stm32g4: Add basic support

* memorymap
* vectors
* rcc
* gpios
* makefiles
* devices for linker script generation
* doc structure

lib/dispatch/vector_nvic.c

@@ -18,6 +18,8 @@
 #	include "../stm32/l4/vector_nvic.c"
 #elif defined(STM32G0)
 #	include "../stm32/g0/vector_nvic.c"
+#elif defined(STM32G4)
+#	include "../stm32/g4/vector_nvic.c"
 #elif defined(STM32H7)
 #	include "../stm32/h7/vector_nvic.c"
 

lib/stm32/g4/Makefile

@@ -0,0 +1,44 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2020 Karl Palsson <karlp@tweak.net.au>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+LIBNAME		= libopencm3_stm32g4
+SRCLIBDIR	?= ../..
+
+FP_FLAGS	?= -mfloat-abi=hard -mfpu=fpv4-sp-d16
+CC		= $(PREFIX)gcc
+AR		= $(PREFIX)ar
+TGT_CFLAGS	= -Os \
+		  -Wall -Wextra -Wimplicit-function-declaration \
+		  -Wredundant-decls -Wmissing-prototypes -Wstrict-prototypes \
+		  -Wundef -Wshadow \
+		  -I../../../include -fno-common \
+		  -mcpu=cortex-m4 -mthumb $(FP_FLAGS) \
+		  -Wstrict-prototypes \
+		  -ffunction-sections -fdata-sections -MD -DSTM32G4
+TGT_CFLAGS      += $(DEBUG_FLAGS)
+TGT_CFLAGS	+= $(STANDARD_FLAGS)
+ARFLAGS		= rcs
+
+OBJS += gpio_common_all.o gpio_common_f0234.o
+OBJS += rcc_common_all.o
+
+VPATH += ../../usb:../:../../cm3:../common
+VPATH += ../../ethernet
+
+include ../../Makefile.include