of: Add device tree selftests

Add some runtime test cases for the library of device tree parsing functions.

v2: - Add testcase for phandle with 0 args
    - Don't run testcases if testcase data isn't present in device tree

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

3 files changed, 149 insertions, 0 deletions

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index cac63c9f49ae..268163dd71c7 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -15,6 +15,15 @@ config PROC_DEVICETREE
           an image of the device tree that the kernel copies from Open
           Firmware or other boot firmware. If unsure, say Y here.
 
+config OF_SELFTEST
+        bool "Device Tree Runtime self tests"
+        help
+          This option builds in test cases for the device tree infrastructure
+          that are executed one at boot time, and the results dumped to the
+          console.
+
+          If unsure, say N here, but this option is safe to enable.
+
 config OF_FLATTREE
         bool
         select DTC
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index dccb1176be57..a73f5a51ff4c 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_OF_GPIO)   += gpio.o
 obj-$(CONFIG_OF_I2C)    += of_i2c.o
 obj-$(CONFIG_OF_NET)    += of_net.o
 obj-$(CONFIG_OF_SPI)    += of_spi.o
+obj-$(CONFIG_OF_SELFTEST) += selftest.o
 obj-$(CONFIG_OF_MDIO)   += of_mdio.o
 obj-$(CONFIG_OF_PCI)    += of_pci.o
 obj-$(CONFIG_OF_PCI_IRQ)  += of_pci_irq.o
diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
new file mode 100644
index 000000000000..9d2b4803a9d6
--- /dev/null
+++ b/drivers/of/selftest.c
@@ -0,0 +1,139 @@
+/*
+ * Self tests for device tree subsystem
+ */
+
+#define pr_fmt(fmt) "### %s(): " fmt, __func__
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+
+static bool selftest_passed = true;
+#define selftest(result, fmt, ...) { \
+        selftest_passed &= (result); \
+        if (!(result)) \
+                pr_err("FAIL %s:%i " fmt, __FILE__, __LINE__, ##__VA_ARGS__); \
+}
+
+static void __init of_selftest_parse_phandle_with_args(void)
+{
+        struct device_node *np;
+        struct of_phandle_args args;
+        int rc, i;
+        bool passed_all = true;
+
+        pr_info("start\n");
+        np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
+        if (!np) {
+                pr_err("missing testcase data\n");
+                return;
+        }
+
+        for (i = 0; i < 7; i++) {
+                bool passed = true;
+                rc = of_parse_phandle_with_args(np, "phandle-list",
+                                                "#phandle-cells", i, &args);
+
+                /* Test the values from tests-phandle.dtsi */
+                switch (i) {
+                case 0:
+                        passed &= !rc;
+                        passed &= (args.args_count == 1);
+                        passed &= (args.args[0] == (i + 1));
+                        break;
+                case 1:
+                        passed &= !rc;
+                        passed &= (args.args_count == 2);
+                        passed &= (args.args[0] == (i + 1));
+                        passed &= (args.args[1] == 0);
+                        break;
+                case 2:
+                        passed &= (rc == -ENOENT);
+                        break;
+                case 3:
+                        passed &= !rc;
+                        passed &= (args.args_count == 3);
+                        passed &= (args.args[0] == (i + 1));
+                        passed &= (args.args[1] == 4);
+                        passed &= (args.args[2] == 3);
+                        break;
+                case 4:
+                        passed &= !rc;
+                        passed &= (args.args_count == 2);
+                        passed &= (args.args[0] == (i + 1));
+                        passed &= (args.args[1] == 100);
+                        break;
+                case 5:
+                        passed &= !rc;
+                        passed &= (args.args_count == 0);
+                        break;
+                case 6:
+                        passed &= !rc;
+                        passed &= (args.args_count == 1);
+                        passed &= (args.args[0] == (i + 1));
+                        break;
+                case 7:
+                        passed &= (rc == -EINVAL);
+                        break;
+                default:
+                        passed = false;
+                }
+
+                if (!passed) {
+                        int j;
+                        pr_err("index %i - data error on node %s rc=%i regs=[",
+                                i, args.np->full_name, rc);
+                        for (j = 0; j < args.args_count; j++)
+                                printk(" %i", args.args[j]);
+                        printk(" ]\n");
+
+                        passed_all = false;
+                }
+        }
+
+        /* Check for missing list property */
+        rc = of_parse_phandle_with_args(np, "phandle-list-missing",
+                                        "#phandle-cells", 0, &args);
+        passed_all &= (rc == -EINVAL);
+
+        /* Check for missing cells property */
+        rc = of_parse_phandle_with_args(np, "phandle-list",
+                                        "#phandle-cells-missing", 0, &args);
+        passed_all &= (rc == -EINVAL);
+
+        /* Check for bad phandle in list */
+        rc = of_parse_phandle_with_args(np, "phandle-list-bad-phandle",
+                                        "#phandle-cells", 0, &args);
+        passed_all &= (rc == -EINVAL);
+
+        /* Check for incorrectly formed argument list */
+        rc = of_parse_phandle_with_args(np, "phandle-list-bad-args",
+                                        "#phandle-cells", 1, &args);
+        passed_all &= (rc == -EINVAL);
+
+        pr_info("end - %s\n", passed_all ? "PASS" : "FAIL");
+}
+
+static int __init of_selftest(void)
+{
+        struct device_node *np;
+
+        np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
+        if (!np) {
+                pr_info("No testcase data in device tree; not running tests\n");
+                return 0;
+        }
+        of_node_put(np);
+
+        pr_info("start of selftest - you will see error messages\n");
+        of_selftest_parse_phandle_with_args();
+        pr_info("end of selftest - %s\n", selftest_passed ? "PASS" : "FAIL");
+        return 0;
+}
+late_initcall(of_selftest);