]> git.sur5r.net Git - openocd/blobdiff - src/flash/nor/stm32lx.c
stm32: add support for the STM32Lx 384kb dual bank flash
[openocd] / src / flash / nor / stm32lx.c
index 58a2a80b02edb8a1010ee21342b7a41e94ded778..d90b5f6262d3dafc6ea1bb4c42b90e430397a585 100644 (file)
@@ -32,6 +32,7 @@
 #include <helper/binarybuffer.h>
 #include <target/algorithm.h>
 #include <target/armv7m.h>
+#include <target/cortex_m.h>
 
 /* stm32lx flash register locations */
 
@@ -119,8 +120,8 @@ static int stm32lx_erase_sector(struct flash_bank *bank, int sector);
 static int stm32lx_wait_until_bsy_clear(struct flash_bank *bank);
 
 struct stm32lx_flash_bank {
-       struct working_area *write_algorithm;
        int probed;
+       bool has_dual_banks;
 };
 
 /* flash bank stm32lx <base> <size> 0 0 <target#>
@@ -142,8 +143,8 @@ FLASH_BANK_COMMAND_HANDLER(stm32lx_flash_bank_command)
 
        bank->driver_priv = stm32lx_info;
 
-       stm32lx_info->write_algorithm = NULL;
        stm32lx_info->probed = 0;
+       stm32lx_info->has_dual_banks = false;
 
        return ERROR_OK;
 }
@@ -213,45 +214,35 @@ static int stm32lx_protect(struct flash_bank *bank, int set, int first,
 static int stm32lx_write_half_pages(struct flash_bank *bank, uint8_t *buffer,
                uint32_t offset, uint32_t count)
 {
-       struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        struct target *target = bank->target;
-       uint32_t buffer_size = 4096 * 4;
+       uint32_t buffer_size = 16384;
+       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[3];
        struct armv7m_algorithm armv7m_info;
 
        int retval = ERROR_OK;
-       uint32_t reg32;
-
-       /* see contib/loaders/flash/stm32lx.s for src */
 
-       static const uint16_t stm32lx_flash_write_code_16[] = {
-       /*      00000000 <write_word-0x4>: */
-                       0x2300, /* 0:   2300            movs    r3, #0 */
-                       0xe004, /* 2:   e004            b.n     e <test_done> */
+       /* see contib/loaders/flash/stm32lx.S for src */
 
-                       /*      00000004 <write_word>: */
-                       0xf851, 0xcb04, /* 4:   f851 cb04       ldr.w   ip, [r1], #4 */
-                       0xf840, 0xcb04, /* 8:   f840 cb04       str.w   ip, [r0], #4 */
-                       0x3301, /* c:   3301            adds    r3, #1 */
+       static const uint8_t stm32lx_flash_write_code[] = {
+               /* write_word: */
+               0x00, 0x23,             /* movs r3, #0 */
+               0x04, 0xe0,             /* b test_done */
 
-                       /*      0000000e <test_done>: */
-                       0x4293, /* e:   4293            cmp     r3, r2 */
-                       0xd3f8, /* 10:  d3f8            bcc.n   4 <write_word> */
-                       0xbe00, /* 12:  be00            bkpt    0x0000 */
+               /* write_word: */
+               0x51, 0xf8, 0x04, 0xcb, /* ldr ip, [r1], #4 */
+               0x40, 0xf8, 0x04, 0xcb, /* str ip, [r0], #4 */
+               0x01, 0x33,             /* adds r3, #1 */
 
-                       };
+               /* test_done: */
+               0x93, 0x42,             /* cmp r3, r2 */
+               0xf8, 0xd3,             /* bcc write_word */
+               0x00, 0xbe,             /* bkpt 0 */
+       };
 
-       /* Flip endian */
-       uint8_t stm32lx_flash_write_code[sizeof(stm32lx_flash_write_code_16)];
-       for (unsigned int i = 0; i < sizeof(stm32lx_flash_write_code_16) / 2; i++) {
-               stm32lx_flash_write_code[i * 2 + 0] = stm32lx_flash_write_code_16[i]
-                               & 0xff;
-               stm32lx_flash_write_code[i * 2 + 1] = (stm32lx_flash_write_code_16[i]
-                               >> 8) & 0xff;
-       }
        /* Check if there is an even number of half pages (128bytes) */
        if (count % 128) {
                LOG_ERROR("there should be an even number "
@@ -259,74 +250,77 @@ static int stm32lx_write_half_pages(struct flash_bank *bank, uint8_t *buffer,
                return ERROR_FAIL;
        }
 
-       /* Allocate working area */
-       reg32 = sizeof(stm32lx_flash_write_code);
-       /* Add bytes to make 4byte aligned */
-       reg32 += (4 - (reg32 % 4)) % 4;
-       retval = target_alloc_working_area(target, reg32,
-                       &stm32lx_info->write_algorithm);
-       if (retval != ERROR_OK)
-               return retval;
+       /* flash write code */
+       if (target_alloc_working_area(target, sizeof(stm32lx_flash_write_code),
+                       &write_algorithm) != ERROR_OK) {
+               LOG_DEBUG("no working area for block memory writes");
+               return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
+       };
 
        /* Write the flashing code */
        retval = target_write_buffer(target,
-                       stm32lx_info->write_algorithm->address,
+                       write_algorithm->address,
                        sizeof(stm32lx_flash_write_code),
                        (uint8_t *)stm32lx_flash_write_code);
        if (retval != ERROR_OK) {
-               target_free_working_area(target, stm32lx_info->write_algorithm);
+               target_free_working_area(target, write_algorithm);
                return retval;
        }
 
        /* Allocate half pages memory */
-       while (target_alloc_working_area_try(target, buffer_size, &source)
-                       != ERROR_OK) {
+       while (target_alloc_working_area_try(target, buffer_size, &source) != ERROR_OK) {
                if (buffer_size > 1024)
                        buffer_size -= 1024;
                else
                        buffer_size /= 2;
 
                if (buffer_size <= 256) {
-                       /* if we already allocated the writing code, but failed to get a
+                       /* we already allocated the writing code, but failed to get a
                         * buffer, free the algorithm */
-                       if (stm32lx_info->write_algorithm)
-                               target_free_working_area(target, stm32lx_info->write_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;
                }
        }
-       LOG_DEBUG("allocated working area for data (%" PRIx32 " bytes)", buffer_size);
 
        armv7m_info.common_magic = ARMV7M_COMMON_MAGIC;
-       armv7m_info.core_mode = ARMV7M_MODE_ANY;
+       armv7m_info.core_mode = ARM_MODE_THREAD;
        init_reg_param(&reg_params[0], "r0", 32, PARAM_OUT);
        init_reg_param(&reg_params[1], "r1", 32, PARAM_OUT);
        init_reg_param(&reg_params[2], "r2", 32, PARAM_OUT);
-       init_reg_param(&reg_params[3], "r3", 32, PARAM_IN_OUT);
-       init_reg_param(&reg_params[4], "r4", 32, PARAM_OUT);
 
        /* Enable half-page write */
        retval = stm32lx_enable_write_half_page(bank);
        if (retval != ERROR_OK) {
                target_free_working_area(target, source);
-               target_free_working_area(target, stm32lx_info->write_algorithm);
+               target_free_working_area(target, write_algorithm);
 
                destroy_reg_param(&reg_params[0]);
                destroy_reg_param(&reg_params[1]);
                destroy_reg_param(&reg_params[2]);
-               destroy_reg_param(&reg_params[3]);
                return retval;
        }
 
+       struct armv7m_common *armv7m = target_to_armv7m(target);
+       if (armv7m == NULL) {
+
+               /* something is very wrong if armv7m is NULL */
+               LOG_ERROR("unable to get armv7m target");
+               return retval;
+       }
+
+       /* save any DEMCR flags and configure target to catch any Hard Faults */
+       uint32_t demcr_save = armv7m->demcr;
+       armv7m->demcr = VC_HARDERR;
+
        /* Loop while there are bytes to write */
        while (count > 0) {
                uint32_t this_count;
                this_count = (count > buffer_size) ? buffer_size : count;
 
                /* Write the next half pages */
-               retval = target_write_buffer(target, source->address, this_count,
-                               buffer);
+               retval = target_write_buffer(target, source->address, this_count, buffer);
                if (retval != ERROR_OK)
                        break;
 
@@ -341,10 +335,14 @@ static int stm32lx_write_half_pages(struct flash_bank *bank, uint8_t *buffer,
                /* 5: Execute the bunch of code */
                retval = target_run_algorithm(target, 0, NULL, sizeof(reg_params)
                                / sizeof(*reg_params), reg_params,
-                               stm32lx_info->write_algorithm->address, 0, 20000, &armv7m_info);
+                               write_algorithm->address, 0, 10000, &armv7m_info);
                if (retval != ERROR_OK)
                        break;
 
+               /* check for Hard Fault */
+               if (armv7m->exception_number == 3)
+                       break;
+
                /* 6: Wait while busy */
                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
@@ -355,105 +353,163 @@ static int stm32lx_write_half_pages(struct flash_bank *bank, uint8_t *buffer,
                count -= this_count;
        }
 
+       /* restore previous flags */
+       armv7m->demcr = demcr_save;
+
+       if (armv7m->exception_number == 3) {
+
+               /* the stm32l15x devices seem to have an issue when blank.
+                * if a ram loader is executed on a blank device it will
+                * Hard Fault, this issue does not happen for a already programmed device.
+                * A related issue is described in the stm32l151xx errata (Doc ID 17721 Rev 6 - 2.1.3).
+                * The workaround of handling the Hard Fault exception does work, but makes the
+                * loader more complicated, as a compromise we manually write the pages, programming time
+                * is reduced by 50% using this slower method.
+                */
+
+               LOG_WARNING("couldn't use loader, falling back to page memory writes");
+
+               while (count > 0) {
+                       uint32_t this_count;
+                       this_count = (count > 128) ? 128 : count;
+
+                       /* Write the next half pages */
+                       retval = target_write_buffer(target, address, this_count, buffer);
+                       if (retval != ERROR_OK)
+                               break;
+
+                       /* Wait while busy */
+                       retval = stm32lx_wait_until_bsy_clear(bank);
+                       if (retval != ERROR_OK)
+                               break;
+
+                       buffer += this_count;
+                       address += this_count;
+                       count -= this_count;
+               }
+       }
+
        if (retval == ERROR_OK)
                retval = stm32lx_lock_program_memory(bank);
 
        target_free_working_area(target, source);
-       target_free_working_area(target, stm32lx_info->write_algorithm);
+       target_free_working_area(target, write_algorithm);
 
        destroy_reg_param(&reg_params[0]);
        destroy_reg_param(&reg_params[1]);
        destroy_reg_param(&reg_params[2]);
-       destroy_reg_param(&reg_params[3]);
 
        return retval;
 }
+
 static int stm32lx_write(struct flash_bank *bank, uint8_t *buffer,
                uint32_t offset, uint32_t count)
 {
        struct target *target = bank->target;
 
        uint32_t halfpages_number;
-       uint32_t words_remaining;
-       uint32_t bytes_remaining;
+       uint32_t bytes_remaining = 0;
        uint32_t address = bank->base + offset;
        uint32_t bytes_written = 0;
-       int retval;
+       int retval, retval2;
 
        if (bank->target->state != TARGET_HALTED) {
                LOG_ERROR("Target not halted");
                return ERROR_TARGET_NOT_HALTED;
        }
 
-       if (offset & 0x1) {
-               LOG_ERROR("offset 0x%" PRIx32 " breaks required 2-byte alignment", offset);
+       if (offset & 0x3) {
+               LOG_ERROR("offset 0x%" PRIx32 " breaks required 4-byte alignment", offset);
                return ERROR_FLASH_DST_BREAKS_ALIGNMENT;
        }
 
-       /* Check if there are some full half pages */
-       if (((offset % 128) == 0) && (count >= 128)) {
-               halfpages_number = count / 128;
-               words_remaining = (count - 128 * halfpages_number) / 4;
-               bytes_remaining = (count & 0x3);
-       } else {
-               halfpages_number = 0;
-               words_remaining = (count / 4);
-               bytes_remaining = (count & 0x3);
-       }
-
-       if (halfpages_number) {
-               retval = stm32lx_write_half_pages(bank, buffer, offset, 128
-                               * halfpages_number);
-               if (retval != ERROR_OK)
-                       return ERROR_FAIL;
-       }
-
-       bytes_written = 128 * halfpages_number;
-
        retval = stm32lx_unlock_program_memory(bank);
        if (retval != ERROR_OK)
                return retval;
 
-       while (words_remaining > 0) {
-               uint32_t value;
-               uint8_t *p = buffer + bytes_written;
+       /* first we need to write any unaligned head bytes upto
+        * the next 128 byte page */
+
+       if (offset % 128)
+               bytes_remaining = MIN(count, 128 - (offset % 128));
 
-               /* Prepare the word, Little endian conversion */
-               value = p[0] + (p[1] << 8) + (p[2] << 16) + (p[3] << 24);
+       while (bytes_remaining > 0) {
+               uint8_t value[4] = {0xff, 0xff, 0xff, 0xff};
 
-               retval = target_write_u32(target, address, value);
+               /* copy remaining bytes into the write buffer */
+               uint32_t bytes_to_write = MIN(4, bytes_remaining);
+               memcpy(value, buffer + bytes_written, bytes_to_write);
+
+               retval = target_write_buffer(target, address, 4, value);
                if (retval != ERROR_OK)
-                       return retval;
+                       goto reset_pg_and_lock;
 
-               bytes_written += 4;
-               words_remaining--;
+               bytes_written += bytes_to_write;
+               bytes_remaining -= bytes_to_write;
                address += 4;
 
                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
-                       return retval;
+                       goto reset_pg_and_lock;
+       }
+
+       offset += bytes_written;
+       count -= bytes_written;
+
+       /* this should always pass this check here */
+       assert((offset % 128) == 0);
+
+       /* calculate half pages */
+       halfpages_number = count / 128;
+
+       if (halfpages_number) {
+               retval = stm32lx_write_half_pages(bank, buffer + bytes_written, offset, 128 * halfpages_number);
+               if (retval == ERROR_TARGET_RESOURCE_NOT_AVAILABLE) {
+                       /* attempt slow memory writes */
+                       LOG_WARNING("couldn't use block writes, falling back to single memory accesses");
+                       halfpages_number = 0;
+               } else {
+                       if (retval != ERROR_OK)
+                               return ERROR_FAIL;
+               }
        }
 
-       if (bytes_remaining) {
-               uint8_t last_word[4] = {0xff, 0xff, 0xff, 0xff};
+       /* write any remaining bytes */
+       uint32_t page_bytes_written = 128 * halfpages_number;
+       bytes_written += page_bytes_written;
+       address += page_bytes_written;
+       bytes_remaining = count - page_bytes_written;
+
+       retval = stm32lx_unlock_program_memory(bank);
+       if (retval != ERROR_OK)
+               return retval;
 
-               /* copy the last remaining bytes into the write buffer */
-               memcpy(last_word, buffer+bytes_written, bytes_remaining);
+       while (bytes_remaining > 0) {
+               uint8_t value[4] = {0xff, 0xff, 0xff, 0xff};
 
-               retval = target_write_buffer(target, address, 4, last_word);
+               /* copy remaining bytes into the write buffer */
+               uint32_t bytes_to_write = MIN(4, bytes_remaining);
+               memcpy(value, buffer + bytes_written, bytes_to_write);
+
+               retval = target_write_buffer(target, address, 4, value);
                if (retval != ERROR_OK)
-                       return retval;
+                       goto reset_pg_and_lock;
+
+               bytes_written += bytes_to_write;
+               bytes_remaining -= bytes_to_write;
+               address += 4;
 
                retval = stm32lx_wait_until_bsy_clear(bank);
                if (retval != ERROR_OK)
-                       return retval;
+                       goto reset_pg_and_lock;
        }
 
-       retval = stm32lx_lock_program_memory(bank);
-       if (retval != ERROR_OK)
-               return retval;
+reset_pg_and_lock:
+       retval2 = stm32lx_lock_program_memory(bank);
+       if (retval == ERROR_OK)
+               retval = retval2;
 
-       return ERROR_OK;
+       return retval;
 }
 
 static int stm32lx_probe(struct flash_bank *bank)
@@ -461,9 +517,12 @@ static int stm32lx_probe(struct flash_bank *bank)
        struct target *target = bank->target;
        struct stm32lx_flash_bank *stm32lx_info = bank->driver_priv;
        int i;
-       uint16_t flash_size;
+       uint16_t flash_size_in_kb;
+       uint16_t max_flash_size_in_kb;
        uint32_t device_id;
-       uint32_t reg32;
+       uint32_t base_address = FLASH_BANK0_ADDRESS;
+       uint32_t second_bank_base;
+       uint32_t first_bank_size_in_kb;
 
        stm32lx_info->probed = 0;
 
@@ -474,95 +533,84 @@ static int stm32lx_probe(struct flash_bank *bank)
 
        LOG_DEBUG("device id = 0x%08" PRIx32 "", device_id);
 
-       if ((device_id & 0xfff) != 0x416) {
+       /* set max flash size depending on family */
+       switch (device_id & 0xfff) {
+       case 0x416:
+               max_flash_size_in_kb = 128;
+               break;
+       case 0x436:
+               /* According to ST, the devices with id 0x436 have dual bank flash and comes with
+                * a total flash size of 384k or 256kb. However, the first bank is always 192kb,
+                * and second one holds the rest. The reason is that the 256kb version is actually
+                * the same physical flash but only the first 256kb are verified.
+                */
+               max_flash_size_in_kb = 384;
+               first_bank_size_in_kb = 192;
+               stm32lx_info->has_dual_banks = true;
+               break;
+       default:
                LOG_WARNING("Cannot identify target as a STM32L family.");
                return ERROR_FAIL;
        }
 
-       /* Read the RDP byte and check if it is 0xAA */
-       uint8_t rdp;
-       retval = target_read_u32(target, FLASH_OBR, &reg32);
-       if (retval != ERROR_OK)
-               return retval;
-       rdp = reg32 & 0xFF;
-       if (rdp != 0xAA) {
-               /*
-                * Unlocking the option byte is done by unlocking the PECR, then
-                * by writing the 2 option byte keys to OPTKEYR
-                */
-
-               /* To unlock the PECR write the 2 PEKEY to the PEKEYR register */
-               retval = target_write_u32(target, FLASH_PEKEYR, PEKEY1);
-               if (retval != ERROR_OK)
-                       return retval;
-
-               retval = target_write_u32(target, FLASH_PEKEYR, PEKEY2);
-               if (retval != ERROR_OK)
-                       return retval;
-
-               /* Make sure it worked */
-               retval = target_read_u32(target, FLASH_PECR, &reg32);
-               if (retval != ERROR_OK)
-                       return retval;
-
-               if (reg32 & FLASH_PECR__PELOCK)
-                       return ERROR_FLASH_OPERATION_FAILED;
-
-               retval = target_write_u32(target, FLASH_OPTKEYR, OPTKEY1);
-               if (retval != ERROR_OK)
-                       return retval;
-               retval = target_write_u32(target, FLASH_OPTKEYR, OPTKEY2);
-               if (retval != ERROR_OK)
-                       return retval;
+       /* Get the flash size from target. */
+       retval = target_read_u16(target, F_SIZE, &flash_size_in_kb);
 
-               retval = target_read_u32(target, FLASH_PECR, &reg32);
-               if (retval != ERROR_OK)
-                       return retval;
+       /* 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) {
+               LOG_WARNING("STM32L flash size failed, probe inaccurate - assuming %dk flash",
+                       max_flash_size_in_kb);
+               flash_size_in_kb = max_flash_size_in_kb;
+       } else if (flash_size_in_kb > max_flash_size_in_kb) {
+               LOG_WARNING("STM32L probed flash size assumed incorrect since FLASH_SIZE=%dk > %dk, - assuming %dk flash",
+                       flash_size_in_kb, max_flash_size_in_kb, max_flash_size_in_kb);
+               flash_size_in_kb = max_flash_size_in_kb;
+       }
 
-               if (reg32 & FLASH_PECR__OPTLOCK) {
-                       LOG_ERROR("OPTLOCK is not cleared");
-                       return ERROR_FLASH_OPERATION_FAILED;
+       if (stm32lx_info->has_dual_banks) {
+               /* Use the configured base address to determine if this is the first or second flash bank.
+                * Verify that the base address is reasonably correct and determine the flash bank size
+                */
+               second_bank_base = base_address + first_bank_size_in_kb * 1024;
+               if (bank->base == second_bank_base) {
+                       /* This is the second bank  */
+                       base_address = second_bank_base;
+                       flash_size_in_kb = flash_size_in_kb - first_bank_size_in_kb;
+               } else if (bank->base == 0 || bank->base == base_address) {
+                       /* This is the first bank */
+                       flash_size_in_kb = first_bank_size_in_kb;
+               } else {
+                       LOG_WARNING("STM32L flash bank base address config is incorrect. 0x%x but should rather be 0x%x or 0x%x",
+                                               bank->base, base_address, second_bank_base);
+                       return ERROR_FAIL;
                }
-
-               /* Then, write RDP to 0x00 to set level 1 */
-               reg32 = ((~0xAA) << 16) | (0xAA);
-               retval = target_write_u32(target, OB_RDP, reg32);
-               if (retval != ERROR_OK)
-                       return retval;
-
-               /* Set Automatic update of the option byte, by setting OBL_LAUNCH in FLASH_PECR */
-               reg32 = FLASH_PECR__OBL_LAUNCH;
-               retval = target_write_u32(target, FLASH_PECR, reg32);
-               if (retval != ERROR_OK)
-                       return retval;
+               LOG_INFO("STM32L flash has dual banks. Bank (%d) size is %dkb, base address is 0x%x",
+                               bank->bank_number, flash_size_in_kb, base_address);
+       } else {
+               LOG_INFO("STM32L flash size is %dkb, base address is 0x%x", flash_size_in_kb, base_address);
        }
 
-       /* get flash size from target. */
-       retval = target_read_u16(target, F_SIZE, &flash_size);
-       if (retval != ERROR_OK)
-               return retval;
-
-       /* check for valid flash size */
-       if (flash_size == 0xffff) {
-               /* number of sectors incorrect on revA */
-               LOG_ERROR("STM32 flash size failed, probe inaccurate");
-               return ERROR_FAIL;
+       /* 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 (bank->size) {
+               flash_size_in_kb = bank->size / 1024;
+               LOG_INFO("ignoring flash probed value, using configured bank size: %dkbytes", flash_size_in_kb);
        }
 
        /* STM32L - we have 32 sectors, 16 pages per sector -> 512 pages
         * 16 pages for a protection area */
 
        /* calculate numbers of sectors (4kB per sector) */
-       int num_sectors = (flash_size * 1024) / FLASH_SECTOR_SIZE;
-       LOG_INFO("flash size = %dkbytes", flash_size);
+       int num_sectors = (flash_size_in_kb * 1024) / FLASH_SECTOR_SIZE;
 
        if (bank->sectors) {
                free(bank->sectors);
                bank->sectors = NULL;
        }
 
-       bank->base = FLASH_BANK0_ADDRESS;
-       bank->size = flash_size * 1024;
+       bank->size = flash_size_in_kb * 1024;
+       bank->base = base_address;
        bank->num_sectors = num_sectors;
        bank->sectors = malloc(sizeof(struct flash_sector) * num_sectors);
        if (bank->sectors == NULL) {
@@ -668,6 +716,41 @@ static int stm32lx_get_info(struct flash_bank *bank, char *buf, int buf_size)
                        case 0x1008:
                                snprintf(buf, buf_size, "Y");
                                break;
+
+                       case 0x1018:
+                               snprintf(buf, buf_size, "X");
+                               break;
+
+                       case 0x1038:
+                               snprintf(buf, buf_size, "W");
+                               break;
+
+                       case 0x1078:
+                               snprintf(buf, buf_size, "V");
+                               break;
+
+                       default:
+                               snprintf(buf, buf_size, "unknown");
+                               break;
+               }
+       } else if ((device_id & 0xfff) == 0x436) {
+               printed = snprintf(buf, buf_size, "stm32lx (HD) - Rev: ");
+               buf += printed;
+               buf_size -= printed;
+
+               switch (device_id >> 16) {
+                       case 0x1000:
+                               snprintf(buf, buf_size, "A");
+                               break;
+
+                       case 0x1008:
+                               snprintf(buf, buf_size, "Z");
+                               break;
+
+                       case 0x1018:
+                               snprintf(buf, buf_size, "Y");
+                               break;
+
                        default:
                                snprintf(buf, buf_size, "unknown");
                                break;
@@ -722,6 +805,14 @@ static int stm32lx_unlock_program_memory(struct flash_bank *bank)
         * then by writing the 2 PRGKEY to the PRGKEYR register
         */
 
+       /* check flash is not already unlocked */
+       retval = target_read_u32(target, FLASH_PECR, &reg32);
+       if (retval != ERROR_OK)
+               return retval;
+
+       if ((reg32 & FLASH_PECR__PRGLOCK) == 0)
+               return ERROR_OK;
+
        /* To unlock the PECR write the 2 PEKEY to the PEKEYR register */
        retval = target_write_u32(target, FLASH_PEKEYR, PEKEY1);
        if (retval != ERROR_OK)
@@ -757,6 +848,7 @@ static int stm32lx_unlock_program_memory(struct flash_bank *bank)
                LOG_ERROR("PRGLOCK is not cleared :(");
                return ERROR_FLASH_OPERATION_FAILED;
        }
+
        return ERROR_OK;
 }