From de718ac7b6aefa594d5d95881882bc68ec3b83b6 Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Fri, 15 Feb 2019 18:18:47 +0200 Subject: thunderbolt: Add Display Port CM handshake for Titan Ridge devices Titan Ridge needs an additional connection manager handshake in order to do proper Display Port tunneling so implement it here. Signed-off-by: Mika Westerberg --- drivers/thunderbolt/tunnel.c | 45 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) (limited to 'drivers/thunderbolt/tunnel.c') diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c index 3353396e0806..009c2683a386 100644 --- a/drivers/thunderbolt/tunnel.c +++ b/drivers/thunderbolt/tunnel.c @@ -6,6 +6,7 @@ * Copyright (C) 2019, Intel Corporation */ +#include #include #include @@ -242,6 +243,42 @@ struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up, return tunnel; } +static int tb_dp_cm_handshake(struct tb_port *in, struct tb_port *out) +{ + int timeout = 10; + u32 val; + int ret; + + /* Both ends need to support this */ + if (!tb_switch_is_titan_ridge(in->sw) || + !tb_switch_is_titan_ridge(out->sw)) + return 0; + + ret = tb_port_read(out, &val, TB_CFG_PORT, + out->cap_adap + DP_STATUS_CTRL, 1); + if (ret) + return ret; + + val |= DP_STATUS_CTRL_UF | DP_STATUS_CTRL_CMHS; + + ret = tb_port_write(out, &val, TB_CFG_PORT, + out->cap_adap + DP_STATUS_CTRL, 1); + if (ret) + return ret; + + do { + ret = tb_port_read(out, &val, TB_CFG_PORT, + out->cap_adap + DP_STATUS_CTRL, 1); + if (ret) + return ret; + if (!(val & DP_STATUS_CTRL_CMHS)) + return 0; + usleep_range(10, 100); + } while (timeout--); + + return -ETIMEDOUT; +} + static int tb_dp_xchg_caps(struct tb_tunnel *tunnel) { struct tb_port *out = tunnel->dst_port; @@ -256,6 +293,14 @@ static int tb_dp_xchg_caps(struct tb_tunnel *tunnel) if (in->sw->generation < 2 || out->sw->generation < 2) return 0; + /* + * Perform connection manager handshake between IN and OUT ports + * before capabilities exchange can take place. + */ + ret = tb_dp_cm_handshake(in, out); + if (ret) + return ret; + /* Read both DP_LOCAL_CAP registers */ ret = tb_port_read(in, &in_dp_cap, TB_CFG_PORT, in->cap_adap + DP_LOCAL_CAP, 1); -- cgit v1.2.3-59-g8ed1b