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io-mapping.h revision 1.5 
      1 /*	$NetBSD: io-mapping.h,v 1.5 2015/02/25 14:02:43 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2013 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #ifndef _LINUX_IO_MAPPING_H_
     33 #define _LINUX_IO_MAPPING_H_
     34 
     35 #include <sys/param.h>
     36 #include <sys/bus.h>
     37 #include <sys/kmem.h>
     38 #include <sys/systm.h>
     39 #include <sys/mman.h>
     40 
     41 #include <uvm/uvm_extern.h>
     42 
     43 struct io_mapping {
     44 	bus_space_tag_t		diom_bst;
     45 	bus_addr_t		diom_addr;
     46 	bus_size_t		diom_size;
     47 	vaddr_t			diom_va;
     48 	bool			diom_mapped;
     49 };
     50 
     51 static inline struct io_mapping *
     52 bus_space_io_mapping_create_wc(bus_space_tag_t bst, bus_addr_t addr,
     53     bus_size_t size)
     54 {
     55 	struct io_mapping *mapping;
     56 	bus_size_t offset;
     57 
     58 	KASSERT(PAGE_SIZE <= size);
     59 	KASSERT(0 == (size & (PAGE_SIZE - 1)));
     60 	KASSERT(__type_fit(off_t, size));
     61 
     62 	/*
     63 	 * XXX For x86: Reserve the region (bus_space_reserve) and set
     64 	 * an MTRR to make it write-combining.  Doesn't matter if we
     65 	 * have PAT and we use pmap_kenter_pa, but matters if we don't
     66 	 * have PAT or if we later make this use direct map.
     67 	 */
     68 
     69 	/* Make sure the region is mappable.  */
     70 	for (offset = 0; offset < size; offset += PAGE_SIZE) {
     71 		if (bus_space_mmap(bst, addr, offset, PROT_READ|PROT_WRITE,
     72 			BUS_SPACE_MAP_LINEAR|BUS_SPACE_MAP_PREFETCHABLE)
     73 		    == (paddr_t)-1)
     74 			return NULL;
     75 	}
     76 
     77 	/* Create a mapping record.  */
     78 	mapping = kmem_alloc(sizeof(*mapping), KM_SLEEP);
     79 	mapping->diom_bst = bst;
     80 	mapping->diom_addr = addr;
     81 	mapping->diom_size = size;
     82 	mapping->diom_mapped = false;
     83 
     84 	/* Allocate kva for one page.  */
     85 	mapping->diom_va = uvm_km_alloc(kernel_map, PAGE_SIZE, PAGE_SIZE,
     86 	    UVM_KMF_VAONLY | UVM_KMF_WAITVA);
     87 	KASSERT(mapping->diom_va != 0);
     88 
     89 	return mapping;
     90 }
     91 
     92 static inline void
     93 io_mapping_free(struct io_mapping *mapping)
     94 {
     95 
     96 	KASSERT(!mapping->diom_mapped);
     97 
     98 	uvm_km_free(kernel_map, mapping->diom_va, PAGE_SIZE, UVM_KMF_VAONLY);
     99 	kmem_free(mapping, sizeof(*mapping));
    100 }
    101 
    102 static inline void *
    103 io_mapping_map_wc(struct io_mapping *mapping, unsigned long offset)
    104 {
    105 	paddr_t cookie;
    106 
    107 	KASSERT(0 == (offset & (PAGE_SIZE - 1)));
    108 	KASSERT(PAGE_SIZE <= mapping->diom_size);
    109 	KASSERT(offset <= (mapping->diom_size - PAGE_SIZE));
    110 	KASSERT(__type_fit(off_t, offset));
    111 	KASSERT(!mapping->diom_mapped);
    112 
    113 	cookie = bus_space_mmap(mapping->diom_bst, mapping->diom_addr, offset,
    114 	    PROT_READ|PROT_WRITE,
    115 	    BUS_SPACE_MAP_LINEAR|BUS_SPACE_MAP_PREFETCHABLE);
    116 	KASSERT(cookie != (paddr_t)-1);
    117 
    118 	pmap_kenter_pa(mapping->diom_va, pmap_phys_address(cookie),
    119 	    PROT_READ|PROT_WRITE, pmap_mmap_flags(cookie));
    120 	pmap_update(pmap_kernel());
    121 
    122 	mapping->diom_mapped = true;
    123 	return (void *)mapping->diom_va;
    124 }
    125 
    126 static inline void
    127 io_mapping_unmap(struct io_mapping *mapping, void *ptr __diagused)
    128 {
    129 
    130 	KASSERT(mapping->diom_mapped);
    131 	KASSERT(mapping->diom_va == (vaddr_t)ptr);
    132 
    133 	pmap_kremove(mapping->diom_va, PAGE_SIZE);
    134 	pmap_update(pmap_kernel());
    135 
    136 	mapping->diom_mapped = false;
    137 }
    138 
    139 static inline void *
    140 io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
    141 {
    142 
    143 	return io_mapping_map_wc(mapping, offset);
    144 }
    145 
    146 static inline void
    147 io_mapping_unmap_atomic(struct io_mapping *mapping, void *ptr)
    148 {
    149 
    150 	io_mapping_unmap(mapping, ptr);
    151 }
    152 
    153 #endif  /* _LINUX_IO_MAPPING_H_ */
    154