drm/i915: extend i915_vma_pin_iomap()

In the future display might try call this with a normal smem object,
which doesn't require PIN_MAPPABLE underneath in order to CPU map the
pages (unlike stolen).  Extend i915_vma_pin_iomap() to directly use
i915_gem_object_pin_map() for such cases.

This change was suggested by Chris P Wilson, that we pin
the smem with i915_gem_object_pin_map_unlocked().

v2 (jheikkil): Change i915_gem_object_pin_map_unlocked to
               i915_gem_object_pin_map

Signed-off-by: CQ Tang <cq.tang@intel.com>
Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Cc: Chris Wilson <chris.p.wilson@intel.com>
Cc: Jari Tahvanainen <jari.tahvanainen@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
[mauld: tweak commit message, plus minor checkpatch fix]
Link: https://patchwork.freedesktop.org/patch/msgid/20220610121205.29645-2-juhapekka.heikkila@gmail.com

diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index d333c44..5d5828b 100644 (file)
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -551,13 +551,6 @@ void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
        if (WARN_ON_ONCE(vma->obj->flags & I915_BO_ALLOC_GPU_ONLY))
                return IOMEM_ERR_PTR(-EINVAL);
 
-       if (!i915_gem_object_is_lmem(vma->obj)) {
-               if (GEM_WARN_ON(!i915_vma_is_map_and_fenceable(vma))) {
-                       err = -ENODEV;
-                       goto err;
-               }
-       }
-
        GEM_BUG_ON(!i915_vma_is_ggtt(vma));
        GEM_BUG_ON(!i915_vma_is_bound(vma, I915_VMA_GLOBAL_BIND));
        GEM_BUG_ON(i915_vma_verify_bind_complete(vma));
@@ -570,20 +563,33 @@ void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
                 * of pages, that way we can also drop the
                 * I915_BO_ALLOC_CONTIGUOUS when allocating the object.
                 */
-               if (i915_gem_object_is_lmem(vma->obj))
+               if (i915_gem_object_is_lmem(vma->obj)) {
                        ptr = i915_gem_object_lmem_io_map(vma->obj, 0,
                                                          vma->obj->base.size);
-               else
+               } else if (i915_vma_is_map_and_fenceable(vma)) {
                        ptr = io_mapping_map_wc(&i915_vm_to_ggtt(vma->vm)->iomap,
                                                vma->node.start,
                                                vma->node.size);
+               } else {
+                       ptr = (void __iomem *)
+                               i915_gem_object_pin_map(vma->obj, I915_MAP_WC);
+                       if (IS_ERR(ptr)) {
+                               err = PTR_ERR(ptr);
+                               goto err;
+                       }
+                       ptr = page_pack_bits(ptr, 1);
+               }
+
                if (ptr == NULL) {
                        err = -ENOMEM;
                        goto err;
                }
 
                if (unlikely(cmpxchg(&vma->iomap, NULL, ptr))) {
-                       io_mapping_unmap(ptr);
+                       if (page_unmask_bits(ptr))
+                               __i915_gem_object_release_map(vma->obj);
+                       else
+                               io_mapping_unmap(ptr);
                        ptr = vma->iomap;
                }
        }
@@ -597,7 +603,7 @@ void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
        i915_vma_set_ggtt_write(vma);
 
        /* NB Access through the GTT requires the device to be awake. */
-       return ptr;
+       return page_mask_bits(ptr);
 
 err_unpin:
        __i915_vma_unpin(vma);
@@ -615,6 +621,8 @@ void i915_vma_unpin_iomap(struct i915_vma *vma)
 {
        GEM_BUG_ON(vma->iomap == NULL);
 
+       /* XXX We keep the mapping until __i915_vma_unbind()/evict() */
+
        i915_vma_flush_writes(vma);
 
        i915_vma_unpin_fence(vma);
@@ -1763,7 +1771,10 @@ static void __i915_vma_iounmap(struct i915_vma *vma)
        if (vma->iomap == NULL)
                return;
 
-       io_mapping_unmap(vma->iomap);
+       if (page_unmask_bits(vma->iomap))
+               __i915_gem_object_release_map(vma->obj);
+       else
+               io_mapping_unmap(vma->iomap);
        vma->iomap = NULL;
 }