libnvdimm: control character device and nvdimm_bus sysfs attributes

The control device for a nvdimm_bus is registered as an "nd" class
device.  The expectation is that there will usually only be one "nd" bus
registered under /sys/class/nd.  However, we allow for the possibility
of multiple buses and they will listed in discovery order as
ndctl0...ndctlN.  This character device hosts the ioctl for passing
control messages.  The initial command set has a 1:1 correlation with
the commands listed in the by the "NFIT DSM Example" document [1], but
this scheme is extensible to future command sets.

Note, nd_ioctl() and the backing ->ndctl() implementation are defined in
a subsequent patch.  This is simply the initial registrations and sysfs
attributes.

[1]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf

Cc: Neil Brown <neilb@suse.de>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: <linux-acpi@vger.kernel.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 291b2fdcd96b..0b0ff2423161 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -17,7 +17,13 @@
 
 struct nvdimm_bus {
 	struct nvdimm_bus_descriptor *nd_desc;
+	struct list_head list;
 	struct device dev;
 	int id;
 };
+
+int __init nvdimm_bus_init(void);
+void __exit nvdimm_bus_exit(void);
+int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);
+void nvdimm_bus_destroy_ndctl(struct nvdimm_bus *nvdimm_bus);
 #endif /* __ND_CORE_H__ */