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Code Issues Wiki Activity

Fix DShot cache clean/invalidate

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This commit is contained in:
Steve Evans 2020-11-02 22:36:00 +00:00 • committed by Steve Evans
parent 76765cd0e8
commit 080717a407
3 changed files with 69 additions and 13 deletions
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51
src/main/drivers/dshot_bitbang.c
View file

@ -69,7 +69,10 @@ dshotBitbangStatus_e bbStatus;
// on manipulating input buffer content especially if it is read multiple times,
// as the buffer region is attributed as not cachable.
// If this is not desirable, we should use manual cache invalidation.
#ifdef USE_DSHOT_CACHE_MGMT
#define BB_OUTPUT_BUFFER_ATTRIBUTE __attribute__((aligned(32)))
#define BB_INPUT_BUFFER_ATTRIBUTE __attribute__((aligned(32)))
#else
#if defined(STM32F4)
#define BB_OUTPUT_BUFFER_ATTRIBUTE
#define BB_INPUT_BUFFER_ATTRIBUTE
@ -77,15 +80,16 @@ dshotBitbangStatus_e bbStatus;
#define BB_OUTPUT_BUFFER_ATTRIBUTE FAST_DATA_ZERO_INIT
#define BB_INPUT_BUFFER_ATTRIBUTE FAST_DATA_ZERO_INIT
#elif defined(STM32H7)
#define BB_OUTPUT_BUFFER_ATTRIBUTE __attribute__((aligned(32)))
#define BB_INPUT_BUFFER_ATTRIBUTE __attribute__((aligned(32)))
#define BB_OUTPUT_BUFFER_ATTRIBUTE DMA_RAM
#define BB_INPUT_BUFFER_ATTRIBUTE DMA_RAM
#elif defined(STM32G4)
#define BB_OUTPUT_BUFFER_ATTRIBUTE DMA_RAM_W
#define BB_INPUT_BUFFER_ATTRIBUTE DMA_RAM_R
#endif
#endif // USE_DSHOT_CACHE_MGMT
BB_OUTPUT_BUFFER_ATTRIBUTE uint32_t bbOutputBuffer[MOTOR_DSHOT_BUFFER_SIZE * MAX_SUPPORTED_MOTOR_PORTS];
BB_INPUT_BUFFER_ATTRIBUTE uint16_t bbInputBuffer[DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
BB_OUTPUT_BUFFER_ATTRIBUTE uint32_t bbOutputBuffer[MOTOR_DSHOT_BUF_CACHE_ALIGN_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
BB_INPUT_BUFFER_ATTRIBUTE uint16_t bbInputBuffer[DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
uint8_t bbPuPdMode;
FAST_DATA_ZERO_INIT timeUs_t dshotFrameUs;
@ -423,11 +427,11 @@ static bool bbMotorConfig(IO_t io, uint8_t motorIndex, motorPwmProtocolTypes_e p
bbPort->gpio = IO_GPIO(io);
bbPort->portOutputCount = MOTOR_DSHOT_BUFFER_SIZE;
bbPort->portOutputBuffer = &bbOutputBuffer[(bbPort - bbPorts) * MOTOR_DSHOT_BUFFER_SIZE];
bbPort->portOutputCount = MOTOR_DSHOT_BUF_LENGTH;
bbPort->portOutputBuffer = &bbOutputBuffer[(bbPort - bbPorts) * MOTOR_DSHOT_BUF_CACHE_ALIGN_LENGTH];
bbPort->portInputCount = DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH;
bbPort->portInputBuffer = &bbInputBuffer[(bbPort - bbPorts) * DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH];
bbPort->portInputCount = DSHOT_BB_PORT_IP_BUF_LENGTH;
bbPort->portInputBuffer = &bbInputBuffer[(bbPort - bbPorts) * DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_LENGTH];
bbTimebaseSetup(bbPort, pwmProtocolType);
bbTIM_TimeBaseInit(bbPort, bbPort->outputARR);
@ -481,6 +485,20 @@ static bool bbUpdateStart(void)
}
for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < motorCount; motorIndex++) {
#ifdef USE_DSHOT_CACHE_MGMT
// Only invalidate the buffer once. If all motors are on a common port they'll share a buffer.
bool invalidated = false;
for (int i = 0; i < motorIndex; i++) {
if (bbMotors[motorIndex].bbPort->portInputBuffer == bbMotors[i].bbPort->portInputBuffer) {
invalidated = true;
}
}
if (!invalidated) {
SCB_InvalidateDCache_by_Addr((uint32_t *)bbMotors[motorIndex].bbPort->portInputBuffer,
DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_BYTES);
}
#endif
#ifdef STM32F4
uint32_t value = decode_bb_bitband(
bbMotors[motorIndex].bbPort->portInputBuffer,
@ -572,6 +590,21 @@ static void bbUpdateComplete(void)
}
}
#ifdef USE_DSHOT_CACHE_MGMT
for (int motorIndex = 0; motorIndex < MAX_SUPPORTED_MOTORS && motorIndex < motorCount; motorIndex++) {
// Only clean the buffer once. If all motors are on a common port they'll share a buffer.
bool clean = false;
for (int i = 0; i < motorIndex; i++) {
if (bbMotors[motorIndex].bbPort->portInputBuffer == bbMotors[i].bbPort->portInputBuffer) {
clean = true;
}
}
if (!clean) {
SCB_CleanDCache_by_Addr(bbMotors[motorIndex].bbPort->portOutputBuffer, MOTOR_DSHOT_BUF_CACHE_ALIGN_BYTES);
}
}
#endif
#ifdef USE_DSHOT_TELEMETRY
for (int i = 0; i < usedMotorPorts; i++) {
bbPort_t *bbPort = &bbPorts[i];

30
src/main/drivers/dshot_bitbang_impl.h
View file

@ -62,7 +62,18 @@
#define MOTOR_DSHOT_GCR_CHANGE_INTERVAL_NS(rate) (MOTOR_DSHOT_CHANGE_INTERVAL_NS(rate) * 5 / 4)
#define MOTOR_DSHOT_BUFFER_SIZE ((MOTOR_DSHOT_FRAME_BITS / MOTOR_DSHOT_BIT_PER_SYMBOL) * MOTOR_DSHOT_STATE_PER_SYMBOL)
#define MOTOR_DSHOT_BUF_LENGTH ((MOTOR_DSHOT_FRAME_BITS / MOTOR_DSHOT_BIT_PER_SYMBOL) * MOTOR_DSHOT_STATE_PER_SYMBOL)
#ifdef USE_DSHOT_CACHE_MGMT
// MOTOR_DSHOT_BUF_LENGTH is multiples of uint32_t
// Number of bytes required for buffer
#define MOTOR_DSHOT_BUF_BYTES (MOTOR_DSHOT_BUF_LENGTH * sizeof (uint32_t))
// Number of bytes required to cache align buffer
#define MOTOR_DSHOT_BUF_CACHE_ALIGN_BYTES ((MOTOR_DSHOT_BUF_BYTES + 0x20) & ~0x1f)
// Size of array to create a cache aligned buffer
#define MOTOR_DSHOT_BUF_CACHE_ALIGN_LENGTH (MOTOR_DSHOT_BUF_CACHE_ALIGN_BYTES / sizeof (uint32_t))
#else
#define MOTOR_DSHOT_BUF_CACHE_ALIGN_LENGTH MOTOR_DSHOT_BUF_LENGTH
#endif
#ifdef USE_HAL_DRIVER
#define BB_GPIO_PULLDOWN GPIO_PULLDOWN
@ -195,7 +206,7 @@ extern uint8_t bbPuPdMode;
// DMA output buffer:
// DShot requires 3 [word/bit] * 16 [bit] = 48 [word]
extern uint32_t bbOutputBuffer[MOTOR_DSHOT_BUFFER_SIZE * MAX_SUPPORTED_MOTOR_PORTS];
extern uint32_t bbOutputBuffer[MOTOR_DSHOT_BUF_CACHE_ALIGN_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
// DMA input buffer
// (30us + <frame time> + <slack>) / <input sampling clock perid>
@ -206,8 +217,19 @@ extern uint32_t bbOutputBuffer[MOTOR_DSHOT_BUFFER_SIZE * MAX_SUPPORTED_MOTOR_POR
// <slack> = 10%
// (30 + 26 + 3) / 0.44 = 134
// In some cases this was not enough, so we add 6 extra samples
#define DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH 140
extern uint16_t bbInputBuffer[DSHOT_BITBANG_PORT_INPUT_BUFFER_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
#define DSHOT_BB_PORT_IP_BUF_LENGTH 140
#ifdef USE_DSHOT_CACHE_MGMT
// Each sample is a uint16_t
// Number of bytes required for buffer
#define DSHOT_BB_PORT_IP_BUF_BYTES (DSHOT_BB_PORT_IP_BUF_LENGTH * sizeof (uint16_t))
// Number of bytes required to cache align buffer
#define DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_BYTES ((DSHOT_BB_PORT_IP_BUF_BYTES + 0x20) & ~0x1f)
// Size of array to create a cache aligned buffer
#define DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_LENGTH (DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_BYTES / sizeof (uint16_t))
#else
#define DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_LENGTH DSHOT_BB_PORT_IP_BUF_LENGTH
#endif
extern uint16_t bbInputBuffer[DSHOT_BB_PORT_IP_BUF_CACHE_ALIGN_LENGTH * MAX_SUPPORTED_MOTOR_PORTS];
void bbGpioSetup(bbMotor_t *bbMotor);
void bbTimerChannelInit(bbPort_t *bbPort);

1
src/main/target/common_pre.h
View file

@ -123,6 +123,7 @@
#define USE_USB_MSC
#define USE_RTC_TIME
#define USE_PERSISTENT_MSC_RTC
#define USE_DSHOT_CACHE_MGMT
#endif
#ifdef STM32G4