[PATCH 3/3] thunderbolt: Disable LTTPR on Intel Titan Ridge

[Mika Westerberg <mika.westerberg@linux.intel.com>]

Intel Titan Ridge does not disable AUX timers when it gets SET_CONFIG
with SET_LTTPR_MODE set which makes DP tunneling to fail. For this
reason disable LTTPR on Titan Ridge device side.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/thunderbolt/tb_regs.h |  1 +
 drivers/thunderbolt/tunnel.c  | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/drivers/thunderbolt/tb_regs.h b/drivers/thunderbolt/tb_regs.h
index dc00cbd69d36..70795a2aa9bb 100644
--- a/drivers/thunderbolt/tb_regs.h
+++ b/drivers/thunderbolt/tb_regs.h
@@ -389,6 +389,7 @@ struct tb_regs_port_header {
 #define DP_COMMON_CAP_1_LANE			0x0
 #define DP_COMMON_CAP_2_LANES			0x1
 #define DP_COMMON_CAP_4_LANES			0x2
+#define DP_COMMON_CAP_LTTPR_NS			BIT(27)
 #define DP_COMMON_CAP_DPRX_DONE			BIT(31)
 
 /* PCIe adapter registers */
diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index a473cc7d9a8d..118742ec93ed 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -580,6 +580,16 @@ static int tb_dp_xchg_caps(struct tb_tunnel *tunnel)
 		out_dp_cap = tb_dp_cap_set_lanes(out_dp_cap, new_lanes);
 	}
 
+	/*
+	 * Titan Ridge does not disable AUX timers when it gets
+	 * SET_CONFIG with SET_LTTPR_MODE set. This causes problems with
+	 * DP tunneling.
+	 */
+	if (tb_route(out->sw) && tb_switch_is_titan_ridge(out->sw)) {
+		out_dp_cap |= DP_COMMON_CAP_LTTPR_NS;
+		tb_port_dbg(out, "disabling LTTPR\n");
+	}
+
 	return tb_port_write(in, &out_dp_cap, TB_CFG_PORT,
 			     in->cap_adap + DP_REMOTE_CAP, 1);
 }
-- 
2.34.1