diff options
Diffstat (limited to 'drivers/thunderbolt')
| -rw-r--r-- | drivers/thunderbolt/cap.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/drivers/thunderbolt/cap.c b/drivers/thunderbolt/cap.c index a58585b4e6d9..8bf8e031f0bc 100644 --- a/drivers/thunderbolt/cap.c +++ b/drivers/thunderbolt/cap.c @@ -52,6 +52,21 @@ static int tb_port_enable_tmu(struct tb_port *port, bool enable) return tb_sw_write(sw, &value, TB_CFG_SWITCH, offset, 1); } +static void tb_port_dummy_read(struct tb_port *port) +{ + /* + * When reading from next capability pointer location in port + * config space the read data is not cleared on LR. To avoid + * reading stale data on next read perform one dummy read after + * port capabilities are walked. + */ + if (tb_switch_is_lr(port->sw)) { + u32 dummy; + + tb_port_read(port, &dummy, TB_CFG_PORT, 0, 1); + } +} + static int __tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap) { u32 offset = 1; @@ -92,6 +107,7 @@ int tb_port_find_cap(struct tb_port *port, enum tb_port_cap cap) ret = __tb_port_find_cap(port, cap); + tb_port_dummy_read(port); tb_port_enable_tmu(port, false); return ret; |