linux/drivers/thunderbolt/cap.c
Mika Westerberg da2da04b8d thunderbolt: Rework capability handling
Organization of the capabilities in switches and ports is not so random
after all. Rework the capability handling functionality so that it
follows how capabilities are organized and provide two new functions
(tb_switch_find_vse_cap() and tb_port_find_cap()) which can be used to
extract capabilities for ports and switches. Then convert the current
users over these.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-06-09 11:42:41 +02:00

130 lines
2.9 KiB
C

/*
* Thunderbolt Cactus Ridge driver - capabilities lookup
*
* Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
*/
#include <linux/slab.h>
#include <linux/errno.h>
#include "tb.h"
#define CAP_OFFSET_MAX 0xff
#define VSE_CAP_OFFSET_MAX 0xffff
struct tb_cap_any {
union {
struct tb_cap_basic basic;
struct tb_cap_extended_short extended_short;
struct tb_cap_extended_long extended_long;
};
} __packed;
/**
* tb_port_find_cap() - Find port capability
* @port: Port to find the capability for
* @cap: Capability to look
*
* Returns offset to start of capability or %-ENOENT if no such
* capability was found. Negative errno is returned if there was an
* error.
*/
int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap)
{
u32 offset;
/*
* DP out adapters claim to implement TMU capability but in
* reality they do not so we hard code the adapter specific
* capability offset here.
*/
if (port->config.type == TB_TYPE_DP_HDMI_OUT)
offset = 0x39;
else
offset = 0x1;
do {
struct tb_cap_any header;
int ret;
ret = tb_port_read(port, &header, TB_CFG_PORT, offset, 1);
if (ret)
return ret;
if (header.basic.cap == cap)
return offset;
offset = header.basic.next;
} while (offset);
return -ENOENT;
}
static int tb_switch_find_cap(struct tb_switch *sw, enum tb_switch_cap cap)
{
int offset = sw->config.first_cap_offset;
while (offset > 0 && offset < CAP_OFFSET_MAX) {
struct tb_cap_any header;
int ret;
ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 1);
if (ret)
return ret;
if (header.basic.cap == cap)
return offset;
offset = header.basic.next;
}
return -ENOENT;
}
/**
* tb_switch_find_vse_cap() - Find switch vendor specific capability
* @sw: Switch to find the capability for
* @vsec: Vendor specific capability to look
*
* Functions enumerates vendor specific capabilities (VSEC) of a switch
* and returns offset when capability matching @vsec is found. If no
* such capability is found returns %-ENOENT. In case of error returns
* negative errno.
*/
int tb_switch_find_vse_cap(struct tb_switch *sw, enum tb_switch_vse_cap vsec)
{
struct tb_cap_any header;
int offset;
offset = tb_switch_find_cap(sw, TB_SWITCH_CAP_VSE);
if (offset < 0)
return offset;
while (offset > 0 && offset < VSE_CAP_OFFSET_MAX) {
int ret;
ret = tb_sw_read(sw, &header, TB_CFG_SWITCH, offset, 2);
if (ret)
return ret;
/*
* Extended vendor specific capabilities come in two
* flavors: short and long. The latter is used when
* offset is over 0xff.
*/
if (offset >= CAP_OFFSET_MAX) {
if (header.extended_long.vsec_id == vsec)
return offset;
offset = header.extended_long.next;
} else {
if (header.extended_short.vsec_id == vsec)
return offset;
if (!header.extended_short.length)
return -ENOENT;
offset = header.extended_short.next;
}
}
return -ENOENT;
}