1/*	$NetBSD: linux_io_mapping.c,v 1.1 2021/12/19 12:28:04 riastradh Exp $	*/
2
3/*-
4 * Copyright (c) 2013-2021 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__KERNEL_RCSID(0, "$NetBSD: linux_io_mapping.c,v 1.1 2021/12/19 12:28:04 riastradh Exp $");
31
32#include <sys/param.h>
33#include <sys/bus.h>
34#include <sys/kmem.h>
35#include <sys/systm.h>
36#include <sys/mman.h>
37
38#include <uvm/uvm_extern.h>
39
40#include <linux/io-mapping.h>
41
42bool
43bus_space_io_mapping_init_wc(bus_space_tag_t bst, struct io_mapping *mapping,
44    bus_addr_t addr, bus_size_t size)
45{
46	bus_size_t offset;
47
48	KASSERT(PAGE_SIZE <= size);
49	KASSERT(0 == (size & (PAGE_SIZE - 1)));
50	KASSERT(__type_fit(off_t, size));
51
52	/*
53	 * XXX For x86: Reserve the region (bus_space_reserve) and set
54	 * an MTRR to make it write-combining.  Doesn't matter if we
55	 * have PAT and we use pmap_kenter_pa, but matters if we don't
56	 * have PAT or if we later make this use direct map.
57	 */
58
59	/* Make sure the region is mappable.  */
60	for (offset = 0; offset < size; offset += PAGE_SIZE) {
61		if (bus_space_mmap(bst, addr, offset, PROT_READ|PROT_WRITE,
62			BUS_SPACE_MAP_LINEAR|BUS_SPACE_MAP_PREFETCHABLE)
63		    == (paddr_t)-1)
64			return false;
65	}
66
67	/* Initialize the mapping record.  */
68	mapping->diom_bst = bst;
69	mapping->base = addr;
70	mapping->size = size;
71	mapping->diom_atomic = false;
72
73	/* Allocate kva for one page.  */
74	mapping->diom_va = uvm_km_alloc(kernel_map, PAGE_SIZE, PAGE_SIZE,
75	    UVM_KMF_VAONLY | UVM_KMF_WAITVA);
76	KASSERT(mapping->diom_va != 0);
77
78	return true;
79}
80
81void
82io_mapping_fini(struct io_mapping *mapping)
83{
84
85	KASSERT(!mapping->diom_atomic);
86
87	uvm_km_free(kernel_map, mapping->diom_va, PAGE_SIZE, UVM_KMF_VAONLY);
88	mapping->diom_va = 0;	/* paranoia */
89}
90
91struct io_mapping *
92bus_space_io_mapping_create_wc(bus_space_tag_t bst, bus_addr_t addr,
93    bus_size_t size)
94{
95	struct io_mapping *mapping;
96
97	mapping = kmem_alloc(sizeof(*mapping), KM_SLEEP);
98	if (!bus_space_io_mapping_init_wc(bst, mapping, addr, size)) {
99		kmem_free(mapping, sizeof(*mapping));
100		return NULL;
101	}
102
103	return mapping;
104}
105
106void
107io_mapping_free(struct io_mapping *mapping)
108{
109
110	io_mapping_fini(mapping);
111	kmem_free(mapping, sizeof(*mapping));
112}
113
114void *
115io_mapping_map_wc(struct io_mapping *mapping, bus_addr_t offset,
116    bus_size_t size)
117{
118	bus_size_t pg, npgs = size >> PAGE_SHIFT;
119	vaddr_t va;
120	paddr_t cookie;
121
122	KASSERT(0 == (offset & (PAGE_SIZE - 1)));
123	KASSERT(PAGE_SIZE <= mapping->size);
124	KASSERT(offset <= (mapping->size - PAGE_SIZE));
125	KASSERT(__type_fit(off_t, offset));
126
127	va = uvm_km_alloc(kernel_map, size, PAGE_SIZE,
128	    UVM_KMF_VAONLY|UVM_KMF_WAITVA);
129	KASSERT(va != mapping->diom_va);
130	for (pg = 0; pg < npgs; pg++) {
131		cookie = bus_space_mmap(mapping->diom_bst, mapping->base,
132		    offset + pg*PAGE_SIZE,
133		    PROT_READ|PROT_WRITE,
134		    BUS_SPACE_MAP_LINEAR|BUS_SPACE_MAP_PREFETCHABLE);
135		KASSERT(cookie != (paddr_t)-1);
136
137		pmap_kenter_pa(va + pg*PAGE_SIZE, pmap_phys_address(cookie),
138		    PROT_READ|PROT_WRITE, pmap_mmap_flags(cookie));
139	}
140	pmap_update(pmap_kernel());
141
142	return (void *)va;
143}
144
145void
146io_mapping_unmap(struct io_mapping *mapping, void *ptr, bus_size_t size)
147{
148	vaddr_t va = (vaddr_t)ptr;
149
150	KASSERT(mapping->diom_va != va);
151
152	pmap_kremove(va, size);
153	pmap_update(pmap_kernel());
154
155	uvm_km_free(kernel_map, va, size, UVM_KMF_VAONLY);
156}
157
158void *
159io_mapping_map_atomic_wc(struct io_mapping *mapping, bus_addr_t offset)
160{
161	paddr_t cookie;
162
163	KASSERT(0 == (offset & (PAGE_SIZE - 1)));
164	KASSERT(PAGE_SIZE <= mapping->size);
165	KASSERT(offset <= (mapping->size - PAGE_SIZE));
166	KASSERT(__type_fit(off_t, offset));
167	KASSERT(!mapping->diom_atomic);
168
169	cookie = bus_space_mmap(mapping->diom_bst, mapping->base, offset,
170	    PROT_READ|PROT_WRITE,
171	    BUS_SPACE_MAP_LINEAR|BUS_SPACE_MAP_PREFETCHABLE);
172	KASSERT(cookie != (paddr_t)-1);
173
174	pmap_kenter_pa(mapping->diom_va, pmap_phys_address(cookie),
175	    PROT_READ|PROT_WRITE, pmap_mmap_flags(cookie));
176	pmap_update(pmap_kernel());
177
178	mapping->diom_atomic = true;
179	return (void *)mapping->diom_va;
180}
181
182void
183io_mapping_unmap_atomic(struct io_mapping *mapping, void *ptr __diagused)
184{
185
186	KASSERT(mapping->diom_atomic);
187	KASSERT(mapping->diom_va == (vaddr_t)ptr);
188
189	pmap_kremove(mapping->diom_va, PAGE_SIZE);
190	pmap_update(pmap_kernel());
191
192	mapping->diom_atomic = false;
193}
194