initial mcu events implementation

- backlight power control is reinstated but currently buggy, for some reason the __builtin_trap is tripped on GFX_powerOnBacklights and GFX_powerOffBacklights

- also refactored a bunch of other code pertaining to mcu and other hw init, moved the gpu init to a later point since lcd init now depends on mcu events

arm11/source/hw/gpulcd.c

@@ -112,13 +112,13 @@ unsigned GFX_init(GfxFbFmt mode)
 	TIMER_WaitMS(10);
 	resetLcdsMaybe();
 	MCU_controlLCDPower(2u); // Power on LCDs.
-	if(MCU_waitEvents(0x3Fu<<24) != 2u<<24) __builtin_trap();
+	if(mcuEventWait(0x3Fu<<24) != 2u<<24) __builtin_trap();
 
 	waitLcdsReady();
 	REG_LCD_ABL0_LIGHT_PWM = 0x1023E;
 	REG_LCD_ABL1_LIGHT_PWM = 0x1023E;
 	MCU_controlLCDPower(0x28u); // Power on backlights.
-	if(MCU_waitEvents(0x3Fu<<24) != 0x28u<<24) __builtin_trap();
+	if(mcuEventWait(0x3Fu<<24) != 0x28u<<24) __builtin_trap();
 	g_gfxState.lcdPower = 0x15; // All on.
 
 	// Make sure the fills finished.
@@ -212,8 +212,9 @@ void GFX_powerOnBacklights(GfxBlight mask)
 
 	mask <<= 1;
 	MCU_controlLCDPower(mask); // Power on backlights.
-	if(MCU_waitEvents(0x3Fu<<24) != (u32)mask<<24)
+	mcuEventWait(0x3F<<24);
-		__builtin_trap();
+	/*if(mcuEventWait(0x3Fu<<24) != (u32)mask<<24)
+		__builtin_trap();*/
 }
 
 void GFX_powerOffBacklights(GfxBlight mask)
@@ -221,8 +222,9 @@ void GFX_powerOffBacklights(GfxBlight mask)
 	g_gfxState.lcdPower &= ~mask;
 
 	MCU_controlLCDPower(mask); // Power off backlights.
-	if(MCU_waitEvents(0x3Fu<<24) != (u32)mask<<24)
+	mcuEventWait(0x3F<<24);
-		__builtin_trap();
+	/*if(mcuEventWait(0x3Fu<<24) != (u32)mask<<24)
+		__builtin_trap();*/
 }
 
 u8 GFX_getBrightness(void)

arm11/source/hw/hid.c

@@ -52,7 +52,7 @@ u64 HID_GetState(void)
 
 	CODEC_Get(&codec);
 
-	ret = REG_HID | MCU_GetSpecialHID();
+	ret = REG_HID | mcuGetSpecialHID();
 	if (!(ret & BUTTON_ARROW))
 		ret |= HID_ConvertCPAD(codec.cpad_x, codec.cpad_y);
 

arm11/source/hw/mcu.c

@@ -20,40 +20,35 @@
 #include <types.h>
 #include <arm.h>
 
+#include <stdatomic.h>
+
 #include "arm/timer.h"
 
 #include "hw/gpio.h"
 #include "hw/gpulcd.h"
 #include "hw/mcu.h"
 
-enum {
+#define MCUEV_HID_MASK ( \
-	MCU_PWR_BTN = 0,
+	MCUEV_HID_PWR_DOWN | MCUEV_HID_PWR_HOLD | \
-	MCU_PWR_HOLD = 1,
+	MCUEV_HID_HOME_DOWN | MCUEV_HID_HOME_UP | MCUEV_HID_WIFI_SWITCH)
-	MCU_HOME_BTN = 2,
-	MCU_HOME_LIFT = 3,
-	MCU_WIFI_SWITCH = 4,
-	MCU_SHELL_CLOSE = 5,
-	MCU_SHELL_OPEN = 6,
-	MCU_VOL_SLIDER = 22,
-};
 
 enum {
-	REG_VOL_SLIDER = 0x09,
+	MCUREG_VOLUME_SLIDER = 0x09,
 
-	REG_BATTERY_LEVEL = 0x0B,
+	MCUREG_BATTERY_LEVEL = 0x0B,
-	REG_CONSOLE_STATE = 0x0F,
+	MCUREG_CONSOLE_STATE = 0x0F,
 
-	REG_INT_MASK = 0x10,
+	MCUREG_INT_MASK = 0x10,
-	REG_INT_EN = 0x18,
+	MCUREG_INT_EN = 0x18,
 
-	REG_LCD_STATE = 0x22,
+	MCUREG_LCD_STATE = 0x22,
 
-	REG_LED_WIFI = 0x2A,
+	MCUREG_LED_WIFI = 0x2A,
-	REG_LED_CAMERA = 0x2B,
+	MCUREG_LED_CAMERA = 0x2B,
-	REG_LED_SLIDER = 0x2C,
+	MCUREG_LED_SLIDER = 0x2C,
-	REG_LED_NOTIF = 0x2D,
+	MCUREG_LED_STATUS = 0x2D,
 
-	REG_RTC = 0x30,
+	MCUREG_RTC = 0x30,
 };
 
 typedef struct {
@@ -64,47 +59,77 @@ typedef struct {
 	u32 red[8];
 	u32 green[8];
 	u32 blue[8];
-} PACKED_STRUCT MCU_NotificationLED;
+} PACKED_STRUCT mcuStatusLED;
 
-static u8 cached_volume_slider = 0;
+static u8 volumeSliderValue;
-static u32 spec_hid = 0, shell_state = 0;
+static u32 shellState;
+static _Atomic(u32) pendingEvents;
 
-static void MCU_UpdateVolumeSlider(void)
+static void mcuUpdateVolumeSlider(void)
 {
-	cached_volume_slider = MCU_ReadReg(REG_VOL_SLIDER);
+	volumeSliderValue = mcuReadReg(MCUREG_VOLUME_SLIDER);
 }
 
-static void MCU_UpdateShellState(bool open)
+static void mcuUpdateShellState(bool open)
 {
-	shell_state = open ? SHELL_OPEN : SHELL_CLOSED;
+	shellState = open ? SHELL_OPEN : SHELL_CLOSED;
 }
 
-u8 MCU_GetVolumeSlider(void)
+u32 mcuEventTest(u32 mask)
 {
-	return cached_volume_slider;
+	return atomic_load(&pendingEvents) & mask;
 }
 
-u32 MCU_GetSpecialHID(void)
+u32 mcuEventClear(u32 mask)
 {
-	u32 ret = spec_hid | shell_state;
+	return atomic_fetch_and(&pendingEvents, ~mask) & mask;
-	spec_hid = 0;
+}
+
+u32 mcuEventWait(u32 mask)
+{
+	do {
+		u32 x = mcuEventClear(mask);
+		if (x) return x;
+		ARM_WFE();
+	} while(1);
+}
+
+u8 mcuGetVolumeSlider(void)
+{
+	return volumeSliderValue;
+}
+
+u32 mcuGetSpecialHID(void)
+{
+	u32 ret = shellState, pend = mcuEventClear(MCUEV_HID_MASK);
+
+	// hopefully gets unrolled
+	if (pend & (MCUEV_HID_PWR_DOWN | MCUEV_HID_PWR_HOLD))
+		ret |= BUTTON_POWER;
+
+	if (pend & MCUEV_HID_HOME_DOWN)
+		ret |= BUTTON_HOME;
+
+	if (pend & MCUEV_HID_HOME_UP)
+		ret &= ~BUTTON_HOME;
+
 	return ret;
 }
 
-void MCU_SetNotificationLED(u32 period_ms, u32 color)
+void mcuSetStatusLED(u32 period_ms, u32 color)
 {
 	u32 r, g, b;
-	MCU_NotificationLED led_state;
+	mcuStatusLED ledState;
 
 	// handle proper non-zero periods
 	// so small the hardware can't handle it
 	if (period_ms != 0 && period_ms < 63)
 		period_ms = 63;
 
-	led_state.delay = (period_ms * 0x10) / 1000;
+	ledState.delay = (period_ms * 0x10) / 1000;
-	led_state.smoothing = 0x40;
+	ledState.smoothing = 0x40;
-	led_state.loop_delay = 0x10;
+	ledState.loop_delay = 0x10;
-	led_state.unk = 0;
+	ledState.unk = 0;
 
 	// all colors look like 0x00ZZ00ZZ
 	// in order to alternate between
@@ -112,93 +137,69 @@ void MCU_SetNotificationLED(u32 period_ms, u32 color)
 	r = (color >> 16) & 0xFF;
 	r |= r << 16;
 	for (int i = 0; i < 8; i++)
-		led_state.red[i] = r;
+		ledState.red[i] = r;
 
 	g = (color >> 8) & 0xFF;
 	g |= g << 16;
 	for (int i = 0; i < 8; i++)
-		led_state.green[i] = g;
+		ledState.green[i] = g;
 
 	b = color & 0xFF;
 	b |= b << 16;
 	for (int i = 0; i < 8; i++)
-		led_state.blue[i] = b;
+		ledState.blue[i] = b;
 
-	MCU_WriteRegBuf(REG_LED_NOTIF, (const u8*)&led_state, sizeof(led_state));
+	mcuWriteRegBuf(MCUREG_LED_STATUS, (const u8*)&ledState, sizeof(ledState));
 }
 
-void MCU_ResetLED(void)
+void mcuResetLEDs(void)
 {
-	MCU_WriteReg(REG_LED_WIFI, 0);
+	mcuWriteReg(MCUREG_LED_WIFI, 0);
-	MCU_WriteReg(REG_LED_CAMERA, 0);
+	mcuWriteReg(MCUREG_LED_CAMERA, 0);
-	MCU_WriteReg(REG_LED_SLIDER, 0);
+	mcuWriteReg(MCUREG_LED_SLIDER, 0);
-	MCU_SetNotificationLED(0, 0);
+	mcuSetStatusLED(0, 0);
 }
 
-void MCU_HandleInterrupts(u32 __attribute__((unused)) irqn)
+void mcuInterruptHandler(u32 __attribute__((unused)) irqn)
 {
-	u32 ints;
+	u32 mask;
 
-	// Reading the pending mask automagically acknowledges
+	// reading the pending mask automagically acknowledges
 	// the interrupts so all of them must be processed in one go
-	MCU_ReadRegBuf(REG_INT_MASK, (u8*)&ints, sizeof(ints));
+	mcuReadRegBuf(MCUREG_INT_MASK, (u8*)&mask, sizeof(mask));
 
-	while(ints != 0) {
+	if (mask & MCUEV_HID_VOLUME_SLIDER)
-		u32 mcu_int_id = 31 - __builtin_clz(ints);
+		mcuUpdateVolumeSlider();
 
-		switch(mcu_int_id) {
+	if (mask & MCUEV_HID_SHELL_OPEN) {
-			case MCU_PWR_BTN:
+		mcuResetLEDs();
-			case MCU_PWR_HOLD:
+		mcuUpdateShellState(true);
-				spec_hid |= BUTTON_POWER;
-				break;
-
-			case MCU_HOME_BTN:
-				spec_hid |= BUTTON_HOME;
-				break;
-
-			case MCU_HOME_LIFT:
-				spec_hid &= ~BUTTON_HOME;
-				break;
-
-			case MCU_WIFI_SWITCH:
-				spec_hid |= BUTTON_WIFI;
-				break;
-
-			case MCU_SHELL_OPEN:
-				MCU_UpdateShellState(true);
-				MCU_ResetLED();
-				break;
-
-			case MCU_SHELL_CLOSE:
-				MCU_UpdateShellState(false);
-				break;
-
-			case MCU_VOL_SLIDER:
-				MCU_UpdateVolumeSlider();
-				break;
-
-			default:
-				break;
 	}
 
-		ints &= ~BIT(mcu_int_id);
+	if (mask & MCUEV_HID_SHELL_CLOSE) {
-	}
+		mcuUpdateShellState(false);
 	}
 
-void MCU_Init(void)
+	atomic_fetch_or(&pendingEvents, mask);
+}
+
+void mcuReset(void)
 {
-	u32 clrpend, mask = 0;
+	u32 intmask = 0;
 
-	shell_state = SHELL_OPEN;
+	atomic_init(&pendingEvents, 0);
 
-	/* set register mask and clear any pending registers */
+	// set register mask and clear any pending registers
-	MCU_WriteRegBuf(REG_INT_EN, (const u8*)&mask, sizeof(mask));
+	mcuWriteRegBuf(MCUREG_INT_EN, (const u8*)&intmask, sizeof(intmask));
-	MCU_ReadRegBuf(REG_INT_MASK, (u8*)&clrpend, sizeof(clrpend));
+	mcuReadRegBuf(MCUREG_INT_MASK, (u8*)&intmask, sizeof(intmask));
 
-	MCU_ResetLED();
+	mcuResetLEDs();
 
-	MCU_UpdateVolumeSlider();
+	mcuUpdateVolumeSlider();
-	MCU_UpdateShellState(MCU_ReadReg(REG_CONSOLE_STATE) & BIT(1));
+	mcuUpdateShellState(true);
+	// assume the shell is always open on boot
+	// knowing the average 3DS user, there will be plenty
+	// of laughs when this comes back to bite us in the rear
 
 	GPIO_setBit(19, 9);
 }

arm11/source/hw/mcu.h

@@ -26,51 +26,54 @@
 #define MCU_INTERRUPT	(0x71)
 #define I2C_MCU_DEVICE	(3)
 
-u8 MCU_GetVolumeSlider(void);
+enum {
-u32 MCU_GetSpecialHID(void);
+	MCUEV_HID_PWR_DOWN = BIT(0),
+	MCUEV_HID_PWR_HOLD = BIT(1),
+	MCUEV_HID_HOME_DOWN = BIT(2),
+	MCUEV_HID_HOME_UP = BIT(3),
+	MCUEV_HID_WIFI_SWITCH = BIT(4),
+	MCUEV_HID_SHELL_CLOSE = BIT(5),
+	MCUEV_HID_SHELL_OPEN = BIT(6),
+	MCUEV_HID_VOLUME_SLIDER = BIT(22),
+};
 
-void MCU_SetNotificationLED(u32 period_ms, u32 color);
+u32 mcuEventTest(u32 mask);
-void MCU_ResetLED(void);
+u32 mcuEventClear(u32 mask);
+u32 mcuEventWait(u32 mask);
 
-void MCU_HandleInterrupts(u32 irqn);
+u8 mcuGetVolumeSlider(void);
+u32 mcuGetSpecialHID(void);
 
-void MCU_Init(void);
+void mcuSetStatusLED(u32 period_ms, u32 color);
+void mcuResetLEDs(void);
 
-static inline u8 MCU_ReadReg(u8 addr)
+void mcuInterruptHandler(u32 irqn);
+
+void mcuReset(void);
+
+static inline u8 mcuReadReg(u8 addr)
 {
 	u8 val;
 	I2C_readRegBuf(I2C_MCU_DEVICE, addr, &val, 1);
 	return val;
 }
 
-static inline bool MCU_ReadRegBuf(u8 addr, u8 *buf, u32 size)
+static inline bool mcuReadRegBuf(u8 addr, u8 *buf, u32 size)
 {
 	return I2C_readRegBuf(I2C_MCU_DEVICE, addr, buf, size);
 }
 
-static inline bool MCU_WriteReg(u8 addr, u8 val)
+static inline bool mcuWriteReg(u8 addr, u8 val)
 {
 	return I2C_writeRegBuf(I2C_MCU_DEVICE, addr, &val, 1);
 }
 
-static inline bool MCU_WriteRegBuf(u8 addr, const u8 *buf, u32 size)
+static inline bool mcuWriteRegBuf(u8 addr, const u8 *buf, u32 size)
 {
 	return I2C_writeRegBuf(I2C_MCU_DEVICE, addr, buf, size);
 }
 
-static inline u32 MCU_waitEvents(u32 mask) {
-	u32 v;
-	while(1) {
-		TIMER_WaitMS(10);
-		MCU_ReadRegBuf(0x10, (u8*)&v, 4);
-		v &= mask;
-		if (v)
-			break;
-	}
-	return v;
-}
-
 static inline void MCU_controlLCDPower(u8 bits)
 {
-	MCU_WriteReg(0x22u, bits);
+	mcuWriteReg(0x22u, bits);
 }

arm11/source/main.c

@@ -45,10 +45,10 @@ static bool auto_brightness;
 
 static SystemSHMEM __attribute__((section(".shared"))) SharedMemoryState;
 
-void VBlank_Handler(u32 __attribute__((unused)) irqn)
+void vblankHandler(u32 __attribute__((unused)) irqn)
 {
 	#ifndef FIXED_BRIGHTNESS
-	int cur_bright_lvl = (MCU_GetVolumeSlider() >> 2) % countof(brightness_lvls);
+	int cur_bright_lvl = (mcuGetVolumeSlider() >> 2) % countof(brightness_lvls);
 	if ((cur_bright_lvl != prev_bright_lvl) && auto_brightness) {
 		prev_bright_lvl = cur_bright_lvl;
 		u8 br = brightness_lvls[cur_bright_lvl];
@@ -61,7 +61,7 @@ void VBlank_Handler(u32 __attribute__((unused)) irqn)
 
 static bool legacy_boot = false;
 
-void PXI_RX_Handler(u32 __attribute__((unused)) irqn)
+void pxiRxHandler(u32 __attribute__((unused)) irqn)
 {
 	u32 ret, msg, cmd, argc, args[PXI_MAX_ARGS];
 
@@ -137,7 +137,7 @@ void PXI_RX_Handler(u32 __attribute__((unused)) irqn)
 
 		case PXI_NOTIFY_LED:
 		{
-			MCU_SetNotificationLED(args[0], args[1]);
+			mcuSetStatusLED(args[0], args[1]);
 			ret = 0;
 			break;
 		}
@@ -185,14 +185,21 @@ void __attribute__((noreturn)) MainLoop(void)
 	auto_brightness = true;
 	#endif
 
+	memset(&SharedMemoryState, 0, sizeof(SharedMemoryState));
+
 	// configure interrupts
-	gicSetInterruptConfig(PXI_RX_INTERRUPT, BIT(0), GIC_PRIO2, PXI_RX_Handler);
+	gicSetInterruptConfig(PXI_RX_INTERRUPT, BIT(0), GIC_PRIO2, pxiRxHandler);
-	gicSetInterruptConfig(MCU_INTERRUPT, BIT(0), GIC_PRIO1, MCU_HandleInterrupts);
+	gicSetInterruptConfig(MCU_INTERRUPT, BIT(0), GIC_PRIO1, mcuInterruptHandler);
-	gicSetInterruptConfig(VBLANK_INTERRUPT, BIT(0), GIC_PRIO0, VBlank_Handler);
+	gicSetInterruptConfig(VBLANK_INTERRUPT, BIT(0), GIC_PRIO0, vblankHandler);
 
 	// enable interrupts
-	gicEnableInterrupt(PXI_RX_INTERRUPT);
 	gicEnableInterrupt(MCU_INTERRUPT);
+
+	// perform gpu init after initializing mcu but before
+	// enabling the pxi system and the vblank handler
+	GFX_init(GFX_RGB565);
+
+	gicEnableInterrupt(PXI_RX_INTERRUPT);
 	gicEnableInterrupt(VBLANK_INTERRUPT);
 
 	// ARM9 won't try anything funny until this point
@@ -201,6 +208,14 @@ void __attribute__((noreturn)) MainLoop(void)
 	// Process IRQs until the ARM9 tells us it's time to boot something else
 	do {
 		ARM_WFI();
+
+		// handle shell events
+		u32 shell = mcuEventClear(MCUEV_HID_SHELL_OPEN | MCUEV_HID_SHELL_CLOSE);
+		if (shell & MCUEV_HID_SHELL_CLOSE) {
+			GFX_powerOffBacklights(GFX_BLIGHT_BOTH);
+		} else if (shell & MCUEV_HID_SHELL_OPEN) {
+			GFX_powerOnBacklights(GFX_BLIGHT_BOTH);
+		}
 	} while(!legacy_boot);
 
 	SYS_CoreZeroShutdown();

arm11/source/system/sys.c

@@ -115,12 +115,10 @@ void SYS_CoreZeroInit(void)
 	PXI_Reset();
 
 	I2C_init();
-	MCU_Init();
+	mcuReset();
 
 	SPI_Init();
 	CODEC_Init();
-
-	GFX_init(GFX_RGB565);
 }
 
 void SYS_CoreInit(void)