drm/dp: extract drm_dp_dpcd_poll_act_handled()

SST with 128b/132b channel coding needs this too. Extract to a separate
helper, independent of MST.

Pass timeout in as a parameter, anticipating that we can reduce the
timeout for SST.

v2: Clean up kernel-doc a bit

Cc: Lyude Paul <[email protected]>
Reviewed-by: Imre Deak <[email protected]>
Reviewed-by: Lyude Paul <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/459fd3e96a55a8ea8ada8d27d93eaa24c235f9c1.1733238941.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <[email protected]>

1 files changed, 2 insertions, 34 deletions

diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index ac90118b9e7a..2bdbc1eb282b 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -29,7 +29,6 @@
 #include <linux/random.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
-#include <linux/iopoll.h>
 
 #if IS_ENABLED(CONFIG_DRM_DEBUG_DP_MST_TOPOLOGY_REFS)
 #include <linux/stacktrace.h>
@@ -4723,18 +4722,6 @@ fail:
 	return ret;
 }
 
-static int do_get_act_status(struct drm_dp_aux *aux)
-{
-	int ret;
-	u8 status;
-
-	ret = drm_dp_dpcd_readb(aux, DP_PAYLOAD_TABLE_UPDATE_STATUS, &status);
-	if (ret < 0)
-		return ret;
-
-	return status;
-}
-
 /**
  * drm_dp_check_act_status() - Polls for ACT handled status.
  * @mgr: manager to use
@@ -4752,28 +4739,9 @@ int drm_dp_check_act_status(struct drm_dp_mst_topology_mgr *mgr)
 	 * There doesn't seem to be any recommended retry count or timeout in
 	 * the MST specification. Since some hubs have been observed to take
 	 * over 1 second to update their payload allocations under certain
-	 * conditions, we use a rather large timeout value.
+	 * conditions, we use a rather large timeout value of 3 seconds.
 	 */
-	const int timeout_ms = 3000;
-	int ret, status;
-
-	ret = readx_poll_timeout(do_get_act_status, mgr->aux, status,
-				 status & DP_PAYLOAD_ACT_HANDLED || status < 0,
-				 200, timeout_ms * USEC_PER_MSEC);
-	if (ret < 0 && status >= 0) {
-		drm_err(mgr->dev, "Failed to get ACT after %dms, last status: %02x\n",
-			timeout_ms, status);
-		return -EINVAL;
-	} else if (status < 0) {
-		/*
-		 * Failure here isn't unexpected - the hub may have
-		 * just been unplugged
-		 */
-		drm_dbg_kms(mgr->dev, "Failed to read payload table status: %d\n", status);
-		return status;
-	}
-
-	return 0;
+	return drm_dp_dpcd_poll_act_handled(mgr->aux, 3000);
 }
 EXPORT_SYMBOL(drm_dp_check_act_status);