v4.19.13 snapshot.
diff --git a/include/linux/io-mapping.h b/include/linux/io-mapping.h
new file mode 100644
index 0000000..58df02b
--- /dev/null
+++ b/include/linux/io-mapping.h
@@ -0,0 +1,202 @@
+/*
+ * Copyright © 2008 Keith Packard <keithp@keithp.com>
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _LINUX_IO_MAPPING_H
+#define _LINUX_IO_MAPPING_H
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/bug.h>
+#include <linux/io.h>
+#include <asm/page.h>
+
+/*
+ * The io_mapping mechanism provides an abstraction for mapping
+ * individual pages from an io device to the CPU in an efficient fashion.
+ *
+ * See Documentation/io-mapping.txt
+ */
+
+struct io_mapping {
+ resource_size_t base;
+ unsigned long size;
+ pgprot_t prot;
+ void __iomem *iomem;
+};
+
+#ifdef CONFIG_HAVE_ATOMIC_IOMAP
+
+#include <asm/iomap.h>
+/*
+ * For small address space machines, mapping large objects
+ * into the kernel virtual space isn't practical. Where
+ * available, use fixmap support to dynamically map pages
+ * of the object at run time.
+ */
+
+static inline struct io_mapping *
+io_mapping_init_wc(struct io_mapping *iomap,
+ resource_size_t base,
+ unsigned long size)
+{
+ pgprot_t prot;
+
+ if (iomap_create_wc(base, size, &prot))
+ return NULL;
+
+ iomap->base = base;
+ iomap->size = size;
+ iomap->prot = prot;
+ return iomap;
+}
+
+static inline void
+io_mapping_fini(struct io_mapping *mapping)
+{
+ iomap_free(mapping->base, mapping->size);
+}
+
+/* Atomic map/unmap */
+static inline void __iomem *
+io_mapping_map_atomic_wc(struct io_mapping *mapping,
+ unsigned long offset)
+{
+ resource_size_t phys_addr;
+ unsigned long pfn;
+
+ BUG_ON(offset >= mapping->size);
+ phys_addr = mapping->base + offset;
+ pfn = (unsigned long) (phys_addr >> PAGE_SHIFT);
+ return iomap_atomic_prot_pfn(pfn, mapping->prot);
+}
+
+static inline void
+io_mapping_unmap_atomic(void __iomem *vaddr)
+{
+ iounmap_atomic(vaddr);
+}
+
+static inline void __iomem *
+io_mapping_map_wc(struct io_mapping *mapping,
+ unsigned long offset,
+ unsigned long size)
+{
+ resource_size_t phys_addr;
+
+ BUG_ON(offset >= mapping->size);
+ phys_addr = mapping->base + offset;
+
+ return ioremap_wc(phys_addr, size);
+}
+
+static inline void
+io_mapping_unmap(void __iomem *vaddr)
+{
+ iounmap(vaddr);
+}
+
+#else
+
+#include <linux/uaccess.h>
+#include <asm/pgtable.h>
+
+/* Create the io_mapping object*/
+static inline struct io_mapping *
+io_mapping_init_wc(struct io_mapping *iomap,
+ resource_size_t base,
+ unsigned long size)
+{
+ iomap->base = base;
+ iomap->size = size;
+ iomap->iomem = ioremap_wc(base, size);
+#if defined(pgprot_noncached_wc) /* archs can't agree on a name ... */
+ iomap->prot = pgprot_noncached_wc(PAGE_KERNEL);
+#elif defined(pgprot_writecombine)
+ iomap->prot = pgprot_writecombine(PAGE_KERNEL);
+#else
+ iomap->prot = pgprot_noncached(PAGE_KERNEL);
+#endif
+
+ return iomap;
+}
+
+static inline void
+io_mapping_fini(struct io_mapping *mapping)
+{
+ iounmap(mapping->iomem);
+}
+
+/* Non-atomic map/unmap */
+static inline void __iomem *
+io_mapping_map_wc(struct io_mapping *mapping,
+ unsigned long offset,
+ unsigned long size)
+{
+ return mapping->iomem + offset;
+}
+
+static inline void
+io_mapping_unmap(void __iomem *vaddr)
+{
+}
+
+/* Atomic map/unmap */
+static inline void __iomem *
+io_mapping_map_atomic_wc(struct io_mapping *mapping,
+ unsigned long offset)
+{
+ preempt_disable();
+ pagefault_disable();
+ return io_mapping_map_wc(mapping, offset, PAGE_SIZE);
+}
+
+static inline void
+io_mapping_unmap_atomic(void __iomem *vaddr)
+{
+ io_mapping_unmap(vaddr);
+ pagefault_enable();
+ preempt_enable();
+}
+
+#endif /* HAVE_ATOMIC_IOMAP */
+
+static inline struct io_mapping *
+io_mapping_create_wc(resource_size_t base,
+ unsigned long size)
+{
+ struct io_mapping *iomap;
+
+ iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
+ if (!iomap)
+ return NULL;
+
+ if (!io_mapping_init_wc(iomap, base, size)) {
+ kfree(iomap);
+ return NULL;
+ }
+
+ return iomap;
+}
+
+static inline void
+io_mapping_free(struct io_mapping *iomap)
+{
+ io_mapping_fini(iomap);
+ kfree(iomap);
+}
+
+#endif /* _LINUX_IO_MAPPING_H */