Add read Option-bytes command for STM32F2 series

include/stlink.h

@@ -222,6 +222,7 @@ typedef struct flash_loader {
     int write_loader_to_sram(stlink_t *sl, stm32_addr_t* addr, size_t* size);
     int stlink_fread(stlink_t* sl, const char* path, bool is_ihex, stm32_addr_t addr, size_t size);
     int stlink_load_device_params(stlink_t *sl);
+    int stlink_read_option_bytes_f2(stlink_t *sl, uint32_t* option_byte);
 
 #include "stlink/sg.h"
 #include "stlink/usb.h"

src/common.c

@@ -2709,6 +2709,39 @@ static int stlink_write_option_bytes_f2(stlink_t *sl, uint32_t option_byte) {
 	return 0;
 }
 
+/**
+ * Read option bytes
+ * @param sl
+ * @param option_byte value to write
+ * @return 0 on success, -ve on failure.
+ */
+int stlink_read_option_bytes_f2(stlink_t *sl, uint32_t* option_byte) {
+    uint32_t val;
+
+    stlink_read_debug32(sl, FLASH_F2_OPT_CR, &val);
+    if (val & FLASH_F2_OPT_LOCK_BIT) {
+        WLOG("Unlocking option flash\n");
+        //Unlock the FLASH_OPT_CR register (FLASH Programming manual page 15)
+        //https://www.st.com/resource/en/programming_manual/cd00233952.pdf
+        stlink_write_debug32(sl, FLASH_F2_OPT_KEYR, 0x08192A3B);
+        stlink_write_debug32(sl, FLASH_F2_OPT_KEYR, 0x4C5D6E7F);
+
+        stlink_read_debug32(sl, FLASH_F2_OPT_CR, &val);
+        if (val & FLASH_F2_OPT_LOCK_BIT) {
+            ELOG("Option flash unlock failed! System reset required to be able to unlock it again!\n");
+            return -1;
+        }
+    }
+
+    stlink_read_debug32(sl, FLASH_F2_OPT_CR, option_byte);
+    WLOG("option bytes CR = %x\n",option_byte);
+
+    WLOG("Option flash re-lock\n");
+    stlink_write_debug32(sl, FLASH_F2_OPT_CR, val | 0x00000001);
+
+	return 0;
+}
+
 /**
  * Write option bytes
  * @param sl

src/tools/flash.c

@@ -39,6 +39,7 @@ static void usage(void)
     puts("                       Format may be 'binary' (default) or 'ihex', although <addr> must be specified for binary format only.");
     puts("                       ./st-flash [--version]");
     puts("example write option byte: ./st-flash --debug --reset --area=option write 0xXXXXXXXX");
+    puts("example read option byte: ./st-flash --debug --reset --area=option read > option_byte");
 }
 
 int main(int ac, char** av)
@@ -208,13 +209,25 @@ int main(int ac, char** av)
     }
     else /* read */
     {
-        if ((o.addr >= sl->flash_base) && (o.size == 0) &&
-                (o.addr < sl->flash_base + sl->flash_size))
+        if(o.area == FLASH_OPTION_BYTES){
+            if(sl->chip_id == STLINK_CHIPID_STM32_F2){
+                uint32_t option_byte = 0;
+                err = stlink_read_option_bytes_f2(sl,&option_byte);
+                printf("%x\n",option_byte);
+            }else{
+                printf("This format is available for STM32F2 Only\n");
+            }
+        }
+        else if ((o.addr >= sl->flash_base) && (o.size == 0) &&
+                (o.addr < sl->flash_base + sl->flash_size)){
             o.size = sl->flash_size;
+            err = stlink_fread(sl, o.filename, o.format == FLASH_FORMAT_IHEX, o.addr, o.size);
+        }
         else if ((o.addr >= sl->sram_base) && (o.size == 0) &&
-                (o.addr < sl->sram_base + sl->sram_size))
+                (o.addr < sl->sram_base + sl->sram_size)){
             o.size = sl->sram_size;
-        err = stlink_fread(sl, o.filename, o.format == FLASH_FORMAT_IHEX, o.addr, o.size);
+            err = stlink_fread(sl, o.filename, o.format == FLASH_FORMAT_IHEX, o.addr, o.size);
+        }
         if (err == -1)
         {
             printf("stlink_fread() == -1\n");

src/tools/flash_opts.c

@@ -172,6 +172,7 @@ int flash_get_opts(struct flash_opts* o, int ac, char** av)
             break;
 
         case FLASH_CMD_READ:     // expect filename, addr and size
+            if((o->area == FLASH_OPTION_BYTES) &&(ac == 0)) break;
             if (ac != 3) return -1;
 
             o->filename = av[0];