From: Dhananjay Phadke <dpha...@linux.microsoft.com>

fdt_fixup_kaslr_seed() will update given ofnode with random seed value.
Source for random seed can be TPM or RNG driver in u-boot or sec
firmware (ARM).

Signed-off-by: Dhananjay Phadke <dpha...@linux.microsoft.com>
Signed-off-by: Sean Edmond <senaedm...@microsoft.com>

Signed-off-by: Sean Edmond <seanedm...@microsoft.com>
---

Changes in v6:
- root_ofnode_from_fdt()->ofnode_root_from_fdt()

Changes in v5:
- include dm/ofnode-decl.h instead of dm/ofnode.h

Changes in v3:
- Use event spy to do the FDT fixup

Changes in v2:
- fdt_fixup_kaslr_seed() uses the ofnode API
- Add root_ofnode_from_fdt() to get the root node from an FDT and
  perform error checking on the oftree
- add comments to exported functions

 arch/arm/cpu/armv8/sec_firmware.c | 39 +++++++++++--------------------
 boot/fdt_support.c                | 19 +++++++++++++++
 drivers/core/ofnode.c             | 17 ++++++++++++++
 include/dm/ofnode.h               | 12 ++++++++++
 include/fdt_support.h             |  9 +++++++
 5 files changed, 71 insertions(+), 25 deletions(-)

diff --git a/arch/arm/cpu/armv8/sec_firmware.c 
b/arch/arm/cpu/armv8/sec_firmware.c
index c0e8726346f..5f256939277 100644
--- a/arch/arm/cpu/armv8/sec_firmware.c
+++ b/arch/arm/cpu/armv8/sec_firmware.c
@@ -411,46 +411,35 @@ int sec_firmware_init(const void *sec_firmware_img,
 /*
  * fdt_fix_kaslr - Add kalsr-seed node in Device tree
  * @fdt:               Device tree
- * @eret:              0 in case of error, 1 for success
+ * @eret:              0 for success
  */
 int fdt_fixup_kaslr(void *fdt)
 {
-       int nodeoffset;
-       int err, ret = 0;
-       u8 rand[8];
+       int ret = 0;
 
 #if defined(CONFIG_ARMV8_SEC_FIRMWARE_SUPPORT)
+       u8 rand[8];
+       ofnode root;
+
        /* Check if random seed generation is  supported */
        if (sec_firmware_support_hwrng() == false) {
                printf("WARNING: SEC firmware not running, no kaslr-seed\n");
-               return 0;
+               return -EOPNOTSUPP;
        }
 
-       err = sec_firmware_get_random(rand, 8);
-       if (err < 0) {
+       ret = sec_firmware_get_random(rand, 8);
+       if (ret < 0) {
                printf("WARNING: No random number to set kaslr-seed\n");
-               return 0;
+               return ret;
        }
 
-       err = fdt_check_header(fdt);
-       if (err < 0) {
-               printf("fdt_chosen: %s\n", fdt_strerror(err));
-               return 0;
+       ret = ofnode_root_from_fdt(fdt, &root);
+       if (ret < 0) {
+               printf("WARNING: Unable to get root ofnode\n");
+               return ret;
        }
 
-       /* find or create "/chosen" node. */
-       nodeoffset = fdt_find_or_add_subnode(fdt, 0, "chosen");
-       if (nodeoffset < 0)
-               return 0;
-
-       err = fdt_setprop(fdt, nodeoffset, "kaslr-seed", rand,
-                                 sizeof(rand));
-       if (err < 0) {
-               printf("WARNING: can't set kaslr-seed %s.\n",
-                      fdt_strerror(err));
-               return 0;
-       }
-       ret = 1;
+       ret = fdt_fixup_kaslr_seed(root, rand, sizeof(rand));
 #endif
 
        return ret;
diff --git a/boot/fdt_support.c b/boot/fdt_support.c
index b15d07765fe..49d14a949be 100644
--- a/boot/fdt_support.c
+++ b/boot/fdt_support.c
@@ -631,6 +631,25 @@ void fdt_fixup_ethernet(void *fdt)
        }
 }
 
+int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len)
+{
+       ofnode chosen;
+       int ret;
+
+       /* find or create "/chosen" node. */
+       ret = ofnode_add_subnode(node, "chosen", &chosen);
+       if (ret && ret != -EEXIST)
+               return -ENOENT;
+
+       ret = ofnode_write_prop(chosen, "kaslr-seed", seed, len, true);
+       if (ret) {
+               printf("WARNING: can't set kaslr-seed\n");
+               return ret;
+       }
+
+       return 0;
+}
+
 int fdt_record_loadable(void *blob, u32 index, const char *name,
                        uintptr_t load_addr, u32 size, uintptr_t entry_point,
                        const char *type, const char *os, const char *arch)
diff --git a/drivers/core/ofnode.c b/drivers/core/ofnode.c
index f72ea416cf1..557a4a1b969 100644
--- a/drivers/core/ofnode.c
+++ b/drivers/core/ofnode.c
@@ -966,6 +966,23 @@ ofnode oftree_path(oftree tree, const char *path)
        }
 }
 
+int ofnode_root_from_fdt(void *fdt, ofnode *root_node)
+{
+       oftree tree;
+       /* If OFNODE_MULTI_TREE is not set, and if fdt is not the control FDT,
+        *  oftree_from_fdt() will return NULL
+        */
+       tree = oftree_from_fdt(fdt);
+
+       if (!oftree_valid(tree)) {
+               printf("Cannot create oftree\n");
+               return -EINVAL;
+       }
+       *root_node = oftree_root(tree);
+
+       return 0;
+}
+
 const void *ofnode_read_chosen_prop(const char *propname, int *sizep)
 {
        ofnode chosen_node;
diff --git a/include/dm/ofnode.h b/include/dm/ofnode.h
index 5795115c490..b3bb133df19 100644
--- a/include/dm/ofnode.h
+++ b/include/dm/ofnode.h
@@ -936,6 +936,18 @@ ofnode oftree_path(oftree tree, const char *path);
  */
 ofnode oftree_root(oftree tree);
 
+/**
+ * ofnode_root_from_fdt() - Gets the root ofnode given an FDT blob.
+ *                          Note, this will fail if OFNODE_MULTI_TREE
+ *                          is not set.
+ *
+ * @fdt: Device tree to use
+ * @root_node : Root ofnode
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int ofnode_root_from_fdt(void *fdt, ofnode *root_node);
+
 /**
  * ofnode_read_chosen_prop() - get the value of a chosen property
  *
diff --git a/include/fdt_support.h b/include/fdt_support.h
index 2cd83668982..0624650dcee 100644
--- a/include/fdt_support.h
+++ b/include/fdt_support.h
@@ -11,6 +11,7 @@
        !defined(USE_HOSTCC)
 
 #include <asm/u-boot.h>
+#include <dm/ofnode_decl.h>
 #include <linux/libfdt.h>
 #include <abuf.h>
 
@@ -121,6 +122,14 @@ static inline int fdt_fixup_memory_banks(void *blob, u64 
start[], u64 size[],
 #endif
 
 void fdt_fixup_ethernet(void *fdt);
+
+/*
+ * fdt_fixup_kaslr_seed - Add kaslr-seed node in Device tree
+ * @node:              ofnode
+ * @eret:              0 for success
+ */
+int fdt_fixup_kaslr_seed(ofnode node, const u8 *seed, int len);
+
 int fdt_find_and_setprop(void *fdt, const char *node, const char *prop,
                         const void *val, int len, int create);
 void fdt_fixup_qe_firmware(void *fdt);
-- 
2.42.0

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