drm: zynqmp_dp: Don't retrain the link in our IRQ

Retraining the link can take a while, and might involve waiting for
DPCD reads/writes to complete. In preparation for unthreading the IRQ
handler, move this into its own work function.

Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240809193600.3360015-4-sean.anderson@linux.dev

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index abfccd8bb5a78d16761d0802d5724a0a1f6dd91b..cec5711c702660f9cc31966cc36fbe6e03b71bd5 100644 (file)
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -289,6 +289,7 @@ struct zynqmp_dp_config {
  * @phy: PHY handles for DP lanes
  * @num_lanes: number of enabled phy lanes
  * @hpd_work: hot plug detection worker
+ * @hpd_irq_work: hot plug detection IRQ worker
  * @status: connection status
  * @enabled: flag to indicate if the device is enabled
  * @dpcd: DP configuration data from currently connected sink device
@@ -304,6 +305,7 @@ struct zynqmp_dp {
        struct drm_dp_aux aux;
        struct drm_bridge bridge;
        struct work_struct hpd_work;
+       struct work_struct hpd_irq_work;
        struct mutex lock;
 
        struct drm_bridge *next_bridge;
@@ -1671,6 +1673,29 @@ static void zynqmp_dp_hpd_work_func(struct work_struct *work)
        drm_bridge_hpd_notify(&dp->bridge, status);
 }
 
+static void zynqmp_dp_hpd_irq_work_func(struct work_struct *work)
+{
+       struct zynqmp_dp *dp = container_of(work, struct zynqmp_dp,
+                                           hpd_irq_work);
+       u8 status[DP_LINK_STATUS_SIZE + 2];
+       int err;
+
+       mutex_lock(&dp->lock);
+       err = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
+                              DP_LINK_STATUS_SIZE + 2);
+       if (err < 0) {
+               dev_dbg_ratelimited(dp->dev,
+                                   "could not read sink status: %d\n", err);
+       } else {
+               if (status[4] & DP_LINK_STATUS_UPDATED ||
+                   !drm_dp_clock_recovery_ok(&status[2], dp->mode.lane_cnt) ||
+                   !drm_dp_channel_eq_ok(&status[2], dp->mode.lane_cnt)) {
+                       zynqmp_dp_train_loop(dp);
+               }
+       }
+       mutex_unlock(&dp->lock);
+}
+
 static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
 {
        struct zynqmp_dp *dp = (struct zynqmp_dp *)data;
@@ -1702,23 +1727,9 @@ static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
        if (status & ZYNQMP_DP_INT_HPD_EVENT)
                schedule_work(&dp->hpd_work);
 
-       if (status & ZYNQMP_DP_INT_HPD_IRQ) {
-               int ret;
-               u8 status[DP_LINK_STATUS_SIZE + 2];
-
-               ret = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
-                                      DP_LINK_STATUS_SIZE + 2);
-               if (ret < 0)
-                       goto handled;
-
-               if (status[4] & DP_LINK_STATUS_UPDATED ||
-                   !drm_dp_clock_recovery_ok(&status[2], dp->mode.lane_cnt) ||
-                   !drm_dp_channel_eq_ok(&status[2], dp->mode.lane_cnt)) {
-                       zynqmp_dp_train_loop(dp);
-               }
-       }
+       if (status & ZYNQMP_DP_INT_HPD_IRQ)
+               schedule_work(&dp->hpd_irq_work);
 
-handled:
        return IRQ_HANDLED;
 }
 
@@ -1744,6 +1755,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub)
        mutex_init(&dp->lock);
 
        INIT_WORK(&dp->hpd_work, zynqmp_dp_hpd_work_func);
+       INIT_WORK(&dp->hpd_irq_work, zynqmp_dp_hpd_irq_work_func);
 
        /* Acquire all resources (IOMEM, IRQ and PHYs). */
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dp");
@@ -1848,6 +1860,7 @@ void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub)
        zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, ZYNQMP_DP_INT_ALL);
        disable_irq(dp->irq);
 
+       cancel_work_sync(&dp->hpd_irq_work);
        cancel_work_sync(&dp->hpd_work);
 
        zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 0);