firmware/os/platform/stm32/gpio.c - device/google/contexthub - Git at Google

 /*
  * Copyright (C) 2016 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #include <plat/gpio.h>
 #include <plat/pwr.h>
 #include <gpio.h>
 #include <cpu.h>

 struct StmGpio {
     volatile uint32_t MODER;
     volatile uint32_t OTYPER;
     volatile uint32_t OSPEEDR;
     volatile uint32_t PUPDR;
     volatile uint32_t IDR;
     volatile uint32_t ODR;
     volatile uint32_t BSRR;
     volatile uint32_t LCKR;
     volatile uint32_t AFR[2];
 };

 static const uint32_t mGpioPeriphs[] = {
     PERIPH_AHB1_GPIOA,
     PERIPH_AHB1_GPIOB,
     PERIPH_AHB1_GPIOC,
     PERIPH_AHB1_GPIOD,
     PERIPH_AHB1_GPIOE,
     PERIPH_AHB1_GPIOF,
     PERIPH_AHB1_GPIOG,
     PERIPH_AHB1_GPIOH,
     PERIPH_AHB1_GPIOI,
 };

 static const uint32_t mGpioBases[] = {
     GPIOA_BASE,
     GPIOB_BASE,
     GPIOC_BASE,
     GPIOD_BASE,
     GPIOE_BASE,
     GPIOF_BASE,
     GPIOG_BASE,
     GPIOH_BASE,
     GPIOI_BASE,
 };

 static void gpioSetWithNum(uint32_t gpioNum, bool value);


 struct Gpio* gpioRequest(uint32_t number)
 {
     return (struct Gpio*)(((uintptr_t)number) + GPIO_HANDLE_OFFSET);
 }

 void gpioRelease(struct Gpio* __restrict gpio)
 {
     (void)gpio;
 }

 static enum StmGpioSpeed gpioSpeedFromRequestedSpeed(int32_t requestedSpeed)
 {
     static const enum StmGpioSpeed mStandardSpeeds[] = {
         [-1 - GPIO_SPEED_BEST_POWER  ] = GPIO_SPEED_LOW,
         [-1 - GPIO_SPEED_BEST_SPEED  ] = GPIO_SPEED_HIGH,
         [-1 - GPIO_SPEED_DEFAULT     ] = GPIO_SPEED_MEDIUM,
         [-1 - GPIO_SPEED_1MHZ_PLUS   ] = GPIO_SPEED_LOW,
         [-1 - GPIO_SPEED_3MHZ_PLUS   ] = GPIO_SPEED_LOW,
         [-1 - GPIO_SPEED_5MHZ_PLUS   ] = GPIO_SPEED_MEDIUM,
         [-1 - GPIO_SPEED_10MHZ_PLUS  ] = GPIO_SPEED_MEDIUM,
         [-1 - GPIO_SPEED_15MHZ_PLUS  ] = GPIO_SPEED_MEDIUM,
         [-1 - GPIO_SPEED_20MHZ_PLUS  ] = GPIO_SPEED_MEDIUM,
         [-1 - GPIO_SPEED_30MHZ_PLUS  ] = GPIO_SPEED_FAST,
         [-1 - GPIO_SPEED_50MHZ_PLUS  ] = GPIO_SPEED_FAST,
         [-1 - GPIO_SPEED_100MHZ_PLUS ] = GPIO_SPEED_FAST,
         [-1 - GPIO_SPEED_150MHZ_PLUS ] = GPIO_SPEED_FAST,  //this is not fast enough, but it is all we can do
         [-1 - GPIO_SPEED_150MHZ_PLUS ] = GPIO_SPEED_FAST,  //this is not fast enough, but it is all we can do
     };

     if (requestedSpeed >= 0)
         return requestedSpeed;
     else
         return mStandardSpeeds[-requestedSpeed - 1];
 }

 static void gpioConfigWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output)
 {
     struct StmGpio *block = (struct StmGpio*)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
     const uint32_t shift_1b = gpioNum & GPIO_PIN_MASK;
     const uint32_t shift_2b = (gpioNum & GPIO_PIN_MASK) * 2;
     const uint32_t mask_1b = (1UL << shift_1b);
     const uint32_t mask_2b = (3UL << shift_2b);

     /* unit clock */
     pwrUnitClock(PERIPH_BUS_AHB1, mGpioPeriphs[gpioNum >> GPIO_PORT_SHIFT], true);

     /* speed */
     block->OSPEEDR = (block->OSPEEDR & ~mask_2b) | (((uint32_t)gpioSpeedFromRequestedSpeed(gpioSpeed)) << shift_2b);

     /* pull ups/downs */
     block->PUPDR = (block->PUPDR & ~mask_2b) | (((uint32_t)pull) << shift_2b);
     /* push/pull or open drain */
     if (output == GPIO_OUT_PUSH_PULL)
         block->OTYPER &= ~mask_1b;
     else
         block->OTYPER |= mask_1b;
 }

 static void gpioConfigInputWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull)
 {
     struct StmGpio *block = (struct StmGpio*)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
     const uint32_t shift_2b = (gpioNum & GPIO_PIN_MASK) * 2;
     const uint32_t mask_2b = (3UL << shift_2b);

     gpioConfigWithNum(gpioNum, gpioSpeed, pull, GPIO_OUT_PUSH_PULL);

     /* direction */
     block->MODER = (block->MODER & ~mask_2b) | (((uint32_t)GPIO_MODE_IN) << shift_2b);
 }

 void gpioConfigInput(const struct Gpio* __restrict gpioHandle, int32_t gpioSpeed, enum GpioPullMode pull)
 {
     if (gpioHandle)
         gpioConfigInputWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, gpioSpeed, pull);
 }

 static void gpioConfigOutputWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, bool value)
 {
     struct StmGpio *block = (struct StmGpio*)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
     const uint32_t shift_2b = (gpioNum & GPIO_PIN_MASK) * 2;
     const uint32_t mask_2b = (3UL << shift_2b);

     gpioConfigWithNum(gpioNum, gpioSpeed, pull, output);

     /* set the initial output value */
     gpioSetWithNum(gpioNum, value);

     /* direction */
     block->MODER = (block->MODER & ~mask_2b) | (((uint32_t)GPIO_MODE_OUT) << shift_2b);
 }

 void gpioConfigOutput(const struct Gpio* __restrict gpioHandle, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, bool value)
 {
     if (gpioHandle)
         gpioConfigOutputWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, gpioSpeed, pull, output, value);
 }

 static void gpioConfigAltWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, uint32_t altFunc)
 {
     struct StmGpio *block = (struct StmGpio*)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
     const uint32_t pinNo = gpioNum & GPIO_PIN_MASK;
     const uint32_t regNo = pinNo >> (GPIO_PORT_SHIFT - 1);
     const uint32_t nibbleNo = pinNo & (GPIO_PIN_MASK >> 1);
     const uint32_t shift_2b = pinNo * 2;
     const uint32_t shift_4b = nibbleNo * 4;
     const uint32_t mask_2b = (3UL << shift_2b);
     const uint32_t mask_4b = (15UL << shift_4b);

     gpioConfigWithNum(gpioNum, gpioSpeed, pull, output);

     /* assign function */
     block->AFR[regNo] = (block->AFR[regNo] & ~mask_4b) | (((uint32_t)altFunc) << shift_4b);

     /* direction */
     block->MODER = (block->MODER & ~mask_2b) | (((uint32_t)GPIO_MODE_ALTERNATE) << shift_2b);
 }

 void gpioConfigAlt(const struct Gpio* __restrict gpioHandle, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, uint32_t altFunc)
 {
     if (gpioHandle)
         gpioConfigAltWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, gpioSpeed, pull, output, altFunc);
 }

 static void gpioConfigAnalogWithNum(uint32_t gpioNum)
 {
     struct StmGpio *block = (struct StmGpio*)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
     const uint32_t pinNo = gpioNum & GPIO_PIN_MASK;
     const uint32_t shift_2b = pinNo * 2;
     const uint32_t mask_2b = (3UL << shift_2b);

     gpioConfigWithNum(gpioNum, GPIO_SPEED_LOW, GPIO_PULL_NONE, GPIO_OUT_OPEN_DRAIN);

     /* I/O configuration */
     block->MODER = (block->MODER & ~mask_2b) | (((uint32_t)GPIO_MODE_ANALOG) << shift_2b);
 }

 void gpioConfigAnalog(const struct Gpio* __restrict gpioHandle)
 {
     if (gpioHandle)
         gpioConfigAnalogWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET);
 }

 static void gpioSetWithNum(uint32_t gpioNum, bool value)
 {
     struct StmGpio *block = (struct StmGpio*)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
     const uint32_t shift_1b = gpioNum & GPIO_PIN_MASK;
     const uint32_t mask_set_1b = (1UL << (0  + shift_1b));
     const uint32_t mask_clr_1b = (1UL << (16 + shift_1b));

     block->BSRR = value ? mask_set_1b : mask_clr_1b;
 }

 void gpioSet(const struct Gpio* __restrict gpioHandle, bool value)
 {
     if (gpioHandle)
         gpioSetWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, value);
 }

 static bool gpioGetWithNum(uint32_t gpioNum)
 {
     struct StmGpio *block = (struct StmGpio*)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
     const uint32_t shift_1b = gpioNum & GPIO_PIN_MASK;
     const uint32_t mask_1b = (1UL << shift_1b);

     return !!(block->IDR & mask_1b);
 }

 bool gpioGet(const struct Gpio* __restrict gpioHandle)
 {
     return gpioHandle ? gpioGetWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET) : 0;
 }


 #ifdef DEBUG_UART_PIN

 //this function makes more assumptions than i'd care to list, sorry...
 void gpioBitbangedUartOut(uint32_t chr)
 {
     static const uint32_t bsrrVals[] = {(1 << (DEBUG_UART_PIN & GPIO_PIN_MASK)) << 16, (1 << (DEBUG_UART_PIN & GPIO_PIN_MASK))};
     struct StmGpio *block = (struct StmGpio*)mGpioBases[DEBUG_UART_PIN >> GPIO_PORT_SHIFT];
     uint32_t bits[10], *bitsP = bits, base = (uint32_t)&block->BSRR;
     static bool setup = 0;
     uint64_t state;
     uint32_t i;

     if (!setup) {
         struct Gpio *gpio = gpioRequest(DEBUG_UART_PIN);

         if (!gpio)
             return;

         setup = true;
         gpioConfigOutput(gpio, GPIO_SPEED_HIGH, GPIO_PULL_NONE, GPIO_OUT_PUSH_PULL, true);
     }

     bits[0] = bsrrVals[0];
     for (i = 0; i < 8; i++, chr >>= 1)
         bits[i + 1] = bsrrVals[chr & 1];
     bits[9] = bsrrVals[1];

     #define SENDBIT "ldr %0, [%1], #4   \n\t"   \
    "str %0, [%2]   \n\t"   \
    "nop    \n\t"   \
    "nop    \n\t"   \
    "nop    \n\t"   \
    "nop    \n\t"   \
    "nop    \n\t"   \
    "nop    \n\t"

    state = cpuIntsOff();
    asm volatile(
        SENDBIT
        SENDBIT
        SENDBIT
        SENDBIT
        SENDBIT
        SENDBIT
        SENDBIT
        SENDBIT
        SENDBIT
        SENDBIT
        :"=r"(i), "=r"(bitsP), "=r"(base)
        :"0"(i), "1"(bitsP), "2"(base)
        :"memory","cc"
     );
     cpuIntsRestore(state);
 }


 #endif
	/*
	* Copyright (C) 2016 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#include <plat/gpio.h>
	#include <plat/pwr.h>
	#include <gpio.h>
	#include <cpu.h>

	struct StmGpio {
	volatile uint32_t MODER;
	volatile uint32_t OTYPER;
	volatile uint32_t OSPEEDR;
	volatile uint32_t PUPDR;
	volatile uint32_t IDR;
	volatile uint32_t ODR;
	volatile uint32_t BSRR;
	volatile uint32_t LCKR;
	volatile uint32_t AFR[2];
	};

	static const uint32_t mGpioPeriphs[] = {
	PERIPH_AHB1_GPIOA,
	PERIPH_AHB1_GPIOB,
	PERIPH_AHB1_GPIOC,
	PERIPH_AHB1_GPIOD,
	PERIPH_AHB1_GPIOE,
	PERIPH_AHB1_GPIOF,
	PERIPH_AHB1_GPIOG,
	PERIPH_AHB1_GPIOH,
	PERIPH_AHB1_GPIOI,
	};

	static const uint32_t mGpioBases[] = {
	GPIOA_BASE,
	GPIOB_BASE,
	GPIOC_BASE,
	GPIOD_BASE,
	GPIOE_BASE,
	GPIOF_BASE,
	GPIOG_BASE,
	GPIOH_BASE,
	GPIOI_BASE,
	};

	static void gpioSetWithNum(uint32_t gpioNum, bool value);


	struct Gpio* gpioRequest(uint32_t number)
	{
	return (struct Gpio*)(((uintptr_t)number) + GPIO_HANDLE_OFFSET);
	}

	void gpioRelease(struct Gpio* __restrict gpio)
	{
	(void)gpio;
	}

	static enum StmGpioSpeed gpioSpeedFromRequestedSpeed(int32_t requestedSpeed)
	{
	static const enum StmGpioSpeed mStandardSpeeds[] = {
	[-1 - GPIO_SPEED_BEST_POWER ] = GPIO_SPEED_LOW,
	[-1 - GPIO_SPEED_BEST_SPEED ] = GPIO_SPEED_HIGH,
	[-1 - GPIO_SPEED_DEFAULT ] = GPIO_SPEED_MEDIUM,
	[-1 - GPIO_SPEED_1MHZ_PLUS ] = GPIO_SPEED_LOW,
	[-1 - GPIO_SPEED_3MHZ_PLUS ] = GPIO_SPEED_LOW,
	[-1 - GPIO_SPEED_5MHZ_PLUS ] = GPIO_SPEED_MEDIUM,
	[-1 - GPIO_SPEED_10MHZ_PLUS ] = GPIO_SPEED_MEDIUM,
	[-1 - GPIO_SPEED_15MHZ_PLUS ] = GPIO_SPEED_MEDIUM,
	[-1 - GPIO_SPEED_20MHZ_PLUS ] = GPIO_SPEED_MEDIUM,
	[-1 - GPIO_SPEED_30MHZ_PLUS ] = GPIO_SPEED_FAST,
	[-1 - GPIO_SPEED_50MHZ_PLUS ] = GPIO_SPEED_FAST,
	[-1 - GPIO_SPEED_100MHZ_PLUS ] = GPIO_SPEED_FAST,
	[-1 - GPIO_SPEED_150MHZ_PLUS ] = GPIO_SPEED_FAST, //this is not fast enough, but it is all we can do
	[-1 - GPIO_SPEED_150MHZ_PLUS ] = GPIO_SPEED_FAST, //this is not fast enough, but it is all we can do
	};

	if (requestedSpeed >= 0)
	return requestedSpeed;
	else
	return mStandardSpeeds[-requestedSpeed - 1];
	}

	static void gpioConfigWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output)
	{
	struct StmGpio block = (struct StmGpio)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
	const uint32_t shift_1b = gpioNum & GPIO_PIN_MASK;
	const uint32_t shift_2b = (gpioNum & GPIO_PIN_MASK) * 2;
	const uint32_t mask_1b = (1UL << shift_1b);
	const uint32_t mask_2b = (3UL << shift_2b);

	/* unit clock */
	pwrUnitClock(PERIPH_BUS_AHB1, mGpioPeriphs[gpioNum >> GPIO_PORT_SHIFT], true);

	/* speed */
	block->OSPEEDR = (block->OSPEEDR & ~mask_2b) \| (((uint32_t)gpioSpeedFromRequestedSpeed(gpioSpeed)) << shift_2b);

	/* pull ups/downs */
	block->PUPDR = (block->PUPDR & ~mask_2b) \| (((uint32_t)pull) << shift_2b);
	/* push/pull or open drain */
	if (output == GPIO_OUT_PUSH_PULL)
	block->OTYPER &= ~mask_1b;
	else
	block->OTYPER \|= mask_1b;
	}

	static void gpioConfigInputWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull)
	{
	struct StmGpio block = (struct StmGpio)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
	const uint32_t shift_2b = (gpioNum & GPIO_PIN_MASK) * 2;
	const uint32_t mask_2b = (3UL << shift_2b);

	gpioConfigWithNum(gpioNum, gpioSpeed, pull, GPIO_OUT_PUSH_PULL);

	/* direction */
	block->MODER = (block->MODER & ~mask_2b) \| (((uint32_t)GPIO_MODE_IN) << shift_2b);
	}

	void gpioConfigInput(const struct Gpio* __restrict gpioHandle, int32_t gpioSpeed, enum GpioPullMode pull)
	{
	if (gpioHandle)
	gpioConfigInputWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, gpioSpeed, pull);
	}

	static void gpioConfigOutputWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, bool value)
	{
	struct StmGpio block = (struct StmGpio)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
	const uint32_t shift_2b = (gpioNum & GPIO_PIN_MASK) * 2;
	const uint32_t mask_2b = (3UL << shift_2b);

	gpioConfigWithNum(gpioNum, gpioSpeed, pull, output);

	/* set the initial output value */
	gpioSetWithNum(gpioNum, value);

	/* direction */
	block->MODER = (block->MODER & ~mask_2b) \| (((uint32_t)GPIO_MODE_OUT) << shift_2b);
	}

	void gpioConfigOutput(const struct Gpio* __restrict gpioHandle, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, bool value)
	{
	if (gpioHandle)
	gpioConfigOutputWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, gpioSpeed, pull, output, value);
	}

	static void gpioConfigAltWithNum(uint32_t gpioNum, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, uint32_t altFunc)
	{
	struct StmGpio block = (struct StmGpio)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
	const uint32_t pinNo = gpioNum & GPIO_PIN_MASK;
	const uint32_t regNo = pinNo >> (GPIO_PORT_SHIFT - 1);
	const uint32_t nibbleNo = pinNo & (GPIO_PIN_MASK >> 1);
	const uint32_t shift_2b = pinNo * 2;
	const uint32_t shift_4b = nibbleNo * 4;
	const uint32_t mask_2b = (3UL << shift_2b);
	const uint32_t mask_4b = (15UL << shift_4b);

	gpioConfigWithNum(gpioNum, gpioSpeed, pull, output);

	/* assign function */
	block->AFR[regNo] = (block->AFR[regNo] & ~mask_4b) \| (((uint32_t)altFunc) << shift_4b);

	/* direction */
	block->MODER = (block->MODER & ~mask_2b) \| (((uint32_t)GPIO_MODE_ALTERNATE) << shift_2b);
	}

	void gpioConfigAlt(const struct Gpio* __restrict gpioHandle, int32_t gpioSpeed, enum GpioPullMode pull, enum GpioOpenDrainMode output, uint32_t altFunc)
	{
	if (gpioHandle)
	gpioConfigAltWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, gpioSpeed, pull, output, altFunc);
	}

	static void gpioConfigAnalogWithNum(uint32_t gpioNum)
	{
	struct StmGpio block = (struct StmGpio)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
	const uint32_t pinNo = gpioNum & GPIO_PIN_MASK;
	const uint32_t shift_2b = pinNo * 2;
	const uint32_t mask_2b = (3UL << shift_2b);

	gpioConfigWithNum(gpioNum, GPIO_SPEED_LOW, GPIO_PULL_NONE, GPIO_OUT_OPEN_DRAIN);

	/* I/O configuration */
	block->MODER = (block->MODER & ~mask_2b) \| (((uint32_t)GPIO_MODE_ANALOG) << shift_2b);
	}

	void gpioConfigAnalog(const struct Gpio* __restrict gpioHandle)
	{
	if (gpioHandle)
	gpioConfigAnalogWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET);
	}

	static void gpioSetWithNum(uint32_t gpioNum, bool value)
	{
	struct StmGpio block = (struct StmGpio)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
	const uint32_t shift_1b = gpioNum & GPIO_PIN_MASK;
	const uint32_t mask_set_1b = (1UL << (0 + shift_1b));
	const uint32_t mask_clr_1b = (1UL << (16 + shift_1b));

	block->BSRR = value ? mask_set_1b : mask_clr_1b;
	}

	void gpioSet(const struct Gpio* __restrict gpioHandle, bool value)
	{
	if (gpioHandle)
	gpioSetWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET, value);
	}

	static bool gpioGetWithNum(uint32_t gpioNum)
	{
	struct StmGpio block = (struct StmGpio)mGpioBases[gpioNum >> GPIO_PORT_SHIFT];
	const uint32_t shift_1b = gpioNum & GPIO_PIN_MASK;
	const uint32_t mask_1b = (1UL << shift_1b);

	return !!(block->IDR & mask_1b);
	}

	bool gpioGet(const struct Gpio* __restrict gpioHandle)
	{
	return gpioHandle ? gpioGetWithNum((uint32_t)gpioHandle - GPIO_HANDLE_OFFSET) : 0;
	}


	#ifdef DEBUG_UART_PIN

	//this function makes more assumptions than i'd care to list, sorry...
	void gpioBitbangedUartOut(uint32_t chr)
	{
	static const uint32_t bsrrVals[] = {(1 << (DEBUG_UART_PIN & GPIO_PIN_MASK)) << 16, (1 << (DEBUG_UART_PIN & GPIO_PIN_MASK))};
	struct StmGpio block = (struct StmGpio)mGpioBases[DEBUG_UART_PIN >> GPIO_PORT_SHIFT];
	uint32_t bits[10], *bitsP = bits, base = (uint32_t)&block->BSRR;
	static bool setup = 0;
	uint64_t state;
	uint32_t i;

	if (!setup) {
	struct Gpio *gpio = gpioRequest(DEBUG_UART_PIN);

	if (!gpio)
	return;

	setup = true;
	gpioConfigOutput(gpio, GPIO_SPEED_HIGH, GPIO_PULL_NONE, GPIO_OUT_PUSH_PULL, true);
	}

	bits[0] = bsrrVals[0];
	for (i = 0; i < 8; i++, chr >>= 1)
	bits[i + 1] = bsrrVals[chr & 1];
	bits[9] = bsrrVals[1];

	#define SENDBIT "ldr %0, [%1], #4 \n\t" \
	"str %0, [%2] \n\t" \
	"nop \n\t" \
	"nop \n\t" \
	"nop \n\t" \
	"nop \n\t" \
	"nop \n\t" \
	"nop \n\t"

	state = cpuIntsOff();
	asm volatile(
	SENDBIT
	SENDBIT
	SENDBIT
	SENDBIT
	SENDBIT
	SENDBIT
	SENDBIT
	SENDBIT
	SENDBIT
	SENDBIT
	:"=r"(i), "=r"(bitsP), "=r"(base)
	:"0"(i), "1"(bitsP), "2"(base)
	:"memory","cc"
	);
	cpuIntsRestore(state);
	}


	#endif