Sansa Connect: Use Image Buffer for screen updates.

This improves framerate update (when uboosted, approximate values) from 151 fps to 911 fps for whole screen update and from 432 fps to 3017 fps for quarter screen update.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@31357 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/tms320dm320/sansa-connect/lcd-sansaconnect.c

@@ -153,6 +153,130 @@ void lcd_init_device(void)
     lcd_on = true;
 }
 
+#ifdef LCD_USE_DMA
+static void dma_lcd_copy_buffer_rect(int x, int y, int width, int height)
+{
+    char *dst, *src;
+
+    /* Image buffer A is 4KW, every pixel is one Word */
+    /* lines is maximum number of lines we can transfer in single run */
+    int lines = 4096/width;
+    if (lines > height)
+        lines = height;
+
+    /* Set source and destination addresses */
+    dst = (char*)(FRAME + LCD_WIDTH*y + x);
+    src = (char*)(&lcd_framebuffer[y][x]);
+ 
+    /* Flush cache to memory */
+    commit_dcache();
+
+    /* Addresses are relative to start of SDRAM */
+    src -= CONFIG_SDRAM_START;
+    dst -= CONFIG_SDRAM_START;
+    
+    /* Enable Image Buffer clock */
+    bitset16(&IO_CLK_MOD1, CLK_MOD1_IMGBUF);
+
+    /* Use Image Buffer A for DMA */
+    COP_BUF_MUX0 = (COP_BUF_MUX0 & 0xFFF0) | 0x0003;
+
+    /* Setup buffer offsets and transfer width/height */
+    COP_BUF_LOFST = width;
+    COP_DMA_XNUM  = width;
+    COP_DMA_YNUM  = lines;
+
+    /* DMA: No byte SWAP, no transformation, data bus shift down 0 bit */
+    COP_IMG_MODE &= 0xC0;
+
+    /* Set the start address of buffer */
+    COP_BUF_ADDR = 0x0000;
+    
+    /* Setup SDRAM stride */
+    COP_SDEM_LOFST = LCD_WIDTH;
+
+    do {
+        int addr;
+
+        addr = (int)src;
+        addr >>= 1; /* Addresses are in 16-bit words */
+        
+        /* Setup the registers to initiate the read from SDRAM */
+        COP_SDEM_ADDRH = addr >> 16;
+        COP_SDEM_ADDRL = addr & 0xFFFF;
+        
+        /* Set direction and start */
+        COP_DMA_CTRL = 0x0001;
+        COP_DMA_CTRL |= 0x0002;
+
+        /* Wait for read to finish */
+        while (COP_DMA_CTRL & 0x02) {};
+        
+        addr = (int)dst;
+        addr >>= 1;
+        
+        COP_SDEM_ADDRH = addr >> 16;
+        COP_SDEM_ADDRL = addr & 0xFFFF;
+        
+        /* Set direction and start transfer */
+        COP_DMA_CTRL = 0x0000;
+        COP_DMA_CTRL |= 0x0002;
+        
+        /* Wait for the transfer to complete */
+        while (COP_DMA_CTRL & 0x02) {};
+
+        /* Decrease height, update pointers */
+        src += (LCD_WIDTH << 1)*lines;
+        dst += (LCD_WIDTH << 1)*lines;
+
+        height -= lines;
+        if (height < lines)
+        {
+            lines = height;
+            COP_DMA_YNUM = height;
+        }
+    } while (height > 0);
+
+    /* Disable Image Buffer clock */
+    bitclr16(&IO_CLK_MOD1, CLK_MOD1_IMGBUF);
+}
+
+/* Update a fraction of the display. */
+void lcd_update_rect(int x, int y, int width, int height)
+        __attribute__ ((section(".icode")));
+void lcd_update_rect(int x, int y, int width, int height)
+{
+    if (!lcd_on)
+        return;
+
+    if ((width | height) < 0)
+        return; /* Nothing left to do */
+
+    if (x + width > LCD_WIDTH)
+        width = LCD_WIDTH - x; /* Clip right */
+    if (x < 0)
+        width += x, x = 0; /* Clip left */
+
+    if (y + height > LCD_HEIGHT)
+        height = LCD_HEIGHT - y; /* Clip bottom */
+    if (y < 0)
+        height += y, y = 0; /* Clip top */
+
+    dma_lcd_copy_buffer_rect(x, y, width, height);
+}
+
+/* Update the display.
+   This must be called after all other LCD functions that change the display. */
+void lcd_update(void) __attribute__ ((section(".icode")));
+void lcd_update(void)
+{
+    if (!lcd_on)
+        return;
+
+    lcd_update_rect(0, 0, LCD_WIDTH, LCD_HEIGHT);
+}
+#endif
+
 void lcd_set_contrast(int val) {
   (void) val;
   // TODO:

firmware/target/arm/tms320dm320/sansa-connect/lcd-target.h

@@ -24,6 +24,14 @@
 
 #define LCD_FRAMEBUF_ADDR(col, row) ((fb_data *)FRAME + (row)*LCD_WIDTH + (col))
 
+/* Comment this to remove Image Buffer DMA usage */
+#define LCD_USE_DMA
+
+#ifdef LCD_USE_DMA
+#define LCD_OPTIMIZED_UPDATE
+#define LCD_OPTIMIZED_UPDATE_RECT
+#endif
+
 void lcd_awake(void);
 
 #endif /* LCD_TARGET_H */