Nouveau - Oct 2020 - [PATCH v4 05/10] drm/ttm: Add vmap/vunmap to TTM and TTM GEM helpers

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 at 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

On Thu, Oct 15, 2020 at 04:08:13PM +0200, Christian K?nig
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 at ffwll.ch>

Thanks a lot for doing all this.
-Daniel
> 
> > 
> > Signed-off-by: Thomas Zimmermann <tzimmermann at 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
> 
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Hi

On Thu, 15 Oct 2020 18:49:09 +0200 Daniel Vetter <daniel at ffwll.ch>
wrote:
> On Thu, Oct 15, 2020 at 04:08:13PM +0200, Christian K?nig 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.

Best regards
Thomas
> 
> I'll let Christian with the details, but at a high level this is
> definitely
> 
> Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> 
> Thanks a lot for doing all this.
> -Daniel
> 
> > 
> > > 
> > > Signed-off-by: Thomas Zimmermann <tzimmermann at 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
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 N?rnberg, Germany
(HRB 36809, AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

Hi

On Thu, 15 Oct 2020 16:08:13 +0200 Christian K?nig <christian.koenig at
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 at 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 at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel


-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 N?rnberg, Germany
(HRB 36809, AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

Hi Christian

On 15.10.20 16:08, Christian K?nig 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 at 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 at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 N?rnberg, Germany
(HRB 36809, AG N?rnberg)
Gesch?ftsf?hrer: Felix Imend?rffer

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
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