Re: [PATCH] drm/ttm: ioremap buffer according to TTM mem caching setting

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

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Hi Oak,

as far as I know some architectures like PowerPC/ARM/MIPS need that. And 
we at least officially support PowerPC and ARM and MIPS is best effort 
and shouldn't break if possible.

Thomas just recently had a whole bunch of DMA-buf patches to also fix 
that up for DMA-bufs vmap as well, previously we have just been casting 
away the __iomem and hoped that it always works.

Regards,
Christian.

Am 03.03.21 um 21:59 schrieb Zeng, Oak:
>
> [AMD Official Use Only - Internal Distribution Only]
>
>
> Hi Christian,
>
> Can you explain why __iomem annotation is mandatory for amdgpu driver? 
> If this is the case, we can’t switch to memremap. The only fix seems 
> to me is add a #ifdef __x86_64__ to the ioremap_cache codes.
>
> Regards,
>
> Oak
>
> *From:* Christian König <ckoenig.leichtzumerken@gmail.com>
> *Sent:* Wednesday, March 3, 2021 5:46 AM
> *To:* Zeng, Oak <Oak.Zeng@amd.com>; amd-gfx@lists.freedesktop.org; 
> dri-devel@lists.freedesktop.org; Daniel Vetter <daniel@ffwll.ch>; Dave 
> Airlie <airlied@redhat.com>; Thomas Hellström (Intel) 
> <thomas_os@shipmail.org>; dan.j.williams@intel.com
> *Cc:* kbuild-all@lists.01.org; Kuehling, Felix 
> <Felix.Kuehling@amd.com>; Kasiviswanathan, Harish 
> <Harish.Kasiviswanathan@amd.com>; Deucher, Alexander 
> <Alexander.Deucher@amd.com>; Huang, JinHuiEric 
> <JinHuiEric.Huang@amd.com>; Koenig, Christian <Christian.Koenig@amd.com>
> *Subject:* Re: [PATCH] drm/ttm: ioremap buffer according to TTM mem 
> caching setting
>
> Hi Oak,
>
>
>     config: parisc-randconfig-r012-20210302 (attached as .config)
>
>
> It's not the Intel driver build which fails here, but the build bot is 
> just hosted by Intel.
>
> The problem is that the parisc architecture doesn't defines the 
> ioremap_cache() function.
>
> I've looked at using memremap() instead of ioremap_cache(). The 
> problem is that we do support architectures with the TTM as well as 
> amndgpu code where the __iomem annotation is mandatory and correct.
>
> Regards,
> Christian.
>
> Am 02.03.21 um 23:45 schrieb Zeng, Oak:
>
>     [AMD Official Use Only - Internal Distribution Only]
>
>     Hi Daniel, Thomas, Dan,
>
>     Does below message mean the calling ioremap_cache failed intel’s
>     driver build? I can see both ioremap_cache and ioremap_wc are
>     defined in arch/x86/mm/ioremap.c – why ioremap_wc doesn’t break
>     intel driver’s build?
>
>     Are we supposed to use memremap (offset, size, MEMREMAP_WB) to
>     replace ioremap_cache? When I read here
>     https://lwn.net/Articles/653585/
>     <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flwn.net%2FArticles%2F653585%2F&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624296472%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ljCFrIfrYbb%2FXmKKS2TJ7dSQ7oCRNWoUhWS4gEBv%2FW4%3D&reserved=0>
>     I felt that ioremap_cache returns an address annotated with _iomem
>     while memremap returns an address without __iomem annotation. In
>     our use case, GPU memory is treated as UEFI SPM (specific purpose
>     memory). I am not very sure whether memremap (thus no __iomem
>     annotation) is the right thing to do. What I am sure is, we have
>     tested ioremap_cache and it works fine on AMD system.
>
>     I will send out a test patch replacing ioremap_cache with
>     ioremap_wc, to trigger Intel build robot to see whether it fails
>     Intel build. I suppose it will not fail Intel build.
>
>     Regards,
>
>     Oak
>
>     *From:* Christian König <ckoenig.leichtzumerken@gmail.com>
>     <mailto:ckoenig.leichtzumerken@gmail.com>
>     *Sent:* Tuesday, March 2, 2021 6:31 AM
>     *To:* amd-gfx@lists.freedesktop.org
>     <mailto:amd-gfx@lists.freedesktop.org>;
>     dri-devel@lists.freedesktop.org
>     <mailto:dri-devel@lists.freedesktop.org>; Daniel Vetter
>     <daniel@ffwll.ch> <mailto:daniel@ffwll.ch>; Dave Airlie
>     <airlied@redhat.com> <mailto:airlied@redhat.com>; Thomas Hellström
>     (Intel) <thomas_os@shipmail.org> <mailto:thomas_os@shipmail.org>
>     *Cc:* Zeng, Oak <Oak.Zeng@amd.com> <mailto:Oak.Zeng@amd.com>;
>     kbuild-all@lists.01.org <mailto:kbuild-all@lists.01.org>;
>     Kuehling, Felix <Felix.Kuehling@amd.com>
>     <mailto:Felix.Kuehling@amd.com>; Kasiviswanathan, Harish
>     <Harish.Kasiviswanathan@amd.com>
>     <mailto:Harish.Kasiviswanathan@amd.com>; Deucher, Alexander
>     <Alexander.Deucher@amd.com> <mailto:Alexander.Deucher@amd.com>;
>     Huang, JinHuiEric <JinHuiEric.Huang@amd.com>
>     <mailto:JinHuiEric.Huang@amd.com>; Koenig, Christian
>     <Christian.Koenig@amd.com> <mailto:Christian.Koenig@amd.com>
>     *Subject:* Re: [PATCH] drm/ttm: ioremap buffer according to TTM
>     mem caching setting
>
>     Hi guys,
>
>     adding the usual suspects direct. Does anybody of hand know how to
>     check if an architecture supports ioremap_cache()?
>
>     For now we only need this on X86, but I would feel better if we
>     don't use an #ifdef here.
>
>     Regards,
>     Christian.
>
>     Am 02.03.21 um 05:12 schrieb kernel test robot:
>
>         Hi Oak,
>
>           
>
>         Thank you for the patch! Yet something to improve:
>
>           
>
>         [auto build test ERROR on drm-intel/for-linux-next]
>
>         [also build test ERROR on drm-tip/drm-tip linus/master v5.12-rc1 next-20210302]
>
>         [cannot apply to tegra-drm/drm/tegra/for-next drm-exynos/exynos-drm-next drm/drm-next]
>
>         [If your patch is applied to the wrong git tree, kindly drop us a note.
>
>         And when submitting patch, we suggest to use '--base' as documented in
>
>         https://git-scm.com/docs/git-format-patch  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit-scm.com%2Fdocs%2Fgit-format-patch&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624306464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=3f5ib%2FlZ6DXXF%2Bk1rXPKGu1IkOhXHdkUmX3obtuIRtA%3D&reserved=0>]
>
>           
>
>         url:https://github.com/0day-ci/linux/commits/Oak-Zeng/drm-ttm-ioremap-buffer-according-to-TTM-mem-caching-setting/20210302-064500  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux%2Fcommits%2FOak-Zeng%2Fdrm-ttm-ioremap-buffer-according-to-TTM-mem-caching-setting%2F20210302-064500&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624306464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Y9h9ZHM7d2Sqo3XQWr%2Frpb2DAk9SkHFIm5nD4ABFNbE%3D&reserved=0>
>
>         base:   git://anongit.freedesktop.org/drm-intel for-linux-next
>
>         config: parisc-randconfig-r012-20210302 (attached as .config)
>
>         compiler: hppa-linux-gcc (GCC) 9.3.0
>
>         reproduce (this is a W=1 build):
>
>                  wgethttps://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fraw.githubusercontent.com%2Fintel%2Flkp-tests%2Fmaster%2Fsbin%2Fmake.cross&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624316464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=wGo3Nwk4mWZjb2W3E7qKf3FtKzLOxCVmQu1zd2rmzRU%3D&reserved=0>  -O ~/bin/make.cross
>
>                  chmod +x ~/bin/make.cross
>
>                  #https://github.com/0day-ci/linux/commit/225bb3711439ec559dd72ae5af8e62d34ea60a64  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux%2Fcommit%2F225bb3711439ec559dd72ae5af8e62d34ea60a64&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624316464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=kOz18UAawmA4SZ6IrCGRt4HISfsmmjfGN2TUgAtm0Ak%3D&reserved=0>
>
>                  git remote add linux-reviewhttps://github.com/0day-ci/linux  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2F0day-ci%2Flinux&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624326458%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=QnKs47gjzAz%2Fjv%2FAO6H%2BwYNQF6mdk1D8dCNveW0YHuM%3D&reserved=0>
>
>                  git fetch --no-tags linux-review Oak-Zeng/drm-ttm-ioremap-buffer-according-to-TTM-mem-caching-setting/20210302-064500
>
>                  git checkout 225bb3711439ec559dd72ae5af8e62d34ea60a64
>
>                  # save the attached .config to linux build tree
>
>                  COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=parisc
>
>           
>
>         If you fix the issue, kindly add following tag as appropriate
>
>         Reported-by: kernel test robot<lkp@intel.com>  <mailto:lkp@intel.com>
>
>           
>
>         All errors (new ones prefixed by >>):
>
>           
>
>             drivers/gpu/drm/ttm/ttm_bo_util.c: In function 'ttm_resource_ioremap':
>
>                 drivers/gpu/drm/ttm/ttm_bo_util.c:95:11: error: implicit declaration of function 'ioremap_cache'; did you mean 'ioremap_uc'? [-Werror=implicit-function-declaration]
>
>                95 |    addr = ioremap_cache(mem->bus.offset, bus_size);
>
>                   |           ^~~~~~~~~~~~~
>
>                   |           ioremap_uc
>
>             drivers/gpu/drm/ttm/ttm_bo_util.c:95:9: warning: assignment to 'void *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
>
>                95 |    addr = ioremap_cache(mem->bus.offset, bus_size);
>
>                   |         ^
>
>             drivers/gpu/drm/ttm/ttm_bo_util.c: In function 'ttm_bo_ioremap':
>
>             drivers/gpu/drm/ttm/ttm_bo_util.c:379:17: warning: assignment to 'void *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
>
>               379 |    map->virtual = ioremap_cache(bo->mem.bus.offset + offset,
>
>                   |                 ^
>
>             drivers/gpu/drm/ttm/ttm_bo_util.c: In function 'ttm_bo_vmap':
>
>             drivers/gpu/drm/ttm/ttm_bo_util.c:500:16: warning: assignment to 'void *' from 'int' makes pointer from integer without a cast [-Wint-conversion]
>
>               500 |    vaddr_iomem = ioremap_cache(mem->bus.offset,
>
>                   |                ^
>
>             cc1: some warnings being treated as errors
>
>           
>
>           
>
>         vim +95 drivers/gpu/drm/ttm/ttm_bo_util.c
>
>           
>
>              74
>
>              75  static int ttm_resource_ioremap(struct ttm_bo_device *bdev,
>
>              76                                struct ttm_resource *mem,
>
>              77                                void **virtual)
>
>              78  {
>
>              79          int ret;
>
>              80          void *addr;
>
>              81
>
>              82          *virtual = NULL;
>
>              83          ret = ttm_mem_io_reserve(bdev, mem);
>
>              84          if (ret || !mem->bus.is_iomem)
>
>              85                  return ret;
>
>              86
>
>              87          if (mem->bus.addr) {
>
>              88                  addr = mem->bus.addr;
>
>              89          } else {
>
>              90                  size_t bus_size = (size_t)mem->num_pages << PAGE_SHIFT;
>
>              91
>
>              92                  if (mem->bus.caching == ttm_write_combined)
>
>              93                         addr = ioremap_wc(mem->bus.offset, bus_size);
>
>              94                  else if (mem->bus.caching == ttm_cached)
>
>            > 95                         addr = ioremap_cache(mem->bus.offset, bus_size);
>
>              96                  else
>
>              97                         addr = ioremap(mem->bus.offset, bus_size);
>
>              98                  if (!addr) {
>
>              99                         ttm_mem_io_free(bdev, mem);
>
>             100                         return -ENOMEM;
>
>             101                  }
>
>             102          }
>
>             103          *virtual = addr;
>
>             104          return 0;
>
>             105  }
>
>             106
>
>           
>
>         ---
>
>         0-DAY CI Kernel Test Service, Intel Corporation
>
>         https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.01.org%2Fhyperkitty%2Flist%2Fkbuild-all%40lists.01.org&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624326458%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=MY6tEGVY0X4VyS750dYmsfVoR71Zp78YdxuqqRljnsI%3D&reserved=0>
>
>
>
>
>         _______________________________________________
>
>         amd-gfx mailing list
>
>         amd-gfx@lists.freedesktop.org  <mailto:amd-gfx@lists.freedesktop.org>
>
>         https://lists.freedesktop.org/mailman/listinfo/amd-gfx  <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&data=04%7C01%7COak.Zeng%40amd.com%7Cc047ecb316df47cde7ed08d8de3188d4%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637503651624336455%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=Or3tWmS5M6mXOaFP4FHsEbg0rqoizNGpTl6JEkD6fac%3D&reserved=0>
>


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