/* * 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) { 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 *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 */