From f3dc025a764ca6a2c44fb514ccaf22e6210f769d Mon Sep 17 00:00:00 2001
From: Keith Packard <keithp@keithp.com>
Date: Sun, 24 Mar 2013 15:00:20 -0700
Subject: altos: Do not release interrupts from any pollchar function

getchar relies on interrupts being blocked across the pollchar calls
and into the sleep call or it may go to sleep with data pending.

This prefixes all pollchar functions with _ to indicate that they are
to be called with interrupts blocked and eliminates all interrupt
manipulation calls from within the pollchar functions.

Signed-off-by: Keith Packard <keithp@keithp.com>
---
 src/drivers/ao_btm.c           | 52 +++++++++++++++++++++++++++---------------
 src/drivers/ao_packet.c        |  6 ++---
 src/drivers/ao_packet_master.c |  7 +++++-
 src/drivers/ao_packet_slave.c  |  2 +-
 4 files changed, 42 insertions(+), 25 deletions(-)

(limited to 'src/drivers')

diff --git a/src/drivers/ao_btm.c b/src/drivers/ao_btm.c
index c862200a..de1f31a3 100644
--- a/src/drivers/ao_btm.c
+++ b/src/drivers/ao_btm.c
@@ -19,9 +19,10 @@
 
 #ifndef ao_serial_btm_getchar
 #define ao_serial_btm_putchar	ao_serial1_putchar
-#define ao_serial_btm_pollchar	ao_serial1_pollchar
+#define _ao_serial_btm_pollchar	_ao_serial1_pollchar
 #define ao_serial_btm_set_speed ao_serial1_set_speed
 #define ao_serial_btm_drain	ao_serial1_drain
+#define ao_serial_btm_rx_fifo	ao_serial1_rx_fifo
 #endif
 
 int8_t			ao_btm_stdio;
@@ -111,6 +112,30 @@ __code struct ao_cmds ao_btm_cmds[] = {
 #define AO_BTM_MAX_REPLY	16
 __xdata char		ao_btm_reply[AO_BTM_MAX_REPLY];
 
+/*
+ * Read one bluetooth character.
+ * Returns AO_READ_AGAIN if no character arrives within 10ms
+ */
+
+static int
+ao_btm_getchar(void)
+{
+	int	c;
+
+	ao_arch_block_interrupts();
+	while ((c = _ao_serial_btm_pollchar()) == AO_READ_AGAIN) {
+		ao_alarm(AO_MS_TO_TICKS(10));
+		c = ao_sleep(&ao_serial_btm_rx_fifo);
+		ao_clear_alarm();
+		if (c) {
+			c = AO_READ_AGAIN;
+			break;
+		}
+	}
+	ao_arch_release_interrupts();
+	return c;
+}
+
 /*
  * Read a line of data from the serial port, truncating
  * it after a few characters.
@@ -122,24 +147,13 @@ ao_btm_get_line(void)
 	uint8_t ao_btm_reply_len = 0;
 	int c;
 
-	for (;;) {
-
-		while ((c = ao_serial_btm_pollchar()) != AO_READ_AGAIN) {
-			ao_btm_log_in_char(c);
-			if (ao_btm_reply_len < sizeof (ao_btm_reply))
-				ao_btm_reply[ao_btm_reply_len++] = c;
-			if (c == '\r' || c == '\n')
-				goto done;
-		}
-		for (c = 0; c < 10; c++) {
-			ao_delay(AO_MS_TO_TICKS(10));
-			if (!ao_fifo_empty(ao_serial1_rx_fifo))
-				break;
-		}
-		if (c == 10)
-			goto done;
+	while ((c = ao_btm_getchar()) != AO_READ_AGAIN) {
+		ao_btm_log_in_char(c);
+		if (ao_btm_reply_len < sizeof (ao_btm_reply))
+			ao_btm_reply[ao_btm_reply_len++] = c;
+		if (c == '\r' || c == '\n')
+			break;
 	}
-done:
 	for (c = ao_btm_reply_len; c < sizeof (ao_btm_reply);)
 		ao_btm_reply[c++] = '\0';
 	return ao_btm_reply_len;
@@ -279,7 +293,7 @@ ao_btm(void)
 	/* Turn off status reporting */
 	ao_btm_cmd("ATQ1\r");
 
-	ao_btm_stdio = ao_add_stdio(ao_serial_btm_pollchar,
+	ao_btm_stdio = ao_add_stdio(_ao_serial_btm_pollchar,
 				    ao_serial_btm_putchar,
 				    NULL);
 	ao_btm_echo(0);
diff --git a/src/drivers/ao_packet.c b/src/drivers/ao_packet.c
index 91319923..5a507478 100644
--- a/src/drivers/ao_packet.c
+++ b/src/drivers/ao_packet.c
@@ -169,12 +169,10 @@ ao_packet_putchar(char c) __reentrant
 		tx_data[ao_packet_tx_used++] = c;
 }
 
+/* May be called with interrupts blocked */
 int
-ao_packet_pollchar(void)
+_ao_packet_pollchar(void)
 {
-	/* No need to block interrupts, all variables here
-	 * are only manipulated in task context
-	 */
 	if (!ao_packet_enable)
 		return AO_READ_AGAIN;
 
diff --git a/src/drivers/ao_packet_master.c b/src/drivers/ao_packet_master.c
index 023c788b..4c0dc573 100644
--- a/src/drivers/ao_packet_master.c
+++ b/src/drivers/ao_packet_master.c
@@ -21,7 +21,12 @@ static char
 ao_packet_getchar(void)
 {
 	int c;
-	while ((c = ao_packet_pollchar()) == AO_READ_AGAIN) {
+
+	/* No need to block interrupts in this function as
+	 * all packet variables are only modified from task
+	 * context, not an interrupt handler
+	 */
+	while ((c = _ao_packet_pollchar()) == AO_READ_AGAIN) {
 		if (!ao_packet_enable)
 			break;
 		if (ao_packet_master_sleeping)
diff --git a/src/drivers/ao_packet_slave.c b/src/drivers/ao_packet_slave.c
index e45775cb..e75df0d6 100644
--- a/src/drivers/ao_packet_slave.c
+++ b/src/drivers/ao_packet_slave.c
@@ -59,7 +59,7 @@ ao_packet_slave_stop(void)
 void
 ao_packet_slave_init(uint8_t enable)
 {
-	ao_add_stdio(ao_packet_pollchar,
+	ao_add_stdio(_ao_packet_pollchar,
 		     ao_packet_putchar,
 		     NULL);
 	if (enable)
-- 
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