arm64: versal: Set initrd_high to as high as possible

This patch is setting up the initrd_high to as high as possible by leaving
max stack size for u-boot so that bigger rootfs can also be loaded by
u-boot for booting kernel.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/Kconfig

@@ -462,6 +462,22 @@ config TPL_USE_ARCH_MEMSET
 	  Such implementation may be faster under some conditions
 	  but may increase the binary size.
 
+config SET_STACK_SIZE
+	bool "Enable an option to set max stack size that can be used"
+	default y if ARCH_VERSAL
+	help
+	  This will enable an option to set max stack size that can be
+	  used by u-boot.
+
+config STACK_SIZE
+	hex "Define max stack size that can be used by u-boot"
+	depends on SET_STACK_SIZE
+	default 0x4000000 if ARCH_VERSAL
+	help
+	  Defines Max stack size that can be used by u-boot so that the
+	  initrd_high will be calculated as base stack pointer minus this
+	  stack size.
+
 config ARM64_SUPPORT_AARCH32
 	bool "ARM64 system support AArch32 execution state"
 	depends on ARM64

board/xilinx/versal/board.c

@@ -12,6 +12,7 @@
 #include <dm/device.h>
 #include <dm/uclass.h>
 #include <versalpl.h>
+#include <linux/sizes.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -88,6 +89,7 @@ int board_late_init(void)
 	const char *mode;
 	char *new_targets;
 	char *env_targets;
+	ulong initrd_hi;
 
 	if (!(gd->flags & GD_FLG_ENV_DEFAULT)) {
 		debug("Saved variables - Skipping\n");
@@ -183,6 +185,10 @@ int board_late_init(void)
 
 	env_set("boot_targets", new_targets);
 
+	initrd_hi = gd->start_addr_sp - CONFIG_STACK_SIZE;
+	initrd_hi = round_down(initrd_hi, SZ_16M);
+	env_set_addr("initrd_high", (void *)initrd_hi);
+
 	return 0;
 }
 

include/configs/xilinx_versal.h

@@ -65,7 +65,6 @@
 
 #define ENV_MEM_LAYOUT_SETTINGS \
 	"fdt_high=10000000\0" \
-	"initrd_high=10000000\0" \
 	"fdt_addr_r=0x40000000\0" \
 	"pxefile_addr_r=0x10000000\0" \
 	"kernel_addr_r=0x18000000\0" \