tests/acceptance: Count multiple Tux logos displayed on framebuffer

Add a test that verifies that each core properly displays the Tux
logo on the framebuffer device.

We simply follow the OpenCV "Template Matching with Multiple Objects"
tutorial, replacing Lionel Messi by Tux:
https://docs.opencv.org/4.2.0/d4/dc6/tutorial_py_template_matching.html

When OpenCV and NumPy are installed, this test can be run using:

  $ avocado --show=app,framebuffer \
    run -t cpu:i6400 \
    tests/acceptance/machine_mips_malta.py
  JOB ID     : 54f3d8efd8674f289b8aa01a87f5d70c5814544c
  JOB LOG    : avocado/job-results/job-2020-02-01T20.52-54f3d8e/job.log
   (1/3) tests/acceptance/machine_mips_malta.py:MaltaMachineFramebuffer.test_mips_malta_i6400_framebuffer_logo_1core:
  framebuffer: found Tux at position (x, y) = (0, 0)
  PASS (3.37 s)
   (2/3) tests/acceptance/machine_mips_malta.py:MaltaMachineFramebuffer.test_mips_malta_i6400_framebuffer_logo_7cores:
  framebuffer: found Tux at position (x, y) = (0, 0)
  framebuffer: found Tux at position (x, y) = (88, 0)
  framebuffer: found Tux at position (x, y) = (176, 0)
  framebuffer: found Tux at position (x, y) = (264, 0)
  framebuffer: found Tux at position (x, y) = (352, 0)
  framebuffer: found Tux at position (x, y) = (440, 0)
  framebuffer: found Tux at position (x, y) = (528, 0)
  PASS (5.80 s)
   (3/3) tests/acceptance/machine_mips_malta.py:MaltaMachineFramebuffer.test_mips_malta_i6400_framebuffer_logo_8cores:
  framebuffer: found Tux at position (x, y) = (0, 0)
  framebuffer: found Tux at position (x, y) = (88, 0)
  framebuffer: found Tux at position (x, y) = (176, 0)
  framebuffer: found Tux at position (x, y) = (264, 0)
  framebuffer: found Tux at position (x, y) = (352, 0)
  framebuffer: found Tux at position (x, y) = (440, 0)
  framebuffer: found Tux at position (x, y) = (528, 0)
  framebuffer: found Tux at position (x, y) = (616, 0)
  PASS (6.67 s)
  RESULTS    : PASS 3 | ERROR 0 | FAIL 0 | SKIP 0 | WARN 0 | INTERRUPT 0 | CANCEL 0
  JOB TIME   : 16.79 s

If the AVOCADO_CV2_SCREENDUMP_PNG_PATH environment variable is set, the
test will save the screenshot with matched squares to it.

Test inspired by the following post:
https://www.mips.com/blog/how-to-run-smp-linux-in-qemu-on-a-mips64-release-6-cpu/
Kernel built with the following Docker file:
https://github.com/philmd/qemu-testing-blob/blob/malta_i6400/mips/malta/mips64el/Dockerfile

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200201204751.17810-1-f4bug@amsat.org>

MAINTAINERS

@@ -1005,6 +1005,7 @@ F: hw/mips/mips_malta.c
 F: hw/mips/gt64xxx_pci.c
 F: include/hw/southbridge/piix.h
 F: tests/acceptance/linux_ssh_mips_malta.py
+F: tests/acceptance/machine_mips_malta.py
 
 Mipssim
 M: Aleksandar Markovic <amarkovic@wavecomp.com>

tests/acceptance/machine_mips_malta.py

@@ -0,0 +1,118 @@
+# Functional tests for the MIPS Malta board
+#
+# Copyright (c) Philippe Mathieu-Daudé <f4bug@amsat.org>
+#
+# This work is licensed under the terms of the GNU GPL, version 2 or later.
+# See the COPYING file in the top-level directory.
+#
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+import os
+import gzip
+import logging
+
+from avocado import skipUnless
+from avocado_qemu import Test
+from avocado_qemu import wait_for_console_pattern
+from avocado.utils import archive
+
+
+NUMPY_AVAILABLE = True
+try:
+    import numpy as np
+except ImportError:
+    NUMPY_AVAILABLE = False
+
+CV2_AVAILABLE = True
+try:
+    import cv2
+except ImportError:
+    CV2_AVAILABLE = False
+
+
+@skipUnless(NUMPY_AVAILABLE, 'Python NumPy not installed')
+@skipUnless(CV2_AVAILABLE, 'Python OpenCV not installed')
+class MaltaMachineFramebuffer(Test):
+
+    timeout = 30
+
+    KERNEL_COMMON_COMMAND_LINE = 'printk.time=0 '
+
+    def do_test_i6400_framebuffer_logo(self, cpu_cores_count):
+        """
+        Boot Linux kernel and check Tux logo is displayed on the framebuffer.
+        """
+        screendump_path = os.path.join(self.workdir, 'screendump.pbm')
+
+        kernel_url = ('https://github.com/philmd/qemu-testing-blob/raw/'
+                      'a5966ca4b5/mips/malta/mips64el/'
+                      'vmlinux-4.7.0-rc1.I6400.gz')
+        kernel_hash = '096f50c377ec5072e6a366943324622c312045f6'
+        kernel_path_gz = self.fetch_asset(kernel_url, asset_hash=kernel_hash)
+        kernel_path = self.workdir + "vmlinux"
+        archive.gzip_uncompress(kernel_path_gz, kernel_path)
+
+        tuxlogo_url = ('https://github.com/torvalds/linux/raw/v2.6.12/'
+                       'drivers/video/logo/logo_linux_vga16.ppm')
+        tuxlogo_hash = '3991c2ddbd1ddaecda7601f8aafbcf5b02dc86af'
+        tuxlogo_path = self.fetch_asset(tuxlogo_url, asset_hash=tuxlogo_hash)
+
+        self.vm.set_console()
+        kernel_command_line = (self.KERNEL_COMMON_COMMAND_LINE +
+                               'clocksource=GIC console=tty0 console=ttyS0')
+        self.vm.add_args('-kernel', kernel_path,
+                         '-cpu', 'I6400',
+                         '-smp', '%u' % cpu_cores_count,
+                         '-vga', 'std',
+                         '-append', kernel_command_line)
+        self.vm.launch()
+        framebuffer_ready = 'Console: switching to colour frame buffer device'
+        wait_for_console_pattern(self, framebuffer_ready,
+                                 failure_message='Kernel panic - not syncing')
+        self.vm.command('human-monitor-command', command_line='stop')
+        self.vm.command('human-monitor-command',
+                        command_line='screendump %s' % screendump_path)
+        logger = logging.getLogger('framebuffer')
+
+        match_threshold = 0.95
+        screendump_bgr = cv2.imread(screendump_path, cv2.IMREAD_COLOR)
+        tuxlogo_bgr = cv2.imread(tuxlogo_path, cv2.IMREAD_COLOR)
+        result = cv2.matchTemplate(screendump_bgr, tuxlogo_bgr,
+                                   cv2.TM_CCOEFF_NORMED)
+        loc = np.where(result >= match_threshold)
+        tuxlogo_count = 0
+        h, w = tuxlogo_bgr.shape[:2]
+        debug_png = os.getenv('AVOCADO_CV2_SCREENDUMP_PNG_PATH')
+        for tuxlogo_count, pt in enumerate(zip(*loc[::-1]), start=1):
+            logger.debug('found Tux at position (x, y) = %s', pt)
+            cv2.rectangle(screendump_bgr, pt,
+                          (pt[0] + w, pt[1] + h), (0, 0, 255), 2)
+        if debug_png:
+            cv2.imwrite(debug_png, screendump_bgr)
+        self.assertGreaterEqual(tuxlogo_count, cpu_cores_count)
+
+    def test_mips_malta_i6400_framebuffer_logo_1core(self):
+        """
+        :avocado: tags=arch:mips64el
+        :avocado: tags=machine:malta
+        :avocado: tags=cpu:i6400
+        """
+        self.do_test_i6400_framebuffer_logo(1)
+
+    def test_mips_malta_i6400_framebuffer_logo_7cores(self):
+        """
+        :avocado: tags=arch:mips64el
+        :avocado: tags=machine:malta
+        :avocado: tags=cpu:i6400
+        :avocado: tags=mips:smp
+        """
+        self.do_test_i6400_framebuffer_logo(7)
+
+    def test_mips_malta_i6400_framebuffer_logo_8cores(self):
+        """
+        :avocado: tags=arch:mips64el
+        :avocado: tags=machine:malta
+        :avocado: tags=cpu:i6400
+        :avocado: tags=mips:smp
+        """
+        self.do_test_i6400_framebuffer_logo(8)