video: dcu: fix framebuffer to the end of memory

Fix the framebuffer location to the very end of the available memory.
This allows to remove the area from available memory for the kernel,
which in turn allows to display the splash screen through the while
Linux kernel boot process.

Ideas has been taken from the sunxi display driver, e.g.
20779ec3a5 ("sunxi: video: Dynamically reserve framebuffer memory")

4 files changed, 49 insertions, 4 deletions

diff --git a/board/toradex/colibri_vf/colibri_vf.c b/board/toradex/colibri_vf/colibri_vf.c
index aef8511aa9..8cbc523145 100644
--- a/board/toradex/colibri_vf/colibri_vf.c
+++ b/board/toradex/colibri_vf/colibri_vf.c
@@ -17,6 +17,7 @@
 #include <asm/imx-common/boot_mode.h>
 #include <mmc.h>
 #include <fsl_esdhc.h>
+#include <fsl_dcu_fb.h>
 #include <miiphy.h>
 #include <netdev.h>
 #include <i2c.h>
@@ -462,3 +463,10 @@ int g_dnl_bind_fixup(struct usb_device_descriptor *dev, const char *name)
 
 	return 0;
 }
+
+#if defined(CONFIG_OF_LIBFDT) && defined(CONFIG_OF_BOARD_SETUP)
+int ft_board_setup(void *blob, bd_t *bd)
+{
+	return fsl_dcu_fixedfb_setup(blob);
+}
+#endif
diff --git a/drivers/video/fsl_dcu_fb.c b/drivers/video/fsl_dcu_fb.c
index 530656e190..73285f55a9 100644
--- a/drivers/video/fsl_dcu_fb.c
+++ b/drivers/video/fsl_dcu_fb.c
@@ -6,8 +6,10 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
+#include <asm/errno.h>
 #include <asm/io.h>
 #include <common.h>
+#include <fdt_support.h>
 #include <fsl_dcu_fb.h>
 #include <linux/fb.h>
 #include <malloc.h>
@@ -79,6 +81,8 @@
 #define BPP_24_RGB888			5
 #define BPP_32_ARGB8888			6
 
+DECLARE_GLOBAL_DATA_PTR;
+
 /*
  * This setting is used for the TWR_LCD_RGB card
  */
@@ -268,11 +272,16 @@ int fsl_dcu_init(unsigned int xres, unsigned int yres,
 	struct dcu_reg *regs = (struct dcu_reg *)CONFIG_SYS_DCU_ADDR;
 	unsigned int div, mode;
 
-	/* Memory allocation for framebuffer */
 	info.screen_size =
 		info.var.xres * info.var.yres * (info.var.bits_per_pixel / 8);
-	info.screen_base = (char *)memalign(ARCH_DMA_MINALIGN,
-			roundup(info.screen_size, ARCH_DMA_MINALIGN));
+
+	if (info.screen_size > CONFIG_FSL_DCU_MAX_FB_SIZE)
+		return -ENOMEM;
+
+	/* Reserve framebuffer at the end of memory */
+	gd->fb_base = gd->bd->bi_dram[0].start +
+		      gd->bd->bi_dram[0].size - info.screen_size;
+	info.screen_base = (char *)gd->fb_base;
 	memset(info.screen_base, 0, info.screen_size);
 
 	reset_total_layers();
@@ -322,6 +331,11 @@ int fsl_dcu_init(unsigned int xres, unsigned int yres,
 	return 0;
 }
 
+ulong board_get_usable_ram_top(ulong total_size)
+{
+	return gd->ram_top - CONFIG_FSL_DCU_MAX_FB_SIZE;
+}
+
 void *video_hw_init(void)
 {
 	static GraphicDevice ctfb;
@@ -384,3 +398,21 @@ void *video_hw_init(void)
 
 	return &ctfb;
 }
+
+#if defined(CONFIG_OF_BOARD_SETUP)
+int fsl_dcu_fixedfb_setup(void *blob)
+{
+	u64 start, size;
+	int ret;
+
+	start = gd->bd->bi_dram[0].start;
+	size = gd->fb_base - gd->bd->bi_dram[0].start;
+	ret = fdt_fixup_memory_banks(blob, &start, &size, 1);
+	if (ret) {
+		eprintf("Cannot setup fb: Error reserving memory\n");
+		return ret;
+	}
+
+	return 0;
+}
+#endif
diff --git a/include/configs/colibri_vf.h b/include/configs/colibri_vf.h
index 007f09ebe3..11a6eeac89 100644
--- a/include/configs/colibri_vf.h
+++ b/include/configs/colibri_vf.h
@@ -14,6 +14,7 @@
 
 #include <asm/arch/imx-regs.h>
 #include <config_cmd_default.h>
+#include <linux/sizes.h>
 
 #define CONFIG_VF610
 #define CONFIG_SYS_THUMB_BUILD
@@ -34,6 +35,8 @@
 #define CONFIG_MXC_OCOTP
 #endif
 
+#define CONFIG_OF_BOARD_SETUP
+
 #define CONFIG_FSL_DCU_FB
 
 #ifdef CONFIG_FSL_DCU_FB
@@ -50,6 +53,7 @@
 
 #define CONFIG_SYS_FSL_DCU_LE
 #define CONFIG_SYS_DCU_ADDR		DCU0_BASE_ADDR
+#define CONFIG_FSL_DCU_MAX_FB_SIZE	(4 * SZ_1M)
 #define DCU_TOTAL_LAYER_NUM		64
 #define DCU_LAYER_MAX_NUM		6
 #endif
@@ -217,7 +221,7 @@
  * Stack sizes
  * The stack sizes are set up in start.S using the settings below
  */
-#define CONFIG_STACKSIZE		(128 * 1024)	/* regular stack */
+#define CONFIG_STACKSIZE		SZ_256K
 
 /* Physical memory map */
 #define CONFIG_NR_DRAM_BANKS		1
diff --git a/include/fsl_dcu_fb.h b/include/fsl_dcu_fb.h
index 42632984d3..67e29e74e6 100644
--- a/include/fsl_dcu_fb.h
+++ b/include/fsl_dcu_fb.h
@@ -9,6 +9,7 @@
 
 int fsl_dcu_init(unsigned int xres, unsigned int yres,
 		 unsigned int pixel_format);
+int fsl_dcu_fixedfb_setup(void *blob);
 
 /* Prototypes for external board-specific functions */
 int platform_dcu_init(unsigned int xres, unsigned int yres,