From 58be5a5aa328e687a3560d4a85fb069400b0b8ca Mon Sep 17 00:00:00 2001
From: Damien George <damien@micropython.org>
Date: Wed, 28 Apr 2021 16:26:20 +1000
Subject: [PATCH] stm32/mboot: Allow a board to customise the linker scripts.

A board can now define MBOOT_LD_FILES (at the Makefile-level) to specify
custom linker scripts.  And stm32_generic.ld has been split into 2 pieces
so one or the other can be reused (usually stm32_sections.ld wolud be
reused by a board, and stm32_memory.ld redefined).

Signed-off-by: Damien George <damien@micropython.org>
---
 ports/stm32/mboot/Makefile                             |  3 ++-
 ports/stm32/mboot/stm32_memory.ld                      | 10 ++++++++++
 .../mboot/{stm32_generic.ld => stm32_sections.ld}      | 10 ++--------
 3 files changed, 14 insertions(+), 9 deletions(-)
 create mode 100644 ports/stm32/mboot/stm32_memory.ld
 rename ports/stm32/mboot/{stm32_generic.ld => stm32_sections.ld} (87%)

diff --git a/ports/stm32/mboot/Makefile b/ports/stm32/mboot/Makefile
index d57b9368e..de090da1c 100755
--- a/ports/stm32/mboot/Makefile
+++ b/ports/stm32/mboot/Makefile
@@ -85,7 +85,8 @@ CFLAGS += -DBUILDING_MBOOT=$(BUILDING_MBOOT)
 CFLAGS += -DMICROPY_HW_STM32WB_FLASH_SYNCRONISATION=0
 CFLAGS += -DBOOTLOADER_DFU_USB_VID=$(BOOTLOADER_DFU_USB_VID) -DBOOTLOADER_DFU_USB_PID=$(BOOTLOADER_DFU_USB_PID)
 
-LDFLAGS = -nostdlib -L . -T stm32_generic.ld -Map=$(@:.elf=.map) --cref
+MBOOT_LD_FILES ?= stm32_memory.ld stm32_sections.ld
+LDFLAGS = -nostdlib -L . $(addprefix -T,$(MBOOT_LD_FILES)) -Map=$(@:.elf=.map) --cref
 LIBS = $(shell $(CC) $(CFLAGS) -print-libgcc-file-name)
 
 # Remove uncalled code from the final image.
diff --git a/ports/stm32/mboot/stm32_memory.ld b/ports/stm32/mboot/stm32_memory.ld
new file mode 100644
index 000000000..cfcac4096
--- /dev/null
+++ b/ports/stm32/mboot/stm32_memory.ld
@@ -0,0 +1,10 @@
+/*
+    Linker script fragment for mboot on an STM32xxx MCU.
+    This defines the memory sections for the bootloader to use.
+*/
+
+MEMORY
+{
+    FLASH_BL (rx)   : ORIGIN = 0x08000000, LENGTH = 32K
+    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 120K
+}
diff --git a/ports/stm32/mboot/stm32_generic.ld b/ports/stm32/mboot/stm32_sections.ld
similarity index 87%
rename from ports/stm32/mboot/stm32_generic.ld
rename to ports/stm32/mboot/stm32_sections.ld
index ade434967..3302c5f97 100644
--- a/ports/stm32/mboot/stm32_generic.ld
+++ b/ports/stm32/mboot/stm32_sections.ld
@@ -1,14 +1,8 @@
 /*
-    GNU linker script for generic STM32xxx MCU
+    Linker script fragment for mboot on an STM32xxx MCU.
+    This needs the following MEMORY sections to be defined: FLASH_BL, RAM.
 */
 
-/* Specify the memory areas */
-MEMORY
-{
-    FLASH_BL (rx)   : ORIGIN = 0x08000000, LENGTH = 32K /* sector 0 (can be 32K) */
-    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 120K
-}
-
 /* produce a link error if there is not this amount of RAM for these sections */
 _minimum_stack_size = 8K;