Move this section of the README into doc/ with some minor updates to
mention SPL and user lower-case hex.
Signed-off-by: Simon Glass <s...@chromium.org>
---
Changes in v2:
- Mention that these docs need updating
README | 45 ----------------------------------------
doc/develop/index.rst | 1 +
doc/develop/memory.rst | 47 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 48 insertions(+), 45 deletions(-)
create mode 100644 doc/develop/memory.rst
diff --git a/README b/README
index 4be1e8c22a0..d73042406b6 100644
--- a/README
+++ b/README
@@ -2516,51 +2516,6 @@ On RISC-V, the following registers are used:
==> U-Boot will use gp to hold a pointer to the global data
-Memory Management:
-------------------
-
-U-Boot runs in system state and uses physical addresses, i.e. the
-MMU is not used either for address mapping nor for memory protection.
-
-The available memory is mapped to fixed addresses using the memory
-controller. In this process, a contiguous block is formed for each
-memory type (Flash, SDRAM, SRAM), even when it consists of several
-physical memory banks.
-
-U-Boot is installed in the first 128 kB of the first Flash bank (on
-TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After
-booting and sizing and initializing DRAM, the code relocates itself
-to the upper end of DRAM. Immediately below the U-Boot code some
-memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
-configuration setting]. Below that, a structure with global Board
-Info data is placed, followed by the stack (growing downward).
-
-Additionally, some exception handler code is copied to the low 8 kB
-of DRAM (0x00000000 ... 0x00001FFF).
-
-So a typical memory configuration with 16 MB of DRAM could look like
-this:
-
- 0x0000 0000 Exception Vector code
- :
- 0x0000 1FFF
- 0x0000 2000 Free for Application Use
- :
- :
-
- :
- :
- 0x00FB FF20 Monitor Stack (Growing downward)
- 0x00FB FFAC Board Info Data and permanent copy of global data
- 0x00FC 0000 Malloc Arena
- :
- 0x00FD FFFF
- 0x00FE 0000 RAM Copy of Monitor Code
- ... eventually: LCD or video framebuffer
- ... eventually: pRAM (Protected RAM - unchanged by reset)
- 0x00FF FFFF [End of RAM]
-
-
System Initialization:
----------------------
diff --git a/doc/develop/index.rst b/doc/develop/index.rst
index 0d0e60ab56c..cbea38d4323 100644
--- a/doc/develop/index.rst
+++ b/doc/develop/index.rst
@@ -13,6 +13,7 @@ General
codingstyle
designprinciples
docstyle
+ memory
patman
process
release_cycle
diff --git a/doc/develop/memory.rst b/doc/develop/memory.rst
new file mode 100644
index 00000000000..816fe3ec5db
--- /dev/null
+++ b/doc/develop/memory.rst
@@ -0,0 +1,47 @@
+.. SPDX-License-Identifier: GPL-2.0+:
+
+Memory Management
+-----------------
+
+Note: This information is outdated and needs to be updated.
+
+U-Boot runs in system state and uses physical addresses, i.e. the
+MMU is not used either for address mapping nor for memory protection.
+
+The available memory is mapped to fixed addresses using the
+memory-controller. In this process, a contiguous block is formed for each
+memory type (Flash, SDRAM, SRAM), even when it consists of several
+physical-memory banks.
+
+U-Boot is installed in XIP flash memory, or may be loaded into a lower region
of
+RAM by a secondary program loader (SPL). After
+booting and sizing and initialising DRAM, the code relocates itself
+to the upper end of DRAM. Immediately below the U-Boot code some
+memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN
+configuration setting]. Below that, a structure with global Board-Info
+data is placed, followed by the stack (growing downward).
+
+Additionally, some exception handler code may be copied to the low 8 kB
+of DRAM (0x00000000 ... 0x00001fff).
+
+So a typical memory configuration with 16 MB of DRAM could look like
+this::
+
+ 0x0000 0000 Exception Vector code
+ :
+ 0x0000 1fff
+ 0x0000 2000 Free for Application Use
+ :
+ :
+
+ :
+ :
+ 0x00fb ff20 Monitor Stack (Growing downward)
+ 0x00fb ffac Board Info Data and permanent copy of global data
+ 0x00fc 0000 Malloc Arena
+ :
+ 0x00fd ffff
+ 0x00fe 0000 RAM Copy of Monitor Code
+ ... eventually: LCD or video framebuffer
+ ... eventually: pRAM (Protected RAM - unchanged by reset)
+ 0x00ff ffff [End of RAM]
--
2.43.0
