Merge pull request #1779 from dhalbert/nrf-nvm-2

nrf nvm: touchups to nickzoic PR #1768

12 files changed, 308 insertions, 78 deletions

diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 3cb4b52aa..b32b25217 100755
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -177,6 +177,7 @@ SRC_C += \
 	peripherals/nrf/clocks.c \
 	peripherals/nrf/$(MCU_CHIP)/pins.c \
 	peripherals/nrf/$(MCU_CHIP)/power.c \
+        peripherals/nrf/nvm.c \
 	peripherals/nrf/timers.c \
 	sd_mutex.c \
 	supervisor/shared/memory.c
diff --git a/ports/nrf/boards/adafruit_nrf52840_s140_v6.ld b/ports/nrf/boards/adafruit_nrf52840_s140_v6.ld
index 8a700d610..2587a19e3 100644
--- a/ports/nrf/boards/adafruit_nrf52840_s140_v6.ld
+++ b/ports/nrf/boards/adafruit_nrf52840_s140_v6.ld
@@ -11,7 +11,6 @@
 
     0x000ED000..0x000F3FFF (28KB ) Private Config Data (Bonding, Keys, etc.)
     0x000AD000..0x000ECFFF (256KB) User Filesystem
-
     0x00026000..0x000ACFFF (540KB) Application Code (including ISR vector)
     0x00001000..0x00025FFF (148KB) SoftDevice
     0x00000000..0x00000FFF   (4KB) Master Boot Record
diff --git a/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h b/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h
index eb8be7608..e1f43e3c9 100644
--- a/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h
+++ b/ports/nrf/boards/feather_nrf52840_express/mpconfigboard.h
@@ -33,6 +33,9 @@
 #define MICROPY_HW_MCU_NAME         "nRF52840"
 #define MICROPY_PY_SYS_PLATFORM     "Feather52840Express"
 
+#define FLASH_SIZE                  (0x100000)
+#define FLASH_PAGE_SIZE             (4096)
+
 #define MICROPY_HW_NEOPIXEL         (&pin_P0_16)
 
 #define MICROPY_HW_LED_STATUS       (&pin_P1_15)
@@ -55,7 +58,7 @@
 
 #define CIRCUITPY_AUTORELOAD_DELAY_MS 500
 
-// TODO #define CIRCUITPY_INTERNAL_NVM_SIZE 8192
+#define CIRCUITPY_INTERNAL_NVM_SIZE (4096)
 
 #define BOARD_FLASH_SIZE (FLASH_SIZE - 0x4000 - CIRCUITPY_INTERNAL_NVM_SIZE)
 
diff --git a/ports/nrf/common-hal/microcontroller/__init__.c b/ports/nrf/common-hal/microcontroller/__init__.c
index c2e0c5b41..92aac772a 100644
--- a/ports/nrf/common-hal/microcontroller/__init__.c
+++ b/ports/nrf/common-hal/microcontroller/__init__.c
@@ -24,9 +24,14 @@
  * THE SOFTWARE.
  */
 
+#include "py/mphal.h"
+#include "py/obj.h"
+#include "py/runtime.h"
+
 #include "common-hal/microcontroller/Pin.h"
 #include "common-hal/microcontroller/Processor.h"
 
+#include "shared-bindings/nvm/ByteArray.h"
 #include "shared-bindings/microcontroller/__init__.h"
 #include "shared-bindings/microcontroller/Pin.h"
 #include "shared-bindings/microcontroller/Processor.h"
@@ -63,6 +68,16 @@ const mcu_processor_obj_t common_hal_mcu_processor_obj = {
     },
 };
 
+#if CIRCUITPY_INTERNAL_NVM_SIZE > 0
+// The singleton nvm.ByteArray object.
+const nvm_bytearray_obj_t common_hal_mcu_nvm_obj = {
+    .base = {
+        .type = &nvm_bytearray_type,
+    },
+    .len = CIRCUITPY_INTERNAL_NVM_SIZE,
+    .start_address = (uint8_t*) (FLASH_SIZE - CIRCUITPY_INTERNAL_NVM_SIZE),
+};
+#endif
 
 STATIC const mp_rom_map_elem_t mcu_pin_globals_table[] = {
   { MP_ROM_QSTR(MP_QSTR_P0_00), MP_ROM_PTR(&pin_P0_00) },
diff --git a/ports/nrf/common-hal/nvm/ByteArray.c b/ports/nrf/common-hal/nvm/ByteArray.c
new file mode 100644
index 000000000..4373e2502
--- /dev/null
+++ b/ports/nrf/common-hal/nvm/ByteArray.c
@@ -0,0 +1,77 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Nick Moore for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "common-hal/nvm/ByteArray.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include "peripherals/nrf/nvm.h"
+
+// defined in linker
+extern uint32_t __fatfs_flash_start_addr[];
+extern uint32_t __fatfs_flash_length[];
+
+uint32_t common_hal_nvm_bytearray_get_length(nvm_bytearray_obj_t *self) {
+    return self->len;
+}
+
+static void write_page(uint8_t* page_addr, uint32_t offset, uint32_t len, uint8_t *bytes) {
+    // Write a whole page to flash, buffering it first and then erasing and rewriting
+    // it since we can only clear a whole page at a time.
+
+    if (offset == 0 && len == FLASH_PAGE_SIZE) {
+        nrf_nvm_safe_flash_page_write((uint32_t) page_addr, bytes);
+    } else {
+        uint8_t buffer[FLASH_PAGE_SIZE];
+        memcpy(buffer, page_addr, FLASH_PAGE_SIZE);
+        memcpy(buffer + offset, bytes, len);
+        nrf_nvm_safe_flash_page_write((uint32_t) page_addr, buffer);
+    }
+}
+
+bool common_hal_nvm_bytearray_set_bytes(nvm_bytearray_obj_t *self,
+        uint32_t start_index, uint8_t* values, uint32_t len) {
+
+    uint32_t address = ((uint32_t) self->start_address) + start_index;
+    uint32_t offset = address % FLASH_PAGE_SIZE;
+    uint32_t page_addr = address - offset;
+
+    while (len) {
+        uint32_t write_len = MIN(len, FLASH_PAGE_SIZE - offset);
+        write_page((uint8_t*) page_addr, offset, write_len, values);
+        len -= write_len;
+        values += write_len;
+        page_addr += FLASH_PAGE_SIZE;
+        offset = 0;
+    }
+    return true;
+}
+
+void common_hal_nvm_bytearray_get_bytes(nvm_bytearray_obj_t *self,
+        uint32_t start_index, uint32_t len, uint8_t* values) {
+    memcpy(values, self->start_address + start_index, len);
+}
diff --git a/ports/nrf/common-hal/nvm/ByteArray.h b/ports/nrf/common-hal/nvm/ByteArray.h
new file mode 100644
index 000000000..c048d5577
--- /dev/null
+++ b/ports/nrf/common-hal/nvm/ByteArray.h
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Nick Moore for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_NRF_COMMON_HAL_NVM_BYTEARRAY_H
+#define MICROPY_INCLUDED_NRF_COMMON_HAL_NVM_BYTEARRAY_H
+
+#include "py/obj.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    uint8_t* start_address;
+    uint32_t len;
+} nvm_bytearray_obj_t;
+
+#endif // MICROPY_INCLUDED_NRF_COMMON_HAL_NVM_BYTEARRAY_H
diff --git a/ports/nrf/common-hal/nvm/__init__.c b/ports/nrf/common-hal/nvm/__init__.c
new file mode 100644
index 000000000..3cdc9d3a4
--- /dev/null
+++ b/ports/nrf/common-hal/nvm/__init__.c
@@ -0,0 +1,27 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Nick Moore for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// No nvm module functions.
diff --git a/ports/nrf/mpconfigport.mk b/ports/nrf/mpconfigport.mk
index fdeb1bbbe..83166708a 100644
--- a/ports/nrf/mpconfigport.mk
+++ b/ports/nrf/mpconfigport.mk
@@ -19,8 +19,8 @@ CIRCUITPY_AUDIOBUSIO = 0
 # No I2CSlave implementation
 CIRCUITPY_I2CSLAVE = 0
 
-# nvm not yet implemented
-CIRCUITPY_NVM = 0
+# enable NVM
+CIRCUITPY_NVM = 1
 
 # enable RTC
 CIRCUITPY_RTC = 1
diff --git a/ports/nrf/peripherals/nrf/nvm.c b/ports/nrf/peripherals/nrf/nvm.c
new file mode 100644
index 000000000..d8fddc4dc
--- /dev/null
+++ b/ports/nrf/peripherals/nrf/nvm.c
@@ -0,0 +1,95 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013, 2014 Damien P. George
+ * Copyright (c) 2019 Nick Moore for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include "nrf_nvmc.h"
+
+#define FLASH_PAGE_SIZE (4096)
+
+#ifdef BLUETOOTH_SD
+#include "ble_drv.h"
+#include "nrf_sdm.h"
+
+STATIC void sd_flash_operation_start(void) {
+    sd_flash_operation_status = SD_FLASH_OPERATION_IN_PROGRESS;
+}
+
+STATIC sd_flash_operation_status_t sd_flash_operation_wait_until_done(void) {
+    while (sd_flash_operation_status == SD_FLASH_OPERATION_IN_PROGRESS) {
+        sd_app_evt_wait();
+    }
+    return sd_flash_operation_status;
+}
+#endif
+
+void nrf_nvm_safe_flash_page_write(uint32_t page_addr, uint8_t *data) {
+    #ifdef BLUETOOTH_SD
+        uint8_t sd_en = 0;
+        (void) sd_softdevice_is_enabled(&sd_en);
+        if (sd_en) {
+            uint32_t err_code;
+            sd_flash_operation_status_t status;
+
+            sd_flash_operation_start();
+            err_code = sd_flash_page_erase(page_addr / FLASH_PAGE_SIZE);
+            if (err_code != NRF_SUCCESS) {
+                mp_raise_OSError_msg_varg(translate("Flash erase failed to start, err 0x%04x"), err_code);
+            }
+            status = sd_flash_operation_wait_until_done();
+            if (status == SD_FLASH_OPERATION_ERROR) {
+                mp_raise_OSError_msg(translate("Flash erase failed"));
+            }
+
+            // Divide a full page into parts, because writing a full page causes an assertion failure.
+            // See https://devzone.nordicsemi.com/f/nordic-q-a/40088/sd_flash_write-cause-nrf_fault_id_sd_assert/
+            const size_t BLOCK_PARTS = 2;
+            size_t words_to_write = FLASH_PAGE_SIZE / sizeof(uint32_t) / BLOCK_PARTS;
+            for (size_t i = 0; i < BLOCK_PARTS; i++) {
+                sd_flash_operation_start();
+                err_code = sd_flash_write(((uint32_t *)page_addr) + i * words_to_write,
+                                          (uint32_t *)data + i * words_to_write,
+                                          words_to_write);
+                if (err_code != NRF_SUCCESS) {
+                    mp_raise_OSError_msg_varg(translate("Flash write failed to start, err 0x%04x"), err_code);
+                }
+                status = sd_flash_operation_wait_until_done();
+                if (status == SD_FLASH_OPERATION_ERROR) {
+                    mp_raise_OSError_msg(translate("Flash write failed"));
+                }
+            }
+
+            return;
+        }
+    #endif
+
+    nrf_nvmc_page_erase(page_addr);
+    nrf_nvmc_write_bytes(page_addr, data, FLASH_PAGE_SIZE);
+}    
diff --git a/ports/nrf/peripherals/nrf/nvm.h b/ports/nrf/peripherals/nrf/nvm.h
new file mode 100644
index 000000000..4eac3d728
--- /dev/null
+++ b/ports/nrf/peripherals/nrf/nvm.h
@@ -0,0 +1,34 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013, 2014 Damien P. George
+ * Copyright (c) 2019 Nick Moore for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#define FLASH_PAGE_SIZE (4096)
+
+#ifndef CIRCUITPY_INTERNAL_NVM_SIZE
+#define CIRCUITPY_INTERNAL_NVM_SIZE (0)
+#endif
+
+void nrf_nvm_safe_flash_page_write(uint32_t page_addr, uint8_t *data);
diff --git a/ports/nrf/supervisor/internal_flash.c b/ports/nrf/supervisor/internal_flash.c
index c18b708a3..5713dea88 100644
--- a/ports/nrf/supervisor/internal_flash.c
+++ b/ports/nrf/supervisor/internal_flash.c
@@ -35,7 +35,7 @@
 #include "py/runtime.h"
 #include "lib/oofatfs/ff.h"
 
-#include "nrf_nvmc.h"
+#include "peripherals/nrf/nvm.h"
 
 #ifdef BLUETOOTH_SD
 #include "ble_drv.h"
@@ -47,9 +47,8 @@ extern uint32_t __fatfs_flash_start_addr[];
 extern uint32_t __fatfs_flash_length[];
 
 #define NO_CACHE        0xffffffff
-#define FL_PAGE_SZ      4096
 
-uint8_t  _flash_cache[FL_PAGE_SZ] __attribute__((aligned(4)));
+uint8_t  _flash_cache[FLASH_PAGE_SIZE] __attribute__((aligned(4)));
 uint32_t _flash_page_addr = NO_CACHE;
 
 
@@ -68,81 +67,22 @@ uint32_t supervisor_flash_get_block_size(void) {
 }
 
 uint32_t supervisor_flash_get_block_count(void) {
-    return ((uint32_t) __fatfs_flash_length) / FILESYSTEM_BLOCK_SIZE ;
+    return ((uint32_t) __fatfs_flash_length - CIRCUITPY_INTERNAL_NVM_SIZE) / FILESYSTEM_BLOCK_SIZE ;
 }
 
-#ifdef BLUETOOTH_SD
-STATIC void sd_flash_operation_start(void) {
-    sd_flash_operation_status = SD_FLASH_OPERATION_IN_PROGRESS;
-}
-
-STATIC sd_flash_operation_status_t sd_flash_operation_wait_until_done(void) {
-    while (sd_flash_operation_status == SD_FLASH_OPERATION_IN_PROGRESS) {
-        sd_app_evt_wait();
-    }
-    return sd_flash_operation_status;
-}
-#endif
-
 void supervisor_flash_flush(void) {
     if (_flash_page_addr == NO_CACHE) return;
 
     // Skip if data is the same
-    if (memcmp(_flash_cache, (void *)_flash_page_addr, FL_PAGE_SZ) != 0) {
-
-#ifdef BLUETOOTH_SD
-        uint8_t sd_en = 0;
-        (void) sd_softdevice_is_enabled(&sd_en);
-
-        if (sd_en) {
-            uint32_t err_code;
-            sd_flash_operation_status_t status;
-
-            sd_flash_operation_start();
-            err_code = sd_flash_page_erase(_flash_page_addr / FL_PAGE_SZ);
-            if (err_code != NRF_SUCCESS) {
-                mp_raise_OSError_msg_varg(translate("Flash erase failed to start, err 0x%04x"), err_code);
-            }
-            status = sd_flash_operation_wait_until_done();
-            if (status == SD_FLASH_OPERATION_ERROR) {
-                mp_raise_OSError_msg(translate("Flash erase failed"));
-            }
-
-            // Divide a full page into parts, because writing a full page causes an assertion failure.
-            // See https://devzone.nordicsemi.com/f/nordic-q-a/40088/sd_flash_write-cause-nrf_fault_id_sd_assert/
-            const size_t BLOCK_PARTS = 2;
-            size_t words_to_write = FL_PAGE_SZ / sizeof(uint32_t) / BLOCK_PARTS;
-            for (size_t i = 0; i < BLOCK_PARTS; i++) {
-                sd_flash_operation_start();
-                err_code = sd_flash_write(((uint32_t *)_flash_page_addr) + i * words_to_write,
-                                          (uint32_t *)_flash_cache + i * words_to_write,
-                                          words_to_write);
-                if (err_code != NRF_SUCCESS) {
-                    mp_raise_OSError_msg_varg(translate("Flash write failed to start, err 0x%04x"), err_code);
-                }
-                status = sd_flash_operation_wait_until_done();
-                if (status == SD_FLASH_OPERATION_ERROR) {
-                    mp_raise_OSError_msg(translate("Flash write failed"));
-                }
-            }
-        } else {
-#endif
-            nrf_nvmc_page_erase(_flash_page_addr);
-            nrf_nvmc_write_words(_flash_page_addr, (uint32_t *)_flash_cache, FL_PAGE_SZ / sizeof(uint32_t));
-#ifdef BLUETOOTH_SD
-        }
-#endif
-
+    if (memcmp(_flash_cache, (void *)_flash_page_addr, FLASH_PAGE_SIZE) != 0) {
+        nrf_nvm_safe_flash_page_write(_flash_page_addr, _flash_cache);
     }
-    _flash_page_addr = NO_CACHE;
-}
-
-void supervisor_flash_release_cache(void) {
 }
 
 mp_uint_t supervisor_flash_read_blocks(uint8_t *dest, uint32_t block, uint32_t num_blocks) {
     // Must write out anything in cache before trying to read.
     supervisor_flash_flush();
+
     uint32_t src = lba2addr(block);
     memcpy(dest, (uint8_t*) src, FILESYSTEM_BLOCK_SIZE*num_blocks);
     return 0; // success
@@ -151,21 +91,21 @@ mp_uint_t supervisor_flash_read_blocks(uint8_t *dest, uint32_t block, uint32_t n
 mp_uint_t supervisor_flash_write_blocks(const uint8_t *src, uint32_t lba, uint32_t num_blocks) {
     while (num_blocks) {
         uint32_t const addr      = lba2addr(lba);
-        uint32_t const page_addr = addr & ~(FL_PAGE_SZ - 1);
+        uint32_t const page_addr = addr & ~(FLASH_PAGE_SIZE - 1);
 
         uint32_t count = 8 - (lba % 8); // up to page boundary
         count = MIN(num_blocks, count);
 
         if (page_addr != _flash_page_addr) {
-            supervisor_flash_flush();
-
+            nrf_nvm_safe_flash_page_write(_flash_page_addr, _flash_cache);
             _flash_page_addr = page_addr;
+
             // Copy the current contents of the entire page into the cache.
-            memcpy(_flash_cache, (void *)page_addr, FL_PAGE_SZ);
+            memcpy(_flash_cache, (void *)page_addr, FLASH_PAGE_SIZE);
         }
 
         // Overwrite part or all of the page cache with the src data.
-        memcpy(_flash_cache + (addr & (FL_PAGE_SZ - 1)), src, count * FILESYSTEM_BLOCK_SIZE);
+        memcpy(_flash_cache + (addr & (FLASH_PAGE_SIZE - 1)), src, count * FILESYSTEM_BLOCK_SIZE);
 
         // adjust for next run
         lba        += count;
@@ -175,3 +115,7 @@ mp_uint_t supervisor_flash_write_blocks(const uint8_t *src, uint32_t lba, uint32
 
     return 0; // success
 }
+
+void supervisor_flash_release_cache(void) {
+}
+
diff --git a/ports/nrf/supervisor/internal_flash.h b/ports/nrf/supervisor/internal_flash.h
index cf1dc91b5..024a53ebb 100644
--- a/ports/nrf/supervisor/internal_flash.h
+++ b/ports/nrf/supervisor/internal_flash.h
@@ -31,9 +31,6 @@
 
 #include "py/mpconfig.h"
 
-#define FLASH_PAGE_SIZE                 0x1000
-#define CIRCUITPY_INTERNAL_NVM_SIZE     0
-
 #define INTERNAL_FLASH_SYSTICK_MASK     (0x1ff) // 512ms
 #define INTERNAL_FLASH_IDLE_TICK(tick)  (((tick) & INTERNAL_FLASH_SYSTICK_MASK) == 2)