arm: vexpress64: juno: Enable distro_bootcmd functionality

The ARM Juno boards can be used as somewhat decent machines to run
off-the-shelf distributions, with USB, SATA, GBit Ethernet and 8GB of
DRAM.

With stable DTs in the board's NOR flash this would work really nicely,
however the default boot command is to fetch a kernel and an initrd from
the on-board NOR flash, which sounds somewhat embedded.

Include the config_distro_bootcmd.h header and define the available
devices (starting with USB, to catch USB installer sticks) to make
distributions and UEFI work out of the box.
The NOR flash kernel functionality is still preserved as the last
resort, should all other methods fail.
Signed-off-by: NAndre Przywara <andre.przywara@arm.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

include/configs/vexpress_aemv8a.h

@@ -126,6 +126,39 @@
 
 /* Initial environment variables */
 #ifdef CONFIG_TARGET_VEXPRESS64_JUNO
+/* Copy the kernel and FDT to DRAM memory and boot */
+#define BOOTENV_DEV_AFS(devtypeu, devtypel, instance) \
+	"bootcmd_afs="							\
+		"afs load ${kernel_name} ${kernel_addr_r} ;"\
+		"if test $? -eq 1; then "\
+		"  echo Loading ${kernel_alt_name} instead of ${kernel_name}; "\
+		"  afs load ${kernel_alt_name} ${kernel_addr_r};"\
+		"fi ; "\
+		"afs load ${fdtfile} ${fdt_addr_r} ;"\
+		"if test $? -eq 1; then "\
+		"  echo Loading ${fdt_alt_name} instead of ${fdtfile}; "\
+		"  afs load ${fdt_alt_name} ${fdt_addr_r}; "\
+		"fi ; "\
+		"fdt addr ${fdt_addr_r}; fdt resize; " \
+		"if afs load  ${ramdisk_name} ${ramdisk_addr_r} ; "\
+		"then "\
+		"  setenv ramdisk_param ${ramdisk_addr_r}; "\
+		"else "\
+		"  setenv ramdisk_param -; "\
+		"fi ; " \
+		"booti ${kernel_addr_r} ${ramdisk_param} ${fdt_addr_r}\0"
+#define BOOTENV_DEV_NAME_AFS(devtypeu, devtypel, instance) "afs "
+
+#define BOOT_TARGET_DEVICES(func)	\
+	func(USB, usb, 0)		\
+	func(SATA, sata, 0)		\
+	func(SATA, sata, 1)		\
+	func(PXE, pxe, na)		\
+	func(DHCP, dhcp, na)		\
+	func(AFS, afs, na)
+
+#include <config_distro_bootcmd.h>
+
 /*
  * Defines where the kernel and FDT exist in NOR flash and where it will
  * be copied into DRAM
@@ -139,30 +172,7 @@
 				"fdtfile=board.dtb\0" \
 				"fdt_alt_name=juno\0" \
 				"fdt_addr_r=0x80000000\0" \
-
-#ifndef CONFIG_BOOTCOMMAND
-/* Copy the kernel and FDT to DRAM memory and boot */
-#define CONFIG_BOOTCOMMAND	"afs load ${kernel_name} ${kernel_addr_r} ;"\
-				"if test $? -eq 1; then "\
-				"  echo Loading ${kernel_alt_name} instead of "\
-				"${kernel_name}; "\
-				"  afs load ${kernel_alt_name} ${kernel_addr_r};"\
-				"fi ; "\
-				"afs load ${fdtfile} ${fdt_addr_r} ;"\
-				"if test $? -eq 1; then "\
-				"  echo Loading ${fdt_alt_name} instead of "\
-				"${fdtfile}; "\
-				"  afs load ${fdt_alt_name} ${fdt_addr_r}; "\
-				"fi ; "\
-				"fdt addr ${fdt_addr_r}; fdt resize; " \
-				"if afs load  ${ramdisk_name} ${ramdisk_addr_r} ; "\
-				"then "\
-				"  setenv ramdisk_param ${ramdisk_addr_r}; "\
-				"  else setenv ramdisk_param -; "\
-				"fi ; " \
-				"booti ${kernel_addr_r} ${ramdisk_param} ${fdt_addr_r}"
-#endif
-
+				BOOTENV
 
 #elif CONFIG_TARGET_VEXPRESS64_BASE_FVP
 #define CONFIG_EXTRA_ENV_SETTINGS	\