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thunderbolt: Add Display Port CM handshake for Titan Ridge devices

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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 <mika.westerberg@linux.intel.com>
This commit is contained in:
Mika Westerberg 2019-02-15 18:18:47 +02:00
parent 7bffd97eb7
commit de718ac7b6
2 changed files with 48 additions and 0 deletions
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3
drivers/thunderbolt/tb_regs.h
View file

@ -252,6 +252,9 @@ struct tb_regs_port_header {
#define ADP_DP_CS_3_HDPC BIT(9)
#define DP_LOCAL_CAP 0x04
#define DP_REMOTE_CAP 0x05
#define DP_STATUS_CTRL 0x06
#define DP_STATUS_CTRL_CMHS BIT(25)
#define DP_STATUS_CTRL_UF BIT(26)
/* PCIe adapter registers */
#define ADP_PCIE_CS_0 0x00

45
drivers/thunderbolt/tunnel.c
View file

@ -6,6 +6,7 @@
* Copyright (C) 2019, Intel Corporation
*/
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/list.h>
@ -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);