startup and debug led

[rpikern] / src / main.c

diff --git a/src/main.c b/src/main.c
new file mode 100644 (file)
index 0000000..47e23b6
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,92 @@
+/* mailbox registers (MB 0: input  1: output)
+ * function | MB 0 | MB 1
+ *  rd/wr   | 00   | 20      ( upper 28: data, lower 4: channel )
+ *  peek    | 10   | 30
+ *  sender  | 14   | 34
+ *  status  | 18   | 38
+ *  config  | 1c   | 3c
+ *
+ * channel 1: framebuffer
+ * channel 8: request
+ *
+ * read: read status reg loop while empty flag is set
+ * write: read status loop while full flag is set
+ */
+#include <string.h>
+#include <stdint.h>
+
+#ifdef RPI1
+#define IOBASEADDR     0x20000000
+#else
+#define IOBASEADDR     0x3f000000
+#endif
+
+#define phys2bus(addr) ((addr) | 0x40000000)
+#define bus2phys(addr) ((addr) & 0x3fffffff)
+
+#define IOREG_ADDR(x)  (IOBASEADDR | (x))
+#define REG_MB_READ            *((volatile uint32_t*)IOREG_ADDR(0xb880))
+#define REG_MB_STAT            *((volatile uint32_t*)IOREG_ADDR(0xb898))
+#define REG_MB_WRITE   *((volatile uint32_t*)IOREG_ADDR(0xb8a0))
+
+#define MB_STAT_FULL   0x80000000
+#define MB_STAT_EMPTY  0x40000000
+
+#define MB_CHAN_FRAMEBUF       1
+#define MB_CHAN_PROP           8
+
+#define PROP_CODE_REQ  0
+#define PROP_RESP_OK   0x80000000
+
+#define PROP_TAG_END           0
+#define PROP_TAG_BLANKSCR      0x40002
+
+int prop_blankscr(int onoff);
+
+uint32_t mb_read(int chan);
+void mb_write(int chan, uint32_t val);
+
+int main(void)
+{
+       prop_blankscr(1);
+
+       return 0;
+}
+
+static uint32_t propbuf[64] __attribute__((aligned(16)));
+
+int prop_blankscr(int onoff)
+{
+       uint32_t *pb = propbuf;
+
+       *pb++ = 0;
+       *pb++ = 0;
+       *pb++ = PROP_TAG_BLANKSCR;
+       *pb++ = 4;      /* data size */
+       *pb++ = PROP_CODE_REQ;
+       *pb++ = onoff ? 1 : 0;
+       *pb++ = PROP_TAG_END;
+       *pb++ = 0;      /* padding */
+       propbuf[0] = (char*)pb - (char*)propbuf;
+
+       mb_write(MB_CHAN_PROP, (uint32_t)propbuf >> 4);
+       mb_read(MB_CHAN_PROP);
+
+       return propbuf[1] == PROP_RESP_OK ? 0 : -1;
+}
+
+uint32_t mb_read(int chan)
+{
+       uint32_t val;
+       do {
+               while(REG_MB_STAT & MB_STAT_EMPTY);
+               val = REG_MB_READ;
+       } while((val & 0xf) != chan);
+       return val >> 4;
+}
+
+void mb_write(int chan, uint32_t val)
+{
+       while(REG_MB_STAT & MB_STAT_FULL);
+       REG_MB_WRITE = (val << 4) | chan;
+}