Instead of polling the status register for the AUX status, just enable
the IRQs and signal a completion.

Signed-off-by: Sean Anderson <sean.ander...@linux.dev>
---

(no changes since v3)

Changes in v3:
- New

 drivers/gpu/drm/xlnx/zynqmp_dp.c | 35 +++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 9d61b6b8f2d4..863668642190 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -285,6 +285,7 @@ struct zynqmp_dp_config {
  * @next_bridge: The downstream bridge
  * @config: IP core configuration from DTS
  * @aux: aux channel
+ * @aux_done: Completed when we get an AUX reply or timeout
  * @phy: PHY handles for DP lanes
  * @num_lanes: number of enabled phy lanes
  * @hpd_work: hot plug detection worker
@@ -305,6 +306,7 @@ struct zynqmp_dp {
        struct drm_bridge bridge;
        struct work_struct hpd_work;
        struct work_struct hpd_irq_work;
+       struct completion aux_done;
        struct mutex lock;
 
        struct drm_bridge *next_bridge;
@@ -941,12 +943,15 @@ static int zynqmp_dp_aux_cmd_submit(struct zynqmp_dp *dp, 
u32 cmd, u16 addr,
                                    u8 *buf, u8 bytes, u8 *reply)
 {
        bool is_read = (cmd & AUX_READ_BIT) ? true : false;
+       unsigned long time_left;
        u32 reg, i;
 
        reg = zynqmp_dp_read(dp, ZYNQMP_DP_INTERRUPT_SIGNAL_STATE);
        if (reg & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REQUEST)
                return -EBUSY;
 
+       reinit_completion(&dp->aux_done);
+
        zynqmp_dp_write(dp, ZYNQMP_DP_AUX_ADDRESS, addr);
        if (!is_read)
                for (i = 0; i < bytes; i++)
@@ -961,17 +966,14 @@ static int zynqmp_dp_aux_cmd_submit(struct zynqmp_dp *dp, 
u32 cmd, u16 addr,
        zynqmp_dp_write(dp, ZYNQMP_DP_AUX_COMMAND, reg);
 
        /* Wait for reply to be delivered upto 2ms */
-       for (i = 0; ; i++) {
-               reg = zynqmp_dp_read(dp, ZYNQMP_DP_INTERRUPT_SIGNAL_STATE);
-               if (reg & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY)
-                       break;
+       time_left = wait_for_completion_timeout(&dp->aux_done,
+                                               msecs_to_jiffies(2));
+       if (!time_left)
+               return -ETIMEDOUT;
 
-               if (reg & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY_TIMEOUT ||
-                   i == 2)
-                       return -ETIMEDOUT;
-
-               usleep_range(1000, 1100);
-       }
+       reg = zynqmp_dp_read(dp, ZYNQMP_DP_INTERRUPT_SIGNAL_STATE);
+       if (reg & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY_TIMEOUT)
+               return -ETIMEDOUT;
 
        reg = zynqmp_dp_read(dp, ZYNQMP_DP_AUX_REPLY_CODE);
        if (reply)
@@ -1055,6 +1057,9 @@ static int zynqmp_dp_aux_init(struct zynqmp_dp *dp)
                        (w << ZYNQMP_DP_AUX_CLK_DIVIDER_AUX_FILTER_SHIFT) |
                        (rate / (1000 * 1000)));
 
+       zynqmp_dp_write(dp, ZYNQMP_DP_INT_EN, ZYNQMP_DP_INT_REPLY_RECEIVED |
+                                             ZYNQMP_DP_INT_REPLY_TIMEOUT);
+
        dp->aux.name = "ZynqMP DP AUX";
        dp->aux.dev = dp->dev;
        dp->aux.drm_dev = dp->bridge.dev;
@@ -1072,6 +1077,9 @@ static int zynqmp_dp_aux_init(struct zynqmp_dp *dp)
 static void zynqmp_dp_aux_cleanup(struct zynqmp_dp *dp)
 {
        drm_dp_aux_unregister(&dp->aux);
+
+       zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, ZYNQMP_DP_INT_REPLY_RECEIVED |
+                                             ZYNQMP_DP_INT_REPLY_TIMEOUT);
 }
 
 /* 
-----------------------------------------------------------------------------
@@ -1685,6 +1693,12 @@ static irqreturn_t zynqmp_dp_irq_handler(int irq, void 
*data)
        if (status & ZYNQMP_DP_INT_HPD_IRQ)
                schedule_work(&dp->hpd_irq_work);
 
+       if (status & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY)
+               complete(&dp->aux_done);
+
+       if (status & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY_TIMEOUT)
+               complete(&dp->aux_done);
+
        return IRQ_HANDLED;
 }
 
@@ -1708,6 +1722,7 @@ int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub)
        dp->dpsub = dpsub;
        dp->status = connector_status_disconnected;
        mutex_init(&dp->lock);
+       init_completion(&dp->aux_done);
 
        INIT_WORK(&dp->hpd_work, zynqmp_dp_hpd_work_func);
        INIT_WORK(&dp->hpd_irq_work, zynqmp_dp_hpd_irq_work_func);
-- 
2.35.1.1320.gc452695387.dirty

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