v4.19.13 snapshot.
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
new file mode 100644
index 0000000..f247e8a
--- /dev/null
+++ b/include/linux/dma-contiguous.h
@@ -0,0 +1,164 @@
+#ifndef __LINUX_CMA_H
+#define __LINUX_CMA_H
+
+/*
+ * Contiguous Memory Allocator for DMA mapping framework
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Written by:
+ * Marek Szyprowski <m.szyprowski@samsung.com>
+ * Michal Nazarewicz <mina86@mina86.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+/*
+ * Contiguous Memory Allocator
+ *
+ * The Contiguous Memory Allocator (CMA) makes it possible to
+ * allocate big contiguous chunks of memory after the system has
+ * booted.
+ *
+ * Why is it needed?
+ *
+ * Various devices on embedded systems have no scatter-getter and/or
+ * IO map support and require contiguous blocks of memory to
+ * operate. They include devices such as cameras, hardware video
+ * coders, etc.
+ *
+ * Such devices often require big memory buffers (a full HD frame
+ * is, for instance, more then 2 mega pixels large, i.e. more than 6
+ * MB of memory), which makes mechanisms such as kmalloc() or
+ * alloc_page() ineffective.
+ *
+ * At the same time, a solution where a big memory region is
+ * reserved for a device is suboptimal since often more memory is
+ * reserved then strictly required and, moreover, the memory is
+ * inaccessible to page system even if device drivers don't use it.
+ *
+ * CMA tries to solve this issue by operating on memory regions
+ * where only movable pages can be allocated from. This way, kernel
+ * can use the memory for pagecache and when device driver requests
+ * it, allocated pages can be migrated.
+ *
+ * Driver usage
+ *
+ * CMA should not be used by the device drivers directly. It is
+ * only a helper framework for dma-mapping subsystem.
+ *
+ * For more information, see kernel-docs in kernel/dma/contiguous.c
+ */
+
+#ifdef __KERNEL__
+
+#include <linux/device.h>
+
+struct cma;
+struct page;
+
+#ifdef CONFIG_DMA_CMA
+
+extern struct cma *dma_contiguous_default_area;
+
+static inline struct cma *dev_get_cma_area(struct device *dev)
+{
+ if (dev && dev->cma_area)
+ return dev->cma_area;
+ return dma_contiguous_default_area;
+}
+
+static inline void dev_set_cma_area(struct device *dev, struct cma *cma)
+{
+ if (dev)
+ dev->cma_area = cma;
+}
+
+static inline void dma_contiguous_set_default(struct cma *cma)
+{
+ dma_contiguous_default_area = cma;
+}
+
+void dma_contiguous_reserve(phys_addr_t addr_limit);
+
+int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+ phys_addr_t limit, struct cma **res_cma,
+ bool fixed);
+
+/**
+ * dma_declare_contiguous() - reserve area for contiguous memory handling
+ * for particular device
+ * @dev: Pointer to device structure.
+ * @size: Size of the reserved memory.
+ * @base: Start address of the reserved memory (optional, 0 for any).
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ *
+ * This function reserves memory for specified device. It should be
+ * called by board specific code when early allocator (memblock or bootmem)
+ * is still activate.
+ */
+
+static inline int dma_declare_contiguous(struct device *dev, phys_addr_t size,
+ phys_addr_t base, phys_addr_t limit)
+{
+ struct cma *cma;
+ int ret;
+ ret = dma_contiguous_reserve_area(size, base, limit, &cma, true);
+ if (ret == 0)
+ dev_set_cma_area(dev, cma);
+
+ return ret;
+}
+
+struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
+ unsigned int order, bool no_warn);
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+ int count);
+
+#else
+
+static inline struct cma *dev_get_cma_area(struct device *dev)
+{
+ return NULL;
+}
+
+static inline void dev_set_cma_area(struct device *dev, struct cma *cma) { }
+
+static inline void dma_contiguous_set_default(struct cma *cma) { }
+
+static inline void dma_contiguous_reserve(phys_addr_t limit) { }
+
+static inline int dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
+ phys_addr_t limit, struct cma **res_cma,
+ bool fixed)
+{
+ return -ENOSYS;
+}
+
+static inline
+int dma_declare_contiguous(struct device *dev, phys_addr_t size,
+ phys_addr_t base, phys_addr_t limit)
+{
+ return -ENOSYS;
+}
+
+static inline
+struct page *dma_alloc_from_contiguous(struct device *dev, size_t count,
+ unsigned int order, bool no_warn)
+{
+ return NULL;
+}
+
+static inline
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+ int count)
+{
+ return false;
+}
+
+#endif
+
+#endif
+
+#endif