Feat: lab 3 w/o adv 2

bootloader/lib/uart.c

@@ -0,0 +1,133 @@
+#include <uart.h>
+#include <gpio.h>
+#include <stddef.h>
+
+/* Auxilary mini UART registers */
+#define AUX_ENABLE      ((volatile unsigned int*)(MMIO_BASE + 0x00215004))
+#define AUX_MU_IO       ((volatile unsigned int*)(MMIO_BASE + 0x00215040))
+#define AUX_MU_IER      ((volatile unsigned int*)(MMIO_BASE + 0x00215044))
+#define AUX_MU_IIR      ((volatile unsigned int*)(MMIO_BASE + 0x00215048))
+#define AUX_MU_LCR      ((volatile unsigned int*)(MMIO_BASE + 0x0021504C))
+#define AUX_MU_MCR      ((volatile unsigned int*)(MMIO_BASE + 0x00215050))
+#define AUX_MU_LSR      ((volatile unsigned int*)(MMIO_BASE + 0x00215054))
+#define AUX_MU_MSR      ((volatile unsigned int*)(MMIO_BASE + 0x00215058))
+#define AUX_MU_SCRATCH  ((volatile unsigned int*)(MMIO_BASE + 0x0021505C))
+#define AUX_MU_CNTL     ((volatile unsigned int*)(MMIO_BASE + 0x00215060))
+#define AUX_MU_STAT     ((volatile unsigned int*)(MMIO_BASE + 0x00215064))
+#define AUX_MU_BAUD     ((volatile unsigned int*)(MMIO_BASE + 0x00215068))
+
+int is_uart_inited = 0;
+
+/**
+ * Set baud rate and characteristics (115200 8N1) and map to GPIO
+ */
+void uart_init()
+{
+  register unsigned int r;
+
+  /* initialize UART */
+  *AUX_ENABLE |= 1;       // enable UART1, AUX mini uart
+  *AUX_MU_CNTL = 0;
+  *AUX_MU_LCR  = 3;       // 8 bits
+  *AUX_MU_MCR  = 0;
+  *AUX_MU_IER  = 0;
+  *AUX_MU_IIR  = 0xc6;    // disable interrupts
+  *AUX_MU_BAUD = 270;    // 115200 baud
+  /* map UART1 to GPIO pins */
+  r = *GPFSEL1;
+  r &= ~((7 << 12) | (7 << 15)); // gpio14, gpio15
+  r |= (2 << 12) | (2 << 15);    // alt5
+  *GPFSEL1 = r;
+  *GPPUD = 0;            // enable pins 14 and 15
+  r = 150; while (r--) { asm volatile("nop"); }
+  *GPPUDCLK0 = (1 << 14) | (1 << 15);
+  r = 150; while (r--) { asm volatile("nop"); }
+  *GPPUDCLK0 = 0;        // flush GPIO setup
+  *AUX_MU_CNTL = 3;      // enable Tx, Rx
+
+  is_uart_inited = 1;
+}
+
+/**
+ * Send a character
+ */
+void uart_send(unsigned int c)
+{
+  /* wait until we can send */
+  do { asm volatile("nop"); } while (!(*AUX_MU_LSR & 0x20));
+  /* write the character to the buffer */
+  *AUX_MU_IO = c;
+}
+
+uint8_t uart_getb()
+{
+  uint8_t r;
+  /* wait until something is in the buffer */
+  do { asm volatile("nop"); } while (!(*AUX_MU_LSR & 0x01));
+  /* read it and return */
+  r = (uint8_t)(*AUX_MU_IO);
+
+  return r;
+}
+
+/**
+ * Receive a character
+ */
+char uart_getc()
+{
+  char r = (char)uart_getb();
+
+  /* convert carrige return to newline */
+  return r == '\r' ? '\n' : r;
+}
+
+/**
+ * Display a string
+ */
+void uart_puts(const char *s)
+{
+  while (*s) {
+    /* convert newline to carrige return + newline */
+    if(*s == '\n')
+      uart_send('\r');
+    uart_send(*s++);
+  }
+}
+
+/**
+ * Display a binary value in hexadecimal
+ */
+void uart_hex(uint64_t d)
+{
+  unsigned int n;
+  for (int c = 28; c >= 0; c -= 4) {
+    // get highest tetrad
+    n = (d >> c) & 0xF;
+    // 0-9 => '0'-'9', 10-15 => 'A'-'F'
+    n += n > 9 ? 0x37 : 0x30;
+    uart_send(n);
+  }
+}
+
+void uart_int(int d)
+{
+  unsigned int buf[11];
+  int size = 0;
+ 
+  if (d == 0) {
+    uart_send((unsigned int)'0');
+    return;
+  }
+
+  int is_neg = (d < 0);
+
+  while (d != 0) {
+    buf[size++] = '0' + d % 10;
+    d /= 10;
+  }
+
+  if (is_neg)
+    uart_send((unsigned int)'-');
+  while (size--)
+    uart_send(buf[size]);
+}