xilinx: board: Update the kaslr-seed property

Create a ft_board_setup() api that gets called as part
of bootm/booti before jumping to kernel. In this
ft_board_setup() callback that will inspect the DTB
and insert the device tree blob with the "kaslr-seed" property.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@amd.com>
Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20240117032014.1014084-2-venkatesh.abbarapu@amd.com

1 files changed, 49 insertions, 0 deletions

diff --git a/board/xilinx/common/board.c b/board/xilinx/common/board.c
index 12a877c..9641ed3 100644
--- a/board/xilinx/common/board.c
+++ b/board/xilinx/common/board.c
@@ -25,6 +25,7 @@
 #include <i2c_eeprom.h>
 #include <net.h>
 #include <generated/dt.h>
+#include <rng.h>
 #include <slre.h>
 #include <soc.h>
 #include <linux/ctype.h>
@@ -682,3 +683,51 @@ phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
 	return reg + size;
 }
 #endif
+
+#ifdef CONFIG_OF_BOARD_SETUP
+#define MAX_RAND_SIZE 8
+int ft_board_setup(void *blob, struct bd_info *bd)
+{
+	size_t n = MAX_RAND_SIZE;
+	struct udevice *dev;
+	u8 buf[MAX_RAND_SIZE];
+	int nodeoffset, ret;
+
+	if (uclass_get_device(UCLASS_RNG, 0, &dev) || !dev) {
+		debug("No RNG device\n");
+		return 0;
+	}
+
+	if (dm_rng_read(dev, buf, n)) {
+		debug("Reading RNG failed\n");
+		return 0;
+	}
+
+	if (!blob) {
+		debug("No FDT memory address configured. Please configure\n"
+		      "the FDT address via \"fdt addr <address>\" command.\n"
+		      "Aborting!\n");
+		return 0;
+	}
+
+	ret = fdt_check_header(blob);
+	if (ret < 0) {
+		debug("fdt_chosen: %s\n", fdt_strerror(ret));
+		return ret;
+	}
+
+	nodeoffset = fdt_find_or_add_subnode(blob, 0, "chosen");
+	if (nodeoffset < 0) {
+		debug("Reading chosen node failed\n");
+		return nodeoffset;
+	}
+
+	ret = fdt_setprop(blob, nodeoffset, "kaslr-seed", buf, sizeof(buf));
+	if (ret < 0) {
+		debug("Unable to set kaslr-seed on chosen node: %s\n", fdt_strerror(ret));
+		return ret;
+	}
+
+	return 0;
+}
+#endif