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