arm: Reduce the scope of lowlevel_init()

This function has grown into something of a monster. Some boards are setting
up a console and DRAM here in SPL. This requires global_data which should be
set up in one place (crt0.S).

There is no need for SPL to use s_init() for anything since board_init_f()
is called immediately afterwards.

Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/arch/arm/cpu/armv7/lowlevel_init.S b/arch/arm/cpu/armv7/lowlevel_init.S
index d71c84fae5b85adcd7d170542728973a1e87e734..1db673754dcb115fff9835ad4dfdf667d2febf67 100644 (file)
--- a/arch/arm/cpu/armv7/lowlevel_init.S
+++ b/arch/arm/cpu/armv7/lowlevel_init.S
@@ -17,7 +17,7 @@
 
 ENTRY(lowlevel_init)
        /*
-        * Setup a temporary stack
+        * Setup a temporary stack. Global data is not available yet.
         */
 #ifndef CONFIG_SPL_BUILD
        ldr     sp, =CONFIG_SYS_INIT_SP_ADDR
@@ -25,12 +25,20 @@ ENTRY(lowlevel_init)
        ldr     sp, =CONFIG_SPL_STACK
 #endif
        bic     sp, sp, #7 /* 8-byte alignment for ABI compliance */
+#ifdef CONFIG_DM
+       mov     r9, #0
+#else
+       /*
+        * Set up global data for boards that still need it. This will be
+        * removed soon.
+        */
 #ifdef CONFIG_SPL_BUILD
        ldr     r9, =gdata
 #else
        sub     sp, sp, #GD_SIZE
        bic     sp, sp, #7
        mov     r9, sp
+#endif
 #endif
        /*
         * Save the old lr(passed in ip) and the current lr to stack
@@ -38,7 +46,17 @@ ENTRY(lowlevel_init)
        push    {ip, lr}
 
        /*
-        * go setup pll, mux, memory
+        * Call the very early init function. This should do only the
+        * absolute bare minimum to get started. It should not:
+        *
+        * - set up DRAM
+        * - use global_data
+        * - clear BSS
+        * - try to start a console
+        *
+        * For boards with SPL this should be empty since SPL can do all of
+        * this init in the SPL board_init_f() function which is called
+        * immediately after this.
         */
        bl      s_init
        pop     {ip, pc}