Rework linker scripts.

Having separate linker scripts for all the boards is a bad idea. Most
boards really only need to specify MEMORY and the appropriate
REGION_ALIASES() so that support/ld/common.inc can do its work. Not
having infrastructure for this leads to duplication -- viz. the Maple
Mini linker scripts are identical to the Maple's, and the
olimex_stm32_h103 linker directory is just a symlink to
Maple's. Clearly, the current structure is wrong.

To fix it, instead of having per-board subdirectories of support/ld/,
add per-MEMORY subdirectories of (new) support/ld/stm32/mem/. The
per-board .mk files under support/mk/board-includes/ now reference
these directly, and target-config.mk and the Makefile handle this
appropriately. We move some other stuff around in target-config.mk to
make this all more convenient, and even allow more overriding of the
libmaple defaults on a per-board basis. Custom board hacks will be
easier now.

Unfortunately, lots of duplication under support/ld/stm32/mem/ is
necessary, as the LENGTH attribute in a MEMORY region specification
doesn't support arithmetic expressions, and ld doesn't seem to have
any way to specify MEMORY at the command line (why?!). If we find a
better way than this, we should do it.

If a board (e.g. Maple Native) _does_ really need special
memory-related configuration, you can always put a per-board
subdirectory of support/ld/stm32/mem. We do this here to configure the
heap.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

1 files changed, 27 insertions, 24 deletions

diff --git a/support/make/target-config.mk b/support/make/target-config.mk
index a04ca38..ea5dfd9 100644
--- a/support/make/target-config.mk
+++ b/support/make/target-config.mk
@@ -1,39 +1,42 @@
 # TARGET_FLAGS are to be passed while compiling, assembling, linking.
-
 TARGET_FLAGS :=
+# TARGET_LDFLAGS go to the linker
+TARGET_LDFLAGS :=
 
-# Board-specific configuration values. Punt these to board-specific
-# include files.
+# Configuration derived from $(MEMORY_TARGET)
 
-include $(BOARD_INCLUDE_DIR)/$(BOARD).mk
+LD_SCRIPT_PATH := $(LDDIR)/$(MEMORY_TARGET).ld
 
-TARGET_FLAGS += -DBOARD_$(BOARD) -DMCU_$(MCU) \
-                -DERROR_LED_PORT=$(ERROR_LED_PORT) \
-                -DERROR_LED_PIN=$(ERROR_LED_PIN)
+ifeq ($(MEMORY_TARGET), ram)
+VECT_BASE_ADDR := VECT_TAB_RAM
+endif
+ifeq ($(MEMORY_TARGET), flash)
+VECT_BASE_ADDR := VECT_TAB_FLASH
+endif
+ifeq ($(MEMORY_TARGET), jtag)
+VECT_BASE_ADDR := VECT_TAB_BASE
+endif
+
+# Pull in the board configuration file here, so it can override the
+# above.
+
+include $(BOARD_INCLUDE_DIR)/$(BOARD).mk
 
-# STM32 series-specific configuration values.
+# Configuration derived from $(BOARD).mk
 
 LD_SERIES_PATH := $(LDDIR)/stm32/series/$(MCU_SERIES)
+LD_MEM_PATH := $(LDDIR)/stm32/mem/$(LD_MEM_DIR)
 ifeq ($(MCU_SERIES), stm32f1)
 # Due to the Balkanization on F1, we need to specify the line when
 # making linker decisions.
 LD_SERIES_PATH := $(LD_SERIES_PATH)/$(MCU_F1_LINE)
 endif
-LIBMAPLE_MODULE_SERIES := $(LIBMAPLE_PATH)/$(MCU_SERIES)
-
-# Memory target-specific configuration values
 
-ifeq ($(MEMORY_TARGET), ram)
-   LDSCRIPT := $(BOARD)/ram.ld
-   VECT_BASE_ADDR := VECT_TAB_RAM
-endif
-ifeq ($(MEMORY_TARGET), flash)
-   LDSCRIPT := $(BOARD)/flash.ld
-   VECT_BASE_ADDR := VECT_TAB_FLASH
-endif
-ifeq ($(MEMORY_TARGET), jtag)
-   LDSCRIPT := $(BOARD)/jtag.ld
-   VECT_BASE_ADDR := VECT_TAB_BASE
-endif
+TARGET_LDFLAGS += -T$(LD_SCRIPT_PATH) -L $(LD_SERIES_PATH) \
+	          -L $(LD_MEM_PATH) -L$(LDDIR)
+TARGET_FLAGS += -DBOARD_$(BOARD) -DMCU_$(MCU) \
+                -DERROR_LED_PORT=$(ERROR_LED_PORT) \
+                -DERROR_LED_PIN=$(ERROR_LED_PIN) \
+                -D$(VECT_BASE_ADDR)
 
-TARGET_FLAGS += -D$(VECT_BASE_ADDR)
+LIBMAPLE_MODULE_SERIES := $(LIBMAPLE_PATH)/$(MCU_SERIES)