pico-imx7d: Add Falcon mode support

Falcon mode boots the kernel directly from SPL, without loading
the full U-Boot.

As pico-imx7d does not have a GPIO for selecting Falcon versus
normal mode, enter in Falcon mode when the customer selects
the CONFIG_SPL_OS_BOOT option in menuconfig.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>

board/technexion/pico-imx7d/spl.c

@@ -13,6 +13,14 @@
 #include <spl.h>
 
 #if defined(CONFIG_SPL_BUILD)
+
+#ifdef CONFIG_SPL_OS_BOOT
+int spl_start_uboot(void)
+{
+	return 0;
+}
+#endif
+
 static struct ddrc ddrc_regs_val = {
 	.mstr		= 0x01040001,
 	.rfshtmg	= 0x00400046,

configs/pico-imx7d_defconfig

@@ -21,6 +21,8 @@ CONFIG_SPL_USB_SDP_SUPPORT=y
 CONFIG_CMD_BOOTMENU=y
 # CONFIG_CMD_IMI is not set
 # CONFIG_CMD_XIMG is not set
+CONFIG_CMD_SPL=y
+CONFIG_CMD_SPL_WRITE_SIZE=0x20000
 CONFIG_CMD_DFU=y
 CONFIG_CMD_GPIO=y
 CONFIG_CMD_GPT=y

include/configs/pico-imx7d.h

@@ -12,6 +12,18 @@
 
 #include "imx7_spl.h"
 
+#ifdef CONFIG_SPL_OS_BOOT
+/* Falcon Mode */
+#define CONFIG_SPL_FS_LOAD_ARGS_NAME	"args"
+#define CONFIG_SPL_FS_LOAD_KERNEL_NAME	"uImage"
+#define CONFIG_SYS_SPL_ARGS_ADDR	0x88000000
+
+/* Falcon Mode - MMC support: args@1MB kernel@2MB */
+#define CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR  0x800   /* 1MB */
+#define CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS (CONFIG_CMD_SPL_WRITE_SIZE / 512)
+#define CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR        0x1000  /* 2MB */
+#endif
+
 /* Size of malloc() pool */
 #define CONFIG_SYS_MALLOC_LEN		(32 * SZ_1M)