rockchip: boot0 hook: support early return for RK3188/RK3066-style BROM

[u-boot] / arch / arm / include / asm / arch-rockchip / boot0.h

diff --git a/arch/arm/include/asm/arch-rockchip/boot0.h b/arch/arm/include/asm/arch-rockchip/boot0.h
index f7c614669cf7716fa0444a0c97d5d8c17d9018e8..af3a733e98443a8c3aead6c22e69ab48dcc67ae9 100644 (file)
--- a/arch/arm/include/asm/arch-rockchip/boot0.h
+++ b/arch/arm/include/asm/arch-rockchip/boot0.h
@@ -19,12 +19,25 @@
         * beginning of the executable.  However, as we want to keep
         * this generic and make it applicable to builds that are like
         * the RK3368 (TPL needs this, SPL doesn't) or the RK3399 (no
-        * TPL, but extra space needed in the SPL), we simply repeat
-        * the 'b reset' with the expectation that the first one will
-        * be overwritten, if this is the first stage contained in the
-        * final image created with mkimage)...
+        * TPL, but extra space needed in the SPL), we simply insert
+        * a branch-to-next-instruction-word with the expectation that
+        * the first one may be overwritten, if this is the first stage
+        * contained in the final image created with mkimage)...
         */
-       b reset  /* may be overwritten --- should be 'nop' or a 'b reset' */
+       b 1f     /* if overwritten, entry-address is at the next word */
+1:
+#endif
+#if CONFIG_IS_ENABLED(ROCKCHIP_EARLYRETURN_TO_BROM)
+       adr     r3, entry_counter
+       ldr     r0, [r3]
+       cmp     r0, #1           /* check if entry_counter == 1 */
+       beq     reset            /* regular bootup */
+       add     r0, #1
+       str     r0, [r3]         /* increment the entry_counter in memory */
+       mov     r0, #0           /* return 0 to the BROM to signal 'OK' */
+       bx      lr               /* return control to the BROM */
+entry_counter:
+       .word   0
 #endif
        b reset
 #if !defined(CONFIG_ARM64)
@@ -32,7 +45,7 @@
         * For armv7, the addr '_start' will used as vector start address
         * and write to VBAR register, which needs to aligned to 0x20.
         */
-       .align(5)
+       .align(5), 0x0
 _start:
        ARM_VECTORS
 #endif