STM32F1: Sync SPI changes from maple master (#15266)

Marlin/src/HAL/HAL_STM32F1/SPI.cpp

     // FIXME [0.1.0] remove this once you have an interrupt based driver
     volatile uint16_t rx __attribute__((unused)) = spi_rx_reg(_currentSetting->spi_d);
   }
-  while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ }
-  while (spi_is_busy(_currentSetting->spi_d)) { /* nada */ }
+  waitSpiTxEnd(_currentSetting->spi_d);
 
   spi_peripheral_disable(_currentSetting->spi_d);
   // added for DMA callbacks.
    * This almost doubles the speed of this function.
    */
   spi_tx_reg(_currentSetting->spi_d, data); // write the data to be transmitted into the SPI_DR register (this clears the TXE flag)
-  while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ } // "5. Wait until TXE=1 ..."
-  while (spi_is_busy(_currentSetting->spi_d)) { /* nada */ } // "... and then wait until BSY=0 before disabling the SPI."
+  waitSpiTxEnd(_currentSetting->spi_d);
 }
 
 void SPIClass::write16(uint16_t data) {
   spi_tx_reg(_currentSetting->spi_d, data>>8); // write high byte
   while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ } // Wait until TXE=1
   spi_tx_reg(_currentSetting->spi_d, data); // write low byte
-  while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ } // Wait until TXE=1
-  while (spi_is_busy(_currentSetting->spi_d)) { /* nada */ } // wait until BSY=0
+  waitSpiTxEnd(_currentSetting->spi_d);
 }
 
 void SPIClass::write(uint16_t data, uint32_t n) {
 void SPIClass::write(const void *data, uint32_t length) {
   spi_dev * spi_d = _currentSetting->spi_d;
   spi_tx(spi_d, data, length); // data can be array of bytes or words
-  while (!spi_is_tx_empty(spi_d)) { /* nada */ } // "5. Wait until TXE=1 ..."
-  while (spi_is_busy(spi_d)) { /* nada */ } // "... and then wait until BSY=0 before disabling the SPI."
+  waitSpiTxEnd(spi_d);
 }
 
 uint8_t SPIClass::transfer(uint8_t byte) const {
   spi_dev * spi_d = _currentSetting->spi_d;
   spi_rx_reg(spi_d); // read any previous data
   spi_tx_reg(spi_d, byte); // Write the data item to be transmitted into the SPI_DR register
-  while (!spi_is_tx_empty(spi_d)) { /* nada */ } // "5. Wait until TXE=1 ..."
-  while (spi_is_busy(spi_d)) { /* nada */ } // "... and then wait until BSY=0 before disabling the SPI."
+  waitSpiTxEnd(spi_d);
   return (uint8)spi_rx_reg(spi_d); // "... and read the last received data."
 }
 
   spi_dev * spi_d = _currentSetting->spi_d;
   spi_rx_reg(spi_d);                              // read any previous data
   spi_tx_reg(spi_d, data>>8);                     // write high byte
-  while (!spi_is_tx_empty(spi_d)) { /* nada */ }  // wait until TXE=1
-  while (spi_is_busy(spi_d)) { /* nada */ }       // wait until BSY=0
+  waitSpiTxEnd(spi_d);                            // wait until TXE=1 and then wait until BSY=0
   uint16_t ret = spi_rx_reg(spi_d)<<8;            // read and shift high byte
   spi_tx_reg(spi_d, data);                        // write low byte
-  while (!spi_is_tx_empty(spi_d)) { /* nada */ }  // wait until TXE=1
-  while (spi_is_busy(spi_d)) { /* nada */ }       // wait until BSY=0
+  waitSpiTxEnd(spi_d);                            // wait until TXE=1 and then wait until BSY=0
   ret += spi_rx_reg(spi_d);                       // read low byte
   return ret;
 }
     if ((millis() - m) > DMA_TIMEOUT) { b = 2; break; }
   }
 
-  while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ } // "5. Wait until TXE=1 ..."
-  while (spi_is_busy(_currentSetting->spi_d)) { /* nada */ } // "... and then wait until BSY=0 before disabling the SPI."
+  waitSpiTxEnd(_currentSetting->spi_d); // until TXE=1 and BSY=0
   spi_tx_dma_disable(_currentSetting->spi_d);
   spi_rx_dma_disable(_currentSetting->spi_d);
   dma_disable(_currentSetting->spiDmaDev, _currentSetting->spiTxDmaChannel);
     // Avoid interrupts and just loop waiting for the flag to be set.
     if ((millis() - m) > DMA_TIMEOUT) { b = 2; break; }
   }
-  while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ } // "5. Wait until TXE=1 ..."
-  while (spi_is_busy(_currentSetting->spi_d)) { /* nada */ } // "... and then wait until BSY=0 before disabling the SPI."
+  waitSpiTxEnd(_currentSetting->spi_d); // until TXE=1 and BSY=0
   spi_tx_dma_disable(_currentSetting->spi_d);
   dma_disable(_currentSetting->spiDmaDev, _currentSetting->spiTxDmaChannel);
   dma_clear_isr_bits(_currentSetting->spiDmaDev, _currentSetting->spiTxDmaChannel);
       //delayMicroseconds(10);
       if ((millis() - m) > DMA_TIMEOUT) { b = 2; break; }
     }
-
-    while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ } // "5. Wait until TXE=1 ..."
-    while (spi_is_busy(_currentSetting->spi_d)) { /* nada */ } // "... and then wait until BSY=0 before disabling the SPI."
+    waitSpiTxEnd(_currentSetting->spi_d); // until TXE=1 and BSY=0
     spi_tx_dma_disable(_currentSetting->spi_d);
     dma_disable(_currentSetting->spiDmaDev, _currentSetting->spiTxDmaChannel);
     _currentSetting->state = SPI_STATE_READY;
  * during the initial setup and only set the callback to EventCallback if they are set.
  */
 void SPIClass::EventCallback() {
-  while (!spi_is_tx_empty(_currentSetting->spi_d)) { /* nada */ } // "5. Wait until TXE=1 ..."
-  while (spi_is_busy(_currentSetting->spi_d)) { /* nada */ } // "... and then wait until BSY=0"
+  waitSpiTxEnd(_currentSetting->spi_d);
   switch (_currentSetting->state) {
   case SPI_STATE_TRANSFER:
     while (spi_is_rx_nonempty(_currentSetting->spi_d)) { /* nada */ }

Marlin/src/HAL/HAL_STM32F1/SPI.h

   */
 };
 
+/**
+ * @brief Wait until TXE (tx empty) flag is set and BSY (busy) flag unset.
+ */
+static inline void waitSpiTxEnd(spi_dev *spi_d) {
+  while (spi_is_tx_empty(spi_d) == 0) { /* nada */ } // wait until TXE=1
+  while (spi_is_busy(spi_d) != 0) { /* nada */ }     // wait until BSY=0
+}
+
 extern SPIClass SPI;