altos: SPI slave code is now per-product

We can't write general purpose SPI slave code as we must eliminate
any latency because the SPI ports have no buffering.

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

5 files changed, 118 insertions, 64 deletions

diff --git a/src/avr/ao_pins.h b/src/avr/ao_pins.h
index 56435f18..88f03829 100644
--- a/src/avr/ao_pins.h
+++ b/src/avr/ao_pins.h
@@ -52,6 +52,13 @@
 	#define SPI_CS_DIR		DDRE
 	#define M25_CS_MASK		(1 << PORTE6)
 	#define M25_MAX_CHIPS		1
+
+	#define SPI_SLAVE_CS_PORT	PORTB
+	#define SPI_SLAVE_CS_PIN	PINB
+	#define SPI_SLAVE_CS_PIN_NO	PINB0
+
+	#define SPI_SLAVE_PIN_0_3	1
+	#define SPI_SLAVE_PIN_2_5	0
 #endif
 
 #endif /* _AO_PINS_H_ */
diff --git a/src/avr/ao_spi_slave.c b/src/avr/ao_spi_slave.c
index e4d866a8..76f574c6 100644
--- a/src/avr/ao_spi_slave.c
+++ b/src/avr/ao_spi_slave.c
@@ -16,18 +16,8 @@
  */
 
 #include "ao.h"
-#include "ao_product.h"
 
-struct ao_companion_command	ao_companion_command;
-
-static const struct ao_companion_setup	ao_telescience_setup = {
-	.board_id 		= AO_idProduct_NUMBER,
-	.board_id_inverse	= ~AO_idProduct_NUMBER,
-	.update_period		= 50,
-	.channels		= AO_LOG_TELESCIENCE_NUM_ADC,
-};
-
-static uint8_t
+uint8_t
 ao_spi_read(uint8_t *buf, uint8_t len)
 {
 	while (len--) {
@@ -39,7 +29,7 @@ ao_spi_read(uint8_t *buf, uint8_t len)
 	return 1;
 }
 
-static void
+void
 ao_spi_write(uint8_t *buf, uint8_t len)
 {
 	while (len--) {
@@ -52,66 +42,38 @@ ao_spi_write(uint8_t *buf, uint8_t len)
 	(void) SPDR;
 }
 
-static uint8_t ao_spi_slave_recv(void)
-{
-	if (!ao_spi_read((uint8_t *) &ao_companion_command,
-			 sizeof (ao_companion_command)))
-		return 0;
-
-	/* Figure out the outbound data */
-	switch (ao_companion_command.command) {
-	case AO_COMPANION_SETUP:
-		ao_spi_write((uint8_t *) &ao_telescience_setup,
-			     sizeof (ao_telescience_setup));
-		break;
-	case AO_COMPANION_FETCH:
-		ao_spi_write((uint8_t *) &ao_adc_ring[ao_adc_ring_prev(ao_adc_head)].adc,
-			     AO_LOG_TELESCIENCE_NUM_ADC * sizeof (uint16_t));
-		break;
-	case AO_COMPANION_NOTIFY:
-		break;
-	default:
-		return 0;
-	}
-
-	ao_log_single_write_data.telescience.tm_tick = ao_companion_command.tick;
-	if (ao_log_single_write_data.telescience.tm_state != ao_companion_command.flight_state) {
-		ao_log_single_write_data.telescience.tm_state = ao_companion_command.flight_state;
-		return 1;
-	}
-	return 0;
-}
-
 static uint8_t ao_spi_slave_running;
 
 ISR(PCINT0_vect)
 {
-	if ((PINB & (1 << PINB0)) == 0) {
+	cli();
+#if SPI_SLAVE_PIN_0_3
+	if ((PINB & (1 << PORTB0)) == 0)
+#endif
+#if SPI_SLAVE_PIN_2_5
+	if ((PINB & (1 << PORTB2)) == 0)
+#endif
+	{
 		if (!ao_spi_slave_running) {
-			uint8_t	changed;
 			ao_spi_slave_running = 1;
-			cli();
-			changed = ao_spi_slave_recv();
-			sei();
-			if (changed && ao_flight_boost <= ao_log_single_write_data.telescience.tm_state) {
-				if (ao_log_single_write_data.telescience.tm_state < ao_flight_landed)
-					ao_log_single_start();
-				else
-					ao_log_single_stop();
-			}
+			ao_spi_slave();
 		}
 	} else {
 		ao_spi_slave_running = 0;
 	}
-}
-
-void ao_spi_slave_debug(void) {
-	printf ("slave running %d\n", ao_spi_slave_running);
+	sei();
 }
 
 void
 ao_spi_slave_init(void)
 {
+	/* We'd like to have a pull-up on SS so that disconnecting the
+	 * TM would cause any SPI transaction to abort. However, when
+	 * I tried that, SPI transactions would spontaneously abort,
+	 * making me assume that we needed a less aggressive pull-up
+	 * than is offered inside the AVR
+	 */
+#if SPI_SLAVE_PIN_0_3
 	PCMSK0 |= (1 << PCINT0);	/* Enable PCINT0 pin change */
 	PCICR |= (1 << PCIE0);		/* Enable pin change interrupt */
 
@@ -121,17 +83,28 @@ ao_spi_slave_init(void)
 		(0 << 1) |		/* SCK, input */
 		(0 << 0));		/* SS, input */
 
-	/* We'd like to have a pull-up on SS so that disconnecting the
-	 * TM would cause any SPI transaction to abort. However, when
-	 * I tried that, SPI transactions would spontaneously abort,
-	 * making me assume that we needed a less aggressive pull-up
-	 * than is offered inside the AVR
-	 */
 	PORTB = ((PORTB & 0xf0) |
 		 (1 << 3) |		/* MISO, output */
 		 (0 << 2) |		/* MOSI, no pull-up */
 		 (0 << 1) |		/* SCK, no pull-up */
 		 (0 << 0));		/* SS, no pull-up */
+#endif
+#if SPI_SLAVE_PIN_2_5
+	PCMSK0 |= (1 << PCINT2);	/* Enable PCINT2 pin change */
+	PCICR |= (1 << PCIE0);		/* Enable pin change interrupt */
+
+	DDRB = ((DDRB & 0xf0) |
+		(0 << 5) |		/* SCK, input */
+		(1 << 4) |		/* MISO, output */
+		(0 << 3) |		/* MOSI, input */
+		(0 << 2));		/* SS, input */
+
+	PORTB = ((PORTB & 0xf0) |
+		 (0 << 5) |		/* SCK, no pull-up */
+		 (1 << 4) |		/* MISO, output */
+		 (0 << 3) |		/* MOSI, no pull-up */
+		 (0 << 2));		/* SS, no pull-up */
+#endif	
 
 	SPCR = (0 << SPIE) |		/* Disable SPI interrupts */
 		(1 << SPE) |		/* Enable SPI */
diff --git a/src/core/ao.h b/src/core/ao.h
index a541d8ac..1d5769cb 100644
--- a/src/core/ao.h
+++ b/src/core/ao.h
@@ -974,12 +974,23 @@ ao_spi_init(void);
  * ao_spi_slave.c
  */
 
+uint8_t
+ao_spi_read(uint8_t *buf, uint8_t len);
+
 void
-ao_spi_slave_debug(void);
+ao_spi_write(uint8_t *buf, uint8_t len);
 
 void
 ao_spi_slave_init(void);
 
+/* This must be defined by the product; it will get called when chip
+ * select goes low, at which point it should use ao_spi_read and
+ * ao_spi_write to deal with the request
+ */
+
+void
+ao_spi_slave(void);
+
 /*
  * ao_telemetry.c
  */
diff --git a/src/drivers/ao_science_slave.c b/src/drivers/ao_science_slave.c
new file mode 100644
index 00000000..e902318f
--- /dev/null
+++ b/src/drivers/ao_science_slave.c
@@ -0,0 +1,62 @@
+/*
+ * Copyright © 2011 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+#include "ao_product.h"
+
+struct ao_companion_command	ao_companion_command;
+
+static const struct ao_companion_setup	ao_telescience_setup = {
+	.board_id 		= AO_idProduct_NUMBER,
+	.board_id_inverse	= ~AO_idProduct_NUMBER,
+	.update_period		= 50,
+	.channels		= AO_LOG_TELESCIENCE_NUM_ADC,
+};
+
+void ao_spi_slave(void)
+{
+	if (!ao_spi_read((uint8_t *) &ao_companion_command,
+			 sizeof (ao_companion_command)))
+		return;
+
+	/* Figure out the outbound data */
+	switch (ao_companion_command.command) {
+	case AO_COMPANION_SETUP:
+		ao_spi_write((uint8_t *) &ao_telescience_setup,
+			     sizeof (ao_telescience_setup));
+		break;
+	case AO_COMPANION_FETCH:
+		ao_spi_write((uint8_t *) &ao_adc_ring[ao_adc_ring_prev(ao_adc_head)].adc,
+			     AO_LOG_TELESCIENCE_NUM_ADC * sizeof (uint16_t));
+		break;
+	case AO_COMPANION_NOTIFY:
+		break;
+	default:
+		return;
+	}
+
+	ao_log_single_write_data.telescience.tm_tick = ao_companion_command.tick;
+	if (ao_log_single_write_data.telescience.tm_state != ao_companion_command.flight_state) {
+		ao_log_single_write_data.telescience.tm_state = ao_companion_command.flight_state;
+		if (ao_flight_boost <= ao_log_single_write_data.telescience.tm_state) {
+			if (ao_log_single_write_data.telescience.tm_state < ao_flight_landed)
+				ao_log_single_start();
+			else
+				ao_log_single_stop();
+		}
+	}
+}
diff --git a/src/telescience-v0.1/Makefile b/src/telescience-v0.1/Makefile
index 28620242..a6797cbe 100644
--- a/src/telescience-v0.1/Makefile
+++ b/src/telescience-v0.1/Makefile
@@ -46,6 +46,7 @@ ALTOS_SRC = \
 	ao_romconfig.c \
 	ao_usb_avr.c \
 	ao_adc_avr.c \
+	ao_science_slave.c \
 	ao_spi_slave.c \
 	ao_log_single.c \
 	ao_log_telescience.c \