libnvdimm: support for legacy (non-aliasing) nvdimms

The libnvdimm region driver is an intermediary driver that translates
non-volatile "region"s into "namespace" sub-devices that are surfaced by
persistent memory block-device drivers (PMEM and BLK).

ACPI 6 introduces the concept that a given nvdimm may simultaneously
offer multiple access modes to its media through direct PMEM load/store
access, or windowed BLK mode.  Existing nvdimms mostly implement a PMEM
interface, some offer a BLK-like mode, but never both as ACPI 6 defines.
If an nvdimm is single interfaced, then there is no need for dimm
metadata labels.  For these devices we can take the region boundaries
directly to create a child namespace device (nd_namespace_io).

Acked-by: Christoph Hellwig <hch@lst.de>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 111 insertions, 0 deletions

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
new file mode 100644
index 000000000000..4f653d1e61ad
--- /dev/null
+++ b/drivers/nvdimm/namespace_devs.c
@@ -0,0 +1,111 @@
+/*
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/nd.h>
+#include "nd.h"
+
+static void namespace_io_release(struct device *dev)
+{
+	struct nd_namespace_io *nsio = to_nd_namespace_io(dev);
+
+	kfree(nsio);
+}
+
+static struct device_type namespace_io_device_type = {
+	.name = "nd_namespace_io",
+	.release = namespace_io_release,
+};
+
+static ssize_t nstype_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nd_region *nd_region = to_nd_region(dev->parent);
+
+	return sprintf(buf, "%d\n", nd_region_to_nstype(nd_region));
+}
+static DEVICE_ATTR_RO(nstype);
+
+static struct attribute *nd_namespace_attributes[] = {
+	&dev_attr_nstype.attr,
+	NULL,
+};
+
+static struct attribute_group nd_namespace_attribute_group = {
+	.attrs = nd_namespace_attributes,
+};
+
+static const struct attribute_group *nd_namespace_attribute_groups[] = {
+	&nd_device_attribute_group,
+	&nd_namespace_attribute_group,
+	NULL,
+};
+
+static struct device **create_namespace_io(struct nd_region *nd_region)
+{
+	struct nd_namespace_io *nsio;
+	struct device *dev, **devs;
+	struct resource *res;
+
+	nsio = kzalloc(sizeof(*nsio), GFP_KERNEL);
+	if (!nsio)
+		return NULL;
+
+	devs = kcalloc(2, sizeof(struct device *), GFP_KERNEL);
+	if (!devs) {
+		kfree(nsio);
+		return NULL;
+	}
+
+	dev = &nsio->dev;
+	dev->type = &namespace_io_device_type;
+	dev->parent = &nd_region->dev;
+	res = &nsio->res;
+	res->name = dev_name(&nd_region->dev);
+	res->flags = IORESOURCE_MEM;
+	res->start = nd_region->ndr_start;
+	res->end = res->start + nd_region->ndr_size - 1;
+
+	devs[0] = dev;
+	return devs;
+}
+
+int nd_region_register_namespaces(struct nd_region *nd_region, int *err)
+{
+	struct device **devs = NULL;
+	int i;
+
+	*err = 0;
+	switch (nd_region_to_nstype(nd_region)) {
+	case ND_DEVICE_NAMESPACE_IO:
+		devs = create_namespace_io(nd_region);
+		break;
+	default:
+		break;
+	}
+
+	if (!devs)
+		return -ENODEV;
+
+	for (i = 0; devs[i]; i++) {
+		struct device *dev = devs[i];
+
+		dev_set_name(dev, "namespace%d.%d", nd_region->id, i);
+		dev->groups = nd_namespace_attribute_groups;
+		nd_device_register(dev);
+	}
+	kfree(devs);
+
+	return i;
+}