add SPI slave support

Set up SPI slave transactions for entries in the SPI send queue.
Add a header to each SPI datagram that includes a CRC16,
the type and the size of the message that follows.

Does not act on received bytes (yet).

Signed-off-by: Christian Ambach <christian.ambach@deutschebahn.com>

include/globals.h

@@ -66,10 +66,6 @@ extern TaskHandle_t irqHandlerTask, wifiSwitchTask;
 #include "lorawan.h"
 #endif
 
-#ifdef HAS_SPI
-#include "spisend.h"
-#endif
-
 #ifdef HAS_DISPLAY
 #include "display.h"
 #endif

include/spisend.h

@@ -1,9 +0,0 @@
-#ifndef _SPISEND_H
-#define _SPISEND_H
-
-extern TaskHandle_t SpiTask;
-extern QueueHandle_t SPISendQueue;
-
-void spi_loop(void *pvParameters);
-
-#endif

include/spislave.h

@@ -0,0 +1,36 @@
+/*
+
+//////////////////////// ESP32-Paxcounter \\\\\\\\\\\\\\\\\\\\\\\\\\
+
+Copyright  2018 Christian Ambach <christian.ambach@deutschebahn.com>
+
+   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.
+
+NOTICE:
+Parts of the source files in this repository are made available under different
+licenses. Refer to LICENSE.txt file in repository for more details.
+
+*/
+#ifndef _SPISLAVE_H
+#define _SPISLAVE_H
+
+#include "globals.h"
+
+esp_err_t spi_init();
+
+void spi_enqueuedata(uint8_t messageType, MessageBuffer_t *message);
+void spi_queuereset();
+
+void spi_housekeeping();
+
+#endif // _SPISLAVE_H

src/cyclic.cpp

@@ -4,6 +4,7 @@
 // Basic config
 #include "cyclic.h"
 #include "rcommand.h"
+#include "spislave.h"
 
 // Local logging tag
 static const char TAG[] = "main";
@@ -26,9 +27,9 @@ void doHousekeeping() {
 #ifdef HAS_GPS
   ESP_LOGD(TAG, "Gpsloop %d bytes left", uxTaskGetStackHighWaterMark(GpsTask));
 #endif
-#ifdef HAS_SPI
+
-  ESP_LOGD(TAG, "Spiloop %d bytes left", uxTaskGetStackHighWaterMark(SpiTask));
+  spi_housekeeping();
-#endif
+
 #if (HAS_LED != NOT_A_PIN) || defined(HAS_RGB_LED)
   ESP_LOGD(TAG, "LEDloop %d bytes left", uxTaskGetStackHighWaterMark(ledLoopTask));
 #endif

src/hal/generic.h

@@ -7,6 +7,11 @@
 
 #define HAS_LORA 1 // comment out if device shall not send data via LoRa or has no LoRa
 #define HAS_SPI 1  // comment out if device shall not send data via SPI
+// pin definitions for SPI slave interface
+#define SPI_MOSI GPIO_NUM_23
+#define SPI_MISO GPIO_NUM_19
+#define SPI_SCLK GPIO_NUM_18
+#define SPI_CS GPIO_NUM_5
 
 #define CFG_sx1276_radio 1 // select LoRa chip
 //#define CFG_sx1272_radio 1 // select LoRa chip

src/hal/lopy4.h

@@ -7,6 +7,12 @@
 
 #define HAS_LORA 1       // comment out if device shall not send data via LoRa
 #define HAS_SPI 1        // comment out if device shall not send data via SPI
+// pin definitions for SPI slave interface
+#define SPI_MOSI GPIO_NUM_22
+#define SPI_MISO GPIO_NUM_33
+#define SPI_SCLK GPIO_NUM_26
+#define SPI_CS GPIO_NUM_36
+
 #define CFG_sx1276_radio 1
 //#define HAS_LED NOT_A_PIN // LoPy4 has no on board mono LED, we use on board RGB LED
 #define HAS_RGB_LED (0)  // WS2812B RGB LED on GPIO0 (P2)

src/main.cpp

@@ -48,6 +48,7 @@ ESP32 hardware timers
 
 // Basic Config
 #include "main.h"
+#include "spislave.h"
 
 configData_t cfg; // struct holds current device configuration
 char display_line6[16], display_line7[16]; // display buffers
@@ -197,14 +198,8 @@ void setup() {
 // initialize SPI
 #ifdef HAS_SPI
   strcat_P(features, " SPI");
-  SPISendQueue = xQueueCreate(SEND_QUEUE_SIZE, sizeof(MessageBuffer_t));
-  if (SPISendQueue == 0) {
-    ESP_LOGE(TAG, "Could not create SPI send queue. Aborting.");
-    exit(0);
-  } else
-    ESP_LOGI(TAG, "SPI send queue created, size %d Bytes",
-             SEND_QUEUE_SIZE * PAYLOAD_BUFFER_SIZE);
 #endif
+  assert(spi_init() == ESP_OK);
 
 #ifdef VENDORFILTER
   strcat_P(features, " OUIFLT");
@@ -312,17 +307,6 @@ void setup() {
                           1);        // CPU core
 #endif
 
-#ifdef HAS_SPI
-  ESP_LOGI(TAG, "Starting SPIloop...");
-  xTaskCreatePinnedToCore(spi_loop,  // task function
-                          "spiloop", // name of task
-                          2048,      // stack size of task
-                          (void *)1, // parameter of the task
-                          2,         // priority of the task
-                          &SpiTask,  // task handle
-                          0);        // CPU core
-#endif
-
   // start state machine
   ESP_LOGI(TAG, "Starting IRQ Handler...");
   xTaskCreatePinnedToCore(irqHandler,      // task function

src/senddata.cpp

@@ -1,5 +1,6 @@
 // Basic Config
 #include "globals.h"
+#include "spislave.h"
 
 // put data to send in RTos Queues used for transmit over channels Lora and SPI
 void SendData(uint8_t port) {
@@ -19,12 +20,7 @@ void SendData(uint8_t port) {
     ESP_LOGI(TAG, "%d bytes enqueued to send on LoRa", payload.getSize());
 #endif
 
-// enqueue message in SPI send queue
+  spi_enqueuedata(port, &SendBuffer);
-#ifdef HAS_SPI
-  if (xQueueSendToBack(SPISendQueue, (void *)&SendBuffer, (TickType_t)0) ==
-      pdTRUE)
-    ESP_LOGI(TAG, "%d bytes enqueued to send on SPI", payload.getSize());
-#endif
 
   // clear counter if not in cumulative counter mode
   if ((port == COUNTERPORT) && (cfg.countermode != 1)) {
@@ -66,7 +62,6 @@ void flushQueues() {
 #ifdef HAS_LORA
   xQueueReset(LoraSendQueue);
 #endif
-#ifdef HAS_SPI
+
-  xQueueReset(SPISendQueue);
+  spi_queuereset();
-#endif
 }

src/spisend.cpp

@@ -1,30 +0,0 @@
-#ifdef HAS_SPI
-
-#include "globals.h"
-
-// Local logging tag
-static const char TAG[] = "main";
-
-MessageBuffer_t SendBuffer;
-
-QueueHandle_t SPISendQueue;
-TaskHandle_t SpiTask;
-
-// SPI feed Task
-void spi_loop(void *pvParameters) {
-
-  configASSERT(((uint32_t)pvParameters) == 1); // FreeRTOS check
-
-  while (1) {
-    if (xQueueReceive(SPISendQueue, &SendBuffer, (TickType_t)0) == pdTRUE) {
-      ESP_LOGI(TAG, "%d bytes sent to SPI", SendBuffer.MessageSize);
-    }
-    vTaskDelay(2 / portTICK_PERIOD_MS); // yield to CPU
-
-  } // end of infinite loop
-
-  vTaskDelete(NULL); // shoud never be reached
-
-} // spi_loop()
-
-#endif // HAS_SPI

src/spislave.cpp

@@ -0,0 +1,152 @@
+/*
+
+//////////////////////// ESP32-Paxcounter \\\\\\\\\\\\\\\\\\\\\\\\\\
+
+Copyright  2018 Christian Ambach <christian.ambach@deutschebahn.com>
+
+   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.
+
+NOTICE:
+Parts of the source files in this repository are made available under different
+licenses. Refer to LICENSE.txt file in repository for more details.
+
+*/
+
+#include "spislave.h"
+
+#include <driver/spi_slave.h>
+#include <sys/param.h>
+#include <rom/crc.h>
+
+static const char TAG[] = __FILE__;
+
+#define HEADER_SIZE 4
+// SPI transaction size needs to be at least 8 bytes and dividable by 4, see
+// https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/peripherals/spi_slave.html
+#define BUFFER_SIZE                                                            \
+  (MAX(8, HEADER_SIZE + PAYLOAD_BUFFER_SIZE) +                                 \
+   (4 - MAX(8, HEADER_SIZE + PAYLOAD_BUFFER_SIZE) % 4))
+DMA_ATTR uint8_t txbuf[BUFFER_SIZE];
+DMA_ATTR uint8_t rxbuf[BUFFER_SIZE];
+
+QueueHandle_t SPISendQueue;
+
+TaskHandle_t spiTask;
+
+void spi_slave_task(void *param) {
+  while (1) {
+    MessageBuffer_t msg;
+    size_t transaction_size;
+
+    memset(txbuf, 0, sizeof(txbuf));
+    memset(rxbuf, 0, sizeof(rxbuf));
+
+    if (xQueueReceive(SPISendQueue, &msg, portMAX_DELAY) != pdTRUE) {
+      ESP_LOGE(TAG, "Premature return from xQueueReceive() with no data!");
+      continue;
+    }
+
+    uint8_t *messageType = txbuf + 2;
+    *messageType = msg.MessagePort;
+    uint8_t *messageSize = txbuf + 3;
+    *messageSize = msg.MessageSize;
+    memcpy(txbuf + HEADER_SIZE, &msg.Message, msg.MessageSize);
+
+    transaction_size = HEADER_SIZE + msg.MessageSize;
+    transaction_size += (4 - transaction_size % 4);
+
+    uint16_t *crc = (uint16_t *)txbuf;
+    *crc = crc16_be(0, messageType, msg.MessageSize + HEADER_SIZE - 2);
+
+    spi_slave_transaction_t spi_transaction = {0};
+    spi_transaction.length = transaction_size * 8;
+    spi_transaction.tx_buffer = txbuf;
+    spi_transaction.rx_buffer = rxbuf;
+
+    ESP_LOGI(TAG, "Prepared SPI transaction for %zu bytes", transaction_size);
+    ESP_LOG_BUFFER_HEXDUMP(TAG, txbuf, transaction_size, ESP_LOG_DEBUG);
+    esp_err_t ret =
+        spi_slave_transmit(HSPI_HOST, &spi_transaction, portMAX_DELAY);
+    ESP_LOG_BUFFER_HEXDUMP(TAG, rxbuf, transaction_size, ESP_LOG_DEBUG);
+    ESP_LOGI(TAG, "Transaction finished with size %zu bits",
+             spi_transaction.trans_len);
+  }
+}
+
+esp_err_t spi_init() {
+#ifndef HAS_SPI
+  return ESP_OK;
+#else
+
+  SPISendQueue = xQueueCreate(SEND_QUEUE_SIZE, sizeof(MessageBuffer_t));
+  if (SPISendQueue == 0) {
+    ESP_LOGE(TAG, "Could not create SPI send queue. Aborting.");
+    return ESP_FAIL;
+  }
+  ESP_LOGI(TAG, "SPI send queue created, size %d Bytes",
+           SEND_QUEUE_SIZE * PAYLOAD_BUFFER_SIZE);
+
+  spi_bus_config_t spi_bus_cfg = {.mosi_io_num = SPI_MOSI,
+                                  .miso_io_num = SPI_MISO,
+                                  .sclk_io_num = SPI_SCLK,
+                                  .quadwp_io_num = -1,
+                                  .quadhd_io_num = -1,
+                                  .max_transfer_sz = 0,
+                                  .flags = 0};
+
+  spi_slave_interface_config_t spi_slv_cfg = {.spics_io_num = SPI_CS,
+                                              .flags = 0,
+                                              .queue_size = 1,
+                                              .mode = 0,
+                                              .post_setup_cb = NULL,
+                                              .post_trans_cb = NULL};
+
+  gpio_set_pull_mode(SPI_MOSI, GPIO_PULLUP_ONLY);
+  gpio_set_pull_mode(SPI_SCLK, GPIO_PULLUP_ONLY);
+  gpio_set_pull_mode(SPI_CS, GPIO_PULLUP_ONLY);
+
+  ESP_LOGI(TAG, "Starting SPIloop...");
+  xTaskCreate(spi_slave_task, "spiloop", 4096, (void *)NULL, 2, &spiTask);
+
+  esp_err_t ret =
+      spi_slave_initialize(HSPI_HOST, &spi_bus_cfg, &spi_slv_cfg, 1);
+  return ret;
+
+#endif
+}
+
+void spi_enqueuedata(uint8_t messageType, MessageBuffer_t *message) {
+  // enqueue message in SPI send queue
+#ifdef HAS_SPI
+  BaseType_t ret =
+      xQueueSendToBack(SPISendQueue, (void *)message, (TickType_t)0);
+  if (ret == pdTRUE) {
+    ESP_LOGI(TAG, "%d bytes enqueued for SPI consumption",
+             message->MessageSize);
+  } else {
+    ESP_LOGW(TAG, "SPI sendqueue is full");
+  }
+#endif
+}
+
+void spi_queuereset(void) {
+#ifdef HAS_SPI
+  xQueueReset(SPISendQueue);
+#endif
+}
+
+void spi_housekeeping(void) {
+#ifdef HAS_SPI
+  ESP_LOGD(TAG, "spiloop %d bytes left", uxTaskGetStackHighWaterMark(spiTask));
+#endif
+}