Merge tag 'drm-misc-next-2020-11-12' of git://anongit.freedesktop.org/drm/drm-misc into drm-next

drm-misc-next for 5.11:

UAPI Changes:

Cross-subsystem Changes:

Core Changes:

 - Remove pgprot_decrypt() before calling io_remap_pfn_range()
 - Revert "drm/dp_mst: Retrieve extended DPCD caps for topology manager"
 - ttm: Add multihop infrastructure
 - doc: Update dma-buf

Driver Changes:

 - amdgpu: Use TTM multihop
 - kmb: select DRM_MIPI_DSI and depend on ARCH_KEEMBAY; Fix build warning;
   Fix typos
 - nouveau: Use TTM multihop; Fix out-of-bounds access
 - radeon: Use TTM multihop
 - ingenic: Search for scaling coefficients to to 102% of screen size

Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201112080115.GA7954@linux-uq9g

2 files changed, 85 insertions, 12 deletions

diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h
index fd1aba545fdf..583a3a1f9447 100644
--- a/include/linux/dma-buf-map.h
+++ b/include/linux/dma-buf-map.h
@@ -7,6 +7,7 @@
 #define __DMA_BUF_MAP_H__
 
 #include <linux/io.h>
+#include <linux/string.h>
 
 /**
  * DOC: overview
@@ -32,6 +33,14 @@
  * accessing the buffer. Use the returned instance and the helper functions
  * to access the buffer's memory in the correct way.
  *
+ * The type :c:type:`struct dma_buf_map <dma_buf_map>` and its helpers are
+ * actually independent from the dma-buf infrastructure. When sharing buffers
+ * among devices, drivers have to know the location of the memory to access
+ * the buffers in a safe way. :c:type:`struct dma_buf_map <dma_buf_map>`
+ * solves this problem for dma-buf and its users. If other drivers or
+ * sub-systems require similar functionality, the type could be generalized
+ * and moved to a more prominent header file.
+ *
  * Open-coding access to :c:type:`struct dma_buf_map <dma_buf_map>` is
  * considered bad style. Rather then accessing its fields directly, use one
  * of the provided helper functions, or implement your own. For example,
@@ -45,6 +54,20 @@
  *
  *	dma_buf_map_set_vaddr(&map. 0xdeadbeaf);
  *
+ * To set an address in I/O memory, use dma_buf_map_set_vaddr_iomem().
+ *
+ * .. code-block:: c
+ *
+ *	dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf);
+ *
+ * Instances of struct dma_buf_map do not have to be cleaned up, but
+ * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings
+ * always refer to system memory.
+ *
+ * .. code-block:: c
+ *
+ *	dma_buf_map_clear(&map);
+ *
  * Test if a mapping is valid with either dma_buf_map_is_set() or
  * dma_buf_map_is_null().
  *
@@ -67,17 +90,19 @@
  *	if (dma_buf_map_is_equal(&sys_map, &io_map))
  *		// always false
  *
- * Instances of struct dma_buf_map do not have to be cleaned up, but
- * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings
- * always refer to system memory.
+ * A set up instance of struct dma_buf_map can be used to access or manipulate
+ * the buffer memory. Depending on the location of the memory, the provided
+ * helpers will pick the correct operations. Data can be copied into the memory
+ * with dma_buf_map_memcpy_to(). The address can be manipulated with
+ * dma_buf_map_incr().
  *
- * The type :c:type:`struct dma_buf_map <dma_buf_map>` and its helpers are
- * actually independent from the dma-buf infrastructure. When sharing buffers
- * among devices, drivers have to know the location of the memory to access
- * the buffers in a safe way. :c:type:`struct dma_buf_map <dma_buf_map>`
- * solves this problem for dma-buf and its users. If other drivers or
- * sub-systems require similar functionality, the type could be generalized
- * and moved to a more prominent header file.
+ * .. code-block:: c
+ *
+ *	const void *src = ...; // source buffer
+ *	size_t len = ...; // length of src
+ *
+ *	dma_buf_map_memcpy_to(&map, src, len);
+ *	dma_buf_map_incr(&map, len); // go to first byte after the memcpy
  */
 
 /**
@@ -119,6 +144,20 @@ static inline void dma_buf_map_set_vaddr(struct dma_buf_map *map, void *vaddr)
 }
 
 /**
+ * dma_buf_map_set_vaddr_iomem - Sets a dma-buf mapping structure to an address in I/O memory
+ * @map:		The dma-buf mapping structure
+ * @vaddr_iomem:	An I/O-memory address
+ *
+ * Sets the address and the I/O-memory flag.
+ */
+static inline void dma_buf_map_set_vaddr_iomem(struct dma_buf_map *map,
+					       void __iomem *vaddr_iomem)
+{
+	map->vaddr_iomem = vaddr_iomem;
+	map->is_iomem = true;
+}
+
+/**
  * dma_buf_map_is_equal - Compares two dma-buf mapping structures for equality
  * @lhs:	The dma-buf mapping structure
  * @rhs:	A dma-buf mapping structure to compare with
@@ -190,4 +229,38 @@ static inline void dma_buf_map_clear(struct dma_buf_map *map)
 	}
 }
 
+/**
+ * dma_buf_map_memcpy_to - Memcpy into dma-buf mapping
+ * @dst:	The dma-buf mapping structure
+ * @src:	The source buffer
+ * @len:	The number of byte in src
+ *
+ * Copies data into a dma-buf mapping. The source buffer is in system
+ * memory. Depending on the buffer's location, the helper picks the correct
+ * method of accessing the memory.
+ */
+static inline void dma_buf_map_memcpy_to(struct dma_buf_map *dst, const void *src, size_t len)
+{
+	if (dst->is_iomem)
+		memcpy_toio(dst->vaddr_iomem, src, len);
+	else
+		memcpy(dst->vaddr, src, len);
+}
+
+/**
+ * dma_buf_map_incr - Increments the address stored in a dma-buf mapping
+ * @map:	The dma-buf mapping structure
+ * @incr:	The number of bytes to increment
+ *
+ * Increments the address stored in a dma-buf mapping. Depending on the
+ * buffer's location, the correct value will be updated.
+ */
+static inline void dma_buf_map_incr(struct dma_buf_map *map, size_t incr)
+{
+	if (map->is_iomem)
+		map->vaddr_iomem += incr;
+	else
+		map->vaddr += incr;
+}
+
 #endif /* __DMA_BUF_MAP_H__ */
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index 03875eaed51a..cf72699cb2bc 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -273,7 +273,7 @@ struct dma_buf_ops {
 
 /**
  * struct dma_buf - shared buffer object
- * @size: size of the buffer
+ * @size: size of the buffer; invariant over the lifetime of the buffer.
  * @file: file pointer used for sharing buffers across, and for refcounting.
  * @attachments: list of dma_buf_attachment that denotes all devices attached,
  *               protected by dma_resv lock.
@@ -405,7 +405,7 @@ struct dma_buf_attachment {
  * @exp_name:	name of the exporter - useful for debugging.
  * @owner:	pointer to exporter module - used for refcounting kernel module
  * @ops:	Attach allocator-defined dma buf ops to the new buffer
- * @size:	Size of the buffer
+ * @size:	Size of the buffer - invariant over the lifetime of the buffer
  * @flags:	mode flags for the file
  * @resv:	reservation-object, NULL to allocate default one
  * @priv:	Attach private data of allocator to this buffer