Fix FIFO queue size

machine/cortex-m/src/native.rs

@@ -8,6 +8,7 @@ pub mod debug;
 pub mod excep;
 pub mod gpio;
 pub mod i2c;
+pub mod mcu_temp;
 pub mod panic;
 pub mod sched;
 pub mod spi;

machine/cortex-m/src/native/mcu_temp.rs

@@ -0,0 +1,16 @@
+//! MCU internal junction-temperature sensor.
+
+use hal_api::{PosixError, Result};
+
+use super::bindings;
+
+/// Read the MCU die temperature in degrees Celsius.
+///
+/// Returns `EIO` if ADC init or conversion failed.
+pub fn read() -> Result<f32> {
+    let millidegc = unsafe { bindings::hal_mcu_temp_millidegc() };
+    if millidegc == i32::MIN {
+        return Err(PosixError::EIO);
+    }
+    Ok(millidegc as f32 / 1000.0)
+}

machine/cortex-m/src/stub.rs

@@ -6,6 +6,7 @@ pub mod can;
 pub mod device_tree;
 pub mod gpio;
 pub mod i2c;
+pub mod mcu_temp;
 pub mod sched;
 pub mod spi;
 pub mod system;

machine/cortex-m/src/stub/mcu_temp.rs

@@ -0,0 +1,8 @@
+//! MCU internal junction-temperature sensor (host stub).
+
+use hal_api::Result;
+
+/// Return a fixed dummy temperature on the host build.
+pub fn read() -> Result<f32> {
+    Ok(25.0)
+}

machine/cortex-m/st/stm32l4/interface/export.h

@@ -253,3 +253,10 @@ unsigned long long monotonic_freq(void);
 void delay_us(uint32_t delay_us);
 void do_tick(void);
 void tim2_hndlr(void);
+
+// mcu_temp.c
+// Sentinel returned on init/conversion failure.
+#define HAL_MCU_TEMP_ERROR INT32_MIN
+// Reads the MCU internal junction temperature, in milli-degrees Celsius,
+// or HAL_MCU_TEMP_ERROR on failure.
+int32_t hal_mcu_temp_millidegc(void);

machine/cortex-m/st/stm32l4/interface/mcu_temp.c

@@ -0,0 +1,130 @@
+/*
+ * STM32L4 internal junction-temperature-sensor reading.
+ *
+ * Reads ADC1 channel 17 (ADC_CHANNEL_TEMPSENSOR), the on-die temperature
+ * sensor, and converts the raw code to a temperature using the factory
+ * calibration values.
+ *
+ * Reference: RM0432 (STM32L4+ reference manual) section 21.4.32
+ * "Temperature sensor". The sensor needs a long ADC sampling time
+ * (640.5 cycles here) for its high output impedance to settle.
+ *
+ * Conversion formula (applied by __HAL_ADC_CALC_TEMPERATURE):
+ *
+ *   T = (TS_CAL2_TEMP - TS_CAL1_TEMP)
+ *       --------------------------------- * (TS_DATA - TS_CAL1) + TS_CAL1_TEMP
+ *       (TS_CAL2       - TS_CAL1)
+ *
+ * where TS_CAL1/TS_CAL2 are the factory-programmed ADC codes at the two
+ * calibration temperatures, read from CMSIS-defined addresses. The macro
+ * also rescales TS_DATA for VREF+ (calibration was performed at 3.0 V) and
+ * for ADC resolution. The typical-slope (Avg_Slope / V25) formula is NOT
+ * used: it is inaccurate on STM32L4.
+ */
+
+#include "mcu_temp.h"
+
+#include "stm32l4xx_hal.h"
+#include "stm32l4xx_hal_adc.h"
+#include "stm32l4xx_hal_adc_ex.h"
+
+/* Nucleo VREF+ in millivolts; the temperature macro scales for it. */
+#define MCU_TEMP_VDDA_MV 3300U
+
+/* Samples averaged per read to reduce noise. */
+#define MCU_TEMP_SAMPLES 16U
+
+/* Per-conversion poll timeout, milliseconds. */
+#define MCU_TEMP_CONV_TIMEOUT_MS 10U
+
+int32_t hal_mcu_temp_millidegc(void)
+{
+  ADC_HandleTypeDef hadc = {0};
+  ADC_ChannelConfTypeDef chan = {0};
+
+  __HAL_RCC_ADC_CLK_ENABLE();
+
+  /* ADC1, single conversion, software trigger, 12-bit right-aligned.
+   * Synchronous clock from PCLK2 divided by 4: 80 MHz / 4 = 20 MHz,
+   * within the STM32L4 datasheet ADC clock maximum. */
+  hadc.Instance = ADC1;
+  hadc.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
+  hadc.Init.Resolution = ADC_RESOLUTION_12B;
+  hadc.Init.DataAlign = ADC_DATAALIGN_RIGHT;
+  hadc.Init.ScanConvMode = ADC_SCAN_DISABLE;
+  hadc.Init.EOCSelection = ADC_EOC_SINGLE_CONV;
+  hadc.Init.LowPowerAutoWait = DISABLE;
+  hadc.Init.ContinuousConvMode = DISABLE;
+  hadc.Init.NbrOfConversion = 1;
+  hadc.Init.DiscontinuousConvMode = DISABLE;
+  hadc.Init.ExternalTrigConv = ADC_SOFTWARE_START;
+  hadc.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
+  hadc.Init.DMAContinuousRequests = DISABLE;
+  hadc.Init.Overrun = ADC_OVR_DATA_OVERWRITTEN;
+  hadc.Init.OversamplingMode = DISABLE;
+
+  if (HAL_ADC_Init(&hadc) != HAL_OK)
+  {
+    return HAL_MCU_TEMP_ERROR;
+  }
+
+  /* Internal temperature sensor on regular rank 1. The longest sample
+   * time available is required for the sensor's settling (RM0432
+   * section 21.4.32). */
+  chan.Channel = ADC_CHANNEL_TEMPSENSOR;
+  chan.Rank = ADC_REGULAR_RANK_1;
+  chan.SamplingTime = ADC_SAMPLETIME_640CYCLES_5;
+  chan.SingleDiff = ADC_SINGLE_ENDED;
+  chan.OffsetNumber = ADC_OFFSET_NONE;
+  chan.Offset = 0;
+
+  if (HAL_ADC_ConfigChannel(&hadc, &chan) != HAL_OK)
+  {
+    HAL_ADC_DeInit(&hadc);
+    return HAL_MCU_TEMP_ERROR;
+  }
+
+  /* Calibrate the ADC once before the first conversion. */
+  if (HAL_ADCEx_Calibration_Start(&hadc, ADC_SINGLE_ENDED) != HAL_OK)
+  {
+    HAL_ADC_DeInit(&hadc);
+    return HAL_MCU_TEMP_ERROR;
+  }
+
+  /* Average MCU_TEMP_SAMPLES conversions. */
+  uint32_t accum = 0;
+  for (uint32_t i = 0; i < MCU_TEMP_SAMPLES; i++)
+  {
+    if (HAL_ADC_Start(&hadc) != HAL_OK)
+    {
+      HAL_ADC_DeInit(&hadc);
+      return HAL_MCU_TEMP_ERROR;
+    }
+    if (HAL_ADC_PollForConversion(&hadc, MCU_TEMP_CONV_TIMEOUT_MS) != HAL_OK)
+    {
+      HAL_ADC_Stop(&hadc);
+      HAL_ADC_DeInit(&hadc);
+      return HAL_MCU_TEMP_ERROR;
+    }
+    accum += HAL_ADC_GetValue(&hadc);
+    HAL_ADC_Stop(&hadc);
+  }
+
+  HAL_ADC_DeInit(&hadc);
+
+  uint32_t adc_data = accum / MCU_TEMP_SAMPLES;
+
+  /* Guard the divide-by-zero in the conversion (TS_CAL2 == TS_CAL1).
+   * This cannot happen on real silicon but keeps the shim defensive. */
+  if ((int32_t)*TEMPSENSOR_CAL2_ADDR == (int32_t)*TEMPSENSOR_CAL1_ADDR)
+  {
+    return HAL_MCU_TEMP_ERROR;
+  }
+
+  /* __HAL_ADC_CALC_TEMPERATURE yields whole degrees Celsius; scale to
+   * milli-degrees for the integer interface. */
+  int32_t degc = __HAL_ADC_CALC_TEMPERATURE(MCU_TEMP_VDDA_MV, adc_data,
+                                            ADC_RESOLUTION_12B);
+
+  return degc * 1000;
+}

machine/cortex-m/st/stm32l4/interface/mcu_temp.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <stdint.h>
+
+/* Sentinel returned on init/conversion failure (see export.h). */
+#define HAL_MCU_TEMP_ERROR INT32_MIN
+
+/* Read the STM32L4 internal junction temperature sensor.
+ * Returns the die temperature in milli-degrees Celsius, or
+ * HAL_MCU_TEMP_ERROR on failure. */
+int32_t hal_mcu_temp_millidegc(void);

machine/cortex-m/st/stm32l4/interface/spi.c

@@ -317,6 +317,13 @@ static int spi_select_device(void *bus, const spi_device_cfg_t *dev_cfg)
         LL_SPI_SetClockPolarity(hspi->Instance, polarity);
         LL_SPI_SetClockPhase(hspi->Instance, phase);
         LL_SPI_SetDataWidth(hspi->Instance, datasize);
+        /* FRXTH must track the data width, or RXNE fires at the wrong FIFO
+         * level and >8-bit reads return corrupt data: half-full for >8-bit
+         * words, quarter-full otherwise. */
+        LL_SPI_SetRxFIFOThreshold(
+            hspi->Instance,
+            dev_cfg->bits_per_word > 8 ? LL_SPI_RX_FIFO_TH_HALF
+                                      : LL_SPI_RX_FIFO_TH_QUARTER);
         LL_SPI_SetTransferBitOrder(hspi->Instance, bit_order);
 
         __HAL_SPI_ENABLE(hspi);