It's possible that an architecture may want to populate
boot_command_line before calling the device tree code.
Currently, early_init_dt_scan_chosen won't accept a NULL
in the data parameter and it returns immediately if you
send one.

I changed early_init_dt_scan_nodes() to send a NULL into
early_init_dt_scan_chosen() , then I made
early_init_dt_scan_chosen() to do the initrd checking, and
the rng-seed checking and skip all the command line related
code.

Given lots of changes to the command line, I think it makes sense
to allow the initrd code and rng-seed code to be run without
forcing the command line handling. I'm also submitting changes
to arm64 which populate boot_command_line much early and this
device tree code overwrites boot_command_line in that case.

This code depends on all architecture to have a NULL
boot_command_line at boot up when this function runs, unless
it's already populated.

This code was boot tested on powerpc 32bit, x86, and arm64.

Cc: xe-linux-exter...@cisco.com
Signed-off-by: Daniel Walker <danie...@cisco.com>
---
 drivers/of/fdt.c | 44 +++++++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index adb26aff481d..a1fda952ce60 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1052,36 +1052,38 @@ int __init early_init_dt_scan_chosen(unsigned long 
node, const char *uname,
 
        pr_debug("search \"chosen\", depth: %d, uname: %s\n", depth, uname);
 
-       if (depth != 1 || !data ||
-           (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
+       if (depth != 1 || (strcmp(uname, "chosen") != 0
+                               && strcmp(uname, "chosen@0") != 0))
                return 0;
 
        early_init_dt_check_for_initrd(node);
 
-       /* Retrieve command line */
-       p = of_get_flat_dt_prop(node, "bootargs", &l);
-       if (p != NULL && l > 0)
-               strlcpy(data, p, min(l, COMMAND_LINE_SIZE));
+       if (data) {
+               /* Retrieve command line */
+               p = of_get_flat_dt_prop(node, "bootargs", &l);
+               if (p != NULL && l > 0)
+                       strlcpy(data, p, min(l, COMMAND_LINE_SIZE));
 
-       /*
-        * CONFIG_CMDLINE is meant to be a default in case nothing else
-        * managed to set the command line, unless CONFIG_CMDLINE_FORCE
-        * is set in which case we override whatever was found earlier.
-        */
+               /*
+                * CONFIG_CMDLINE is meant to be a default in case nothing else
+                * managed to set the command line, unless CONFIG_CMDLINE_FORCE
+                * is set in which case we override whatever was found earlier.
+                */
 #ifdef CONFIG_CMDLINE
 #if defined(CONFIG_CMDLINE_EXTEND)
-       strlcat(data, " ", COMMAND_LINE_SIZE);
-       strlcat(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+               strlcat(data, " ", COMMAND_LINE_SIZE);
+               strlcat(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #elif defined(CONFIG_CMDLINE_FORCE)
-       strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
-#else
-       /* No arguments from boot loader, use kernel's  cmdl*/
-       if (!((char *)data)[0])
                strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#else
+               /* No arguments from boot loader, use kernel's  cmdl*/
+               if (!((char *)data)[0])
+                       strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
 #endif
 #endif /* CONFIG_CMDLINE */
 
-       pr_debug("Command line is: %s\n", (char *)data);
+               pr_debug("Command line is: %s\n", (char *)data);
+       }
 
        rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
        if (rng_seed && l > 0) {
@@ -1202,7 +1204,11 @@ void __init early_init_dt_scan_nodes(void)
        int rc = 0;
 
        /* Retrieve various information from the /chosen node */
-       rc = of_scan_flat_dt(early_init_dt_scan_chosen, boot_command_line);
+       if (boot_command_line[0])
+               rc = of_scan_flat_dt(early_init_dt_scan_chosen, NULL);
+       else
+               rc = of_scan_flat_dt(early_init_dt_scan_chosen,
+                                       boot_command_line);
        if (!rc)
                pr_warn("No chosen node found, continuing without\n");
 
-- 
2.25.1

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