Viewing file:  io-mapping.h (3.77 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright © 2008 Keith Packard <keithp@keithp.com>
*/
#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->iomem = ioremap_wc(base, size);
if (!iomap->iomem)
return NULL;
iomap->base = base;
iomap->size = 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 */
|