altoslib: Linker script changed -> the USB desc is two bytes off

The USB descriptor used to be at 0x0800110c in previous releases and
is now at 0x0800110a, presumably because the linker script changed the
padding requirements of those sections.

Search forward and backwards two bytes to see if we can't find the
descriptors by checking for the descriptor value and size at each
location.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/altoslib/AltosHexfile.java b/altoslib/AltosHexfile.java
index 609d1bcb366f9f3ae747633f1f0a51e8894d04ad..cf99cded5ade7303fb337b299d2613cfc561021d 100644 (file)
--- a/altoslib/AltosHexfile.java
+++ b/altoslib/AltosHexfile.java
@@ -295,15 +295,20 @@ public class AltosHexfile {
                        return -1;
 
                try {
-                       /* Walk the descriptors looking for the device */
+                       /* The address of this has moved depending on
+                        * padding in the linker script. Look forward
+                        * and backwards two bytes to see if we can find it
+                        */
                        a = usb_descriptors.address;
-                       while (get_u8(a+1) != AO_USB_DESC_DEVICE) {
-                               int delta = get_u8(a);
-                               a += delta;
-                               if (delta == 0 || a >= max_address)
-                                       return -1;
-                       }
-                       return a;
+
+                       if (get_u8(a) == 0x12 && get_u8(a+1) == AO_USB_DESC_DEVICE)
+                               return a;
+                       else if (get_u8(a+1) == 0x12 && get_u8(a+3) == AO_USB_DESC_DEVICE)
+                               return a + 2;
+                       else if (get_u8(a-2) == 0x12 && get_u8(a-1) == AO_USB_DESC_DEVICE)
+                               return a - 2;
+
+                       return -1;
                } catch (ArrayIndexOutOfBoundsException ae) {
                        return -1;
                }