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thunderbolt: Scan for downstream switches

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Add utility methods tb_port_state and tb_wait_for_port. Add
tb_scan_switch which recursively checks for downstream switches.

Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andreas Noever
2014-06-03 22:04:05 +02:00
committed by Greg Kroah-Hartman
parent ca389f716f
commit 9da672a428
3 changed files with 157 additions and 0 deletions
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97
drivers/thunderbolt/switch.c
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@@ -52,6 +52,92 @@ static void tb_dump_port(struct tb *tb, struct tb_regs_port_header *port)
tb_info(tb, " NFC Credits: %#x\n", port->nfc_credits);
}
/**
* tb_port_state() - get connectedness state of a port
*
* The port must have a TB_CAP_PHY (i.e. it should be a real port).
*
* Return: Returns an enum tb_port_state on success or an error code on failure.
*/
static int tb_port_state(struct tb_port *port)
{
struct tb_cap_phy phy;
int res;
if (port->cap_phy == 0) {
tb_port_WARN(port, "does not have a PHY\n");
return -EINVAL;
}
res = tb_port_read(port, &phy, TB_CFG_PORT, port->cap_phy, 2);
if (res)
return res;
return phy.state;
}
/**
* tb_wait_for_port() - wait for a port to become ready
*
* Wait up to 1 second for a port to reach state TB_PORT_UP. If
* wait_if_unplugged is set then we also wait if the port is in state
* TB_PORT_UNPLUGGED (it takes a while for the device to be registered after
* switch resume). Otherwise we only wait if a device is registered but the link
* has not yet been established.
*
* Return: Returns an error code on failure. Returns 0 if the port is not
* connected or failed to reach state TB_PORT_UP within one second. Returns 1
* if the port is connected and in state TB_PORT_UP.
*/
int tb_wait_for_port(struct tb_port *port, bool wait_if_unplugged)
{
int retries = 10;
int state;
if (!port->cap_phy) {
tb_port_WARN(port, "does not have PHY\n");
return -EINVAL;
}
if (tb_is_upstream_port(port)) {
tb_port_WARN(port, "is the upstream port\n");
return -EINVAL;
}
while (retries--) {
state = tb_port_state(port);
if (state < 0)
return state;
if (state == TB_PORT_DISABLED) {
tb_port_info(port, "is disabled (state: 0)\n");
return 0;
}
if (state == TB_PORT_UNPLUGGED) {
if (wait_if_unplugged) {
/* used during resume */
tb_port_info(port,
"is unplugged (state: 7), retrying...\n");
msleep(100);
continue;
}
tb_port_info(port, "is unplugged (state: 7)\n");
return 0;
}
if (state == TB_PORT_UP) {
tb_port_info(port,
"is connected, link is up (state: 2)\n");
return 1;
}
/*
* After plug-in the state is TB_PORT_CONNECTING. Give it some
* time.
*/
tb_port_info(port,
"is connected, link is not up (state: %d), retrying...\n",
state);
msleep(100);
}
tb_port_warn(port,
"failed to reach state TB_PORT_UP. Ignoring port...\n");
return 0;
}
/**
* tb_init_port() - initialize a port
*
@@ -63,6 +149,7 @@ static void tb_dump_port(struct tb *tb, struct tb_regs_port_header *port)
static int tb_init_port(struct tb_switch *sw, u8 port_nr)
{
int res;
int cap;
struct tb_port *port = &sw->ports[port_nr];
port->sw = sw;
port->port = port_nr;
@@ -71,6 +158,16 @@ static int tb_init_port(struct tb_switch *sw, u8 port_nr)
if (res)
return res;
/* Port 0 is the switch itself and has no PHY. */
if (port->config.type == TB_TYPE_PORT && port_nr != 0) {
cap = tb_find_cap(port, TB_CFG_PORT, TB_CAP_PHY);
if (cap > 0)
port->cap_phy = cap;
else
tb_port_WARN(port, "non switch port without a PHY\n");
}
tb_dump_port(sw->tb, &port->config);
/* TODO: Read dual link port, DP port and more from EEPROM. */