samv7: add support for user signature area in embedded flash

Embedded flash can have user signature area on SAMv7. This is a 512
bytes large page whose data are not erased by asserting ERASE pin or by
software ERASE command.

This commit adds arch to board interface for this area. It is possible
to perform read, write and erase operation. SAMV7_USER_SIGNATURE option
has to be set in the configuration.

Signed-off-by: Michal Lenc <michallenc@seznam.cz>

arch/arm/src/samv7/Kconfig

@@ -287,6 +287,10 @@ config SAMV7_HAVE_EBI
 	bool
 	default n
 
+config SAMV7_EEFC
+	bool
+	default n
+
 config SAMV7_EMAC
 	bool
 	default n
@@ -1786,6 +1790,7 @@ menuconfig SAMV7_PROGMEM
 	bool "FLASH program memory"
 	default n
 	select ARCH_HAVE_PROGMEM
+	select SAMV7_EEFC
 	---help---
 		Enable support FLASH interfaces as defined in include/nuttx/progmem.h
 
@@ -1804,6 +1809,16 @@ config SAMV7_PROGMEM_NSECTORS
 
 endif # SAMV7_PROGMEM
 
+config SAMV7_USER_SIGNATURE
+	bool "FLASH user signature"
+	default n
+	select SAMV7_EEFC
+	---help---
+		Each SAMv7 product contains a user signature area of 512 bytes in
+		embedded flash. It is possible to read, write and erase this area.
+		Data stored in this area are not erased by asserting ERASE pin or by
+		software ERASE command.
+
 menu "SDRAM Configuration"
 	depends on SAMV7_SDRAMC
 

arch/arm/src/samv7/Make.defs

@@ -137,8 +137,16 @@ ifeq ($(CONFIG_SAMV7_TRNG),y)
 CHIP_CSRCS += sam_trng.c
 endif
 
+ifeq ($(CONFIG_SAMV7_EEFC),y)
+CHIP_CSRCS += sam_eefc.c
+endif
+
 ifeq ($(CONFIG_SAMV7_PROGMEM),y)
-CHIP_CSRCS += sam_progmem.c sam_eefc.c
+CHIP_CSRCS += sam_progmem.c
+endif
+
+ifeq ($(CONFIG_SAMV7_USER_SIGNATURE),y)
+CHIP_CSRCS += sam_us.c
 endif
 
 ifeq ($(CONFIG_SAMV7_PWM),y)

arch/arm/src/samv7/sam_us.c

@@ -0,0 +1,172 @@
+/****************************************************************************
+ * arch/arm/src/samv7/sam_us.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <errno.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/mutex.h>
+#include <arch/samv7/chip.h>
+
+#include "hardware/sam_memorymap.h"
+
+#include "sam_eefc.h"
+#include "sam_us.h"
+
+#ifdef CONFIG_SAMV7_USER_SIGNATURE
+
+#define SAMV7_US_START      (SAM_INTFLASH_BASE)
+#define SAMV7_US_SIZE       (512)
+#define SAMV7_US_PAGE_WORDS (SAMV7_US_SIZE / sizeof(uint32_t))
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static uint32_t g_page_buffer[SAMV7_US_PAGE_WORDS];
+static mutex_t g_page_lock = NXMUTEX_INITIALIZER;
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sam_erase_user_signature
+ *
+ * Description:
+ *   Erases user signature page.
+ *
+ * Returned Value:
+ *   Zero on success, negated errno value on error.
+ *
+ ****************************************************************************/
+
+int sam_erase_user_signature(void)
+{
+  int ret;
+
+  ret = sam_eefc_command(EEFC_FCR_FCMD_EUS, 0);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  return 0;
+}
+
+/****************************************************************************
+ * Name: sam_write_user_signature
+ *
+ * Description:
+ *   Writes data to user signature page.
+ *
+ * Input Parameters:
+ *   buffer  - The buffer to be written to user signature.
+ *   buflen  - Number of bytes to be written.
+ *
+ * Returned Value:
+ *   Number of written bytes on success, negated errno on error.
+ *
+ ****************************************************************************/
+
+int sam_write_user_signature(void *buffer, size_t buflen)
+{
+  uint32_t *dest;
+  int ret;
+
+  if (buflen > SAMV7_US_SIZE)
+    {
+      return -ENOMEM;
+    }
+
+  ret = nxmutex_lock(&g_page_lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  memcpy((uint8_t *)g_page_buffer, buffer, buflen);
+
+  dest = (uint32_t *)SAMV7_US_START;
+  for (int i = 0; i < SAMV7_US_PAGE_WORDS; i++)
+    {
+      *dest++ = g_page_buffer[i];
+
+#ifdef CONFIG_ARMV7M_DCACHE_WRITETHROUGH
+          ARM_DMB();
+#endif
+    }
+
+  /* Flush the data cache to memory */
+
+  up_clean_dcache(SAMV7_US_START, SAMV7_US_START + SAMV7_US_SIZE);
+
+  ret = sam_eefc_command(EEFC_FCR_FCMD_WUS, 0);
+  if (ret < 0)
+    {
+      nxmutex_unlock(&g_page_lock);
+      return ret;
+    }
+
+  nxmutex_unlock(&g_page_lock);
+  return buflen;
+}
+
+/****************************************************************************
+ * Name: sam_get_user_signature
+ *
+ * Description:
+ *   Get bytes from user signature area.
+ *
+ * Input Parameters:
+ *   buffer  - The buffer to store user signature.
+ *   buflen  - Number of bytes to be read.
+ *
+ * Returned Value:
+ *   NONE.
+ *
+ ****************************************************************************/
+
+int sam_read_user_signature(void *buffer, size_t buflen)
+{
+  size_t nwords;
+  int ret;
+
+  ret = nxmutex_lock(&g_page_lock);
+  if (ret < 0)
+    {
+      return ret;
+    }
+
+  nwords = (buflen + sizeof(uint32_t) / sizeof(uint32_t));
+  sam_eefc_readsequence(FCMD_STUS, FCMD_SPUS, g_page_buffer, nwords);
+
+  memcpy(buffer, (uint8_t *)g_page_buffer, buflen);
+
+  nxmutex_unlock(&g_page_lock);
+  return buflen;
+}
+
+#endif /* CONFIG_SAMV7_USER_SIGNATURE */

arch/arm/src/samv7/sam_us.h

@@ -0,0 +1,81 @@
+/****************************************************************************
+ * arch/arm/src/samv7/sam_us.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __ARCH_ARM_SRC_SAMV7_SAM_US_H
+#define __ARCH_ARM_SRC_SAMV7_SAM_US_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdint.h>
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: sam_erase_user_signature
+ *
+ * Description:
+ *   Erases user signature page.
+ *
+ * Returned Value:
+ *   Zero on success, negated errno value on error.
+ *
+ ****************************************************************************/
+
+int sam_erase_user_signature(void);
+
+/****************************************************************************
+ * Name: sam_write_user_signature
+ *
+ * Description:
+ *   Writes data to user signature page.
+ *
+ * Input Parameters:
+ *   buffer  - The buffer to be written to user signature.
+ *   buflen  - Number of bytes to be written.
+ *
+ * Returned Value:
+ *   Number of written bytes on success, negated errno on error.
+ *
+ ****************************************************************************/
+
+int sam_write_user_signature(void *buffer, size_t buflen);
+
+/****************************************************************************
+ * Name: sam_get_user_signature
+ *
+ * Description:
+ *   Get bytes from user signature area.
+ *
+ * Input Parameters:
+ *   buffer  - The buffer to store user signature.
+ *   buflen  - Number of bytes to be read.
+ *
+ * Returned Value:
+ *   NONE.
+ *
+ ****************************************************************************/
+
+int sam_read_user_signature(void *buffer, size_t buflen);
+
+#endif /* __ARCH_ARM_SRC_SAMV7_SAM_US_H */