/*
   * 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 <asm/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
   */
  
  #ifdef CONFIG_HAVE_ATOMIC_IOMAP
  
  #include <asm/iomap.h>
  
  struct io_mapping {
  	resource_size_t base;
  	unsigned long size;
  	pgprot_t prot;
  };
  
  /*
   * 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_create_wc(resource_size_t base, unsigned long size)
  {
  	struct io_mapping *iomap;
  	pgprot_t prot;
  
  	iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
  	if (!iomap)
  		goto out_err;
  
  	if (iomap_create_wc(base, size, &prot))
  		goto out_free;
  
  	iomap->base = base;
  	iomap->size = size;
  	iomap->prot = prot;
  	return iomap;
  
  out_free:
  	kfree(iomap);
  out_err:
  	return NULL;
  }
  
  static inline void
  io_mapping_free(struct io_mapping *mapping)
  {
  	iomap_free(mapping->base, mapping->size);
  	kfree(mapping);
  }
  
  /* 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)
  {
  	resource_size_t phys_addr;
  
  	BUG_ON(offset >= mapping->size);
  	phys_addr = mapping->base + offset;
  
  	return ioremap_wc(phys_addr, PAGE_SIZE);
  }
  
  static inline void
  io_mapping_unmap(void __iomem *vaddr)
  {
  	iounmap(vaddr);
  }
  
  #else
  
  #include <linux/uaccess.h>
  
  /* this struct isn't actually defined anywhere */
  struct io_mapping;
  
  /* Create the io_mapping object*/
  static inline struct io_mapping *
  io_mapping_create_wc(resource_size_t base, unsigned long size)
  {
  	return (struct io_mapping __force *) ioremap_wc(base, size);
  }
  
  static inline void
  io_mapping_free(struct io_mapping *mapping)
  {
  	iounmap((void __force __iomem *) mapping);
  }
  
  /* Atomic map/unmap */
  static inline void __iomem *
  io_mapping_map_atomic_wc(struct io_mapping *mapping,
  			 unsigned long offset)
  {
  	pagefault_disable();
  	return ((char __force __iomem *) mapping) + offset;
  }
  
  static inline void
  io_mapping_unmap_atomic(void __iomem *vaddr)
  {
  	pagefault_enable();
  }
  
  /* Non-atomic map/unmap */
  static inline void __iomem *
  io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
  {
  	return ((char __force __iomem *) mapping) + offset;
  }
  
  static inline void
  io_mapping_unmap(void __iomem *vaddr)
  {
  }
  
  #endif /* HAVE_ATOMIC_IOMAP */
  
  #endif /* _LINUX_IO_MAPPING_H */