (!list_empty(&vc4->bo_cache.size_list[page_index])) {
			struct vc4_bo *bo =
				list_first_entry(&vc4->bo_cache.size_list[page_index],
						 struct vc4_bo, size_head);
			vc4_bo_remove_from_cache(bo);
			kref_init(&bo->base.base.refcount);
			return bo;
		}
	}

	/* Otherwise, make a new BO. */
	for (pass = 0; ; pass++) {
		cma_obj = drm_gem_cma_create(dev, size);
		if (!IS_ERR(cma_obj))
			break;

		switch (pass) {
		case 0:
			/*
			 * If we've run out of CMA memory, kill the cache of
			 * CMA allocations we've got laying around and try again.
			 */
			vc4_bo_cache_purge(dev);
			break;
		case 1:
			/*
			 * Getting desperate, so try to wait for any
			 * previous rendering to finish, free its
			 * unreferenced BOs to the cache, and then
			 * free the cache.
			 */
			vc4_wait_for_seqno(dev, vc4->emit_seqno, ~0ull);
			vc4_job_handle_completed(vc4);
			vc4_bo_cache_purge(dev);
			break;
		case 3:
			DRM_ERROR("Failed to allocate from CMA:\n");
			vc4_bo_stats_dump();
			return NULL;
		}
	}

	bo_stats.num_allocated++;
	bo_stats.size_allocated += size;

	return to_vc4_bo(&cma_obj->base);
}

int
vc4_dumb_create(struct drm_file *file_priv,
		struct drm_device *dev,
		struct drm_mode_create_dumb *args)
{
	int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
	struct vc4_bo *bo = NULL;
	int ret;

	if (args->pitch < min_pitch)
		args->pitch = min_pitch;

	if (args->size < args->pitch * args->height)
		args->size = args->pitch * args->height;

	mutex_lock(&dev->struct_mutex);
	bo = vc4_bo_create(dev, roundup(args->size, PAGE_SIZE));
	mutex_unlock(&dev->struct_mutex);
	if (!bo)
		return -ENOMEM;

	ret = drm_gem_handle_create(file_priv, &bo->base.base, &args->handle);
	drm_gem_object_unreference_unlocked(&bo->base.base);

	return ret;
}

static void
vc4_bo_cache_free_old(struct drm_device *dev)
{
	struct vc4_dev *vc4 = to_vc4_dev(dev);
	unsigned long expire_time = jiffies - msecs_to_jiffies(1000);

	while (!list_empty(&vc4->bo_cache.time_list)) {
		struct vc4_bo *bo = list_last_entry(&vc4->bo_cache.time_list,
						    struct vc4_bo, unref_head);
		if (time_before(expire_time, bo->free_time)) {
			mod_timer(&vc4->bo_cache.time_timer,
				  round_jiffies_up(jiffies +
						   msecs_to_jiffies(1000)));
			return;
		}

		vc4_bo_remove_from_cache(bo);
		vc4_bo_destroy(bo);
	}
}

/* Called on the last userspace/kernel unreference of the BO.  Returns
 * it to the BO cache if possible, otherwise frees it.
 *
 * Note that this is called with the struct_mutex held.
 */
void
vc4_free_object(struct drm_gem_object *gem_bo)
{
	struct drm_device *dev = gem_bo->dev;
	struct vc4_dev *vc4 = to_vc4_dev(dev);
	struct vc4_bo *bo = to_vc4_bo(gem_bo);
	struct list_head *cache_list;

	/* If the object references someone else's memory, we can't cache it.
	 */
	if (gem_bo->import_attach) {
		vc4_bo_destroy(bo);
		return;
	}

	/* Don't cache if it was publicly named. */
	if (gem_bo->name) {
		vc4_bo_destroy(bo);
		return;
	}

	cache_list = vc4_get_cache_list_for_size(dev, gem_bo->size);
	if (!cache_list) {
		vc4_bo_destroy(bo);
		return;
	}

	kfree(bo->validated_shader);
	bo->validated_shader = NULL;

	/* If the BO was exported, and it's made it to this point,
	 * then the dmabuf usage has been completely finished (so it's
	 * safe now to let it turn into a shader again).
	 */
	bo->dma_buf_import_export = false;

	bo->free_time = jiffies;
	list_add(&bo->size_head, cache_list);
	list_add(&bo->unref_head, &vc4->bo_cache.time_list);

	bo_stats.num_cached++;
	bo_stats.size_cached += gem_bo->size;

	vc4_bo_cache_free_old(dev);
}

static void
vc4_bo_cache_time_work(struct work_struct *work)
{
	struct vc4_dev *vc4 =
		container_of(work, struct vc4_dev, bo_cache.time_work);
	struct drm_device *dev = vc4->dev;

	mutex_lock(&dev->struct_mutex);
	vc4_bo_cache_free_old(dev);
	mutex_unlock(&dev->struct_mutex);
}

static void
vc4_bo_cache_time_timer(unsigned long data)
{
	struct drm_device *dev = (struct drm_device *)data;
	struct vc4_dev *vc4 = to_vc4_dev(dev);

	schedule_work(&vc4->bo_cache.time_work);
}

void
vc4_bo_cache_init(struct drm_device *dev)
{
	struct vc4_dev *vc4 = to_vc4_dev(dev);

	INIT_LIST_HEAD(&vc4->bo_cache.time_list);

	INIT_WORK(&vc4->bo_cache.time_work, vc4_bo_cache_time_work);
	setup_timer(&vc4->bo_cache.time_timer,
		    vc4_bo_cache_time_timer,
		    (unsigned long) dev);
}

void
vc4_bo_cache_destroy(struct drm_device *dev)
{
	struct vc4_dev *vc4 = to_vc4_dev(dev);

	del_timer(&vc4->bo_cache.time_timer);
	cancel_work_sync(&vc4->bo_cache.time_work);

	vc4_bo_cache_purge(dev);

	if (bo_stats.num_allocated) {
		DRM_ERROR("Destroying BO cache while BOs still allocated:\n");
		vc4_bo_stats_dump();
	}
}

struct drm_gem_object *
vc4_prime_import(struct drm_device *dev, struct dma_buf *dma_buf)
{
	struct drm_gem_object *obj = drm_gem_prime_import(dev, dma_buf);

	if (!IS_ERR_OR_NULL(obj)) {
		struct vc4_bo *bo = to_vc4_bo(obj);
		bo->dma_buf_import_export = true;
	}

	return obj;
}

struct dma_buf *
vc4_prime_export(struct drm_device *dev, struct drm_gem_object *obj, int flags)
{
	struct vc4_bo *bo = to_vc4_bo(obj);

	mutex_lock(&dev->struct_mutex);
	if (bo->validated_shader) {
		mutex_unlock(&dev->struct_mutex);
		DRM_ERROR("Attempting to export shader BO\n");
		return ERR_PTR(-EINVAL);
	}
	bo->dma_buf_import_export = true;
	mutex_unlock(&dev->struct_mutex);

	return drm_gem_prime_export(dev, obj, flags);
}

int
vc4_create_bo_ioctl(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	struct drm_vc4_create_bo *args = data;
	struct vc4_bo *bo = NULL;
	int ret;

	args->size = roundup(args->size, PAGE_SIZE);
	if (args->size == 0)
		return -EINVAL;

	mutex_lock(&dev->struct_mutex);
	bo = vc4_bo_create(dev, args->size);
	mutex_unlock(&dev->struct_mutex);
	if (!bo)
		return -ENOMEM;

	ret = drm_gem_handle_create(file_priv, &bo->base.base, &args->handle);
	drm_gem_object_unreference_unlocked(&bo->base.base);

	return ret;
}

int
vc4_mmap_bo_ioctl(struct drm_device *dev, void *data,
		  struct drm_file *file_priv)
{
	struct drm_vc4_mmap_bo *args = data;
	struct drm_gem_object *gem_obj;

	gem_obj = drm_gem_object_lookup(dev, file_priv, args->handle);
	if (!gem_obj) {
		DRM_ERROR("Failed to look up GEM BO %d\n", args->handle);
		return -EINVAL;
	}

	/* The mmap offset was set up at BO allocation time. */
	args->offset = drm_vma_node_offset_addr(&gem_obj->vma_node);

	drm_gem_object_unreference(gem_obj);
	return 0;
}

#ifdef CONFIG_DEBUG_FS
int vc4_bo_stats_debugfs(struct seq_file *m, void *unused)
{
	struct drm_info_node *node = (struct drm_info_node *) m->private;
	struct drm_device *dev = node->minor->dev;

	mutex_lock(&dev->struct_mutex);

	seq_printf(m, "num bos allocated: %d\n",
		   bo_stats.num_allocated);
	seq_printf(m, "size bos allocated: %dkb\n",
		   bo_stats.size_allocated / 1024);
	seq_printf(m, "num bos used: %d\n",
		   bo_stats.num_allocated - bo_stats.num_cached);
	seq_printf(m, "size bos used: %dkb\n",
		   (bo_stats.size_allocated - bo_stats.size_cached) / 1024);
	seq_printf(m, "num bos cached: %d\n",
		   bo_stats.num_cached);
	seq_printf(m, "size bos cached: %dkb\n",
		   bo_stats.size_cached / 1024);

	mutex_unlock(&dev->struct_mutex);

	return 0;
}
#endif