X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=rpikern;a=blobdiff_plain;f=src%2Fmain.c;fp=src%2Fmain.c;h=47e23b6ac347bd01e06f565951bae3f6f670b033;hp=0000000000000000000000000000000000000000;hb=4cdb0feb633bc6181644704cea8f18368b5bcfd1;hpb=e3851fa5fc01560a8ab799046b7cf0d2f35f18e8

diff --git a/src/main.c b/src/main.c
new file mode 100644
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;
+}