diff mbox series

[v4,05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers

Message ID 20201015123806.32416-6-tzimmermann@suse.de
State Superseded
Headers show
Series Support GEM object mappings from I/O memory | expand

Commit Message

Thomas Zimmermann Oct. 15, 2020, 12:38 p.m. UTC
The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
address space. The mapping's address is returned as struct dma_buf_map.
Each function is a simplified version of TTM's existing kmap code. Both
functions respect the memory's location ani/or writecombine flags.

On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
two helpers that convert a GEM object into the TTM BO and forward the call
to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM object
callbacks.

v4:
	* drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
	  Christian)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
 drivers/gpu/drm/ttm/ttm_bo_util.c    | 72 ++++++++++++++++++++++++++++
 include/drm/drm_gem_ttm_helper.h     |  6 +++
 include/drm/ttm/ttm_bo_api.h         | 28 +++++++++++
 include/linux/dma-buf-map.h          | 20 ++++++++
 5 files changed, 164 insertions(+)

Comments

Daniel Vetter Oct. 15, 2020, 4:49 p.m. UTC | #1
On Thu, Oct 15, 2020 at 04:08:13PM +0200, Christian König wrote:
> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
> > The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
> > address space. The mapping's address is returned as struct dma_buf_map.
> > Each function is a simplified version of TTM's existing kmap code. Both
> > functions respect the memory's location ani/or writecombine flags.
> > 
> > On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
> > two helpers that convert a GEM object into the TTM BO and forward the call
> > to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM object
> > callbacks.
> > 
> > v4:
> > 	* drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
> > 	  Christian)
> 
> Bunch of minor comments below, but over all look very solid to me.

Yeah I think just duplicating the ttm bo map stuff for vmap is indeed the
cleanest. And then we can maybe push the combinatorial monster into
vmwgfx, which I think is the only user after this series. Or perhaps a
dedicated set of helpers to map an invidual page (again using the
dma_buf_map stuff).

I'll let Christian with the details, but at a high level this is
definitely

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Thanks a lot for doing all this.
-Daniel

> 
> > 
> > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> > ---
> >   drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
> >   drivers/gpu/drm/ttm/ttm_bo_util.c    | 72 ++++++++++++++++++++++++++++
> >   include/drm/drm_gem_ttm_helper.h     |  6 +++
> >   include/drm/ttm/ttm_bo_api.h         | 28 +++++++++++
> >   include/linux/dma-buf-map.h          | 20 ++++++++
> >   5 files changed, 164 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
> > index 0e4fb9ba43ad..db4c14d78a30 100644
> > --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> > @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> >   }
> >   EXPORT_SYMBOL(drm_gem_ttm_print_info);
> > +/**
> > + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: [out] returns the dma-buf mapping.
> > + *
> > + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + *
> > + * Returns:
> > + * 0 on success, or a negative errno code otherwise.
> > + */
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > +		     struct dma_buf_map *map)
> > +{
> > +	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > +	return ttm_bo_vmap(bo, map);
> > +
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vmap);
> > +
> > +/**
> > + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: dma-buf mapping.
> > + *
> > + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + */
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > +			struct dma_buf_map *map)
> > +{
> > +	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > +	ttm_bo_vunmap(bo, map);
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
> > +
> >   /**
> >    * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
> >    * @gem: GEM object.
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > index bdee4df1f3f2..80c42c774c7d 100644
> > --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > @@ -32,6 +32,7 @@
> >   #include <drm/ttm/ttm_bo_driver.h>
> >   #include <drm/ttm/ttm_placement.h>
> >   #include <drm/drm_vma_manager.h>
> > +#include <linux/dma-buf-map.h>
> >   #include <linux/io.h>
> >   #include <linux/highmem.h>
> >   #include <linux/wait.h>
> > @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
> >   }
> >   EXPORT_SYMBOL(ttm_bo_kunmap);
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > +	struct ttm_resource *mem = &bo->mem;
> > +	int ret;
> > +
> > +	ret = ttm_mem_io_reserve(bo->bdev, mem);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (mem->bus.is_iomem) {
> > +		void __iomem *vaddr_iomem;
> > +		unsigned long size = bo->num_pages << PAGE_SHIFT;
> 
> Please use uint64_t here and make sure to cast bo->num_pages before
> shifting.
> 
> We have an unit tests of allocating a 8GB BO and that should work on a 32bit
> machine as well :)
> 
> > +
> > +		if (mem->bus.addr)
> > +			vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> > +		else if (mem->placement & TTM_PL_FLAG_WC)
> 
> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
> mem->bus.caching enum as replacement.
> 
> > +			vaddr_iomem = ioremap_wc(mem->bus.offset, size);
> > +		else
> > +			vaddr_iomem = ioremap(mem->bus.offset, size);
> > +
> > +		if (!vaddr_iomem)
> > +			return -ENOMEM;
> > +
> > +		dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
> > +
> > +	} else {
> > +		struct ttm_operation_ctx ctx = {
> > +			.interruptible = false,
> > +			.no_wait_gpu = false
> > +		};
> > +		struct ttm_tt *ttm = bo->ttm;
> > +		pgprot_t prot;
> > +		void *vaddr;
> > +
> > +		BUG_ON(!ttm);
> 
> I think we can drop this, populate will just crash badly anyway.
> 
> > +
> > +		ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > +		if (ret)
> > +			return ret;
> > +
> > +		/*
> > +		 * We need to use vmap to get the desired page protection
> > +		 * or to make the buffer object look contiguous.
> > +		 */
> > +		prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
> 
> The calling convention has changed on drm-misc-next as well, but should be
> trivial to adapt.
> 
> Regards,
> Christian.
> 
> > +		vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
> > +		if (!vaddr)
> > +			return -ENOMEM;
> > +
> > +		dma_buf_map_set_vaddr(map, vaddr);
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vmap);
> > +
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > +	if (dma_buf_map_is_null(map))
> > +		return;
> > +
> > +	if (map->is_iomem)
> > +		iounmap(map->vaddr_iomem);
> > +	else
> > +		vunmap(map->vaddr);
> > +	dma_buf_map_clear(map);
> > +
> > +	ttm_mem_io_free(bo->bdev, &bo->mem);
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vunmap);
> > +
> >   static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
> >   				 bool dst_use_tt)
> >   {
> > diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
> > index 118cef76f84f..7c6d874910b8 100644
> > --- a/include/drm/drm_gem_ttm_helper.h
> > +++ b/include/drm/drm_gem_ttm_helper.h
> > @@ -10,11 +10,17 @@
> >   #include <drm/ttm/ttm_bo_api.h>
> >   #include <drm/ttm/ttm_bo_driver.h>
> > +struct dma_buf_map;
> > +
> >   #define drm_gem_ttm_of_gem(gem_obj) \
> >   	container_of(gem_obj, struct ttm_buffer_object, base)
> >   void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> >   			    const struct drm_gem_object *gem);
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > +		     struct dma_buf_map *map);
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > +			struct dma_buf_map *map);
> >   int drm_gem_ttm_mmap(struct drm_gem_object *gem,
> >   		     struct vm_area_struct *vma);
> > diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> > index 37102e45e496..2c59a785374c 100644
> > --- a/include/drm/ttm/ttm_bo_api.h
> > +++ b/include/drm/ttm/ttm_bo_api.h
> > @@ -48,6 +48,8 @@ struct ttm_bo_global;
> >   struct ttm_bo_device;
> > +struct dma_buf_map;
> > +
> >   struct drm_mm_node;
> >   struct ttm_placement;
> > @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
> >    */
> >   void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
> > +/**
> > + * ttm_bo_vmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: pointer to a struct dma_buf_map representing the map.
> > + *
> > + * Sets up a kernel virtual mapping, using ioremap or vmap to the
> > + * data in the buffer object. The parameter @map returns the virtual
> > + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
> > + *
> > + * Returns
> > + * -ENOMEM: Out of memory.
> > + * -EINVAL: Invalid range.
> > + */
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > +
> > +/**
> > + * ttm_bo_vunmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: Object describing the map to unmap.
> > + *
> > + * Unmaps a kernel map set up by ttm_bo_vmap().
> > + */
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > +
> >   /**
> >    * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
> >    *
> > diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> > index fd1aba545fdf..2e8bbecb5091 100644
> > --- a/include/linux/dma-buf-map.h
> > +++ b/include/linux/dma-buf-map.h
> > @@ -45,6 +45,12 @@
> >    *
> >    *	dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
> >    *
> > + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> > + *
> > + * .. code-block:: c
> > + *
> > + *	dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> > + *
> >    * Test if a mapping is valid with either dma_buf_map_is_set() or
> >    * dma_buf_map_is_null().
> >    *
> > @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
> >   	map->is_iomem = false;
> >   }
> > +/**
> > + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
> > + * @map:		The dma-buf mapping structure
> > + * @vaddr_iomem:	An I/O-memory address
> > + *
> > + * Sets the address and the I/O-memory flag.
> > + */
> > +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> > +					       void __iomem *vaddr_iomem)
> > +{
> > +	map->vaddr_iomem = vaddr_iomem;
> > +	map->is_iomem = true;
> > +}
> > +
> >   /**
> >    * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
> >    * @lhs:	The dma-buf mapping structure
>
Thomas Zimmermann Oct. 15, 2020, 5:56 p.m. UTC | #2
Hi

On Thu, 15 Oct 2020 16:08:13 +0200 Christian König <christian.koenig@amd.com>
wrote:

> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:
> > The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel
> > address space. The mapping's address is returned as struct dma_buf_map.
> > Each function is a simplified version of TTM's existing kmap code. Both
> > functions respect the memory's location ani/or writecombine flags.
> >
> > On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),
> > two helpers that convert a GEM object into the TTM BO and forward the call
> > to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM object
> > callbacks.
> >
> > v4:
> > 	* drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,
> > 	  Christian)
> 
> Bunch of minor comments below, but over all look very solid to me.
> 
> >
> > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> > ---
> >   drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++
> >   drivers/gpu/drm/ttm/ttm_bo_util.c    | 72 ++++++++++++++++++++++++++++
> >   include/drm/drm_gem_ttm_helper.h     |  6 +++
> >   include/drm/ttm/ttm_bo_api.h         | 28 +++++++++++
> >   include/linux/dma-buf-map.h          | 20 ++++++++
> >   5 files changed, 164 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > b/drivers/gpu/drm/drm_gem_ttm_helper.c index 0e4fb9ba43ad..db4c14d78a30
> > 100644 --- a/drivers/gpu/drm/drm_gem_ttm_helper.c
> > +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
> > @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p,
> > unsigned int indent, }
> >   EXPORT_SYMBOL(drm_gem_ttm_print_info);
> >   
> > +/**
> > + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: [out] returns the dma-buf mapping.
> > + *
> > + * Maps a GEM object with ttm_bo_vmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + *
> > + * Returns:
> > + * 0 on success, or a negative errno code otherwise.
> > + */
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > +		     struct dma_buf_map *map)
> > +{
> > +	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > +	return ttm_bo_vmap(bo, map);
> > +
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vmap);
> > +
> > +/**
> > + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
> > + * @gem: GEM object.
> > + * @map: dma-buf mapping.
> > + *
> > + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used as
> > + * &drm_gem_object_funcs.vmap callback.
> > + */
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > +			struct dma_buf_map *map)
> > +{
> > +	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
> > +
> > +	ttm_bo_vunmap(bo, map);
> > +}
> > +EXPORT_SYMBOL(drm_gem_ttm_vunmap);
> > +
> >   /**
> >    * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
> >    * @gem: GEM object.
> > diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > b/drivers/gpu/drm/ttm/ttm_bo_util.c index bdee4df1f3f2..80c42c774c7d
> > 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
> > +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
> > @@ -32,6 +32,7 @@
> >   #include <drm/ttm/ttm_bo_driver.h>
> >   #include <drm/ttm/ttm_placement.h>
> >   #include <drm/drm_vma_manager.h>
> > +#include <linux/dma-buf-map.h>
> >   #include <linux/io.h>
> >   #include <linux/highmem.h>
> >   #include <linux/wait.h>
> > @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
> >   }
> >   EXPORT_SYMBOL(ttm_bo_kunmap);
> >   
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > +	struct ttm_resource *mem = &bo->mem;
> > +	int ret;
> > +
> > +	ret = ttm_mem_io_reserve(bo->bdev, mem);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (mem->bus.is_iomem) {
> > +		void __iomem *vaddr_iomem;
> > +		unsigned long size = bo->num_pages << PAGE_SHIFT;
> 
> Please use uint64_t here and make sure to cast bo->num_pages before 
> shifting.
> 
> We have an unit tests of allocating a 8GB BO and that should work on a 
> 32bit machine as well :)
> 
> > +
> > +		if (mem->bus.addr)
> > +			vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> > +		else if (mem->placement & TTM_PL_FLAG_WC)
> 
> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new 
> mem->bus.caching enum as replacement.
> 
> > +			vaddr_iomem = ioremap_wc(mem->bus.offset, size);
> > +		else
> > +			vaddr_iomem = ioremap(mem->bus.offset, size);
> > +
> > +		if (!vaddr_iomem)
> > +			return -ENOMEM;
> > +
> > +		dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
> > +
> > +	} else {
> > +		struct ttm_operation_ctx ctx = {
> > +			.interruptible = false,
> > +			.no_wait_gpu = false
> > +		};
> > +		struct ttm_tt *ttm = bo->ttm;
> > +		pgprot_t prot;
> > +		void *vaddr;
> > +
> > +		BUG_ON(!ttm);
> 
> I think we can drop this, populate will just crash badly anyway.
> 
> > +
> > +		ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
> > +		if (ret)
> > +			return ret;
> > +
> > +		/*
> > +		 * We need to use vmap to get the desired page protection
> > +		 * or to make the buffer object look contiguous.
> > +		 */
> > +		prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
> 
> The calling convention has changed on drm-misc-next as well, but should 
> be trivial to adapt.

Thanks for quickly reviewing these patches. My drm-tip seems out of date
(last Sunday). TTM is moving fast these days and I still have to get used to
that. :)

Best regards
Thomas

> 
> Regards,
> Christian.
> 
> > +		vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
> > +		if (!vaddr)
> > +			return -ENOMEM;
> > +
> > +		dma_buf_map_set_vaddr(map, vaddr);
> > +	}
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vmap);
> > +
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
> > +{
> > +	if (dma_buf_map_is_null(map))
> > +		return;
> > +
> > +	if (map->is_iomem)
> > +		iounmap(map->vaddr_iomem);
> > +	else
> > +		vunmap(map->vaddr);
> > +	dma_buf_map_clear(map);
> > +
> > +	ttm_mem_io_free(bo->bdev, &bo->mem);
> > +}
> > +EXPORT_SYMBOL(ttm_bo_vunmap);
> > +
> >   static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
> >   				 bool dst_use_tt)
> >   {
> > diff --git a/include/drm/drm_gem_ttm_helper.h
> > b/include/drm/drm_gem_ttm_helper.h index 118cef76f84f..7c6d874910b8 100644
> > --- a/include/drm/drm_gem_ttm_helper.h
> > +++ b/include/drm/drm_gem_ttm_helper.h
> > @@ -10,11 +10,17 @@
> >   #include <drm/ttm/ttm_bo_api.h>
> >   #include <drm/ttm/ttm_bo_driver.h>
> >   
> > +struct dma_buf_map;
> > +
> >   #define drm_gem_ttm_of_gem(gem_obj) \
> >   	container_of(gem_obj, struct ttm_buffer_object, base)
> >   
> >   void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
> >   			    const struct drm_gem_object *gem);
> > +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
> > +		     struct dma_buf_map *map);
> > +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
> > +			struct dma_buf_map *map);
> >   int drm_gem_ttm_mmap(struct drm_gem_object *gem,
> >   		     struct vm_area_struct *vma);
> >   
> > diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
> > index 37102e45e496..2c59a785374c 100644
> > --- a/include/drm/ttm/ttm_bo_api.h
> > +++ b/include/drm/ttm/ttm_bo_api.h
> > @@ -48,6 +48,8 @@ struct ttm_bo_global;
> >   
> >   struct ttm_bo_device;
> >   
> > +struct dma_buf_map;
> > +
> >   struct drm_mm_node;
> >   
> >   struct ttm_placement;
> > @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
> > unsigned long start_page, */
> >   void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
> >   
> > +/**
> > + * ttm_bo_vmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: pointer to a struct dma_buf_map representing the map.
> > + *
> > + * Sets up a kernel virtual mapping, using ioremap or vmap to the
> > + * data in the buffer object. The parameter @map returns the virtual
> > + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
> > + *
> > + * Returns
> > + * -ENOMEM: Out of memory.
> > + * -EINVAL: Invalid range.
> > + */
> > +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
> > +
> > +/**
> > + * ttm_bo_vunmap
> > + *
> > + * @bo: The buffer object.
> > + * @map: Object describing the map to unmap.
> > + *
> > + * Unmaps a kernel map set up by ttm_bo_vmap().
> > + */
> > +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
> > *map); +
> >   /**
> >    * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
> >    *
> > diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
> > index fd1aba545fdf..2e8bbecb5091 100644
> > --- a/include/linux/dma-buf-map.h
> > +++ b/include/linux/dma-buf-map.h
> > @@ -45,6 +45,12 @@
> >    *
> >    *	dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
> >    *
> > + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
> > + *
> > + * .. code-block:: c
> > + *
> > + *	dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
> > + *
> >    * Test if a mapping is valid with either dma_buf_map_is_set() or
> >    * dma_buf_map_is_null().
> >    *
> > @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
> > dma_buf_map *map, void *vaddr) map->is_iomem = false;
> >   }
> >   
> > +/**
> > + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an
> > address in I/O memory
> > + * @map:		The dma-buf mapping structure
> > + * @vaddr_iomem:	An I/O-memory address
> > + *
> > + * Sets the address and the I/O-memory flag.
> > + */
> > +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
> > +					       void __iomem *vaddr_iomem)
> > +{
> > +	map->vaddr_iomem = vaddr_iomem;
> > +	map->is_iomem = true;
> > +}
> > +
> >   /**
> >    * dma_buf_map_is_equal - Compares two dma-buf mapping structures for
> > equality
> >    * @lhs:	The dma-buf mapping structure
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
Christian König Oct. 16, 2020, 9:41 a.m. UTC | #3
Am 15.10.20 um 19:52 schrieb Thomas Zimmermann:
> Hi

>

> On Thu, 15 Oct 2020 18:49:09 +0200 Daniel Vetter <daniel@ffwll.ch> wrote:

>

>> On Thu, Oct 15, 2020 at 04:08:13PM +0200, Christian König wrote:

>>> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:

>>>> The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in

>>>> kernel address space. The mapping's address is returned as struct

>>>> dma_buf_map. Each function is a simplified version of TTM's existing

>>>> kmap code. Both functions respect the memory's location ani/or

>>>> writecombine flags.

>>>>

>>>> On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),

>>>> two helpers that convert a GEM object into the TTM BO and forward the

>>>> call to TTM's vmap/vunmap. These helpers can be dropped into the rsp

>>>> GEM object callbacks.

>>>>

>>>> v4:

>>>> 	* drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers

>>>> (Daniel, Christian)

>>> Bunch of minor comments below, but over all look very solid to me.

>> Yeah I think just duplicating the ttm bo map stuff for vmap is indeed the

>> cleanest. And then we can maybe push the combinatorial monster into

>> vmwgfx, which I think is the only user after this series. Or perhaps a

>> dedicated set of helpers to map an invidual page (again using the

>> dma_buf_map stuff).

>  From a quick look, I'd say it should be possible to have the same interface

> for kmap/kunmap as for vmap/vunmap (i.e., parameters are bo and dma-buf-map).

> All mapping state can be deduced from this. And struct ttm_bo_kmap_obj can be

> killed off entirely.


Yes, that would be rather nice to have.

Thanks,
Christian.

>

> Best regards

> Thomas

>

>> I'll let Christian with the details, but at a high level this is

>> definitely

>>

>> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

>>

>> Thanks a lot for doing all this.

>> -Daniel

>>

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

>>>> ---

>>>>    drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++

>>>>    drivers/gpu/drm/ttm/ttm_bo_util.c    | 72 ++++++++++++++++++++++++++++

>>>>    include/drm/drm_gem_ttm_helper.h     |  6 +++

>>>>    include/drm/ttm/ttm_bo_api.h         | 28 +++++++++++

>>>>    include/linux/dma-buf-map.h          | 20 ++++++++

>>>>    5 files changed, 164 insertions(+)

>>>>

>>>> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c

>>>> b/drivers/gpu/drm/drm_gem_ttm_helper.c index 0e4fb9ba43ad..db4c14d78a30

>>>> 100644 --- a/drivers/gpu/drm/drm_gem_ttm_helper.c

>>>> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c

>>>> @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p,

>>>> unsigned int indent, }

>>>>    EXPORT_SYMBOL(drm_gem_ttm_print_info);

>>>> +/**

>>>> + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object

>>>> + * @gem: GEM object.

>>>> + * @map: [out] returns the dma-buf mapping.

>>>> + *

>>>> + * Maps a GEM object with ttm_bo_vmap(). This function can be used as

>>>> + * &drm_gem_object_funcs.vmap callback.

>>>> + *

>>>> + * Returns:

>>>> + * 0 on success, or a negative errno code otherwise.

>>>> + */

>>>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,

>>>> +		     struct dma_buf_map *map)

>>>> +{

>>>> +	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);

>>>> +

>>>> +	return ttm_bo_vmap(bo, map);

>>>> +

>>>> +}

>>>> +EXPORT_SYMBOL(drm_gem_ttm_vmap);

>>>> +

>>>> +/**

>>>> + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object

>>>> + * @gem: GEM object.

>>>> + * @map: dma-buf mapping.

>>>> + *

>>>> + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used

>>>> as

>>>> + * &drm_gem_object_funcs.vmap callback.

>>>> + */

>>>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,

>>>> +			struct dma_buf_map *map)

>>>> +{

>>>> +	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);

>>>> +

>>>> +	ttm_bo_vunmap(bo, map);

>>>> +}

>>>> +EXPORT_SYMBOL(drm_gem_ttm_vunmap);

>>>> +

>>>>    /**

>>>>     * drm_gem_ttm_mmap() - mmap &ttm_buffer_object

>>>>     * @gem: GEM object.

>>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c

>>>> b/drivers/gpu/drm/ttm/ttm_bo_util.c index bdee4df1f3f2..80c42c774c7d

>>>> 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c

>>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c

>>>> @@ -32,6 +32,7 @@

>>>>    #include <drm/ttm/ttm_bo_driver.h>

>>>>    #include <drm/ttm/ttm_placement.h>

>>>>    #include <drm/drm_vma_manager.h>

>>>> +#include <linux/dma-buf-map.h>

>>>>    #include <linux/io.h>

>>>>    #include <linux/highmem.h>

>>>>    #include <linux/wait.h>

>>>> @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)

>>>>    }

>>>>    EXPORT_SYMBOL(ttm_bo_kunmap);

>>>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)

>>>> +{

>>>> +	struct ttm_resource *mem = &bo->mem;

>>>> +	int ret;

>>>> +

>>>> +	ret = ttm_mem_io_reserve(bo->bdev, mem);

>>>> +	if (ret)

>>>> +		return ret;

>>>> +

>>>> +	if (mem->bus.is_iomem) {

>>>> +		void __iomem *vaddr_iomem;

>>>> +		unsigned long size = bo->num_pages << PAGE_SHIFT;

>>> Please use uint64_t here and make sure to cast bo->num_pages before

>>> shifting.

>>>

>>> We have an unit tests of allocating a 8GB BO and that should work on a

>>> 32bit machine as well :)

>>>

>>>> +

>>>> +		if (mem->bus.addr)

>>>> +			vaddr_iomem = (void *)(((u8 *)mem->bus.addr));

>>>> +		else if (mem->placement & TTM_PL_FLAG_WC)

>>> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new

>>> mem->bus.caching enum as replacement.

>>>

>>>> +			vaddr_iomem = ioremap_wc(mem->bus.offset,

>>>> size);

>>>> +		else

>>>> +			vaddr_iomem = ioremap(mem->bus.offset, size);

>>>> +

>>>> +		if (!vaddr_iomem)

>>>> +			return -ENOMEM;

>>>> +

>>>> +		dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);

>>>> +

>>>> +	} else {

>>>> +		struct ttm_operation_ctx ctx = {

>>>> +			.interruptible = false,

>>>> +			.no_wait_gpu = false

>>>> +		};

>>>> +		struct ttm_tt *ttm = bo->ttm;

>>>> +		pgprot_t prot;

>>>> +		void *vaddr;

>>>> +

>>>> +		BUG_ON(!ttm);

>>> I think we can drop this, populate will just crash badly anyway.

>>>

>>>> +

>>>> +		ret = ttm_tt_populate(bo->bdev, ttm, &ctx);

>>>> +		if (ret)

>>>> +			return ret;

>>>> +

>>>> +		/*

>>>> +		 * We need to use vmap to get the desired page

>>>> protection

>>>> +		 * or to make the buffer object look contiguous.

>>>> +		 */

>>>> +		prot = ttm_io_prot(mem->placement, PAGE_KERNEL);

>>> The calling convention has changed on drm-misc-next as well, but should be

>>> trivial to adapt.

>>>

>>> Regards,

>>> Christian.

>>>

>>>> +		vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);

>>>> +		if (!vaddr)

>>>> +			return -ENOMEM;

>>>> +

>>>> +		dma_buf_map_set_vaddr(map, vaddr);

>>>> +	}

>>>> +

>>>> +	return 0;

>>>> +}

>>>> +EXPORT_SYMBOL(ttm_bo_vmap);

>>>> +

>>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map

>>>> *map) +{

>>>> +	if (dma_buf_map_is_null(map))

>>>> +		return;

>>>> +

>>>> +	if (map->is_iomem)

>>>> +		iounmap(map->vaddr_iomem);

>>>> +	else

>>>> +		vunmap(map->vaddr);

>>>> +	dma_buf_map_clear(map);

>>>> +

>>>> +	ttm_mem_io_free(bo->bdev, &bo->mem);

>>>> +}

>>>> +EXPORT_SYMBOL(ttm_bo_vunmap);

>>>> +

>>>>    static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,

>>>>    				 bool dst_use_tt)

>>>>    {

>>>> diff --git a/include/drm/drm_gem_ttm_helper.h

>>>> b/include/drm/drm_gem_ttm_helper.h index 118cef76f84f..7c6d874910b8

>>>> 100644 --- a/include/drm/drm_gem_ttm_helper.h

>>>> +++ b/include/drm/drm_gem_ttm_helper.h

>>>> @@ -10,11 +10,17 @@

>>>>    #include <drm/ttm/ttm_bo_api.h>

>>>>    #include <drm/ttm/ttm_bo_driver.h>

>>>> +struct dma_buf_map;

>>>> +

>>>>    #define drm_gem_ttm_of_gem(gem_obj) \

>>>>    	container_of(gem_obj, struct ttm_buffer_object, base)

>>>>    void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int

>>>> indent, const struct drm_gem_object *gem);

>>>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,

>>>> +		     struct dma_buf_map *map);

>>>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,

>>>> +			struct dma_buf_map *map);

>>>>    int drm_gem_ttm_mmap(struct drm_gem_object *gem,

>>>>    		     struct vm_area_struct *vma);

>>>> diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h

>>>> index 37102e45e496..2c59a785374c 100644

>>>> --- a/include/drm/ttm/ttm_bo_api.h

>>>> +++ b/include/drm/ttm/ttm_bo_api.h

>>>> @@ -48,6 +48,8 @@ struct ttm_bo_global;

>>>>    struct ttm_bo_device;

>>>> +struct dma_buf_map;

>>>> +

>>>>    struct drm_mm_node;

>>>>    struct ttm_placement;

>>>> @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,

>>>> unsigned long start_page, */

>>>>    void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);

>>>> +/**

>>>> + * ttm_bo_vmap

>>>> + *

>>>> + * @bo: The buffer object.

>>>> + * @map: pointer to a struct dma_buf_map representing the map.

>>>> + *

>>>> + * Sets up a kernel virtual mapping, using ioremap or vmap to the

>>>> + * data in the buffer object. The parameter @map returns the virtual

>>>> + * address as struct dma_buf_map. Unmap the buffer with

>>>> ttm_bo_vunmap().

>>>> + *

>>>> + * Returns

>>>> + * -ENOMEM: Out of memory.

>>>> + * -EINVAL: Invalid range.

>>>> + */

>>>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);

>>>> +

>>>> +/**

>>>> + * ttm_bo_vunmap

>>>> + *

>>>> + * @bo: The buffer object.

>>>> + * @map: Object describing the map to unmap.

>>>> + *

>>>> + * Unmaps a kernel map set up by ttm_bo_vmap().

>>>> + */

>>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map

>>>> *map); +

>>>>    /**

>>>>     * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.

>>>>     *

>>>> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h

>>>> index fd1aba545fdf..2e8bbecb5091 100644

>>>> --- a/include/linux/dma-buf-map.h

>>>> +++ b/include/linux/dma-buf-map.h

>>>> @@ -45,6 +45,12 @@

>>>>     *

>>>>     *	dma_buf_map_set_vaddr(&map. 0xdeadbeaf);

>>>>     *

>>>> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().

>>>> + *

>>>> + * .. code-block:: c

>>>> + *

>>>> + *	dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);

>>>> + *

>>>>     * Test if a mapping is valid with either dma_buf_map_is_set() or

>>>>     * dma_buf_map_is_null().

>>>>     *

>>>> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct

>>>> dma_buf_map *map, void *vaddr) map->is_iomem = false;

>>>>    }

>>>> +/**

>>>> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to

>>>> an address in I/O memory

>>>> + * @map:		The dma-buf mapping structure

>>>> + * @vaddr_iomem:	An I/O-memory address

>>>> + *

>>>> + * Sets the address and the I/O-memory flag.

>>>> + */

>>>> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,

>>>> +					       void __iomem

>>>> *vaddr_iomem) +{

>>>> +	map->vaddr_iomem = vaddr_iomem;

>>>> +	map->is_iomem = true;

>>>> +}

>>>> +

>>>>    /**

>>>>     * dma_buf_map_is_equal - Compares two dma-buf mapping structures for

>>>> equality

>>>>     * @lhs:	The dma-buf mapping structure

>

>
Thomas Zimmermann Oct. 19, 2020, 9:08 a.m. UTC | #4
Hi Christian

On 15.10.20 16:08, Christian König wrote:
> Am 15.10.20 um 14:38 schrieb Thomas Zimmermann:

>> The new functions ttm_bo_{vmap,vunmap}() map and unmap a TTM BO in kernel

>> address space. The mapping's address is returned as struct dma_buf_map.

>> Each function is a simplified version of TTM's existing kmap code. Both

>> functions respect the memory's location ani/or writecombine flags.

>>

>> On top TTM's functions, GEM TTM helpers got drm_gem_ttm_{vmap,vunmap}(),

>> two helpers that convert a GEM object into the TTM BO and forward the

>> call

>> to TTM's vmap/vunmap. These helpers can be dropped into the rsp GEM

>> object

>> callbacks.

>>

>> v4:

>>     * drop ttm_kmap_obj_to_dma_buf() in favor of vmap helpers (Daniel,

>>       Christian)

> 

> Bunch of minor comments below, but over all look very solid to me.

> 

>>

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

>> ---

>>   drivers/gpu/drm/drm_gem_ttm_helper.c | 38 +++++++++++++++

>>   drivers/gpu/drm/ttm/ttm_bo_util.c    | 72 ++++++++++++++++++++++++++++

>>   include/drm/drm_gem_ttm_helper.h     |  6 +++

>>   include/drm/ttm/ttm_bo_api.h         | 28 +++++++++++

>>   include/linux/dma-buf-map.h          | 20 ++++++++

>>   5 files changed, 164 insertions(+)

>>

>> diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c

>> b/drivers/gpu/drm/drm_gem_ttm_helper.c

>> index 0e4fb9ba43ad..db4c14d78a30 100644

>> --- a/drivers/gpu/drm/drm_gem_ttm_helper.c

>> +++ b/drivers/gpu/drm/drm_gem_ttm_helper.c

>> @@ -49,6 +49,44 @@ void drm_gem_ttm_print_info(struct drm_printer *p,

>> unsigned int indent,

>>   }

>>   EXPORT_SYMBOL(drm_gem_ttm_print_info);

>>   +/**

>> + * drm_gem_ttm_vmap() - vmap &ttm_buffer_object

>> + * @gem: GEM object.

>> + * @map: [out] returns the dma-buf mapping.

>> + *

>> + * Maps a GEM object with ttm_bo_vmap(). This function can be used as

>> + * &drm_gem_object_funcs.vmap callback.

>> + *

>> + * Returns:

>> + * 0 on success, or a negative errno code otherwise.

>> + */

>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,

>> +             struct dma_buf_map *map)

>> +{

>> +    struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);

>> +

>> +    return ttm_bo_vmap(bo, map);

>> +

>> +}

>> +EXPORT_SYMBOL(drm_gem_ttm_vmap);

>> +

>> +/**

>> + * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object

>> + * @gem: GEM object.

>> + * @map: dma-buf mapping.

>> + *

>> + * Unmaps a GEM object with ttm_bo_vunmap(). This function can be

>> used as

>> + * &drm_gem_object_funcs.vmap callback.

>> + */

>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,

>> +            struct dma_buf_map *map)

>> +{

>> +    struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);

>> +

>> +    ttm_bo_vunmap(bo, map);

>> +}

>> +EXPORT_SYMBOL(drm_gem_ttm_vunmap);

>> +

>>   /**

>>    * drm_gem_ttm_mmap() - mmap &ttm_buffer_object

>>    * @gem: GEM object.

>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c

>> b/drivers/gpu/drm/ttm/ttm_bo_util.c

>> index bdee4df1f3f2..80c42c774c7d 100644

>> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c

>> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c

>> @@ -32,6 +32,7 @@

>>   #include <drm/ttm/ttm_bo_driver.h>

>>   #include <drm/ttm/ttm_placement.h>

>>   #include <drm/drm_vma_manager.h>

>> +#include <linux/dma-buf-map.h>

>>   #include <linux/io.h>

>>   #include <linux/highmem.h>

>>   #include <linux/wait.h>

>> @@ -526,6 +527,77 @@ void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)

>>   }

>>   EXPORT_SYMBOL(ttm_bo_kunmap);

>>   +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)

>> +{

>> +    struct ttm_resource *mem = &bo->mem;

>> +    int ret;

>> +

>> +    ret = ttm_mem_io_reserve(bo->bdev, mem);

>> +    if (ret)

>> +        return ret;

>> +

>> +    if (mem->bus.is_iomem) {

>> +        void __iomem *vaddr_iomem;

>> +        unsigned long size = bo->num_pages << PAGE_SHIFT;

> 

> Please use uint64_t here and make sure to cast bo->num_pages before

> shifting.


I thought the rule of thumb is to use u64 in source code. Yet TTM only
uses uint*_t types. Is there anything special about TTM?

> 

> We have an unit tests of allocating a 8GB BO and that should work on a

> 32bit machine as well :)

> 

>> +

>> +        if (mem->bus.addr)

>> +            vaddr_iomem = (void *)(((u8 *)mem->bus.addr));


I after reading the patch again, I realized that this is the
'ttm_bo_map_premapped' case and it's missing from _vunmap(). I see two
options here: ignore this case in _vunmap(), or do an ioremap()
unconditionally. Which one is preferable?

Best regards
Thomas

>> +        else if (mem->placement & TTM_PL_FLAG_WC)

> 

> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new

> mem->bus.caching enum as replacement.

> 

>> +            vaddr_iomem = ioremap_wc(mem->bus.offset, size);

>> +        else

>> +            vaddr_iomem = ioremap(mem->bus.offset, size);

>> +

>> +        if (!vaddr_iomem)

>> +            return -ENOMEM;

>> +

>> +        dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);

>> +

>> +    } else {

>> +        struct ttm_operation_ctx ctx = {

>> +            .interruptible = false,

>> +            .no_wait_gpu = false

>> +        };

>> +        struct ttm_tt *ttm = bo->ttm;

>> +        pgprot_t prot;

>> +        void *vaddr;

>> +

>> +        BUG_ON(!ttm);

> 

> I think we can drop this, populate will just crash badly anyway.

> 

>> +

>> +        ret = ttm_tt_populate(bo->bdev, ttm, &ctx);

>> +        if (ret)

>> +            return ret;

>> +

>> +        /*

>> +         * We need to use vmap to get the desired page protection

>> +         * or to make the buffer object look contiguous.

>> +         */

>> +        prot = ttm_io_prot(mem->placement, PAGE_KERNEL);

> 

> The calling convention has changed on drm-misc-next as well, but should

> be trivial to adapt.

> 

> Regards,

> Christian.

> 

>> +        vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);

>> +        if (!vaddr)

>> +            return -ENOMEM;

>> +

>> +        dma_buf_map_set_vaddr(map, vaddr);

>> +    }

>> +

>> +    return 0;

>> +}

>> +EXPORT_SYMBOL(ttm_bo_vmap);

>> +

>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map

>> *map)

>> +{

>> +    if (dma_buf_map_is_null(map))

>> +        return;

>> +

>> +    if (map->is_iomem)

>> +        iounmap(map->vaddr_iomem);

>> +    else

>> +        vunmap(map->vaddr);

>> +    dma_buf_map_clear(map);

>> +

>> +    ttm_mem_io_free(bo->bdev, &bo->mem);

>> +}

>> +EXPORT_SYMBOL(ttm_bo_vunmap);

>> +

>>   static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,

>>                    bool dst_use_tt)

>>   {

>> diff --git a/include/drm/drm_gem_ttm_helper.h

>> b/include/drm/drm_gem_ttm_helper.h

>> index 118cef76f84f..7c6d874910b8 100644

>> --- a/include/drm/drm_gem_ttm_helper.h

>> +++ b/include/drm/drm_gem_ttm_helper.h

>> @@ -10,11 +10,17 @@

>>   #include <drm/ttm/ttm_bo_api.h>

>>   #include <drm/ttm/ttm_bo_driver.h>

>>   +struct dma_buf_map;

>> +

>>   #define drm_gem_ttm_of_gem(gem_obj) \

>>       container_of(gem_obj, struct ttm_buffer_object, base)

>>     void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int

>> indent,

>>                   const struct drm_gem_object *gem);

>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,

>> +             struct dma_buf_map *map);

>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,

>> +            struct dma_buf_map *map);

>>   int drm_gem_ttm_mmap(struct drm_gem_object *gem,

>>                struct vm_area_struct *vma);

>>   diff --git a/include/drm/ttm/ttm_bo_api.h

>> b/include/drm/ttm/ttm_bo_api.h

>> index 37102e45e496..2c59a785374c 100644

>> --- a/include/drm/ttm/ttm_bo_api.h

>> +++ b/include/drm/ttm/ttm_bo_api.h

>> @@ -48,6 +48,8 @@ struct ttm_bo_global;

>>     struct ttm_bo_device;

>>   +struct dma_buf_map;

>> +

>>   struct drm_mm_node;

>>     struct ttm_placement;

>> @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,

>> unsigned long start_page,

>>    */

>>   void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);

>>   +/**

>> + * ttm_bo_vmap

>> + *

>> + * @bo: The buffer object.

>> + * @map: pointer to a struct dma_buf_map representing the map.

>> + *

>> + * Sets up a kernel virtual mapping, using ioremap or vmap to the

>> + * data in the buffer object. The parameter @map returns the virtual

>> + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().

>> + *

>> + * Returns

>> + * -ENOMEM: Out of memory.

>> + * -EINVAL: Invalid range.

>> + */

>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);

>> +

>> +/**

>> + * ttm_bo_vunmap

>> + *

>> + * @bo: The buffer object.

>> + * @map: Object describing the map to unmap.

>> + *

>> + * Unmaps a kernel map set up by ttm_bo_vmap().

>> + */

>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map

>> *map);

>> +

>>   /**

>>    * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.

>>    *

>> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h

>> index fd1aba545fdf..2e8bbecb5091 100644

>> --- a/include/linux/dma-buf-map.h

>> +++ b/include/linux/dma-buf-map.h

>> @@ -45,6 +45,12 @@

>>    *

>>    *    dma_buf_map_set_vaddr(&map. 0xdeadbeaf);

>>    *

>> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().

>> + *

>> + * .. code-block:: c

>> + *

>> + *    dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);

>> + *

>>    * Test if a mapping is valid with either dma_buf_map_is_set() or

>>    * dma_buf_map_is_null().

>>    *

>> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct

>> dma_buf_map *map, void *vaddr)

>>       map->is_iomem = false;

>>   }

>>   +/**

>> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to

>> an address in I/O memory

>> + * @map:        The dma-buf mapping structure

>> + * @vaddr_iomem:    An I/O-memory address

>> + *

>> + * Sets the address and the I/O-memory flag.

>> + */

>> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,

>> +                           void __iomem *vaddr_iomem)

>> +{

>> +    map->vaddr_iomem = vaddr_iomem;

>> +    map->is_iomem = true;

>> +}

>> +

>>   /**

>>    * dma_buf_map_is_equal - Compares two dma-buf mapping structures

>> for equality

>>    * @lhs:    The dma-buf mapping structure

> 

> _______________________________________________

> dri-devel mailing list

> dri-devel@lists.freedesktop.org

> https://lists.freedesktop.org/mailman/listinfo/dri-devel


-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer
Christian König Oct. 19, 2020, 9:45 a.m. UTC | #5
Hi Thomas,

[SNIP]
>>>    +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
>>> +{
>>> +    struct ttm_resource *mem = &bo->mem;
>>> +    int ret;
>>> +
>>> +    ret = ttm_mem_io_reserve(bo->bdev, mem);
>>> +    if (ret)
>>> +        return ret;
>>> +
>>> +    if (mem->bus.is_iomem) {
>>> +        void __iomem *vaddr_iomem;
>>> +        unsigned long size = bo->num_pages << PAGE_SHIFT;
>> Please use uint64_t here and make sure to cast bo->num_pages before
>> shifting.
> I thought the rule of thumb is to use u64 in source code. Yet TTM only
> uses uint*_t types. Is there anything special about TTM?

My last status is that you can use both and my personal preference is to 
use the uint*_t types because they are part of a higher level standard.

>> We have an unit tests of allocating a 8GB BO and that should work on a
>> 32bit machine as well :)
>>
>>> +
>>> +        if (mem->bus.addr)
>>> +            vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
> I after reading the patch again, I realized that this is the
> 'ttm_bo_map_premapped' case and it's missing from _vunmap(). I see two
> options here: ignore this case in _vunmap(), or do an ioremap()
> unconditionally. Which one is preferable?

ioremap would be very very bad, so we should just do nothing.

Thanks,
Christian.

>
> Best regards
> Thomas
>
>>> +        else if (mem->placement & TTM_PL_FLAG_WC)
>> I've just nuked the TTM_PL_FLAG_WC flag in drm-misc-next. There is a new
>> mem->bus.caching enum as replacement.
>>
>>> +            vaddr_iomem = ioremap_wc(mem->bus.offset, size);
>>> +        else
>>> +            vaddr_iomem = ioremap(mem->bus.offset, size);
>>> +
>>> +        if (!vaddr_iomem)
>>> +            return -ENOMEM;
>>> +
>>> +        dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
>>> +
>>> +    } else {
>>> +        struct ttm_operation_ctx ctx = {
>>> +            .interruptible = false,
>>> +            .no_wait_gpu = false
>>> +        };
>>> +        struct ttm_tt *ttm = bo->ttm;
>>> +        pgprot_t prot;
>>> +        void *vaddr;
>>> +
>>> +        BUG_ON(!ttm);
>> I think we can drop this, populate will just crash badly anyway.
>>
>>> +
>>> +        ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
>>> +        if (ret)
>>> +            return ret;
>>> +
>>> +        /*
>>> +         * We need to use vmap to get the desired page protection
>>> +         * or to make the buffer object look contiguous.
>>> +         */
>>> +        prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
>> The calling convention has changed on drm-misc-next as well, but should
>> be trivial to adapt.
>>
>> Regards,
>> Christian.
>>
>>> +        vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
>>> +        if (!vaddr)
>>> +            return -ENOMEM;
>>> +
>>> +        dma_buf_map_set_vaddr(map, vaddr);
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +EXPORT_SYMBOL(ttm_bo_vmap);
>>> +
>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>>> *map)
>>> +{
>>> +    if (dma_buf_map_is_null(map))
>>> +        return;
>>> +
>>> +    if (map->is_iomem)
>>> +        iounmap(map->vaddr_iomem);
>>> +    else
>>> +        vunmap(map->vaddr);
>>> +    dma_buf_map_clear(map);
>>> +
>>> +    ttm_mem_io_free(bo->bdev, &bo->mem);
>>> +}
>>> +EXPORT_SYMBOL(ttm_bo_vunmap);
>>> +
>>>    static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
>>>                     bool dst_use_tt)
>>>    {
>>> diff --git a/include/drm/drm_gem_ttm_helper.h
>>> b/include/drm/drm_gem_ttm_helper.h
>>> index 118cef76f84f..7c6d874910b8 100644
>>> --- a/include/drm/drm_gem_ttm_helper.h
>>> +++ b/include/drm/drm_gem_ttm_helper.h
>>> @@ -10,11 +10,17 @@
>>>    #include <drm/ttm/ttm_bo_api.h>
>>>    #include <drm/ttm/ttm_bo_driver.h>
>>>    +struct dma_buf_map;
>>> +
>>>    #define drm_gem_ttm_of_gem(gem_obj) \
>>>        container_of(gem_obj, struct ttm_buffer_object, base)
>>>      void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int
>>> indent,
>>>                    const struct drm_gem_object *gem);
>>> +int drm_gem_ttm_vmap(struct drm_gem_object *gem,
>>> +             struct dma_buf_map *map);
>>> +void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
>>> +            struct dma_buf_map *map);
>>>    int drm_gem_ttm_mmap(struct drm_gem_object *gem,
>>>                 struct vm_area_struct *vma);
>>>    diff --git a/include/drm/ttm/ttm_bo_api.h
>>> b/include/drm/ttm/ttm_bo_api.h
>>> index 37102e45e496..2c59a785374c 100644
>>> --- a/include/drm/ttm/ttm_bo_api.h
>>> +++ b/include/drm/ttm/ttm_bo_api.h
>>> @@ -48,6 +48,8 @@ struct ttm_bo_global;
>>>      struct ttm_bo_device;
>>>    +struct dma_buf_map;
>>> +
>>>    struct drm_mm_node;
>>>      struct ttm_placement;
>>> @@ -494,6 +496,32 @@ int ttm_bo_kmap(struct ttm_buffer_object *bo,
>>> unsigned long start_page,
>>>     */
>>>    void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
>>>    +/**
>>> + * ttm_bo_vmap
>>> + *
>>> + * @bo: The buffer object.
>>> + * @map: pointer to a struct dma_buf_map representing the map.
>>> + *
>>> + * Sets up a kernel virtual mapping, using ioremap or vmap to the
>>> + * data in the buffer object. The parameter @map returns the virtual
>>> + * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
>>> + *
>>> + * Returns
>>> + * -ENOMEM: Out of memory.
>>> + * -EINVAL: Invalid range.
>>> + */
>>> +int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
>>> +
>>> +/**
>>> + * ttm_bo_vunmap
>>> + *
>>> + * @bo: The buffer object.
>>> + * @map: Object describing the map to unmap.
>>> + *
>>> + * Unmaps a kernel map set up by ttm_bo_vmap().
>>> + */
>>> +void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map
>>> *map);
>>> +
>>>    /**
>>>     * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
>>>     *
>>> diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
>>> index fd1aba545fdf..2e8bbecb5091 100644
>>> --- a/include/linux/dma-buf-map.h
>>> +++ b/include/linux/dma-buf-map.h
>>> @@ -45,6 +45,12 @@
>>>     *
>>>     *    dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
>>>     *
>>> + * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
>>> + *
>>> + * .. code-block:: c
>>> + *
>>> + *    dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
>>> + *
>>>     * Test if a mapping is valid with either dma_buf_map_is_set() or
>>>     * dma_buf_map_is_null().
>>>     *
>>> @@ -118,6 +124,20 @@ static inline void dma_buf_map_set_vaddr(struct
>>> dma_buf_map *map, void *vaddr)
>>>        map->is_iomem = false;
>>>    }
>>>    +/**
>>> + * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to
>>> an address in I/O memory
>>> + * @map:        The dma-buf mapping structure
>>> + * @vaddr_iomem:    An I/O-memory address
>>> + *
>>> + * Sets the address and the I/O-memory flag.
>>> + */
>>> +static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
>>> +                           void __iomem *vaddr_iomem)
>>> +{
>>> +    map->vaddr_iomem = vaddr_iomem;
>>> +    map->is_iomem = true;
>>> +}
>>> +
>>>    /**
>>>     * dma_buf_map_is_equal - Compares two dma-buf mapping structures
>>> for equality
>>>     * @lhs:    The dma-buf mapping structure
>> _______________________________________________
>> dri-devel mailing list
>> dri-devel@lists.freedesktop.org
>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fdri-devel&amp;data=04%7C01%7Cchristian.koenig%40amd.com%7C07bc68af3c6440b5be8d08d8740e9b32%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637386953433558595%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=RlGCmjzyZERvqfnl4kA1bEHez5bkLf3F9OlKi2ybDAM%3D&amp;reserved=0
diff mbox series

Patch

diff --git a/drivers/gpu/drm/drm_gem_ttm_helper.c b/drivers/gpu/drm/drm_gem_ttm_helper.c
index 0e4fb9ba43ad..db4c14d78a30 100644
--- a/drivers/gpu/drm/drm_gem_ttm_helper.c
+++ b/drivers/gpu/drm/drm_gem_ttm_helper.c
@@ -49,6 +49,44 @@  void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
 }
 EXPORT_SYMBOL(drm_gem_ttm_print_info);
 
+/**
+ * drm_gem_ttm_vmap() - vmap &ttm_buffer_object
+ * @gem: GEM object.
+ * @map: [out] returns the dma-buf mapping.
+ *
+ * Maps a GEM object with ttm_bo_vmap(). This function can be used as
+ * &drm_gem_object_funcs.vmap callback.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int drm_gem_ttm_vmap(struct drm_gem_object *gem,
+		     struct dma_buf_map *map)
+{
+	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
+
+	return ttm_bo_vmap(bo, map);
+
+}
+EXPORT_SYMBOL(drm_gem_ttm_vmap);
+
+/**
+ * drm_gem_ttm_vunmap() - vunmap &ttm_buffer_object
+ * @gem: GEM object.
+ * @map: dma-buf mapping.
+ *
+ * Unmaps a GEM object with ttm_bo_vunmap(). This function can be used as
+ * &drm_gem_object_funcs.vmap callback.
+ */
+void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
+			struct dma_buf_map *map)
+{
+	struct ttm_buffer_object *bo = drm_gem_ttm_of_gem(gem);
+
+	ttm_bo_vunmap(bo, map);
+}
+EXPORT_SYMBOL(drm_gem_ttm_vunmap);
+
 /**
  * drm_gem_ttm_mmap() - mmap &ttm_buffer_object
  * @gem: GEM object.
diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
index bdee4df1f3f2..80c42c774c7d 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_util.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
@@ -32,6 +32,7 @@ 
 #include <drm/ttm/ttm_bo_driver.h>
 #include <drm/ttm/ttm_placement.h>
 #include <drm/drm_vma_manager.h>
+#include <linux/dma-buf-map.h>
 #include <linux/io.h>
 #include <linux/highmem.h>
 #include <linux/wait.h>
@@ -526,6 +527,77 @@  void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map)
 }
 EXPORT_SYMBOL(ttm_bo_kunmap);
 
+int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
+{
+	struct ttm_resource *mem = &bo->mem;
+	int ret;
+
+	ret = ttm_mem_io_reserve(bo->bdev, mem);
+	if (ret)
+		return ret;
+
+	if (mem->bus.is_iomem) {
+		void __iomem *vaddr_iomem;
+		unsigned long size = bo->num_pages << PAGE_SHIFT;
+
+		if (mem->bus.addr)
+			vaddr_iomem = (void *)(((u8 *)mem->bus.addr));
+		else if (mem->placement & TTM_PL_FLAG_WC)
+			vaddr_iomem = ioremap_wc(mem->bus.offset, size);
+		else
+			vaddr_iomem = ioremap(mem->bus.offset, size);
+
+		if (!vaddr_iomem)
+			return -ENOMEM;
+
+		dma_buf_map_set_vaddr_iomem(map, vaddr_iomem);
+
+	} else {
+		struct ttm_operation_ctx ctx = {
+			.interruptible = false,
+			.no_wait_gpu = false
+		};
+		struct ttm_tt *ttm = bo->ttm;
+		pgprot_t prot;
+		void *vaddr;
+
+		BUG_ON(!ttm);
+
+		ret = ttm_tt_populate(bo->bdev, ttm, &ctx);
+		if (ret)
+			return ret;
+
+		/*
+		 * We need to use vmap to get the desired page protection
+		 * or to make the buffer object look contiguous.
+		 */
+		prot = ttm_io_prot(mem->placement, PAGE_KERNEL);
+		vaddr = vmap(ttm->pages, bo->num_pages, 0, prot);
+		if (!vaddr)
+			return -ENOMEM;
+
+		dma_buf_map_set_vaddr(map, vaddr);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(ttm_bo_vmap);
+
+void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map)
+{
+	if (dma_buf_map_is_null(map))
+		return;
+
+	if (map->is_iomem)
+		iounmap(map->vaddr_iomem);
+	else
+		vunmap(map->vaddr);
+	dma_buf_map_clear(map);
+
+	ttm_mem_io_free(bo->bdev, &bo->mem);
+}
+EXPORT_SYMBOL(ttm_bo_vunmap);
+
 static int ttm_bo_wait_free_node(struct ttm_buffer_object *bo,
 				 bool dst_use_tt)
 {
diff --git a/include/drm/drm_gem_ttm_helper.h b/include/drm/drm_gem_ttm_helper.h
index 118cef76f84f..7c6d874910b8 100644
--- a/include/drm/drm_gem_ttm_helper.h
+++ b/include/drm/drm_gem_ttm_helper.h
@@ -10,11 +10,17 @@ 
 #include <drm/ttm/ttm_bo_api.h>
 #include <drm/ttm/ttm_bo_driver.h>
 
+struct dma_buf_map;
+
 #define drm_gem_ttm_of_gem(gem_obj) \
 	container_of(gem_obj, struct ttm_buffer_object, base)
 
 void drm_gem_ttm_print_info(struct drm_printer *p, unsigned int indent,
 			    const struct drm_gem_object *gem);
+int drm_gem_ttm_vmap(struct drm_gem_object *gem,
+		     struct dma_buf_map *map);
+void drm_gem_ttm_vunmap(struct drm_gem_object *gem,
+			struct dma_buf_map *map);
 int drm_gem_ttm_mmap(struct drm_gem_object *gem,
 		     struct vm_area_struct *vma);
 
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index 37102e45e496..2c59a785374c 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -48,6 +48,8 @@  struct ttm_bo_global;
 
 struct ttm_bo_device;
 
+struct dma_buf_map;
+
 struct drm_mm_node;
 
 struct ttm_placement;
@@ -494,6 +496,32 @@  int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
  */
 void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
 
+/**
+ * ttm_bo_vmap
+ *
+ * @bo: The buffer object.
+ * @map: pointer to a struct dma_buf_map representing the map.
+ *
+ * Sets up a kernel virtual mapping, using ioremap or vmap to the
+ * data in the buffer object. The parameter @map returns the virtual
+ * address as struct dma_buf_map. Unmap the buffer with ttm_bo_vunmap().
+ *
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid range.
+ */
+int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
+
+/**
+ * ttm_bo_vunmap
+ *
+ * @bo: The buffer object.
+ * @map: Object describing the map to unmap.
+ *
+ * Unmaps a kernel map set up by ttm_bo_vmap().
+ */
+void ttm_bo_vunmap(struct ttm_buffer_object *bo, struct dma_buf_map *map);
+
 /**
  * ttm_bo_mmap_obj - mmap memory backed by a ttm buffer object.
  *
diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
index fd1aba545fdf..2e8bbecb5091 100644
--- a/include/linux/dma-buf-map.h
+++ b/include/linux/dma-buf-map.h
@@ -45,6 +45,12 @@ 
  *
  *	dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
  *
+ * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
+ *
+ * .. code-block:: c
+ *
+ *	dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
+ *
  * Test if a mapping is valid with either dma_buf_map_is_set() or
  * dma_buf_map_is_null().
  *
@@ -118,6 +124,20 @@  static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
 	map->is_iomem = false;
 }
 
+/**
+ * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
+ * @map:		The dma-buf mapping structure
+ * @vaddr_iomem:	An I/O-memory address
+ *
+ * Sets the address and the I/O-memory flag.
+ */
+static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
+					       void __iomem *vaddr_iomem)
+{
+	map->vaddr_iomem = vaddr_iomem;
+	map->is_iomem = true;
+}
+
 /**
  * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
  * @lhs:	The dma-buf mapping structure