stm32f4: write flash using byte access

src/include/general.h

@@ -41,6 +41,8 @@
 #define ALIGN(x, n) (((x) + (n) - 1) & ~((n) - 1))
 #undef MIN
 #define MIN(x, y)  (((x) < (y)) ? (x) : (y))
+#undef MAX
+#define MAX(x, y)  (((x) > (y)) ? (x) : (y))
 
 #endif
 

src/target/flashstub/Makefile

@@ -11,10 +11,12 @@ endif
 CFLAGS=-Os -std=gnu99 -mcpu=cortex-m0 -mthumb -I../../../libopencm3/include
 ASFLAGS=-mcpu=cortex-m3 -mthumb
 
-all:	lmi.stub stm32f4.stub stm32l4.stub nrf51.stub stm32f1.stub efm32.stub
+all:	lmi.stub stm32f4_x8.stub stm32f4_x32.stub stm32l4.stub nrf51.stub \
+	stm32f1.stub efm32.stub
 
 stm32f1.o: CFLAGS += -DSTM32F1
-stm32f4.o: CFLAGS += -DSTM32F4
+stm32f4_x8.o: CFLAGS += -DSTM32F4
+stm32f4_x32.o: CFLAGS += -DSTM32F4
 
 %.o:    %.c
 	$(Q)echo "  CC      $<"

src/target/flashstub/stm32f4_x32.c

@@ -23,7 +23,7 @@
 #define SR_ERROR_MASK 0xF2
 
 void __attribute__((naked))
-stm32f4_flash_write_stub(uint32_t *dest, uint32_t *src, uint32_t size)
+stm32f4_flash_write_x32_stub(uint32_t *dest, uint32_t *src, uint32_t size)
 {
 	for (int i = 0; i < size; i += 4) {
 		FLASH_CR = FLASH_CR_PROGRAM_X32 | FLASH_CR_PG;

src/target/flashstub/stm32f4_x8.c

@@ -0,0 +1,44 @@
+/*
+ * This file is part of the Black Magic Debug project.
+ *
+ * Copyright (C) 2017  Black Sphere Technologies Ltd.
+ * Written by Gordon Smith <gordonhj.smith@gmail.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "libopencm3/stm32/flash.h"
+#include "stub.h"
+
+#define SR_ERROR_MASK 0xF2
+
+void __attribute__((naked))
+stm32f4_flash_write_x8_stub(uint32_t *dest, uint32_t *src, uint32_t size)
+{
+	uint8_t *b_dest, *b_src;
+	b_dest = (void *)dest;
+	b_src = (void *)src;
+	for (int i = 0; i < size; i += 1) {
+		FLASH_CR = FLASH_CR_PROGRAM_X8 | FLASH_CR_PG;
+		*b_dest++ = *b_src++;
+		__asm("dsb");
+		while (FLASH_SR & FLASH_SR_BSY)
+			;
+	}
+
+	if (FLASH_SR & SR_ERROR_MASK)
+		stub_exit(1);
+
+	stub_exit(0);
+}
+

src/target/flashstub/stm32f4_x8.stub

@@ -0,0 +1 @@
+0x2300, 0x4C0A, 0x4293, 0xD00B, 0x2601, 0x4D09, 0x602E, 0x5CCD, 0x54C5, 0xF3BF, 0x8F4F, 0x6825, 0x03ED, 0xD4FC, 0x3301, 0xE7F0, 0x23F2, 0x6822, 0x421A, 0xD000, 0xBE01, 0xBE00, 0x3C0C, 0x4002, 0x3C10, 0x4002,

src/target/stm32f4.c

@@ -103,12 +103,19 @@ static const char stm32f2_driver_str[] = "STM32F2xx";
 #define DBG_IWDG_STOP	(1 << 12)
 
 /* This routine uses word access.  Only usable on target voltage >2.7V */
-static const uint16_t stm32f4_flash_write_stub[] = {
-#include "flashstub/stm32f4.stub"
+static const uint16_t stm32f4_flash_write_x32_stub[] = {
+#include "flashstub/stm32f4_x32.stub"
+};
+
+/* This routine uses byte access. Usable on target voltage <2.2V */
+static const uint16_t stm32f4_flash_write_x8_stub[] = {
+#include "flashstub/stm32f4_x8.stub"
 };
 
 #define SRAM_BASE 0x20000000
-#define STUB_BUFFER_BASE ALIGN(SRAM_BASE + sizeof(stm32f4_flash_write_stub), 4)
+#define STUB_BUFFER_BASE \
+	ALIGN(SRAM_BASE + MAX(sizeof(stm32f4_flash_write_x8_stub), \
+			      sizeof(stm32f4_flash_write_x32_stub)), 4)
 
 #define AXIM_BASE 0x8000000
 #define ITCM_BASE 0x0200000
@@ -266,8 +273,8 @@ static int stm32f4_flash_write(struct target_flash *f,
 	}
 
 	/* Write buffer to target ram call stub */
-	target_mem_write(f->t, SRAM_BASE, stm32f4_flash_write_stub,
-	                 sizeof(stm32f4_flash_write_stub));
+	target_mem_write(f->t, SRAM_BASE, stm32f4_flash_write_x8_stub,
+	                 sizeof(stm32f4_flash_write_x8_stub));
 	target_mem_write(f->t, STUB_BUFFER_BASE, src, len);
 	return cortexm_run_stub(f->t, SRAM_BASE, dest,
 	                        STUB_BUFFER_BASE, len, 0);