[U-Boot] [PATCH v2 13/19] lcd: Add CONFIG_LCD_ALIGNMENT to select frame buffer alignment

[Simon Glass]

The normal alignment is PAGE_SIZE, but if this is defined, we can support
other alignments.

The motivation for this change is to make the display section-aligned on
ARM so that we can easily turn off data caching for the frame buffer region
without resorting to level 2 page tables.

Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v2:
- Use a more generic config CONFIG_LCD_ALIGNMENT for lcd alignment

 README        |   10 ++++++++++
 common/lcd.c  |   24 +++++++++++++++++++-----
 include/lcd.h |    3 +++
 3 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/README b/README
index 67dc444..ccdddbf 100644
--- a/README
+++ b/README
@@ -1398,6 +1398,16 @@ The following options need to be configured:
 		Normally display is black on white background; define
 		CONFIG_SYS_WHITE_ON_BLACK to get it inverted.
 
+
+		CONFIG_LCD_ALIGNMENT
+
+		Normally the LCD is page-aligned (tyically 4KB). If this is
+		defined then the LCD will be aligned to this value instead.
+		For ARM it is sometimes useful to use MMU_SECTION_SIZE
+		here, since it is cheaper to change data cache settings on
+		a per-section basis.
+
+
 - Splash Screen Support: CONFIG_SPLASH_SCREEN
 
 		If this option is set, the environment is checked for
diff --git a/common/lcd.c b/common/lcd.c
index bf1a6a9..c915a49 100644
--- a/common/lcd.c
+++ b/common/lcd.c
@@ -35,6 +35,9 @@
 #include <stdarg.h>
 #include <linux/types.h>
 #include <stdio_dev.h>
+#ifdef CONFIG_ARM
+#include <asm/system.h>
+#endif
 #if defined(CONFIG_POST)
 #include <post.h>
 #endif
@@ -72,6 +75,10 @@
 # endif
 #endif
 
+#ifndef CONFIG_LCD_ALIGNMENT
+#define CONFIG_LCD_ALIGNMENT PAGE_SIZE
+#endif
+
 DECLARE_GLOBAL_DATA_PTR;
 
 ulong lcd_setmem (ulong addr);
@@ -330,6 +337,12 @@ static void test_pattern (void)
 /* ** GENERIC Initialization Routines					*/
 /************************************************************************/
 
+int lcd_get_size(int *line_length)
+{
+	*line_length = (panel_info.vl_col * NBITS(panel_info.vl_bpix)) / 8;
+	return *line_length * panel_info.vl_row;
+}
+
 int drv_lcd_init (void)
 {
 	struct stdio_dev lcddev;
@@ -337,7 +350,7 @@ int drv_lcd_init (void)
 
 	lcd_base = (void *)(gd->fb_base);
 
-	lcd_line_length = (panel_info.vl_col * NBITS (panel_info.vl_bpix)) / 8;
+	lcd_get_size(&lcd_line_length);
 
 	lcd_init (lcd_base);		/* LCD initialization */
 
@@ -449,15 +462,16 @@ static int lcd_init (void *lcdbase)
 ulong lcd_setmem (ulong addr)
 {
 	ulong size;
-	int line_length = (panel_info.vl_col * NBITS (panel_info.vl_bpix)) / 8;
+	int line_length;
 
 	debug ("LCD panel info: %d x %d, %d bit/pix\n",
 		panel_info.vl_col, panel_info.vl_row, NBITS (panel_info.vl_bpix) );
 
-	size = line_length * panel_info.vl_row;
+	size = lcd_get_size(&line_length);
 
-	/* Round up to nearest full page */
-	size = (size + (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
+	/* Round up to nearest full page, or MMU section if defined */
+	size = ALIGN(size, CONFIG_LCD_ALIGNMENT);
+	addr = ALIGN(addr - CONFIG_LCD_ALIGNMENT + 1, CONFIG_LCD_ALIGNMENT);
 
 	/* Allocate pages for the frame buffer. */
 	addr -= size;
diff --git a/include/lcd.h b/include/lcd.h
index 3d9ef16..5016d6b 100644
--- a/include/lcd.h
+++ b/include/lcd.h
@@ -281,6 +281,9 @@ int	lcd_display_bitmap(ulong bmp_image, int x, int y);
 /* Allow boards to customize the information displayed */
 void lcd_show_board_info(void);
 
+/* Return the size of the LCD frame buffer, and the line length */
+int lcd_get_size(int *line_length);
+
 /************************************************************************/
 /* ** BITMAP DISPLAY SUPPORT						*/
 /************************************************************************/
-- 
1.7.7.3