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>

4 files changed, 22 insertions, 21 deletions

diff --git a/src/core/ao.h b/src/core/ao.h
index e3161b4c..6c790f69 100644
--- a/src/core/ao.h
+++ b/src/core/ao.h
@@ -638,7 +638,7 @@ ao_monitor_init(void) __reentrant;
 #define AO_READ_AGAIN	(-1)
 
 struct ao_stdio {
-	int	(*pollchar)(void);
+	int	(*_pollchar)(void);	/* Called with interrupts blocked */
 	void	(*putchar)(char c) __reentrant;
 	void	(*flush)(void);
 	uint8_t	echo;
diff --git a/src/core/ao_packet.h b/src/core/ao_packet.h
index 08b184d6..6d121bb9 100644
--- a/src/core/ao_packet.h
+++ b/src/core/ao_packet.h
@@ -63,7 +63,7 @@ void
 ao_packet_putchar(char c) __reentrant;
 
 int
-ao_packet_pollchar(void);
+_ao_packet_pollchar(void);
 
 #if PACKET_HAS_MASTER
 /* ao_packet_master.c */
diff --git a/src/core/ao_serial.h b/src/core/ao_serial.h
index a799bf2c..baf213c0 100644
--- a/src/core/ao_serial.h
+++ b/src/core/ao_serial.h
@@ -32,7 +32,7 @@ char
 ao_serial0_getchar(void);
 
 int
-ao_serial0_pollchar(void);
+_ao_serial0_pollchar(void);
 
 void
 ao_serial0_putchar(char c);
@@ -52,7 +52,7 @@ char
 ao_serial1_getchar(void);
 
 int
-ao_serial1_pollchar(void);
+_ao_serial1_pollchar(void);
 
 void
 ao_serial1_putchar(char c);
@@ -72,7 +72,7 @@ char
 ao_serial2_getchar(void);
 
 int
-ao_serial2_pollchar(void);
+_ao_serial2_pollchar(void);
 
 void
 ao_serial2_putchar(char c);
@@ -92,7 +92,7 @@ char
 ao_serial3_getchar(void);
 
 int
-ao_serial3_pollchar(void);
+_ao_serial3_pollchar(void);
 
 void
 ao_serial3_putchar(char c);
diff --git a/src/core/ao_stdio.c b/src/core/ao_stdio.c
index 1748dfe8..977d74b1 100644
--- a/src/core/ao_stdio.c
+++ b/src/core/ao_stdio.c
@@ -99,20 +99,21 @@ char
 getchar(void) __reentrant
 {
 	int c;
-	ao_arch_critical(
-		int8_t stdio = ao_cur_stdio;
+	int8_t stdio;
 
-		for (;;) {
-			c = ao_stdios[stdio].pollchar();
-			if (c != AO_READ_AGAIN)
-				break;
-			if (++stdio == ao_num_stdios)
-				stdio = 0;
-			if (stdio == ao_cur_stdio)
-				ao_sleep(&ao_stdin_ready);
-		}
-		ao_cur_stdio = stdio;
-		);
+	ao_arch_block_interrupts();
+	stdio = ao_cur_stdio;
+	for (;;) {
+		c = ao_stdios[stdio]._pollchar();
+		if (c != AO_READ_AGAIN)
+			break;
+		if (++stdio == ao_num_stdios)
+			stdio = 0;
+		if (stdio == ao_cur_stdio)
+			ao_sleep(&ao_stdin_ready);
+	}
+	ao_cur_stdio = stdio;
+	ao_arch_release_interrupts();
 	return c;
 }
 
@@ -123,13 +124,13 @@ ao_echo(void)
 }
 
 int8_t
-ao_add_stdio(int (*pollchar)(void),
+ao_add_stdio(int (*_pollchar)(void),
 	     void (*putchar)(char),
 	     void (*flush)(void)) __reentrant
 {
 	if (ao_num_stdios == AO_NUM_STDIOS)
 		ao_panic(AO_PANIC_STDIO);
-	ao_stdios[ao_num_stdios].pollchar = pollchar;
+	ao_stdios[ao_num_stdios]._pollchar = _pollchar;
 	ao_stdios[ao_num_stdios].putchar = putchar;
 	ao_stdios[ao_num_stdios].flush = flush;
 	ao_stdios[ao_num_stdios].echo = 1;