Merge pull request #1328 from JiafeiPan/upstream-bl2-rom

Add support for BL2 in XIP memory

2 files changed, 33 insertions, 1 deletions

diff --git a/docs/porting-guide.rst b/docs/porting-guide.rst
index ff5bb1225..12e135f71 100644
--- a/docs/porting-guide.rst
+++ b/docs/porting-guide.rst
@@ -217,11 +217,37 @@ platform port to define additional platform porting constants in
 -  **#define : BL2\_BASE**
 
    Defines the base address in secure RAM where BL1 loads the BL2 binary image.
-   Must be aligned on a page-size boundary.
+   Must be aligned on a page-size boundary. This constant is not applicable
+   when BL2_IN_XIP_MEM is set to '1'.
 
 -  **#define : BL2\_LIMIT**
 
    Defines the maximum address in secure RAM that the BL2 image can occupy.
+   This constant is not applicable when BL2_IN_XIP_MEM is set to '1'.
+
+-  **#define : BL2\_RO\_BASE**
+
+   Defines the base address in secure XIP memory where BL2 RO section originally
+   lives. Must be aligned on a page-size boundary. This constant is only needed
+   when BL2_IN_XIP_MEM is set to '1'.
+
+-  **#define : BL2\_RO\_LIMIT**
+
+   Defines the maximum address in secure XIP memory that BL2's actual content
+   (i.e. excluding any data section allocated at runtime) can occupy. This
+   constant is only needed when BL2_IN_XIP_MEM is set to '1'.
+
+-  **#define : BL2\_RW\_BASE**
+
+   Defines the base address in secure RAM where BL2's read-write data will live
+   at runtime. Must be aligned on a page-size boundary. This constant is only
+   needed when BL2_IN_XIP_MEM is set to '1'.
+
+-  **#define : BL2\_RW\_LIMIT**
+
+   Defines the maximum address in secure RAM that BL2's read-write data can
+   occupy at runtime. This constant is only needed when BL2_IN_XIP_MEM is set
+   to '1'.
 
 -  **#define : BL31\_BASE**
 
diff --git a/docs/user-guide.rst b/docs/user-guide.rst
index 579485546..fdf1568e1 100644
--- a/docs/user-guide.rst
+++ b/docs/user-guide.rst
@@ -246,6 +246,12 @@ Common build options
 - ``BL2_AT_EL3``: This is an optional build option that enables the use of
    BL2 at EL3 execution level.
 
+- ``BL2_IN_XIP_MEM``: In some use-cases BL2 will be stored in eXecute In Place
+   (XIP) memory, like BL1. In these use-cases, it is necessary to initialize
+   the RW sections in RAM, while leaving the RO sections in place. This option
+   enable this use-case. For now, this option is only supported when BL2_AT_EL3
+   is set to '1'.
+
 -  ``BL31``: This is an optional build option which specifies the path to
    BL31 image for the ``fip`` target. In this case, the BL31 in TF-A will not
    be built.