Prepare abstraction of C2 communication.

- f32x/c2.c: renamed to c2-om.c
- f32x/Makefile (OBJS): changed c2.o to c2-om.o

f32x/c2-om.c

@@ -0,0 +1,138 @@
+/*
+ * f32x/c2.c - Basic C2 messages
+ *
+ * Written 2008 by Werner Almesberger
+ * Copyright 2008 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include "gpio.h"
+#include "c2.h"
+
+
+/*
+ * SPI GPIOs are the same on 2410 and 2442, so this should work on GTA01 and
+ * on GTA02.
+ */
+
+#define C2CK	4, 11	/* E13 = SPI_MISO0 */
+#define C2D	4, 13	/* E12 = SPI_CLK0 */
+
+
+/* ----- Bit-level operations ---------------------------------------------- */
+
+
+static void c2_pulse(void)
+{
+    gpio_low(C2CK);
+    gpio_high(C2CK);
+}
+
+
+static void c2_send(uint32_t value, int bits)
+{
+    int i;
+
+    for (i = 0; i != bits; i++) {
+	gpio_set(C2D, (value >> i) & 1);
+	c2_pulse();
+    }
+}
+
+
+static uint32_t c2_recv(int bits)
+{
+    uint32_t v = 0;
+    int i;
+
+    for (i = 0; i != bits; i++) {
+	v |= gpio_get(C2D) << i;
+	c2_pulse();
+    }
+    return v;
+}
+
+
+/* ----- C2 Register read/write -------------------------------------------- */
+
+
+void c2_addr_write(uint8_t addr)
+{
+    c2_pulse();
+    gpio_output(C2D);
+    c2_send(C2_ADDR_WRITE, 2);
+    c2_send(addr, 8);
+    gpio_input(C2D);
+    c2_pulse();
+}
+
+
+uint8_t c2_addr_read(void)
+{
+    c2_pulse();
+    gpio_output(C2D);
+    c2_send(C2_ADDR_READ, 2);
+    gpio_input(C2D);
+    c2_pulse();
+    return c2_recv(8);
+}
+
+
+void c2_data_write(uint32_t data, int bytes)
+{
+    c2_pulse();
+    gpio_output(C2D);
+    c2_send(C2_DATA_WRITE, 2);
+    c2_send(bytes-1, 2);
+    c2_send(data, 8*bytes);
+    gpio_input(C2D);
+    c2_pulse();
+    while (!c2_recv(1));
+}
+
+
+uint32_t c2_data_read(int bytes)
+{
+    c2_pulse();
+    gpio_output(C2D);
+    c2_send(C2_DATA_READ, 2);
+    c2_send(bytes-1, 2);
+    gpio_input(C2D);
+    c2_pulse();
+    while (!c2_recv(1));
+    return c2_recv(8*bytes);
+}
+
+
+/* ----- C2 initialization ------------------------------------------------- */
+
+
+void c2_init(void)
+{
+    gpio_init();
+    gpio_input(C2D);
+    gpio_output(C2CK);
+    gpio_low(C2CK);
+    usleep(20);
+    gpio_high(C2CK);
+    usleep(2);
+}
+
+
+void c2_reset(void)
+{
+    gpio_input(C2D);
+    gpio_low(C2CK);
+    usleep(20);
+//    gpio_input(C2CK);
+    gpio_output(C2CK);
+    gpio_high(C2CK);
+}