doc/examples/barectf-tracepoint/barectf-platform-qemu-arm-uart.c

   1 #include <stdint.h>
   2 #include <stdio.h>
   3 #include <barectf.h>
   4
   5 #include "barectf-platform-qemu-arm-uart.h"
   6
   7 #define BUF_SIZE                4096
   8 #define TIMER_CTRL_32BIT        (1 << 1)
   9 #define TIMER_CTRL_ENABLE       (1 << 7)
  10
  11 volatile uint32_t * const uart0 = (uint32_t *) 0x101f1000;
  12 volatile uint32_t * const uart1 = (uint32_t *) 0x101f2000;
  13 volatile uint32_t * const timer0_ctrl = (uint32_t *) 0x101e2008;
  14 volatile uint32_t * const timer0_value = (uint32_t *) 0x101e2004;
  15
  16 static struct barectf_default_ctx barectf_ctx;
  17
  18 static uint8_t buf[BUF_SIZE];
  19
  20 static uint64_t get_clock(void* data)
  21 {
  22         return (uint64_t) -*timer0_value;
  23 }
  24
  25 static void flush_packet(void)
  26 {
  27         size_t i;
  28
  29         /* flush packet to UART 1 */
  30         for (i = 0; i < BUF_SIZE; ++i) {
  31                 *uart1 = (uint32_t) buf[i];
  32         }
  33 }
  34
  35 static int is_backend_full(void *data)
  36 {
  37         return 0;
  38 }
  39
  40 static void open_packet(void *data)
  41 {
  42         barectf_default_open_packet(&barectf_ctx);
  43 }
  44
  45 static void close_packet(void *data)
  46 {
  47         /* close packet now */
  48         barectf_default_close_packet(&barectf_ctx);
  49
  50         /* flush current packet */
  51         flush_packet();
  52 }
  53
  54 void barectf_platform_qemu_arm_uart_init(void)
  55 {
  56         struct barectf_platform_callbacks cbs = {
  57                 .default_clock_get_value = get_clock,
  58                 .is_backend_full = is_backend_full,
  59                 .open_packet = open_packet,
  60                 .close_packet = close_packet,
  61         };
  62
  63         /* enable/start timer (clock source) */
  64         *timer0_ctrl |= TIMER_CTRL_32BIT | TIMER_CTRL_ENABLE;
  65
  66         /* initialize barectf context */
  67         barectf_init(&barectf_ctx, buf, BUF_SIZE, cbs, NULL);
  68
  69         /* open first packet */
  70         open_packet(NULL);
  71
  72         /* indicate that tracing is starting */
  73         puts("tracing: starting");
  74 }
  75
  76 void barectf_platform_qemu_arm_uart_fini(void)
  77 {
  78         /* close last packet if it contains at least one event */
  79         if (barectf_packet_is_open(&barectf_ctx) &&
  80                         !barectf_packet_is_empty(&barectf_ctx)) {
  81                 close_packet(NULL);
  82         }
  83
  84         /* indicate that tracing is done */
  85         puts("tracing: done");
  86 }
  87
  88 struct barectf_default_ctx *barectf_platform_qemu_arm_uart_get_barectf_ctx()
  89 {
  90         return &barectf_ctx;
  91 }
  92
  93 #define STDOUT  1
  94 #define STDERR  2
  95
  96 /* custom write "syscall" for newlib's stdio: write to UART 0 */
  97 int _write(int file, char *ptr, int len) {
  98         if (file == STDOUT || file == STDERR) {
  99                 int i;
 100
 101                 for (i = 0; i < len; i++) {
 102                         *uart0 = (uint32_t) ptr[i];
 103                 }
 104         }
 105
 106         return 0;
 107 }