Fix occasional screen corruption by changing GLCD locking

hardware/emfcamp/sam/libraries/GLCD/gText.cpp

@@ -286,6 +286,9 @@ void gText::ScrollUp(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2,
         return;
     }
 
+    if (this->Acquire() != pdTRUE)
+        return;
+
     for (col = x1; col <= x2; col++) {
         dy = y1;
         glcd_Device::GotoXY(col, dy & ~7);
@@ -366,6 +369,7 @@ void gText::ScrollUp(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2,
             this->WriteData(dbyte);
         }
     }
+    this->Release();
 }
 
 #ifndef GLCD_NO_SCROLLDOWN
@@ -390,6 +394,9 @@ void gText::ScrollDown(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2,
         return;
     }
 
+    if (this->Acquire() != pdTRUE)
+        return;
+
     /*
     * Process region from left to right
     */
@@ -467,6 +474,7 @@ void gText::ScrollDown(uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2,
             this->WriteData(dbyte);
         }
     }
+    this->Release();
 }
 #endif // GLCD_NO_SCROLLDOWN
 
@@ -753,6 +761,9 @@ int gText::PutChar(uint8_t c) {
 
 #ifdef GLCD_OLD_FONTDRAW
     /*================== OLD FONT DRAWING ============================*/
+    if (this->Acquire() != pdTRUE)
+        return 0;
+
     glcd_Device::GotoXY(this->x, this->y);
 
     /*
@@ -805,6 +816,8 @@ int gText::PutChar(uint8_t c) {
     }
     this->x = this->x + width + 1;
 
+    this->Release();
+
 /*================== END of OLD FONT DRAWING ============================*/
 #else
 
@@ -839,6 +852,9 @@ int gText::PutChar(uint8_t c) {
     uint8_t dbyte;
     uint8_t fdata;
 
+    if (this->Acquire() != pdTRUE)
+        return 0;
+
     for (p = 0; p < pixels;) {
         dy = this->y + p;
 
@@ -1036,6 +1052,7 @@ int gText::PutChar(uint8_t c) {
 
     this->x = this->x + width + 1;
 
+    this->Release();
 /*================== END of NEW FONT DRAWING ============================*/
 
 #endif // NEW_FONTDRAW

hardware/emfcamp/sam/libraries/GLCD/glcd.cpp

@@ -362,6 +362,9 @@ void glcd::InvertRect(uint8_t x, uint8_t y, uint8_t width, uint8_t height) {
     /*
      * First do the fractional pages at the top of the region
      */
+    if (this->Acquire() != pdTRUE)
+      return;
+
     this->GotoXY(x, y);
     for (i = 0; i <= width; i++) {
         data = this->ReadData();
@@ -398,6 +401,7 @@ void glcd::InvertRect(uint8_t x, uint8_t y, uint8_t width, uint8_t height) {
             this->WriteData(data);
         }
     }
+    this->Release();
 }
 /**
  * Set LCD Display mode
@@ -438,6 +442,10 @@ void glcd::DrawBitmap(Image_t bitmap, uint8_t x, uint8_t y, uint8_t color) {
 
     width = ReadPgmData(bitmap++);
     height = ReadPgmData(bitmap++);
+
+    if (this->Acquire() != pdTRUE)
+      return;
+
 #define BITMAP_FIX
 #ifdef BITMAP_FIX // temporary ifdef just to show what changes if a new
                   // bit rendering routine is written.
@@ -485,6 +493,7 @@ void glcd::DrawBitmap(Image_t bitmap, uint8_t x, uint8_t y, uint8_t color) {
                 this->WriteData(~displayData);
         }
     }
+    this->Release();
 }
 
 #ifdef NOTYET

hardware/emfcamp/sam/libraries/GLCD/glcd_Device.cpp

@@ -60,6 +60,9 @@ void glcd_Device::SetDot(uint8_t x, uint8_t y, uint8_t color) {
     if ((x >= this->CurrentWidth()) || (y >= this->CurrentHeight()))
         return;
 
+    if (this->Acquire() != pdTRUE)
+        return;
+
     this->GotoXY(x, y - y % 8); // read data from display memory
 
     data = this->ReadData();
@@ -69,6 +72,7 @@ void glcd_Device::SetDot(uint8_t x, uint8_t y, uint8_t color) {
         data &= ~(0x01 << (y % 8)); // clear dot
     }
     this->WriteData(data); // write data back to display
+    this->Release();
 }
 
 /**
@@ -111,6 +115,9 @@ void glcd_Device::SetPixels(uint8_t x, uint8_t y, uint8_t x2, uint8_t y2,
     }
     mask <<= pageOffset;
 
+    if (this->Acquire() != pdTRUE)
+        return;
+
     this->GotoXY(x, y);
     for (i = 0; i < width; i++) {
         data = this->ReadData();
@@ -150,6 +157,7 @@ void glcd_Device::SetPixels(uint8_t x, uint8_t y, uint8_t x2, uint8_t y2,
             this->WriteData(data);
         }
     }
+    this->Release();
 }
 
 /*

hardware/emfcamp/sam/libraries/GLCD/glcd_Device.h

@@ -120,8 +120,6 @@ class glcd_Device : public Print {
   public:
     glcd_Device();
     void WaitForUpdate(void);
-    uint8_t ReadData(void);
-    void WriteData(uint8_t);
     void Init();
     void Display();
     uint8_t CurrentWidth();
@@ -133,7 +131,14 @@ class glcd_Device : public Print {
     void SetDot(uint8_t x, uint8_t y, uint8_t color);
     void SetPixels(uint8_t x, uint8_t y, uint8_t x1, uint8_t y1, uint8_t color);
 
+    uint8_t Acquire(void);
+    void Release(void);
+
+    // These must only be called after a successful Acquire()
+    // Screen will only be updated after Release()
     void GotoXY(uint8_t x, uint8_t y);
+    uint8_t ReadData(void);
+    void WriteData(uint8_t);
 };
 
 #endif

hardware/emfcamp/sam/libraries/GLCD/st7565.cpp

@@ -318,6 +318,7 @@ void glcd_Device::_updateDisplay() {
     }
 }
 
+// Must Acquire() mutex before this is called
 void glcd_Device::GotoXY(uint8_t x, uint8_t y) {
     if ((x > this->CurrentWidth() - 1) ||
         (y > this->CurrentHeight() - 1)) // exit if coordinates are not legal
@@ -328,34 +329,17 @@ void glcd_Device::GotoXY(uint8_t x, uint8_t y) {
     _y = y;
 }
 
-// Never call this directly, as it has no mutex
-uint8_t glcd_Device::_do_ReadData() {
+// Must Acquire() mutex before you call this
+uint8_t glcd_Device::ReadData() {
     if (_x >= this->CurrentWidth()) {
         return (0);
     }
     // Read from the frame buffer
     return this->_framebuffer[_y /8 * this->CurrentWidth() + _x];
 }
 
-uint8_t glcd_Device::ReadData() {
-    uint8_t data;
-    if (xTaskGetSchedulerState() == taskSCHEDULER_RUNNING) {
-        if (frameBufferMutex == 0) {
-            frameBufferMutex = xSemaphoreCreateMutex();
-        }
-        if (xSemaphoreTake(frameBufferMutex, (TickType_t)100) == pdTRUE) {
-            data = _do_ReadData();
-            xSemaphoreGive(frameBufferMutex);
-            return data;
-        } else {
-        }
-    } else {
-        return _do_ReadData();
-    }
-}
-
-// Never call this directly, as it has no mutex
-void glcd_Device::_do_WriteData(uint8_t data) {
+// Must Acquire() mutex before you call this
+void glcd_Device::WriteData(uint8_t data) {
     uint8_t displayData, yOffset, chip;
     uint8_t current_width = this->CurrentWidth();
     if (_x >= current_width) {
@@ -405,22 +389,6 @@ void glcd_Device::_do_WriteData(uint8_t data) {
     }
 }
 
-void glcd_Device::WriteData(uint8_t data) {
-    if (xTaskGetSchedulerState() == taskSCHEDULER_RUNNING) {
-        if (frameBufferMutex == 0) {
-            frameBufferMutex = xSemaphoreCreateMutex();
-        }
-        if (xSemaphoreTake(frameBufferMutex, (TickType_t)100) == pdTRUE) {
-            _do_WriteData(data);
-            xSemaphoreGive(frameBufferMutex);
-        } else {
-        }
-    } else {
-        _do_WriteData(data);
-    }
-    _updateDisplay();
-}
-
 void glcd_Device::WaitForUpdate() {
     uint8_t discard;
     if (xTaskGetSchedulerState() == taskSCHEDULER_RUNNING) {
@@ -471,3 +439,23 @@ void glcd_Device::SetRotation(rotation_t rotation)
 {
   _rotation = rotation;
 }
+
+uint8_t glcd_Device::Acquire(void)
+{
+    if (xTaskGetSchedulerState() == taskSCHEDULER_RUNNING) {
+        if (frameBufferMutex == 0) {
+            frameBufferMutex = xSemaphoreCreateMutex();
+        }
+        return xSemaphoreTake(frameBufferMutex, (TickType_t)100);
+    } else {
+        return pdTRUE;
+    }
+}
+
+void glcd_Device::Release(void)
+{
+    if (frameBufferMutex != 0) {
+        xSemaphoreGive(frameBufferMutex);
+    }
+    _updateDisplay();
+}