stepper: Introduce and use gpio_out_toggle_noirq()

The gpio_out_toggle() function in the sam3x8e and stm32f1 code was
only valid if it was called with irqs disabled.

Commits 018c5daa and 9c52ad43 enabled the lcd code which called
gpio_out_toggle() with irqs enabled.  This could cause corruption of
the gpio state.

Introduce a gpio_out_toggle_noirq() function that will only be invoked
with irqs disabled, and fix gpio_out_toggle() on sam3x8e and stm32f1
so that it safe to call even if irqs are enabled.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/avr/gpio.c

@@ -63,11 +63,17 @@ fail:
 }
 
 void
-gpio_out_toggle(struct gpio_out g)
+gpio_out_toggle_noirq(struct gpio_out g)
 {
     g.regs->in = g.bit;
 }
 
+void
+gpio_out_toggle(struct gpio_out g)
+{
+    gpio_out_toggle_noirq(g);
+}
+
 void
 gpio_out_write(struct gpio_out g, uint8_t val)
 {

src/avr/gpio.h

@@ -9,6 +9,7 @@ struct gpio_out {
     uint8_t bit : 8;
 };
 struct gpio_out gpio_out_setup(uint8_t pin, uint8_t val);
+void gpio_out_toggle_noirq(struct gpio_out g);
 void gpio_out_toggle(struct gpio_out g);
 void gpio_out_write(struct gpio_out g, uint8_t val);
 

src/generic/gpio.h

@@ -7,6 +7,7 @@ struct gpio_out {
     uint8_t pin;
 };
 struct gpio_out gpio_out_setup(uint8_t pin, uint8_t val);
+void gpio_out_toggle_noirq(struct gpio_out g);
 void gpio_out_toggle(struct gpio_out g);
 void gpio_out_write(struct gpio_out g, uint8_t val);
 

src/gpiocmds.c

@@ -115,7 +115,7 @@ static uint_fast8_t
 soft_pwm_toggle_event(struct timer *timer)
 {
     struct soft_pwm_s *s = container_of(timer, struct soft_pwm_s, timer);
-    gpio_out_toggle(s->pin);
+    gpio_out_toggle_noirq(s->pin);
     s->flags ^= SPF_ON;
     uint32_t waketime = s->timer.waketime;
     if (s->flags & SPF_ON)

src/linux/gpio.h

@@ -7,6 +7,7 @@ struct gpio_out {
     uint32_t pin;
 };
 struct gpio_out gpio_out_setup(uint8_t pin, uint8_t val);
+void gpio_out_toggle_noirq(struct gpio_out g);
 void gpio_out_toggle(struct gpio_out g);
 void gpio_out_write(struct gpio_out g, uint8_t val);
 

src/pru/gpio.c

@@ -104,11 +104,17 @@ fail:
 }
 
 void
-gpio_out_toggle(struct gpio_out g)
+gpio_out_toggle_noirq(struct gpio_out g)
 {
     gpio_out_write(g, !(*g.reg & g.bit));
 }
 
+void
+gpio_out_toggle(struct gpio_out g)
+{
+    gpio_out_toggle_noirq(g);
+}
+
 void
 gpio_out_write(struct gpio_out g, uint8_t val)
 {

src/pru/gpio.h

@@ -9,6 +9,7 @@ struct gpio_out {
     uint32_t bit;
 };
 struct gpio_out gpio_out_setup(uint8_t pin, uint8_t val);
+void gpio_out_toggle_noirq(struct gpio_out g);
 void gpio_out_toggle(struct gpio_out g);
 void gpio_out_write(struct gpio_out g, uint8_t val);
 

src/sam3x8e/gpio.c

@@ -69,12 +69,20 @@ fail:
 }
 
 void
-gpio_out_toggle(struct gpio_out g)
+gpio_out_toggle_noirq(struct gpio_out g)
 {
     Pio *regs = g.regs;
     regs->PIO_ODSR ^= g.bit;
 }
 
+void
+gpio_out_toggle(struct gpio_out g)
+{
+    irqstatus_t flag = irq_save();
+    gpio_out_toggle_noirq(g);
+    irq_restore(flag);
+}
+
 void
 gpio_out_write(struct gpio_out g, uint8_t val)
 {

src/sam3x8e/gpio.h

@@ -10,6 +10,7 @@ struct gpio_out {
     uint32_t bit;
 };
 struct gpio_out gpio_out_setup(uint8_t pin, uint8_t val);
+void gpio_out_toggle_noirq(struct gpio_out g);
 void gpio_out_toggle(struct gpio_out g);
 void gpio_out_write(struct gpio_out g, uint8_t val);
 

src/simulator/gpio.c

@@ -9,6 +9,8 @@
 struct gpio_out gpio_out_setup(uint8_t pin, uint8_t val) {
     return (struct gpio_out){.pin=pin};
 }
+void gpio_out_toggle_noirq(struct gpio_out g) {
+}
 void gpio_out_toggle(struct gpio_out g) {
 }
 void gpio_out_write(struct gpio_out g, uint8_t val) {

src/stepper.c

@@ -88,7 +88,7 @@ stepper_load_next(struct stepper *s, uint32_t min_next_time)
     }
     if (m->flags & MF_DIR) {
         s->position = -s->position + m->count;
-        gpio_out_toggle(s->dir_pin);
+        gpio_out_toggle_noirq(s->dir_pin);
     } else {
         s->position += m->count;
     }
@@ -108,24 +108,24 @@ stepper_event(struct timer *t)
     if (CONFIG_NO_UNSTEP_DELAY) {
         // On slower mcus it is possible to simply step and unstep in
         // the same timer event.
-        gpio_out_toggle(s->step_pin);
+        gpio_out_toggle_noirq(s->step_pin);
         uint16_t count = s->count - 1;
         if (likely(count)) {
             s->count = count;
             s->time.waketime += s->interval;
-            gpio_out_toggle(s->step_pin);
+            gpio_out_toggle_noirq(s->step_pin);
             if (s->flags & SF_HAVE_ADD)
                 s->interval += s->add;
             return SF_RESCHEDULE;
         }
         uint_fast8_t ret = stepper_load_next(s, 0);
-        gpio_out_toggle(s->step_pin);
+        gpio_out_toggle_noirq(s->step_pin);
         return ret;
     }
 
     // On faster mcus, it is necessary to schedule the unstep event
     uint32_t min_next_time = timer_read_time() + UNSTEP_TIME;
-    gpio_out_toggle(s->step_pin);
+    gpio_out_toggle_noirq(s->step_pin);
     s->count--;
     if (likely(s->count & 1))
         // Schedule unstep event

src/stm32f1/gpio.c

@@ -72,11 +72,19 @@ fail:
 }
 
 void
-gpio_out_toggle(struct gpio_out g)
+gpio_out_toggle_noirq(struct gpio_out g)
 {
     LL_GPIO_TogglePin(g.regs, g.bit);
 }
 
+void
+gpio_out_toggle(struct gpio_out g)
+{
+    irqstatus_t flag = irq_save();
+    gpio_out_toggle_noirq(g);
+    irq_restore(flag);
+}
+
 void
 gpio_out_write(struct gpio_out g, uint8_t val)
 {

src/stm32f1/gpio.h

@@ -11,6 +11,7 @@ struct gpio_out {
     uint32_t bit;
 };
 struct gpio_out gpio_out_setup(uint8_t pin, uint8_t val);
+void gpio_out_toggle_noirq(struct gpio_out g);
 void gpio_out_toggle(struct gpio_out g);
 void gpio_out_write(struct gpio_out g, uint8_t val);