of/overlay: Add overlay unittests

Add unittests for OF overlays.

It tests overlay device addition/removal and whether
the apply revert sequence is correct.

Changes since V1:
* Added local fixups entries.

Signed-off-by: Pantelis Antoniou <[e-mail]>
Signed-off-by: Grant Likely <[e-mail]>

Documentation/devicetree/bindings/unittest.txt

···
+* OF selftest platform device
+
+** selftest
+
+Required properties:
+- compatible: must be "selftest"
+
+All other properties are optional.
+
+Example:
+	selftest {
+		compatible = "selftest";
+		status = "okay";
+	};

drivers/of/unittest-data/testcases.dts

···
 #include "tests-interrupts.dtsi"
 #include "tests-match.dtsi"
 #include "tests-platform.dtsi"
+#include "tests-overlay.dtsi"
 
 /*
  * phandle fixup data - generated by dtc patches that aren't upstream.
···
 		};
 		testcase-device2 {
 			interrupt-parent = <0x00000000>;
+		};
+		overlay2 {
+			fragment@0 {
+				target = <0x00000000>;
+			};
+		};
+		overlay3 {
+			fragment@0 {
+				target = <0x00000000>;
+			};
+		};
+		overlay4 {
+			fragment@0 {
+				target = <0x00000000>;
+			};
 		};
 	};
 }; };

drivers/of/unittest-data/tests-overlay.dtsi

···
+
+/ {
+	testcase-data {
+		overlay-node {
+
+			/* test bus */
+			selftestbus: test-bus {
+				compatible = "simple-bus";
+				#address-cells = <1>;
+				#size-cells = <0>;
+
+				selftest100: test-selftest100 {
+					compatible = "selftest";
+					status = "okay";
+					reg = <100>;
+				};
+
+				selftest101: test-selftest101 {
+					compatible = "selftest";
+					status = "disabled";
+					reg = <101>;
+				};
+
+				selftest0: test-selftest0 {
+					compatible = "selftest";
+					status = "disabled";
+					reg = <0>;
+				};
+
+				selftest1: test-selftest1 {
+					compatible = "selftest";
+					status = "okay";
+					reg = <1>;
+				};
+
+				selftest2: test-selftest2 {
+					compatible = "selftest";
+					status = "disabled";
+					reg = <2>;
+				};
+
+				selftest3: test-selftest3 {
+					compatible = "selftest";
+					status = "okay";
+					reg = <3>;
+				};
+
+				selftest5: test-selftest5 {
+					compatible = "selftest";
+					status = "disabled";
+					reg = <5>;
+				};
+
+				selftest6: test-selftest6 {
+					compatible = "selftest";
+					status = "disabled";
+					reg = <6>;
+				};
+
+				selftest7: test-selftest7 {
+					compatible = "selftest";
+					status = "disabled";
+					reg = <7>;
+				};
+
+				selftest8: test-selftest8 {
+					compatible = "selftest";
+					status = "disabled";
+					reg = <8>;
+				};
+			};
+		};
+
+		/* test enable using absolute target path */
+		overlay0 {
+			fragment@0 {
+				target-path = "/testcase-data/overlay-node/test-bus/test-selftest0";
+				__overlay__ {
+					status = "okay";
+				};
+			};
+		};
+
+		/* test disable using absolute target path */
+		overlay1 {
+			fragment@0 {
+				target-path = "/testcase-data/overlay-node/test-bus/test-selftest1";
+				__overlay__ {
+					status = "disabled";
+				};
+			};
+		};
+
+		/* test enable using label */
+		overlay2 {
+			fragment@0 {
+				target = <&selftest2>;
+				__overlay__ {
+					status = "okay";
+				};
+			};
+		};
+
+		/* test disable using label */
+		overlay3 {
+			fragment@0 {
+				target = <&selftest3>;
+				__overlay__ {
+					status = "disabled";
+				};
+			};
+		};
+
+		/* test insertion of a full node */
+		overlay4 {
+			fragment@0 {
+				target = <&selftestbus>;
+				__overlay__ {
+
+					/* suppress DTC warning */
+					#address-cells = <1>;
+					#size-cells = <0>;
+
+					test-selftest4 {
+						compatible = "selftest";
+						status = "okay";
+						reg = <4>;
+					};
+				};
+			};
+		};
+
+		/* test overlay apply revert */
+		overlay5 {
+			fragment@0 {
+				target-path = "/testcase-data/overlay-node/test-bus/test-selftest5";
+				__overlay__ {
+					status = "okay";
+				};
+			};
+		};
+
+		/* test overlays application and removal in sequence */
+		overlay6 {
+			fragment@0 {
+				target-path = "/testcase-data/overlay-node/test-bus/test-selftest6";
+				__overlay__ {
+					status = "okay";
+				};
+			};
+		};
+		overlay7 {
+			fragment@0 {
+				target-path = "/testcase-data/overlay-node/test-bus/test-selftest7";
+				__overlay__ {
+					status = "okay";
+				};
+			};
+		};
+
+		/* test overlays application and removal in bad sequence */
+		overlay8 {
+			fragment@0 {
+				target-path = "/testcase-data/overlay-node/test-bus/test-selftest8";
+				__overlay__ {
+					status = "okay";
+				};
+			};
+		};
+		overlay9 {
+			fragment@0 {
+				target-path = "/testcase-data/overlay-node/test-bus/test-selftest8";
+				__overlay__ {
+					property-foo = "bar";
+				};
+			};
+		};
+
+	};
+};

drivers/of/unittest.c

···
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
 
 #include "of_private.h"
 
···
 	}
 }
 
+#ifdef CONFIG_OF_OVERLAY
+
+static int selftest_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+
+	if (np == NULL) {
+		dev_err(dev, "No OF data for device\n");
+		return -EINVAL;
+
+	}
+
+	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	return 0;
+}
+
+static int selftest_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+
+	dev_dbg(dev, "%s for node @%s\n", __func__, np->full_name);
+	return 0;
+}
+
+static struct of_device_id selftest_match[] = {
+	{ .compatible = "selftest", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, altera_jtaguart_match);
+
+static struct platform_driver selftest_driver = {
+	.probe			= selftest_probe,
+	.remove			= selftest_remove,
+	.driver = {
+		.name		= "selftest",
+		.owner		= THIS_MODULE,
+		.of_match_table	= of_match_ptr(selftest_match),
+	},
+};
+
+/* get the platform device instantiated at the path */
+static struct platform_device *of_path_to_platform_device(const char *path)
+{
+	struct device_node *np;
+	struct platform_device *pdev;
+
+	np = of_find_node_by_path(path);
+	if (np == NULL)
+		return NULL;
+
+	pdev = of_find_device_by_node(np);
+	of_node_put(np);
+
+	return pdev;
+}
+
+/* find out if a platform device exists at that path */
+static int of_path_platform_device_exists(const char *path)
+{
+	struct platform_device *pdev;
+
+	pdev = of_path_to_platform_device(path);
+	platform_device_put(pdev);
+	return pdev != NULL;
+}
+
+static const char *selftest_path(int nr)
+{
+	static char buf[256];
+
+	snprintf(buf, sizeof(buf) - 1,
+		"/testcase-data/overlay-node/test-bus/test-selftest%d", nr);
+	buf[sizeof(buf) - 1] = '\0';
+
+	return buf;
+}
+
+static const char *overlay_path(int nr)
+{
+	static char buf[256];
+
+	snprintf(buf, sizeof(buf) - 1,
+		"/testcase-data/overlay%d", nr);
+	buf[sizeof(buf) - 1] = '\0';
+
+	return buf;
+}
+
+static const char *bus_path = "/testcase-data/overlay-node/test-bus";
+
+static int of_selftest_apply_overlay(int selftest_nr, int overlay_nr,
+		int *overlay_id)
+{
+	struct device_node *np = NULL;
+	int ret, id = -1;
+
+	np = of_find_node_by_path(overlay_path(overlay_nr));
+	if (np == NULL) {
+		selftest(0, "could not find overlay node @\"%s\"\n",
+				overlay_path(overlay_nr));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = of_overlay_create(np);
+	if (ret < 0) {
+		selftest(0, "could not create overlay from \"%s\"\n",
+				overlay_path(overlay_nr));
+		goto out;
+	}
+	id = ret;
+
+	ret = 0;
+
+out:
+	of_node_put(np);
+
+	if (overlay_id)
+		*overlay_id = id;
+
+	return ret;
+}
+
+/* apply an overlay while checking before and after states */
+static int of_selftest_apply_overlay_check(int overlay_nr, int selftest_nr,
+		int before, int after)
+{
+	int ret;
+
+	/* selftest device must not be in before state */
+	if (of_path_platform_device_exists(selftest_path(selftest_nr))
+			!= before) {
+		selftest(0, "overlay @\"%s\" with device @\"%s\" %s\n",
+				overlay_path(overlay_nr),
+				selftest_path(selftest_nr),
+				!before ? "enabled" : "disabled");
+		return -EINVAL;
+	}
+
+	ret = of_selftest_apply_overlay(overlay_nr, selftest_nr, NULL);
+	if (ret != 0) {
+		/* of_selftest_apply_overlay already called selftest() */
+		return ret;
+	}
+
+	/* selftest device must be to set to after state */
+	if (of_path_platform_device_exists(selftest_path(selftest_nr))
+			!= after) {
+		selftest(0, "overlay @\"%s\" failed to create @\"%s\" %s\n",
+				overlay_path(overlay_nr),
+				selftest_path(selftest_nr),
+				!after ? "enabled" : "disabled");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* apply an overlay and then revert it while checking before, after states */
+static int of_selftest_apply_revert_overlay_check(int overlay_nr,
+		int selftest_nr, int before, int after)
+{
+	int ret, ov_id;
+
+	/* selftest device must be in before state */
+	if (of_path_platform_device_exists(selftest_path(selftest_nr))
+			!= before) {
+		selftest(0, "overlay @\"%s\" with device @\"%s\" %s\n",
+				overlay_path(overlay_nr),
+				selftest_path(selftest_nr),
+				!before ? "enabled" : "disabled");
+		return -EINVAL;
+	}
+
+	/* apply the overlay */
+	ret = of_selftest_apply_overlay(overlay_nr, selftest_nr, &ov_id);
+	if (ret != 0) {
+		/* of_selftest_apply_overlay already called selftest() */
+		return ret;
+	}
+
+	/* selftest device must be in after state */
+	if (of_path_platform_device_exists(selftest_path(selftest_nr))
+			!= after) {
+		selftest(0, "overlay @\"%s\" failed to create @\"%s\" %s\n",
+				overlay_path(overlay_nr),
+				selftest_path(selftest_nr),
+				!after ? "enabled" : "disabled");
+		return -EINVAL;
+	}
+
+	ret = of_overlay_destroy(ov_id);
+	if (ret != 0) {
+		selftest(0, "overlay @\"%s\" failed to be destroyed @\"%s\"\n",
+				overlay_path(overlay_nr),
+				selftest_path(selftest_nr));
+		return ret;
+	}
+
+	/* selftest device must be again in before state */
+	if (of_path_platform_device_exists(selftest_path(selftest_nr))
+			!= before) {
+		selftest(0, "overlay @\"%s\" with device @\"%s\" %s\n",
+				overlay_path(overlay_nr),
+				selftest_path(selftest_nr),
+				!before ? "enabled" : "disabled");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* test activation of device */
+static void of_selftest_overlay_0(void)
+{
+	int ret;
+
+	/* device should enable */
+	ret = of_selftest_apply_overlay_check(0, 0, 0, 1);
+	if (ret != 0)
+		return;
+
+	selftest(1, "overlay test %d passed\n", 0);
+}
+
+/* test deactivation of device */
+static void of_selftest_overlay_1(void)
+{
+	int ret;
+
+	/* device should disable */
+	ret = of_selftest_apply_overlay_check(1, 1, 1, 0);
+	if (ret != 0)
+		return;
+
+	selftest(1, "overlay test %d passed\n", 1);
+}
+
+/* test activation of device */
+static void of_selftest_overlay_2(void)
+{
+	int ret;
+
+	/* device should enable */
+	ret = of_selftest_apply_overlay_check(2, 2, 0, 1);
+	if (ret != 0)
+		return;
+
+	selftest(1, "overlay test %d passed\n", 2);
+}
+
+/* test deactivation of device */
+static void of_selftest_overlay_3(void)
+{
+	int ret;
+
+	/* device should disable */
+	ret = of_selftest_apply_overlay_check(3, 3, 1, 0);
+	if (ret != 0)
+		return;
+
+	selftest(1, "overlay test %d passed\n", 3);
+}
+
+/* test activation of a full device node */
+static void of_selftest_overlay_4(void)
+{
+	int ret;
+
+	/* device should disable */
+	ret = of_selftest_apply_overlay_check(4, 4, 0, 1);
+	if (ret != 0)
+		return;
+
+	selftest(1, "overlay test %d passed\n", 4);
+}
+
+/* test overlay apply/revert sequence */
+static void of_selftest_overlay_5(void)
+{
+	int ret;
+
+	/* device should disable */
+	ret = of_selftest_apply_revert_overlay_check(5, 5, 0, 1);
+	if (ret != 0)
+		return;
+
+	selftest(1, "overlay test %d passed\n", 5);
+}
+
+/* test overlay application in sequence */
+static void of_selftest_overlay_6(void)
+{
+	struct device_node *np;
+	int ret, i, ov_id[2];
+	int overlay_nr = 6, selftest_nr = 6;
+	int before = 0, after = 1;
+
+	/* selftest device must be in before state */
+	for (i = 0; i < 2; i++) {
+		if (of_path_platform_device_exists(
+					selftest_path(selftest_nr + i))
+				!= before) {
+			selftest(0, "overlay @\"%s\" with device @\"%s\" %s\n",
+					overlay_path(overlay_nr + i),
+					selftest_path(selftest_nr + i),
+					!before ? "enabled" : "disabled");
+			return;
+		}
+	}
+
+	/* apply the overlays */
+	for (i = 0; i < 2; i++) {
+
+		np = of_find_node_by_path(overlay_path(overlay_nr + i));
+		if (np == NULL) {
+			selftest(0, "could not find overlay node @\"%s\"\n",
+					overlay_path(overlay_nr + i));
+			return;
+		}
+
+		ret = of_overlay_create(np);
+		if (ret < 0)  {
+			selftest(0, "could not create overlay from \"%s\"\n",
+					overlay_path(overlay_nr + i));
+			return;
+		}
+		ov_id[i] = ret;
+	}
+
+	for (i = 0; i < 2; i++) {
+		/* selftest device must be in after state */
+		if (of_path_platform_device_exists(
+					selftest_path(selftest_nr + i))
+				!= after) {
+			selftest(0, "overlay @\"%s\" failed @\"%s\" %s\n",
+					overlay_path(overlay_nr + i),
+					selftest_path(selftest_nr + i),
+					!after ? "enabled" : "disabled");
+			return;
+		}
+	}
+
+	for (i = 1; i >= 0; i--) {
+		ret = of_overlay_destroy(ov_id[i]);
+		if (ret != 0) {
+			selftest(0, "overlay @\"%s\" failed destroy @\"%s\"\n",
+					overlay_path(overlay_nr + i),
+					selftest_path(selftest_nr + i));
+			return;
+		}
+	}
+
+	for (i = 0; i < 2; i++) {
+		/* selftest device must be again in before state */
+		if (of_path_platform_device_exists(
+					selftest_path(selftest_nr + i))
+				!= before) {
+			selftest(0, "overlay @\"%s\" with device @\"%s\" %s\n",
+					overlay_path(overlay_nr + i),
+					selftest_path(selftest_nr + i),
+					!before ? "enabled" : "disabled");
+			return;
+		}
+	}
+
+	selftest(1, "overlay test %d passed\n", 6);
+}
+
+/* test overlay application in sequence */
+static void of_selftest_overlay_8(void)
+{
+	struct device_node *np;
+	int ret, i, ov_id[2];
+	int overlay_nr = 8, selftest_nr = 8;
+
+	/* we don't care about device state in this test */
+
+	/* apply the overlays */
+	for (i = 0; i < 2; i++) {
+
+		np = of_find_node_by_path(overlay_path(overlay_nr + i));
+		if (np == NULL) {
+			selftest(0, "could not find overlay node @\"%s\"\n",
+					overlay_path(overlay_nr + i));
+			return;
+		}
+
+		ret = of_overlay_create(np);
+		if (ret < 0)  {
+			selftest(0, "could not create overlay from \"%s\"\n",
+					overlay_path(overlay_nr + i));
+			return;
+		}
+		ov_id[i] = ret;
+	}
+
+	/* now try to remove first overlay (it should fail) */
+	ret = of_overlay_destroy(ov_id[0]);
+	if (ret == 0) {
+		selftest(0, "overlay @\"%s\" was destroyed @\"%s\"\n",
+				overlay_path(overlay_nr + 0),
+				selftest_path(selftest_nr));
+		return;
+	}
+
+	/* removing them in order should work */
+	for (i = 1; i >= 0; i--) {
+		ret = of_overlay_destroy(ov_id[i]);
+		if (ret != 0) {
+			selftest(0, "overlay @\"%s\" not destroyed @\"%s\"\n",
+					overlay_path(overlay_nr + i),
+					selftest_path(selftest_nr));
+			return;
+		}
+	}
+
+	selftest(1, "overlay test %d passed\n", 8);
+}
+
+static void __init of_selftest_overlay(void)
+{
+	struct device_node *bus_np = NULL;
+	int ret;
+
+	ret = platform_driver_register(&selftest_driver);
+	if (ret != 0) {
+		selftest(0, "could not register selftest driver\n");
+		goto out;
+	}
+
+	bus_np = of_find_node_by_path(bus_path);
+	if (bus_np == NULL) {
+		selftest(0, "could not find bus_path \"%s\"\n", bus_path);
+		goto out;
+	}
+
+	ret = of_platform_populate(bus_np, of_default_bus_match_table,
+			NULL, NULL);
+	if (ret != 0) {
+		selftest(0, "could not populate bus @ \"%s\"\n", bus_path);
+		goto out;
+	}
+
+	if (!of_path_platform_device_exists(selftest_path(100))) {
+		selftest(0, "could not find selftest0 @ \"%s\"\n",
+				selftest_path(100));
+		goto out;
+	}
+
+	if (of_path_platform_device_exists(selftest_path(101))) {
+		selftest(0, "selftest1 @ \"%s\" should not exist\n",
+				selftest_path(101));
+		goto out;
+	}
+
+	selftest(1, "basic infrastructure of overlays passed");
+
+	/* tests in sequence */
+	of_selftest_overlay_0();
+	of_selftest_overlay_1();
+	of_selftest_overlay_2();
+	of_selftest_overlay_3();
+	of_selftest_overlay_4();
+	of_selftest_overlay_5();
+	of_selftest_overlay_6();
+	of_selftest_overlay_8();
+
+out:
+	of_node_put(bus_np);
+}
+
+#else
+static inline void __init of_selftest_overlay(void) { }
+#endif
+
 static int __init of_selftest(void)
 {
 	struct device_node *np;
···
 	of_selftest_parse_interrupts_extended();
 	of_selftest_match_node();
 	of_selftest_platform_populate();
+	of_selftest_overlay();
 
 	/* removing selftest data from live tree */
 	selftest_data_remove();