atmel-samd: Add support for internal filesystems. (#311)

* atmel-samd: Add support for internal filesystems.

This allows us to re-enable `os`. `random` is also enabled because
it solely depends on `os`.

Fixes #266. Its also a pre-requisite for #260.

* atmel-samd: Update SAMD51 linker script comments and MICROPY_MAX_STACK_USAGE enabling.

37 files changed, 567 insertions, 114 deletions

diff --git a/atmel-samd/Makefile b/atmel-samd/Makefile
index 49bd08722..2c51342d5 100644
--- a/atmel-samd/Makefile
+++ b/atmel-samd/Makefile
@@ -79,18 +79,25 @@ BASE_CFLAGS = \
 	-fshort-enums \
 	--param max-inline-insns-single=500
 
+# NDEBUG disables assert() statements. This reduces code size pretty dramatically, per tannewt.
+ifeq ($(CHIP_FAMILY), samd21)
+CFLAGS = -Os -DNDEBUG -finline-limit=49
+endif
+ifeq ($(CHIP_FAMILY), samd51)
+CFLAGS = -O2 -DNDEBUG
+endif
+
 #Debugging/Optimization
 ifeq ($(DEBUG), 1)
-# NDEBUG disables assert() statements. This reduces code size pretty dramatically, per tannewt.
 # Turn on Python modules useful for debugging (e.g. uheap, ustack).
-CFLAGS = -O1 -ggdb -DNDEBUG
+CFLAGS += -ggdb
 ifeq ($(CHIP_FAMILY), samd21)
-CFLAGS += -DENABLE_MICRO_TRACE_BUFFER
+CFLAGS += -DNDEBUG -DENABLE_MICRO_TRACE_BUFFER
 endif
 else
 # -finline-limit can shrink the image size. -finline-limit=80 or so is similar to not having it on.
 # There is no simple default value, though.
-CFLAGS = -Os -DNDEBUG -flto -finline-limit=49
+CFLAGS += -DNDEBUG -flto -finline-limit=49
 endif
 
 CFLAGS += $(INC) -Wall -Werror -std=gnu11 -nostdlib $(BASE_CFLAGS) $(CFLAGS_MOD) $(COPT)
@@ -109,8 +116,9 @@ CFLAGS += \
 	-mthumb \
 	-mabi=aapcs-linux \
 	-mlong-calls \
+	-mtune=cortex-m4 \
 	-mcpu=cortex-m4 \
-	-mfloat-abi=softfp \
+	-mfloat-abi=hard \
 	-mfpu=fpv4-sp-d16 \
 	-DSAMD51
 endif
@@ -150,11 +158,13 @@ SRC_ASF := \
 	gcc/system_$(CHIP_FAMILY).c \
 	hal/src/hal_atomic.c \
 	hal/src/hal_delay.c \
+	hal/src/hal_flash.c \
 	hal/src/hal_sleep.c \
 	hal/src/hal_timer.c \
 	hal/src/hal_usb_device.c \
 	hpl/core/hpl_init.c \
 	hpl/gclk/hpl_gclk.c \
+	hpl/nvmctrl/hpl_nvmctrl.c \
 	hpl/pm/hpl_pm.c \
 	hpl/rtc/hpl_rtc.c \
 	hpl/systick/hpl_systick.c \
@@ -172,10 +182,12 @@ SRC_ASF += \
 
 else ifeq ($(CHIP_FAMILY), samd51)
 SRC_ASF += \
+    hal/src/hal_rand_sync.c \
 	hpl/core/hpl_core_m4.c \
 	hpl/mclk/hpl_mclk.c \
 	hpl/osc32kctrl/hpl_osc32kctrl.c \
 	hpl/oscctrl/hpl_oscctrl.c \
+	hpl/trng/hpl_trng.c \
 
 endif
 
@@ -184,7 +196,6 @@ SRC_ASF := $(addprefix asf4/$(CHIP_FAMILY)/, $(SRC_ASF))
 # Skip this source for now.
 #	access_vfs.c \
 	shared_dma.c \
-	$(FLASH_IMPL) \
 
 SRC_C = \
 	background.c \
@@ -195,6 +206,7 @@ SRC_C = \
 	$(CHIP_FAMILY)_pins.c \
 	tick.c \
 	usb.c \
+	$(FLASH_IMPL) \
 	bindings/samd/__init__.c \
 	boards/$(BOARD)/board.c \
 	boards/$(BOARD)/pins.c \
@@ -218,6 +230,7 @@ SRC_COMMON_HAL = \
 	microcontroller/__init__.c \
 	microcontroller/Pin.c \
 	microcontroller/Processor.c \
+	os/__init__.c \
 	time/__init__.c
 #	analogio/__init__.c \
 	analogio/AnalogIn.c \
@@ -233,7 +246,6 @@ SRC_COMMON_HAL = \
 	neopixel_write/__init__.c \
 	nvm/__init__.c \
 	nvm/ByteArray.c \
-	os/__init__.c \
 	pulseio/__init__.c \
 	pulseio/PulseIn.c \
 	pulseio/PulseOut.c \
diff --git a/atmel-samd/asf4/patches/samd21/cast-align.patch b/atmel-samd/asf4/patches/samd21/cast-align.patch
index 04ddf9bf5..2059867e4 100644
--- a/atmel-samd/asf4/patches/samd21/cast-align.patch
+++ b/atmel-samd/asf4/patches/samd21/cast-align.patch
@@ -10,3 +10,27 @@
 +        #pragma GCC diagnostic pop
  	struct timer_task *      it    = (struct timer_task *)list_get_head(&timer->tasks);
  	uint32_t                 time  = ++timer->time;
+--- a/hal/src/hal_flash.c
++++ b/hal/src/hal_flash.c
+@@ -304,7 +304,10 @@ static int32_t flash_is_address_aligned(struct flash_descriptor *flash, const ui
+  */
+ static void flash_ready(struct _flash_device *device)
+ {
++       #pragma GCC diagnostic push
++       #pragma GCC diagnostic ignored "-Wcast-align"
+        struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
++       #pragma GCC diagnostic pop
+        if (descr->callbacks.cb_ready) {
+                descr->callbacks.cb_ready(descr);
+        }
+@@ -317,7 +320,10 @@ static void flash_ready(struct _flash_device *device)
+  */
+ static void flash_error(struct _flash_device *device)
+ {
++       #pragma GCC diagnostic push
++       #pragma GCC diagnostic ignored "-Wcast-align"
+        struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
++       #pragma GCC diagnostic pop
+        if (descr->callbacks.cb_error) {
+                descr->callbacks.cb_error(descr);
+        }
diff --git a/atmel-samd/asf4/patches/samd21/flash-const.patch b/atmel-samd/asf4/patches/samd21/flash-const.patch
new file mode 100644
index 000000000..cac428ab3
--- /dev/null
+++ b/atmel-samd/asf4/patches/samd21/flash-const.patch
@@ -0,0 +1,61 @@
+--- a/hal/include/hal_flash.h
++++ b/hal/include/hal_flash.h
+@@ -132,7 +132,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
+  *  \param[in]  length    Number of bytes to append
+  *  \return Append status.
+  */
+-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length);
++int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
+
+ /** \brief Reads a number of bytes to a page in the internal Flash
+  *
+--- a/hal/include/hpl_flash.h
++++ b/hal/include/hpl_flash.h
+@@ -125,7 +125,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
+  *                           write is stored
+  * \param[in]  length        Number of bytes to write
+  */
+-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
++void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
+
+ /**
+  * \brief Appends a number of bytes in the internal Flash.
+@@ -135,7 +135,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
+  * \param[in]  buffer        Pointer to buffer with data to write to flash
+  * \param[in]  length        Number of bytes to write
+  */
+-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
++void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
+
+ /** \brief Execute lock in the internal flash
+  *  \param[in] device         The pointer to FLASH device instance
+--- a/hal/src/hal_flash.c
++++ b/hal/src/hal_flash.c
+@@ -135,7 +135,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
+ /**
+ * \brief Appends a number of bytes to a page in the internal Flash
+ */
+-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length)
++int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
+ {
+       ASSERT(flash && buffer && length);
+--- a/hpl/nvmctrl/hpl_nvmctrl.c
++++ b/hpl/nvmctrl/hpl_nvmctrl.c
+@@ -175,7 +175,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
+ /**
+  * \brief Writes a number of bytes to a page in the internal Flash.
+  */
+-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
++void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
+ {
+        uint8_t  tmp_buffer[NVMCTRL_ROW_PAGES][NVMCTRL_PAGE_SIZE];
+        uint32_t row_start_addr, row_end_addr;
+@@ -219,7 +219,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
+ /**
+  * \brief Appends a number of bytes in the internal Flash.
+  */
+-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
++void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
+ {
+        uint32_t page_start_addr = dst_addr & ~(NVMCTRL_PAGE_SIZE - 1);
+        uint32_t size;
diff --git a/atmel-samd/asf4/patches/samd51/array-bounds.patch b/atmel-samd/asf4/patches/samd51/array-bounds.patch
new file mode 100644
index 000000000..30f40cb79
--- /dev/null
+++ b/atmel-samd/asf4/patches/samd51/array-bounds.patch
@@ -0,0 +1,13 @@
+--- a/CMSIS/Include/core_cm4.h
++++ b/CMSIS/Include/core_cm4.h
+@@ -1493,8 +1493,12 @@ __STATIC_INLINE uint32_t NVIC_GetPriorityGrouping(void)
+  */
+ __STATIC_INLINE void NVIC_EnableIRQ(IRQn_Type IRQn)
+ {
++
++  #pragma GCC diagnostic push
++  #pragma GCC diagnostic ignored "-Warray-bounds"
+ /*  NVIC->ISER[((uint32_t)(IRQn) >> 5)] = (1 << ((uint32_t)(IRQn) & 0x1F));  enable interrupt */
+   NVIC->ISER[(uint32_t)((int32_t)IRQn) >> 5] = (uint32_t)(1 << ((uint32_t)((int32_t)IRQn) & (uint32_t)0x1F)); /* enable interrupt */
++  #pragma GCC diagnostic pop
+ }
diff --git a/atmel-samd/asf4/patches/samd51/cast-align.patch b/atmel-samd/asf4/patches/samd51/cast-align.patch
index 1418c9fb1..399c1ff80 100644
--- a/atmel-samd/asf4/patches/samd51/cast-align.patch
+++ b/atmel-samd/asf4/patches/samd51/cast-align.patch
@@ -10,3 +10,40 @@
 +	#pragma GCC diagnostic pop
  	struct timer_task *      it    = (struct timer_task *)list_get_head(&timer->tasks);
  	uint32_t                 time  = ++timer->time;
+
+--- a/hal/src/hal_flash.c
++++ b/hal/src/hal_flash.c
+@@ -304,7 +304,10 @@ static int32_t flash_is_address_aligned(struct flash_descriptor *flash, const ui
+  */
+ static void flash_ready(struct _flash_device *device)
+ {
++       #pragma GCC diagnostic push
++       #pragma GCC diagnostic ignored "-Wcast-align"
+        struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
++       #pragma GCC diagnostic pop
+        if (descr->callbacks.cb_ready) {
+                descr->callbacks.cb_ready(descr);
+        }
+@@ -317,7 +320,10 @@ static void flash_ready(struct _flash_device *device)
+  */
+ static void flash_error(struct _flash_device *device)
+ {
++       #pragma GCC diagnostic push
++       #pragma GCC diagnostic ignored "-Wcast-align"
+        struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
++       #pragma GCC diagnostic pop
+        if (descr->callbacks.cb_error) {
+                descr->callbacks.cb_error(descr);
+        }
+--- a/hpl/nvmctrl/hpl_nvmctrl.c
++++ b/hpl/nvmctrl/hpl_nvmctrl.c
+@@ -386,7 +386,10 @@ static void _flash_erase_block(void *const hw, const uint32_t dst_addr)
+  */
+ static void _flash_program(void *const hw, const uint32_t dst_addr, const uint8_t *buffer, const uint16_t size)
+ {
++       #pragma GCC diagnostic push
++       #pragma GCC diagnostic ignored "-Wcast-align"
+        uint32_t *ptr_read    = (uint32_t *)buffer;
++       #pragma GCC diagnostic pop
+        uint32_t  nvm_address = dst_addr / 4;
+        uint16_t  i;
diff --git a/atmel-samd/asf4/patches/samd51/flash-const.patch b/atmel-samd/asf4/patches/samd51/flash-const.patch
new file mode 100644
index 000000000..087581ff0
--- /dev/null
+++ b/atmel-samd/asf4/patches/samd51/flash-const.patch
@@ -0,0 +1,63 @@
+--- a/hal/include/hal_flash.h
++++ b/hal/include/hal_flash.h
+@@ -132,7 +132,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
+  *  \param[in]  length    Number of bytes to append
+  *  \return Append status.
+  */
+-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length);
++int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
+
+ /** \brief Reads a number of bytes to a page in the internal Flash
+  *
+--- a/hal/include/hpl_flash.h
++++ b/hal/include/hpl_flash.h
+@@ -125,7 +125,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
+  *                           write is stored
+  * \param[in]  length        Number of bytes to write
+  */
+-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
++void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
+
+ /**
+  * \brief Appends a number of bytes in the internal Flash.
+@@ -135,7 +135,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
+  * \param[in]  buffer        Pointer to buffer with data to write to flash
+  * \param[in]  length        Number of bytes to write
+  */
+-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
++void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
+
+ /** \brief Execute lock in the internal flash
+  *  \param[in] device         The pointer to FLASH device instance
+
+--- a/hal/src/hal_flash.c
++++ b/hal/src/hal_flash.c
+@@ -135,7 +135,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
+ /**
+  * \brief Appends a number of bytes to a page in the internal Flash
+  */
+-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length)
++int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
+ {
+        ASSERT(flash && buffer && length);
+
+--- a/hpl/nvmctrl/hpl_nvmctrl.c
++++ b/hpl/nvmctrl/hpl_nvmctrl.c
+@@ -167,7 +167,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
+ /**
+  * \brief Writes a number of bytes to a page in the internal Flash.
+  */
+-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
++void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
+ {
+        uint8_t  tmp_buffer[NVMCTRL_BLOCK_PAGES][NVMCTRL_PAGE_SIZE];
+        uint32_t block_start_addr, block_end_addr;
+@@ -212,7 +212,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
+ /**
+  * \brief Appends a number of bytes in the internal Flash.
+  */
+-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
++void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
+ {
+        uint32_t page_start_addr = dst_addr & ~(NVMCTRL_PAGE_SIZE - 1);
+        uint32_t size;
diff --git a/atmel-samd/asf4/samd21/hal/include/hal_flash.h b/atmel-samd/asf4/samd21/hal/include/hal_flash.h
index 2e6286389..ffba519de 100644
--- a/atmel-samd/asf4/samd21/hal/include/hal_flash.h
+++ b/atmel-samd/asf4/samd21/hal/include/hal_flash.h
@@ -132,7 +132,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
  *  \param[in]  length    Number of bytes to append
  *  \return Append status.
  */
-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length);
+int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
 
 /** \brief Reads a number of bytes to a page in the internal Flash
  *
diff --git a/atmel-samd/asf4/samd21/hal/include/hpl_flash.h b/atmel-samd/asf4/samd21/hal/include/hpl_flash.h
index 774bb5e0b..6a59f757c 100644
--- a/atmel-samd/asf4/samd21/hal/include/hpl_flash.h
+++ b/atmel-samd/asf4/samd21/hal/include/hpl_flash.h
@@ -125,7 +125,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
  *                           write is stored
  * \param[in]  length        Number of bytes to write
  */
-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
+void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
 
 /**
  * \brief Appends a number of bytes in the internal Flash.
@@ -135,7 +135,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
  * \param[in]  buffer        Pointer to buffer with data to write to flash
  * \param[in]  length        Number of bytes to write
  */
-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
+void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
 
 /** \brief Execute lock in the internal flash
  *  \param[in] device         The pointer to FLASH device instance
diff --git a/atmel-samd/asf4/samd21/hal/src/hal_flash.c b/atmel-samd/asf4/samd21/hal/src/hal_flash.c
index f3cc4bbfe..165d46d89 100644
--- a/atmel-samd/asf4/samd21/hal/src/hal_flash.c
+++ b/atmel-samd/asf4/samd21/hal/src/hal_flash.c
@@ -135,7 +135,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
 /**
  * \brief Appends a number of bytes to a page in the internal Flash
  */
-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length)
+int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
 {
 	ASSERT(flash && buffer && length);
 
@@ -304,7 +304,10 @@ static int32_t flash_is_address_aligned(struct flash_descriptor *flash, const ui
  */
 static void flash_ready(struct _flash_device *device)
 {
+	#pragma GCC diagnostic push
+	#pragma GCC diagnostic ignored "-Wcast-align"
 	struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
+	#pragma GCC diagnostic pop
 	if (descr->callbacks.cb_ready) {
 		descr->callbacks.cb_ready(descr);
 	}
@@ -317,7 +320,10 @@ static void flash_ready(struct _flash_device *device)
  */
 static void flash_error(struct _flash_device *device)
 {
+	#pragma GCC diagnostic push
+	#pragma GCC diagnostic ignored "-Wcast-align"
 	struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
+	#pragma GCC diagnostic pop
 	if (descr->callbacks.cb_error) {
 		descr->callbacks.cb_error(descr);
 	}
diff --git a/atmel-samd/asf4/samd21/hpl/nvmctrl/hpl_nvmctrl.c b/atmel-samd/asf4/samd21/hpl/nvmctrl/hpl_nvmctrl.c
index 2c9131a1a..3e751e3d5 100644
--- a/atmel-samd/asf4/samd21/hpl/nvmctrl/hpl_nvmctrl.c
+++ b/atmel-samd/asf4/samd21/hpl/nvmctrl/hpl_nvmctrl.c
@@ -175,7 +175,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
 /**
  * \brief Writes a number of bytes to a page in the internal Flash.
  */
-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
+void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
 {
 	uint8_t  tmp_buffer[NVMCTRL_ROW_PAGES][NVMCTRL_PAGE_SIZE];
 	uint32_t row_start_addr, row_end_addr;
@@ -219,7 +219,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
 /**
  * \brief Appends a number of bytes in the internal Flash.
  */
-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
+void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
 {
 	uint32_t page_start_addr = dst_addr & ~(NVMCTRL_PAGE_SIZE - 1);
 	uint32_t size;
diff --git a/atmel-samd/asf4/samd51/CMSIS/Include/core_cm4.h b/atmel-samd/asf4/samd51/CMSIS/Include/core_cm4.h
index bb6be1305..2ebde319d 100644
--- a/atmel-samd/asf4/samd51/CMSIS/Include/core_cm4.h
+++ b/atmel-samd/asf4/samd51/CMSIS/Include/core_cm4.h
@@ -1493,8 +1493,12 @@ __STATIC_INLINE uint32_t NVIC_GetPriorityGrouping(void)
  */
 __STATIC_INLINE void NVIC_EnableIRQ(IRQn_Type IRQn)
 {
+
+  #pragma GCC diagnostic push
+  #pragma GCC diagnostic ignored "-Warray-bounds"
 /*  NVIC->ISER[((uint32_t)(IRQn) >> 5)] = (1 << ((uint32_t)(IRQn) & 0x1F));  enable interrupt */
   NVIC->ISER[(uint32_t)((int32_t)IRQn) >> 5] = (uint32_t)(1 << ((uint32_t)((int32_t)IRQn) & (uint32_t)0x1F)); /* enable interrupt */
+  #pragma GCC diagnostic pop
 }
 
 
diff --git a/atmel-samd/asf4/samd51/hal/include/hal_flash.h b/atmel-samd/asf4/samd51/hal/include/hal_flash.h
index 2e6286389..ffba519de 100644
--- a/atmel-samd/asf4/samd51/hal/include/hal_flash.h
+++ b/atmel-samd/asf4/samd51/hal/include/hal_flash.h
@@ -132,7 +132,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
  *  \param[in]  length    Number of bytes to append
  *  \return Append status.
  */
-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length);
+int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
 
 /** \brief Reads a number of bytes to a page in the internal Flash
  *
diff --git a/atmel-samd/asf4/samd51/hal/include/hpl_flash.h b/atmel-samd/asf4/samd51/hal/include/hpl_flash.h
index 774bb5e0b..6a59f757c 100644
--- a/atmel-samd/asf4/samd51/hal/include/hpl_flash.h
+++ b/atmel-samd/asf4/samd51/hal/include/hpl_flash.h
@@ -125,7 +125,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
  *                           write is stored
  * \param[in]  length        Number of bytes to write
  */
-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
+void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
 
 /**
  * \brief Appends a number of bytes in the internal Flash.
@@ -135,7 +135,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
  * \param[in]  buffer        Pointer to buffer with data to write to flash
  * \param[in]  length        Number of bytes to write
  */
-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length);
+void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length);
 
 /** \brief Execute lock in the internal flash
  *  \param[in] device         The pointer to FLASH device instance
diff --git a/atmel-samd/asf4/samd51/hal/src/hal_flash.c b/atmel-samd/asf4/samd51/hal/src/hal_flash.c
index f3cc4bbfe..165d46d89 100644
--- a/atmel-samd/asf4/samd51/hal/src/hal_flash.c
+++ b/atmel-samd/asf4/samd51/hal/src/hal_flash.c
@@ -135,7 +135,7 @@ int32_t flash_write(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *
 /**
  * \brief Appends a number of bytes to a page in the internal Flash
  */
-int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, uint8_t *buffer, uint32_t length)
+int32_t flash_append(struct flash_descriptor *flash, uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
 {
 	ASSERT(flash && buffer && length);
 
@@ -304,7 +304,10 @@ static int32_t flash_is_address_aligned(struct flash_descriptor *flash, const ui
  */
 static void flash_ready(struct _flash_device *device)
 {
+	#pragma GCC diagnostic push
+	#pragma GCC diagnostic ignored "-Wcast-align"
 	struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
+	#pragma GCC diagnostic pop
 	if (descr->callbacks.cb_ready) {
 		descr->callbacks.cb_ready(descr);
 	}
@@ -317,7 +320,10 @@ static void flash_ready(struct _flash_device *device)
  */
 static void flash_error(struct _flash_device *device)
 {
+	#pragma GCC diagnostic push
+	#pragma GCC diagnostic ignored "-Wcast-align"
 	struct flash_descriptor *const descr = CONTAINER_OF(device, struct flash_descriptor, dev);
+	#pragma GCC diagnostic pop
 	if (descr->callbacks.cb_error) {
 		descr->callbacks.cb_error(descr);
 	}
diff --git a/atmel-samd/asf4/samd51/hpl/nvmctrl/hpl_nvmctrl.c b/atmel-samd/asf4/samd51/hpl/nvmctrl/hpl_nvmctrl.c
index 2f7f01d5e..3d9df6db4 100644
--- a/atmel-samd/asf4/samd51/hpl/nvmctrl/hpl_nvmctrl.c
+++ b/atmel-samd/asf4/samd51/hpl/nvmctrl/hpl_nvmctrl.c
@@ -167,7 +167,7 @@ void _flash_read(struct _flash_device *const device, const uint32_t src_addr, ui
 /**
  * \brief Writes a number of bytes to a page in the internal Flash.
  */
-void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
+void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
 {
 	uint8_t  tmp_buffer[NVMCTRL_BLOCK_PAGES][NVMCTRL_PAGE_SIZE];
 	uint32_t block_start_addr, block_end_addr;
@@ -212,7 +212,7 @@ void _flash_write(struct _flash_device *const device, const uint32_t dst_addr, u
 /**
  * \brief Appends a number of bytes in the internal Flash.
  */
-void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, uint8_t *buffer, uint32_t length)
+void _flash_append(struct _flash_device *const device, const uint32_t dst_addr, const uint8_t *buffer, uint32_t length)
 {
 	uint32_t page_start_addr = dst_addr & ~(NVMCTRL_PAGE_SIZE - 1);
 	uint32_t size;
@@ -386,7 +386,10 @@ static void _flash_erase_block(void *const hw, const uint32_t dst_addr)
  */
 static void _flash_program(void *const hw, const uint32_t dst_addr, const uint8_t *buffer, const uint16_t size)
 {
+	#pragma GCC diagnostic push
+	#pragma GCC diagnostic ignored "-Wcast-align"
 	uint32_t *ptr_read    = (uint32_t *)buffer;
+	#pragma GCC diagnostic pop
 	uint32_t  nvm_address = dst_addr / 4;
 	uint16_t  i;
 
diff --git a/atmel-samd/asf4_conf/samd21/hpl_nvmctrl_config.h b/atmel-samd/asf4_conf/samd21/hpl_nvmctrl_config.h
new file mode 100644
index 000000000..88d6bb93f
--- /dev/null
+++ b/atmel-samd/asf4_conf/samd21/hpl_nvmctrl_config.h
@@ -0,0 +1,38 @@
+/* Auto-generated config file hpl_nvmctrl_config.h */
+#ifndef HPL_NVMCTRL_CONFIG_H
+#define HPL_NVMCTRL_CONFIG_H
+
+// <<< Use Configuration Wizard in Context Menu >>>
+
+// <h> Basic Settings
+
+// <o> Read Mode Selection
+// <0x00=> No Miss Penalty
+// <0x01=> Low Power
+// <0x02=> Deterministic
+// <id> nvm_arch_read_mode
+#ifndef CONF_NVM_READ_MODE
+#define CONF_NVM_READ_MODE 0
+#endif
+
+// <o> Power Reduction Mode During Sleep
+// <0x00=> Wake On Access
+// <0x01=> Wake Up Instant
+// <0x03=> Disabled
+// <id> nvm_arch_sleepprm
+#ifndef CONF_NVM_SLEEPPRM
+#define CONF_NVM_SLEEPPRM 0
+#endif
+
+// <q> Cache Disable
+// <i> Indicate whether cache is disable or not
+// <id> nvm_arch_cache
+#ifndef CONF_NVM_CACHE
+#define CONF_NVM_CACHE 0
+#endif
+
+// </h>
+
+// <<< end of configuration section >>>
+
+#endif // HPL_NVMCTRL_CONFIG_H
diff --git a/atmel-samd/asf4_conf/samd51/hpl_nvmctrl_config.h b/atmel-samd/asf4_conf/samd51/hpl_nvmctrl_config.h
new file mode 100644
index 000000000..daaba85d4
--- /dev/null
+++ b/atmel-samd/asf4_conf/samd51/hpl_nvmctrl_config.h
@@ -0,0 +1,36 @@
+/* Auto-generated config file hpl_nvmctrl_config.h */
+#ifndef HPL_NVMCTRL_CONFIG_H
+#define HPL_NVMCTRL_CONFIG_H
+
+// <<< Use Configuration Wizard in Context Menu >>>
+
+// <h> Basic Settings
+
+// <o> Power Reduction Mode During Sleep
+// <0x00=> Wake On Access
+// <0x01=> Wake Up Instant
+// <0x03=> Disabled
+// <id> nvm_arch_sleepprm
+#ifndef CONF_NVM_SLEEPPRM
+#define CONF_NVM_SLEEPPRM 0
+#endif
+
+// <q> AHB0 Cache Disable
+// <i> Indicate whether AHB0 cache is disable or not
+// <id> nvm_arch_cache0
+#ifndef CONF_NVM_CACHE0
+#define CONF_NVM_CACHE0 0
+#endif
+
+// <q> AHB1 Cache Disable
+// <i> Indicate whether AHB1 cache is disable or not
+// <id> nvm_arch_cache1
+#ifndef CONF_NVM_CACHE1
+#define CONF_NVM_CACHE1 0
+#endif
+
+// </h>
+
+// <<< end of configuration section >>>
+
+#endif // HPL_NVMCTRL_CONFIG_H
diff --git a/atmel-samd/asf4_conf/samd51/hpl_trng_config.h b/atmel-samd/asf4_conf/samd51/hpl_trng_config.h
new file mode 100644
index 000000000..ba9014989
--- /dev/null
+++ b/atmel-samd/asf4_conf/samd51/hpl_trng_config.h
@@ -0,0 +1,27 @@
+/* Auto-generated config file hpl_trng_config.h */
+#ifndef HPL_TRNG_CONFIG_H
+#define HPL_TRNG_CONFIG_H
+
+// <<< Use Configuration Wizard in Context Menu >>>
+
+// <h> Advanced configurations
+
+// <q> Run In Standby
+// <i> Indicates whether the TRNG works in standby mode
+// <id> trng_runstdby
+#ifndef CONF_TRNG_RUNSTDBY
+#define CONF_TRNG_RUNSTDBY 0
+#endif
+
+// <q> Data Ready Event Output Enable
+// <i> Indicates whether the TRNG generates event on Data Ready
+// <id> trng_datardyeo
+#ifndef CONF_TRNG_DATARDYEO
+#define CONF_TRNG_DATARDYEO 0
+#endif
+
+// </h>
+
+// <<< end of configuration section >>>
+
+#endif // HPL_TRNG_CONFIG_H
diff --git a/atmel-samd/boards/circuitplayground_express/mpconfigboard.h b/atmel-samd/boards/circuitplayground_express/mpconfigboard.h
index a12ac51a0..e1056ae94 100644
--- a/atmel-samd/boards/circuitplayground_express/mpconfigboard.h
+++ b/atmel-samd/boards/circuitplayground_express/mpconfigboard.h
@@ -24,7 +24,8 @@
 
 #define SPEAKER_ENABLE_PIN    (&pin_PA30)
 
-#include "spi_flash.h"
+#include "internal_flash.h"
+//#include "spi_flash.h"
 
 // If you change this, then make sure to update the linker scripts as well to
 // make sure you don't overwrite code.
diff --git a/atmel-samd/boards/circuitplayground_express/mpconfigboard.mk b/atmel-samd/boards/circuitplayground_express/mpconfigboard.mk
index 0a93ccddc..538a737db 100644
--- a/atmel-samd/boards/circuitplayground_express/mpconfigboard.mk
+++ b/atmel-samd/boards/circuitplayground_express/mpconfigboard.mk
@@ -1,8 +1,9 @@
-LD_FILE = boards/samd21x18-bootloader-external-flash-crystalless.ld
+LD_FILE = boards/samd21x18-bootloader-crystalless.ld
 USB_VID = 0x239A
 USB_PID = 0x8019
 
-FLASH_IMPL = spi_flash.c
+#FLASH_IMPL = spi_flash.c
+FLASH_IMPL = internal_flash.c
 
 CHIP_VARIANT = SAMD21G18A
 CHIP_FAMILY = samd21
diff --git a/atmel-samd/boards/feather_m0_express/mpconfigboard.h b/atmel-samd/boards/feather_m0_express/mpconfigboard.h
index 9f9c25a7d..39706e260 100644
--- a/atmel-samd/boards/feather_m0_express/mpconfigboard.h
+++ b/atmel-samd/boards/feather_m0_express/mpconfigboard.h
@@ -20,7 +20,8 @@
 #define MICROPY_PORT_B        ( 0 )
 #define MICROPY_PORT_C        ( 0 )
 
-#include "spi_flash.h"
+#include "internal_flash.h"
+//#include "spi_flash.h"
 
 // If you change this, then make sure to update the linker scripts as well to
 // make sure you don't overwrite code.
diff --git a/atmel-samd/boards/feather_m0_express/mpconfigboard.mk b/atmel-samd/boards/feather_m0_express/mpconfigboard.mk
index 5840a5cf9..cdcfd4108 100644
--- a/atmel-samd/boards/feather_m0_express/mpconfigboard.mk
+++ b/atmel-samd/boards/feather_m0_express/mpconfigboard.mk
@@ -1,8 +1,9 @@
-LD_FILE = boards/samd21x18-bootloader-external-flash.ld
+LD_FILE = boards/samd21x18-bootloader.ld
 USB_VID = 0x239A
 USB_PID = 0x801b
 
-FLASH_IMPL = spi_flash.c
+#FLASH_IMPL = spi_flash.c
+FLASH_IMPL = internal_flash.c
 
 CHIP_VARIANT = SAMD21G18A
 CHIP_FAMILY = samd21
diff --git a/atmel-samd/boards/metro_m0_express/mpconfigboard.h b/atmel-samd/boards/metro_m0_express/mpconfigboard.h
index 291967c88..de3cf29da 100644
--- a/atmel-samd/boards/metro_m0_express/mpconfigboard.h
+++ b/atmel-samd/boards/metro_m0_express/mpconfigboard.h
@@ -24,7 +24,8 @@
 #define MICROPY_PORT_B        (PORT_PB03 | PORT_PB22 | PORT_PB23)
 #define MICROPY_PORT_C        (0)
 
-#include "spi_flash.h"
+#include "internal_flash.h"
+//#include "spi_flash.h"
 
 // If you change this, then make sure to update the linker scripts as well to
 // make sure you don't overwrite code.
diff --git a/atmel-samd/boards/metro_m0_express/mpconfigboard.mk b/atmel-samd/boards/metro_m0_express/mpconfigboard.mk
index 763738748..82d673f02 100644
--- a/atmel-samd/boards/metro_m0_express/mpconfigboard.mk
+++ b/atmel-samd/boards/metro_m0_express/mpconfigboard.mk
@@ -1,8 +1,9 @@
-LD_FILE = boards/samd21x18-bootloader-external-flash.ld
+LD_FILE = boards/samd21x18-bootloader.ld
 USB_VID = 0x239A
 USB_PID = 0x8014
 
-FLASH_IMPL = spi_flash.c
+#FLASH_IMPL = spi_flash.c
+FLASH_IMPL = internal_flash.c
 
 CHIP_VARIANT = SAMD21G18A
 CHIP_FAMILY = samd21
diff --git a/atmel-samd/boards/metro_m4_express/mpconfigboard.mk b/atmel-samd/boards/metro_m4_express/mpconfigboard.mk
index fd299c7f9..a21be5138 100644
--- a/atmel-samd/boards/metro_m4_express/mpconfigboard.mk
+++ b/atmel-samd/boards/metro_m4_express/mpconfigboard.mk
@@ -1,8 +1,9 @@
-LD_FILE = boards/samd51x20-bootloader-external-flash.ld
+LD_FILE = boards/samd51x20.ld
 USB_VID = 0x239A
 USB_PID = 0x8015
 
-FLASH_IMPL = spi_flash.c
+#FLASH_IMPL = spi_flash.c
+FLASH_IMPL = internal_flash.c
 
 CHIP_VARIANT = SAMD51J20A
 CHIP_FAMILY = samd51
diff --git a/atmel-samd/boards/samd51x18-bootloader-external-flash.ld b/atmel-samd/boards/samd51x18-bootloader-external-flash.ld
index b009de640..f4ad37c20 100644
--- a/atmel-samd/boards/samd51x18-bootloader-external-flash.ld
+++ b/atmel-samd/boards/samd51x18-bootloader-external-flash.ld
@@ -1,5 +1,5 @@
 /*
-    GNU linker script for SAMD21
+    GNU linker script for SAMD51
 */
 
 /* Specify the memory areas */
diff --git a/atmel-samd/boards/samd51x19-bootloader-external-flash.ld b/atmel-samd/boards/samd51x19-bootloader-external-flash.ld
index bea575797..4e4e8b002 100644
--- a/atmel-samd/boards/samd51x19-bootloader-external-flash.ld
+++ b/atmel-samd/boards/samd51x19-bootloader-external-flash.ld
@@ -1,5 +1,5 @@
 /*
-    GNU linker script for SAMD21
+    GNU linker script for SAMD51
 */
 
 /* Specify the memory areas */
diff --git a/atmel-samd/boards/samd51x20-bootloader-external-flash.ld b/atmel-samd/boards/samd51x20-bootloader-external-flash.ld
index e9c67de97..57bf299fb 100644
--- a/atmel-samd/boards/samd51x20-bootloader-external-flash.ld
+++ b/atmel-samd/boards/samd51x20-bootloader-external-flash.ld
@@ -1,5 +1,5 @@
 /*
-    GNU linker script for SAMD21
+    GNU linker script for SAMD51
 */
 
 /* Specify the memory areas */
diff --git a/atmel-samd/boards/samd51x20-external-flash.ld b/atmel-samd/boards/samd51x20-external-flash.ld
index 701e24762..b0a118507 100644
--- a/atmel-samd/boards/samd51x20-external-flash.ld
+++ b/atmel-samd/boards/samd51x20-external-flash.ld
@@ -1,5 +1,5 @@
 /*
-    GNU linker script for SAMD21
+    GNU linker script for SAMD51
 */
 
 /* Specify the memory areas */
diff --git a/atmel-samd/boards/samd51x20.ld b/atmel-samd/boards/samd51x20.ld
new file mode 100644
index 000000000..4d2da5d13
--- /dev/null
+++ b/atmel-samd/boards/samd51x20.ld
@@ -0,0 +1,81 @@
+/*
+    GNU linker script for SAMD51
+*/
+
+/* Specify the memory areas */
+MEMORY
+{
+    FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 0x00100000 - 0x80000 /* 1024 KiB mius 512KiB for the internal file system. */
+    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 0x00040000 /* 256 KiB */
+}
+
+/* top end of the stack */
+_estack = ORIGIN(RAM) + LENGTH(RAM);
+
+/* define output sections */
+SECTIONS
+{
+    /* The program code and other data goes into FLASH */
+    .text :
+    {
+        . = ALIGN(4);
+        _sfixed = .;
+        KEEP(*(.vectors)) /* isr vector table */
+        *(.text)           /* .text sections (code) */
+        *(.text*)          /* .text* sections (code) */
+        *(.rodata)         /* .rodata sections (constants, strings, etc.) */
+        *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
+
+        . = ALIGN(4);
+        _etext = .;        /* define a global symbol at end of code */
+    } >FLASH
+
+    .ARM.exidx :
+    {
+        *(.ARM.exidx*)
+        *(.gnu.linkonce.armexidx.*)
+        _sidata = .;  /* This is used by the startup in order to initialize the .data section */
+    } > FLASH
+
+    /* This is the initialized data section
+    The program executes knowing that the data is in the RAM
+    but the loader puts the initial values in the FLASH (inidata).
+    It is one task of the startup to copy the initial values from FLASH to RAM. */
+    .data : AT ( _sidata )
+    {
+        . = ALIGN(4);
+        _srelocate = .;        /* create a global symbol at data start; used by startup code in order to initialise the .data section in RAM */
+        *(.ramfunc)
+        *(.ramfunc*)
+        *(.data)           /* .data sections */
+        *(.data*)          /* .data* sections */
+
+        . = ALIGN(4);
+        _erelocate = .;        /* define a global symbol at data end; used by startup code in order to initialise the .data section in RAM */
+    } >RAM
+
+    /* Uninitialized data section */
+    .bss :
+    {
+        . = ALIGN(4);
+        _sbss = .;
+        _szero = .;         /* define a global symbol at bss start; used by startup code */
+        *(.bss)
+        *(.bss*)
+        *(COMMON)
+
+        . = ALIGN(4);
+        _ezero = .;         /* define a global symbol at bss end; used by startup code */
+        _ebss = .;
+    } >RAM
+
+    /* this just checks there is enough RAM for a minimal stack */
+    .stack :
+    {
+        . = ALIGN(4);
+        . = . + 0x800; /* Reserve a minimum of 2K for the stack. */
+        . = ALIGN(4);
+    } >RAM
+
+    .ARM.attributes 0 : { *(.ARM.attributes) }
+}
diff --git a/atmel-samd/common-hal/os/__init__.c b/atmel-samd/common-hal/os/__init__.c
index 2df4e40ff..eeba29dfa 100644
--- a/atmel-samd/common-hal/os/__init__.c
+++ b/atmel-samd/common-hal/os/__init__.c
@@ -30,12 +30,22 @@
 #include "py/objtuple.h"
 #include "py/qstr.h"
 
+#ifdef SAMD51
+#include "hal/include/hal_rand_sync.h"
+#endif
+
 STATIC const qstr os_uname_info_fields[] = {
     MP_QSTR_sysname, MP_QSTR_nodename,
     MP_QSTR_release, MP_QSTR_version, MP_QSTR_machine
 };
+#ifdef SAMD21
 STATIC const MP_DEFINE_STR_OBJ(os_uname_info_sysname_obj, "samd21");
 STATIC const MP_DEFINE_STR_OBJ(os_uname_info_nodename_obj, "samd21");
+#endif
+#ifdef SAMD51
+STATIC const MP_DEFINE_STR_OBJ(os_uname_info_sysname_obj, "samd51");
+STATIC const MP_DEFINE_STR_OBJ(os_uname_info_nodename_obj, "samd51");
+#endif
 STATIC const MP_DEFINE_STR_OBJ(os_uname_info_release_obj, MICROPY_VERSION_STRING);
 STATIC const MP_DEFINE_STR_OBJ(os_uname_info_version_obj, MICROPY_GIT_TAG " on " MICROPY_BUILD_DATE);
 STATIC const MP_DEFINE_STR_OBJ(os_uname_info_machine_obj, MICROPY_HW_BOARD_NAME " with " MICROPY_HW_MCU_NAME);
@@ -57,5 +67,19 @@ mp_obj_t common_hal_os_uname(void) {
 }
 
 bool common_hal_os_urandom(uint8_t* buffer, uint32_t length) {
+    #ifdef SAMD51
+    hri_mclk_set_APBCMASK_TRNG_bit(MCLK);
+    struct rand_sync_desc random;
+    rand_sync_init(&random, TRNG);
+    rand_sync_enable(&random);
+
+    rand_sync_read_buf8(&random, buffer, length);
+
+    rand_sync_disable(&random);
+    rand_sync_deinit(&random);
+    hri_mclk_clear_APBCMASK_TRNG_bit(MCLK);
+    return true;
+    #else
     return false;
+    #endif
 }
diff --git a/atmel-samd/internal_flash.c b/atmel-samd/internal_flash.c
index 4447f15d6..53a0a0c24 100644
--- a/atmel-samd/internal_flash.c
+++ b/atmel-samd/internal_flash.c
@@ -35,10 +35,14 @@
 #include "py/runtime.h"
 #include "lib/oofatfs/ff.h"
 
-#include "asf/sam0/drivers/nvm/nvm.h"
-#include "asf/sam0/drivers/port/port.h"
+#ifdef SAMD21
+#include "hpl/pm/hpl_pm_base.h"
+#endif
+#include "hal/include/hal_flash.h"
 
-#include "rgb_led_status.h"
+#include "supervisor/shared/rgb_led_status.h"
+
+static struct flash_descriptor internal_flash_desc;
 
 void internal_flash_init(void) {
     // Activity LED for flash writes.
@@ -50,6 +54,14 @@ void internal_flash_init(void) {
         port_pin_set_config(MICROPY_HW_LED_MSC, &pin_conf);
         port_pin_set_output_level(MICROPY_HW_LED_MSC, false);
     #endif
+
+    #ifdef SAMD51
+    hri_mclk_set_AHBMASK_NVMCTRL_bit(MCLK);
+    #endif
+    #ifdef SAMD21
+    _pm_enable_bus_clock(PM_BUS_APBB, NVMCTRL);
+    #endif
+    flash_init(&internal_flash_desc, NVMCTRL);
 }
 
 uint32_t internal_flash_get_block_size(void) {
@@ -138,18 +150,8 @@ bool internal_flash_read_block(uint8_t *dest, uint32_t block) {
             // bad block number
             return false;
         }
-        enum status_code error_code;
-        // A block is made up of multiple pages. Read each page
-        // sequentially.
-        for (int i = 0; i < FILESYSTEM_BLOCK_SIZE / NVMCTRL_PAGE_SIZE; i++) {
-          do
-          {
-              error_code = nvm_read_buffer(src + i * NVMCTRL_PAGE_SIZE,
-                                   dest + i * NVMCTRL_PAGE_SIZE,
-                                   NVMCTRL_PAGE_SIZE);
-          } while (error_code == STATUS_BUSY);
-        }
-        return true;
+        int32_t error_code = flash_read(&internal_flash_desc, src, dest, FILESYSTEM_BLOCK_SIZE);
+        return error_code == ERR_NONE;
     }
 }
 
@@ -169,36 +171,21 @@ bool internal_flash_write_block(const uint8_t *src, uint32_t block) {
             // bad block number
             return false;
         }
-        enum status_code error_code;
+        int32_t error_code;
         // A block is formed by two rows of flash. We must erase each row
         // before we write back to it.
-        do
-        {
-            error_code = nvm_erase_row(dest);
-        } while (error_code == STATUS_BUSY);
-        if (error_code != STATUS_OK) {
-            return false;
-        }
-        do
-        {
-            error_code = nvm_erase_row(dest + NVMCTRL_ROW_SIZE);
-        } while (error_code == STATUS_BUSY);
-        if (error_code != STATUS_OK) {
+        error_code = flash_erase(&internal_flash_desc,
+                                 dest,
+                                 FILESYSTEM_BLOCK_SIZE / flash_get_page_size(&internal_flash_desc));
+        if (error_code != ERR_NONE) {
             return false;
         }
 
         // A block is made up of multiple pages. Write each page
         // sequentially.
-        for (int i = 0; i < FILESYSTEM_BLOCK_SIZE / NVMCTRL_PAGE_SIZE; i++) {
-          do
-          {
-              error_code = nvm_write_buffer(dest + i * NVMCTRL_PAGE_SIZE,
-                                    src + i * NVMCTRL_PAGE_SIZE,
-                                    NVMCTRL_PAGE_SIZE);
-          } while (error_code == STATUS_BUSY);
-          if (error_code != STATUS_OK) {
-              return false;
-          }
+        error_code = flash_append(&internal_flash_desc, dest, src, FILESYSTEM_BLOCK_SIZE);
+        if (error_code != ERR_NONE) {
+            return false;
         }
         clear_temp_status();
         #ifdef MICROPY_HW_LED_MSC
diff --git a/atmel-samd/internal_flash.h b/atmel-samd/internal_flash.h
index 3de831f63..88c105386 100644
--- a/atmel-samd/internal_flash.h
+++ b/atmel-samd/internal_flash.h
@@ -30,11 +30,19 @@
 
 #include "mpconfigport.h"
 
+#include "sam.h"
+
 #define FLASH_ROOT_POINTERS
 
+#ifdef SAMD51
+#define TOTAL_INTERNAL_FLASH_SIZE (FLASH_SIZE / 2)
+#endif
+
+#ifdef SAMD21
 #define TOTAL_INTERNAL_FLASH_SIZE 0x010000
+#endif
 
-#define INTERNAL_FLASH_MEM_SEG1_START_ADDR (0x00040000 - TOTAL_INTERNAL_FLASH_SIZE - CIRCUITPY_INTERNAL_NVM_SIZE)
+#define INTERNAL_FLASH_MEM_SEG1_START_ADDR (FLASH_SIZE - TOTAL_INTERNAL_FLASH_SIZE - CIRCUITPY_INTERNAL_NVM_SIZE)
 #define INTERNAL_FLASH_PART1_START_BLOCK (0x1)
 #define INTERNAL_FLASH_PART1_NUM_BLOCKS (TOTAL_INTERNAL_FLASH_SIZE / FILESYSTEM_BLOCK_SIZE)
 
diff --git a/atmel-samd/mpconfigport.h b/atmel-samd/mpconfigport.h
index 8881803e4..3bdf3bfbd 100644
--- a/atmel-samd/mpconfigport.h
+++ b/atmel-samd/mpconfigport.h
@@ -3,10 +3,6 @@
 #ifndef __INCLUDED_MPCONFIGPORT_H
 #define __INCLUDED_MPCONFIGPORT_H
 
-#define PORT_HEAP_SIZE (16384 + 4096)
-
-#define MICROPY_PY_SYS_PLATFORM                     "Atmel SAMD21"
-
 #define MICROPY_OBJ_REPR            (MICROPY_OBJ_REPR_C)
 
 // options to control how MicroPython is built
@@ -138,10 +134,14 @@ typedef long mp_off_t;
 
 #ifdef SAMD21
 #define CIRCUITPY_MCU_FAMILY samd21
+#define MICROPY_PY_SYS_PLATFORM                     "Atmel SAMD21"
+#define PORT_HEAP_SIZE (16384 + 4096)
 #endif
 
 #ifdef SAMD51
 #define CIRCUITPY_MCU_FAMILY samd51
+#define MICROPY_PY_SYS_PLATFORM                     "MicroChip SAMD51"
+#define PORT_HEAP_SIZE (0x20000) // 128KiB
 #endif
 
 // extra built in modules to add to the list of known ones
@@ -205,8 +205,6 @@ extern const struct _mp_obj_module_t usb_hid_module;
 //    { MP_OBJ_NEW_QSTR(MP_QSTR_busio), (mp_obj_t)&busio_module },
 //    { MP_OBJ_NEW_QSTR(MP_QSTR_neopixel_write),(mp_obj_t)&neopixel_write_module },
 //    { MP_OBJ_NEW_QSTR(MP_QSTR_usb_hid),(mp_obj_t)&usb_hid_module },
-//    { MP_OBJ_NEW_QSTR(MP_QSTR_os), (mp_obj_t)&os_module },
-//    { MP_OBJ_NEW_QSTR(MP_QSTR_random), (mp_obj_t)&random_module },
 //    { MP_OBJ_NEW_QSTR(MP_QSTR_storage), (mp_obj_t)&storage_module },
 //    { MP_OBJ_NEW_QSTR(MP_QSTR_samd),(mp_obj_t)&samd_module },
 
@@ -215,6 +213,8 @@ extern const struct _mp_obj_module_t usb_hid_module;
     { MP_OBJ_NEW_QSTR(MP_QSTR_board), (mp_obj_t)&board_module }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_digitalio), (mp_obj_t)&digitalio_module }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_microcontroller), (mp_obj_t)&microcontroller_module }, \
+    { MP_OBJ_NEW_QSTR(MP_QSTR_os), (mp_obj_t)&os_module }, \
+    { MP_OBJ_NEW_QSTR(MP_QSTR_random), (mp_obj_t)&random_module }, \
     { MP_OBJ_NEW_QSTR(MP_QSTR_time), (mp_obj_t)&time_module },
     EXTRA_BUILTIN_MODULES
 
diff --git a/atmel-samd/supervisor/filesystem.c b/atmel-samd/supervisor/filesystem.c
index a25a4b9e5..2dfb2bfd3 100644
--- a/atmel-samd/supervisor/filesystem.c
+++ b/atmel-samd/supervisor/filesystem.c
@@ -28,6 +28,10 @@
 #include "lib/oofatfs/ff.h"
 #include "lib/oofatfs/diskio.h"
 
+#include "py/mpstate.h"
+
+#include "flash_api.h"
+
 #ifdef EXPRESS_BOARD
 // #include "common-hal/touchio/TouchIn.h"
 #define INTERNAL_CIRCUITPY_CONFIG_START_ADDR (0x00040000 - 0x100 - CIRCUITPY_INTERNAL_NVM_SIZE)
@@ -41,38 +45,49 @@ mp_vfs_mount_t mp_vfs_mount_flash;
 // we don't make this function static because it needs a lot of stack and we
 // want it to be executed without using stack within main() function
 void filesystem_init(void) {
-    // // init the vfs object
-    // fs_user_mount_t *vfs_fat = &fs_user_mount_flash;
-    // vfs_fat->flags = 0;
-    // flash_init_vfs(vfs_fat);
-    //
-    // // try to mount the flash
-    // FRESULT res = f_mount(&vfs_fat->fatfs);
-    //
-    // if (res == FR_NO_FILESYSTEM) {
-    //     // no filesystem so create a fresh one
-    //
-    //     uint8_t working_buf[_MAX_SS];
-    //     res = f_mkfs(&vfs_fat->fatfs, FM_FAT, 0, working_buf, sizeof(working_buf));
-    //     // Flush the new file system to make sure its repaired immediately.
-    //     flash_flush();
-    //     if (res != FR_OK) {
-    //         return;
-    //     }
-    //
-    //     // set label
-    //     f_setlabel(&vfs_fat->fatfs, "CIRCUITPY");
-    // } else if (res != FR_OK) {
-    //     return;
-    // }
-    // mp_vfs_mount_t *vfs = &mp_vfs_mount_flash;
-    // vfs->str = "/";
-    // vfs->len = 1;
-    // vfs->obj = MP_OBJ_FROM_PTR(vfs_fat);
-    // vfs->next = NULL;
-    // MP_STATE_VM(vfs_mount_table) = vfs;
-    //
-    // // The current directory is used as the boot up directory.
-    // // It is set to the internal flash filesystem by default.
-    // MP_STATE_PORT(vfs_cur) = vfs;
+    // init the vfs object
+    fs_user_mount_t *vfs_fat = &fs_user_mount_flash;
+    vfs_fat->flags = 0;
+    flash_init_vfs(vfs_fat);
+
+    // try to mount the flash
+    FRESULT res = f_mount(&vfs_fat->fatfs);
+
+    if (res == FR_NO_FILESYSTEM) {
+        // no filesystem so create a fresh one
+        uint8_t working_buf[_MAX_SS];
+        res = f_mkfs(&vfs_fat->fatfs, FM_FAT, 0, working_buf, sizeof(working_buf));
+        // Flush the new file system to make sure its repaired immediately.
+        flash_flush();
+        if (res != FR_OK) {
+            return;
+        }
+
+        // set label
+        f_setlabel(&vfs_fat->fatfs, "CIRCUITPY");
+    } else if (res != FR_OK) {
+        return;
+    }
+    mp_vfs_mount_t *vfs = &mp_vfs_mount_flash;
+    vfs->str = "/";
+    vfs->len = 1;
+    vfs->obj = MP_OBJ_FROM_PTR(vfs_fat);
+    vfs->next = NULL;
+    MP_STATE_VM(vfs_mount_table) = vfs;
+
+    // The current directory is used as the boot up directory.
+    // It is set to the internal flash filesystem by default.
+    MP_STATE_PORT(vfs_cur) = vfs;
+}
+
+void filesystem_flush(void) {
+    flash_flush();
+}
+
+void filesystem_default_writeable(bool writeable) {
+    flash_set_usb_writeable(writeable);
+}
+
+bool filesystem_present(void) {
+    return true;
 }
diff --git a/atmel-samd/usb.c b/atmel-samd/usb.c
index 8d7870a2a..11a3d4eb9 100644
--- a/atmel-samd/usb.c
+++ b/atmel-samd/usb.c
@@ -123,6 +123,7 @@ static bool usb_device_cb_bulk_out(const uint8_t ep, const enum usb_xfer_code rc
     uint8_t buf[count];
     int32_t result = cdcdf_acm_read(buf, count);
     if (result != ERR_NONE) {
+        atomic_leave_critical(&flags);
         return true;
     }
 
diff --git a/supervisor/supervisor.mk b/supervisor/supervisor.mk
index f67439a97..c56557197 100644
--- a/supervisor/supervisor.mk
+++ b/supervisor/supervisor.mk
@@ -4,7 +4,7 @@ SRC_SUPERVISOR = \
 	supervisor/shared/autoreload.c \
 	supervisor/shared/rgb_led_status.c
 
-ifeq ($(wildcard supervisor/filesystem.c),)
+ifeq ($(wildcard atmel-samd/supervisor/filesystem.c),)
 	SRC_SUPERVISOR += supervisor/filesystem.c
 else
 	SRC_SUPERVISOR += supervisor/stub/filesystem.c