u-boot-starfive: vf2: Update uEnv.txt

Align uEnv.txt with the Starfive SDK to boot from SD card.
uEnv sets required variables to read the fitImage from the
partition 3 on the SD card and rootfs is expected on the
partition 4.

Signed-off-by: Alexey Firago <alexey.firago@gmail.com>

recipes-bsp/u-boot/u-boot-starfive/uEnv-visionfive2.txt

@@ -1,14 +1,22 @@
-fdt_high=0xffffffffffffffff
-initrd_high=0xffffffffffffffff
-kernel_addr_r=0x44000000
-kernel_comp_addr_r=0x90000000
-kernel_comp_size=0x10000000
-fdt_addr_r=0x48000000
-ramdisk_addr_r=0x48100000
-# Move distro to first boot to speed up booting
-boot_targets=distro mmc0 dhcp
-# Fix wrong fdtfile name
-fdtfile=starfive/jh7110-visionfive-v2.dtb
-# Fix missing bootcmd
-bootcmd=run bootcmd_distro
-bootargs=root=/dev/mmcblk1p2 rw console=tty0 console=ttyS0,115200 earlycon rootwait stmmaceth=chain_mode:1 selinux=0
+# This is the sample jh7110_uEnv.txt file for starfive visionfive U-boot
+# The current convention (SUBJECT TO CHANGE) is that this file
+# will be loaded from the third partition on the
+# MMC card.
+#devnum=1
+partnum=3
+
+# The FIT file to boot from
+fitfile=fitImage
+
+# for debugging boot
+bootargs_ext=if test ${devnum} = 0; then setenv bootargs "earlyprintk console=ttyS0,115200 debug rootwait earlycon=sbi root=/dev/mmcblk0p4"; else setenv bootargs "earlyprintk console=ttyS0,115200 debug rootwait earlycon=sbi root=/dev/mmcblk1p4"; fi;
+
+# for addr info
+fileaddr=0xa0000000
+fdtaddr=0x46000000
+# boot Linux flat or compressed 'Image' stored at 'kernel_addr_r'
+kernel_addr_r=0x40200000
+
+bootwait=setenv _delay ${bootdelay}; echo ${_delay}; while test ${_delay} > 0; do sleep 1; setexpr _delay ${_delay} - 1; echo ${_delay}; done
+
+boot2=run bootargs_ext; mmc dev ${devnum}; fatload mmc ${devnum}:${partnum} ${fileaddr} ${fitfile}; bootm ${fileaddr}