Sansa E200v1 Bootloader attempt at enabling USB in boot loader

there is a 1MB free region that is used to load the firmware but we
shouldn't need that till after a USB connection

so here is my 2nd try

Change-Id: I2552db3a7fba019d7e7188984432f758ddafe548

1 files changed, 15 insertions, 4 deletions

diff --git a/firmware/core_alloc.c b/firmware/core_alloc.c
index df1b4d3213..bf2f8e8298 100644
--- a/firmware/core_alloc.c
+++ b/firmware/core_alloc.c
@@ -8,16 +8,27 @@
 /* not static so it can be discovered by core_get_data() */
 struct buflib_context core_ctx;
 
-/* defined in linker script */
 #if (CONFIG_PLATFORM & PLATFORM_NATIVE) && !defined(__PCTOOL__)
+
 #if defined(IPOD_VIDEO) && !defined(BOOTLOADER)
+/* defined in linker script */
+extern unsigned char audiobuffer[];
 extern unsigned char *audiobufend_lds[];
+/* pointer to end of audio buffer filled at runtime allocator_init */
 unsigned char *audiobufend;
-#else /* !IPOD_VIDEO */
-extern unsigned char audiobufend[];
-#endif
+#elif defined(SANSA_E200) && defined(HAVE_BOOTLOADER_USB_MODE)
+/* defined in linker script */
+extern unsigned char freebuffer[];
+extern unsigned char freebufferend[];
+/* map linker symbol to the audiobuffer in order to use core_alloc */
+unsigned char *audiobuffer = (unsigned char *)freebuffer;
+unsigned char *audiobufend = (unsigned char *)freebufferend;
+#else /* !IPOD_VIDEO, !SANSA_E200&&BOOTLOADERUSB */
 /* defined in linker script */
 extern unsigned char audiobuffer[];
+extern unsigned char audiobufend[];
+#endif
+
 #else /* PLATFORM_HOSTED */
 static unsigned char audiobuffer[((MEMORYSIZE)*1024-768)*1024];
 unsigned char *audiobufend = audiobuffer + sizeof(audiobuffer);