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path: root/drivers/gpu/drm/i915/i915_mm.c
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Diffstat (limited to 'drivers/gpu/drm/i915/i915_mm.c')
-rw-r--r--drivers/gpu/drm/i915/i915_mm.c69
1 files changed, 69 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_mm.c b/drivers/gpu/drm/i915/i915_mm.c
index 318562ce64c0..b6376b25ef63 100644
--- a/drivers/gpu/drm/i915/i915_mm.c
+++ b/drivers/gpu/drm/i915/i915_mm.c
@@ -33,6 +33,9 @@ struct remap_pfn {
struct mm_struct *mm;
unsigned long pfn;
pgprot_t prot;
+
+ struct sgt_iter sgt;
+ resource_size_t iobase;
};
static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
@@ -46,6 +49,35 @@ static int remap_pfn(pte_t *pte, unsigned long addr, void *data)
return 0;
}
+#define use_dma(io) ((io) != -1)
+
+static inline unsigned long sgt_pfn(const struct remap_pfn *r)
+{
+ if (use_dma(r->iobase))
+ return (r->sgt.dma + r->sgt.curr + r->iobase) >> PAGE_SHIFT;
+ else
+ return r->sgt.pfn + (r->sgt.curr >> PAGE_SHIFT);
+}
+
+static int remap_sg(pte_t *pte, unsigned long addr, void *data)
+{
+ struct remap_pfn *r = data;
+
+ if (GEM_WARN_ON(!r->sgt.pfn))
+ return -EINVAL;
+
+ /* Special PTE are not associated with any struct page */
+ set_pte_at(r->mm, addr, pte,
+ pte_mkspecial(pfn_pte(sgt_pfn(r), r->prot)));
+ r->pfn++; /* track insertions in case we need to unwind later */
+
+ r->sgt.curr += PAGE_SIZE;
+ if (r->sgt.curr >= r->sgt.max)
+ r->sgt = __sgt_iter(__sg_next(r->sgt.sgp), use_dma(r->iobase));
+
+ return 0;
+}
+
/**
* remap_io_mapping - remap an IO mapping to userspace
* @vma: user vma to map to
@@ -80,3 +112,40 @@ int remap_io_mapping(struct vm_area_struct *vma,
return 0;
}
+
+/**
+ * remap_io_sg - remap an IO mapping to userspace
+ * @vma: user vma to map to
+ * @addr: target user address to start at
+ * @size: size of map area
+ * @sgl: Start sg entry
+ * @iobase: Use stored dma address offset by this address or pfn if -1
+ *
+ * Note: this is only safe if the mm semaphore is held when called.
+ */
+int remap_io_sg(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long size,
+ struct scatterlist *sgl, resource_size_t iobase)
+{
+ struct remap_pfn r = {
+ .mm = vma->vm_mm,
+ .prot = vma->vm_page_prot,
+ .sgt = __sgt_iter(sgl, use_dma(iobase)),
+ .iobase = iobase,
+ };
+ int err;
+
+ /* We rely on prevalidation of the io-mapping to skip track_pfn(). */
+ GEM_BUG_ON((vma->vm_flags & EXPECTED_FLAGS) != EXPECTED_FLAGS);
+
+ if (!use_dma(iobase))
+ flush_cache_range(vma, addr, size);
+
+ err = apply_to_page_range(r.mm, addr, size, remap_sg, &r);
+ if (unlikely(err)) {
+ zap_vma_ptes(vma, addr, r.pfn << PAGE_SHIFT);
+ return err;
+ }
+
+ return 0;
+}