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Hi Am 02.10.20 um 11:58 schrieb Daniel Vetter: > On Wed, Sep 30, 2020 at 02:51:46PM +0200, Daniel Vetter wrote: >> On Wed, Sep 30, 2020 at 2:34 PM Christian König >> <christian.koenig@xxxxxxx> wrote: >>> >>> Am 30.09.20 um 11:47 schrieb Daniel Vetter: >>>> On Wed, Sep 30, 2020 at 10:34:31AM +0200, Christian König wrote: >>>>> Am 30.09.20 um 10:19 schrieb Thomas Zimmermann: >>>>>> Hi >>>>>> >>>>>> Am 30.09.20 um 10:05 schrieb Christian König: >>>>>>> Am 29.09.20 um 19:49 schrieb Thomas Zimmermann: >>>>>>>> Hi Christian >>>>>>>> >>>>>>>> Am 29.09.20 um 17:35 schrieb Christian König: >>>>>>>>> Am 29.09.20 um 17:14 schrieb Thomas Zimmermann: >>>>>>>>>> The new helper ttm_kmap_obj_to_dma_buf() extracts address and >>>>>>>>>> location >>>>>>>>>> from and instance of TTM's kmap_obj and initializes struct >>>>>>>>>> dma_buf_map >>>>>>>>>> with these values. Helpful for TTM-based drivers. >>>>>>>>> We could completely drop that if we use the same structure inside TTM >>>>>>>>> as >>>>>>>>> well. >>>>>>>>> >>>>>>>>> Additional to that which driver is going to use this? >>>>>>>> As Daniel mentioned, it's in patch 3. The TTM-based drivers will >>>>>>>> retrieve the pointer via this function. >>>>>>>> >>>>>>>> I do want to see all that being more tightly integrated into TTM, but >>>>>>>> not in this series. This one is about fixing the bochs-on-sparc64 >>>>>>>> problem for good. Patch 7 adds an update to TTM to the DRM TODO list. >>>>>>> I should have asked which driver you try to fix here :) >>>>>>> >>>>>>> In this case just keep the function inside bochs and only fix it there. >>>>>>> >>>>>>> All other drivers can be fixed when we generally pump this through TTM. >>>>>> Did you take a look at patch 3? This function will be used by VRAM >>>>>> helpers, nouveau, radeon, amdgpu and qxl. If we don't put it here, we >>>>>> have to duplicate the functionality in each if these drivers. Bochs >>>>>> itself uses VRAM helpers and doesn't touch the function directly. >>>>> Ah, ok can we have that then only in the VRAM helpers? >>>>> >>>>> Alternative you could go ahead and use dma_buf_map in ttm_bo_kmap_obj >>>>> directly and drop the hack with the TTM_BO_MAP_IOMEM_MASK. >>>>> >>>>> What I want to avoid is to have another conversion function in TTM because >>>>> what happens here is that we already convert from ttm_bus_placement to >>>>> ttm_bo_kmap_obj and then to dma_buf_map. >>>> Hm I'm not really seeing how that helps with a gradual conversion of >>>> everything over to dma_buf_map and assorted helpers for access? There's >>>> too many places in ttm drivers where is_iomem and related stuff is used to >>>> be able to convert it all in one go. An intermediate state with a bunch of >>>> conversions seems fairly unavoidable to me. >>> >>> Fair enough. I would just have started bottom up and not top down. >>> >>> Anyway feel free to go ahead with this approach as long as we can remove >>> the new function again when we clean that stuff up for good. >> >> Yeah I guess bottom up would make more sense as a refactoring. But the >> main motivation to land this here is to fix the __mmio vs normal >> memory confusion in the fbdev emulation helpers for sparc (and >> anything else that needs this). Hence the top down approach for >> rolling this out. > > Ok I started reviewing this a bit more in-depth, and I think this is a bit > too much of a de-tour. > > Looking through all the callers of ttm_bo_kmap almost everyone maps the > entire object. Only vmwgfx uses to map less than that. Also, everyone just > immediately follows up with converting that full object map into a > pointer. > > So I think what we really want here is: > - new function > > int ttm_bo_vmap(struct ttm_buffer_object *bo, struct dma_buf_map *map); > > _vmap name since that's consistent with both dma_buf functions and > what's usually used to implement this. Outside of the ttm world kmap > usually just means single-page mappings using kmap() or it's iomem > sibling io_mapping_map* so rather confusing name for a function which > usually is just used to set up a vmap of the entire buffer. > > - a helper which can be used for the drm_gem_object_funcs vmap/vunmap > functions for all ttm drivers. We should be able to make this fully > generic because a) we now have dma_buf_map and b) drm_gem_object is > embedded in the ttm_bo, so we can upcast for everyone who's both a ttm > and gem driver. > > This is maybe a good follow-up, since it should allow us to ditch quite > a bit of the vram helper code for this more generic stuff. I also might > have missed some special-cases here, but from a quick look everything > just pins the buffer to the current location and that's it. > > Also this obviously requires Christian's generic ttm_bo_pin rework > first. > > - roll the above out to drivers. > > Christian/Thomas, thoughts on this? I agree on the goals, but what is the immediate objective here? Adding ttm_bo_vmap() does not work out easily, as struct ttm_bo_kmap_obj is a central part of the internals of TTM. struct ttm_bo_kmap_obj has more internal state that struct dma_buf_map, so they are not easily convertible either. What you propose seems to require a reimplementation of the existing ttm_bo_kmap() code. That is it's own patch series. I'd rather go with some variant of the existing patch and add ttm_bo_vmap() in a follow-up. Best regards Thomas > > I think for the immediate need of rolling this out for vram helpers and > fbdev code we should be able to do this, but just postpone the driver wide > roll-out for now. > > Cheers, Daniel > >> -Daniel >> >>> >>> Christian. >>> >>>> -Daniel >>>> >>>>> Thanks, >>>>> Christian. >>>>> >>>>>> Best regards >>>>>> Thomas >>>>>> >>>>>>> Regards, >>>>>>> Christian. >>>>>>> >>>>>>>> Best regards >>>>>>>> Thomas >>>>>>>> >>>>>>>>> Regards, >>>>>>>>> Christian. >>>>>>>>> >>>>>>>>>> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> >>>>>>>>>> --- >>>>>>>>>> include/drm/ttm/ttm_bo_api.h | 24 ++++++++++++++++++++++++ >>>>>>>>>> include/linux/dma-buf-map.h | 20 ++++++++++++++++++++ >>>>>>>>>> 2 files changed, 44 insertions(+) >>>>>>>>>> >>>>>>>>>> diff --git a/include/drm/ttm/ttm_bo_api.h >>>>>>>>>> b/include/drm/ttm/ttm_bo_api.h >>>>>>>>>> index c96a25d571c8..62d89f05a801 100644 >>>>>>>>>> --- a/include/drm/ttm/ttm_bo_api.h >>>>>>>>>> +++ b/include/drm/ttm/ttm_bo_api.h >>>>>>>>>> @@ -34,6 +34,7 @@ >>>>>>>>>> #include <drm/drm_gem.h> >>>>>>>>>> #include <drm/drm_hashtab.h> >>>>>>>>>> #include <drm/drm_vma_manager.h> >>>>>>>>>> +#include <linux/dma-buf-map.h> >>>>>>>>>> #include <linux/kref.h> >>>>>>>>>> #include <linux/list.h> >>>>>>>>>> #include <linux/wait.h> >>>>>>>>>> @@ -486,6 +487,29 @@ static inline void *ttm_kmap_obj_virtual(struct >>>>>>>>>> ttm_bo_kmap_obj *map, >>>>>>>>>> return map->virtual; >>>>>>>>>> } >>>>>>>>>> +/** >>>>>>>>>> + * ttm_kmap_obj_to_dma_buf_map >>>>>>>>>> + * >>>>>>>>>> + * @kmap: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap. >>>>>>>>>> + * @map: Returns the mapping as struct dma_buf_map >>>>>>>>>> + * >>>>>>>>>> + * Converts struct ttm_bo_kmap_obj to struct dma_buf_map. If the >>>>>>>>>> memory >>>>>>>>>> + * is not mapped, the returned mapping is initialized to NULL. >>>>>>>>>> + */ >>>>>>>>>> +static inline void ttm_kmap_obj_to_dma_buf_map(struct >>>>>>>>>> ttm_bo_kmap_obj >>>>>>>>>> *kmap, >>>>>>>>>> + struct dma_buf_map *map) >>>>>>>>>> +{ >>>>>>>>>> + bool is_iomem; >>>>>>>>>> + void *vaddr = ttm_kmap_obj_virtual(kmap, &is_iomem); >>>>>>>>>> + >>>>>>>>>> + if (!vaddr) >>>>>>>>>> + dma_buf_map_clear(map); >>>>>>>>>> + else if (is_iomem) >>>>>>>>>> + dma_buf_map_set_vaddr_iomem(map, (void __force __iomem >>>>>>>>>> *)vaddr); >>>>>>>>>> + else >>>>>>>>>> + dma_buf_map_set_vaddr(map, vaddr); >>>>>>>>>> +} >>>>>>>>>> + >>>>>>>>>> /** >>>>>>>>>> * ttm_bo_kmap >>>>>>>>>> * >>>>>>>>>> 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@xxxxxxxxxxxxxxxxxxxxx >>>>>>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fdri-devel&data=02%7C01%7Cchristian.koenig%40amd.com%7C472c3d655a61411deb6708d86525d1b8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637370560438965013&sdata=HdHOA%2F1VcIX%2F7YtfYTiAqYEvw7Ag%2FS%2BxS5VwJKOv5y0%3D&reserved=0 >>>>>>>> _______________________________________________ >>>>>>>> amd-gfx mailing list >>>>>>>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx >>>>>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=02%7C01%7Cchristian.koenig%40amd.com%7C472c3d655a61411deb6708d86525d1b8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637370560438965013&sdata=H%2B5HKCsTrksRV2EyEiFGSTyS79jsWCmJimSMoJYusx8%3D&reserved=0 >>>>>>> _______________________________________________ >>>>>>> dri-devel mailing list >>>>>>> dri-devel@xxxxxxxxxxxxxxxxxxxxx >>>>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Fdri-devel&data=02%7C01%7Cchristian.koenig%40amd.com%7C472c3d655a61411deb6708d86525d1b8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637370560438965013&sdata=HdHOA%2F1VcIX%2F7YtfYTiAqYEvw7Ag%2FS%2BxS5VwJKOv5y0%3D&reserved=0 >>>>>>> >>>>>> _______________________________________________ >>>>>> amd-gfx mailing list >>>>>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx >>>>>> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=02%7C01%7Cchristian.koenig%40amd.com%7C472c3d655a61411deb6708d86525d1b8%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637370560438965013&sdata=H%2B5HKCsTrksRV2EyEiFGSTyS79jsWCmJimSMoJYusx8%3D&reserved=0 >>> >> >> >> -- >> Daniel Vetter >> Software Engineer, Intel Corporation >> http://blog.ffwll.ch > -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Felix Imendörffer

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Re: [PATCH v3 2/7] drm/ttm: Add ttm_kmap_obj_to_dma_buf_map() for type conversion