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Message-Id: <1385688949-7101-9-git-send-email-andreas.noever@gmail.com>
Date: Fri, 29 Nov 2013 02:35:45 +0100
From: Andreas Noever <andreas.noever@...il.com>
To: linux-kernel@...r.kernel.org
Cc: Andreas Noever <andreas.noever@...il.com>
Subject: [PATCH 08/12] thunderbolt: Scan for downstream switches
Add utility methods tb_port_state and tb_wait_for_port. Add tb_scan_port
which checks whether a port is connected and if so allocates a
downstream switch.
Signed-off-by: Andreas Noever <andreas.noever@...il.com>
---
drivers/thunderbolt/tb.c | 160 +++++++++++++++++++++++++++++++++++++++++++++++
drivers/thunderbolt/tb.h | 17 +++++
2 files changed, 177 insertions(+)
diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 3837f1a..9daff7b 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -84,6 +84,25 @@ static void tb_dump_port(struct tb *tb, struct tb_regs_port_header *port)
port->nfc_credits);
}
+
+/**
+ * tb_downstream_route() - get route to downstream switch
+ *
+ * Port must not be the upstream port (otherwise a loop is created).
+ *
+ * Return: Returns a route to the switch behind @port.
+ */
+static u64 tb_downstream_route(struct tb_port *port)
+{
+ return tb_route(port->sw)
+ | ((u64) port->port << (port->sw->config.depth * 8));
+}
+
+static bool tb_is_upstream_port(struct tb_port *port)
+{
+ return port == tb_upstream_port(port->sw);
+}
+
static int tb_route_length(u64 route)
{
return (fls64(route) + TB_ROUTE_SHIFT - 1) / TB_ROUTE_SHIFT;
@@ -192,6 +211,84 @@ int tb_find_cap(struct tb_port *port, enum tb_cfg_space space, enum tb_cap cap)
return -EIO;
}
+/* thunderbolt port utility functions */
+
+/**
+ * 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 a tb_port_state on success or an error code on failure.
+ */
+static enum tb_port_state 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
+ *
+ * Check if the port is connected but not up. If so we wait for some
+ * time to see whether it comes up.
+ *
+ * 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.
+ */
+static int tb_wait_for_port(struct tb_port *port)
+{
+ int retries = 10;
+ enum tb_port_state 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) {
+ 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;
+}
+
/* thunderbolt switch utility functions */
@@ -240,13 +337,25 @@ static int tb_plug_events_active(struct tb_switch *sw, bool active)
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;
+ port->remote = NULL;
res = tb_port_read(port, &port->config, TB_CFG_PORT, 0, 8);
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. */
@@ -259,6 +368,14 @@ static int tb_init_port(struct tb_switch *sw, u8 port_nr)
*/
static void tb_switch_free(struct tb_switch *sw)
{
+ int i;
+ /* port 0 is the switch itself and never has a remote */
+ for (i = 1; i <= sw->config.max_port_number; i++) {
+ if (tb_is_upstream_port(&sw->ports[i]))
+ continue;
+ if (sw->ports[i].remote)
+ tb_switch_free(sw->ports[i].remote->sw);
+ }
kfree(sw->ports);
kfree(sw);
}
@@ -349,6 +466,9 @@ err:
return NULL;
}
+
+/* startup, enumeration, hot plug handling and shutdown */
+
/**
* reset_switch() - send TB_CFG_PKG_RESET and enable switch
*
@@ -369,6 +489,44 @@ static int tb_switch_reset(struct tb *tb, u64 route)
return tb_cfg_write(tb->cfg, ((u32 *) &header) + 2, route, 0, 2, 2, 2);
}
+static void tb_link_ports(struct tb_port *down, struct tb_port *up)
+{
+ down->remote = up;
+ up->remote = down;
+}
+
+static void tb_scan_port(struct tb_port *port);
+
+static void tb_scan_ports(struct tb_switch *sw)
+{
+ int i;
+ for (i = 1; i <= sw->config.max_port_number; i++)
+ tb_scan_port(&sw->ports[i]);
+}
+
+/**
+ * tb_scan_port() - check for switches below port
+ *
+ * Checks whether port is connected. If so then we try to create a downstream
+ * switch and recursively scan its ports
+ */
+static void tb_scan_port(struct tb_port *port)
+{
+ struct tb_switch *sw;
+ if (tb_is_upstream_port(port))
+ return;
+ if (port->config.type != TB_TYPE_PORT)
+ return;
+ if (tb_wait_for_port(port) <= 0)
+ return;
+
+ sw = tb_switch_alloc(port->sw->tb, tb_downstream_route(port));
+ if (!sw)
+ return;
+ tb_link_ports(port, tb_upstream_port(sw));
+ tb_scan_ports(sw);
+}
+
struct tb_hotplug_event {
struct work_struct work;
struct tb *tb;
@@ -487,6 +645,8 @@ struct tb *thunderbolt_alloc_and_start(struct tb_nhi *nhi)
if (!tb->root_switch)
goto err_locked;
+ tb_scan_ports(tb->root_switch);
+
mutex_unlock(&tb->lock);
return tb;
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 2ada42a..fe35d4d 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -32,6 +32,8 @@ struct tb_switch {
struct tb_port {
struct tb_regs_port_header config;
struct tb_switch *sw;
+ struct tb_port *remote; /* remote port, NULL if not connected */
+ int cap_phy; /* offset, zero if not found */
u8 port; /* port number on switch */
bool invalid; /* unplugged, will go away */
};
@@ -54,6 +56,21 @@ struct tb {
*/
};
+/**
+ * tb_upstream_port() - return the upstream port of a switch
+ *
+ * Every switch has an upstream port (for the root switch it is the NHI).
+ *
+ * During switch alloc/init tb_upstream_port()->remote may be NULL, even for
+ * non root switches (on the NHI port remote is always NULL).
+ *
+ * Return: Returns the upstream port of the switch.
+ */
+static inline struct tb_port *tb_upstream_port(struct tb_switch *sw)
+{
+ return &sw->ports[sw->config.upstream_port_number];
+}
+
static inline u64 tb_route(struct tb_switch *sw)
{
return ((u64) sw->config.route_hi) << 32 | sw->config.route_lo;
--
1.8.4.2
--
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