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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Thunderbolt driver - capabilities lookup
4 *
5 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
6 * Copyright (C) 2018, Intel Corporation
7 */
8
9#include <linux/slab.h>
10#include <linux/errno.h>
11
12#include "tb.h"
13
14#define CAP_OFFSET_MAX 0xff
15#define VSE_CAP_OFFSET_MAX 0xffff
16#define TMU_ACCESS_EN BIT(20)
17
18static int tb_port_enable_tmu(struct tb_port *port, bool enable)
19{
20 struct tb_switch *sw = port->sw;
21 u32 value, offset;
22 int ret;
23
24 /*
25 * Legacy devices need to have TMU access enabled before port
26 * space can be fully accessed.
27 */
28 if (tb_switch_is_light_ridge(sw))
29 offset = 0x26;
30 else if (tb_switch_is_eagle_ridge(sw))
31 offset = 0x2a;
32 else
33 return 0;
34
35 ret = tb_sw_read(sw, &value, TB_CFG_SWITCH, offset, 1);
36 if (ret)
37 return ret;
38
39 if (enable)
40 value |= TMU_ACCESS_EN;
41 else
42 value &= ~TMU_ACCESS_EN;
43
44 return tb_sw_write(sw, &value, TB_CFG_SWITCH, offset, 1);
45}
46
47static void tb_port_dummy_read(struct tb_port *port)
48{
49 /*
50 * When reading from next capability pointer location in port
51 * config space the read data is not cleared on LR. To avoid
52 * reading stale data on next read perform one dummy read after
53 * port capabilities are walked.
54 */
55 if (tb_switch_is_light_ridge(port->sw)) {
56 u32 dummy;
57
58 tb_port_read(port, &dummy, TB_CFG_PORT, 0, 1);
59 }
60}
61
62/**
63 * tb_port_next_cap() - Return next capability in the linked list
64 * @port: Port to find the capability for
65 * @offset: Previous capability offset (%0 for start)
66 *
67 * Returns dword offset of the next capability in port config space
68 * capability list and returns it. Passing %0 returns the first entry in
69 * the capability list. If no next capability is found returns %0. In case
70 * of failure returns negative errno.
71 */
72int tb_port_next_cap(struct tb_port *port, unsigned int offset)
73{
74 struct tb_cap_any header;
75 int ret;
76
77 if (!offset)
78 return port->config.first_cap_offset;
79
80 ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
81 if (ret)
82 return ret;
83
84 return header.basic.next;
85}
86
87static int __tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
88{
89 int offset = 0;
90
91 do {
92 struct tb_cap_any header;
93 int ret;
94
95 offset = tb_port_next_cap(port, offset);
96 if (offset < 0)
97 return offset;
98
99 ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
100 if (ret)
101 return ret;
102
103 if (header.basic.cap == cap)
104 return offset;
105 } while (offset > 0);
106
107 return -ENOENT;
108}
109
110/**
111 * tb_port_find_cap() - Find port capability
112 * @port: Port to find the capability for
113 * @cap: Capability to look
114 *
115 * Returns offset to start of capability or %-ENOENT if no such
116 * capability was found. Negative errno is returned if there was an
117 * error.
118 */
119int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
120{
121 int ret;
122
123 ret = tb_port_enable_tmu(port, true);
124 if (ret)
125 return ret;
126
127 ret = __tb_port_find_cap(port, cap);
128
129 tb_port_dummy_read(port);
130 tb_port_enable_tmu(port, false);
131
132 return ret;
133}
134
135/**
136 * tb_switch_next_cap() - Return next capability in the linked list
137 * @sw: Switch to find the capability for
138 * @offset: Previous capability offset (%0 for start)
139 *
140 * Finds dword offset of the next capability in router config space
141 * capability list and returns it. Passing %0 returns the first entry in
142 * the capability list. If no next capability is found returns %0. In case
143 * of failure returns negative errno.
144 */
145int tb_switch_next_cap(struct tb_switch *sw, unsigned int offset)
146{
147 struct tb_cap_any header;
148 int ret;
149
150 if (!offset)
151 return sw->config.first_cap_offset;
152
153 ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
154 if (ret)
155 return ret;
156
157 switch (header.basic.cap) {
158 case TB_SWITCH_CAP_TMU:
159 ret = header.basic.next;
160 break;
161
162 case TB_SWITCH_CAP_VSE:
163 if (!header.extended_short.length)
164 ret = header.extended_long.next;
165 else
166 ret = header.extended_short.next;
167 break;
168
169 default:
170 tb_sw_dbg(sw, "unknown capability %#x at %#x\n",
171 header.basic.cap, offset);
172 ret = -EINVAL;
173 break;
174 }
175
176 return ret >= VSE_CAP_OFFSET_MAX ? 0 : ret;
177}
178
179/**
180 * tb_switch_find_cap() - Find switch capability
181 * @sw: Switch to find the capability for
182 * @cap: Capability to look
183 *
184 * Returns offset to start of capability or %-ENOENT if no such
185 * capability was found. Negative errno is returned if there was an
186 * error.
187 */
188int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
189{
190 int offset = 0;
191
192 do {
193 struct tb_cap_any header;
194 int ret;
195
196 offset = tb_switch_next_cap(sw, offset);
197 if (offset < 0)
198 return offset;
199
200 ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
201 if (ret)
202 return ret;
203
204 if (header.basic.cap == cap)
205 return offset;
206 } while (offset);
207
208 return -ENOENT;
209}
210
211/**
212 * tb_switch_find_vse_cap() - Find switch vendor specific capability
213 * @sw: Switch to find the capability for
214 * @vsec: Vendor specific capability to look
215 *
216 * Functions enumerates vendor specific capabilities (VSEC) of a switch
217 * and returns offset when capability matching @vsec is found. If no
218 * such capability is found returns %-ENOENT. In case of error returns
219 * negative errno.
220 */
221int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
222{
223 int offset = 0;
224
225 do {
226 struct tb_cap_any header;
227 int ret;
228
229 offset = tb_switch_next_cap(sw, offset);
230 if (offset < 0)
231 return offset;
232
233 ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
234 if (ret)
235 return ret;
236
237 if (header.extended_short.cap == TB_SWITCH_CAP_VSE &&
238 header.extended_short.vsec_id == vsec)
239 return offset;
240 } while (offset);
241
242 return -ENOENT;
243}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Thunderbolt Cactus Ridge driver - capabilities lookup
4 *
5 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
6 */
7
8#include <linux/slab.h>
9#include <linux/errno.h>
10
11#include "tb.h"
12
13#define CAP_OFFSET_MAX 0xff
14#define VSE_CAP_OFFSET_MAX 0xffff
15
16struct tb_cap_any {
17 union {
18 struct tb_cap_basic basic;
19 struct tb_cap_extended_short extended_short;
20 struct tb_cap_extended_long extended_long;
21 };
22} __packed;
23
24/**
25 * tb_port_find_cap() - Find port capability
26 * @port: Port to find the capability for
27 * @cap: Capability to look
28 *
29 * Returns offset to start of capability or %-ENOENT if no such
30 * capability was found. Negative errno is returned if there was an
31 * error.
32 */
33int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
34{
35 u32 offset;
36
37 /*
38 * DP out adapters claim to implement TMU capability but in
39 * reality they do not so we hard code the adapter specific
40 * capability offset here.
41 */
42 if (port->config.type == TB_TYPE_DP_HDMI_OUT)
43 offset = 0x39;
44 else
45 offset = 0x1;
46
47 do {
48 struct tb_cap_any header;
49 int ret;
50
51 ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
52 if (ret)
53 return ret;
54
55 if (header.basic.cap == cap)
56 return offset;
57
58 offset = header.basic.next;
59 } while (offset);
60
61 return -ENOENT;
62}
63
64static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
65{
66 int offset = sw->config.first_cap_offset;
67
68 while (offset > 0 && offset < CAP_OFFSET_MAX) {
69 struct tb_cap_any header;
70 int ret;
71
72 ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
73 if (ret)
74 return ret;
75
76 if (header.basic.cap == cap)
77 return offset;
78
79 offset = header.basic.next;
80 }
81
82 return -ENOENT;
83}
84
85/**
86 * tb_switch_find_vse_cap() - Find switch vendor specific capability
87 * @sw: Switch to find the capability for
88 * @vsec: Vendor specific capability to look
89 *
90 * Functions enumerates vendor specific capabilities (VSEC) of a switch
91 * and returns offset when capability matching @vsec is found. If no
92 * such capability is found returns %-ENOENT. In case of error returns
93 * negative errno.
94 */
95int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
96{
97 struct tb_cap_any header;
98 int offset;
99
100 offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
101 if (offset < 0)
102 return offset;
103
104 while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
105 int ret;
106
107 ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
108 if (ret)
109 return ret;
110
111 /*
112 * Extended vendor specific capabilities come in two
113 * flavors: short and long. The latter is used when
114 * offset is over 0xff.
115 */
116 if (offset >= CAP_OFFSET_MAX) {
117 if (header.extended_long.vsec_id == vsec)
118 return offset;
119 offset = header.extended_long.next;
120 } else {
121 if (header.extended_short.vsec_id == vsec)
122 return offset;
123 if (!header.extended_short.length)
124 return -ENOENT;
125 offset = header.extended_short.next;
126 }
127 }
128
129 return -ENOENT;
130}