[PATCH v4 10/36] thunderbolt: Configure lanes when switch is initialized

Mika Westerberg
2019-04-10T13:42:25Z

Thunderbolt 2 devices and beyond need to have additional bits set in
link controller specific registers. This includes two bits in LC_SX_CTRL
that tell the link controller which lane is connected and whether it is
upstream facing or not.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
drivers/thunderbolt/lc.c | 114 ++++++++++++++++++++++++++++++++++
drivers/thunderbolt/switch.c | 9 +++
drivers/thunderbolt/tb.h | 2 +
drivers/thunderbolt/tb_regs.h | 11 ++++
4 files changed, 136 insertions(+)

diff --git a/drivers/thunderbolt/lc.c b/drivers/thunderbolt/lc.c
index 2134a55ed837..a5dddf176546 100644
--- a/drivers/thunderbolt/lc.c
+++ b/drivers/thunderbolt/lc.c
@@ -19,3 +19,117 @@ int tb_lc_read_uuid(struct tb_switch *sw, u32 *uuid)
return -EINVAL;
return tb_sw_read(sw, uuid, TB_CFG_SWITCH, sw->cap_lc + TB_LC_FUSE, 4);
}
+
+static int read_lc_desc(struct tb_switch *sw, u32 *desc)
+{
+ if (!sw->cap_lc)
+ return -EINVAL;
+ return tb_sw_read(sw, desc, TB_CFG_SWITCH, sw->cap_lc + TB_LC_DESC, 1);
+}
+
+static int find_port_lc_cap(struct tb_port *port)
+{
+ struct tb_switch *sw = port->sw;
+ int start, phys, ret, size;
+ u32 desc;
+
+ ret = read_lc_desc(sw, &desc);
+ if (ret)
+ return ret;
+
+ /* Start of port LC registers */
+ start = (desc & TB_LC_DESC_SIZE_MASK) >> TB_LC_DESC_SIZE_SHIFT;
+ size = (desc & TB_LC_DESC_PORT_SIZE_MASK) >> TB_LC_DESC_PORT_SIZE_SHIFT;
+ phys = tb_phy_port_from_link(port->port);
+
+ return sw->cap_lc + start + phys * size;
+}
+
+static int tb_lc_configure_lane(struct tb_port *port, bool configure)
+{
+ bool upstream = tb_is_upstream_port(port);
+ struct tb_switch *sw = port->sw;
+ u32 ctrl, lane;
+ int cap, ret;
+
+ if (sw->generation < 2)
+ return 0;
+
+ cap = find_port_lc_cap(port);
+ if (cap < 0)
+ return cap;
+
+ ret = tb_sw_read(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
+ if (ret)
+ return ret;
+
+ /* Resolve correct lane */
+ if (port->port % 2)
+ lane = TB_LC_SX_CTRL_L1C;
+ else
+ lane = TB_LC_SX_CTRL_L2C;
+
+ if (configure) {
+ ctrl |= lane;
+ if (upstream)
+ ctrl |= TB_LC_SX_CTRL_UPSTREAM;
+ } else {
+ ctrl &= ~lane;
+ if (upstream)
+ ctrl &= ~TB_LC_SX_CTRL_UPSTREAM;
+ }
+
+ return tb_sw_write(sw, &ctrl, TB_CFG_SWITCH, cap + TB_LC_SX_CTRL, 1);
+}
+
+/**
+ * tb_lc_configure_link() - Let LC know about configured link
+ * @sw: Switch that is being added
+ *
+ * Informs LC of both parent switch and @sw that there is established
+ * link between the two.
+ */
+int tb_lc_configure_link(struct tb_switch *sw)
+{
+ struct tb_port *up, *down;
+ int ret;
+
+ if (!sw->config.enabled || !tb_route(sw))
+ return 0;
+
+ up = tb_upstream_port(sw);
+ down = tb_port_at(tb_route(sw), tb_to_switch(sw->dev.parent));
+
+ /* Configure parent link toward this switch */
+ ret = tb_lc_configure_lane(down, true);
+ if (ret)
+ return ret;
+
+ /* Configure upstream link from this switch to the parent */
+ ret = tb_lc_configure_lane(up, true);
+ if (ret)
+ tb_lc_configure_lane(down, false);
+
+ return ret;
+}
+
+/**
+ * tb_lc_unconfigure_link() - Let LC know about unconfigured link
+ * @sw: Switch to unconfigure
+ *
+ * Informs LC of both parent switch and @sw that the link between the
+ * two does not exist anymore.
+ */
+void tb_lc_unconfigure_link(struct tb_switch *sw)
+{
+ struct tb_port *up, *down;
+
+ if (sw->is_unplugged || !sw->config.enabled || !tb_route(sw))
+ return;
+
+ up = tb_upstream_port(sw);
+ down = tb_port_at(tb_route(sw), tb_to_switch(sw->dev.parent));
+
+ tb_lc_configure_lane(up, false);
+ tb_lc_configure_lane(down, false);
+}
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c
index 63ff4c753d89..dd218dc4781b 100644
--- a/drivers/thunderbolt/switch.c
+++ b/drivers/thunderbolt/switch.c
@@ -1276,6 +1276,10 @@ int tb_switch_configure(struct tb_switch *sw)
if (ret)
return ret;

+ ret = tb_lc_configure_link(sw);
+ if (ret)
+ return ret;
+
return tb_plug_events_active(sw, true);
}

@@ -1486,6 +1490,7 @@ void tb_switch_remove(struct tb_switch *sw)

if (!sw->is_unplugged)
tb_plug_events_active(sw, false);
+ tb_lc_unconfigure_link(sw);

tb_switch_nvm_remove(sw);

@@ -1545,6 +1550,10 @@ int tb_switch_resume(struct tb_switch *sw)
if (err)
return err;

+ err = tb_lc_configure_link(sw);
+ if (err)
+ return err;
+
err = tb_plug_events_active(sw, true);
if (err)
return err;
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index e52d39b25266..69e0534224d8 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -465,6 +465,8 @@ int tb_drom_read(struct tb_switch *sw);
int tb_drom_read_uid_only(struct tb_switch *sw, u64 *uid);

int tb_lc_read_uuid(struct tb_switch *sw, u32 *uuid);
+int tb_lc_configure_link(struct tb_switch *sw);
+void tb_lc_unconfigure_link(struct tb_switch *sw);

static inline int tb_route_length(u64 route)
{
diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index 4895ae9f0b40..e0f867dad5cf 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -238,6 +238,17 @@ struct tb_regs_hop {
} __packed;

/* Common link controller registers */
+#define TB_LC_DESC 0x02
+#define TB_LC_DESC_SIZE_SHIFT 8
+#define TB_LC_DESC_SIZE_MASK GENMASK(15, 8)
+#define TB_LC_DESC_PORT_SIZE_SHIFT 16
+#define TB_LC_DESC_PORT_SIZE_MASK GENMASK(27, 16)
#define TB_LC_FUSE 0x03

+/* Link controller registers */
+#define TB_LC_SX_CTRL 0x96
+#define TB_LC_SX_CTRL_L1C BIT(16)
+#define TB_LC_SX_CTRL_L2C BIT(20)
+#define TB_LC_SX_CTRL_UPSTREAM BIT(30)
+
#endif
--
2.20.1