Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e2b8785e | 2 | /* |
15c6784c | 3 | * Thunderbolt driver - capabilities lookup |
e2b8785e AN |
4 | * |
5 | * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com> | |
15c6784c | 6 | * Copyright (C) 2018, Intel Corporation |
e2b8785e AN |
7 | */ |
8 | ||
9 | #include <linux/slab.h> | |
10 | #include <linux/errno.h> | |
11 | ||
12 | #include "tb.h" | |
13 | ||
da2da04b MW |
14 | #define CAP_OFFSET_MAX 0xff |
15 | #define VSE_CAP_OFFSET_MAX 0xffff | |
e2b8785e AN |
16 | |
17 | struct tb_cap_any { | |
18 | union { | |
19 | struct tb_cap_basic basic; | |
20 | struct tb_cap_extended_short extended_short; | |
21 | struct tb_cap_extended_long extended_long; | |
22 | }; | |
23 | } __packed; | |
24 | ||
da2da04b MW |
25 | /** |
26 | * tb_port_find_cap() - Find port capability | |
27 | * @port: Port to find the capability for | |
28 | * @cap: Capability to look | |
29 | * | |
30 | * Returns offset to start of capability or %-ENOENT if no such | |
31 | * capability was found. Negative errno is returned if there was an | |
32 | * error. | |
33 | */ | |
34 | int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap) | |
e2b8785e | 35 | { |
da2da04b | 36 | u32 offset; |
e2b8785e | 37 | |
da2da04b MW |
38 | /* |
39 | * DP out adapters claim to implement TMU capability but in | |
40 | * reality they do not so we hard code the adapter specific | |
41 | * capability offset here. | |
42 | */ | |
43 | if (port->config.type == TB_TYPE_DP_HDMI_OUT) | |
44 | offset = 0x39; | |
e2b8785e | 45 | else |
da2da04b MW |
46 | offset = 0x1; |
47 | ||
48 | do { | |
49 | struct tb_cap_any header; | |
50 | int ret; | |
51 | ||
52 | ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1); | |
53 | if (ret) | |
54 | return ret; | |
55 | ||
56 | if (header.basic.cap == cap) | |
57 | return offset; | |
58 | ||
59 | offset = header.basic.next; | |
60 | } while (offset); | |
61 | ||
62 | return -ENOENT; | |
e2b8785e AN |
63 | } |
64 | ||
da2da04b | 65 | static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap) |
e2b8785e | 66 | { |
da2da04b MW |
67 | int offset = sw->config.first_cap_offset; |
68 | ||
69 | while (offset > 0 && offset < CAP_OFFSET_MAX) { | |
70 | struct tb_cap_any header; | |
71 | int ret; | |
72 | ||
73 | ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1); | |
74 | if (ret) | |
75 | return ret; | |
76 | ||
77 | if (header.basic.cap == cap) | |
78 | return offset; | |
79 | ||
80 | offset = header.basic.next; | |
e2b8785e | 81 | } |
da2da04b MW |
82 | |
83 | return -ENOENT; | |
e2b8785e AN |
84 | } |
85 | ||
86 | /** | |
da2da04b MW |
87 | * tb_switch_find_vse_cap() - Find switch vendor specific capability |
88 | * @sw: Switch to find the capability for | |
89 | * @vsec: Vendor specific capability to look | |
e2b8785e | 90 | * |
da2da04b MW |
91 | * Functions enumerates vendor specific capabilities (VSEC) of a switch |
92 | * and returns offset when capability matching @vsec is found. If no | |
93 | * such capability is found returns %-ENOENT. In case of error returns | |
94 | * negative errno. | |
e2b8785e | 95 | */ |
da2da04b | 96 | int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec) |
e2b8785e | 97 | { |
e2b8785e | 98 | struct tb_cap_any header; |
da2da04b MW |
99 | int offset; |
100 | ||
101 | offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE); | |
102 | if (offset < 0) | |
103 | return offset; | |
104 | ||
105 | while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) { | |
106 | int ret; | |
107 | ||
108 | ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2); | |
109 | if (ret) | |
110 | return ret; | |
111 | ||
112 | /* | |
113 | * Extended vendor specific capabilities come in two | |
114 | * flavors: short and long. The latter is used when | |
115 | * offset is over 0xff. | |
116 | */ | |
117 | if (offset >= CAP_OFFSET_MAX) { | |
118 | if (header.extended_long.vsec_id == vsec) | |
e2b8785e | 119 | return offset; |
da2da04b MW |
120 | offset = header.extended_long.next; |
121 | } else { | |
122 | if (header.extended_short.vsec_id == vsec) | |
123 | return offset; | |
124 | if (!header.extended_short.length) | |
125 | return -ENOENT; | |
126 | offset = header.extended_short.next; | |
e2b8785e | 127 | } |
e2b8785e | 128 | } |
da2da04b MW |
129 | |
130 | return -ENOENT; | |
e2b8785e | 131 | } |