DS1338 RTC

Implement MAXIM SD1338 RTC+NVRAM.

Signed-off-by: Paul Brook <paul@codesourcery.com>

1 files changed, 132 insertions, 0 deletions

diff --git a/hw/ds1338.c b/hw/ds1338.c
new file mode 100644
index 0000000..6f5ae5e
--- /dev/null
+++ b/hw/ds1338.c
@@ -0,0 +1,132 @@
+/*
+ * MAXIM DS1338 I2C RTC+NVRAM
+ *
+ * Copyright (c) 2009 CodeSourcery.
+ * Written by Paul Brook
+ *
+ * This code is licenced under the GNU GPL v2.
+ */
+
+#include "i2c.h"
+
+typedef struct {
+    i2c_slave i2c;
+    time_t offset;
+    struct tm now;
+    uint8_t nvram[56];
+    int ptr;
+    int addr_byte;
+} DS1338State;
+
+static void ds1338_event(i2c_slave *i2c, enum i2c_event event)
+{
+    DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
+
+    switch (event) {
+    case I2C_START_RECV:
+        qemu_get_timedate(&s->now, s->offset);
+        s->nvram[0] = to_bcd(s->now.tm_sec);
+        s->nvram[1] = to_bcd(s->now.tm_min);
+        if (s->nvram[2] & 0x40) {
+            s->nvram[2] = (to_bcd((s->now.tm_hour % 12)) + 1) | 0x40;
+            if (s->now.tm_hour >= 12) {
+                s->nvram[2] |= 0x20;
+            }
+        } else {
+            s->nvram[2] = to_bcd(s->now.tm_hour);
+        }
+        s->nvram[3] = to_bcd(s->now.tm_wday) + 1;
+        s->nvram[4] = to_bcd(s->now.tm_mday);
+        s->nvram[5] = to_bcd(s->now.tm_mon) + 1;
+        s->nvram[6] = to_bcd(s->now.tm_year - 100);
+        break;
+    case I2C_START_SEND:
+        s->addr_byte = 1;
+        break;
+    default:
+        break;
+    }
+}
+
+static int ds1338_recv(i2c_slave *i2c)
+{
+    DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
+    uint8_t res;
+
+    res  = s->nvram[s->ptr];
+    s->ptr = (s->ptr + 1) & 0xff;
+    return res;
+}
+
+static int ds1338_send(i2c_slave *i2c, uint8_t data)
+{
+    DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c);
+    if (s->addr_byte) {
+        s->ptr = data;
+        s->addr_byte = 0;
+        return 0;
+    }
+    s->nvram[s->ptr - 8] = data;
+    if (data < 8) {
+        qemu_get_timedate(&s->now, s->offset);
+        switch(data) {
+        case 0:
+            /* TODO: Implement CH (stop) bit.  */
+            s->now.tm_sec = from_bcd(data & 0x7f);
+            break;
+        case 1:
+            s->now.tm_min = from_bcd(data & 0x7f);
+            break;
+        case 2:
+            if (data & 0x40) {
+                if (data & 0x20) {
+                    data = from_bcd(data & 0x4f) + 11;
+                } else {
+                    data = from_bcd(data & 0x1f) - 1;
+                }
+            } else {
+                data = from_bcd(data);
+            }
+            s->now.tm_hour = data;
+            break;
+        case 3:
+            s->now.tm_wday = from_bcd(data & 7) - 1;
+            break;
+        case 4:
+            s->now.tm_mday = from_bcd(data & 0x3f);
+            break;
+        case 5:
+            s->now.tm_mon = from_bcd(data & 0x1f) - 1;
+        case 6:
+            s->now.tm_year = from_bcd(data) + 100;
+            break;
+        case 7:
+            /* Control register. Currently ignored.  */
+            break;
+        }
+        s->offset = qemu_timedate_diff(&s->now);
+    }
+    s->ptr = (s->ptr + 1) & 0xff;
+    return 0;
+}
+
+static int ds1338_init(i2c_slave *i2c)
+{
+    return 0;
+}
+
+static I2CSlaveInfo ds1338_info = {
+    .qdev.name = "ds1338",
+    .qdev.size = sizeof(DS1338State),
+    .init = ds1338_init,
+    .event = ds1338_event,
+    .recv = ds1338_recv,
+    .send = ds1338_send,
+};
+
+static void ds1338_register_devices(void)
+{
+    i2c_register_slave(&ds1338_info);
+}
+
+device_init(ds1338_register_devices)