[sw] Add test for RGB LED controller

sw/cheri/tests/CMakeLists.txt

@@ -4,6 +4,7 @@ set(TESTS
   uart_check.cc
   spi_test.cc
   revocation_test.cc
+  rgbled_test.cc
 )
 
 foreach(TEST ${TESTS})

sw/cheri/tests/rgbled_test.cc

@@ -0,0 +1,98 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#define CHERIOT_NO_AMBIENT_MALLOC
+#define CHERIOT_NO_NEW_DELETE
+
+#include "../../common/defs.h"
+
+#include <cheri.hh>
+#include <riscvreg.h>
+#include <stdint.h>
+
+using namespace CHERI;
+
+struct SonataRGBLEDCtrl
+{
+  uint32_t rgbled0;
+  uint32_t rgbled1;
+  uint32_t ctrl;
+  uint32_t status;
+
+  void wait_idle() volatile
+  {
+    while ((status & 0x1) == 0);
+  }
+
+  void set_rgb(uint8_t r, uint8_t g, uint8_t b, uint32_t led) volatile
+  {
+    uint32_t rgb;
+
+    rgb = (uint32_t)r | ((uint32_t)g << 8) | ((uint32_t)b << 16);
+
+    wait_idle();
+
+    if (led == 0) {
+      rgbled0 = rgb;
+    } else if (led == 1) {
+      rgbled1 = rgb;
+    }
+  }
+
+  void update() volatile
+  {
+    wait_idle();
+    ctrl = 0x1;
+  }
+
+  void clear() volatile
+  {
+    wait_idle();
+    ctrl = 0x2;
+  }
+};
+
+void busy_wait(uint64_t cycles)
+{
+  uint64_t end = rdcycle64() + cycles;
+  while(rdcycle64() < end);
+}
+
+/**
+ * C++ entry point for the loader.  This is called from assembly, with the
+ * read-write root in the first argument.
+ */
+[[noreturn]] extern "C" void rom_loader_entry(void *rwRoot)
+{
+	Capability<void> root{rwRoot};
+
+	Capability<volatile SonataRGBLEDCtrl> rgbled_ctrl =
+    root.cast<volatile SonataRGBLEDCtrl>();
+	rgbled_ctrl.address() = RGBLED_CTRL_ADDRESS;
+	rgbled_ctrl.bounds()  = RGBLED_CTRL_BOUNDS;
+
+  while (1) {
+    rgbled_ctrl->set_rgb(32, 0, 0, 1);
+    rgbled_ctrl->set_rgb(0, 32, 0, 0);
+    rgbled_ctrl->update();
+
+    busy_wait(20000000);
+
+    rgbled_ctrl->set_rgb(0, 32, 0, 1);
+    rgbled_ctrl->set_rgb(0, 0, 32, 0);
+    rgbled_ctrl->update();
+
+    busy_wait(20000000);
+
+    rgbled_ctrl->set_rgb(0, 0, 32, 1);
+    rgbled_ctrl->set_rgb(32, 0, 0, 0);
+    rgbled_ctrl->update();
+
+    busy_wait(20000000);
+
+    rgbled_ctrl->clear();
+
+    busy_wait(20000000);
+  }
+}