rk27xx: Implement HAVE_INIT_ATTR magic

This reclaims over 7kB of ram.

Change-Id: I4a89c9a673ada7959311f320900060f6db303c07

firmware/export/config.h

@@ -981,7 +981,8 @@ Lyre prototype 1 */
 #endif
 
 #if (defined(CPU_PP) || (CONFIG_CPU == AS3525) || (CONFIG_CPU == AS3525v2) || \
-    (CONFIG_CPU == IMX31L) || (CONFIG_CPU == IMX233)) \
+    (CONFIG_CPU == IMX31L) || (CONFIG_CPU == IMX233) || \
+    (CONFIG_CPU == RK27XX)) \
     && (CONFIG_PLATFORM & PLATFORM_NATIVE) && !defined(BOOTLOADER)
 /* Functions that have INIT_ATTR attached are NOT guaranteed to survive after
  * root_menu() has been called. Their code may be overwritten by other data or

firmware/target/arm/rk27xx/app.lds

@@ -22,6 +22,10 @@ STARTUP(target/arm/rk27xx/crt0.o)
 #define ENDAUDIOADDR  (DRAMORIG + DRAMSIZE)
 #define CODECORIG (ENDAUDIOADDR)
 
+/* .init is copied to codec buffer */
+#define INITORIG CODECORIG
+#define INITSIZE CODECSIZE
+
 /* Where the codec buffer ends, and the plugin buffer starts */
 #define ENDADDR (ENDAUDIOADDR + CODECSIZE)
 
@@ -29,21 +33,14 @@ MEMORY
 {
     DRAM  : ORIGIN = DRAMORIG, LENGTH = DRAMSIZE
     IRAM  : ORIGIN = IRAMORIG, LENGTH = IRAMSIZE
+    INIT  : ORIGIN = INITORIG, LENGTH = INITSIZE
 }
 
 SECTIONS
 {
   loadaddress = DRAMORIG;
 
-  .intvect : {
-    _intvectstart = . ;
-    KEEP(*(.intvect))
-    _intvectend = . ;  
-  } > IRAM AT > DRAM
-  _intvectcopy = LOADADDR(.intvect);
-
   .text : {
-    *(.init.text)
     *(.text*)
     *(.icode*)
     *(.glue_7*)
@@ -61,7 +58,27 @@ SECTIONS
     . = ALIGN(0x4);
   } > DRAM
 
-  .stack (NOLOAD) :
+  /* NOLOAD sections at end start here. Any part of the binary image past
+   * this point is discarded or copied elsewhere. */
+  _noloaddram = .;
+
+  .intvect : {
+    _intvectstart = . ;
+    KEEP(*(.intvect))
+    _intvectend = . ;
+  } > IRAM AT > DRAM
+  _intvectcopy = LOADADDR(.intvect);
+  
+  .init : {
+    . = ALIGN(4);
+    _initstart = .;
+    *(.init*)
+    *(.initdata*)
+    _initend = .;
+  } > INIT AT > DRAM
+  _initcopy = LOADADDR(.init);
+
+  .stack _noloaddram (NOLOAD) :
   {
      *(.stack)
      _stackbegin = .;

firmware/target/arm/rk27xx/crt0.S

@@ -149,6 +149,20 @@ entry_point:
     strhi   r1, [r2], #4
     bhi     1b
 
+#ifdef HAVE_INIT_ATTR
+    /* Copy init section to the codec buffer
+     * before .bss zeroing
+     */
+    ldr     r2, =_initstart
+    ldr     r3, =_initend
+    ldr     r4, =_initcopy
+1:
+    cmp     r3, r2
+    ldrhi   r1, [r4], #4
+    strhi   r1, [r2], #4
+    bhi     1b
+#endif
+
     /* Initialise bss, ibss section to zero */
     ldr     r2, =_edata
     ldr     r3, =_end