@@ -171,18 +171,30 @@ static const char *drm_dp_mst_sideband_tx_state_str(int state)
return sideband_reason_str[state];
}
+static inline u8
+drm_dp_mst_get_ufp_num_at_lct_from_rad(u8 lct, u8 *rad)
+{
+ int idx = (lct / 2) - 1;
+ int shift = (lct % 2) ? 0 : 4;
+ u8 ufp_num;
+
+ /* mst_primary, it's rad is unset*/
+ if (lct == 1)
+ return 0;
+
+ ufp_num = (rad[idx] >> shift) & 0xf;
+
+ return ufp_num;
+}
+
static int
drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len)
{
int i;
u8 unpacked_rad[16] = {};
- for (i = 1; i < lct; i++) {
- if (i % 2)
- unpacked_rad[i] = rad[(i - 1) / 2] >> 4;
- else
- unpacked_rad[i] = rad[(i - 1) / 2] & 0xF;
- }
+ for (i = 0; i < lct; i++)
+ unpacked_rad[i] = drm_dp_mst_get_ufp_num_at_lct_from_rad(i + 1, rad);
/* TODO: Eventually add something to printk so we can format the rad
* like this: 1.2.3
@@ -2544,9 +2556,9 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_
if (!mstb)
goto out;
- for (i = 0; i < lct - 1; i++) {
- int shift = (i % 2) ? 0 : 4;
- int port_num = (rad[i / 2] >> shift) & 0xf;
+ for (i = 1; i < lct; i++) {
+ int port_num =
+ drm_dp_mst_get_ufp_num_at_lct_from_rad(i + 1, rad);
list_for_each_entry(port, &mstb->ports, next) {
if (port->port_num == port_num) {
Add a helper drm_dp_mst_get_ufp_num_at_lct_from_rad() to extract the up facing port number at specific link count from the RAD. Use the added helper in drm_dp_mst_rad_to_str() & drm_dp_get_mst_branch_device() to unify the implementation. Cc: Imre Deak <imre.deak@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Harry Wentland <hwentlan@amd.com> Cc: Lyude Paul <lyude@redhat.com> Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> --- drivers/gpu/drm/display/drm_dp_mst_topology.c | 30 +++++++++++++------ 1 file changed, 21 insertions(+), 9 deletions(-)