mulle: Initialize NVRAM storage at boot, update boot counter

The boot counter is incremented on each boot. Still missing is an
interface for reading the boot counter from an application.

boards/mulle/Makefile.dep

@@ -6,6 +6,9 @@ endif
 # The RTT clock drives the core clock in the default configuration
 FEATURES_REQUIRED += periph_rtt
 
+# The RTT clock drives the core clock in the default configuration
+FEATURES_REQUIRED += periph_rtt
+
 # The Mulle uses NVRAM to store persistent variables, such as boot count.
-#~ USEMODULE += nvram_spi
-# Uncomment above when #2353 is merged.
+USEMODULE += nvram_spi
+FEATURES_REQUIRED += periph_spi

boards/mulle/board.c

@@ -26,6 +26,16 @@
 #include "periph/gpio.h"
 #include "periph/uart.h"
 #include "periph/rtt.h"
+#include "periph/spi.h"
+#include "nvram-spi.h"
+
+static nvram_t mulle_nvram_dev;
+nvram_t *mulle_nvram = &mulle_nvram_dev;
+static nvram_spi_params_t nvram_spi_params = {
+        .spi = MULLE_NVRAM_SPI_DEV,
+        .cs = MULLE_NVRAM_SPI_CS,
+        .address_count = MULLE_NVRAM_SPI_ADDRESS_COUNT,
+};
 
 /**
  * @brief Initialize the boards on-board LEDs
@@ -50,9 +60,12 @@ static inline void set_safe_clock_dividers(void);
 /** @brief Set the FLL source clock to RTC32k */
 static inline void set_fll_source(void);
 
+static void increase_boot_count(void);
+static int mulle_nvram_init(void);
 
 void board_init(void)
 {
+    int status;
     /* initialize the boards LEDs, this is done first for debugging purposes */
     leds_init();
 
@@ -60,6 +73,12 @@ void board_init(void)
     power_pins_init();
 
     /* Turn on Vperiph for peripherals */
+    /*
+     * By turning on Vperiph first, and before waiting for the clocks to
+     * stabilize, we will have used enough time to have let the FRAM start up
+     * properly when we want to access it later without having to add any extra
+     * delays.
+     */
     gpio_set(MULLE_POWER_VPERIPH);
 
     /* Turn on AVDD for reading voltages */
@@ -98,6 +117,17 @@ void board_init(void)
 
     /* initialize the CPU */
     cpu_init();
+
+    LED_YELLOW_ON;
+
+    /* Initialize NVRAM */
+    status = mulle_nvram_init();
+    if (status == 0) {
+        /* Increment boot counter */
+        increase_boot_count();
+    }
+
+    LED_GREEN_ON;
 }
 
 /**
@@ -168,3 +198,57 @@ static inline void set_fll_source(void)
 #error Unknown K60 CPU revision
 #endif
 }
+
+static int mulle_nvram_init(void)
+{
+    union {
+        uint32_t u32;
+        uint8_t  u8[sizeof(uint32_t)];
+    } rec;
+    rec.u32 = 0;
+
+    if (spi_init_master(MULLE_NVRAM_SPI_DEV, SPI_CONF_FIRST_RISING, SPI_SPEED_5MHZ) != 0) {
+        return -1;
+    }
+
+    if (nvram_spi_init(mulle_nvram, &nvram_spi_params, MULLE_NVRAM_CAPACITY) != 0) {
+        return -2;
+    }
+
+    if (mulle_nvram->read(mulle_nvram, &rec.u8[0], MULLE_NVRAM_MAGIC, sizeof(rec.u32)) != sizeof(rec.u32)) {
+        return -3;
+    }
+
+    if (rec.u32 != MULLE_NVRAM_MAGIC_EXPECTED) {
+        int i;
+        union {
+            uint64_t u64;
+            uint8_t  u8[sizeof(uint64_t)];
+        } zero;
+        zero.u64 = 0;
+        for (i = 0; i < MULLE_NVRAM_CAPACITY; i += sizeof(zero)) {
+            if (mulle_nvram->write(mulle_nvram, &zero.u8[0], i, sizeof(zero.u64)) != sizeof(zero.u64)) {
+                return -4;
+            }
+        }
+        rec.u32 = MULLE_NVRAM_MAGIC_EXPECTED;
+        if (mulle_nvram->write(mulle_nvram, &rec.u8[0], MULLE_NVRAM_MAGIC, sizeof(rec.u32)) != sizeof(rec.u32)) {
+            return -5;
+        }
+    }
+    return 0;
+}
+
+static void increase_boot_count(void)
+{
+    union {
+        uint32_t u32;
+        uint8_t  u8[sizeof(uint32_t)];
+    } rec;
+    rec.u32 = 0;
+    if (mulle_nvram->read(mulle_nvram, &rec.u8[0], MULLE_NVRAM_BOOT_COUNT, sizeof(rec.u32)) != sizeof(rec.u32)) {
+        return;
+    }
+    ++rec.u32;
+    mulle_nvram->write(mulle_nvram, &rec.u8[0], MULLE_NVRAM_BOOT_COUNT, sizeof(rec.u32));
+}

boards/mulle/include/board.h

@@ -23,6 +23,7 @@
 
 #include "cpu.h"
 #include "periph_conf.h"
+#include "mulle-nvram.h"
 
 /* Use the on board RTC 32kHz clock for LPTMR clocking. */
 #undef LPTIMER_CLKSRC
@@ -120,6 +121,17 @@ void board_init(void);
 #define MULLE_POWER_VSEC    GPIO_5 /**< VSEC enable pin */
 /** @} */
 
+/**
+ * @name Mulle NVRAM hardware configuration
+ */
+/** @{ */
+/** FRAM SPI bus, SPI_2 in RIOT is mapped to hardware bus SPI0, see periph_conf.h */
+#define MULLE_NVRAM_SPI_DEV           SPI_2
+#define MULLE_NVRAM_SPI_CS            GPIO_16 /**< FRAM CS pin */
+#define MULLE_NVRAM_CAPACITY          512     /**< FRAM size, in bytes */
+#define MULLE_NVRAM_SPI_ADDRESS_COUNT 1       /**< FRAM addressing size, in bytes */
+/** @} */
+
 /**
  * @name K60 clock dividers
  */

boards/mulle/include/mulle-nvram.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) 2015 Eistec AB
+ *
+ * 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.
+ */
+
+#ifndef MULLE_NVRAM_H_
+#define MULLE_NVRAM_H_
+
+#include "nvram.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @ingroup     board_mulle
+ * @{
+ *
+ * @file
+ * @brief       NVRAM offsets for the Eistec Mulle IoT board
+ *
+ * @author      Joakim Gebart <joakim.gebart@eistec.se>
+ */
+
+typedef enum mulle_nvram_address {
+    /** @brief NVRAM magic number, used to identify an initialized FRAM device. */
+    MULLE_NVRAM_MAGIC        = 0x0000,
+    /** @brief Reboot counter */
+    MULLE_NVRAM_BOOT_COUNT = 0x0004,
+} mulle_nvram_address_t;
+
+#define MULLE_NVRAM_MAGIC_EXPECTED (0x4c4c554dul) /* == "MULL" in ASCII */
+
+extern nvram_t *mulle_nvram;
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* MULLE_NVRAM_H_ */