tools/testing/nvdimm: test get_config_size DSM failures

Add an nfit_test specific attribute for gating whether a get_config_size
DSM, or any DSM for that matter, succeeds or fails.  The get_config_size
DSM is initial motivation since that is the first command libnvdimm core
issues to determine the state of the namespace label area.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

tools/testing/nvdimm/test/nfit.c

@@ -132,6 +132,8 @@ static u32 handle[NUM_DCR] = {
 	[4] = NFIT_DIMM_HANDLE(0, 1, 0, 0, 0),
 };
 
+static unsigned long dimm_fail_cmd_flags[NUM_DCR];
+
 struct nfit_test {
 	struct acpi_nfit_desc acpi_desc;
 	struct platform_device pdev;
@@ -414,6 +416,9 @@ static int nfit_test_ctl(struct nvdimm_bus_descriptor *nd_desc,
 		if (i >= ARRAY_SIZE(handle))
 			return -ENXIO;
 
+		if ((1 << func) & dimm_fail_cmd_flags[i])
+			return -EIO;
+
 		switch (func) {
 		case ND_CMD_GET_CONFIG_SIZE:
 			rc = nfit_test_cmd_get_config_size(buf, buf_len);
@@ -582,6 +587,74 @@ static void put_dimms(void *data)
 
 static struct class *nfit_test_dimm;
 
+static int dimm_name_to_id(struct device *dev)
+{
+	int dimm;
+
+	if (sscanf(dev_name(dev), "test_dimm%d", &dimm) != 1
+			|| dimm >= NUM_DCR || dimm < 0)
+		return -ENXIO;
+	return dimm;
+}
+
+
+static ssize_t handle_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	int dimm = dimm_name_to_id(dev);
+
+	if (dimm < 0)
+		return dimm;
+
+	return sprintf(buf, "%#x", handle[dimm]);
+}
+DEVICE_ATTR_RO(handle);
+
+static ssize_t fail_cmd_show(struct device *dev, struct device_attribute *attr,
+		char *buf)
+{
+	int dimm = dimm_name_to_id(dev);
+
+	if (dimm < 0)
+		return dimm;
+
+	return sprintf(buf, "%#lx\n", dimm_fail_cmd_flags[dimm]);
+}
+
+static ssize_t fail_cmd_store(struct device *dev, struct device_attribute *attr,
+		const char *buf, size_t size)
+{
+	int dimm = dimm_name_to_id(dev);
+	unsigned long val;
+	ssize_t rc;
+
+	if (dimm < 0)
+		return dimm;
+
+	rc = kstrtol(buf, 0, &val);
+	if (rc)
+		return rc;
+
+	dimm_fail_cmd_flags[dimm] = val;
+	return size;
+}
+static DEVICE_ATTR_RW(fail_cmd);
+
+static struct attribute *nfit_test_dimm_attributes[] = {
+	&dev_attr_fail_cmd.attr,
+	&dev_attr_handle.attr,
+	NULL,
+};
+
+static struct attribute_group nfit_test_dimm_attribute_group = {
+	.attrs = nfit_test_dimm_attributes,
+};
+
+static const struct attribute_group *nfit_test_dimm_attribute_groups[] = {
+	&nfit_test_dimm_attribute_group,
+	NULL,
+};
+
 static int nfit_test0_alloc(struct nfit_test *t)
 {
 	size_t nfit_size = sizeof(struct acpi_nfit_system_address) * NUM_SPA
@@ -640,8 +713,10 @@ static int nfit_test0_alloc(struct nfit_test *t)
 	if (devm_add_action_or_reset(&t->pdev.dev, put_dimms, t->dimm_dev))
 		return -ENOMEM;
 	for (i = 0; i < NUM_DCR; i++) {
-		t->dimm_dev[i] = device_create(nfit_test_dimm, &t->pdev.dev, 0,
-				NULL, "test_dimm%d", i);
+		t->dimm_dev[i] = device_create_with_groups(nfit_test_dimm,
+				&t->pdev.dev, 0, NULL,
+				nfit_test_dimm_attribute_groups,
+				"test_dimm%d", i);
 		if (!t->dimm_dev[i])
 			return -ENOMEM;
 	}