drm: dp helper: extract drm_dp_channel_eq_ok

radeon and intel use the exact same definition.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 50 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index bb4eaf60117f..1378b789bd10 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -205,3 +205,53 @@ i2c_dp_aux_add_bus(struct i2c_adapter *adapter)
         return error;
 }
 EXPORT_SYMBOL(i2c_dp_aux_add_bus);
+
+/* Helpers for DP link training */
+static u8 dp_link_status(u8 link_status[DP_LINK_STATUS_SIZE], int r)
+{
+        return link_status[r - DP_LANE0_1_STATUS];
+}
+
+static u8 dp_get_lane_status(u8 link_status[DP_LINK_STATUS_SIZE],
+                             int lane)
+{
+        int i = DP_LANE0_1_STATUS + (lane >> 1);
+        int s = (lane & 1) * 4;
+        u8 l = dp_link_status(link_status, i);
+        return (l >> s) & 0xf;
+}
+
+bool drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE],
+                          int lane_count)
+{
+        u8 lane_align;
+        u8 lane_status;
+        int lane;
+
+        lane_align = dp_link_status(link_status,
+                                    DP_LANE_ALIGN_STATUS_UPDATED);
+        if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)
+                return false;
+        for (lane = 0; lane < lane_count; lane++) {
+                lane_status = dp_get_lane_status(link_status, lane);
+                if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS)
+                        return false;
+        }
+        return true;
+}
+EXPORT_SYMBOL(drm_dp_channel_eq_ok);
+
+bool drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE],
+                              int lane_count)
+{
+        int lane;
+        u8 lane_status;
+
+        for (lane = 0; lane < lane_count; lane++) {
+                lane_status = dp_get_lane_status(link_status, lane);
+                if ((lane_status & DP_LANE_CR_DONE) == 0)
+                        return false;
+        }
+        return true;
+}
+EXPORT_SYMBOL(drm_dp_clock_recovery_ok);