Edit File: io-mapping.h
/* * 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 */ 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 */