diff options
| author | Wayne Lin <Wayne.Lin@amd.com> | 2025-01-13 17:11:00 +0800 |
|---|---|---|
| committer | Lyude Paul <lyude@redhat.com> | 2025-01-24 17:50:34 -0500 |
| commit | 580aa2782c5b9eb50cb3bf936bc57ec0bf7d55db (patch) | |
| tree | cb2d5b37e1c5cff91e9508f7704e606cd50fc405 | |
| parent | 6bbce873a9c97cb12f5455c497be279ac58e707f (diff) | |
drm/dp_mst: Add helper to get port number at specific LCT from RAD
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.
V2:
- Adjust the code format (Lyude)
V3:
- Adjust parameter "rad" of drm_dp_mst_get_ufp_num_at_lct_from_rad() to
be constant (Kernel test robot)
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>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
[fixed commit message typo]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250113091100.3314533-3-Wayne.Lin@amd.com
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_mst_topology.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 271a00b81264..e79f4b76ec2b 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -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, const 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 +2556,8 @@ 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) { |