[U-Boot] [PATCH v8 11/16] lcd: Add support for flushing LCD fb from dcache after update

[Simon Glass]

This provides an option for the LCD to flush the dcache after each update
(puts, scroll or clear).

Signed-off-by: Simon Glass <sjg at chromium.org>
---
Changes in v8:
- Don't enable cache routines if CONFIG_SYS_DCACHE_OFF is defined

Changes in v4:
- Use lcd_puts() for echoing user input so lcd cached data is flushed

Changes in v3:
- Put the LCD cache flush logic back into lcd_puts()

Changes in v2:
- Put the LCD cache flush logic into lcd_putc() instead of lcd_puts()

 common/lcd.c  |   46 +++++++++++++++++++++++++++++++++++++++-------
 common/main.c |   12 ++++++++++--
 include/lcd.h |    8 ++++++++
 3 files changed, 57 insertions(+), 9 deletions(-)

diff --git a/common/lcd.c b/common/lcd.c
index 37b0393..d2a3e91 100644
--- a/common/lcd.c
+++ b/common/lcd.c
@@ -94,6 +94,9 @@ static void lcd_setbgcolor(int color);
 
 char lcd_is_enabled = 0;
 
+static char lcd_flush_dcache;	/* 1 to flush dcache after each lcd update */
+
+
 #ifdef	NOT_USED_SO_FAR
 static void lcd_getcolreg(ushort regno,
 				ushort *red, ushort *green, ushort *blue);
@@ -102,6 +105,28 @@ static int lcd_getfgcolor(void);
 
 /************************************************************************/
 
+/* Flush LCD activity to the caches */
+void lcd_sync(void)
+{
+	/*
+	 * flush_dcache_range() is declared in common.h but it seems that some
+	 * architectures do not actually implement it. Is there a way to find
+	 * out whether it exists? For now, ARM is safe.
+	 */
+#if defined(CONFIG_ARM) && !defined(CONFIG_SYS_DCACHE_OFF)
+	int line_length;
+
+	if (lcd_flush_dcache)
+		flush_dcache_range((u32)lcd_base,
+			(u32)(lcd_base + lcd_get_size(&line_length)));
+#endif
+}
+
+void lcd_set_flush_dcache(int flush)
+{
+	lcd_flush_dcache = (flush != 0);
+}
+
 /*----------------------------------------------------------------------*/
 
 static void console_scrollup(void)
@@ -111,6 +136,7 @@ static void console_scrollup(void)
 
 	/* Clear the last one */
 	memset(CONSOLE_ROW_LAST, COLOR_MASK(lcd_color_bg), CONSOLE_ROW_SIZE);
+	lcd_sync();
 }
 
 /*----------------------------------------------------------------------*/
@@ -140,6 +166,8 @@ static inline void console_newline(void)
 		/* Scroll everything up */
 		console_scrollup();
 		--console_row;
+	} else {
+		lcd_sync();
 	}
 }
 
@@ -195,6 +223,7 @@ void lcd_puts(const char *s)
 	while (*s) {
 		lcd_putc(*s++);
 	}
+	lcd_sync();
 }
 
 /*----------------------------------------------------------------------*/
@@ -362,13 +391,6 @@ int drv_lcd_init (void)
 }
 
 /*----------------------------------------------------------------------*/
-static
-int do_lcd_clear(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
-{
-	lcd_clear();
-	return 0;
-}
-
 void lcd_clear(void)
 {
 #if LCD_BPP == LCD_MONOCHROME
@@ -410,6 +432,14 @@ void lcd_clear(void)
 
 	console_col = 0;
 	console_row = 0;
+	lcd_sync();
+}
+
+static int do_lcd_clear(cmd_tbl_t *cmdtp, int flag, int argc,
+			char *const argv[])
+{
+	lcd_clear();
+	return 0;
 }
 
 U_BOOT_CMD(
@@ -621,6 +651,7 @@ void bitmap_plot(int x, int y)
 	}
 
 	WATCHDOG_RESET();
+	lcd_sync();
 }
 #else
 static inline void bitmap_plot(int x, int y) {}
@@ -842,6 +873,7 @@ int lcd_display_bitmap(ulong bmp_image, int x, int y)
 		break;
 	};
 
+	lcd_sync();
 	return 0;
 }
 #endif
diff --git a/common/main.c b/common/main.c
index 9507cec..62dbcc5 100644
--- a/common/main.c
+++ b/common/main.c
@@ -1041,8 +1041,16 @@ int readline_into_buffer(const char *const prompt, char *buffer, int timeout)
 					puts (tab_seq+(col&07));
 					col += 8 - (col&07);
 				} else {
-					++col;		/* echo input		*/
-					putc (c);
+					char buf[2];
+
+					/*
+					 * Echo input using puts() to force am
+					 * LCD flush if we are using an LCD
+					 */
+					++col;
+					buf[0] = c;
+					buf[1] = '\0';
+					puts(buf);
 				}
 				*p++ = c;
 				++n;
diff --git a/include/lcd.h b/include/lcd.h
index 6a600ee..8f84741 100644
--- a/include/lcd.h
+++ b/include/lcd.h
@@ -57,6 +57,14 @@ extern void lcd_initcolregs (void);
 extern struct bmp_image *gunzip_bmp(unsigned long addr, unsigned long *lenp);
 extern int bmp_display(ulong addr, int x, int y);
 
+/**
+ * Set whether we need to flush the dcache when changing the LCD image. This
+ * defaults to off.
+ *
+ * @param flush		non-zero to flush cache after update, 0 to skip
+ */
+void lcd_set_flush_dcache(int flush);
+
 #if defined CONFIG_MPC823
 /*
  * LCD controller stucture for MPC823 CPU
-- 
1.7.7.3