flash/stm32l4x: zero init stm32l4_flash_bank struct on flash bank initialization
[fw/openocd] / src / flash / nor / stm32l4x.c
index 6a1fa074e33da7fadc4214205314a4825825dcc3..89c5ac3fe28aca757a9ca5135c764f4854257ed1 100644 (file)
@@ -1,7 +1,10 @@
 /***************************************************************************
  *   Copyright (C) 2015 by Uwe Bonnes                                      *
  *   bon@elektron.ikp.physik.tu-darmstadt.de                               *
- *
+ *                                                                         *
+ *   Copyright (C) 2019 by Tarek Bochkati for STMicroelectronics           *
+ *   tarek.bouchkati@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 2 of the License, or     *
@@ -24,6 +27,8 @@
 #include <helper/binarybuffer.h>
 #include <target/algorithm.h>
 #include <target/armv7m.h>
+#include "bits.h"
+#include "stm32l4x.h"
 
 /* STM32L4xxx series for reference.
  *
@@ -33,6 +38,9 @@
  * RM0394 (STM32L43x/44x/45x/46x)
  * http://www.st.com/resource/en/reference_manual/dm00151940.pdf
  *
+ * RM0432 (STM32L4R/4Sxx)
+ * http://www.st.com/resource/en/reference_manual/dm00310109.pdf
+ *
  * STM32L476RG Datasheet (for erase timing)
  * http://www.st.com/resource/en/datasheet/stm32l476rg.pdf
  *
  *
  * RM0394 devices have a single bank only.
  *
+ * RM0432 devices have single and dual bank operating modes.
+ *  - for STM32L4R/Sxx the FLASH size is 2Mbyte or 1Mbyte.
+ *  - for STM32L4P/Q5x the FLASH size is 1Mbyte or 512Kbyte.
+ * Bank page (sector) size is 4Kbyte (dual mode) or 8Kbyte (single mode).
+ *
+ * Bank mode is controlled by two different bits in option bytes register.
+ *  - for STM32L4R/Sxx
+ *    In 2M FLASH devices bit 22 (DBANK) controls Dual Bank mode.
+ *    In 1M FLASH devices bit 21 (DB1M) controls Dual Bank mode.
+ *  - for STM32L4P5/Q5x
+ *    In 1M FLASH devices bit 22 (DBANK) controls Dual Bank mode.
+ *    In 512K FLASH devices bit 21 (DB512K) controls Dual Bank mode.
+ *
+ */
+
+/* STM32WBxxx series for reference.
+ *
+ * RM0434 (STM32WB55)
+ * http://www.st.com/resource/en/reference_manual/dm00318631.pdf
+ *
+ * RM0471 (STM32WB50)
+ * http://www.st.com/resource/en/reference_manual/dm00622834.pdf
+ */
+
+/* STM32WLxxx series for reference.
+ *
+ * RM0461 (STM32WLEx)
+ * http://www.st.com/resource/en/reference_manual/dm00530369.pdf
+ */
+
+/* STM32G0xxx series for reference.
+ *
+ * RM0444 (STM32G0x1)
+ * http://www.st.com/resource/en/reference_manual/dm00371828.pdf
+ *
+ * RM0454 (STM32G0x0)
+ * http://www.st.com/resource/en/reference_manual/dm00463896.pdf
+ */
+
+/* STM32G4xxx series for reference.
+ *
+ * RM0440 (STM32G43x/44x/47x/48x/49x/4Ax)
+ * http://www.st.com/resource/en/reference_manual/dm00355726.pdf
+ *
+ * Cat. 2 devices have single bank only, page size is 2kByte.
+ *
+ * Cat. 3 devices have single and dual bank operating modes,
+ * Page size is 2kByte (dual mode) or 4kByte (single mode).
+ *
+ * Bank mode is controlled by bit 22 (DBANK) in option bytes register.
+ * Both banks are treated as a single OpenOCD bank.
+ *
+ * Cat. 4 devices have single bank only, page size is 2kByte.
+ */
+
+/* STM32L5xxx series for reference.
+ *
+ * RM0428 (STM32L552xx/STM32L562xx)
+ * http://www.st.com/resource/en/reference_manual/dm00346336.pdf
  */
 
 /* Erase time can be as high as 25ms, 10x this and assume it's toast... */
 
 #define FLASH_ERASE_TIMEOUT 250
 
-#define STM32_FLASH_BASE    0x40022000
-#define STM32_FLASH_ACR     0x40022000
-#define STM32_FLASH_KEYR    0x40022008
-#define STM32_FLASH_OPTKEYR 0x4002200c
-#define STM32_FLASH_SR      0x40022010
-#define STM32_FLASH_CR      0x40022014
-#define STM32_FLASH_OPTR    0x40022020
-#define STM32_FLASH_WRP1AR  0x4002202c
-#define STM32_FLASH_WRP2AR  0x40022030
-#define STM32_FLASH_WRP1BR  0x4002204c
-#define STM32_FLASH_WRP2BR  0x40022050
-
-/* FLASH_CR register bits */
-
-#define FLASH_PG       (1 << 0)
-#define FLASH_PER      (1 << 1)
-#define FLASH_MER1     (1 << 2)
-#define FLASH_PAGE_SHIFT     3
-#define FLASH_CR_BKER  (1 << 11)
-#define FLASH_MER2     (1 << 15)
-#define FLASH_STRT     (1 << 16)
-#define FLASH_EOPIE    (1 << 24)
-#define FLASH_ERRIE    (1 << 25)
-#define FLASH_OPTLOCK  (1 << 30)
-#define FLASH_LOCK     (1 << 31)
-
-/* FLASH_SR register bits */
-
-#define FLASH_BSY      (1 << 16)
-/* Fast programming not used => related errors not used*/
-#define FLASH_PGSERR   (1 << 7) /* Programming sequence error */
-#define FLASH_SIZERR   (1 << 6) /* Size  error */
-#define FLASH_PGAERR   (1 << 5) /* Programming alignment error */
-#define FLASH_WRPERR   (1 << 4) /* Write protection error */
-#define FLASH_PROGERR  (1 << 3) /* Programming error */
-#define FLASH_OPERR    (1 << 1) /* Operation error */
-#define FLASH_EOP      (1 << 0) /* End of operation */
-
-#define FLASH_ERROR (FLASH_PGSERR | FLASH_PGSERR | FLASH_PGAERR | FLASH_WRPERR | FLASH_OPERR)
-
-/* STM32_FLASH_OBR bit definitions (reading) */
-
-#define OPT_DUALBANK   21      /* dual flash bank only */
-
-/* register unlock keys */
-
-#define KEY1           0x45670123
-#define KEY2           0xCDEF89AB
-
-/* option register unlock key */
-#define OPTKEY1        0x08192A3B
-#define OPTKEY2        0x4C5D6E7F
-
-
-/* other registers */
-#define DBGMCU_IDCODE  0xE0042000
-#define FLASH_SIZE_REG 0x1FFF75E0
-
-struct stm32l4_options {
-       uint8_t RDP;
-       uint16_t bank_b_start;
-       uint8_t user_options;
-       uint8_t wpr1a_start;
-       uint8_t wpr1a_end;
-       uint8_t wpr1b_start;
-       uint8_t wpr1b_end;
-       uint8_t wpr2a_start;
-       uint8_t wpr2a_end;
-       uint8_t wpr2b_start;
-       uint8_t wpr2b_end;
-    /* Fixme: Handle PCROP */
+enum stm32l4_flash_reg_index {
+       STM32_FLASH_ACR_INDEX,
+       STM32_FLASH_KEYR_INDEX,
+       STM32_FLASH_OPTKEYR_INDEX,
+       STM32_FLASH_SR_INDEX,
+       STM32_FLASH_CR_INDEX,
+       STM32_FLASH_OPTR_INDEX,
+       STM32_FLASH_WRP1AR_INDEX,
+       STM32_FLASH_WRP1BR_INDEX,
+       STM32_FLASH_WRP2AR_INDEX,
+       STM32_FLASH_WRP2BR_INDEX,
+       STM32_FLASH_REG_INDEX_NUM,
+};
+
+static const uint32_t stm32l4_flash_regs[STM32_FLASH_REG_INDEX_NUM] = {
+       [STM32_FLASH_ACR_INDEX]      = 0x000,
+       [STM32_FLASH_KEYR_INDEX]     = 0x008,
+       [STM32_FLASH_OPTKEYR_INDEX]  = 0x00C,
+       [STM32_FLASH_SR_INDEX]       = 0x010,
+       [STM32_FLASH_CR_INDEX]       = 0x014,
+       [STM32_FLASH_OPTR_INDEX]     = 0x020,
+       [STM32_FLASH_WRP1AR_INDEX]   = 0x02C,
+       [STM32_FLASH_WRP1BR_INDEX]   = 0x030,
+       [STM32_FLASH_WRP2AR_INDEX]   = 0x04C,
+       [STM32_FLASH_WRP2BR_INDEX]   = 0x050,
+};
+
+static const uint32_t stm32l5_ns_flash_regs[STM32_FLASH_REG_INDEX_NUM] = {
+       [STM32_FLASH_ACR_INDEX]      = 0x000,
+       [STM32_FLASH_KEYR_INDEX]     = 0x008,
+       [STM32_FLASH_OPTKEYR_INDEX]  = 0x010,
+       [STM32_FLASH_SR_INDEX]       = 0x020,
+       [STM32_FLASH_CR_INDEX]       = 0x028,
+       [STM32_FLASH_OPTR_INDEX]     = 0x040,
+       [STM32_FLASH_WRP1AR_INDEX]   = 0x058,
+       [STM32_FLASH_WRP1BR_INDEX]   = 0x05C,
+       [STM32_FLASH_WRP2AR_INDEX]   = 0x068,
+       [STM32_FLASH_WRP2BR_INDEX]   = 0x06C,
+};
+
+struct stm32l4_rev {
+       const uint16_t rev;
+       const char *str;
+};
+
+struct stm32l4_part_info {
+       uint16_t id;
+       const char *device_str;
+       const struct stm32l4_rev *revs;
+       const size_t num_revs;
+       const uint16_t max_flash_size_kb;
+       const bool has_dual_bank;
+       const uint32_t flash_regs_base;
+       const uint32_t *default_flash_regs;
+       const uint32_t fsize_addr;
 };
 
 struct stm32l4_flash_bank {
-       struct stm32l4_options option_bytes;
-       int probed;
+       bool probed;
+       uint32_t idcode;
+       unsigned int bank1_sectors;
+       bool dual_bank_mode;
+       int hole_sectors;
+       uint32_t user_bank_size;
+       uint32_t wrpxxr_mask;
+       const struct stm32l4_part_info *part_info;
+       const uint32_t *flash_regs;
 };
 
-/* flash bank stm32l4x <base> <size> 0 0 <target#>
- */
+/* human readable list of families this drivers supports (sorted alphabetically) */
+static const char *device_families = "STM32G0/G4/L4/L4+/L5/WB/WL";
+
+static const struct stm32l4_rev stm32_415_revs[] = {
+       { 0x1000, "1" }, { 0x1001, "2" }, { 0x1003, "3" }, { 0x1007, "4" }
+};
+
+static const struct stm32l4_rev stm32_435_revs[] = {
+       { 0x1000, "A" }, { 0x1001, "Z" }, { 0x2001, "Y" },
+};
+
+static const struct stm32l4_rev stm32_460_revs[] = {
+       { 0x1000, "A/Z" } /* A and Z, no typo in RM! */, { 0x2000, "B" },
+};
+
+static const struct stm32l4_rev stm32_461_revs[] = {
+       { 0x1000, "A" }, { 0x2000, "B" },
+};
+
+static const struct stm32l4_rev stm32_462_revs[] = {
+       { 0x1000, "A" }, { 0x1001, "Z" }, { 0x2001, "Y" },
+};
+
+static const struct stm32l4_rev stm32_464_revs[] = {
+       { 0x1000, "A" }, { 0x1001, "Z" }, { 0x2001, "Y" },
+};
+
+static const struct stm32l4_rev stm32_466_revs[] = {
+       { 0x1000, "A" }, { 0x1001, "Z" }, { 0x2000, "B" },
+};
+
+static const struct stm32l4_rev stm32_468_revs[] = {
+       { 0x1000, "A" }, { 0x2000, "B" }, { 0x2001, "Z" },
+};
+
+static const struct stm32l4_rev stm32_469_revs[] = {
+       { 0x1000, "A" }, { 0x2000, "B" }, { 0x2001, "Z" },
+};
+
+static const struct stm32l4_rev stm32_470_revs[] = {
+       { 0x1000, "A" }, { 0x1001, "Z" }, { 0x1003, "Y" }, { 0x100F, "W" },
+};
+
+static const struct stm32l4_rev stm32_471_revs[] = {
+       { 0x1001, "Z" },
+};
+
+static const struct stm32l4_rev stm32_472_revs[] = {
+       { 0x1000, "A" }, { 0x2000, "B" },
+};
+
+static const struct stm32l4_rev stm32_479_revs[] = {
+       { 0x1000, "A" },
+};
+
+static const struct stm32l4_rev stm32_495_revs[] = {
+       { 0x2001, "2.1" },
+};
+
+static const struct stm32l4_rev stm32_496_revs[] = {
+       { 0x1000, "A" },
+};
+
+static const struct stm32l4_rev stm32_497_revs[] = {
+       { 0x1000, "1.0" },
+};
+
+static const struct stm32l4_part_info stm32l4_parts[] = {
+       {
+         .id                    = 0x415,
+         .revs                  = stm32_415_revs,
+         .num_revs              = ARRAY_SIZE(stm32_415_revs),
+         .device_str            = "STM32L47/L48xx",
+         .max_flash_size_kb     = 1024,
+         .has_dual_bank         = true,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x435,
+         .revs                  = stm32_435_revs,
+         .num_revs              = ARRAY_SIZE(stm32_435_revs),
+         .device_str            = "STM32L43/L44xx",
+         .max_flash_size_kb     = 256,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x460,
+         .revs                  = stm32_460_revs,
+         .num_revs              = ARRAY_SIZE(stm32_460_revs),
+         .device_str            = "STM32G07/G08xx",
+         .max_flash_size_kb     = 128,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x461,
+         .revs                  = stm32_461_revs,
+         .num_revs              = ARRAY_SIZE(stm32_461_revs),
+         .device_str            = "STM32L49/L4Axx",
+         .max_flash_size_kb     = 1024,
+         .has_dual_bank         = true,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x462,
+         .revs                  = stm32_462_revs,
+         .num_revs              = ARRAY_SIZE(stm32_462_revs),
+         .device_str            = "STM32L45/L46xx",
+         .max_flash_size_kb     = 512,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x464,
+         .revs                  = stm32_464_revs,
+         .num_revs              = ARRAY_SIZE(stm32_464_revs),
+         .device_str            = "STM32L41/L42xx",
+         .max_flash_size_kb     = 128,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x466,
+         .revs                  = stm32_466_revs,
+         .num_revs              = ARRAY_SIZE(stm32_466_revs),
+         .device_str            = "STM32G03/G04xx",
+         .max_flash_size_kb     = 64,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x468,
+         .revs                  = stm32_468_revs,
+         .num_revs              = ARRAY_SIZE(stm32_468_revs),
+         .device_str            = "STM32G43/G44xx",
+         .max_flash_size_kb     = 128,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x469,
+         .revs                  = stm32_469_revs,
+         .num_revs              = ARRAY_SIZE(stm32_469_revs),
+         .device_str            = "STM32G47/G48xx",
+         .max_flash_size_kb     = 512,
+         .has_dual_bank         = true,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x470,
+         .revs                  = stm32_470_revs,
+         .num_revs              = ARRAY_SIZE(stm32_470_revs),
+         .device_str            = "STM32L4R/L4Sxx",
+         .max_flash_size_kb     = 2048,
+         .has_dual_bank         = true,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x471,
+         .revs                  = stm32_471_revs,
+         .num_revs              = ARRAY_SIZE(stm32_471_revs),
+         .device_str            = "STM32L4P5/L4Q5x",
+         .max_flash_size_kb     = 1024,
+         .has_dual_bank         = true,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x472,
+         .revs                  = stm32_472_revs,
+         .num_revs              = ARRAY_SIZE(stm32_472_revs),
+         .device_str            = "STM32L55/L56xx",
+         .max_flash_size_kb     = 512,
+         .has_dual_bank         = true,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l5_ns_flash_regs,
+         .fsize_addr            = 0x0BFA05E0,
+       },
+       {
+         .id                    = 0x479,
+         .revs                  = stm32_479_revs,
+         .num_revs              = ARRAY_SIZE(stm32_479_revs),
+         .device_str            = "STM32G49/G4Axx",
+         .max_flash_size_kb     = 512,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x40022000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x495,
+         .revs                  = stm32_495_revs,
+         .num_revs              = ARRAY_SIZE(stm32_495_revs),
+         .device_str            = "STM32WB5x",
+         .max_flash_size_kb     = 1024,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x58004000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x496,
+         .revs                  = stm32_496_revs,
+         .num_revs              = ARRAY_SIZE(stm32_496_revs),
+         .device_str            = "STM32WB3x",
+         .max_flash_size_kb     = 512,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x58004000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+       {
+         .id                    = 0x497,
+         .revs                  = stm32_497_revs,
+         .num_revs              = ARRAY_SIZE(stm32_497_revs),
+         .device_str            = "STM32WLEx",
+         .max_flash_size_kb     = 256,
+         .has_dual_bank         = false,
+         .flash_regs_base       = 0x58004000,
+         .default_flash_regs    = stm32l4_flash_regs,
+         .fsize_addr            = 0x1FFF75E0,
+       },
+};
+
+/* flash bank stm32l4x <base> <size> 0 0 <target#> */
 FLASH_BANK_COMMAND_HANDLER(stm32l4_flash_bank_command)
 {
        struct stm32l4_flash_bank *stm32l4_info;
@@ -136,37 +439,66 @@ FLASH_BANK_COMMAND_HANDLER(stm32l4_flash_bank_command)
        if (CMD_ARGC < 6)
                return ERROR_COMMAND_SYNTAX_ERROR;
 
-       stm32l4_info = malloc(sizeof(struct stm32l4_flash_bank));
+       stm32l4_info = calloc(1, sizeof(struct stm32l4_flash_bank));
        if (!stm32l4_info)
                return ERROR_FAIL; /* Checkme: What better error to use?*/
        bank->driver_priv = stm32l4_info;
 
-       stm32l4_info->probed = 0;
+       /* The flash write must be aligned to a double word (8-bytes) boundary.
+        * Ask the flash infrastructure to ensure required alignment */
+       bank->write_start_alignment = bank->write_end_alignment = 8;
+
+       stm32l4_info->probed = false;
+       stm32l4_info->user_bank_size = bank->size;
 
        return ERROR_OK;
 }
 
-static inline int stm32l4_get_flash_reg(struct flash_bank *bank, uint32_t reg)
+static inline uint32_t stm32l4_get_flash_reg(struct flash_bank *bank, uint32_t reg_offset)
 {
-       return reg;
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       return stm32l4_info->part_info->flash_regs_base + reg_offset;
 }
 
-static inline int stm32l4_get_flash_status(struct flash_bank *bank, uint32_t *status)
+static inline uint32_t stm32l4_get_flash_reg_by_index(struct flash_bank *bank,
+       enum stm32l4_flash_reg_index reg_index)
 {
-       struct target *target = bank->target;
-       return target_read_u32(
-               target, stm32l4_get_flash_reg(bank, STM32_FLASH_SR), status);
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       return stm32l4_get_flash_reg(bank, stm32l4_info->flash_regs[reg_index]);
+}
+
+static inline int stm32l4_read_flash_reg(struct flash_bank *bank, uint32_t reg_offset, uint32_t *value)
+{
+       return target_read_u32(bank->target, stm32l4_get_flash_reg(bank, reg_offset), value);
+}
+
+static inline int stm32l4_read_flash_reg_by_index(struct flash_bank *bank,
+       enum stm32l4_flash_reg_index reg_index, uint32_t *value)
+{
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       return stm32l4_read_flash_reg(bank, stm32l4_info->flash_regs[reg_index], value);
+}
+
+static inline int stm32l4_write_flash_reg(struct flash_bank *bank, uint32_t reg_offset, uint32_t value)
+{
+       return target_write_u32(bank->target, stm32l4_get_flash_reg(bank, reg_offset), value);
+}
+
+static inline int stm32l4_write_flash_reg_by_index(struct flash_bank *bank,
+       enum stm32l4_flash_reg_index reg_index, uint32_t value)
+{
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       return stm32l4_write_flash_reg(bank, stm32l4_info->flash_regs[reg_index], value);
 }
 
 static int stm32l4_wait_status_busy(struct flash_bank *bank, int timeout)
 {
-       struct target *target = bank->target;
        uint32_t status;
        int retval = ERROR_OK;
 
        /* wait for busy to clear */
        for (;;) {
-               retval = stm32l4_get_flash_status(bank, &status);
+               retval = stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_SR_INDEX, &status);
                if (retval != ERROR_OK)
                        return retval;
                LOG_DEBUG("status: 0x%" PRIx32 "", status);
@@ -179,7 +511,6 @@ static int stm32l4_wait_status_busy(struct flash_bank *bank, int timeout)
                alive_sleep(1);
        }
 
-
        if (status & FLASH_WRPERR) {
                LOG_ERROR("stm32x device protected");
                retval = ERROR_FAIL;
@@ -187,23 +518,25 @@ static int stm32l4_wait_status_busy(struct flash_bank *bank, int timeout)
 
        /* Clear but report errors */
        if (status & FLASH_ERROR) {
+               if (retval == ERROR_OK)
+                       retval = ERROR_FAIL;
                /* If this operation fails, we ignore it and report the original
                 * retval
                 */
-               target_write_u32(target, stm32l4_get_flash_reg(bank, STM32_FLASH_SR),
-                               status & FLASH_ERROR);
+               stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_SR_INDEX, status & FLASH_ERROR);
        }
+
        return retval;
 }
 
-static int stm32l4_unlock_reg(struct target *target)
+static int stm32l4_unlock_reg(struct flash_bank *bank)
 {
        uint32_t ctrl;
 
        /* first check if not already unlocked
         * otherwise writing on STM32_FLASH_KEYR will fail
         */
-       int retval = target_read_u32(target, STM32_FLASH_CR, &ctrl);
+       int retval = stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, &ctrl);
        if (retval != ERROR_OK)
                return retval;
 
@@ -211,15 +544,15 @@ static int stm32l4_unlock_reg(struct target *target)
                return ERROR_OK;
 
        /* unlock flash registers */
-       retval = target_write_u32(target, STM32_FLASH_KEYR, KEY1);
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_KEYR_INDEX, KEY1);
        if (retval != ERROR_OK)
                return retval;
 
-       retval = target_write_u32(target, STM32_FLASH_KEYR, KEY2);
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_KEYR_INDEX, KEY2);
        if (retval != ERROR_OK)
                return retval;
 
-       retval = target_read_u32(target, STM32_FLASH_CR, &ctrl);
+       retval = stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, &ctrl);
        if (retval != ERROR_OK)
                return retval;
 
@@ -231,11 +564,11 @@ static int stm32l4_unlock_reg(struct target *target)
        return ERROR_OK;
 }
 
-static int stm32l4_unlock_option_reg(struct target *target)
+static int stm32l4_unlock_option_reg(struct flash_bank *bank)
 {
        uint32_t ctrl;
 
-       int retval = target_read_u32(target, STM32_FLASH_CR, &ctrl);
+       int retval = stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, &ctrl);
        if (retval != ERROR_OK)
                return retval;
 
@@ -243,15 +576,15 @@ static int stm32l4_unlock_option_reg(struct target *target)
                return ERROR_OK;
 
        /* unlock option registers */
-       retval = target_write_u32(target, STM32_FLASH_OPTKEYR, OPTKEY1);
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_OPTKEYR_INDEX, OPTKEY1);
        if (retval != ERROR_OK)
                return retval;
 
-       retval = target_write_u32(target, STM32_FLASH_OPTKEYR, OPTKEY2);
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_OPTKEYR_INDEX, OPTKEY2);
        if (retval != ERROR_OK)
                return retval;
 
-       retval = target_read_u32(target, STM32_FLASH_CR, &ctrl);
+       retval = stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, &ctrl);
        if (retval != ERROR_OK)
                return retval;
 
@@ -263,97 +596,87 @@ static int stm32l4_unlock_option_reg(struct target *target)
        return ERROR_OK;
 }
 
-static int stm32l4_read_options(struct flash_bank *bank)
+static int stm32l4_write_option(struct flash_bank *bank, uint32_t reg_offset,
+       uint32_t value, uint32_t mask)
 {
        uint32_t optiondata;
-       struct stm32l4_flash_bank *stm32l4_info = NULL;
-       struct target *target = bank->target;
-
-       stm32l4_info = bank->driver_priv;
+       int retval, retval2;
 
-       /* read current option bytes */
-       int retval = target_read_u32(target, STM32_FLASH_OPTR, &optiondata);
+       retval = stm32l4_read_flash_reg(bank, reg_offset, &optiondata);
        if (retval != ERROR_OK)
                return retval;
 
-       stm32l4_info->option_bytes.user_options = (optiondata >> 8) & 0x3ffff;
-       stm32l4_info->option_bytes.RDP = optiondata & 0xff;
-
-       retval = target_read_u32(target, STM32_FLASH_WRP1AR, &optiondata);
+       retval = stm32l4_unlock_reg(bank);
        if (retval != ERROR_OK)
-               return retval;
-       stm32l4_info->option_bytes.wpr1a_start =  optiondata         & 0xff;
-       stm32l4_info->option_bytes.wpr1a_end   = (optiondata >> 16)  & 0xff;
+               goto err_lock;
 
-       retval = target_read_u32(target, STM32_FLASH_WRP2AR, &optiondata);
+       retval = stm32l4_unlock_option_reg(bank);
        if (retval != ERROR_OK)
-               return retval;
-       stm32l4_info->option_bytes.wpr2a_start =  optiondata         & 0xff;
-       stm32l4_info->option_bytes.wpr2a_end   = (optiondata >> 16)  & 0xff;
+               goto err_lock;
 
-       retval = target_read_u32(target, STM32_FLASH_WRP1BR, &optiondata);
-       if (retval != ERROR_OK)
-               return retval;
-       stm32l4_info->option_bytes.wpr1b_start =  optiondata         & 0xff;
-       stm32l4_info->option_bytes.wpr1b_end   = (optiondata >> 16)  & 0xff;
+       optiondata = (optiondata & ~mask) | (value & mask);
 
-       retval = target_read_u32(target, STM32_FLASH_WRP2BR, &optiondata);
+       retval = stm32l4_write_flash_reg(bank, reg_offset, optiondata);
        if (retval != ERROR_OK)
-               return retval;
-       stm32l4_info->option_bytes.wpr2b_start =  optiondata         & 0xff;
-       stm32l4_info->option_bytes.wpr2b_end   = (optiondata >> 16)  & 0xff;
-
-       if (stm32l4_info->option_bytes.RDP != 0xAA)
-               LOG_INFO("Device Security Bit Set");
+               goto err_lock;
 
-       return ERROR_OK;
-}
-
-static int stm32l4_write_options(struct flash_bank *bank)
-{
-       struct stm32l4_flash_bank *stm32l4_info = NULL;
-       struct target *target = bank->target;
-       uint32_t optiondata;
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_OPTSTRT);
+       if (retval != ERROR_OK)
+               goto err_lock;
 
-       stm32l4_info = bank->driver_priv;
+       retval = stm32l4_wait_status_busy(bank, FLASH_ERASE_TIMEOUT);
 
-       (void) optiondata;
-       (void) stm32l4_info;
+err_lock:
+       retval2 = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_LOCK | FLASH_OPTLOCK);
 
-       int retval = stm32l4_unlock_option_reg(target);
        if (retval != ERROR_OK)
                return retval;
-       /* FIXME: Implement Option writing!*/
-       return ERROR_OK;
+
+       return retval2;
 }
 
 static int stm32l4_protect_check(struct flash_bank *bank)
 {
        struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
 
-       /* read write protection settings */
-       int retval = stm32l4_read_options(bank);
-       if (retval != ERROR_OK) {
-               LOG_DEBUG("unable to read option bytes");
-               return retval;
+       uint32_t wrp1ar, wrp1br, wrp2ar, wrp2br;
+       stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_WRP1AR_INDEX, &wrp1ar);
+       stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_WRP1BR_INDEX, &wrp1br);
+       if (stm32l4_info->part_info->has_dual_bank) {
+               stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_WRP2AR_INDEX, &wrp2ar);
+               stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_WRP2BR_INDEX, &wrp2br);
+       } else {
+               /* prevent uninitialized errors */
+               wrp2ar = 0;
+               wrp2br = 0;
        }
 
-       for (int i = 0; i < bank->num_sectors; i++) {
-               if (i < stm32l4_info->option_bytes.bank_b_start) {
-                       if (((i >= stm32l4_info->option_bytes.wpr1a_start) &&
-                                (i <= stm32l4_info->option_bytes.wpr1a_end)) ||
-                               ((i >= stm32l4_info->option_bytes.wpr2a_start) &&
-                                (i <= stm32l4_info->option_bytes.wpr2a_end)))
+       const uint8_t wrp1a_start = wrp1ar & stm32l4_info->wrpxxr_mask;
+       const uint8_t wrp1a_end = (wrp1ar >> 16) & stm32l4_info->wrpxxr_mask;
+       const uint8_t wrp1b_start = wrp1br & stm32l4_info->wrpxxr_mask;
+       const uint8_t wrp1b_end = (wrp1br >> 16) & stm32l4_info->wrpxxr_mask;
+       const uint8_t wrp2a_start = wrp2ar & stm32l4_info->wrpxxr_mask;
+       const uint8_t wrp2a_end = (wrp2ar >> 16) & stm32l4_info->wrpxxr_mask;
+       const uint8_t wrp2b_start = wrp2br & stm32l4_info->wrpxxr_mask;
+       const uint8_t wrp2b_end = (wrp2br >> 16) & stm32l4_info->wrpxxr_mask;
+
+       for (unsigned int i = 0; i < bank->num_sectors; i++) {
+               if (i < stm32l4_info->bank1_sectors) {
+                       if (((i >= wrp1a_start) &&
+                                (i <= wrp1a_end)) ||
+                               ((i >= wrp1b_start) &&
+                                (i <= wrp1b_end)))
                                bank->sectors[i].is_protected = 1;
                        else
                                bank->sectors[i].is_protected = 0;
                } else {
+                       assert(stm32l4_info->part_info->has_dual_bank == true);
                        uint8_t snb;
-                       snb = i - stm32l4_info->option_bytes.bank_b_start + 256;
-                       if (((snb >= stm32l4_info->option_bytes.wpr1b_start) &&
-                                (snb <= stm32l4_info->option_bytes.wpr1b_end)) ||
-                               ((snb >= stm32l4_info->option_bytes.wpr2b_start) &&
-                                (snb <= stm32l4_info->option_bytes.wpr2b_end)))
+                       snb = i - stm32l4_info->bank1_sectors;
+                       if (((snb >= wrp2a_start) &&
+                                (snb <= wrp2a_end)) ||
+                               ((snb >= wrp2b_start) &&
+                                (snb <= wrp2b_end)))
                                bank->sectors[i].is_protected = 1;
                        else
                                bank->sectors[i].is_protected = 0;
@@ -362,67 +685,66 @@ static int stm32l4_protect_check(struct flash_bank *bank)
        return ERROR_OK;
 }
 
-static int stm32l4_erase(struct flash_bank *bank, int first, int last)
+static int stm32l4_erase(struct flash_bank *bank, unsigned int first,
+               unsigned int last)
 {
-       struct target *target = bank->target;
-       int i;
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       int retval, retval2;
 
-       assert(first < bank->num_sectors);
-       assert(last < bank->num_sectors);
+       assert((first <= last) && (last < bank->num_sectors));
 
        if (bank->target->state != TARGET_HALTED) {
                LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       int retval;
-       retval = stm32l4_unlock_reg(target);
+       retval = stm32l4_unlock_reg(bank);
        if (retval != ERROR_OK)
-               return retval;
+               goto err_lock;
 
        /*
        Sector Erase
        To erase a sector, follow the procedure below:
        1. Check that no Flash memory operation is ongoing by
-       checking the BSY bit in the FLASH_SR register
+          checking the BSY bit in the FLASH_SR register
        2. Set the PER bit and select the page and bank
-          you wish to erase  in the FLASH_CR register
+          you wish to erase in the FLASH_CR register
        3. Set the STRT bit in the FLASH_CR register
        4. Wait for the BSY bit to be cleared
         */
-       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
 
-       for (i = first; i <= last; i++) {
+       for (unsigned int i = first; i <= last; i++) {
                uint32_t erase_flags;
                erase_flags = FLASH_PER | FLASH_STRT;
 
-               if  (i >= stm32l4_info->option_bytes.bank_b_start) {
+               if (i >= stm32l4_info->bank1_sectors) {
                        uint8_t snb;
-                       snb = (i - stm32l4_info->option_bytes.bank_b_start) + 256;
+                       snb = i - stm32l4_info->bank1_sectors;
                        erase_flags |= snb << FLASH_PAGE_SHIFT | FLASH_CR_BKER;
                } else
                        erase_flags |= i << FLASH_PAGE_SHIFT;
-               retval = target_write_u32(target,
-                               stm32l4_get_flash_reg(bank, STM32_FLASH_CR), erase_flags);
+               retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, erase_flags);
                if (retval != ERROR_OK)
-                       return retval;
+                       break;
 
                retval = stm32l4_wait_status_busy(bank, FLASH_ERASE_TIMEOUT);
                if (retval != ERROR_OK)
-                       return retval;
+                       break;
 
                bank->sectors[i].is_erased = 1;
        }
 
-       retval = target_write_u32(
-               target, stm32l4_get_flash_reg(bank, STM32_FLASH_CR), FLASH_LOCK);
+err_lock:
+       retval2 = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_LOCK);
+
        if (retval != ERROR_OK)
                return retval;
 
-       return ERROR_OK;
+       return retval2;
 }
 
-static int stm32l4_protect(struct flash_bank *bank, int set, int first, int last)
+static int stm32l4_protect(struct flash_bank *bank, int set, unsigned int first,
+               unsigned int last)
 {
        struct target *target = bank->target;
        struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
@@ -432,48 +754,46 @@ static int stm32l4_protect(struct flash_bank *bank, int set, int first, int last
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       /* read protection settings */
-       int retval = stm32l4_read_options(bank);
-       if (retval != ERROR_OK) {
-               LOG_DEBUG("unable to read option bytes");
-               return retval;
+       int ret = ERROR_OK;
+       /* Bank 2 */
+       uint32_t reg_value = 0xFF; /* Default to bank un-protected */
+       if (last >= stm32l4_info->bank1_sectors) {
+               if (set == 1) {
+                       uint8_t begin = first > stm32l4_info->bank1_sectors ? first : 0x00;
+                       reg_value = ((last & 0xFF) << 16) | begin;
+               }
+
+               ret = stm32l4_write_option(bank, stm32l4_info->flash_regs[STM32_FLASH_WRP2AR_INDEX], reg_value, 0xffffffff);
        }
+       /* Bank 1 */
+       reg_value = 0xFF; /* Default to bank un-protected */
+       if (first < stm32l4_info->bank1_sectors) {
+               if (set == 1) {
+                       uint8_t end = last >= stm32l4_info->bank1_sectors ? 0xFF : last;
+                       reg_value = (end << 16) | (first & 0xFF);
+               }
 
-       (void)stm32l4_info;
-       /* FIXME: Write First and last in a valid WRPxx_start/end combo*/
-       retval = stm32l4_write_options(bank);
-       if (retval != ERROR_OK)
-               return retval;
+               ret = stm32l4_write_option(bank, stm32l4_info->flash_regs[STM32_FLASH_WRP1AR_INDEX], reg_value, 0xffffffff);
+       }
 
-       return ERROR_OK;
+       return ret;
 }
 
-/* Count is in halfwords */
+/* Count is in double-words */
 static int stm32l4_write_block(struct flash_bank *bank, const uint8_t *buffer,
-               uint32_t offset, uint32_t count)
+       uint32_t offset, uint32_t count)
 {
        struct target *target = bank->target;
-       uint32_t buffer_size = 16384;
+       uint32_t buffer_size;
        struct working_area *write_algorithm;
        struct working_area *source;
        uint32_t address = bank->base + offset;
-       struct reg_param reg_params[5];
+       struct reg_param reg_params[6];
        struct armv7m_algorithm armv7m_info;
        int retval = ERROR_OK;
 
-       /* See contrib/loaders/flash/stm32l4x.S for source and
-        * hints how to generate the data!
-        */
-
        static const uint8_t stm32l4_flash_write_code[] = {
-               0xd0, 0xf8, 0x00, 0x80, 0xb8, 0xf1, 0x00, 0x0f, 0x21, 0xd0, 0x45, 0x68,
-               0xb8, 0xeb, 0x05, 0x06, 0x44, 0xbf, 0x76, 0x18, 0x36, 0x1a, 0x08, 0x2e,
-               0xf2, 0xd3, 0xdf, 0xf8, 0x36, 0x60, 0x66, 0x61, 0xf5, 0xe8, 0x02, 0x67,
-               0xe2, 0xe8, 0x02, 0x67, 0xbf, 0xf3, 0x4f, 0x8f, 0x26, 0x69, 0x16, 0xf4,
-               0x80, 0x3f, 0xfb, 0xd1, 0x16, 0xf0, 0xfa, 0x0f, 0x07, 0xd1, 0x8d, 0x42,
-               0x28, 0xbf, 0x00, 0xf1, 0x08, 0x05, 0x45, 0x60, 0x01, 0x3b, 0x13, 0xb1,
-               0xda, 0xe7, 0x00, 0x21, 0x41, 0x60, 0x30, 0x46, 0x00, 0xbe, 0x01, 0x00,
-               0x00, 0x00
+#include "../../../contrib/loaders/flash/stm32/stm32l4x.inc"
        };
 
        if (target_alloc_working_area(target, sizeof(stm32l4_flash_write_code),
@@ -485,21 +805,24 @@ static int stm32l4_write_block(struct flash_bank *bank, const uint8_t *buffer,
        retval = target_write_buffer(target, write_algorithm->address,
                        sizeof(stm32l4_flash_write_code),
                        stm32l4_flash_write_code);
-       if (retval != ERROR_OK)
+       if (retval != ERROR_OK) {
+               target_free_working_area(target, write_algorithm);
                return retval;
+       }
 
-       /* memory buffer */
-       while (target_alloc_working_area_try(target, buffer_size, &source) !=
-                  ERROR_OK) {
-               buffer_size /= 2;
-               if (buffer_size <= 256) {
-                       /* we already allocated the writing code, but failed to get a
-                        * buffer, free the algorithm */
-                       target_free_working_area(target, write_algorithm);
-
-                       LOG_WARNING("no large enough working area available, can't do block memory writes");
-                       return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
-               }
+       /* memory buffer, size *must* be multiple of dword plus one dword for rp and one for wp */
+       buffer_size = target_get_working_area_avail(target) & ~(2 * sizeof(uint32_t) - 1);
+       if (buffer_size < 256) {
+               LOG_WARNING("large enough working area not available, can't do block memory writes");
+               return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
+       } else if (buffer_size > 16384) {
+               /* probably won't benefit from more than 16k ... */
+               buffer_size = 16384;
+       }
+
+       if (target_alloc_working_area_try(target, buffer_size, &source) != ERROR_OK) {
+               LOG_ERROR("allocating working area failed");
+               return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
 
        armv7m_info.common_magic = ARMV7M_COMMON_MAGIC;
@@ -509,17 +832,19 @@ static int stm32l4_write_block(struct flash_bank *bank, const uint8_t *buffer,
        init_reg_param(&reg_params[1], "r1", 32, PARAM_OUT);    /* buffer end */
        init_reg_param(&reg_params[2], "r2", 32, PARAM_OUT);    /* target address */
        init_reg_param(&reg_params[3], "r3", 32, PARAM_OUT);    /* count (double word-64bit) */
-       init_reg_param(&reg_params[4], "r4", 32, PARAM_OUT);    /* flash base */
+       init_reg_param(&reg_params[4], "r4", 32, PARAM_OUT);    /* flash status register */
+       init_reg_param(&reg_params[5], "r5", 32, PARAM_OUT);    /* flash control register */
 
        buf_set_u32(reg_params[0].value, 0, 32, source->address);
        buf_set_u32(reg_params[1].value, 0, 32, source->address + source->size);
        buf_set_u32(reg_params[2].value, 0, 32, address);
-       buf_set_u32(reg_params[3].value, 0, 32, count / 4);
-       buf_set_u32(reg_params[4].value, 0, 32, STM32_FLASH_BASE);
+       buf_set_u32(reg_params[3].value, 0, 32, count);
+       buf_set_u32(reg_params[4].value, 0, 32, stm32l4_get_flash_reg_by_index(bank, STM32_FLASH_SR_INDEX));
+       buf_set_u32(reg_params[5].value, 0, 32, stm32l4_get_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX));
 
-       retval = target_run_flash_async_algorithm(target, buffer, count, 2,
+       retval = target_run_flash_async_algorithm(target, buffer, count, 8,
                        0, NULL,
-                       5, reg_params,
+                       ARRAY_SIZE(reg_params), reg_params,
                        source->address, source->size,
                        write_algorithm->address, 0,
                        &armv7m_info);
@@ -535,7 +860,7 @@ static int stm32l4_write_block(struct flash_bank *bank, const uint8_t *buffer,
                if (error != 0) {
                        LOG_ERROR("flash write failed = %08" PRIx32, error);
                        /* Clear but report errors */
-                       target_write_u32(target, STM32_FLASH_SR, error);
+                       stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_SR_INDEX, error);
                        retval = ERROR_FAIL;
                }
        }
@@ -548,149 +873,328 @@ static int stm32l4_write_block(struct flash_bank *bank, const uint8_t *buffer,
        destroy_reg_param(&reg_params[2]);
        destroy_reg_param(&reg_params[3]);
        destroy_reg_param(&reg_params[4]);
+       destroy_reg_param(&reg_params[5]);
 
        return retval;
 }
 
 static int stm32l4_write(struct flash_bank *bank, const uint8_t *buffer,
-               uint32_t offset, uint32_t count)
+       uint32_t offset, uint32_t count)
 {
-       struct target *target = bank->target;
-       int retval;
+       int retval = ERROR_OK, retval2;
 
        if (bank->target->state != TARGET_HALTED) {
                LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       if (offset & 0x7) {
-               LOG_WARNING("offset 0x%" PRIx32 " breaks required 8-byte alignment",
-                                       offset);
-               return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
+       /* The flash write must be aligned to a double word (8-bytes) boundary.
+        * The flash infrastructure ensures it, do just a security check */
+       assert(offset % 8 == 0);
+       assert(count % 8 == 0);
+
+       /* STM32G4xxx Cat. 3 devices may have gaps between banks, check whether
+        * data to be written does not go into a gap:
+        * suppose buffer is fully contained in bank from sector 0 to sector
+        * num->sectors - 1 and sectors are ordered according to offset
+        */
+       struct flash_sector *head = &bank->sectors[0];
+       struct flash_sector *tail = &bank->sectors[bank->num_sectors - 1];
+
+       while ((head < tail) && (offset >= (head + 1)->offset)) {
+               /* buffer does not intersect head nor gap behind head */
+               head++;
        }
 
-       if (count & 0x7) {
-               LOG_WARNING("Padding %d bytes to keep 8-byte write size",
-                                       count & 7);
-               count = (count + 7) & ~7;
-               /* This pads the write chunk with random bytes by overrunning the
-                * write buffer. Padding with the erased pattern 0xff is purely
-                * cosmetical, as 8-byte flash words are ECC secured and the first
-                * write will program the ECC bits. A second write would need
-                * to reprogramm these ECC bits.
-                * But this can only be done after erase!
-                */
+       while ((head < tail) && (offset + count <= (tail - 1)->offset + (tail - 1)->size)) {
+               /* buffer does not intersect tail nor gap before tail */
+               --tail;
+       }
+
+       LOG_DEBUG("data: 0x%08" PRIx32 " - 0x%08" PRIx32 ", sectors: 0x%08" PRIx32 " - 0x%08" PRIx32,
+               offset, offset + count - 1, head->offset, tail->offset + tail->size - 1);
+
+       /* Now check that there is no gap from head to tail, this should work
+        * even for multiple or non-symmetric gaps
+        */
+       while (head < tail) {
+               if (head->offset + head->size != (head + 1)->offset) {
+                       LOG_ERROR("write into gap from " TARGET_ADDR_FMT " to " TARGET_ADDR_FMT,
+                               bank->base + head->offset + head->size,
+                               bank->base + (head + 1)->offset - 1);
+                       retval = ERROR_FLASH_DST_OUT_OF_BANK;
+               }
+               head++;
        }
 
-       retval = stm32l4_unlock_reg(target);
        if (retval != ERROR_OK)
                return retval;
 
-       /* Only full double words (8-byte) can be programmed*/
-       retval = stm32l4_write_block(bank, buffer, offset, count / 2);
+       retval = stm32l4_unlock_reg(bank);
+       if (retval != ERROR_OK)
+               goto err_lock;
+
+       retval = stm32l4_write_block(bank, buffer, offset, count / 8);
+
+err_lock:
+       retval2 = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_LOCK);
+
        if (retval != ERROR_OK) {
-               LOG_WARNING("block write failed");
+               LOG_ERROR("block write failed");
                return retval;
-               }
+       }
+       return retval2;
+}
+
+static int stm32l4_read_idcode(struct flash_bank *bank, uint32_t *id)
+{
+       int retval;
+
+       /* try reading possible IDCODE registers, in the following order */
+       uint32_t DBGMCU_IDCODE[] = {DBGMCU_IDCODE_L4_G4, DBGMCU_IDCODE_G0, DBGMCU_IDCODE_L5};
+
+       for (unsigned int i = 0; i < ARRAY_SIZE(DBGMCU_IDCODE); i++) {
+               retval = target_read_u32(bank->target, DBGMCU_IDCODE[i], id);
+               if ((retval == ERROR_OK) && ((*id & 0xfff) != 0) && ((*id & 0xfff) != 0xfff))
+                       return ERROR_OK;
+       }
 
-       LOG_WARNING("block write succeeded");
-       return target_write_u32(target, STM32_FLASH_CR, FLASH_LOCK);
+       LOG_ERROR("can't get the device id");
+       return (retval == ERROR_OK) ? ERROR_FAIL : retval;
 }
 
 static int stm32l4_probe(struct flash_bank *bank)
 {
        struct target *target = bank->target;
        struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
-       int i;
-       uint16_t flash_size_in_kb = 0xffff;
-       uint16_t max_flash_size_in_kb;
+       const struct stm32l4_part_info *part_info;
+       uint16_t flash_size_kb = 0xffff;
        uint32_t device_id;
        uint32_t options;
-       uint32_t base_address = 0x08000000;
 
-       stm32l4_info->probed = 0;
+       stm32l4_info->probed = false;
 
-       /* read stm32 device id register */
-       int retval = target_read_u32(target, DBGMCU_IDCODE, &device_id);
+       /* read stm32 device id registers */
+       int retval = stm32l4_read_idcode(bank, &stm32l4_info->idcode);
        if (retval != ERROR_OK)
                return retval;
-       LOG_INFO("device id = 0x%08" PRIx32 "", device_id);
 
-       /* set max flash size depending on family */
-       switch (device_id & 0xfff) {
-       case 0x461:
-       case 0x415:
-               max_flash_size_in_kb = 1024;
-               break;
-       case 0x462:
-               max_flash_size_in_kb = 512;
-               break;
-       case 0x435:
-               max_flash_size_in_kb = 256;
-               break;
-       default:
-               LOG_WARNING("Cannot identify target as a STM32L4 family.");
+       device_id = stm32l4_info->idcode & 0xFFF;
+
+       for (unsigned int n = 0; n < ARRAY_SIZE(stm32l4_parts); n++) {
+               if (device_id == stm32l4_parts[n].id)
+                       stm32l4_info->part_info = &stm32l4_parts[n];
+       }
+
+       if (!stm32l4_info->part_info) {
+               LOG_WARNING("Cannot identify target as an %s family device.", device_families);
                return ERROR_FAIL;
        }
 
+       part_info = stm32l4_info->part_info;
+       stm32l4_info->flash_regs = stm32l4_info->part_info->default_flash_regs;
+
+       char device_info[1024];
+       retval = bank->driver->info(bank, device_info, sizeof(device_info));
+       if (retval != ERROR_OK)
+               return retval;
+
+       LOG_INFO("device idcode = 0x%08" PRIx32 " (%s)", stm32l4_info->idcode, device_info);
+
        /* get flash size from target. */
-       retval = target_read_u16(target, FLASH_SIZE_REG, &flash_size_in_kb);
+       retval = target_read_u16(target, part_info->fsize_addr, &flash_size_kb);
 
        /* failed reading flash size or flash size invalid (early silicon),
         * default to max target family */
-       if (retval != ERROR_OK || flash_size_in_kb == 0xffff || flash_size_in_kb == 0) {
+       if (retval != ERROR_OK || flash_size_kb == 0xffff || flash_size_kb == 0
+                       || flash_size_kb > part_info->max_flash_size_kb) {
                LOG_WARNING("STM32 flash size failed, probe inaccurate - assuming %dk flash",
-                       max_flash_size_in_kb);
-               flash_size_in_kb = max_flash_size_in_kb;
+                       part_info->max_flash_size_kb);
+               flash_size_kb = part_info->max_flash_size_kb;
        }
 
-       LOG_INFO("flash size = %dkbytes", flash_size_in_kb);
+       /* if the user sets the size manually then ignore the probed value
+        * this allows us to work around devices that have a invalid flash size register value */
+       if (stm32l4_info->user_bank_size) {
+               LOG_WARNING("overriding size register by configured bank size - MAY CAUSE TROUBLE");
+               flash_size_kb = stm32l4_info->user_bank_size / 1024;
+       }
 
-       /* did we assign flash size? */
-       assert(flash_size_in_kb != 0xffff);
+       LOG_INFO("flash size = %dkbytes", flash_size_kb);
 
-       /* get options to for DUAL BANK. */
-       retval = target_read_u32(target, STM32_FLASH_OPTR, &options);
+       /* did we assign a flash size? */
+       assert((flash_size_kb != 0xffff) && flash_size_kb);
 
+       /* read flash option register */
+       retval = stm32l4_read_flash_reg_by_index(bank, STM32_FLASH_OPTR_INDEX, &options);
        if (retval != ERROR_OK)
                return retval;
 
-       /* only devices with < 1024 kiB may be set to single bank dual banks */
-       if ((flash_size_in_kb == 1024) || !(options & OPT_DUALBANK))
-               stm32l4_info->option_bytes.bank_b_start = 256;
-       else
-               stm32l4_info->option_bytes.bank_b_start = flash_size_in_kb << 9;
+       stm32l4_info->bank1_sectors = 0;
+       stm32l4_info->hole_sectors = 0;
+
+       int num_pages = 0;
+       int page_size_kb = 0;
+
+       stm32l4_info->dual_bank_mode = false;
+       bool use_dbank_bit = false;
 
-       /* did we assign flash size? */
-       assert((flash_size_in_kb != 0xffff) && flash_size_in_kb);
+       switch (device_id) {
+       case 0x415: /* STM32L47/L48xx */
+       case 0x461: /* STM32L49/L4Axx */
+               /* if flash size is max (1M) the device is always dual bank
+                * 0x415: has variants with 512K
+                * 0x461: has variants with 512 and 256
+                * for these variants:
+                *   if DUAL_BANK = 0 -> single bank
+                *   else -> dual bank without gap
+                * note: the page size is invariant
+                */
+               page_size_kb = 2;
+               num_pages = flash_size_kb / page_size_kb;
+               stm32l4_info->bank1_sectors = num_pages;
+
+               /* check DUAL_BANK bit[21] if the flash is less than 1M */
+               if (flash_size_kb == 1024 || (options & BIT(21))) {
+                       stm32l4_info->dual_bank_mode = true;
+                       stm32l4_info->bank1_sectors = num_pages / 2;
+               }
+               break;
+       case 0x435: /* STM32L43/L44xx */
+       case 0x460: /* STM32G07/G08xx */
+       case 0x462: /* STM32L45/L46xx */
+       case 0x464: /* STM32L41/L42xx */
+       case 0x466: /* STM32G03/G04xx */
+       case 0x468: /* STM32G43/G44xx */
+       case 0x479: /* STM32G49/G4Axx */
+       case 0x497: /* STM32WLEx */
+               /* single bank flash */
+               page_size_kb = 2;
+               num_pages = flash_size_kb / page_size_kb;
+               stm32l4_info->bank1_sectors = num_pages;
+               break;
+       case 0x469: /* STM32G47/G48xx */
+               /* STM32G47/8 can be single/dual bank:
+                *   if DUAL_BANK = 0 -> single bank
+                *   else -> dual bank WITH gap
+                */
+               page_size_kb = 4;
+               num_pages = flash_size_kb / page_size_kb;
+               stm32l4_info->bank1_sectors = num_pages;
+               if (options & BIT(22)) {
+                       stm32l4_info->dual_bank_mode = true;
+                       page_size_kb = 2;
+                       num_pages = flash_size_kb / page_size_kb;
+                       stm32l4_info->bank1_sectors = num_pages / 2;
+
+                       /* for devices with trimmed flash, there is a gap between both banks */
+                       stm32l4_info->hole_sectors =
+                               (part_info->max_flash_size_kb - flash_size_kb) / (2 * page_size_kb);
+               }
+               break;
+       case 0x470: /* STM32L4R/L4Sxx */
+       case 0x471: /* STM32L4P5/L4Q5x */
+               /* STM32L4R/S can be single/dual bank:
+                *   if size = 2M check DBANK bit(22)
+                *   if size = 1M check DB1M bit(21)
+                * STM32L4P/Q can be single/dual bank
+                *   if size = 1M check DBANK bit(22)
+                *   if size = 512K check DB512K bit(21)
+                */
+               page_size_kb = 8;
+               num_pages = flash_size_kb / page_size_kb;
+               stm32l4_info->bank1_sectors = num_pages;
+               use_dbank_bit = flash_size_kb == part_info->max_flash_size_kb;
+               if ((use_dbank_bit && (options & BIT(22))) ||
+                       (!use_dbank_bit && (options & BIT(21)))) {
+                       stm32l4_info->dual_bank_mode = true;
+                       page_size_kb = 4;
+                       num_pages = flash_size_kb / page_size_kb;
+                       stm32l4_info->bank1_sectors = num_pages / 2;
+               }
+               break;
+       case 0x472: /* STM32L55/L56xx */
+               /* STM32L55/L56xx can be single/dual bank:
+                *   if size = 512K check DBANK bit(22)
+                *   if size = 256K check DB256K bit(21)
+                */
+               page_size_kb = 4;
+               num_pages = flash_size_kb / page_size_kb;
+               stm32l4_info->bank1_sectors = num_pages;
+               use_dbank_bit = flash_size_kb == part_info->max_flash_size_kb;
+               if ((use_dbank_bit && (options & BIT(22))) ||
+                       (!use_dbank_bit && (options & BIT(21)))) {
+                       stm32l4_info->dual_bank_mode = true;
+                       page_size_kb = 2;
+                       num_pages = flash_size_kb / page_size_kb;
+                       stm32l4_info->bank1_sectors = num_pages / 2;
+               }
+               break;
+       case 0x495: /* STM32WB5x */
+       case 0x496: /* STM32WB3x */
+               /* single bank flash */
+               page_size_kb = 4;
+               num_pages = flash_size_kb / page_size_kb;
+               stm32l4_info->bank1_sectors = num_pages;
+               break;
+       default:
+               LOG_ERROR("unsupported device");
+               return ERROR_FAIL;
+       }
 
-       /* calculate numbers of pages */
-       int num_pages = flash_size_in_kb / 2;
+       LOG_INFO("flash mode : %s-bank", stm32l4_info->dual_bank_mode ? "dual" : "single");
 
-       /* check that calculation result makes sense */
-       assert(num_pages > 0);
+       const int gap_size_kb = stm32l4_info->hole_sectors * page_size_kb;
 
-       if (bank->sectors) {
-               free(bank->sectors);
-               bank->sectors = NULL;
+       if (gap_size_kb != 0) {
+               LOG_INFO("gap detected from 0x%08x to 0x%08x",
+                       STM32_FLASH_BANK_BASE + stm32l4_info->bank1_sectors
+                               * page_size_kb * 1024,
+                       STM32_FLASH_BANK_BASE + (stm32l4_info->bank1_sectors
+                               * page_size_kb + gap_size_kb) * 1024 - 1);
        }
 
-       bank->base = base_address;
-       bank->size = num_pages * (1 << 11);
+       /* number of significant bits in WRPxxR differs per device,
+        * always right adjusted, on some devices non-implemented
+        * bits read as '0', on others as '1' ...
+        * notably G4 Cat. 2 implement only 6 bits, contradicting the RM
+        */
+
+       /* use *max_flash_size* instead of actual size as the trimmed versions
+        * certainly use the same number of bits
+        * max_flash_size is always power of two, so max_pages too
+        */
+       uint32_t max_pages = stm32l4_info->part_info->max_flash_size_kb / page_size_kb;
+       assert((max_pages & (max_pages - 1)) == 0);
+
+       /* in dual bank mode number of pages is doubled, but extra bit is bank selection */
+       stm32l4_info->wrpxxr_mask = ((max_pages >> (stm32l4_info->dual_bank_mode ? 1 : 0)) - 1);
+       assert((stm32l4_info->wrpxxr_mask & 0xFFFF0000) == 0);
+       LOG_DEBUG("WRPxxR mask 0x%04" PRIx16, (uint16_t)stm32l4_info->wrpxxr_mask);
+
+       free(bank->sectors);
+
+       bank->size = (flash_size_kb + gap_size_kb) * 1024;
+       bank->base = STM32_FLASH_BANK_BASE;
        bank->num_sectors = num_pages;
-       bank->sectors = malloc(sizeof(struct flash_sector) * num_pages);
-       if (!bank->sectors)
-               return ERROR_FAIL; /* Checkme: What better error to use?*/
+       bank->sectors = malloc(sizeof(struct flash_sector) * bank->num_sectors);
+       if (bank->sectors == NULL) {
+               LOG_ERROR("failed to allocate bank sectors");
+               return ERROR_FAIL;
+       }
 
-       for (i = 0; i < num_pages; i++) {
-               bank->sectors[i].offset = i << 11;
-               bank->sectors[i].size = 1 << 11;
+       for (unsigned int i = 0; i < bank->num_sectors; i++) {
+               bank->sectors[i].offset = i * page_size_kb * 1024;
+               /* in dual bank configuration, if there is a gap between banks
+                * we fix up the sector offset to consider this gap */
+               if (i >= stm32l4_info->bank1_sectors && stm32l4_info->hole_sectors)
+                       bank->sectors[i].offset += gap_size_kb * 1024;
+               bank->sectors[i].size = page_size_kb * 1024;
                bank->sectors[i].is_erased = -1;
                bank->sectors[i].is_protected = 1;
        }
 
-       stm32l4_info->probed = 1;
-
+       stm32l4_info->probed = true;
        return ERROR_OK;
 }
 
@@ -699,209 +1203,257 @@ static int stm32l4_auto_probe(struct flash_bank *bank)
        struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
        if (stm32l4_info->probed)
                return ERROR_OK;
+
        return stm32l4_probe(bank);
 }
 
 static int get_stm32l4_info(struct flash_bank *bank, char *buf, int buf_size)
 {
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       const struct stm32l4_part_info *part_info = stm32l4_info->part_info;
+
+       if (part_info) {
+               const char *rev_str = NULL;
+               uint16_t rev_id = stm32l4_info->idcode >> 16;
+               for (unsigned int i = 0; i < part_info->num_revs; i++) {
+                       if (rev_id == part_info->revs[i].rev) {
+                               rev_str = part_info->revs[i].str;
+                               break;
+                       }
+               }
+
+               int buf_len = snprintf(buf, buf_size, "%s - Rev %s : 0x%04x",
+                               part_info->device_str, rev_str ? rev_str : "'unknown'", rev_id);
+
+               if (stm32l4_info->probed)
+                       snprintf(buf + buf_len, buf_size - buf_len, " - %s-bank",
+                                       stm32l4_info->dual_bank_mode ? "Flash dual" : "Flash single");
+
+               return ERROR_OK;
+       } else {
+               snprintf(buf, buf_size, "Cannot identify target as an %s device", device_families);
+               return ERROR_FAIL;
+       }
+
+       return ERROR_OK;
+}
+
+static int stm32l4_mass_erase(struct flash_bank *bank)
+{
+       int retval, retval2;
        struct target *target = bank->target;
-       uint32_t dbgmcu_idcode;
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
 
-       /* read stm32 device id register */
-       int retval = target_read_u32(target, DBGMCU_IDCODE, &dbgmcu_idcode);
-       if (retval != ERROR_OK)
-               return retval;
+       uint32_t action = FLASH_MER1;
 
-       uint16_t device_id = dbgmcu_idcode & 0xfff;
-       uint8_t rev_id = dbgmcu_idcode >> 28;
-       uint8_t rev_minor = 0;
-       int i;
+       if (stm32l4_info->part_info->has_dual_bank)
+               action |= FLASH_MER2;
 
-       for (i = 16; i < 28; i++) {
-               if (dbgmcu_idcode & (1 << i))
-                       rev_minor++;
-               else
-                       break;
+       if (target->state != TARGET_HALTED) {
+               LOG_ERROR("Target not halted");
+               return ERROR_TARGET_NOT_HALTED;
        }
 
-       const char *device_str;
+       retval = stm32l4_unlock_reg(bank);
+       if (retval != ERROR_OK)
+               goto err_lock;
 
-       switch (device_id) {
-       case 0x461:
-               device_str = "STM32L496/4A6";
-               break;
+       /* mass erase flash memory */
+       retval = stm32l4_wait_status_busy(bank, FLASH_ERASE_TIMEOUT / 10);
+       if (retval != ERROR_OK)
+               goto err_lock;
 
-       case 0x415:
-               device_str = "STM32L475/476/486";
-               break;
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, action);
+       if (retval != ERROR_OK)
+               goto err_lock;
 
-       case 0x462:
-               device_str = "STM32L45x/46x";
-               break;
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, action | FLASH_STRT);
+       if (retval != ERROR_OK)
+               goto err_lock;
 
-       case 0x435:
-               device_str = "STM32L43x/44x";
-               break;
+       retval = stm32l4_wait_status_busy(bank, FLASH_ERASE_TIMEOUT);
 
-       default:
-               snprintf(buf, buf_size, "Cannot identify target as a STM32L4\n");
-               return ERROR_FAIL;
-       }
+err_lock:
+       retval2 = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_LOCK);
 
-       snprintf(buf, buf_size, "%s - Rev: %1d.%02d",
-                        device_str, rev_id, rev_minor);
+       if (retval != ERROR_OK)
+               return retval;
 
-       return ERROR_OK;
+       return retval2;
 }
 
-COMMAND_HANDLER(stm32l4_handle_lock_command)
+COMMAND_HANDLER(stm32l4_handle_mass_erase_command)
 {
-       struct target *target = NULL;
-       struct stm32l4_flash_bank *stm32l4_info = NULL;
-
-       if (CMD_ARGC < 1)
+       if (CMD_ARGC < 1) {
+               command_print(CMD, "stm32l4x mass_erase <STM32L4 bank>");
                return ERROR_COMMAND_SYNTAX_ERROR;
+       }
 
        struct flash_bank *bank;
        int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
        if (ERROR_OK != retval)
                return retval;
 
-       stm32l4_info = bank->driver_priv;
-       target = bank->target;
+       retval = stm32l4_mass_erase(bank);
+       if (retval == ERROR_OK) {
+               /* set all sectors as erased */
+               for (unsigned int i = 0; i < bank->num_sectors; i++)
+                       bank->sectors[i].is_erased = 1;
 
-       if (target->state != TARGET_HALTED) {
-               LOG_ERROR("Target not halted");
-               return ERROR_TARGET_NOT_HALTED;
+               command_print(CMD, "stm32l4x mass erase complete");
+       } else {
+               command_print(CMD, "stm32l4x mass erase failed");
        }
 
-       if (stm32l4_read_options(bank) != ERROR_OK) {
-               command_print(CMD_CTX, "%s failed to read options",
-                                         bank->driver->name);
-               return ERROR_OK;
+       return retval;
+}
+
+COMMAND_HANDLER(stm32l4_handle_option_read_command)
+{
+       if (CMD_ARGC < 2) {
+               command_print(CMD, "stm32l4x option_read <STM32L4 bank> <option_reg offset>");
+               return ERROR_COMMAND_SYNTAX_ERROR;
        }
 
-       /* set readout protection */
-       stm32l4_info->option_bytes.RDP = 0;
+       struct flash_bank *bank;
+       int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
+       if (ERROR_OK != retval)
+               return retval;
 
-       if (stm32l4_write_options(bank) != ERROR_OK) {
-               command_print(CMD_CTX, "%s failed to lock device", bank->driver->name);
-               return ERROR_OK;
-       }
+       uint32_t reg_offset, reg_addr;
+       uint32_t value = 0;
 
-       command_print(CMD_CTX, "%s locked", bank->driver->name);
+       reg_offset = strtoul(CMD_ARGV[1], NULL, 16);
+       reg_addr = stm32l4_get_flash_reg(bank, reg_offset);
 
-       return ERROR_OK;
+       retval = stm32l4_read_flash_reg(bank, reg_offset, &value);
+       if (ERROR_OK != retval)
+               return retval;
+
+       command_print(CMD, "Option Register: <0x%" PRIx32 "> = 0x%" PRIx32 "", reg_addr, value);
+
+       return retval;
 }
 
-COMMAND_HANDLER(stm32l4_handle_unlock_command)
+COMMAND_HANDLER(stm32l4_handle_option_write_command)
 {
-       struct target *target = NULL;
-       struct stm32l4_flash_bank *stm32l4_info = NULL;
-
-       if (CMD_ARGC < 1)
+       if (CMD_ARGC < 3) {
+               command_print(CMD, "stm32l4x option_write <STM32L4 bank> <option_reg offset> <value> [mask]");
                return ERROR_COMMAND_SYNTAX_ERROR;
+       }
 
        struct flash_bank *bank;
        int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
        if (ERROR_OK != retval)
                return retval;
 
-       stm32l4_info = bank->driver_priv;
-       target = bank->target;
+       uint32_t reg_offset;
+       uint32_t value = 0;
+       uint32_t mask = 0xFFFFFFFF;
 
-       if (target->state != TARGET_HALTED) {
-               LOG_ERROR("Target not halted");
-               return ERROR_TARGET_NOT_HALTED;
-       }
+       reg_offset = strtoul(CMD_ARGV[1], NULL, 16);
+       value = strtoul(CMD_ARGV[2], NULL, 16);
+       if (CMD_ARGC > 3)
+               mask = strtoul(CMD_ARGV[3], NULL, 16);
 
-       if (stm32l4_read_options(bank) != ERROR_OK) {
-               command_print(CMD_CTX, "%s failed to read options", bank->driver->name);
-               return ERROR_OK;
-       }
+       command_print(CMD, "%s Option written.\n"
+                               "INFO: a reset or power cycle is required "
+                               "for the new settings to take effect.", bank->driver->name);
 
-       /* clear readout protection and complementary option bytes
-        * this will also force a device unlock if set */
-       stm32l4_info->option_bytes.RDP = 0xAA;
+       retval = stm32l4_write_option(bank, reg_offset, value, mask);
+       return retval;
+}
 
-       if (stm32l4_write_options(bank) != ERROR_OK) {
-               command_print(CMD_CTX, "%s failed to unlock device",
-                                         bank->driver->name);
-               return ERROR_OK;
-       }
+COMMAND_HANDLER(stm32l4_handle_option_load_command)
+{
+       if (CMD_ARGC != 1)
+               return ERROR_COMMAND_SYNTAX_ERROR;
+
+       struct flash_bank *bank;
+       int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
+       if (ERROR_OK != retval)
+               return retval;
 
-       command_print(CMD_CTX, "%s unlocked.\n"
-                       "INFO: a reset or power cycle is required "
-                       "for the new settings to take effect.", bank->driver->name);
+       retval = stm32l4_unlock_reg(bank);
+       if (ERROR_OK != retval)
+               return retval;
 
-       return ERROR_OK;
+       retval = stm32l4_unlock_option_reg(bank);
+       if (ERROR_OK != retval)
+               return retval;
+
+       /* Set OBL_LAUNCH bit in CR -> system reset and option bytes reload,
+        * but the RMs explicitly do *NOT* list this as power-on reset cause, and:
+        * "Note: If the read protection is set while the debugger is still
+        * connected through JTAG/SWD, apply a POR (power-on reset) instead of a system reset."
+        */
+       retval = stm32l4_write_flash_reg_by_index(bank, STM32_FLASH_CR_INDEX, FLASH_OBL_LAUNCH);
+
+       command_print(CMD, "stm32l4x option load completed. Power-on reset might be required");
+
+       /* Need to re-probe after change */
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       stm32l4_info->probed = false;
+
+       return retval;
 }
 
-static int stm32l4_mass_erase(struct flash_bank *bank, uint32_t action)
+COMMAND_HANDLER(stm32l4_handle_lock_command)
 {
-       int retval;
-       struct target *target = bank->target;
+       struct target *target = NULL;
 
-       if (target->state != TARGET_HALTED) {
-               LOG_ERROR("Target not halted");
-               return ERROR_TARGET_NOT_HALTED;
-       }
+       if (CMD_ARGC < 1)
+               return ERROR_COMMAND_SYNTAX_ERROR;
 
-       retval = stm32l4_unlock_reg(target);
-       if (retval != ERROR_OK)
+       struct flash_bank *bank;
+       int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
+       if (ERROR_OK != retval)
                return retval;
 
-       /* mass erase flash memory */
-       retval = target_write_u32(
-               target, stm32l4_get_flash_reg(bank, STM32_FLASH_CR), action);
-       if (retval != ERROR_OK)
-               return retval;
-       retval = target_write_u32(
-               target, stm32l4_get_flash_reg(bank, STM32_FLASH_CR),
-               action | FLASH_STRT);
-       if (retval != ERROR_OK)
-               return retval;
+       target = bank->target;
 
-       retval = stm32l4_wait_status_busy(bank,  FLASH_ERASE_TIMEOUT);
-       if (retval != ERROR_OK)
-               return retval;
+       if (target->state != TARGET_HALTED) {
+               LOG_ERROR("Target not halted");
+               return ERROR_TARGET_NOT_HALTED;
+       }
 
-       retval = target_write_u32(
-               target, stm32l4_get_flash_reg(bank, STM32_FLASH_CR), FLASH_LOCK);
-       if (retval != ERROR_OK)
-               return retval;
+       /* set readout protection level 1 by erasing the RDP option byte */
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       if (stm32l4_write_option(bank, stm32l4_info->flash_regs[STM32_FLASH_OPTR_INDEX], 0, 0x000000FF) != ERROR_OK) {
+               command_print(CMD, "%s failed to lock device", bank->driver->name);
+               return ERROR_OK;
+       }
 
        return ERROR_OK;
 }
 
-COMMAND_HANDLER(stm32l4_handle_mass_erase_command)
+COMMAND_HANDLER(stm32l4_handle_unlock_command)
 {
-       int i;
-       uint32_t action;
+       struct target *target = NULL;
 
-       if (CMD_ARGC < 1) {
-               command_print(CMD_CTX, "stm32x mass_erase <STM32L4 bank>");
+       if (CMD_ARGC < 1)
                return ERROR_COMMAND_SYNTAX_ERROR;
-       }
 
        struct flash_bank *bank;
        int retval = CALL_COMMAND_HANDLER(flash_command_get_bank, 0, &bank);
        if (ERROR_OK != retval)
                return retval;
 
-       action =  FLASH_MER1 |  FLASH_MER2;
-       retval = stm32l4_mass_erase(bank, action);
-       if (retval == ERROR_OK) {
-               /* set all sectors as erased */
-               for (i = 0; i < bank->num_sectors; i++)
-                       bank->sectors[i].is_erased = 1;
+       target = bank->target;
 
-               command_print(CMD_CTX, "stm32x mass erase complete");
-       } else {
-               command_print(CMD_CTX, "stm32x mass erase failed");
+       if (target->state != TARGET_HALTED) {
+               LOG_ERROR("Target not halted");
+               return ERROR_TARGET_NOT_HALTED;
        }
 
-       return retval;
+       struct stm32l4_flash_bank *stm32l4_info = bank->driver_priv;
+       if (stm32l4_write_option(bank, stm32l4_info->flash_regs[STM32_FLASH_OPTR_INDEX],
+                       RDP_LEVEL_0, 0x000000FF) != ERROR_OK) {
+               command_print(CMD, "%s failed to unlock device", bank->driver->name);
+               return ERROR_OK;
+       }
+
+       return ERROR_OK;
 }
 
 static const struct command_registration stm32l4_exec_command_handlers[] = {
@@ -926,6 +1478,27 @@ static const struct command_registration stm32l4_exec_command_handlers[] = {
                .usage = "bank_id",
                .help = "Erase entire flash device.",
        },
+       {
+               .name = "option_read",
+               .handler = stm32l4_handle_option_read_command,
+               .mode = COMMAND_EXEC,
+               .usage = "bank_id reg_offset",
+               .help = "Read & Display device option bytes.",
+       },
+       {
+               .name = "option_write",
+               .handler = stm32l4_handle_option_write_command,
+               .mode = COMMAND_EXEC,
+               .usage = "bank_id reg_offset value mask",
+               .help = "Write device option bit fields with provided value.",
+       },
+       {
+               .name = "option_load",
+               .handler = stm32l4_handle_option_load_command,
+               .mode = COMMAND_EXEC,
+               .usage = "bank_id",
+               .help = "Force re-load of device options (will cause device reset).",
+       },
        COMMAND_REGISTRATION_DONE
 };
 
@@ -940,7 +1513,7 @@ static const struct command_registration stm32l4_command_handlers[] = {
        COMMAND_REGISTRATION_DONE
 };
 
-struct flash_driver stm32l4x_flash = {
+const struct flash_driver stm32l4x_flash = {
        .name = "stm32l4x",
        .commands = stm32l4_command_handlers,
        .flash_bank_command = stm32l4_flash_bank_command,
@@ -953,4 +1526,5 @@ struct flash_driver stm32l4x_flash = {
        .erase_check = default_flash_blank_check,
        .protect_check = stm32l4_protect_check,
        .info = get_stm32l4_info,
+       .free_driver_priv = default_flash_free_driver_priv,
 };