MIPS: set load address of .iram to the start of .bss so RAM doesn't get wasted

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@20741 a1c6a512-1295-4272-9138-f99709370657

firmware/target/mips/ingenic_jz47xx/app.lds

@@ -70,7 +70,10 @@ SECTIONS
     
     . = ALIGN(4);
     
-    .iram IRAMORIG:
+    /* Set the load address of .iram at the same address as .bss
+     * so RAM won't be wasted as .iram in the end will get copied
+     * to IRAM. */
+    .iram IRAMORIG: AT (_edata)
     {
         _iramstart = .;
         *(.vectors.1);
@@ -88,7 +91,7 @@ SECTIONS
         KEEP(*(.vectors))
         *(.vectors);
         _iramend = .;
-    } > IRAM AT> DRAM
+    } > IRAM
     _iramcopy = LOADADDR(.iram);
     
     . = ALIGN(4);

firmware/target/mips/ingenic_jz47xx/crt0.S

@@ -120,6 +120,23 @@ _init_cache_loop:
     mtc0    t0, C0_CONFIG
     nop
     
+    /*
+      ----------------------------------------------------
+       Copy IRAM section
+        * copy IRAM first before BSS gets cleared, as both
+          have the same address
+      ----------------------------------------------------
+    */
+    la     t0, _iramcopy
+    la     t1, _iramstart
+    la     t2, _iramend
+_init_iram_loop:
+    lw     t3, 0(t0)
+    sw     t3, 0(t1)
+    addiu  t1, 4
+    bne    t1, t2, _init_iram_loop
+    addiu  t0, 4
+    
     /*
       ----------------------------------------------------
        Clear BSS section
@@ -143,21 +160,6 @@ _init_ibss_loop:
     sw     zero, 0(t0)
     bne    t0, t1, _init_ibss_loop
     addiu  t0, 4
-    
-    /*
-      ----------------------------------------------------
-       Copy IRAM section
-      ----------------------------------------------------
-    */
-    la     t0, _iramcopy
-    la     t1, _iramstart
-    la     t2, _iramend
-_init_iram_loop:
-    lw     t3, 0(t0)
-    sw     t3, 0(t1)
-    addiu  t1, 4
-    bne    t1, t2, _init_iram_loop
-    addiu  t0, 4
 
     /*
       ----------------------------------------------------