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/*
* 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 <asm/io.h>
#include <asm/page.h>
#include <asm/iomap.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
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;
if (!is_io_mapping_possible(base, size))
return NULL;
iomap = kmalloc(sizeof(*iomap), GFP_KERNEL);
if (!iomap)
return NULL;
iomap->base = base;
iomap->size = size;
iomap->prot = pgprot_writecombine(__pgprot(__PAGE_KERNEL));
return iomap;
}
static inline void
io_mapping_free(struct io_mapping *mapping)
{
kfree(mapping);
}
/* Atomic map/unmap */
static inline void *
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, KM_USER0, mapping->prot);
}
static inline void
io_mapping_unmap_atomic(void *vaddr)
{
iounmap_atomic(vaddr, KM_USER0);
}
static inline void *
io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
{
BUG_ON(offset >= mapping->size);
resource_size_t phys_addr = mapping->base + offset;
return ioremap_wc(phys_addr, PAGE_SIZE);
}
static inline void
io_mapping_unmap(void *vaddr)
{
iounmap(vaddr);
}
#else
/* 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 *) ioremap_wc(base, size);
}
static inline void
io_mapping_free(struct io_mapping *mapping)
{
iounmap(mapping);
}
/* Atomic map/unmap */
static inline void *
io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
{
return ((char *) mapping) + offset;
}
static inline void
io_mapping_unmap_atomic(void *vaddr)
{
}
/* Non-atomic map/unmap */
static inline void *
io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
{
return ((char *) mapping) + offset;
}
static inline void
io_mapping_unmap(void *vaddr)
{
}
#endif /* HAVE_ATOMIC_IOMAP */
#endif /* _LINUX_IO_MAPPING_H */
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