Fuze/e200v2: Speed up the LCD further by letting the FIFO fill until it's full instead of keeping it almost empty.

The blue bars I previously had with this way are fixed by blocking DBOP output while reading buttons from GPIO.
We reached the maximum fps even at unboosted now (100.0 fps at lcd_update(), DBOP can't do more). Optimisation to YUV stuff is still possible though.
The e200v2 scrollwheel is very improved due to the this and the previous speedup since the chance of getting the wheel read blocked is greatly decreased with faster updates.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@22578 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/as3525/button-e200v2-fuze.c

@@ -32,7 +32,7 @@
 #define WHEEL_COUNTER_DIV       4
 #define ACCEL_INCREMENT         2
 #define ACCEL_SHIFT             2
-#define BUTTON_DELAY            45
+#define BUTTON_DELAY            30
 #endif
 
 #ifdef SANSA_E200V2
@@ -246,6 +246,11 @@ static int button_gpio(void)
     int btn = BUTTON_NONE;
     if(hold_button)
         return btn;
+
+    /* disable DBOP output while changing GPIO pins that share lines with it */
+    DBOP_CTRL &= ~(1<<16);
+    button_delay();
+    
     /* set afsel, so that we can read our buttons */
     GPIOC_AFSEL &= ~(1<<2|1<<3|1<<4|1<<5|1<<6);
     /* set dir so we can read our buttons (but reset the C pins first) */
@@ -276,7 +281,8 @@ static int button_gpio(void)
     /* return to settings needed for lcd */
     GPIOC_DIR |= (1<<2|1<<3|1<<4|1<<5|1<<6);
     GPIOC_AFSEL |= (1<<2|1<<3|1<<4|1<<5|1<<6);
-
+    
+    DBOP_CTRL |= (1<<16);               /* enable output again */
     return btn;
 }
 

firmware/target/arm/as3525/sansa-e200v2/lcd-e200v2.c

@@ -170,16 +170,16 @@ void lcd_write_data(const fb_data* p_bytes, int count)
         DBOP_DOUT32 = *data++;
         count -= 2;
 
-        /* TODO: We should normally fill the fifo until it's full
+        /* Wait if push fifo is full */
- 	  	* instead of waiting after each word,
+        while ((DBOP_STAT & (1<<6)) != 0);
-                    * but that causes blue lines on the display */                    
-        while ((DBOP_STAT & (1<<10)) == 0);
     }
-    
     /* due to the 32bit alignment requirement, we possibly need to do a
         * 16bit transfer at the end also */
     if (count > 0)
         lcd_write_single_data16(*(fb_data*)data);
+
+    /* While push fifo is not empty */
+    while ((DBOP_STAT & (1<<10)) == 0);
 }
 
 static void lcd_write_reg(int reg, int value)

firmware/target/arm/as3525/sansa-fuze/lcd-fuze.c

@@ -116,16 +116,16 @@ void lcd_write_data(const fb_data* p_bytes, int count)
         DBOP_DOUT32 = *data++;
         count -= 2;
 
-        /* Wait for fifo to empty */
+        /* Wait if push fifo is full */
-        /* TODO: We should normally fill the fifo until it's full
+        while ((DBOP_STAT & (1<<6)) != 0);
-         * instead of waiting after each word,
-         * but that causes blue lines on the display */
-        while ((DBOP_STAT & (1<<10)) == 0);
     }
     /* due to the 32bit alignment requirement, we possibly need to do a
-     * 16bit transfer at the end also */
+        * 16bit transfer at the end also */
     if (count > 0)
         lcd_write_single_data16(*(fb_data*)data);
+
+    /* While push fifo is not empty */
+    while ((DBOP_STAT & (1<<10)) == 0);
 }
 
 static void lcd_write_reg(int reg, int value)