cpu/samd0: added flashpage driver implemenation

cpu/sam0_common/include/cpu_conf.h

@@ -36,6 +36,16 @@ extern "C" {
 #define CPU_FLASH_BASE                  FLASH_ADDR
 /** @} */
 
+/**
+ * @brief   Flash page configuration
+ * @{
+ */
+/* a flashpage in RIOT is mapped to a flash row on the SAM0s */
+#define FLASHPAGE_SIZE      (256U)
+/* one SAM0 row contains 4 SAM0 pages -> 4x the amount of RIOT flashpages */
+#define FLASHPAGE_NUMOF     (FLASH_NB_OF_PAGES / 4)
+/** @} */
+
 #ifdef __cplusplus
 }
 #endif

cpu/sam0_common/periph/flashpage.c

+/*
+ * Copyright (C) 2016 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     cpu_sam0_common
+ * @{
+ *
+ * @file
+ * @brief       Low-level flash page driver implementation
+ *
+ * The sam0 has its flash memory organized in pages and rows, where each row
+ * consists of 4 pages. While pages are writable one at a time, it is only
+ * possible to delete a complete row. This implementation abstracts this
+ * behavior by only writing complete rows at a time, so the FLASH_PAGE_SIZE we
+ * use in RIOT is actually the row size as specified in the datasheet.
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include "cpu.h"
+#include "assert.h"
+#include "periph/flashpage.h"
+
+#define NVMCTRL_PAC_BIT     (0x00000002)
+
+void flashpage_write(int page, void *data)
+{
+    assert(page < FLASHPAGE_NUMOF);
+
+    uint32_t *page_addr = (uint32_t *)flashpage_addr(page);
+
+    /* remove peripheral access lock for the NVMCTRL peripheral */
+#ifdef CPU_FAM_SAML21
+    PAC->WRCTRL.reg = (PAC_WRCTRL_KEY_CLR | ID_NVMCTRL);
+#else
+    if (PAC1->WPSET.reg & NVMCTRL_PAC_BIT) {
+        PAC1->WPCLR.reg = NVMCTRL_PAC_BIT;
+    }
+#endif
+
+    /* erase given page (the ADDR register uses 16-bit addresses) */
+    NVMCTRL->ADDR.reg = (((uint32_t)page_addr) >> 1);
+    NVMCTRL->CTRLA.reg = (NVMCTRL_CTRLA_CMDEX_KEY | NVMCTRL_CTRLA_CMD_ER);
+    while (!(NVMCTRL->INTFLAG.reg & NVMCTRL_INTFLAG_READY)) {}
+
+    /* write data to page */
+    if (data != NULL) {
+        uint32_t *data_addr = (uint32_t *)data;
+        NVMCTRL->CTRLA.reg = (NVMCTRL_CTRLA_CMDEX_KEY | NVMCTRL_CTRLA_CMD_PBC);
+        for (unsigned i = 0; i < (FLASHPAGE_SIZE / 4); i++) {
+            *page_addr++ = data_addr[i];
+        }
+        NVMCTRL->CTRLA.reg = (NVMCTRL_CTRLA_CMDEX_KEY | NVMCTRL_CTRLA_CMD_WP);
+    }
+}