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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e2b8785e AN |
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 | ||
da2da04b MW |
13 | #define CAP_OFFSET_MAX 0xff |
14 | #define VSE_CAP_OFFSET_MAX 0xffff | |
e2b8785e AN |
15 | |
16 | struct 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 | ||
da2da04b MW |
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 | */ | |
33 | int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap) | |
e2b8785e | 34 | { |
da2da04b | 35 | u32 offset; |
e2b8785e | 36 | |
da2da04b MW |
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; | |
e2b8785e | 44 | else |
da2da04b MW |
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; | |
e2b8785e AN |
62 | } |
63 | ||
da2da04b | 64 | static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap) |
e2b8785e | 65 | { |
da2da04b MW |
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; | |
e2b8785e | 80 | } |
da2da04b MW |
81 | |
82 | return -ENOENT; | |
e2b8785e AN |
83 | } |
84 | ||
85 | /** | |
da2da04b MW |
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 | |
e2b8785e | 89 | * |
da2da04b MW |
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. | |
e2b8785e | 94 | */ |
da2da04b | 95 | int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec) |
e2b8785e | 96 | { |
e2b8785e | 97 | struct tb_cap_any header; |
da2da04b MW |
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) | |
e2b8785e | 118 | return offset; |
da2da04b MW |
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; | |
e2b8785e | 126 | } |
e2b8785e | 127 | } |
da2da04b MW |
128 | |
129 | return -ENOENT; | |
e2b8785e | 130 | } |