This is to ensure that a device reset always returns the ESCC to a known state.
Note that this is currently redundant with the same code in escc_reset_chn()
but that will change shortly.
Signed-off-by: Mark Cave-Ayland <mark.cave-ayl...@ilande.co.uk>
---
hw/char/escc.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/hw/char/escc.c b/hw/char/escc.c
index c87ecd59d8..b0d3b92dc1 100644
--- a/hw/char/escc.c
+++ b/hw/char/escc.c
@@ -300,9 +300,24 @@ static void escc_reset_chn(ESCCChannelState *s)
static void escc_reset(DeviceState *d)
{
ESCCState *s = ESCC(d);
+ int i, j;
- escc_reset_chn(&s->chn[0]);
- escc_reset_chn(&s->chn[1]);
+ for (i = 0; i < 2; i++) {
+ ESCCChannelState *cs = &s->chn[i];
+
+ /*
+ * According to the ESCC datasheet "Miscellaneous Questions" section
+ * on page 384, the values of the ESCC registers are not guaranteed on
+ * power-on until an explicit hardware or software reset has been
+ * issued. For now we zero the registers so that a device reset always
+ * returns the emulated device to a fixed state.
+ */
+ for (j = 0; j < ESCC_SERIAL_REGS; j++) {
+ cs->rregs[j] = 0;
+ cs->wregs[j] = 0;
+ }
+ escc_reset_chn(cs);
+ }
}
static inline void set_rxint(ESCCChannelState *s)
--
2.20.1
