USART refactor.

1 files changed, 152 insertions, 150 deletions

diff --git a/libmaple/usart.c b/libmaple/usart.c
index 494a29f..df5e2c5 100644
--- a/libmaple/usart.c
+++ b/libmaple/usart.c
@@ -23,212 +23,214 @@
  *****************************************************************************/
 
 /**
+ * @file usart.c
  * @brief USART control routines
  */
 
-#include "libmaple.h"
-#include "rcc.h"
-#include "nvic.h"
 #include "usart.h"
 
-#define USART1_BASE    0x40013800
-#define USART2_BASE    0x40004400
-#define USART3_BASE    0x40004800
-#define UART4_BASE     0x40004C00  // High-density devices only (Maple Native)
-#define UART5_BASE     0x40005000  // High-density devices only (Maple Native)
-
-#define USART_UE       BIT(13)
-#define USART_M        BIT(12)
-#define USART_TE       BIT(3)
-#define USART_RE       BIT(2)
-#define USART_RXNEIE   BIT(5)  // read data register not empty interrupt enable
-#define USART_TC       BIT(6)
-
-/* usart descriptor table  */
-struct usart_dev usart_dev_table[] = {
-    [USART1] = {
-        .base = (usart_port*)USART1_BASE,
-        .rcc_dev_num = RCC_USART1,
-        .nvic_dev_num = NVIC_USART1
-    },
-    [USART2] = {
-        .base = (usart_port*)USART2_BASE,
-        .rcc_dev_num = RCC_USART2,
-        .nvic_dev_num = NVIC_USART2
-    },
-    [USART3] = {
-        .base = (usart_port*)USART3_BASE,
-        .rcc_dev_num = RCC_USART3,
-        .nvic_dev_num = NVIC_USART3
-    },
-#ifdef STM32_HIGH_DENSITY
-    /* TODO test */
-    [UART4] = {
-        .base = (usart_port*)UART4_BASE,
-        .rcc_dev_num = RCC_UART4,
-        .nvic_dev_num = NVIC_UART4
-    },
-    [UART5] = {
-        .base = (usart_port*)UART5_BASE,
-        .rcc_dev_num = RCC_UART5,
-        .nvic_dev_num = NVIC_UART5
-    },
-#endif
-};
-
 /*
- * Usart interrupt handlers.
+ * Devices
  */
 
-static inline void usart_irq(int usart_num) {
-#ifdef USART_SAFE_INSERT
-    /* Ignore old bytes if the user defines USART_SAFE_INSERT. */
-    rb_safe_insert(&(usart_dev_table[usart_num].rb),
-                   (uint8)((usart_dev_table[usart_num].base)->DR));
-#else
-    /* By default, push bytes around in the ring buffer. */
-    rb_push_insert(&(usart_dev_table[usart_num].rb),
-                   (uint8)((usart_dev_table[usart_num].base)->DR));
-#endif
-}
-
-/* TODO: Check the disassembly for the following functions to make
-   sure GCC inlined properly. */
-
-void __irq_usart1(void) {
-    usart_irq(USART1);
-}
-
-void __irq_usart2(void) {
-    usart_irq(USART2);
-}
-
-void __irq_usart3(void) {
-    usart_irq(USART3);
-}
+static ring_buffer usart1_rb;
+static usart_dev usart1 = {
+    .regs     = USART1_BASE,
+    .rb       = &usart1_rb,
+    .max_baud = 4500000UL,
+    .clk_id   = RCC_USART1,
+    .irq_num  = NVIC_USART1
+};
+usart_dev *USART1 = &usart1;
+
+static ring_buffer usart2_rb;
+static usart_dev usart2 = {
+    .regs     = USART2_BASE,
+    .rb       = &usart2_rb,
+    .max_baud = 2250000UL,
+    .clk_id   = RCC_USART2,
+    .irq_num  = NVIC_USART2
+};
+usart_dev *USART2 = &usart2;
+
+static ring_buffer usart3_rb;
+static usart_dev usart3 = {
+    .regs     = USART3_BASE,
+    .rb       = &usart3_rb,
+    .max_baud = 2250000UL,
+    .clk_id   = RCC_USART3,
+    .irq_num  = NVIC_USART3
+};
+usart_dev *USART3 = &usart3;
 
 #ifdef STM32_HIGH_DENSITY
-void __irq_uart4(void) {
-    usart_irq(UART4);
-}
-
-void __irq_uart5(void) {
-    usart_irq(UART5);
-}
+static ring_buffer uart4_rb;
+static usart_dev uart4 = {
+    .regs     = UART4_BASE,
+    .rb       = &uart4_rb,
+    .max_baud = 2250000UL,
+    .clk_id   = RCC_UART4,
+    .irq_num  = NVIC_UART4
+};
+usart_dev *UART4 = &uart4;
+
+static ring_buffer uart5_rb;
+static usart_dev uart5 = {
+    .regs     = UART5_BASE,
+    .rb       = &uart5_rb,
+    .max_baud = 2250000UL,
+    .clk_id   = RCC_UART5,
+    .irq_num  = NVIC_UART5
+};
+usart_dev *UART5 = &uart5;
 #endif
 
 /**
- *  @brief Enable a USART in single buffer transmission mode, multibuffer
- *     receiver mode.
- *  @param usart_num USART to be initialized
- *  @param baud Baud rate to be set at
+ * @brief Initialize a serial port.
+ * @param dev         Serial port to be initialized
  */
-void usart_init(uint8 usart_num, uint32 baud) {
-#ifdef STM32_HIGH_DENSITY
-    ASSERT(usart_num <= UART5);
-#else
-    ASSERT(usart_num <= USART3);
-#endif
-    usart_port *port;
-    ring_buffer *ring_buf;
+void usart_init(usart_dev *dev) {
+    rb_init(dev->rb, USART_RX_BUF_SIZE, dev->rx_buf);
+    rcc_clk_enable(dev->clk_id);
+    nvic_irq_enable(dev->irq_num);
+}
 
-    uint32 clk_speed;
+/**
+ * @brief Configure a serial port's baud rate.
+ *
+ * @param dev         Serial port to be configured
+ * @param clock_speed MCU clock speed, in megahertz.
+ * @param baud        Baud rate for transmit/receive.
+ */
+void usart_set_baud_rate(usart_dev *dev, uint32 clock_speed, uint32 baud) {
     uint32 integer_part;
     uint32 fractional_part;
     uint32 tmp;
 
-    port = usart_dev_table[usart_num].base;
-    rcc_clk_enable(usart_dev_table[usart_num].rcc_dev_num);
-    nvic_irq_enable(usart_dev_table[usart_num].nvic_dev_num);
-
-    /* usart1 is mad fast  */
-    clk_speed = (usart_num == USART1) ? 72000000UL : 36000000UL;
-
-    /* Initialize rx ring buffer  */
-    rb_init(&usart_dev_table[usart_num].rb,
-            sizeof (usart_dev_table[usart_num].rx_buf),
-            usart_dev_table[usart_num].rx_buf);
-
-    /* Set baud rate  */
-    integer_part = ((25 * clk_speed) / (4 * baud));
+    /* See ST RM0008 for the details on configuring the baud rate register */
+    integer_part = (25 * clock_speed) / (4 * baud);
     tmp = (integer_part / 100) << 4;
-
     fractional_part = integer_part - (100 * (tmp >> 4));
     tmp |= (((fractional_part * 16) + 50) / 100) & ((uint8)0x0F);
 
-    port->BRR = (uint16)tmp;
-
-    port->CR1 = USART_TE          |    // transmitter enable
-                USART_RE          |    // receiver enable
-                USART_RXNEIE;          // receive interrupt enable
-
-
-    /* Enable the USART and set mode to 8n1 */
-    port->CR1 |= USART_UE;
+    dev->regs->BRR = (uint16)tmp;
 }
 
 /**
- *  @brief Turn off all USARTs.
+ * @brief Enable a serial port.
+ *
+ * USART is enabled in single buffer transmission mode, multibuffer
+ * receiver mode, at the given baud rate, 8n1.
+ *
+ * Serial port must have a baud rate configured to work properly.
+ *
+ * @param dev Serial port to enable.
+ * @see usart_set_baud_rate()
  */
-void usart_disable_all() {
-    usart_disable(USART1);
-    usart_disable(USART2);
-    usart_disable(USART3);
-#ifdef STM32_HIGH_DENSITY
-    usart_disable(UART4);
-    usart_disable(UART5);
-#endif
+void usart_enable(usart_dev *dev) {
+    usart_reg_map *regs = dev->regs;
+    regs->CR1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_RXNEIE;
+    regs->CR1 |= USART_CR1_UE;
 }
 
 /**
- * @brief Turn off a USART.
- * @param USART to be disabled
+ * @brief Turn off a serial port.
+ * @param dev Serial port to be disabled
  */
-void usart_disable(uint8 usart_num) {
-    usart_port *port = usart_dev_table[usart_num].base;
+void usart_disable(usart_dev *dev) {
+    /* FIXME this misbehaves if you try to use PWM on TX afterwards */
+    usart_reg_map *regs = dev->regs;
 
-    /* TC bit must be high before disabling the usart  */
-    while((port->CR1 & USART_UE) && !(port->SR & USART_TC))
+    /* TC bit must be high before disabling the USART */
+    while((regs->CR1 & USART_CR1_UE) && !(regs->SR & USART_SR_TC))
         ;
 
     /* Disable UE */
-    port->CR1 = 0;
+    regs->CR1 = 0;
 
     /* Clean up buffer */
-    usart_reset_rx(usart_num);
+    usart_reset_rx(dev);
 }
 
+/**
+ *  @brief Call a function on each USART.
+ *  @param fn Function to call.
+ */
+void usart_foreach(void (*fn)(usart_dev *dev)) {
+    fn(USART1);
+    fn(USART2);
+    fn(USART3);
+#ifdef STM32_HIGH_DENSITY
+    fn(UART4);
+    fn(UART5);
+#endif
+}
 
 /**
- * @brief Print a null terminated string to the specified USART
- *
- * @param usart_num usart to send on
- * @param str string to send
+ * @brief Print a null-terminated string to the specified serial port.
+ * @param dev Serial port to send the string on
+ * @param str String to send
  */
-void usart_putstr(uint8 usart_num, const char* str) {
+void usart_putstr(usart_dev *dev, const char* str) {
     char ch;
 
-    while((ch = *(str++)) != '\0') {
-        usart_putc(usart_num, ch);
+    while ((ch = *(str++)) != '\0') {
+        usart_putc(dev, ch);
     }
 }
 
 /**
- * @brief Print an unsigned integer to the specified usart
+ * @brief Print an unsigned integer to the specified serial port.
  *
- * @param usart_num usart to send on
- * @param val number to print
+ * @param dev Serial port to send on
+ * @param val Number to print
  */
-void usart_putudec(uint8 usart_num, uint32 val) {
+void usart_putudec(usart_dev *dev, uint32 val) {
     char digits[12];
-    int i;
+    int i = 0;
 
-    i = 0;
     do {
         digits[i++] = val % 10 + '0';
         val /= 10;
     } while (val > 0);
+
     while (--i >= 0) {
-        usart_putc(usart_num, digits[i]);
+        usart_putc(dev, digits[i]);
     }
 }
+
+/*
+ * Interrupt handlers.
+ */
+
+static inline void usart_irq(usart_dev *dev) {
+#ifdef USART_SAFE_INSERT
+    /* Ignore new bytes if the user defines USART_SAFE_INSERT. */
+    rb_safe_insert(dev->rb, (uint8)dev->regs->DR);
+#else
+    /* By default, push bytes around in the ring buffer. */
+    rb_push_insert(dev->rb, (uint8)dev->regs->DR);
+#endif
+}
+
+void __irq_usart1(void) {
+    usart_irq(USART1);
+}
+
+void __irq_usart2(void) {
+    usart_irq(USART2);
+}
+
+void __irq_usart3(void) {
+    usart_irq(USART3);
+}
+
+#ifdef STM32_HIGH_DENSITY
+void __irq_uart4(void) {
+    usart_irq(UART4);
+}
+
+void __irq_uart5(void) {
+    usart_irq(UART5);
+}
+#endif