From a70c7bf862f6b4e31375ada8eb39c6535bed6eb4 Mon Sep 17 00:00:00 2001
From: Dave Chapman <dave@dchapman.com>
Date: Mon, 12 Oct 2009 19:46:45 +0000
Subject: Nano2G bootloader - fix dual-booting the Apple firmware.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23139 a1c6a512-1295-4272-9138-f99709370657
---
 bootloader/ipodnano2g.c              | 21 +++++++++++++--------
 firmware/target/arm/s5l8700/boot.lds |  3 +--
 firmware/target/arm/s5l8700/crt0.S   |  2 +-
 3 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/bootloader/ipodnano2g.c b/bootloader/ipodnano2g.c
index 9891ea801e..020da207bd 100644
--- a/bootloader/ipodnano2g.c
+++ b/bootloader/ipodnano2g.c
@@ -51,8 +51,8 @@
 */
 #define MAX_LOADSIZE (8*1024*1024)
 
-/* The buffer to load the firmware into */
-unsigned char *loadbuffer = (unsigned char *)0x08000000;
+/* The buffer to load the firmware into - use an uncached alias of 0x08000000 */
+unsigned char *loadbuffer = (unsigned char *)0x48000000;
 
 /* Bootloader version */
 char version[] = APPSVERSION;
@@ -229,11 +229,9 @@ void main(void)
     if (button_was_held || (btn==BUTTON_MENU)) {
         /* If either the hold switch was on, or the Menu button was held, then 
            try the Apple firmware */
-
-        verbose = true;
         printf("Loading original firmware...");
 
-        if ((rc = readfw("DNANkbso", (void*)0x08000000, &size)) < 0) {
+        if ((rc = readfw("DNANkbso", loadbuffer, &size)) < 0) {
             printf("readfw error %d",rc);
             fatal_error();
         }
@@ -241,7 +239,7 @@ void main(void)
         /* Now we need to decrypt it */
         printf("Decrypting %d bytes...",size);
 
-        aes_decrypt((void*)0x08000000, size);
+        aes_decrypt(loadbuffer, size);
     } else {
         printf("Loading Rockbox...");
         rc=load_firmware(loadbuffer, BOOTFILE, MAX_LOADSIZE);
@@ -265,8 +263,15 @@ void main(void)
     /* Remap the bootrom back to zero - that's how the NOR bootloader leaves
        it.
      */
-    // This won't work, as we are running from IRAM mapped to 0x0...
-    //MIUCON &= ~1;
+    MIUCON &= ~1;
+
+    /* Disable caches and protection unit */
+    asm volatile(
+        "mrc 15, 0, r0, c1, c0, 0 \n"
+        "bic r0, r0, #0x1000      \n"
+        "bic r0, r0, #0x5         \n"
+        "mcr 15, 0, r0, c1, c0, 0 \n"
+    );
 
     /* Branch to start of DRAM */
     asm volatile("ldr pc, =0x08000000");
diff --git a/firmware/target/arm/s5l8700/boot.lds b/firmware/target/arm/s5l8700/boot.lds
index 637a3a29c1..308a97dca8 100644
--- a/firmware/target/arm/s5l8700/boot.lds
+++ b/firmware/target/arm/s5l8700/boot.lds
@@ -12,11 +12,10 @@ STARTUP(target/arm/s5l8700/crt0.o)
 #define DRAMORIG 0x08000000
 #define DRAMSIZE (MEMORYSIZE * 0x100000)
 
+#define IRAMORIG 0x22000000
 #if CONFIG_CPU==S5L8701
-#define IRAMORIG 0x0
 #define IRAMSIZE 176K
 #else
-#define IRAMORIG 0x22000000
 #define IRAMSIZE 256K
 #endif
 
diff --git a/firmware/target/arm/s5l8700/crt0.S b/firmware/target/arm/s5l8700/crt0.S
index 3cc376711c..98f98a3178 100644
--- a/firmware/target/arm/s5l8700/crt0.S
+++ b/firmware/target/arm/s5l8700/crt0.S
@@ -91,7 +91,7 @@ newstart2:
 #ifdef BOOTLOADER
     /* Relocate ourself to IRAM - we have been loaded to DRAM */
     mov    r0, #0x08000000   /* source (DRAM) */
-    mov    r1, #0x00000000   /* dest (IRAM) */
+    mov    r1, #0x22000000   /* dest (IRAM) */
     ldr    r2, =_dataend
 1:
     cmp    r2, r1
-- 
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