[PATCH 1/2] drm/nouveau/bar: add noncached ioremap property

[Alexandre Courbot]

Some BARs (like GK20A's) do not support being ioremapped write-combined.
Add a boolean property to the BAR structure and handle that case in the
Nouveau BO implementation.

Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
---
 drivers/gpu/drm/nouveau/core/include/subdev/bar.h |  3 +++
 drivers/gpu/drm/nouveau/nouveau_bo.c              | 17 ++++++++++++-----
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/bar.h 
b/drivers/gpu/drm/nouveau/core/include/subdev/bar.h
index 9faa98e67ad8..9002cbb6432b 100644
--- a/drivers/gpu/drm/nouveau/core/include/subdev/bar.h
+++ b/drivers/gpu/drm/nouveau/core/include/subdev/bar.h
@@ -20,6 +20,9 @@ struct nouveau_bar {
                    u32 flags, struct nouveau_vma *);
        void (*unmap)(struct nouveau_bar *, struct nouveau_vma *);
        void (*flush)(struct nouveau_bar *);
+
+       /* whether the BAR supports to be ioremapped WC or should be uncached */
+       bool iomap_uncached;
 };

 static inline struct nouveau_bar *
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c 
b/drivers/gpu/drm/nouveau/nouveau_bo.c
index b6dc85c614be..4db886f9f793 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -500,18 +500,25 @@ nouveau_bo_init_mem_type(struct ttm_bo_device *bdev, 
uint32_t type,
                man->default_caching = TTM_PL_FLAG_CACHED;
                break;
        case TTM_PL_VRAM:
+               man->flags = TTM_MEMTYPE_FLAG_FIXED |
+                            TTM_MEMTYPE_FLAG_MAPPABLE;
+               man->available_caching = TTM_PL_FLAG_UNCACHED |
+                                        TTM_PL_FLAG_WC;
+               man->default_caching = TTM_PL_FLAG_WC;
+
                if (nv_device(drm->device)->card_type >= NV_50) {
+                       /* Some BARs do not support being ioremapped WC */
+                       if (nouveau_bar(drm->device)->iomap_uncached) {
+                               man->available_caching = TTM_PL_FLAG_UNCACHED;
+                               man->default_caching = TTM_PL_FLAG_UNCACHED;
+                       }
+
                        man->func = &nouveau_vram_manager;
                        man->io_reserve_fastpath = false;
                        man->use_io_reserve_lru = true;
                } else {
                        man->func = &ttm_bo_manager_func;
                }
-               man->flags = TTM_MEMTYPE_FLAG_FIXED |
-                            TTM_MEMTYPE_FLAG_MAPPABLE;
-               man->available_caching = TTM_PL_FLAG_UNCACHED |
-                                        TTM_PL_FLAG_WC;
-               man->default_caching = TTM_PL_FLAG_WC;
                break;
        case TTM_PL_TT:
                if (nv_device(drm->device)->card_type >= NV_50)
-- 
2.0.0