altos: SPI radio - use 1->0 for 'done' and 0->1 for 'ready'

This changes how the SPI radio protocol uses the interrupt
line. Instead of a pulse indicating operation done, this now uses a 0
value for done and a 1 value for ready. The key distinction is that
the master can tell when the slave is waiting for the next command
instead of hoping that it got done 'soon enough'.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 41 insertions, 49 deletions

diff --git a/src/drivers/ao_radio_slave.c b/src/drivers/ao_radio_slave.c
index ab23894f..9a01bbfa 100644
--- a/src/drivers/ao_radio_slave.c
+++ b/src/drivers/ao_radio_slave.c
@@ -23,54 +23,69 @@ static __xdata struct ao_radio_spi_reply ao_radio_spi_reply;
 
 static __xdata struct ao_radio_spi_request ao_radio_spi_request;
 
-static __xdata uint8_t	ao_radio_spi_recv_request;
-static __xdata uint8_t	ao_radio_spi_recv_len;
-static __xdata uint16_t	ao_radio_spi_recv_timeout;
+static __xdata uint8_t	slave_state;
 
 static void
-ao_radio_slave_signal(void)
+ao_radio_slave_low(void)
 {
+	uint16_t	i;
+
+	if (slave_state != 1)
+		ao_panic(1);
+	ao_led_toggle(AO_LED_GREEN);
 	ao_gpio_set(AO_RADIO_SLAVE_INT_PORT, AO_RADIO_SLAVE_INT_BIT, AO_RADIO_SLAVE_INT_PIN, 0);
-	ao_arch_nop();
-	ao_arch_nop();
-	ao_arch_nop();
+	for (i = 0; i < 1000; i++)
+		ao_arch_nop();
+	slave_state = 0;
+}
+
+static void
+ao_radio_slave_high(void)
+{
+	if (slave_state != 0)
+		ao_panic(2);
+	ao_led_toggle(AO_LED_RED);
 	ao_gpio_set(AO_RADIO_SLAVE_INT_PORT, AO_RADIO_SLAVE_INT_BIT, AO_RADIO_SLAVE_INT_PIN, 1);
+	slave_state = 1;
 }
 
 static void
 ao_radio_slave_spi(void)
 {
-	uint8_t	need_signal = 0;
-
 	ao_spi_get_slave(AO_RADIO_SLAVE_BUS);
 	for (;;) {
 		ao_spi_recv(&ao_radio_spi_request,
 			    (2 << 13) | sizeof (ao_radio_spi_request),
 			    AO_RADIO_SLAVE_BUS);
-		if (need_signal) {
-			ao_radio_slave_signal();
-			need_signal = 0;
-		}
+		ao_radio_slave_high();
 		ao_spi_recv_wait();
 		switch (ao_radio_spi_request.request) {
 		case AO_RADIO_SPI_RECV:
-		case AO_RADIO_SPI_CMAC_RECV:
+
+			/* XXX monitor CS to interrupt the receive */
+
 			ao_config.radio_setting = ao_radio_spi_request.setting;
-			ao_radio_spi_recv_request = ao_radio_spi_request.request;
-			ao_radio_spi_recv_len = ao_radio_spi_request.recv_len;
-			ao_radio_spi_recv_timeout = ao_radio_spi_request.timeout;
-			ao_wakeup(&ao_radio_spi_recv_len);
+			ao_radio_spi_reply.status = ao_radio_recv(&ao_radio_spi_reply.payload,
+								  ao_radio_spi_request.recv_len);
+			ao_radio_spi_reply.rssi = 0;
+			ao_spi_send(&ao_radio_spi_reply,
+				    AO_RADIO_SPI_REPLY_HEADER_LEN + ao_radio_spi_request.recv_len,
+				    AO_RADIO_SLAVE_BUS);
+			ao_radio_slave_low();
+			ao_spi_send_wait();
 			continue;
-		case AO_RADIO_SPI_RECV_FETCH:
+		case AO_RADIO_SPI_CMAC_RECV:
+			ao_config.radio_setting = ao_radio_spi_request.setting;
+			ao_radio_spi_reply.status = ao_radio_cmac_recv(&ao_radio_spi_reply.payload,
+								       ao_radio_spi_request.recv_len,
+								       ao_radio_spi_request.timeout);
+			ao_radio_spi_reply.rssi = ao_radio_cmac_rssi;
 			ao_spi_send(&ao_radio_spi_reply,
-				    ao_radio_spi_request.recv_len,
+				    AO_RADIO_SPI_REPLY_HEADER_LEN + ao_radio_spi_request.recv_len,
 				    AO_RADIO_SLAVE_BUS);
-			ao_radio_slave_signal();
+			ao_radio_slave_low();
 			ao_spi_send_wait();
 			continue;
-		case AO_RADIO_SPI_RECV_ABORT:
-			ao_radio_recv_abort();
-			break;
 		case AO_RADIO_SPI_SEND:
 			ao_config.radio_setting = ao_radio_spi_request.setting;
 			ao_radio_send(&ao_radio_spi_request.payload,
@@ -96,38 +111,15 @@ ao_radio_slave_spi(void)
 			ao_radio_test(0);
 			break;
 		}
-		need_signal = 1;
-	}
-}
-
-static void
-ao_radio_slave_recv(void)
-{
-	uint8_t	len;
-	for (;;) {
-		while (!ao_radio_spi_recv_len)
-			ao_sleep(&ao_radio_spi_recv_len);
-		len = ao_radio_spi_recv_len;
-		ao_radio_spi_recv_len = 0;
-		if (ao_radio_spi_recv_request == AO_RADIO_SPI_RECV) {
-			ao_radio_spi_reply.status = ao_radio_recv(&ao_radio_spi_reply.payload, len);
-			ao_radio_spi_reply.rssi = 0;
-		} else {
-			ao_radio_spi_reply.status = ao_radio_cmac_recv(&ao_radio_spi_reply.payload, len,
-								       ao_radio_spi_recv_timeout);
-			ao_radio_spi_reply.rssi = ao_radio_cmac_rssi;
-		}
-		ao_radio_slave_signal();
+		ao_radio_slave_low();
 	}
 }
 
 static __xdata struct ao_task ao_radio_slave_spi_task;
-static __xdata struct ao_task ao_radio_slave_recv_task;
 
 void
 ao_radio_slave_init(void)
 {
 	ao_add_task(&ao_radio_slave_spi_task, ao_radio_slave_spi, "radio_spi");
-	ao_add_task(&ao_radio_slave_recv_task, ao_radio_slave_recv, "radio_recv");
-	ao_enable_output(AO_RADIO_SLAVE_INT_PORT, AO_RADIO_SLAVE_INT_BIT, AO_RADIO_SLAVE_INT_PIN, 1);
+	ao_enable_output(AO_RADIO_SLAVE_INT_PORT, AO_RADIO_SLAVE_INT_BIT, AO_RADIO_SLAVE_INT_PIN, 0);
 }