diff options
Diffstat (limited to 'drivers/thunderbolt/switch.c')
| -rw-r--r-- | drivers/thunderbolt/switch.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/drivers/thunderbolt/switch.c b/drivers/thunderbolt/switch.c index 6f98b3d6eb2a..ecd41f7b7649 100644 --- a/drivers/thunderbolt/switch.c +++ b/drivers/thunderbolt/switch.c @@ -677,6 +677,60 @@ void tb_port_release_out_hopid(struct tb_port *port, int hopid) } /** + * tb_next_port_on_path() - Return next port for given port on a path + * @start: Start port of the walk + * @end: End port of the walk + * @prev: Previous port (%NULL if this is the first) + * + * This function can be used to walk from one port to another if they + * are connected through zero or more switches. If the @prev is dual + * link port, the function follows that link and returns another end on + * that same link. + * + * If the @end port has been reached, return %NULL. + * + * Domain tb->lock must be held when this function is called. + */ +struct tb_port *tb_next_port_on_path(struct tb_port *start, struct tb_port *end, + struct tb_port *prev) +{ + struct tb_port *next; + + if (!prev) + return start; + + if (prev->sw == end->sw) { + if (prev == end) + return NULL; + return end; + } + + if (start->sw->config.depth < end->sw->config.depth) { + if (prev->remote && + prev->remote->sw->config.depth > prev->sw->config.depth) + next = prev->remote; + else + next = tb_port_at(tb_route(end->sw), prev->sw); + } else { + if (tb_is_upstream_port(prev)) { + next = prev->remote; + } else { + next = tb_upstream_port(prev->sw); + /* + * Keep the same link if prev and next are both + * dual link ports. + */ + if (next->dual_link_port && + next->link_nr != prev->link_nr) { + next = next->dual_link_port; + } + } + } + + return next; +} + +/** * tb_pci_port_enable() - Enable PCIe adapter port * @port: PCIe port to enable * @enable: Enable/disable the PCIe adapter |