1 /* $NetBSD: fdt_iommu.c,v 1.1 2021/09/04 12:34:39 jmcneill Exp $ */
2
3 /*-
4 * Copyright (c) 2021 Jared McNeill <jmcneill@invisible.ca>
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 AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __KERNEL_RCSID(0, "$NetBSD: fdt_iommu.c,v 1.1 2021/09/04 12:34:39 jmcneill Exp $");
31
32 #include <sys/param.h>
33 #include <sys/bus.h>
34 #include <sys/kmem.h>
35 #include <sys/queue.h>
36
37 #include <libfdt.h>
38 #include <dev/fdt/fdtvar.h>
39
40 struct fdtbus_iommu {
41 device_t iommu_dev;
42 int iommu_phandle;
43 const struct fdtbus_iommu_func *iommu_funcs;
44 u_int iommu_cells;
45 LIST_ENTRY(fdtbus_iommu) iommu_next;
46 };
47
48 static LIST_HEAD(, fdtbus_iommu) fdtbus_iommus =
49 LIST_HEAD_INITIALIZER(fdtbus_iommus);
50
51 /*
52 * fdtbus_get_iommu --
53 *
54 * Return the iommu registered with the specified node, or NULL if
55 * not found.
56 */
57 static struct fdtbus_iommu *
fdtbus_get_iommu(int phandle)58 fdtbus_get_iommu(int phandle)
59 {
60 struct fdtbus_iommu *iommu;
61
62 LIST_FOREACH(iommu, &fdtbus_iommus, iommu_next) {
63 if (iommu->iommu_phandle == phandle) {
64 return iommu;
65 }
66 }
67
68 return NULL;
69 }
70
71 /*
72 * fdtbus_register_iommu --
73 *
74 * Register an IOMMU on the specified node.
75 */
76 int
fdtbus_register_iommu(device_t dev,int phandle,const struct fdtbus_iommu_func * funcs)77 fdtbus_register_iommu(device_t dev, int phandle,
78 const struct fdtbus_iommu_func *funcs)
79 {
80 struct fdtbus_iommu *iommu;
81 u_int cells;
82
83 if (funcs == NULL || funcs->map == NULL) {
84 return EINVAL;
85 }
86
87 if (of_getprop_uint32(phandle, "#iommu-cells", &cells) != 0) {
88 return ENXIO;
89 }
90
91 if (fdtbus_get_iommu(phandle) != NULL) {
92 return EEXIST;
93 }
94
95 iommu = kmem_alloc(sizeof(*iommu), KM_SLEEP);
96 iommu->iommu_dev = dev;
97 iommu->iommu_phandle = phandle;
98 iommu->iommu_funcs = funcs;
99 iommu->iommu_cells = cells;
100
101 LIST_INSERT_HEAD(&fdtbus_iommus, iommu, iommu_next);
102
103 return 0;
104 }
105
106 /*
107 * fdtbus_iommu_map --
108 *
109 * Get a bus dma tag that is translated by any iommus specified by
110 * the device tree. The `index` property refers to the N-th item
111 * in the list of IOMMUs specified in the "iommus" property. If an
112 * IOMMU is not found, the original bus dma tag is returned.
113 */
114 bus_dma_tag_t
fdtbus_iommu_map(int phandle,u_int index,bus_dma_tag_t dmat)115 fdtbus_iommu_map(int phandle, u_int index, bus_dma_tag_t dmat)
116 {
117 struct fdtbus_iommu *iommu;
118 const u_int *p;
119 u_int n, cells;
120 int len, resid;
121
122 p = fdtbus_get_prop(phandle, "iommus", &len);
123 if (p == NULL) {
124 return dmat;
125 }
126
127 for (n = 0, resid = len; resid > 0; n++) {
128 const int iommu_phandle =
129 fdtbus_get_phandle_from_native(be32toh(p[0]));
130 if (of_getprop_uint32(iommu_phandle, "#iommu-cells", &cells)) {
131 break;
132 }
133 if (n == index) {
134 iommu = fdtbus_get_iommu(iommu_phandle);
135 if (iommu == NULL) {
136 break;
137 }
138 return iommu->iommu_funcs->map(iommu->iommu_dev,
139 cells > 0 ? &p[1] : NULL, dmat);
140 }
141 resid -= (cells + 1) * 4;
142 p += cells + 1;
143 }
144
145 return dmat;
146 }
147
148 /*
149 * fdtbus_iommu_map_pci --
150 *
151 * Get a bus dma tag that is translated by any iommus specified by
152 * the device tree for PCI devices. The `rid` param is the requester
153 * ID. Returns a (maybe translated) dma tag.
154 */
155 bus_dma_tag_t
fdtbus_iommu_map_pci(int phandle,uint32_t rid,bus_dma_tag_t dmat)156 fdtbus_iommu_map_pci(int phandle, uint32_t rid, bus_dma_tag_t dmat)
157 {
158 struct fdtbus_iommu *iommu;
159 uint32_t map_mask;
160 const u_int *p;
161 u_int cells;
162 int len;
163
164 len = 0;
165 p = fdtbus_get_prop(phandle, "iommu-map", &len);
166 KASSERT(p != NULL || len == 0);
167
168 if (of_getprop_uint32(phandle, "iommu-map-mask", &map_mask) == 0) {
169 rid &= map_mask;
170 }
171
172 while (len >= 4) {
173 const u_int rid_base = be32toh(*p++);
174 const int iommu_phandle =
175 fdtbus_get_phandle_from_native(be32toh(*p++));
176 const u_int iommu_base = be32toh(*p++);
177 const u_int length = be32toh(*p++);
178 len -= 4;
179
180 if (iommu_phandle <= 0) {
181 continue;
182 }
183 if (of_getprop_uint32(iommu_phandle, "#iommu-cells", &cells)) {
184 continue;
185 }
186 if (cells != 1) {
187 /*
188 * The pci-iommu bindings expect iommu references with
189 * exactly one specifier cell.
190 */
191 continue;
192 }
193 iommu = fdtbus_get_iommu(iommu_phandle);
194 if (iommu == NULL) {
195 continue;
196 }
197
198 if (rid >= rid_base && rid < rid_base + length) {
199 const uint32_t sid = rid - rid_base + iommu_base;
200 return iommu->iommu_funcs->map(iommu->iommu_dev,
201 &sid, dmat);
202 }
203 }
204
205 return dmat;
206 }
207