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>

2 files changed, 30 insertions, 38 deletions

diff --git a/src/stm/ao_serial_stm.c b/src/stm/ao_serial_stm.c
index ce33f97e..2133c584 100644
--- a/src/stm/ao_serial_stm.c
+++ b/src/stm/ao_serial_stm.c
@@ -59,24 +59,11 @@ ao_usart_isr(struct ao_stm_usart *usart, int stdin)
 	}
 }
 
-char
-ao_usart_getchar(struct ao_stm_usart *usart)
-{
-	char c;
-	ao_arch_block_interrupts();
-	while (ao_fifo_empty(usart->rx_fifo))
-		ao_sleep(&usart->rx_fifo);
-	ao_fifo_remove(usart->rx_fifo, c);
-	ao_arch_release_interrupts();
-	return c;
-}
-
 int
-ao_usart_pollchar(struct ao_stm_usart *usart)
+_ao_usart_pollchar(struct ao_stm_usart *usart)
 {
 	int	c;
 	
-	ao_arch_block_interrupts();
 	if (ao_fifo_empty(usart->rx_fifo))
 		c = AO_READ_AGAIN;
 	else {
@@ -84,10 +71,20 @@ ao_usart_pollchar(struct ao_stm_usart *usart)
 		ao_fifo_remove(usart->rx_fifo,u);
 		c = u;
 	}
-	ao_arch_release_interrupts();
 	return c;
 }
 
+char
+ao_usart_getchar(struct ao_stm_usart *usart)
+{
+	int c;
+	ao_arch_block_interrupts();
+	while ((c = _ao_usart_pollchar(usart)) == AO_READ_AGAIN)
+		ao_sleep(&usart->rx_fifo);
+	ao_arch_release_interrupts();
+	return (char) c;
+}
+
 void
 ao_usart_putchar(struct ao_stm_usart *usart, char c)
 {
@@ -201,9 +198,9 @@ ao_serial1_putchar(char c)
 }
 
 int
-ao_serial1_pollchar(void)
+_ao_serial1_pollchar(void)
 {
-	return ao_usart_pollchar(&ao_stm_usart1);
+	return _ao_usart_pollchar(&ao_stm_usart1);
 }
 
 void
@@ -232,9 +229,9 @@ ao_serial2_putchar(char c)
 }
 
 int
-ao_serial2_pollchar(void)
+_ao_serial2_pollchar(void)
 {
-	return ao_usart_pollchar(&ao_stm_usart2);
+	return _ao_usart_pollchar(&ao_stm_usart2);
 }
 
 void
@@ -263,9 +260,9 @@ ao_serial3_putchar(char c)
 }
 
 int
-ao_serial3_pollchar(void)
+_ao_serial3_pollchar(void)
 {
-	return ao_usart_pollchar(&ao_stm_usart3);
+	return _ao_usart_pollchar(&ao_stm_usart3);
 }
 
 void
@@ -309,7 +306,7 @@ ao_serial_init(void)
 	stm_nvic_set_enable(STM_ISR_USART1_POS);
 	stm_nvic_set_priority(STM_ISR_USART1_POS, 4);
 #if USE_SERIAL_1_STDIN
-	ao_add_stdio(ao_serial1_pollchar,
+	ao_add_stdio(_ao_serial1_pollchar,
 		     ao_serial1_putchar,
 		     NULL);
 #endif
@@ -346,7 +343,7 @@ ao_serial_init(void)
 	stm_nvic_set_enable(STM_ISR_USART2_POS);
 	stm_nvic_set_priority(STM_ISR_USART2_POS, 4);
 #if USE_SERIAL_2_STDIN
-	ao_add_stdio(ao_serial2_pollchar,
+	ao_add_stdio(_ao_serial2_pollchar,
 		     ao_serial2_putchar,
 		     NULL);
 #endif
@@ -390,7 +387,7 @@ ao_serial_init(void)
 	stm_nvic_set_enable(STM_ISR_USART3_POS);
 	stm_nvic_set_priority(STM_ISR_USART3_POS, 4);
 #if USE_SERIAL_3_STDIN
-	ao_add_stdio(ao_serial3_pollchar,
+	ao_add_stdio(_ao_serial3_pollchar,
 		     ao_serial3_putchar,
 		     NULL);
 #endif
diff --git a/src/stm/ao_usb_stm.c b/src/stm/ao_usb_stm.c
index 9379e5cd..dfa58c42 100644
--- a/src/stm/ao_usb_stm.c
+++ b/src/stm/ao_usb_stm.c
@@ -229,10 +229,9 @@ ao_usb_set_stat_tx(int ep, uint32_t stat_tx)
 }
 
 static void
-ao_usb_set_stat_rx(int ep, uint32_t stat_rx) {
+_ao_usb_set_stat_rx(int ep, uint32_t stat_rx) {
 	uint32_t	epr_write, epr_old;
 
-	ao_arch_block_interrupts();
 	epr_write = epr_old = stm_usb.epr[ep];
 	epr_write &= STM_USB_EPR_PRESERVE_MASK;
 	epr_write |= STM_USB_EPR_INVARIANT;
@@ -240,6 +239,12 @@ ao_usb_set_stat_rx(int ep, uint32_t stat_rx) {
 			      STM_USB_EPR_STAT_RX_MASK << STM_USB_EPR_STAT_RX,
 			      stat_rx << STM_USB_EPR_STAT_RX);
 	stm_usb.epr[ep] = epr_write;
+}
+
+static void
+ao_usb_set_stat_rx(int ep, uint32_t stat_rx) {
+	ao_arch_block_interrupts();
+	_ao_usb_set_stat_rx(ep, stat_rx);
 	ao_arch_release_interrupts();
 }
 
@@ -870,10 +875,10 @@ _ao_usb_out_recv(void)
 	ao_usb_rx_pos = 0;
 
 	/* ACK the packet */
-	ao_usb_set_stat_rx(AO_USB_OUT_EPR, STM_USB_EPR_STAT_RX_VALID);
+	_ao_usb_set_stat_rx(AO_USB_OUT_EPR, STM_USB_EPR_STAT_RX_VALID);
 }
 
-static int
+int
 _ao_usb_pollchar(void)
 {
 	uint8_t c;
@@ -896,16 +901,6 @@ _ao_usb_pollchar(void)
 	return c;
 }
 
-int
-ao_usb_pollchar(void)
-{
-	int	c;
-	ao_arch_block_interrupts();
-	c = _ao_usb_pollchar();
-	ao_arch_release_interrupts();
-	return c;
-}
-
 char
 ao_usb_getchar(void)
 {