Apple2 first cut

Rules.mk

@@ -15,6 +15,7 @@ FLAGS += -Wstrict-prototypes -Wredundant-decls -Wnested-externs
 FLAGS += -fno-common -fno-exceptions -fno-strict-aliasing
 FLAGS += -mlittle-endian -mthumb -mfloat-abi=soft
 FLAGS += -Wno-unused-value -ffunction-sections
+FLAGS += -DAPPLE2=1
 
 ## STM32F105
 ifeq ($(mcu),stm32f105)

src/gotek/board.c

@@ -219,10 +219,12 @@ void board_init(void)
 
         if (mcu_package == MCU_QFN32) {
 
+#if !defined(APPLE2)
             /* The sole QFN32 board is a KC30 Rev 1 design. */
             has_kc30_header = 1;
 
             pa_skip &= ~(1<<10); /* PA10 is not used as serial rx */
+#endif
             pb_skip |= 1<<1; /* PB1 is a floppy input (WGATE) */
 
         } else {

src/gotek/floppy.c

@@ -14,8 +14,15 @@
 
 /* Input pins: DIR=PB0, STEP=PA1, SELA=PA0, SELB=PA3, WGATE=PB9, SIDE=PB4, 
  *             MOTOR=PA15/PB15 */
+#if defined(APPLE2)
+#define pin_pha0    6 /* PA6 */
+#define pin_pha1   15 /* PA15 */
+#define pin_pha2    0 /* PB0 */
+#define pin_pha3    1 /* PA1 */
+#else
 #define pin_dir     0 /* PB0 */
 #define pin_step    1 /* PA1 */
+#endif
 #define pin_sel0    0 /* PA0 */
 #define pin_sel1    3 /* PA3 */
 static uint8_t pin_wgate = 9; /* PB9 */
@@ -51,7 +58,12 @@ void IRQ_6(void) __attribute__((alias("IRQ_SELA_changed"))); /* EXTI0 */
 void IRQ_7(void) __attribute__((alias("IRQ_WGATE_rotary"))); /* EXTI1 */
 void IRQ_10(void) __attribute__((alias("IRQ_SIDE_changed"))); /* EXTI4 */
 void IRQ_23(void) __attribute__((alias("IRQ_WGATE_rotary"))); /* EXTI9_5 */
+#if defined(APPLE2)
+static struct timer step_timer;
+static void POLL_step(void *unused);
+#else
 void IRQ_28(void) __attribute__((alias("IRQ_STEP_changed"))); /* TMR2 */
+#endif
 void IRQ_40(void) __attribute__((alias("IRQ_MOTOR_CHGRST_rotary"))); /* EXTI15_10 */
 #define MOTOR_CHGRST_IRQ 40
 static const struct exti_irq exti_irqs[] = {
@@ -80,6 +92,7 @@ static volatile uint32_t *p_dma_rd_active;
 
 bool_t floppy_ribbon_is_reversed(void)
 {
+#if !defined(APPLE2)
     time_t t_start = time_now();
 
     /* If ribbon is reversed then most/all inputs are grounded. 
@@ -91,6 +104,7 @@ bool_t floppy_ribbon_is_reversed(void)
         if (time_since(t_start) > time_ms(1000))
             return TRUE;
     }
+#endif
 
     return FALSE;
 }
@@ -111,7 +125,9 @@ static void board_floppy_init(void)
     gpio->crl = (gpio->crl & ~(0xfu<<((pin)<<2)))       \
         | (((mode)&0xfu)<<((pin)<<2))
 
+#if !defined(APPLE2)
     gpio_configure_pin(gpioa, pin_step, GPI_bus);
+#endif
     gpio_configure_pin(gpio_data, pin_wdata, GPI_bus);
     gpio_configure_pin(gpio_data, pin_rdata, GPO_bus);
 
@@ -122,8 +138,10 @@ static void board_floppy_init(void)
         | (((mode)&0x3u)<<((pin)<<1));
 #define afio syscfg
 
+#if !defined(APPLE2)
     gpio_set_af(gpioa, pin_step, 1);
     gpio_configure_pin(gpioa, pin_step, AFI(PUPD_none));
+#endif
 
     gpio_set_af(gpio_data, pin_wdata, 1);
     gpio_configure_pin(gpio_data, pin_wdata, AFI(PUPD_none));
@@ -149,7 +167,16 @@ static void board_floppy_init(void)
         pin_wgate = 1; /* PB1 */
     }
 
+#if defined(APPLE2)
+    gpio_configure_pin(gpioa, pin_pha0,  GPI_bus);
+    gpio_configure_pin(gpioa, pin_pha1,  GPI_bus);
+    gpio_configure_pin(gpiob, pin_pha2,  GPI_bus);
+    gpio_configure_pin(gpioa, pin_pha3,  GPI_bus);
+    timer_init(&step_timer, POLL_step, NULL);
+    timer_set(&step_timer, time_now());
+#else
     gpio_configure_pin(gpiob, pin_dir,   GPI_bus);
+#endif
     gpio_configure_pin(gpioa, pin_sel0,  GPI_bus);
     gpio_configure_pin(gpiob, pin_wgate, GPI_bus);
     gpio_configure_pin(gpiob, pin_side,  GPI_bus);
@@ -275,6 +302,76 @@ static void update_SELA_irq(bool_t amiga_hd_id)
 #undef OFF
 }
 
+#if defined(APPLE2)
+
+static void POLL_step(void *unused)
+{
+    static unsigned int _pha;
+
+    struct drive *drv = &drive;
+    uint16_t idr_a, idr_b;
+    unsigned int pha;
+
+    /* Latch inputs. */
+    idr_a = gpioa->idr;
+    idr_b = gpiob->idr;
+
+    /* Bail if drive not selected. */
+    if (idr_a & m(pin_sel0)) {
+        _pha = 0;
+        goto out;
+    }
+
+    /* Debounce the phase signals. */
+    pha = _pha;
+    _pha = ((idr_a >> pin_pha0) & 1)
+        | ((idr_a >> (pin_pha1-1)) & 2)
+        | ((idr_b << (2-pin_pha2)) & 4)
+        | ((idr_a << (3-pin_pha3)) & 8);
+    pha &= _pha;
+
+    /* Do nothing while we're mid-step. */
+    if (drv->step.state & STEP_active)
+        goto out;
+
+    /* Rotate the phase bitmap so that the current phase is at bit 0. Note 
+     * that the current phase is directly related to the current cylinder. */
+    pha = ((pha | (pha << 4)) >> (drv->cyl & 3)) & 0xf;
+
+    /* Conditions to action a head step:
+     *  (1) Only one phase is asserted;
+     *  (2) That phase is adjacent to the current phase;
+     *  (3) We haven't hit a cylinder hard limit. */
+    switch (pha) {
+    case m(1): /* Phase +1 only */
+        if (drv->cyl == ff_cfg.max_cyl)
+            goto out;
+        drv->step.inward = TRUE;
+        break;
+    case m(3): /* Phase -1 only */
+        if (drv->cyl == 0)
+            goto out;
+        drv->step.inward = FALSE;
+        break;
+    default:
+        goto out;
+    }
+
+    /* Action a head step. */
+    if (dma_rd != NULL)
+        rdata_stop();
+    if (dma_wr != NULL)
+        wdata_stop();
+    drv->step.start = time_now();
+    drv->step.state = STEP_started;
+    IRQx_set_pending(FLOPPY_SOFTIRQ);
+
+out:
+    timer_set(&step_timer, step_timer.deadline + time_ms(1));
+}
+
+#else
+
 static bool_t drive_is_writing(void)
 {
     if (!dma_wr)
@@ -335,6 +432,8 @@ static void IRQ_STEP_changed(void)
     IRQx_set_pending(FLOPPY_SOFTIRQ);
 }
 
+#endif
+
 static void IRQ_SIDE_changed(void)
 {
     stk_time_t t = stk_now();