2 * Thunderbolt Cactus Ridge driver - capabilities lookup
4 * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
7 #include <linux/slab.h>
8 #include <linux/errno.h>
12 #define CAP_OFFSET_MAX 0xff
13 #define VSE_CAP_OFFSET_MAX 0xffff
17 struct tb_cap_basic basic;
18 struct tb_cap_extended_short extended_short;
19 struct tb_cap_extended_long extended_long;
24 * tb_port_find_cap() - Find port capability
25 * @port: Port to find the capability for
26 * @cap: Capability to look
28 * Returns offset to start of capability or %-ENOENT if no such
29 * capability was found. Negative errno is returned if there was an
32 int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
37 * DP out adapters claim to implement TMU capability but in
38 * reality they do not so we hard code the adapter specific
39 * capability offset here.
41 if (port->config.type == TB_TYPE_DP_HDMI_OUT)
47 struct tb_cap_any header;
50 ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
54 if (header.basic.cap == cap)
57 offset = header.basic.next;
63 static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
65 int offset = sw->config.first_cap_offset;
67 while (offset > 0 && offset < CAP_OFFSET_MAX) {
68 struct tb_cap_any header;
71 ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
75 if (header.basic.cap == cap)
78 offset = header.basic.next;
85 * tb_switch_find_vse_cap() - Find switch vendor specific capability
86 * @sw: Switch to find the capability for
87 * @vsec: Vendor specific capability to look
89 * Functions enumerates vendor specific capabilities (VSEC) of a switch
90 * and returns offset when capability matching @vsec is found. If no
91 * such capability is found returns %-ENOENT. In case of error returns
94 int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
96 struct tb_cap_any header;
99 offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
103 while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
106 ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
111 * Extended vendor specific capabilities come in two
112 * flavors: short and long. The latter is used when
113 * offset is over 0xff.
115 if (offset >= CAP_OFFSET_MAX) {
116 if (header.extended_long.vsec_id == vsec)
118 offset = header.extended_long.next;
120 if (header.extended_short.vsec_id == vsec)
122 if (!header.extended_short.length)
124 offset = header.extended_short.next;