From c6299b268da0599c2bbce3e71efb5398ffd0a808 Mon Sep 17 00:00:00 2001
From: Michael Sevakis <jethead71@rockbox.org>
Date: Sat, 21 Jan 2017 08:09:48 -0500
Subject: action.c must desist in calling set_cpu_frequency from a tick

The function is neither reentrant nor ISR callable. Instead of
using a ticked-based timeout, have the button driver provide the
unboost after a delay when waiting for a button.

HAVE_GUI_BOOST gets immediate boost after dequeuing any message,
otherwise the queue has to have at least three messages waiting
for it to trigger a boost-- essentially the behavior that existed
but now combined in one place.

Change-Id: I1d924702840f56a1a65abe41fa92b4e753c4e75a
---
 firmware/drivers/button.c | 106 +++++++++++++++++++++++++++++++---------------
 1 file changed, 71 insertions(+), 35 deletions(-)

(limited to 'firmware/drivers/button.c')

diff --git a/firmware/drivers/button.c b/firmware/drivers/button.c
index d47a486b43..fe9040cef8 100644
--- a/firmware/drivers/button.c
+++ b/firmware/drivers/button.c
@@ -371,21 +371,75 @@ static void button_tick(void)
 }
 
 #ifdef HAVE_ADJUSTABLE_CPU_FREQ
+static bool button_boosted = false;
+static long button_unboost_tick;
+#define BUTTON_UNBOOST_TMO HZ
+
 static void button_boost(bool state)
 {
-    static bool boosted = false;
-    
-    if (state && !boosted)
+    if (state)
     {
-        cpu_boost(true);
-        boosted = true;
+        button_unboost_tick = current_tick + BUTTON_UNBOOST_TMO;
+
+        if (!button_boosted)
+        {
+            button_boosted = true;
+            cpu_boost(true);
+        }
     }
-    else if (!state && boosted)
+    else if (!state && button_boosted)
     {
+        button_boosted = false;
         cpu_boost(false);
-        boosted = false;
     }
 }
+
+static void button_queue_wait(struct queue_event *evp, int timeout)
+{
+    /* Loop once after wait time if boosted in order to unboost and wait the
+       full remaining time */
+    do
+    {
+        int ticks = timeout;
+
+        if (ticks == 0) /* TIMEOUT_NOBLOCK */
+            ;
+        else if (ticks > 0)
+        {
+            if (button_boosted && ticks > BUTTON_UNBOOST_TMO)
+                ticks = BUTTON_UNBOOST_TMO;
+
+            timeout -= ticks;
+        }
+        else            /* TIMEOUT_BLOCK (ticks < 0) */
+        {
+            if (button_boosted)
+                ticks = BUTTON_UNBOOST_TMO;
+        }
+
+        queue_wait_w_tmo(&button_queue, evp, ticks);
+        if (evp->id != SYS_TIMEOUT)
+        {
+            /* GUI boost build gets immediate kick, otherwise at least 3
+               messages had to be there */
+        #ifndef HAVE_GUI_BOOST
+            if (queue_count(&button_queue) >= 2)
+        #endif
+                button_boost(true);
+
+            break; 
+        }
+
+        if (button_boosted && TIME_AFTER(current_tick, button_unboost_tick))
+            button_boost(false);
+    }
+    while (timeout);
+}
+#else /* ndef HAVE_ADJUSTABLE_CPU_FREQ */
+static inline void button_queue_wait(struct queue_event *evp, int timeout)
+{
+    queue_wait_w_timeout(&button_queue, evp, timeout);
+}
 #endif /* HAVE_ADJUSTABLE_CPU_FREQ */
 
 int button_queue_count( void )
@@ -396,44 +450,26 @@ int button_queue_count( void )
 long button_get(bool block)
 {
     struct queue_event ev;
-    int pending_count = queue_count(&button_queue);
+    button_queue_wait(&ev, block ? TIMEOUT_BLOCK : TIMEOUT_NOBLOCK);
 
-#ifdef HAVE_ADJUSTABLE_CPU_FREQ
-    /* Control the CPU boost trying to keep queue empty. */
-    if (pending_count == 0)
-        button_boost(false);
-    else if (pending_count > 2)
-        button_boost(true);
-#endif
-    
-    if ( block || pending_count )
-    {
-        queue_wait(&button_queue, &ev);
-        
+    if (ev.id == SYS_TIMEOUT)
+        ev.id = BUTTON_NONE;
+    else
         button_data = ev.data;
-        return ev.id;
-    }
-    
-    return BUTTON_NONE;
+
+    return ev.id;
 }
 
 long button_get_w_tmo(int ticks)
 {
-    struct queue_event ev;
-    
-#ifdef HAVE_ADJUSTABLE_CPU_FREQ
-    /* Be sure to keep boosted state. */
-    if (!queue_empty(&button_queue))
-        return button_get(true);
-    
-    button_boost(false);
-#endif
-    
-    queue_wait_w_tmo(&button_queue, &ev, ticks);
+    struct queue_event ev;    
+    button_queue_wait(&ev, ticks);
+
     if (ev.id == SYS_TIMEOUT)
         ev.id = BUTTON_NONE;
     else
         button_data = ev.data;
+
     return ev.id;
 }
 
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