multiboot: Add v1 boot protocol

v1 passes the drive and partition number of the boot volume
instead of using the volume number. The volume number isn't
reliable because the same filesystem might get a different
volume number once the firmware is loaded, which will cause
the firmware to use the wrong root volume and fail to locate
the correct .rockbox directory.

Using drive and partition numbers avoids this issue because
drive numbering is fixed and determined by the target.

Change-Id: I7e68b892d9424a1f686197a6122e139b438e5f7e

1 files changed, 14 insertions, 1 deletions

diff --git a/firmware/common/multiboot.c b/firmware/common/multiboot.c
index c292aa1c30..8d6573d2dd 100644
--- a/firmware/common/multiboot.c
+++ b/firmware/common/multiboot.c
@@ -23,6 +23,7 @@
 #include "crc32.h"
 #include "loader_strerror.h"
 #include "file.h"
+#include "disk.h"
 #include <string.h>
 #include <stdio.h>
 
@@ -30,10 +31,20 @@ static void write_bootdata_v0(struct boot_data_t *data, unsigned int boot_volume
 {
     memset(data->payload, data->length, 0);
 
-    data->boot_volume = boot_volume;
+    data->_boot_volume = boot_volume;
     data->version = 0;
 }
 
+static void write_bootdata_v1(struct boot_data_t *data, unsigned int boot_volume)
+{
+    memset(data->payload, data->length, 0);
+
+    data->_boot_volume = 0xff;
+    data->version = 1;
+    data->boot_drive = volume_drive(boot_volume);
+    data->boot_partition = volume_partition(boot_volume);
+}
+
 /* Write bootdata into location in FIRMWARE marked by magic header
  * Assumes buffer is already loaded with the firmware image
  * We just need to find the location and write data into the
@@ -68,6 +79,8 @@ bool write_bootdata(unsigned char* buf, int len, unsigned int boot_volume)
         /* Write boot data according to the selected protocol */
         if (proto_version == 0)
             write_bootdata_v0(data, boot_volume);
+        else if (proto_version == 1)
+            write_bootdata_v1(data, boot_volume);
         else
             break;