libnvdimm: infrastructure for btt devices

NVDIMM namespaces, in addition to accepting "struct bio" based requests,
also have the capability to perform byte-aligned accesses.  By default
only the bio/block interface is used.  However, if another driver can
make effective use of the byte-aligned capability it can claim namespace
interface and use the byte-aligned ->rw_bytes() interface.

The BTT driver is the initial first consumer of this mechanism to allow
adding atomic sector update semantics to a pmem or blk namespace.  This
patch is the sysfs infrastructure to allow configuring a BTT instance
for a namespace.  Enabling that BTT and performing i/o is in a
subsequent patch.

Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index bfa849617358..d13eccbb67e9 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -19,6 +19,10 @@
 #include <linux/types.h>
 #include "label.h"
 
+enum {
+	SECTOR_SHIFT = 9,
+};
+
 struct nvdimm_drvdata {
 	struct device *dev;
 	int nsindex_size;
@@ -74,7 +78,9 @@ static inline struct nd_namespace_index *to_next_namespace_index(
 struct nd_region {
 	struct device dev;
 	struct ida ns_ida;
+	struct ida btt_ida;
 	struct device *ns_seed;
+	struct device *btt_seed;
 	u16 ndr_mappings;
 	u64 ndr_size;
 	u64 ndr_start;
@@ -94,6 +100,14 @@ static inline unsigned nd_inc_seq(unsigned seq)
 	return next[seq & 3];
 }
 
+struct nd_btt {
+	struct device dev;
+	struct nd_namespace_common *ndns;
+	unsigned long lbasize;
+	u8 *uuid;
+	int id;
+};
+
 enum nd_async_mode {
 	ND_SYNC,
 	ND_ASYNC,
@@ -118,6 +132,30 @@ int nvdimm_init_nsarea(struct nvdimm_drvdata *ndd);
 int nvdimm_init_config_data(struct nvdimm_drvdata *ndd);
 int nvdimm_set_config_data(struct nvdimm_drvdata *ndd, size_t offset,
 		void *buf, size_t len);
+struct nd_btt *to_nd_btt(struct device *dev);
+struct btt_sb;
+u64 nd_btt_sb_checksum(struct btt_sb *btt_sb);
+#if IS_ENABLED(CONFIG_BTT)
+int nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata);
+bool is_nd_btt(struct device *dev);
+struct device *nd_btt_create(struct nd_region *nd_region);
+#else
+static inline nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata)
+{
+	return -ENODEV;
+}
+
+static inline bool is_nd_btt(struct device *dev)
+{
+	return false;
+}
+
+static inline struct device *nd_btt_create(struct nd_region *nd_region)
+{
+	return NULL;
+}
+
+#endif
 struct nd_region *to_nd_region(struct device *dev);
 int nd_region_to_nstype(struct nd_region *nd_region);
 int nd_region_register_namespaces(struct nd_region *nd_region, int *err);
@@ -132,4 +170,6 @@ void nvdimm_free_dpa(struct nvdimm_drvdata *ndd, struct resource *res);
 struct resource *nvdimm_allocate_dpa(struct nvdimm_drvdata *ndd,
 		struct nd_label_id *label_id, resource_size_t start,
 		resource_size_t n);
+resource_size_t nvdimm_namespace_capacity(struct nd_namespace_common *ndns);
+struct nd_namespace_common *nvdimm_namespace_common_probe(struct device *dev);
 #endif /* __ND_H__ */