spi: Go back to immediate teardown

Commit 412e6037324 ("spi: core: avoid waking pump thread from spi_sync
instead run teardown delayed") introduced regressions on some boards,
apparently connected to spi_mem not triggering shutdown properly any
more.  Since we've thus far been unable to figure out exactly where the
breakage is revert the optimisation for now.

Reported-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: kernel@martin.sperl.org

1 files changed, 33 insertions, 89 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 06b9139664a3..13f447a67d67 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1225,7 +1225,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
                 return;
         }
 
-        /* If another context is idling the device then defer to kthread */
+        /* If another context is idling the device then defer */
         if (ctlr->idling) {
                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
@@ -1239,10 +1239,34 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread)
                         return;
                 }
 
-                /* schedule idle teardown with a delay of 1 second */
-                kthread_mod_delayed_work(&ctlr->kworker,
-                                         &ctlr->pump_idle_teardown,
-                                         HZ);
+                /* Only do teardown in the thread */
+                if (!in_kthread) {
+                        kthread_queue_work(&ctlr->kworker,
+                                           &ctlr->pump_messages);
+                        spin_unlock_irqrestore(&ctlr->queue_lock, flags);
+                        return;
+                }
+
+                ctlr->busy = false;
+                ctlr->idling = true;
+                spin_unlock_irqrestore(&ctlr->queue_lock, flags);
+
+                kfree(ctlr->dummy_rx);
+                ctlr->dummy_rx = NULL;
+                kfree(ctlr->dummy_tx);
+                ctlr->dummy_tx = NULL;
+                if (ctlr->unprepare_transfer_hardware &&
+                    ctlr->unprepare_transfer_hardware(ctlr))
+                        dev_err(&ctlr->dev,
+                                "failed to unprepare transfer hardware\n");
+                if (ctlr->auto_runtime_pm) {
+                        pm_runtime_mark_last_busy(ctlr->dev.parent);
+                        pm_runtime_put_autosuspend(ctlr->dev.parent);
+                }
+                trace_spi_controller_idle(ctlr);
+
+                spin_lock_irqsave(&ctlr->queue_lock, flags);
+                ctlr->idling = false;
                 spin_unlock_irqrestore(&ctlr->queue_lock, flags);
                 return;
         }
@@ -1335,77 +1359,6 @@ static void spi_pump_messages(struct kthread_work *work)
         __spi_pump_messages(ctlr, true);
 }
 
-/**
- * spi_pump_idle_teardown - kthread delayed work function which tears down
- *                          the controller settings after some delay
- * @work: pointer to kthread work struct contained in the controller struct
- */
-static void spi_pump_idle_teardown(struct kthread_work *work)
-{
-        struct spi_controller *ctlr =
-                container_of(work, struct spi_controller,
-                             pump_idle_teardown.work);
-        unsigned long flags;
-
-        /* Lock queue */
-        spin_lock_irqsave(&ctlr->queue_lock, flags);
-
-        /* Make sure we are not already running a message */
-        if (ctlr->cur_msg)
-                goto out;
-
-        /* if there is anything in the list then exit */
-        if (!list_empty(&ctlr->queue))
-                goto out;
-
-        /* if the controller is running then exit */
-        if (ctlr->running)
-                goto out;
-
-        /* if the controller is busy then exit */
-        if (ctlr->busy)
-                goto out;
-
-        /* if the controller is idling then exit
-         * this is actually a bit strange and would indicate that
-         * this function is scheduled twice, which should not happen
-         */
-        if (ctlr->idling)
-                goto out;
-
-        /* set up the initial states */
-        ctlr->busy = false;
-        ctlr->idling = true;
-        spin_unlock_irqrestore(&ctlr->queue_lock, flags);
-
-        /* free dummy receive buffers */
-        kfree(ctlr->dummy_rx);
-        ctlr->dummy_rx = NULL;
-        kfree(ctlr->dummy_tx);
-        ctlr->dummy_tx = NULL;
-
-        /* unprepare hardware */
-        if (ctlr->unprepare_transfer_hardware &&
-            ctlr->unprepare_transfer_hardware(ctlr))
-                dev_err(&ctlr->dev,
-                        "failed to unprepare transfer hardware\n");
-        /* handle pm */
-        if (ctlr->auto_runtime_pm) {
-                pm_runtime_mark_last_busy(ctlr->dev.parent);
-                pm_runtime_put_autosuspend(ctlr->dev.parent);
-        }
-
-        /* mark controller as idle */
-        trace_spi_controller_idle(ctlr);
-
-        /* finally put us from idling into stopped */
-        spin_lock_irqsave(&ctlr->queue_lock, flags);
-        ctlr->idling = false;
-
-out:
-        spin_unlock_irqrestore(&ctlr->queue_lock, flags);
-}
-
 static int spi_init_queue(struct spi_controller *ctlr)
 {
         struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
@@ -1421,8 +1374,7 @@ static int spi_init_queue(struct spi_controller *ctlr)
                 return PTR_ERR(ctlr->kworker_task);
         }
         kthread_init_work(&ctlr->pump_messages, spi_pump_messages);
-        kthread_init_delayed_work(&ctlr->pump_idle_teardown,
-                                  spi_pump_idle_teardown);
+
         /*
          * Controller config will indicate if this controller should run the
          * message pump with high (realtime) priority to reduce the transfer
@@ -1494,16 +1446,7 @@ void spi_finalize_current_message(struct spi_controller *ctlr)
         spin_lock_irqsave(&ctlr->queue_lock, flags);
         ctlr->cur_msg = NULL;
         ctlr->cur_msg_prepared = false;
-
-        /* if there is something queued, then wake the queue */
-        if (!list_empty(&ctlr->queue))
-                kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
-        else
-                /* otherwise schedule delayed teardown */
-                kthread_mod_delayed_work(&ctlr->kworker,
-                                         &ctlr->pump_idle_teardown,
-                                         HZ);
-
+        kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
 
         trace_spi_message_done(mesg);
@@ -1608,7 +1551,7 @@ static int __spi_queued_transfer(struct spi_device *spi,
         msg->status = -EINPROGRESS;
 
         list_add_tail(&msg->queue, &ctlr->queue);
-        if (need_pump)
+        if (!ctlr->busy && need_pump)
                 kthread_queue_work(&ctlr->kworker, &ctlr->pump_messages);
 
         spin_unlock_irqrestore(&ctlr->queue_lock, flags);
@@ -3783,3 +3726,4 @@ err0:
  * include needing to have boardinfo data structures be much more public.
  */
 postcore_initcall(spi_init);
+