test: Add test for new command pci_mps

Adds a test for the new pci_mps command to ensure that it can set the
Maximum Payload Size (MPS) of all devices to 256 bytes in the sandbox
environment. Enables the pci_mps command in the sandbox environment so
that this test can be run.

Signed-off-by: Stephen Carlson <stcarlso@linux.microsoft.com>

test/cmd/Makefile

@@ -14,6 +14,9 @@ obj-$(CONFIG_CMD_FDT) += fdt.o
 obj-$(CONFIG_CONSOLE_TRUETYPE) += font.o
 obj-$(CONFIG_CMD_LOADM) += loadm.o
 obj-$(CONFIG_CMD_MEM_SEARCH) += mem_search.o
+ifdef CONFIG_CMD_PCI
+obj-$(CONFIG_CMD_PCI_MPS) += pci_mps.o
+endif
 obj-$(CONFIG_CMD_PINMUX) += pinmux.o
 obj-$(CONFIG_CMD_PWM) += pwm.o
 obj-$(CONFIG_CMD_SEAMA) += seama.o

test/cmd/pci_mps.c

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Tests that the PCI Maximum Payload Size (MPS) command can set the sandbox
+ * PCI Express device to safe mode and determine the correct payload size.
+ *
+ * Copyright 2023 Microsoft
+ * Written by Stephen Carlson <stcarlso@linux.microsoft.com>
+ */
+
+#include <common.h>
+#include <console.h>
+#include <test/suites.h>
+#include <test/ut.h>
+
+#define PCI_MPS_TEST(_name, _flags) UNIT_TEST(_name, _flags, pci_mps_test)
+
+/* Test "pci_mps" command in safe "s" mode */
+static int test_pci_mps_safe(struct unit_test_state *uts)
+{
+	/* Enumerate PCI Express first */
+	ut_assertok(run_command("pci e", 0));
+	ut_assert_console_end();
+
+	/* Test pci_mps s */
+	ut_assertok(run_command("pci_mps s", 0));
+	ut_assert_nextline("Setting MPS of all devices to 256B");
+	ut_assert_console_end();
+
+	return 0;
+}
+
+PCI_MPS_TEST(test_pci_mps_safe, UT_TESTF_CONSOLE_REC);
+
+int do_ut_pci_mps(struct cmd_tbl *cmdtp, int flag, int argc,
+		  char * const argv[])
+{
+	struct unit_test *tests = UNIT_TEST_SUITE_START(pci_mps_test);
+	const int n = UNIT_TEST_SUITE_COUNT(pci_mps_test);
+
+	return cmd_ut_category("cmd_pci_mps", "pci_mps_test_", tests, n,
+			       argc, argv);
+}