cpu/cc2538: add riotboot

Flash Customer Configuration Area (CCA) is never written when the
riotboot module is used. This required a riot application to have
been previously flashed. riotboot will completely ignore this
section, neither writing or erasing it.

Slot flashing is currenly only supported with Jlink.

Co-authored-by: Brenton Chetty <brent7984@gmail.com>

cpu/cc2538/Kconfig

@@ -8,6 +8,7 @@
 config CPU_FAM_CC2538
     bool
     select CPU_CORE_CORTEX_M3
+    select HAS_CORTEXM_MPU
     select HAS_CPU_CC2538
     select HAS_PERIPH_CPUID
     select HAS_PERIPH_FLASHPAGE
@@ -17,7 +18,7 @@ config CPU_FAM_CC2538
     select HAS_PERIPH_HWRNG
     select HAS_PERIPH_UART_MODECFG
     select HAS_PERIPH_WDT
-    select HAS_CORTEXM_MPU
+    select HAS_RIOTBOOT
 
 ## CPU Models
 config CPU_MODEL_CC2538NF53

cpu/cc2538/Makefile.features

@@ -10,5 +10,6 @@ FEATURES_PROVIDED += periph_uart_modecfg
 FEATURES_PROVIDED += periph_wdt
 
 FEATURES_PROVIDED += cortexm_mpu
+FEATURES_PROVIDED += riotboot
 
 include $(RIOTCPU)/cortexm_common/Makefile.features

cpu/cc2538/Makefile.include

@@ -1,4 +1,7 @@
 
+# Strip 'K' from ROM_LEN definition
+_rom_len_k = $(shell echo $1 | sed 's/K//')
+
 # Set ROM and RAM lengths according to CPU model
 ifneq (,$(filter cc2538nf11,$(CPU_MODEL)))
   ROM_LEN ?= 128K
@@ -13,14 +16,31 @@ ifneq (,$(filter cc2538nf53 cc2538sf53,$(CPU_MODEL)))
   RAM_LEN ?= 32K
 endif
 
+# If using riotboot subtract 2 pages (2 * 2K) to not write over CCA
+# section and keep page parity (so slots are split evenly among pages)
+ifneq (,$(filter riotboot,$(FEATURES_USED)))
+  ROM_LEN := $(shell echo $$(( $(call _rom_len_k,$(ROM_LEN)) - 4 )) )K
+endif
+
+# Set ROM and RAM start address
 ROM_START_ADDR ?= 0x00200000
 RAM_START_ADDR ?= 0x20000000
 
-KB := 1024
-ROM_LEN_K := $(shell echo $(ROM_LEN) | sed 's/K//')
-FLASHSIZE := $(shell echo $$(( $(ROM_LEN_K) * $(KB) )) )
-
 # Set CFLAGS
+KB := 1024
+FLASHSIZE := $(shell echo $$(( $(call _rom_len_k,$(ROM_LEN)) * $(KB))) )
 CFLAGS += -DCC2538_FLASHSIZE=$(FLASHSIZE)U
 
+# Use common ld script
+LINKER_SCRIPT ?= cc2538.ld
+
+# The entry point `cortex_vector_base` is defined in the cca field.
+# If the cca field is updated when flashing a slot then the entry
+# point will never be the bootloader but the respective slot. This
+# ensures it never happens, the last page will never be touched when
+# using riotboot.
+ifneq (,$(filter riotboot,$(FEATURES_USED)))
+  CFLAGS += -DUPDATE_CCA=0
+endif
+
 include $(RIOTMAKE)/arch/cortexm.inc.mk

cpu/cc2538/include/cpu_conf.h

@@ -19,6 +19,7 @@
 #ifndef CPU_CONF_H
 #define CPU_CONF_H
 
+#include "kernel_defines.h"
 #include "cpu_conf_common.h"
 #include "cc2538.h"
 #include "cc2538_gpio.h"
@@ -56,7 +57,7 @@ extern "C" {
 #ifndef FLASHPAGE_CC2538_USE_CCA_PAGE
 #define FLASHPAGE_CC2538_USE_CCA_PAGE   (0)
 #endif
-#if FLASHPAGE_CC2538_USE_CCA_PAGE
+#if (IS_ACTIVE(MODULE_RIOTBOOT) || FLASHPAGE_CC2538_USE_CCA_PAGE)
 #define FLASHPAGE_NUMOF         ((CC2538_FLASHSIZE / FLASHPAGE_SIZE))
 #else
 #define FLASHPAGE_NUMOF         ((CC2538_FLASHSIZE / FLASHPAGE_SIZE) -1)

cpu/cc2538/ldscripts/cc2538.ld

@@ -16,12 +16,16 @@
  * @author          Hauke Petersen <hauke.petersen@fu-berlin.de>
  */
 
+INCLUDE cortexm_rom_offset.ld
+
 /* Memory Space Definitions: */
 MEMORY
 {
-    rom (rx)    : ORIGIN = 0x00200000, LENGTH = 512K - 44
+    rom (rx)    : ORIGIN = _rom_start_addr + _rom_offset, LENGTH = _fw_rom_length
     cca         : ORIGIN = 0x0027ffd4, LENGTH = 44
-    ram (w!rx)  : ORIGIN = 0x20000000, LENGTH = 32K
+    sram0       : ORIGIN = 0x20000000, LENGTH = 16K /* Lost in PM2 and PM3 */
+    sram1       : ORIGIN = 0x20004000, LENGTH = 16K
+    ram (w!rx)  : ORIGIN = _ram_start_addr, LENGTH = _ram_length
 }
 
 /* MCU Specific Section Definitions */

cpu/cc2538/ldscripts/cc2538nf11.ld

@@ -1,39 +0,0 @@
-/*
- * Copyright (C) 2014 Loci Controls Inc.
- *
- * This file is subject to the terms and conditions of the GNU Lesser
- * General Public License v2.1. See the file LICENSE in the top level
- * directory for more details.
- */
-
-/**
- * @addtogroup      cpu_cc2538
- * @{
- *
- * @file
- * @brief           Linker script for the CC2538NF11 model MCU
- *
- * @author          Ian Martin <ian@locicontrols.com>
- */
-
-/* Memory Space Definitions: */
-MEMORY
-{
-    rom (rx)    : ORIGIN = 0x00200000, LENGTH = 128K - 44
-    cca         : ORIGIN = 0x0027ffd4, LENGTH = 44
-    sram1       : ORIGIN = 0x20004000, LENGTH = 16K
-    ram (w!rx)  : ORIGIN = 0x20004000, LENGTH = 16K
-}
-
-/* MCU Specific Section Definitions */
-SECTIONS
-{
-    .flashcca :
-    {
-        KEEP(*(.flashcca))
-    } > cca
-}
-
-INCLUDE cortexm_base.ld
-
-/* @} */

cpu/cc2538/ldscripts/cc2538nf23.ld

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2014 Loci Controls Inc.
- *
- * This file is subject to the terms and conditions of the GNU Lesser
- * General Public License v2.1. See the file LICENSE in the top level
- * directory for more details.
- */
-
-/**
- * @addtogroup      cpu_cc2538
- * @{
- *
- * @file
- * @brief           Linker script for the CC2538NF23 and CC2538SF23 model MCUs
- *
- * @author          Ian Martin <ian@locicontrols.com>
- */
-
-/* Memory Space Definitions: */
-MEMORY
-{
-    rom (rx)    : ORIGIN = 0x00200000, LENGTH = 256K - 44
-    cca         : ORIGIN = 0x0027ffd4, LENGTH = 44
-    sram0       : ORIGIN = 0x20000000, LENGTH = 16K /* Lost in PM2 and PM3 */
-    sram1       : ORIGIN = 0x20004000, LENGTH = 16K
-    ram (w!rx)  : ORIGIN = 0x20000000, LENGTH = 32K
-}
-
-/* MCU Specific Section Definitions */
-SECTIONS
-{
-    .flashcca :
-    {
-        KEEP(*(.flashcca))
-    } > cca
-}
-
-INCLUDE cortexm_base.ld
-
-/* @} */

cpu/cc2538/ldscripts/cc2538nf53.ld

@@ -1,40 +0,0 @@
-/*
- * Copyright (C) 2014 Loci Controls Inc.
- *
- * This file is subject to the terms and conditions of the GNU Lesser
- * General Public License v2.1. See the file LICENSE in the top level
- * directory for more details.
- */
-
-/**
- * @addtogroup      cpu_cc2538
- * @{
- *
- * @file
- * @brief           Linker script for the CC2538NF53 and CC2538SF53 model MCUs
- *
- * @author          Ian Martin <ian@locicontrols.com>
- */
-
-/* Memory Space Definitions: */
-MEMORY
-{
-    rom (rx)    : ORIGIN = 0x00200000, LENGTH = 512K - 44
-    cca         : ORIGIN = 0x0027ffd4, LENGTH = 44
-    sram0       : ORIGIN = 0x20000000, LENGTH = 16K /* Lost in PM2 and PM3 */
-    sram1       : ORIGIN = 0x20004000, LENGTH = 16K
-    ram (w!rx)  : ORIGIN = 0x20000000, LENGTH = 32K
-}
-
-/* MCU Specific Section Definitions */
-SECTIONS
-{
-    .flashcca :
-    {
-        KEEP(*(.flashcca))
-    } > cca
-}
-
-INCLUDE cortexm_base.ld
-
-/* @} */