3 files changed, 34 insertions, 42 deletions

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 9063ae6553cc..c1f76f7424ac 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -409,17 +409,6 @@ config ARC_DBG_TLB_MISS_COUNT
           Counts number of I and D TLB Misses and exports them via Debugfs
           The counters can be cleared via Debugfs as well
 
-config CMDLINE_UBOOT
-        bool "Support U-boot kernel command line passing"
-        default n
-        help
-          If you are using U-boot (www.denx.de) and wish to pass the kernel
-          command line from the U-boot environment to the Linux kernel then
-          switch this option on.
-          ARC U-boot will setup the cmdline in RAM/flash and set r2 to point
-          to it. kernel startup code will append this to DeviceTree
-          /bootargs provided cmdline args.
-
 config ARC_BUILTIN_DTB_NAME
         string "Built in DTB"
         help
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 2c878e964a64..991997269d02 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -49,25 +49,13 @@ stext:
         st.ab   0, [r5,4]
         brlt    r5, r6, 1b
 
-#ifdef CONFIG_CMDLINE_UBOOT
-        ; support for bootloader provided cmdline
-        ;    If cmdline passed by u-boot, then
-        ;    r0 = 1  (because ATAGS parsing, now retired, used to use 0)
-        ;    r1 = magic number (board identity)
-        ;    r2 = addr of cmdline string (somewhere in memory/flash)
-
-        brne    r0, 1, .Lother_bootup_chores    ; u-boot didn't pass cmdline
-        breq    r2, 0, .Lother_bootup_chores    ; or cmdline is NULL
-
-        mov     r5, @command_line
-1:
-        ldb.ab  r6, [r2, 1]
-        breq    r6, 0, .Lother_bootup_chores
-        b.d     1b
-        stb.ab  r6, [r5, 1]
-#endif
-
-.Lother_bootup_chores:
+        ; Uboot - kernel ABI
+        ;    r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2
+        ;    r1 = magic number (board identity, unused as of now
+        ;    r2 = pointer to uboot provided cmdline or external DTB in mem
+        ; These are handled later in setup_arch()
+        st      r0, [@uboot_tag]
+        st      r2, [@uboot_arg]
 
         ; Identify if running on ISS vs Silicon
         ;       IDENTITY Reg [ 3  2  1  0 ]
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 643eae4436e0..ffb60b4f6f86 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -29,7 +29,10 @@
 
 int running_on_hw = 1;  /* vs. on ISS */
 
-char __initdata command_line[COMMAND_LINE_SIZE];
+/* Part of U-boot ABI: see head.S */
+int __initdata uboot_tag;
+char __initdata *uboot_arg;
+
 const struct machine_desc *machine_desc;
 
 struct task_struct *_current_task[NR_CPUS];     /* For stack switching */
@@ -311,19 +314,31 @@ void setup_processor(void)
         arc_chk_fpu();
 }
 
+static inline int is_kernel(unsigned long addr)
+{
+        if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
+                return 1;
+        return 0;
+}
+
 void __init setup_arch(char **cmdline_p)
 {
-        /* This also populates @boot_command_line from /bootargs */
-        machine_desc = setup_machine_fdt(__dtb_start);
-        if (!machine_desc)
-                panic("Embedded DT invalid\n");
-
-        /* Append any u-boot provided cmdline */
-#ifdef CONFIG_CMDLINE_UBOOT
-        /* Add a whitespace seperator between the 2 cmdlines */
-        strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
-        strlcat(boot_command_line, command_line, COMMAND_LINE_SIZE);
-#endif
+                machine_desc = setup_machine_fdt(__dtb_start);
+                if (!machine_desc)
+                        panic("Embedded DT invalid\n");
+
+                /*
+                 * Append uboot cmdline to embedded DT cmdline.
+                 * setup_machine_fdt() would have populated @boot_command_line
+                 */
+                if (uboot_tag == 1) {
+                        BUG_ON(is_kernel(unsigned long)uboot_arg);
+
+                        /* Ensure a whitespace between the 2 cmdlines */
+                        strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+                        strlcat(boot_command_line, uboot_arg,
+                                COMMAND_LINE_SIZE);
+                }
 
         /* Save unparsed command line copy for /proc/cmdline */
         *cmdline_p = boot_command_line;