[apps] Add a lowlevel test app

Change-Id: Id217736cfd39f9994e9d0b4325a52cd63d4a7460

apps/hwtest/lowlevel/Makefile

@@ -0,0 +1,5 @@
+objs += $(addprefix apps/hwtest/lowlevel/,\
+  lowlevel.o \
+)
+
+apps/hwtest/lowlevel/lowlevel.o: SFLAGS += -O3

apps/hwtest/lowlevel/lowlevel.cpp

@@ -0,0 +1,177 @@
+#include <stddef.h>
+
+#include "../../../ion/src/device/regs/regs.h"
+
+// SDIOCK -> SPI2_MOSI
+// SDIO_D2 -> SPI3_CLK == PC10
+// SDIO_D0 -> SPI3_MISO = PB4
+// SDIO_D3 -> SPI3_MOSI = PB5
+//
+//
+
+// On SD card, from left to right
+// D1 - D0 - .... - D3 - D2
+// X - MISO - .... - MOSI - CLK
+
+// On Rpi, from top to bottom
+// MOSI 19
+// MISO 21
+// CLK 23
+// GND 25
+constexpr SPI spiPort = SPI(3);
+
+void init_spi_port() {
+  RCC.APB1ENR()->setSPI3EN(true);
+
+  GPIOB.MODER()->setMode(4, GPIO::MODER::Mode::AlternateFunction);
+  GPIOB.MODER()->setMode(5, GPIO::MODER::Mode::AlternateFunction);
+  GPIOC.MODER()->setMode(10, GPIO::MODER::Mode::AlternateFunction);
+
+  GPIOB.AFR()->setAlternateFunction(4, GPIO::AFR::AlternateFunction::AF6);
+  GPIOB.AFR()->setAlternateFunction(5, GPIO::AFR::AlternateFunction::AF6);
+  GPIOC.AFR()->setAlternateFunction(10, GPIO::AFR::AlternateFunction::AF6);
+
+  spiPort.CR1()->setSPE(true);
+
+  // We don't use a CS wire
+  spiPort.CR1()->setSSM(true);
+  spiPort.CR1()->setSSI(0);
+}
+
+char spi_read_char() {
+  while (spiPort.SR()->getRXNE() == 0) {
+  }
+  return (char)spiPort.DR()->get();
+}
+
+void spi_write_char(char c) {
+  spiPort.DR()->set(c);
+  while (spiPort.SR()->getTXE() == 0) {
+  }
+}
+
+bool readLine(char * buffer, int bufferSize) {
+  char * endBuffer = buffer + bufferSize - 1;
+  while (true) {
+    *buffer = spi_read_char();
+    if (*buffer == NULL) {
+      /* Time for a comment :
+       * - Building DEBUG=0 might make the device fast enough
+       * - Reading on the HOST... ALSO sends data to the device !!
+       *   So we were being overflowed with zeroes here... */
+      continue;
+    }
+    if (*buffer == '\n') {
+      break;
+    }
+    buffer++;
+    if (buffer == endBuffer) {
+      return false;
+    }
+  }
+  *buffer = 0;
+  return true;
+}
+
+void reply(const char * buffer) {
+  while (*buffer != NULL) {
+    spi_write_char(*buffer);
+    buffer++;
+  }
+  spi_write_char('\n');
+  spi_write_char(0);
+}
+
+typedef void (*CommandFunction)(const char * input);
+
+void command_ping(const char * input);
+void command_mcu_serial(const char * input);
+
+class CommandHandler {
+public:
+  constexpr CommandHandler(const char * name, CommandFunction function) :
+    m_name(name), m_function(function) {}
+  bool valid() const;
+  bool handle(const char * command) const;
+private:
+  bool matches(const char * command) const;
+  const char * m_name;
+  CommandFunction m_function;
+};
+
+bool CommandHandler::valid() const {
+  return (m_name != nullptr && m_function != nullptr);
+}
+
+bool CommandHandler::handle(const char * command) const {
+  if (matches(command)) {
+    m_function(command);
+    return true;
+  }
+  return false;
+}
+
+bool CommandHandler::matches(const char * command) const {
+  const char * c = command;
+  const char * n = m_name;
+  while (true) {
+    if (*c != *n) {
+      return false;
+    }
+    if (*n == NULL) {
+      if (*c == NULL || *c == '=') {
+        return true;
+      }
+    }
+    c++;
+    n++;
+  }
+}
+
+class CommandList {
+public:
+  constexpr CommandList(const CommandHandler * handlers) : m_handlers(handlers) {}
+  void dispatch(const char * command) const;
+private:
+  const CommandHandler * m_handlers;
+};
+
+void CommandList::dispatch(const char * command) const {
+  const CommandHandler * handler = m_handlers;
+  while (handler->valid()) {
+    if (handler->handle(command)) {
+      return;
+    }
+    handler++;
+  }
+  reply("NOT_FOUND");
+}
+
+constexpr CommandHandler handles[] = {
+  CommandHandler("PING", command_ping),
+  CommandHandler("MCU_SERIAL", command_mcu_serial),
+  CommandHandler(nullptr, nullptr)
+};
+
+constexpr const CommandList sCommandList = CommandList(handles);
+
+void command_ping(const char * input) {
+  reply("PONG");
+}
+
+void command_mcu_serial(const char * input) {
+  reply("UNKNOWN");
+}
+
+constexpr int kMaxCommandLength = 255;
+
+void ion_app() {
+  init_spi_port();
+  char command[kMaxCommandLength];
+  while (true) {
+    if (readLine(command, kMaxCommandLength)) {
+      sCommandList.dispatch(command);
+    }
+  }
+}
+