Hi Christoph,
Le jeu. 11 mars 2021 à 12:26, Christoph Hellwig <hch@xxxxxxxxxxxxx> a
écrit :
+int drm_gem_cma_mmap_noncoherent(struct drm_gem_object *obj,
+ struct vm_area_struct *vma)
+{
+ struct drm_gem_cma_object *cma_obj;
+ unsigned long pfn;
+ int ret;
+
+ /*
+ * Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and
set the
+ * vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want
to map
+ * the whole buffer.
+ */
+ vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node);
+ vma->vm_flags &= ~VM_PFNMAP;
+ vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+
+ cma_obj = to_drm_gem_cma_obj(obj);
+
+ pfn = PHYS_PFN(dma_to_phys(cma_obj->base.dev->dev,
cma_obj->paddr));
+
+ ret = remap_pfn_range(vma, vma->vm_start, pfn,
+ vma->vm_end - vma->vm_start,
+ vma->vm_page_prot);
dma_to_phys must not be used by drivers.
I have a proper helper for this waiting for users:
http://git.infradead.org/users/hch/misc.git/commitdiff/96a546e7229ec53aadbdb7936d1e5e6cb5958952
If you can confirm the helpers works for you I can try to still sneak
it to Linus for 5.12 to ease the merge pain.
I can try. How do I get a page pointer from a dma_addr_t?
-Paul
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