[PATCH] nouveau: use ttm populate mapping functions. (v2)

[Ben Skeggs]

On Wed, 29 Jul 2020 at 02:08, Ruhl, Michael J <michael.j.ruhl at intel.com> wrote:
>
> >-----Original Message-----
> >From: dri-devel <dri-devel-bounces at lists.freedesktop.org> On Behalf Of
> >Dave Airlie
> >Sent: Monday, July 27, 2020 11:26 PM
> >To: dri-devel at lists.freedesktop.org
> >Cc: bskeggs at redhat.com
> >Subject: [PATCH] nouveau: use ttm populate mapping functions. (v2)
> >
> >From: Dave Airlie <airlied at redhat.com>
> >
> >Instead of rolling driver copies of them.
> >
> >v2: cleanup return handling (Ben)
> >Signed-off-by: Dave Airlie <airlied at redhat.com>
> >---
> > drivers/gpu/drm/nouveau/nouveau_bo.c | 38 ++--------------------------
> > 1 file changed, 2 insertions(+), 36 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c
> >b/drivers/gpu/drm/nouveau/nouveau_bo.c
> >index 7806278dce57..6ef5085c9a91 100644
> >--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
> >+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
> >@@ -1231,8 +1231,6 @@ nouveau_ttm_tt_populate(struct ttm_tt *ttm,
> >struct ttm_operation_ctx *ctx)
> >       struct ttm_dma_tt *ttm_dma = (void *)ttm;
> >       struct nouveau_drm *drm;
> >       struct device *dev;
> >-      unsigned i;
> >-      int r;
> >       bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
> >
> >       if (ttm->state != tt_unpopulated)
> >@@ -1260,31 +1258,7 @@ nouveau_ttm_tt_populate(struct ttm_tt *ttm,
> >struct ttm_operation_ctx *ctx)
> >               return ttm_dma_populate((void *)ttm, dev, ctx);
> >       }
> > #endif
> >-
> >-      r = ttm_pool_populate(ttm, ctx);
> >-      if (r) {
> >-              return r;
> >-      }
> >-
> >-      for (i = 0; i < ttm->num_pages; i++) {
> >-              dma_addr_t addr;
> >-
> >-              addr = dma_map_page(dev, ttm->pages[i], 0, PAGE_SIZE,
> >-                                  DMA_BIDIRECTIONAL);
> >-
> >-              if (dma_mapping_error(dev, addr)) {
> >-                      while (i--) {
> >-                              dma_unmap_page(dev, ttm_dma-
> >>dma_address[i],
> >-                                             PAGE_SIZE,
> >DMA_BIDIRECTIONAL);
> >-                              ttm_dma->dma_address[i] = 0;
> >-                      }
> >-                      ttm_pool_unpopulate(ttm);
> >-                      return -EFAULT;
> >-              }
> >-
> >-              ttm_dma->dma_address[i] = addr;
> >-      }
> >-      return 0;
> >+      return ttm_populate_and_map_pages(dev, ttm_dma, ctx);
>
> This is not a completely straight code replacement.
>
> ttm_populate_and_map_pages() also has code to deal with pages that are
> contiguous (consolidates them).
>
> Is it possible that the nouveau HW can't handle a contiguous buffer larger
> than PAG_SIZE?
I think it's fine.  The function appears to consolidate the pages for
the dma_map_page() call, but otherwise leave dma_address[] in
PAGE_SIZE chunks, I don't believe anything else in the driver will
care.

Ben.

>
> Thanks,
>
> Mike
>
> > }
> >
> > static void
> >@@ -1293,7 +1267,6 @@ nouveau_ttm_tt_unpopulate(struct ttm_tt *ttm)
> >       struct ttm_dma_tt *ttm_dma = (void *)ttm;
> >       struct nouveau_drm *drm;
> >       struct device *dev;
> >-      unsigned i;
> >       bool slave = !!(ttm->page_flags & TTM_PAGE_FLAG_SG);
> >
> >       if (slave)
> >@@ -1316,14 +1289,7 @@ nouveau_ttm_tt_unpopulate(struct ttm_tt *ttm)
> >       }
> > #endif
> >
> >-      for (i = 0; i < ttm->num_pages; i++) {
> >-              if (ttm_dma->dma_address[i]) {
> >-                      dma_unmap_page(dev, ttm_dma->dma_address[i],
> >PAGE_SIZE,
> >-                                     DMA_BIDIRECTIONAL);
> >-              }
> >-      }
> >-
> >-      ttm_pool_unpopulate(ttm);
> >+      ttm_unmap_and_unpopulate_pages(dev, ttm_dma);
> > }
> >
> > void
> >--
> >2.26.2
> >
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