Refactor backup (BKP) and power (PWR) routines.

7 files changed, 322 insertions, 96 deletions

diff --git a/examples/test-bkp.cpp b/examples/test-bkp.cpp
new file mode 100644
index 0000000..27f87bd
--- /dev/null
+++ b/examples/test-bkp.cpp
@@ -0,0 +1,78 @@
+#include <stdio.h>
+
+#include "wirish.h"
+#include "bkp.h"
+#include "iwdg.h"
+
+void print_bkp_contents();
+void write_to_bkp(uint16 val);
+
+void setup() {
+    pinMode(BOARD_BUTTON_PIN, INPUT);
+
+    Serial2.begin(9600);
+    Serial2.println("*** Beginning BKP test");
+
+    Serial2.println("Init...");
+    bkp_init();
+    Serial2.println("Done.");
+
+    print_bkp_contents();
+    write_to_bkp(10);
+    print_bkp_contents();
+
+    Serial2.println("Enabling backup writes.");
+    bkp_enable_writes();
+    write_to_bkp(20);
+    print_bkp_contents();
+
+    Serial2.println("Disabling backup writes.");
+    bkp_disable_writes();
+    write_to_bkp(30);
+    print_bkp_contents();
+
+    Serial2.println("Done testing backup registers; press button to enable "
+                    "independent watchdog (in order to cause a reset).");
+    waitForButtonPress(0);
+    iwdg_init(IWDG_PRE_4, 1);
+    Serial2.println();
+}
+
+void loop() {
+}
+
+void print_bkp_contents() {
+    Serial2.println("Backup data register contents:");
+    char buf[100];
+    for (int i = 1; i <= NR_BKP_REGS; i++) {
+        snprintf(buf, sizeof buf, "DR%d: %d ", i, bkp_read(i));
+        Serial2.print(buf);
+        if (i % 5 == 0) Serial2.println();
+    }
+    Serial2.println();
+}
+
+void write_to_bkp(uint16 val) {
+    Serial2.print("Attempting to write ");
+    Serial2.print(val);
+    Serial2.println(" to backup registers...");
+    for (int i = 1; i <= NR_BKP_REGS; i++) {
+        bkp_write(i, val);
+    }
+    Serial2.println("Done.");
+}
+
+__attribute__((constructor)) void premain() {
+    init();
+}
+
+int main(void) {
+    init();
+    setup();
+
+    while (1) {
+        loop();
+    }
+    return 0;
+}
+
diff --git a/libmaple/bkp.c b/libmaple/bkp.c
index e89abd0..ac9aeae 100644
--- a/libmaple/bkp.c
+++ b/libmaple/bkp.c
@@ -24,63 +24,99 @@
  * SOFTWARE.
  *****************************************************************************/
 
-#include "libmaple.h"
 #include "bkp.h"
 #include "pwr.h"
 #include "rcc.h"
 #include "util.h"
 
-/* Data register memory layout is not contiguous.  It's split up from
-   1--NR_LOW_DRS, beginning at BKP_LOW_OFFSET, through
-   (NR_LOW_DRS+1)--NR_DRS, beginning at BKP_HIGH_OFFSET. */
-#define NR_LOW_DRS 10
-#define BKP_LOW_OFFSET  0x4    /* start offset for data registers 1--10 */
-#define BKP_HIGH_OFFSET 0x40   /* start offset for data registers 11--42 */
+static inline __io uint32* data_register(uint8 reg);
 
-inline volatile uint16* reg_addr(uint8 reg) {
-    if (1 <= reg) {
-        if (reg <= NR_LOW_DRS) {
-            return (volatile uint16*)(BKP_BASE + BKP_LOW_OFFSET +
-                                      (reg - 1) * 4);
-        } else if (reg <= NR_BKP_REGS) {
-            return (volatile uint16*)(BKP_BASE + BKP_HIGH_OFFSET +
-                                      (reg - NR_LOW_DRS - 1) * 4);
-        }
-    }
-    return 0;
-}
+bkp_dev bkp = {
+    .regs = BKP_BASE,
+};
 
-void bkp_init(void) {
-    /* Set PWREN (28) and BKPEN (27) bits */
-    __set_bits(RCC_APB1ENR, BIT(28) | BIT(27));
-}
+const bkp_dev *BKP = &bkp;
 
-void bkp_disable(void) {
-    __clear_bits(RCC_APB1ENR, BIT(28) | BIT(27));
+/**
+ * @brief Initialize backup interface.
+ *
+ * Enables the power and backup interface clocks, and resets the
+ * backup device.
+ */
+void bkp_init(void) {
+    /* Don't call pwr_init(), or you'll reset the device.  We just
+     * need the clock. */
+    rcc_clk_enable(RCC_PWR);
+    rcc_clk_enable(RCC_BKP);
+    rcc_reset_dev(RCC_BKP);
 }
 
+/**
+ * Enable write access to the backup registers.  Backup interface must
+ * be initialized for subsequent register writes to work.
+ * @see bkp_init()
+ */
 void bkp_enable_writes(void) {
-    /* Set the DBP bit in PWR_CR */
-    __write(BITBAND_PERI(PWR_CR, PWR_CR_DBP), 1);
+    __write(BITBAND_PERI(&(PWR_BASE->CR), PWR_CR_DBP), 1);
 }
 
+/**
+ * Disable write access to the backup registers.
+ */
 void bkp_disable_writes(void) {
-    __write(BITBAND_PERI(PWR_CR, PWR_CR_DBP), 0);
+    __write(BITBAND_PERI(&(PWR_BASE->CR), PWR_CR_DBP), 0);
 }
 
+/**
+ * Read a value from given backup data register.
+ * @param reg Data register to read, from 1 to NR_BKP_REGS (10 on Maple).
+ */
 uint16 bkp_read(uint8 reg) {
-    volatile uint16* addr = reg_addr(reg);
-    if (addr != 0) {
-        return *addr;
+    __io uint32* dr = data_register(reg);
+    if (!dr) {
+        ASSERT(0);                  /* nonexistent register */
+        return 0;
     }
-    ASSERT(0);                  /* nonexistent register */
-    return 0;
+    return (uint16)*dr;
 }
 
+/**
+ * @brief Write a value to given data register.
+ *
+ * Write access to backup registers must be enabled.
+ *
+ * @param reg Data register to write, from 1 to NR_BKP_REGS (10 on Maple).
+ * @param val Value to write into the register.
+ * @see bkp_enable_writes()
+ */
 void bkp_write(uint8 reg, uint16 val) {
-    volatile uint16* addr = reg_addr(reg);
-    if (addr != 0) {
-        *addr = val;
+    __io uint32* dr = data_register(reg);
+    if (!dr) {
+        ASSERT(0);                  /* nonexistent register */
+        return;
+    }
+    *dr = (uint32)val;
+}
+
+/*
+ * Data register memory layout is not contiguous. It's split up from
+ * 1--NR_LOW_DRS, beginning at BKP_BASE->DR1, through to
+ * (NR_LOW_DRS+1)--NR_BKP_REGS, beginning at BKP_BASE->DR10.
+ */
+#define NR_LOW_DRS 10
+
+static inline __io uint32* data_register(uint8 reg) {
+    if (reg < 1 || reg > NR_BKP_REGS) {
+        return 0;
+    }
+
+#if NR_BKP_REGS == NR_LOW_DRS
+    return (uint32*)BKP_BASE + reg;
+#else
+    if (reg <= NR_LOW_DRS) {
+        return (uint32*)BKP_BASE + reg;
+    } else {
+        return (uint32*)&(BKP_BASE->DR11) + (reg - NR_LOW_DRS - 1);
     }
-    ASSERT(0);                  /* nonexistent register */
+#endif
 }
diff --git a/libmaple/bkp.h b/libmaple/bkp.h
index 9ad4c41..ce8e6c7 100644
--- a/libmaple/bkp.h
+++ b/libmaple/bkp.h
@@ -32,51 +32,83 @@
 #ifndef _BKP_H_
 #define _BKP_H_
 
+#include "libmaple.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#define BKP_BASE        0x40006C00
-#define BKP_RTCCR       (BKP_BASE + 0x2C)
-#define BKP_CR          (BKP_BASE + 0x30)
-#define BKP_CSR         (BKP_BASE + 0x34)
-
-/**
- * Initialize backup interface. This function enables the power and
- * backup interface clocks.  It does not enable write access to the
- * backup registers.
- */
-void bkp_init(void);
+typedef struct bkp_reg_map {
+    const uint32 RESERVED1;
+    __io uint32 DR1;            ///< Data register 1
+    __io uint32 DR2;            ///< Data register 2
+    __io uint32 DR3;            ///< Data register 3
+    __io uint32 DR4;            ///< Data register 4
+    __io uint32 DR5;            ///< Data register 5
+    __io uint32 DR6;            ///< Data register 6
+    __io uint32 DR7;            ///< Data register 7
+    __io uint32 DR8;            ///< Data register 8
+    __io uint32 DR9;            ///< Data register 9
+    __io uint32 DR10;           ///< Data register 10
+    __io uint32 RTCCR;          ///< RTC control register
+    __io uint32 CR;             ///< Control register
+    __io uint32 CSR;            ///< Control and status register
+#if NR_BKP_REGS > 10
+    const uint32 RESERVED2;
+    const uint32 RESERVED3;
+    __io uint32 DR11;           ///< Data register 11
+    __io uint32 DR12;           ///< Data register 12
+    __io uint32 DR13;           ///< Data register 13
+    __io uint32 DR14;           ///< Data register 14
+    __io uint32 DR15;           ///< Data register 15
+    __io uint32 DR16;           ///< Data register 16
+    __io uint32 DR17;           ///< Data register 17
+    __io uint32 DR18;           ///< Data register 18
+    __io uint32 DR19;           ///< Data register 19
+    __io uint32 DR20;           ///< Data register 20
+    __io uint32 DR21;           ///< Data register 21
+    __io uint32 DR22;           ///< Data register 22
+    __io uint32 DR23;           ///< Data register 23
+    __io uint32 DR24;           ///< Data register 24
+    __io uint32 DR25;           ///< Data register 25
+    __io uint32 DR26;           ///< Data register 26
+    __io uint32 DR27;           ///< Data register 27
+    __io uint32 DR28;           ///< Data register 28
+    __io uint32 DR29;           ///< Data register 29
+    __io uint32 DR30;           ///< Data register 30
+    __io uint32 DR31;           ///< Data register 31
+    __io uint32 DR32;           ///< Data register 32
+    __io uint32 DR33;           ///< Data register 33
+    __io uint32 DR34;           ///< Data register 34
+    __io uint32 DR35;           ///< Data register 35
+    __io uint32 DR36;           ///< Data register 36
+    __io uint32 DR37;           ///< Data register 37
+    __io uint32 DR38;           ///< Data register 38
+    __io uint32 DR39;           ///< Data register 39
+    __io uint32 DR40;           ///< Data register 40
+    __io uint32 DR41;           ///< Data register 41
+    __io uint32 DR42;           ///< Data register 42
+#endif
+} bkp_reg_map;
 
-/** Disable power and backup interface clocks. */
-void bkp_disable(void);
+typedef struct bkp_dev {
+    bkp_reg_map *regs;
+} bkp_dev;
 
 /**
- * Enable write access to the backup registers.  Backup interface must
- * be initialized for subsequent register writes to work.
- * @see bkp_init()
+ * Backup device.
  */
-void bkp_enable_writes(void);
+extern const bkp_dev *BKP;
 
-/**
- * Disable write access to the backup registers.  Does not disable
- * backup interface clocks.
+/*
+ * Backup peripheral base.
  */
-void bkp_disable_writes(void);
+#define BKP_BASE        ((bkp_reg_map*)0x40006C00)
 
-/**
- * Read a value from given backup data register.
- * @param reg Data register to read, from 1 to NR_BKP_REGS (10 on Maple).
- */
+void bkp_init(void);
+void bkp_enable_writes(void);
+void bkp_disable_writes(void);
 uint16 bkp_read(uint8 reg);
-
-/**
- * Write a value to given data register.  Backup interface must have
- * been previously initialized, and write access to backup registers
- * must be enabled.
- * @param reg Data register to write, from 1 to NR_BKP_REGS (10 on Maple).
- * @param val Value to write into the register.
- */
 void bkp_write(uint8 reg, uint16 val);
 
 #ifdef __cplusplus
diff --git a/libmaple/pwr.c b/libmaple/pwr.c
new file mode 100644
index 0000000..b43193e
--- /dev/null
+++ b/libmaple/pwr.c
@@ -0,0 +1,42 @@
+/******************************************************************************
+ * The MIT License
+ *
+ * Copyright (c) 2011 LeafLabs, LLC.
+ *
+ * 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 "pwr.h"
+#include "rcc.h"
+
+pwr_dev pwr = {
+    .regs = PWR_BASE;
+};
+
+const pwr_dev *PWR = &pwr;
+
+/**
+ * Enables the power interface clock, and resets the power device.
+ */
+void pwr_init(void) {
+    rcc_clk_enable(RCC_PWR);
+    rcc_reset_dev(RCC_PWR);
+}
diff --git a/libmaple/pwr.h b/libmaple/pwr.h
index 96a8356..5ff815d 100644
--- a/libmaple/pwr.h
+++ b/libmaple/pwr.h
@@ -29,18 +29,52 @@
  * @brief Power control (PWR) defines.
  */
 
-#define PWR_BASE 0x40007000
-
-#define PWR_CR      (PWR_BASE + 0x0)
-#define PWR_CR_DBP  8 /* Disable backup domain write protection bit */
-#define PWR_CR_PVDE 4 /* Power voltage detector enable bit */
-#define PWR_CR_CSBF 3 /* Clear standby flag bit */
-#define PWR_CR_CWUF 2 /* Clear wakeup flag bit */
-#define PWR_CR_PDDS 1 /* Power down deepsleep bit */
-#define PWR_CR_LPDS 0 /* Low-power deepsleep bit */
-
-#define PWR_CSR      (PWR_BASE + 0x4)
-#define PWR_CSR_EWUP 8          /* Enable wakeup pin bit */
-#define PWR_CSR_PVDO 2          /* PVD output bit */
-#define PWR_CSR_SBF  1          /* Standby flag bit */
-#define PWR_CSR_WUF  0          /* Wakeup flag bit */
+#include "libmaple.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Power interface register map. */
+typedef struct pwr_reg_map {
+    __io uint32 CR;      /**< Control register */
+    __io uint32 CSR;     /**< Control and status register */
+} pwr_reg_map;
+
+/*
+ * Power peripheral base.
+ */
+#define PWR_BASE    ((pwr_reg_map*)0x40007000)
+
+/** Power interface device. */
+typedef struct pwr_dev {
+    pwr_reg_map *regs;
+} pwr_dev;
+
+/**
+ * Power device.
+ */
+extern const pwr_dev *PWR;
+/*
+ * Register bit definitions
+ */
+
+/* Control register */
+#define PWR_CR_DBP  8 /**< Disable backup domain write protection bit */
+#define PWR_CR_PVDE 4 /**< Power voltage detector enable bit */
+#define PWR_CR_CSBF 3 /**< Clear standby flag bit */
+#define PWR_CR_CWUF 2 /**< Clear wakeup flag bit */
+#define PWR_CR_PDDS 1 /**< Power down deepsleep bit */
+#define PWR_CR_LPDS 0 /**< Low-power deepsleep bit */
+
+/* Control and status register */
+#define PWR_CSR_EWUP 8          /**< Enable wakeup pin bit */
+#define PWR_CSR_PVDO 2          /**< PVD output bit */
+#define PWR_CSR_SBF  1          /**< Standby flag bit */
+#define PWR_CSR_WUF  0          /**< Wakeup flag bit */
+
+void pwr_init(void);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/libmaple/rcc.c b/libmaple/rcc.c
index a9d7c96..2841af3 100644
--- a/libmaple/rcc.c
+++ b/libmaple/rcc.c
@@ -74,6 +74,8 @@ static const struct rcc_dev_info rcc_dev_table[] = {
     [RCC_DAC]    = { .clk_domain = APB1, .line_num = 29 }, // High-density only
     [RCC_DMA1]   = { .clk_domain = AHB,  .line_num = 0 },
     [RCC_DMA2]   = { .clk_domain = AHB,  .line_num = 1 }, // High-density only
+    [RCC_PWR]    = { .clk_domain = APB1, .line_num = 28},
+    [RCC_BKP]    = { .clk_domain = APB1, .line_num = 27}
 };
 
 /**
@@ -117,18 +119,18 @@ void rcc_clk_init(uint32 sysclk_src, uint32 pll_src, uint32 pll_mul) {
 
 /**
  * @brief Turn on the clock line on a device
- * @param dev_num device to turn on
+ * @param device Clock ID of the device to turn on.
  */
-void rcc_clk_enable(uint32 dev_num) {
+void rcc_clk_enable(rcc_clk_id device) {
     static const uint32 enable_regs[] = {
         [APB1] = RCC_APB1ENR,
         [APB2] = RCC_APB2ENR,
         [AHB] = RCC_AHBENR,
     };
 
-    uint8 clk_domain = rcc_dev_table[dev_num].clk_domain;
+    uint8 clk_domain = rcc_dev_table[device].clk_domain;
 
-    __set_bits(enable_regs[clk_domain], BIT(rcc_dev_table[dev_num].line_num));
+    __set_bits(enable_regs[clk_domain], BIT(rcc_dev_table[device].line_num));
 }
 
 /**
@@ -154,16 +156,16 @@ void rcc_set_prescaler(uint32 prescaler, uint32 divider) {
 
 /**
  * @brief reset a device
- * @param dev_num device to reset
+ * @param device Clock ID of the device to reset.
  */
-void rcc_reset_dev(uint32 dev_num) {
+void rcc_reset_dev(rcc_clk_id device) {
     static const uint32 reset_regs[] = {
         [APB1] = RCC_APB1RSTR,
         [APB2] = RCC_APB2RSTR,
     };
 
-    uint8 clk_domain = rcc_dev_table[dev_num].clk_domain;
+    uint8 clk_domain = rcc_dev_table[device].clk_domain;
 
-    __set_bits(reset_regs[clk_domain], BIT(rcc_dev_table[dev_num].line_num));
-    __clear_bits(reset_regs[clk_domain], BIT(rcc_dev_table[dev_num].line_num));
+    __set_bits(reset_regs[clk_domain], BIT(rcc_dev_table[device].line_num));
+    __clear_bits(reset_regs[clk_domain], BIT(rcc_dev_table[device].line_num));
 }
diff --git a/libmaple/rcc.h b/libmaple/rcc.h
index 5daca57..410ab8b 100644
--- a/libmaple/rcc.h
+++ b/libmaple/rcc.h
@@ -178,12 +178,14 @@ typedef enum {
     RCC_DAC,         // High-density devices only (Maple Native)
     RCC_DMA1,
     RCC_DMA2,        // High-density devices only (Maple Native)
+    RCC_PWR,
+    RCC_BKP,
 } rcc_clk_id;
 
 
 void rcc_clk_init(uint32 sysclk_src, uint32 pll_src, uint32 pll_mul);
-void rcc_clk_enable(uint32 dev);
-void rcc_reset_dev(uint32 dev);
+void rcc_clk_enable(rcc_clk_id device);
+void rcc_reset_dev(rcc_clk_id device);
 void rcc_set_prescaler(uint32 prescaler, uint32 divider);
 
 #ifdef __cplusplus