libnvdimm, nfit: regions (block-data-window, persistent memory, volatile memory)

A "region" device represents the maximum capacity of a BLK range (mmio
block-data-window(s)), or a PMEM range (DAX-capable persistent memory or
volatile memory), without regard for aliasing.  Aliasing, in the
dimm-local address space (DPA), is resolved by metadata on a dimm to
designate which exclusive interface will access the aliased DPA ranges.
Support for the per-dimm metadata/label arrvies is in a subsequent
patch.

The name format of "region" devices is "regionN" where, like dimms, N is
a global ida index assigned at discovery time.  This id is not reliable
across reboots nor in the presence of hotplug.  Look to attributes of
the region or static id-data of the sub-namespace to generate a
persistent name.  However, if the platform configuration does not change
it is reasonable to expect the same region id to be assigned at the next
boot.

"region"s have 2 generic attributes "size", and "mapping"s where:
- size: the BLK accessible capacity or the span of the
  system physical address range in the case of PMEM.

- mappingN: a tuple describing a dimm's contribution to the region's
  capacity in the format (<nmemX>,<dpa>,<size>).  For a PMEM-region
  there will be at least one mapping per dimm in the interleave set.  For
  a BLK-region there is only "mapping0" listing the starting DPA of the
  BLK-region and the available DPA capacity of that space (matches "size"
  above).

The max number of mappings per "region" is hard coded per the
constraints of sysfs attribute groups.  That said the number of mappings
per region should never exceed the maximum number of possible dimms in
the system.  If the current number turns out to not be enough then the
"mappings" attribute clarifies how many there are supposed to be. "32
should be enough for anybody...".

Cc: Neil Brown <neilb@suse.de>
Cc: <linux-acpi@vger.kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.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, 25 insertions, 0 deletions

diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index d3ebccf4ea8b..39e7e606092a 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -26,11 +26,14 @@ enum {
 	ND_CMD_MAX_ELEM = 4,
 	ND_CMD_MAX_ENVELOPE = 16,
 	ND_CMD_ARS_STATUS_MAX = SZ_4K,
+	ND_MAX_MAPPINGS = 32,
 };
 
 extern struct attribute_group nvdimm_bus_attribute_group;
 extern struct attribute_group nvdimm_attribute_group;
 extern struct attribute_group nd_device_attribute_group;
+extern struct attribute_group nd_region_attribute_group;
+extern struct attribute_group nd_mapping_attribute_group;
 
 struct nvdimm;
 struct nvdimm_bus_descriptor;
@@ -38,6 +41,12 @@ typedef int (*ndctl_fn)(struct nvdimm_bus_descriptor *nd_desc,
 		struct nvdimm *nvdimm, unsigned int cmd, void *buf,
 		unsigned int buf_len);
 
+struct nd_mapping {
+	struct nvdimm *nvdimm;
+	u64 start;
+	u64 size;
+};
+
 struct nvdimm_bus_descriptor {
 	const struct attribute_group **attr_groups;
 	unsigned long dsm_mask;
@@ -52,6 +61,14 @@ struct nd_cmd_desc {
 	int out_sizes[ND_CMD_MAX_ELEM];
 };
 
+struct nd_region_desc {
+	struct resource *res;
+	struct nd_mapping *nd_mapping;
+	u16 num_mappings;
+	const struct attribute_group **attr_groups;
+	void *provider_data;
+};
+
 struct nvdimm_bus;
 struct device;
 struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
@@ -59,9 +76,11 @@ struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
 void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus);
 struct nvdimm_bus *to_nvdimm_bus(struct device *dev);
 struct nvdimm *to_nvdimm(struct device *dev);
+struct nd_region *to_nd_region(struct device *dev);
 struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
 const char *nvdimm_name(struct nvdimm *nvdimm);
 void *nvdimm_provider_data(struct nvdimm *nvdimm);
+void *nd_region_provider_data(struct nd_region *nd_region);
 struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
 		const struct attribute_group **groups, unsigned long flags,
 		unsigned long *dsm_mask);
@@ -73,4 +92,10 @@ u32 nd_cmd_out_size(struct nvdimm *nvdimm, int cmd,
 		const struct nd_cmd_desc *desc, int idx, const u32 *in_field,
 		const u32 *out_field);
 int nvdimm_bus_check_dimm_count(struct nvdimm_bus *nvdimm_bus, int dimm_count);
+struct nd_region *nvdimm_pmem_region_create(struct nvdimm_bus *nvdimm_bus,
+		struct nd_region_desc *ndr_desc);
+struct nd_region *nvdimm_blk_region_create(struct nvdimm_bus *nvdimm_bus,
+		struct nd_region_desc *ndr_desc);
+struct nd_region *nvdimm_volatile_region_create(struct nvdimm_bus *nvdimm_bus,
+		struct nd_region_desc *ndr_desc);
 #endif /* __LIBNVDIMM_H__ */