Hi Am 07.10.20 um 15:10 schrieb Daniel Vetter: > On Wed, Oct 7, 2020 at 2:57 PM Thomas Zimmermann <tzimmerm...@suse.de> wrote: >> >> 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.koe...@amd.com> 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. > > ttm_bo_vmap would simply wrap what you currently open-code as > ttm_bo_kmap + ttm_kmap_obj_to_dma_buf_map. Removing ttm_kmap_obj would > be a much later step. Why do you think adding ttm_bo_vmap is not > possible?
The calls to ttm_bo_kmap/_kunmap() require an instance of struct
ttm_bo_kmap_obj that is stored in each driver's private bo structure
(e.g., struct drm_gem_vram_object, struct radeon_bo, etc). When I made
patch 3, I flirted with the idea of unifying the driver's _vmap code in
a shared helper, but I couldn't find a simple way of doing it. That's
why it's open-coded in the first place.
Best regards
Thomas
> -Daniel
>
>
>> 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 <tzimmerm...@suse.de>
>>>>>>>>>>>> ---
>>>>>>>>>>>> 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
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>>>>>>>>>> _______________________________________________
>>>>>>>>>> amd-gfx mailing list
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>>>>>>>>> _______________________________________________
>>>>>>>>> dri-devel mailing list
>>>>>>>>> dri-de...@lists.freedesktop.org
>>>>>>>>> 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@lists.freedesktop.org
>>>>>>>> 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
>>
>
>
--
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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