From: Ross Zwisler <ross.zwis...@linux.intel.com>

The libnd implementation handles allocating dimm address space (DPA)
between PMEM and BLK mode interfaces.  After DPA has been allocated from
a BLK-region to a BLK-namespace the nd_blk driver attaches to handle I/O
as a struct bio based block device. Unlike PMEM, BLK is required to
handle platform specific details like mmio register formats and memory
controller interleave.  For this reason the libnd generic nd_blk driver
calls back into the bus provider to carry out the I/O.

This initial implementation handles the BLK interface defined by the
ACPI 6 NFIT [1] and the NVDIMM DSM Interface Example [2] composed from
DCR (dimm control region), BDW (block data window), IDT (interleave
descriptor) NFIT structures and the hardware register format.
[1]: http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf
[2]: http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf

Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Boaz Harrosh <b...@plexistor.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Jens Axboe <ax...@fb.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Christoph Hellwig <h...@lst.de>
Signed-off-by: Ross Zwisler <ross.zwis...@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
 drivers/acpi/nfit.c               |  442 +++++++++++++++++++++++++++++++++++--
 drivers/acpi/nfit.h               |   50 ++++
 drivers/block/nd/Kconfig          |   13 +
 drivers/block/nd/Makefile         |    3 
 drivers/block/nd/blk.c            |  252 +++++++++++++++++++++
 drivers/block/nd/dimm_devs.c      |    9 +
 drivers/block/nd/namespace_devs.c |   47 ++++
 drivers/block/nd/nd-private.h     |    3 
 drivers/block/nd/nd.h             |   13 +
 drivers/block/nd/region.c         |    8 +
 drivers/block/nd/region_devs.c    |   90 ++++++--
 include/linux/libnd.h             |   17 +
 12 files changed, 909 insertions(+), 38 deletions(-)
 create mode 100644 drivers/block/nd/blk.c

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index a9aca87301c6..c4ce498da9eb 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -13,12 +13,16 @@
 #include <linux/list_sort.h>
 #include <linux/module.h>
 #include <linux/libnd.h>
+#include <linux/mutex.h>
 #include <linux/ndctl.h>
 #include <linux/list.h>
 #include <linux/acpi.h>
 #include <linux/sort.h>
+#include <linux/io.h>
 #include "nfit.h"
 
+#include <asm-generic/io-64-nonatomic-hi-lo.h>
+
 static bool force_enable_dimms;
 module_param(force_enable_dimms, bool, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(force_enable_dimms, "Ignore _STA (ACPI DIMM device) status");
@@ -71,7 +75,7 @@ static int acpi_nfit_ctl(struct nd_bus_descriptor *nd_desc,
 
                if (!adev)
                        return -ENOTTY;
-               dimm_name = dev_name(&adev->dev);
+               dimm_name = nd_dimm_name(nd_dimm);
                cmd_name = nd_dimm_cmd_name(cmd);
                dsm_mask = nfit_mem->dsm_mask;
                desc = nd_cmd_dimm_desc(cmd);
@@ -266,10 +270,20 @@ static void *add_table(struct acpi_nfit_desc *acpi_desc, 
void *table, const void
                                bdw->region_index, bdw->windows);
                break;
        }
-       /* TODO */
-       case ACPI_NFIT_TYPE_INTERLEAVE:
-               dev_dbg(dev, "%s: idt\n", __func__);
+       case ACPI_NFIT_TYPE_INTERLEAVE: {
+               struct nfit_idt *nfit_idt = devm_kzalloc(dev, sizeof(*nfit_idt),
+                               GFP_KERNEL);
+               struct acpi_nfit_interleave *idt = table;
+
+               if (!nfit_idt)
+                       return err;
+               INIT_LIST_HEAD(&nfit_idt->list);
+               nfit_idt->idt = idt;
+               list_add_tail(&nfit_idt->list, &acpi_desc->idts);
+               dev_dbg(dev, "%s: idt index: %d num_lines: %d\n", __func__,
+                               idt->interleave_index, idt->line_count);
                break;
+       }
        case ACPI_NFIT_TYPE_FLUSH_ADDRESS:
                dev_dbg(dev, "%s: flush\n", __func__);
                break;
@@ -321,8 +335,11 @@ static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
                struct nfit_mem *nfit_mem, struct acpi_nfit_system_address *spa)
 {
        u16 dcr_index = __to_nfit_memdev(nfit_mem)->region_index;
+       struct nfit_memdev *nfit_memdev;
        struct nfit_dcr *nfit_dcr;
        struct nfit_bdw *nfit_bdw;
+       struct nfit_idt *nfit_idt;
+       u16 idt_index, range_index;
 
        list_for_each_entry(nfit_dcr, &acpi_desc->dcrs, list) {
                if (nfit_dcr->dcr->region_index != dcr_index)
@@ -355,6 +372,26 @@ static int nfit_mem_add(struct acpi_nfit_desc *acpi_desc,
                return 0;
 
        nfit_mem_find_spa_bdw(acpi_desc, nfit_mem);
+
+       if (!nfit_mem->spa_bdw)
+               return 0;
+
+       range_index = nfit_mem->spa_bdw->range_index;
+       list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
+               if (nfit_memdev->memdev->range_index != range_index ||
+                               nfit_memdev->memdev->region_index != dcr_index)
+                       continue;
+               nfit_mem->memdev_bdw = nfit_memdev->memdev;
+               idt_index = nfit_memdev->memdev->interleave_index;
+               list_for_each_entry(nfit_idt, &acpi_desc->idts, list) {
+                       if (nfit_idt->idt->interleave_index != idt_index)
+                               continue;
+                       nfit_mem->idt_bdw = nfit_idt->idt;
+                       break;
+               }
+               break;
+       }
+
        return 0;
 }
 
@@ -398,9 +435,19 @@ static int nfit_mem_dcr_init(struct acpi_nfit_desc 
*acpi_desc,
                }
 
                if (type == NFIT_SPA_DCR) {
+                       struct nfit_idt *nfit_idt;
+                       u16 idt_index;
+
                        /* multiple dimms may share a SPA when interleaved */
                        nfit_mem->spa_dcr = spa;
                        nfit_mem->memdev_dcr = nfit_memdev->memdev;
+                       idt_index = nfit_memdev->memdev->interleave_index;
+                       list_for_each_entry(nfit_idt, &acpi_desc->idts, list) {
+                               if (nfit_idt->idt->interleave_index != 
idt_index)
+                                       continue;
+                               nfit_mem->idt_dcr = nfit_idt->idt;
+                               break;
+                       }
                } else {
                        /*
                         * A single dimm may belong to multiple SPA-PM
@@ -830,13 +877,362 @@ static int acpi_nfit_init_interleave_set(struct 
acpi_nfit_desc *acpi_desc,
        return 0;
 }
 
+static u64 to_interleave_offset(u64 offset, struct nfit_blk_mmio *mmio)
+{
+       struct acpi_nfit_interleave *idt = mmio->idt;
+       u32 sub_line_offset, line_index, line_offset;
+       u64 line_no, table_skip_count, table_offset;
+
+       line_no = div_u64_rem(offset, mmio->line_size, &sub_line_offset);
+       table_skip_count = div_u64_rem(line_no, mmio->num_lines, &line_index);
+       line_offset = idt->line_offset[line_index]
+               * mmio->line_size;
+       table_offset = table_skip_count * mmio->table_size;
+
+       return mmio->base_offset + line_offset + table_offset + sub_line_offset;
+}
+
+static u64 read_blk_stat(struct nfit_blk *nfit_blk, unsigned int bw)
+{
+       struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
+       u64 offset = nfit_blk->stat_offset + mmio->size * bw;
+
+       if (mmio->num_lines)
+               offset = to_interleave_offset(offset, mmio);
+
+       return readq(mmio->base + offset);
+}
+
+static void write_blk_ctl(struct nfit_blk *nfit_blk, unsigned int bw,
+               resource_size_t dpa, unsigned int len, unsigned int write)
+{
+       u64 cmd, offset;
+       struct nfit_blk_mmio *mmio = &nfit_blk->mmio[DCR];
+
+       enum {
+               BCW_OFFSET_MASK = (1ULL << 48)-1,
+               BCW_LEN_SHIFT = 48,
+               BCW_LEN_MASK = (1ULL << 8) - 1,
+               BCW_CMD_SHIFT = 56,
+       };
+
+       cmd = (dpa >> L1_CACHE_SHIFT) & BCW_OFFSET_MASK;
+       len = len >> L1_CACHE_SHIFT;
+       cmd |= ((u64) len & BCW_LEN_MASK) << BCW_LEN_SHIFT;
+       cmd |= ((u64) write) << BCW_CMD_SHIFT;
+
+       offset = nfit_blk->cmd_offset + mmio->size * bw;
+       if (mmio->num_lines)
+               offset = to_interleave_offset(offset, mmio);
+
+       writeq(cmd, mmio->base + offset);
+       /* FIXME: conditionally perform read-back if mandated by firmware */
+}
+
+static int acpi_nfit_blk_single_io(struct nfit_blk *nfit_blk, void *iobuf,
+               unsigned int len, int write, resource_size_t dpa,
+               unsigned int bw)
+{
+       struct nfit_blk_mmio *mmio = &nfit_blk->mmio[BDW];
+       unsigned int copied = 0;
+       u64 base_offset;
+       int rc;
+
+       base_offset = nfit_blk->bdw_offset + dpa % L1_CACHE_BYTES + bw * 
mmio->size;
+       /* TODO: non-temporal access, flush hints, cache management etc... */
+       write_blk_ctl(nfit_blk, bw, dpa, len, write);
+       while (len) {
+               unsigned int c;
+               u64 offset;
+
+               if (mmio->num_lines) {
+                       u32 line_offset;
+
+                       offset = to_interleave_offset(base_offset + copied,
+                                       mmio);
+                       div_u64_rem(offset, mmio->line_size, &line_offset);
+                       c = min(len, mmio->line_size - line_offset);
+               } else {
+                       offset = base_offset + nfit_blk->bdw_offset;
+                       c = len;
+               }
+
+               if (write)
+                       memcpy(mmio->base + offset, iobuf + copied, c);
+               else
+                       memcpy(iobuf + copied, mmio->base + offset, c);
+
+               copied += c;
+               len -= c;
+       }
+       rc = read_blk_stat(nfit_blk, bw) ? -EIO : 0;
+       return rc;
+}
+
+static int acpi_nfit_blk_region_do_io(struct nd_blk_region *ndbr, void *iobuf,
+               u64 len, int write, resource_size_t dpa)
+{
+       struct nfit_blk *nfit_blk = nd_blk_region_provider_data(ndbr);
+       struct nfit_blk_mmio *mmio = &nfit_blk->mmio[BDW];
+       struct nd_region *nd_region = nfit_blk->nd_region;
+       unsigned int bw, copied = 0;
+       int rc = 0;
+
+       bw = nd_region_acquire_lane(nd_region);
+       while (len) {
+               u64 c = min(len, mmio->size);
+
+               rc = acpi_nfit_blk_single_io(nfit_blk, iobuf + copied, c, write,
+                               dpa + copied, bw);
+               if (rc)
+                       break;
+
+               copied += c;
+               len -= c;
+       }
+       nd_region_release_lane(nd_region, bw);
+
+       return rc;
+}
+
+static void nfit_spa_mapping_release(struct kref *kref)
+{
+       struct nfit_spa_mapping *spa_map = to_spa_map(kref);
+       struct acpi_nfit_system_address *spa = spa_map->spa;
+       struct acpi_nfit_desc *acpi_desc = spa_map->acpi_desc;
+
+       WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
+       dev_dbg(acpi_desc->dev, "%s: SPA%d\n", __func__, spa->range_index);
+       iounmap(spa_map->iomem);
+       release_mem_region(spa->address, spa->length);
+       list_del(&spa_map->list);
+       kfree(spa_map);
+}
+
+static struct nfit_spa_mapping *find_spa_mapping(struct acpi_nfit_desc 
*acpi_desc,
+               struct acpi_nfit_system_address *spa)
+{
+       struct nfit_spa_mapping *spa_map;
+
+       WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
+       list_for_each_entry(spa_map, &acpi_desc->spa_maps, list)
+               if (spa_map->spa == spa)
+                       return spa_map;
+
+       return NULL;
+}
+
+static void nfit_spa_unmap(struct acpi_nfit_desc *acpi_desc,
+               struct acpi_nfit_system_address *spa)
+{
+       struct nfit_spa_mapping *spa_map;
+
+       mutex_lock(&acpi_desc->spa_map_mutex);
+       spa_map = find_spa_mapping(acpi_desc, spa);
+
+       if (spa_map)
+               kref_put(&spa_map->kref, nfit_spa_mapping_release);
+       mutex_unlock(&acpi_desc->spa_map_mutex);
+}
+
+static void *__nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
+               struct acpi_nfit_system_address *spa)
+{
+       resource_size_t start = spa->address;
+       resource_size_t n = spa->length;
+       struct nfit_spa_mapping *spa_map;
+       struct resource *res;
+
+       WARN_ON(!mutex_is_locked(&acpi_desc->spa_map_mutex));
+
+       spa_map = find_spa_mapping(acpi_desc, spa);
+       if (spa_map) {
+               kref_get(&spa_map->kref);
+               return spa_map->iomem;
+       }
+
+       spa_map = kzalloc(sizeof(*spa_map), GFP_KERNEL);
+       if (!spa_map)
+               return NULL;
+
+       INIT_LIST_HEAD(&spa_map->list);
+       spa_map->spa = spa;
+       kref_init(&spa_map->kref);
+       spa_map->acpi_desc = acpi_desc;
+
+       res = request_mem_region(start, n, dev_name(acpi_desc->dev));
+       if (!res)
+               goto err_mem;
+
+       /* TODO: cacheability based on the spa type */
+       spa_map->iomem = ioremap_nocache(start, n);
+       if (!spa_map->iomem)
+               goto err_map;
+
+       list_add_tail(&spa_map->list, &acpi_desc->spa_maps);
+       return spa_map->iomem;
+
+ err_map:
+       release_mem_region(start, n);
+ err_mem:
+       kfree(spa_map);
+       return NULL;
+}
+
+/**
+ * nfit_spa_map - interleave-aware managed-mappings of 
acpi_nfit_system_address ranges
+ * @nd_bus: NFIT-bus that provided the spa table entry
+ * @nfit_spa: spa table to map
+ *
+ * In the case where block-data-window apertures and
+ * dimm-control-regions are interleaved they will end up sharing a
+ * single request_mem_region() + ioremap() for the address range.  In
+ * the style of devm nfit_spa_map() mappings are automatically dropped
+ * when all region devices referencing the same mapping are disabled /
+ * unbound.
+ */
+static void *nfit_spa_map(struct acpi_nfit_desc *acpi_desc,
+               struct acpi_nfit_system_address *spa)
+{
+       struct nfit_spa_mapping *spa_map;
+
+       mutex_lock(&acpi_desc->spa_map_mutex);
+       spa_map = __nfit_spa_map(acpi_desc, spa);
+       mutex_unlock(&acpi_desc->spa_map_mutex);
+
+       return spa_map;
+}
+
+static int nfit_blk_init_interleave(struct nfit_blk_mmio *mmio,
+               struct acpi_nfit_interleave *idt, u16 interleave_ways)
+{
+       if (idt) {
+               mmio->num_lines = idt->line_count;
+               mmio->line_size = idt->line_size;
+               if (interleave_ways == 0)
+                       return -ENXIO;
+               mmio->table_size = mmio->num_lines * interleave_ways
+                       * mmio->line_size;
+       }
+
+       return 0;
+}
+
+static int acpi_nfit_blk_region_enable(struct nd_bus *nd_bus, struct device 
*dev)
+{
+       struct nd_bus_descriptor *nd_desc = to_nd_desc(nd_bus);
+       struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+       struct nd_blk_region *ndbr = to_nd_blk_region(dev);
+       struct nfit_blk_mmio *mmio;
+       struct nfit_blk *nfit_blk;
+       struct nfit_mem *nfit_mem;
+       struct nd_dimm *nd_dimm;
+       int rc;
+
+       nd_dimm = nd_blk_region_to_dimm(ndbr);
+       nfit_mem = nd_dimm_provider_data(nd_dimm);
+       if (!nfit_mem || !nfit_mem->dcr || !nfit_mem->bdw) {
+               dev_dbg(dev, "%s: missing%s%s%s\n", __func__,
+                               nfit_mem ? "" : " nfit_mem",
+                               nfit_mem->dcr ? "" : " dcr",
+                               nfit_mem->bdw ? "" : " bdw");
+               return -ENXIO;
+       }
+
+       nfit_blk = devm_kzalloc(dev, sizeof(*nfit_blk), GFP_KERNEL);
+       if (!nfit_blk)
+               return -ENOMEM;
+       nd_blk_region_set_provider_data(ndbr, nfit_blk);
+       nfit_blk->nd_region = to_nd_region(dev);
+
+       /* map block aperture memory */
+       nfit_blk->bdw_offset = nfit_mem->bdw->offset;
+       mmio = &nfit_blk->mmio[BDW];
+       mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_bdw);
+       if (!mmio->base) {
+               dev_dbg(dev, "%s: %s failed to map bdw\n", __func__,
+                               nd_dimm_name(nd_dimm));
+               return -ENOMEM;
+       }
+       mmio->size = nfit_mem->bdw->size;
+       mmio->base_offset = nfit_mem->memdev_bdw->region_offset;
+       mmio->idt = nfit_mem->idt_bdw;
+       mmio->spa = nfit_mem->spa_bdw;
+       rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_bdw,
+                       nfit_mem->memdev_bdw->interleave_ways);
+       if (rc) {
+               dev_dbg(dev, "%s: %s failed to init bdw interleave\n",
+                               __func__, nd_dimm_name(nd_dimm));
+               return rc;
+       }
+
+       /* map block control memory */
+       nfit_blk->cmd_offset = nfit_mem->dcr->command_offset;
+       nfit_blk->stat_offset = nfit_mem->dcr->status_offset;
+       mmio = &nfit_blk->mmio[DCR];
+       mmio->base = nfit_spa_map(acpi_desc, nfit_mem->spa_dcr);
+       if (!mmio->base) {
+               dev_dbg(dev, "%s: %s failed to map dcr\n", __func__,
+                               nd_dimm_name(nd_dimm));
+               return -ENOMEM;
+       }
+       mmio->size = nfit_mem->dcr->window_size;
+       mmio->base_offset = nfit_mem->memdev_dcr->region_offset;
+       mmio->idt = nfit_mem->idt_dcr;
+       mmio->spa = nfit_mem->spa_dcr;
+       rc = nfit_blk_init_interleave(mmio, nfit_mem->idt_dcr,
+                       nfit_mem->memdev_dcr->interleave_ways);
+       if (rc) {
+               dev_dbg(dev, "%s: %s failed to init dcr interleave\n",
+                               __func__, nd_dimm_name(nd_dimm));
+               return rc;
+       }
+
+       if (mmio->line_size == 0)
+               return 0;
+
+       if ((u32) nfit_blk->cmd_offset % mmio->line_size + 8 > mmio->line_size) 
{
+               dev_dbg(dev, "cmd_offset crosses interleave boundary\n");
+               return -ENXIO;
+       } else if ((u32) nfit_blk->stat_offset % mmio->line_size + 8 > 
mmio->line_size) {
+               dev_dbg(dev, "stat_offset crosses interleave boundary\n");
+               return -ENXIO;
+       }
+
+       return 0;
+}
+
+static void acpi_nfit_blk_region_disable(struct nd_bus *nd_bus,
+               struct device *dev)
+{
+       struct nd_bus_descriptor *nd_desc = to_nd_desc(nd_bus);
+       struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
+       struct nd_blk_region *ndbr = to_nd_blk_region(dev);
+       struct nfit_blk *nfit_blk = nd_blk_region_provider_data(ndbr);
+       int i;
+
+       if (!nfit_blk)
+               return; /* never enabled */
+
+       /* auto-free BLK spa mappings */
+       for (i = 0; i < 2; i++) {
+               struct nfit_blk_mmio *mmio = &nfit_blk->mmio[i];
+
+               if (mmio->base)
+                       nfit_spa_unmap(acpi_desc, mmio->spa);
+       }
+       nd_blk_region_set_provider_data(ndbr, NULL);
+       /* devm will free nfit_blk */
+}
+
 static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
                struct nfit_spa *nfit_spa)
 {
        static struct nd_mapping nd_mappings[ND_MAX_MAPPINGS];
        struct acpi_nfit_system_address *spa = nfit_spa->spa;
+       struct nd_blk_region_desc ndbr_desc;
+       struct nd_region_desc *ndr_desc;
        struct nfit_memdev *nfit_memdev;
-       struct nd_region_desc ndr_desc;
        int spa_type, count = 0, rc;
        struct resource res;
        u16 range_index;
@@ -851,12 +1247,13 @@ static int acpi_nfit_register_region(struct 
acpi_nfit_desc *acpi_desc,
 
        memset(&res, 0, sizeof(res));
        memset(&nd_mappings, 0, sizeof(nd_mappings));
-       memset(&ndr_desc, 0, sizeof(ndr_desc));
+       memset(&ndbr_desc, 0, sizeof(ndr_desc));
        res.start = spa->address;
        res.end = res.start + spa->length - 1;
-       ndr_desc.res = &res;
-       ndr_desc.provider_data = nfit_spa;
-       ndr_desc.attr_groups = acpi_nfit_region_attribute_groups;
+       ndr_desc = &ndbr_desc.ndr_desc;
+       ndr_desc->res = &res;
+       ndr_desc->provider_data = nfit_spa;
+       ndr_desc->attr_groups = acpi_nfit_region_attribute_groups;
        list_for_each_entry(nfit_memdev, &acpi_desc->memdevs, list) {
                struct acpi_nfit_memory_map *memdev = nfit_memdev->memdev;
                struct nd_mapping *nd_mapping;
@@ -892,26 +1289,29 @@ static int acpi_nfit_register_region(struct 
acpi_nfit_desc *acpi_desc,
                        } else {
                                nd_mapping->size = nfit_mem->bdw->capacity;
                                nd_mapping->start = 
nfit_mem->bdw->start_address;
-                               ndr_desc.num_lanes = nfit_mem->bdw->windows;
+                               ndr_desc->num_lanes = nfit_mem->bdw->windows;
                        }
 
-                       ndr_desc.nd_mapping = nd_mapping;
-                       ndr_desc.num_mappings = blk_valid;
-                       if (!nd_blk_region_create(acpi_desc->nd_bus, &ndr_desc))
+                       ndr_desc->nd_mapping = nd_mapping;
+                       ndr_desc->num_mappings = blk_valid;
+                       ndbr_desc.enable = acpi_desc->blk_enable;
+                       ndbr_desc.disable = acpi_desc->blk_disable;
+                       ndbr_desc.do_io = acpi_desc->blk_do_io;
+                       if (!nd_blk_region_create(acpi_desc->nd_bus, ndr_desc))
                                return -ENOMEM;
                }
        }
 
-       ndr_desc.nd_mapping = nd_mappings;
-       ndr_desc.num_mappings = count;
-       rc = acpi_nfit_init_interleave_set(acpi_desc, &ndr_desc, spa);
+       ndr_desc->nd_mapping = nd_mappings;
+       ndr_desc->num_mappings = count;
+       rc = acpi_nfit_init_interleave_set(acpi_desc, ndr_desc, spa);
        if (rc)
                return rc;
        if (spa_type == NFIT_SPA_PM) {
-               if (!nd_pmem_region_create(acpi_desc->nd_bus, &ndr_desc))
+               if (!nd_pmem_region_create(acpi_desc->nd_bus, ndr_desc))
                        return -ENOMEM;
        } else if (spa_type == NFIT_SPA_VOLATILE) {
-               if (!nd_volatile_region_create(acpi_desc->nd_bus, &ndr_desc))
+               if (!nd_volatile_region_create(acpi_desc->nd_bus, ndr_desc))
                        return -ENOMEM;
        }
        return 0;
@@ -937,11 +1337,14 @@ static int acpi_nfit_init(struct acpi_nfit_desc 
*acpi_desc, acpi_size sz)
        u8 *data;
        int rc;
 
+       INIT_LIST_HEAD(&acpi_desc->spa_maps);
        INIT_LIST_HEAD(&acpi_desc->spas);
        INIT_LIST_HEAD(&acpi_desc->dcrs);
        INIT_LIST_HEAD(&acpi_desc->bdws);
+       INIT_LIST_HEAD(&acpi_desc->idts);
        INIT_LIST_HEAD(&acpi_desc->memdevs);
        INIT_LIST_HEAD(&acpi_desc->dimms);
+       mutex_init(&acpi_desc->spa_map_mutex);
 
        data = (u8 *) acpi_desc->nfit;
        end = data + sz;
@@ -990,6 +1393,9 @@ static int acpi_nfit_add(struct acpi_device *adev)
        dev_set_drvdata(dev, acpi_desc);
        acpi_desc->dev = dev;
        acpi_desc->nfit = (struct acpi_table_nfit *) tbl;
+       acpi_desc->blk_enable = acpi_nfit_blk_region_enable;
+       acpi_desc->blk_disable = acpi_nfit_blk_region_disable;
+       acpi_desc->blk_do_io = acpi_nfit_blk_region_do_io;
        nd_desc = &acpi_desc->nd_desc;
        nd_desc->provider_name = "ACPI.NFIT";
        nd_desc->ndctl = acpi_nfit_ctl;
diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
index cc496ba6bbd2..1fc49cc51d4a 100644
--- a/drivers/acpi/nfit.h
+++ b/drivers/acpi/nfit.h
@@ -52,6 +52,11 @@ struct nfit_bdw {
        struct list_head list;
 };
 
+struct nfit_idt {
+       struct acpi_nfit_interleave *idt;
+       struct list_head list;
+};
+
 struct nfit_memdev {
        struct acpi_nfit_memory_map *memdev;
        struct list_head list;
@@ -62,10 +67,13 @@ struct nfit_mem {
        struct nd_dimm *nd_dimm;
        struct acpi_nfit_memory_map *memdev_dcr;
        struct acpi_nfit_memory_map *memdev_pmem;
+       struct acpi_nfit_memory_map *memdev_bdw;
        struct acpi_nfit_control_region *dcr;
        struct acpi_nfit_data_region *bdw;
        struct acpi_nfit_system_address *spa_dcr;
        struct acpi_nfit_system_address *spa_bdw;
+       struct acpi_nfit_interleave *idt_dcr;
+       struct acpi_nfit_interleave *idt_bdw;
        struct list_head list;
        struct acpi_device *adev;
        unsigned long dsm_mask;
@@ -74,16 +82,58 @@ struct nfit_mem {
 struct acpi_nfit_desc {
        struct nd_bus_descriptor nd_desc;
        struct acpi_table_nfit *nfit;
+       struct mutex spa_map_mutex;
+       struct list_head spa_maps;
        struct list_head memdevs;
        struct list_head dimms;
        struct list_head spas;
        struct list_head dcrs;
        struct list_head bdws;
+       struct list_head idts;
        struct nd_bus *nd_bus;
        struct device *dev;
        unsigned long dimm_dsm_force_en;
+       int (*blk_enable)(struct nd_bus *nd_bus, struct device *dev);
+       void (*blk_disable)(struct nd_bus *nd_bus, struct device *dev);
+       int (*blk_do_io)(struct nd_blk_region *ndbr, void *iobuf,
+                       u64 len, int write, resource_size_t dpa);
+};
+
+enum nd_blk_mmio_selector {
+       BDW,
+       DCR,
+};
+
+struct nfit_blk {
+       struct nfit_blk_mmio {
+               void *base;
+               u64 size;
+               u64 base_offset;
+               u32 line_size;
+               u32 num_lines;
+               u32 table_size;
+               struct acpi_nfit_interleave *idt;
+               struct acpi_nfit_system_address *spa;
+       } mmio[2];
+       struct nd_region *nd_region;
+       u64 bdw_offset; /* post interleave offset */
+       u64 stat_offset;
+       u64 cmd_offset;
 };
 
+struct nfit_spa_mapping {
+       struct acpi_nfit_desc *acpi_desc;
+       struct acpi_nfit_system_address *spa;
+       struct list_head list;
+       struct kref kref;
+       void *iomem;
+};
+
+static inline struct nfit_spa_mapping *to_spa_map(struct kref *kref)
+{
+       return container_of(kref, struct nfit_spa_mapping, kref);
+}
+
 static inline struct acpi_nfit_memory_map *__to_nfit_memdev(struct nfit_mem 
*nfit_mem)
 {
        if (nfit_mem->memdev_dcr)
diff --git a/drivers/block/nd/Kconfig b/drivers/block/nd/Kconfig
index 2b169806eac5..f97bf0db6519 100644
--- a/drivers/block/nd/Kconfig
+++ b/drivers/block/nd/Kconfig
@@ -34,6 +34,19 @@ config BLK_DEV_PMEM
 
          Say Y if you want to use a NVDIMM described by ACPI, E820, etc...
 
+config ND_BLK
+       tristate "BLK: Block data window (aperture) device support"
+       depends on LIBND
+       default LIBND
+       help
+         Support NVDIMMs, or other devices, that implement a BLK-mode
+         access capability.  BLK-mode access uses memory-mapped-i/o
+         apertures to access persistent media.
+
+         Say Y if your platform firmware emits an ACPI.NFIT table
+         (CONFIG_ACPI_NFIT), or otherwise exposes BLK-mode
+         capabilities.
+
 config ND_BTT_DEVS
        bool
 
diff --git a/drivers/block/nd/Makefile b/drivers/block/nd/Makefile
index 1e8fe93a0a42..29a797686429 100644
--- a/drivers/block/nd/Makefile
+++ b/drivers/block/nd/Makefile
@@ -1,11 +1,14 @@
 obj-$(CONFIG_LIBND) += libnd.o
 obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o
 obj-$(CONFIG_ND_BTT) += nd_btt.o
+obj-$(CONFIG_ND_BLK) += nd_blk.o
 
 nd_pmem-y := pmem.o
 
 nd_btt-y := btt.o
 
+nd_blk-y := blk.o
+
 libnd-y := core.o
 libnd-y += bus.o
 libnd-y += dimm_devs.o
diff --git a/drivers/block/nd/blk.c b/drivers/block/nd/blk.c
new file mode 100644
index 000000000000..464a3442fd40
--- /dev/null
+++ b/drivers/block/nd/blk.c
@@ -0,0 +1,252 @@
+/*
+ * NVDIMM Block Window Driver
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/blkdev.h>
+#include <linux/fs.h>
+#include <linux/genhd.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/nd.h>
+#include <linux/sizes.h>
+#include "nd.h"
+
+struct nd_blk_device {
+       struct request_queue *queue;
+       struct gendisk *disk;
+       struct nd_namespace_blk *nsblk;
+       struct nd_blk_region *ndbr;
+       struct nd_io ndio;
+       size_t disk_size;
+};
+
+static int nd_blk_major;
+
+static resource_size_t to_dev_offset(struct nd_namespace_blk *nsblk,
+                               resource_size_t ns_offset, unsigned int len)
+{
+       int i;
+
+       for (i = 0; i < nsblk->num_resources; i++) {
+               if (ns_offset < resource_size(nsblk->res[i])) {
+                       if (ns_offset + len > resource_size(nsblk->res[i])) {
+                               dev_WARN_ONCE(&nsblk->dev, 1,
+                                       "%s: illegal request\n", __func__);
+                               return SIZE_MAX;
+                       }
+                       return nsblk->res[i]->start + ns_offset;
+               }
+               ns_offset -= resource_size(nsblk->res[i]);
+       }
+
+       dev_WARN_ONCE(&nsblk->dev, 1, "%s: request out of range\n", __func__);
+       return SIZE_MAX;
+}
+
+static void nd_blk_make_request(struct request_queue *q, struct bio *bio)
+{
+       struct block_device *bdev = bio->bi_bdev;
+       struct gendisk *disk = bdev->bd_disk;
+       struct nd_namespace_blk *nsblk;
+       struct nd_blk_device *blk_dev;
+       struct nd_blk_region *ndbr;
+       struct bvec_iter iter;
+       struct bio_vec bvec;
+       int err = 0, rw;
+       sector_t sector;
+
+       sector = bio->bi_iter.bi_sector;
+       if (bio_end_sector(bio) > get_capacity(disk)) {
+               err = -EIO;
+               goto out;
+       }
+
+       BUG_ON(bio->bi_rw & REQ_DISCARD);
+
+       rw = bio_data_dir(bio);
+
+       blk_dev = disk->private_data;
+       nsblk = blk_dev->nsblk;
+       ndbr = blk_dev->ndbr;
+       bio_for_each_segment(bvec, bio, iter) {
+               unsigned int len = bvec.bv_len;
+               resource_size_t dev_offset;
+               void *iobuf;
+
+               BUG_ON(len > PAGE_SIZE);
+
+               dev_offset = to_dev_offset(nsblk, sector << SECTOR_SHIFT, len);
+               if (dev_offset == SIZE_MAX) {
+                       err = -EIO;
+                       goto out;
+               }
+
+               iobuf = kmap_atomic(bvec.bv_page);
+               err = ndbr->do_io(ndbr, iobuf + bvec.bv_offset, len, rw, 
dev_offset);
+               kunmap_atomic(iobuf);
+               if (err)
+                       goto out;
+
+               sector += len >> SECTOR_SHIFT;
+       }
+
+ out:
+       bio_endio(bio, err);
+}
+
+static int nd_blk_rw_bytes(struct nd_io *ndio, void *iobuf, size_t offset,
+               size_t n, unsigned long flags)
+{
+       struct nd_namespace_blk *nsblk;
+       struct nd_blk_device *blk_dev;
+       int rw = nd_data_dir(flags);
+       struct nd_blk_region *ndbr;
+       resource_size_t dev_offset;
+
+       blk_dev = container_of(ndio, typeof(*blk_dev), ndio);
+       ndbr = blk_dev->ndbr;
+       nsblk = blk_dev->nsblk;
+       dev_offset = to_dev_offset(nsblk, offset, n);
+
+       if (unlikely(offset + n > blk_dev->disk_size)) {
+               dev_WARN_ONCE(ndio->dev, 1, "%s: request out of range\n",
+                               __func__);
+               return -EFAULT;
+       }
+
+       if (dev_offset == SIZE_MAX)
+               return -EIO;
+
+       return ndbr->do_io(ndbr, iobuf, n, rw, dev_offset);
+}
+
+static const struct block_device_operations nd_blk_fops = {
+       .owner =                THIS_MODULE,
+};
+
+static int nd_blk_probe(struct device *dev)
+{
+       struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
+       struct nd_region *nd_region = to_nd_region(dev->parent);
+       struct nd_blk_device *blk_dev;
+       resource_size_t disk_size;
+       struct gendisk *disk;
+       int err;
+
+       disk_size = nd_namespace_blk_validate(nsblk);
+       if (disk_size < ND_MIN_NAMESPACE_SIZE)
+               return -ENXIO;
+
+       blk_dev = kzalloc(sizeof(*blk_dev), GFP_KERNEL);
+       if (!blk_dev)
+               return -ENOMEM;
+
+       blk_dev->disk_size      = disk_size;
+
+       blk_dev->queue = blk_alloc_queue(GFP_KERNEL);
+       if (!blk_dev->queue) {
+               err = -ENOMEM;
+               goto err_alloc_queue;
+       }
+
+       blk_queue_make_request(blk_dev->queue, nd_blk_make_request);
+       blk_queue_max_hw_sectors(blk_dev->queue, 1024);
+       blk_queue_bounce_limit(blk_dev->queue, BLK_BOUNCE_ANY);
+       blk_queue_logical_block_size(blk_dev->queue, nsblk->lbasize);
+
+       disk = blk_dev->disk = alloc_disk(0);
+       if (!disk) {
+               err = -ENOMEM;
+               goto err_alloc_disk;
+       }
+
+       blk_dev->ndbr = to_nd_blk_region(nsblk->dev.parent);
+       blk_dev->nsblk = nsblk;
+
+       disk->driverfs_dev      = dev;
+       disk->major             = nd_blk_major;
+       disk->first_minor       = 0;
+       disk->fops              = &nd_blk_fops;
+       disk->private_data      = blk_dev;
+       disk->queue             = blk_dev->queue;
+       disk->flags             = GENHD_FL_EXT_DEVT;
+       sprintf(disk->disk_name, "ndblk%d.%d", nd_region->id, nsblk->id);
+       set_capacity(disk, disk_size >> SECTOR_SHIFT);
+
+       nd_bus_lock(dev);
+       dev_set_drvdata(dev, blk_dev);
+
+       add_disk(disk);
+       nd_init_ndio(&blk_dev->ndio, nd_blk_rw_bytes, dev, disk, 0);
+       nd_register_ndio(&blk_dev->ndio);
+       nd_bus_unlock(dev);
+
+       return 0;
+
+ err_alloc_disk:
+       blk_cleanup_queue(blk_dev->queue);
+ err_alloc_queue:
+       kfree(blk_dev);
+       return err;
+}
+
+static int nd_blk_remove(struct device *dev)
+{
+       struct nd_blk_device *blk_dev = dev_get_drvdata(dev);
+
+       nd_unregister_ndio(&blk_dev->ndio);
+       del_gendisk(blk_dev->disk);
+       put_disk(blk_dev->disk);
+       blk_cleanup_queue(blk_dev->queue);
+       kfree(blk_dev);
+
+       return 0;
+}
+
+static struct nd_device_driver nd_blk_driver = {
+       .probe = nd_blk_probe,
+       .remove = nd_blk_remove,
+       .drv = {
+               .name = "nd_blk",
+       },
+       .type = ND_DRIVER_NAMESPACE_BLK,
+};
+
+static int __init nd_blk_init(void)
+{
+       int rc;
+
+       rc = register_blkdev(0, "nd_blk");
+       if (rc < 0)
+               return rc;
+
+       nd_blk_major = rc;
+       rc = nd_driver_register(&nd_blk_driver);
+
+       if (rc < 0)
+               unregister_blkdev(nd_blk_major, "nd_blk");
+
+       return rc;
+}
+
+static void __exit nd_blk_exit(void)
+{
+       driver_unregister(&nd_blk_driver.drv);
+       unregister_blkdev(nd_blk_major, "nd_blk");
+}
+
+MODULE_AUTHOR("Ross Zwisler <ross.zwis...@linux.intel.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_BLK);
+module_init(nd_blk_init);
+module_exit(nd_blk_exit);
diff --git a/drivers/block/nd/dimm_devs.c b/drivers/block/nd/dimm_devs.c
index 4b225c8b7d0a..df6c98fc2ae6 100644
--- a/drivers/block/nd/dimm_devs.c
+++ b/drivers/block/nd/dimm_devs.c
@@ -209,6 +209,15 @@ struct nd_dimm *to_nd_dimm(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(to_nd_dimm);
 
+struct nd_dimm *nd_blk_region_to_dimm(struct nd_blk_region *ndbr)
+{
+       struct nd_region *nd_region = &ndbr->nd_region;
+       struct nd_mapping *nd_mapping = &nd_region->mapping[0];
+
+       return nd_mapping->nd_dimm;
+}
+EXPORT_SYMBOL_GPL(nd_blk_region_to_dimm);
+
 struct nd_dimm_drvdata *to_ndd(struct nd_mapping *nd_mapping)
 {
        struct nd_dimm *nd_dimm = nd_mapping->nd_dimm;
diff --git a/drivers/block/nd/namespace_devs.c 
b/drivers/block/nd/namespace_devs.c
index c193ba6c6445..0734b1a4a0a3 100644
--- a/drivers/block/nd/namespace_devs.c
+++ b/drivers/block/nd/namespace_devs.c
@@ -151,6 +151,53 @@ static resource_size_t nd_namespace_blk_size(struct 
nd_namespace_blk *nsblk)
        return size;
 }
 
+resource_size_t nd_namespace_blk_validate(struct nd_namespace_blk *nsblk)
+{
+       struct nd_region *nd_region = to_nd_region(nsblk->dev.parent);
+       struct nd_mapping *nd_mapping = &nd_region->mapping[0];
+       struct nd_dimm_drvdata *ndd = to_ndd(nd_mapping);
+       struct nd_label_id label_id;
+       struct resource *res;
+       int count, i;
+
+       if (!nsblk->uuid || !nsblk->lbasize)
+               return 0;
+
+       count = 0;
+       nd_label_gen_id(&label_id, nsblk->uuid, NSLABEL_FLAG_LOCAL);
+       for_each_dpa_resource(ndd, res) {
+               if (strcmp(res->name, label_id.id) != 0)
+                       continue;
+               /*
+                * Resources with unacknoweldged adjustments indicate a
+                * failure to update labels
+                */
+               if (res->flags & DPA_RESOURCE_ADJUSTED)
+                       return 0;
+               count++;
+       }
+
+       /* These values match after a successful label update */
+       if (count != nsblk->num_resources)
+               return 0;
+
+       for (i = 0; i < nsblk->num_resources; i++) {
+               struct resource *found = NULL;
+
+               for_each_dpa_resource(ndd, res)
+                       if (res == nsblk->res[i]) {
+                               found = res;
+                               break;
+                       }
+               /* stale resource */
+               if (!found)
+                       return 0;
+       }
+
+       return nd_namespace_blk_size(nsblk);
+}
+EXPORT_SYMBOL(nd_namespace_blk_validate);
+
 static int nd_namespace_label_update(struct nd_region *nd_region, struct 
device *dev)
 {
        dev_WARN_ONCE(dev, dev->driver,
diff --git a/drivers/block/nd/nd-private.h b/drivers/block/nd/nd-private.h
index 6a864e9ae97a..b0571e334af9 100644
--- a/drivers/block/nd/nd-private.h
+++ b/drivers/block/nd/nd-private.h
@@ -22,7 +22,6 @@ extern struct list_head nd_bus_list;
 extern struct mutex nd_bus_list_mutex;
 extern int nd_dimm_major;
 
-struct block_device;
 struct nd_io_claim;
 struct nd_btt;
 struct nd_io;
@@ -50,8 +49,8 @@ struct nd_dimm {
 
 struct nd_io *ndio_lookup(struct nd_bus *nd_bus, const char *diskname);
 bool is_nd_dimm(struct device *dev);
-bool is_nd_blk(struct device *dev);
 bool is_nd_pmem(struct device *dev);
+bool is_nd_blk(struct device *dev);
 #if IS_ENABLED(CONFIG_ND_BTT_DEVS)
 bool is_nd_btt(struct device *dev);
 struct nd_btt *nd_btt_create(struct nd_bus *nd_bus);
diff --git a/drivers/block/nd/nd.h b/drivers/block/nd/nd.h
index b706f25da7e5..b830801c9892 100644
--- a/drivers/block/nd/nd.h
+++ b/drivers/block/nd/nd.h
@@ -113,6 +113,15 @@ struct nd_region {
        struct nd_mapping mapping[0];
 };
 
+struct nd_blk_region {
+       int (*enable)(struct nd_bus *nd_bus, struct device *dev);
+       void (*disable)(struct nd_bus *nd_bus, struct device *dev);
+       int (*do_io)(struct nd_blk_region *ndbr, void *iobuf, u64 len,
+                       int write, resource_size_t dpa);
+       void *blk_provider_data;
+       struct nd_region nd_region;
+};
+
 /*
  * Lookup next in the repeating sequence of 01, 10, and 11.
  */
@@ -232,8 +241,6 @@ struct nd_btt *to_nd_btt(struct device *dev);
 struct btt_sb;
 u64 nd_btt_sb_checksum(struct btt_sb *btt_sb);
 struct nd_region *to_nd_region(struct device *dev);
-unsigned int nd_region_acquire_lane(struct nd_region *nd_region);
-void nd_region_release_lane(struct nd_region *nd_region, unsigned int lane);
 int nd_region_to_namespace_type(struct nd_region *nd_region);
 int nd_region_register_namespaces(struct nd_region *nd_region, int *err);
 u64 nd_region_interleave_set_cookie(struct nd_region *nd_region);
@@ -245,4 +252,6 @@ void nd_dimm_free_dpa(struct nd_dimm_drvdata *ndd, struct 
resource *res);
 struct resource *nd_dimm_allocate_dpa(struct nd_dimm_drvdata *ndd,
                struct nd_label_id *label_id, resource_size_t start,
                resource_size_t n);
+int nd_blk_region_init(struct nd_region *nd_region);
+resource_size_t nd_namespace_blk_validate(struct nd_namespace_blk *nsblk);
 #endif /* __ND_H__ */
diff --git a/drivers/block/nd/region.c b/drivers/block/nd/region.c
index 0e872f54dcd2..75ae27279f0e 100644
--- a/drivers/block/nd/region.c
+++ b/drivers/block/nd/region.c
@@ -94,11 +94,10 @@ EXPORT_SYMBOL(nd_region_release_lane);
 
 static int nd_region_probe(struct device *dev)
 {
-       int err;
+       int err, rc;
        static unsigned long once;
        struct nd_region_namespaces *num_ns;
        struct nd_region *nd_region = to_nd_region(dev);
-       int rc = nd_region_register_namespaces(nd_region, &err);
 
        if (nd_region->num_lanes > num_online_cpus()
                        && nd_region->num_lanes < num_possible_cpus()
@@ -110,6 +109,11 @@ static int nd_region_probe(struct device *dev)
                                nd_region->num_lanes);
        }
 
+       rc = nd_blk_region_init(nd_region);
+       if (rc)
+               return rc;
+
+       rc = nd_region_register_namespaces(nd_region, &err);
        num_ns = devm_kzalloc(dev, sizeof(*num_ns), GFP_KERNEL);
        if (!num_ns)
                return -ENOMEM;
diff --git a/drivers/block/nd/region_devs.c b/drivers/block/nd/region_devs.c
index 4965004147ae..88af2a42397f 100644
--- a/drivers/block/nd/region_devs.c
+++ b/drivers/block/nd/region_devs.c
@@ -11,6 +11,7 @@
  * General Public License for more details.
  */
 #include <linux/scatterlist.h>
+#include <linux/highmem.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/sort.h>
@@ -33,7 +34,10 @@ static void nd_region_release(struct device *dev)
                put_device(&nd_dimm->dev);
        }
        ida_simple_remove(&region_ida, nd_region->id);
-       kfree(nd_region);
+       if (is_nd_blk(dev))
+               kfree(to_nd_blk_region(dev));
+       else
+               kfree(nd_region);
 }
 
 static struct device_type nd_blk_device_type = {
@@ -70,6 +74,33 @@ struct nd_region *to_nd_region(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(to_nd_region);
 
+struct nd_blk_region *to_nd_blk_region(struct device *dev)
+{
+       struct nd_region *nd_region = to_nd_region(dev);
+
+       WARN_ON(!is_nd_blk(dev));
+       return container_of(nd_region, struct nd_blk_region, nd_region);
+}
+EXPORT_SYMBOL_GPL(to_nd_blk_region);
+
+void *nd_region_provider_data(struct nd_region *nd_region)
+{
+       return nd_region->provider_data;
+}
+EXPORT_SYMBOL_GPL(nd_region_provider_data);
+
+void *nd_blk_region_provider_data(struct nd_blk_region *ndbr)
+{
+       return ndbr->blk_provider_data;
+}
+EXPORT_SYMBOL_GPL(nd_blk_region_provider_data);
+
+void nd_blk_region_set_provider_data(struct nd_blk_region *ndbr, void *data)
+{
+       ndbr->blk_provider_data = data;
+}
+EXPORT_SYMBOL_GPL(nd_blk_region_set_provider_data);
+
 /**
  * nd_region_to_namespace_type() - region to an integer namespace type
  * @nd_region: region-device to interrogate
@@ -344,14 +375,13 @@ u64 nd_region_interleave_set_cookie(struct nd_region 
*nd_region)
 
 /*
  * Upon successful probe/remove, take/release a reference on the
- * associated interleave set (if present)
+ * associated dimms in the interleave set, on successful probe of a BLK
+ * namespace check if we need a new seed, and on remove or failed probe
+ * of a BLK region notify the provider to disable the region.
  */
 static void nd_region_notify_driver_action(struct nd_bus *nd_bus,
                struct device *dev, int rc, bool probe)
 {
-       if (rc)
-               return;
-
        if (is_nd_pmem(dev) || is_nd_blk(dev)) {
                struct nd_region *nd_region = to_nd_region(dev);
                int i;
@@ -360,11 +390,16 @@ static void nd_region_notify_driver_action(struct nd_bus 
*nd_bus,
                        struct nd_mapping *nd_mapping = &nd_region->mapping[i];
                        struct nd_dimm *nd_dimm = nd_mapping->nd_dimm;
 
-                       if (probe)
+                       if (probe && rc == 0)
                                atomic_inc(&nd_dimm->busy);
-                       else
+                       else if (!probe)
                                atomic_dec(&nd_dimm->busy);
                }
+
+               if (is_nd_pmem(dev) || (probe && rc == 0))
+                       return;
+
+               to_nd_blk_region(dev)->disable(nd_bus, dev);
        } else if (dev->parent && is_nd_blk(dev->parent) && probe && rc == 0) {
                struct nd_region *nd_region = to_nd_region(dev->parent);
 
@@ -508,11 +543,21 @@ struct attribute_group nd_mapping_attribute_group = {
 };
 EXPORT_SYMBOL_GPL(nd_mapping_attribute_group);
 
-void *nd_region_provider_data(struct nd_region *nd_region)
+int nd_blk_region_init(struct nd_region *nd_region)
 {
-       return nd_region->provider_data;
+       struct device *dev = &nd_region->dev;
+       struct nd_bus *nd_bus = walk_to_nd_bus(dev);
+
+       if (!is_nd_blk(dev))
+               return 0;
+
+       if (nd_region->ndr_mappings < 1) {
+               dev_err(dev, "invalid BLK region\n");
+               return -ENXIO;
+       }
+
+       return to_nd_blk_region(dev)->enable(nd_bus, dev);
 }
-EXPORT_SYMBOL_GPL(nd_region_provider_data);
 
 static noinline struct nd_region *nd_region_create(struct nd_bus *nd_bus,
                struct nd_region_desc *ndr_desc, struct device_type *dev_type)
@@ -534,9 +579,28 @@ static noinline struct nd_region *nd_region_create(struct 
nd_bus *nd_bus,
                }
        }
 
-       nd_region = kzalloc(sizeof(struct nd_region)
-                       + sizeof(struct nd_mapping) * ndr_desc->num_mappings,
-                       GFP_KERNEL);
+       if (dev_type == &nd_blk_device_type) {
+               struct nd_blk_region_desc *ndbr_desc;
+               struct nd_blk_region *ndbr;
+
+               ndbr_desc = container_of(ndr_desc, typeof(*ndbr_desc), 
ndr_desc);
+               ndbr = kzalloc(sizeof(*ndbr) + sizeof(struct nd_mapping)
+                               * ndr_desc->num_mappings,
+                               GFP_KERNEL);
+               if (ndbr) {
+                       nd_region = &ndbr->nd_region;
+                       ndbr->enable = ndbr_desc->enable;
+                       ndbr->disable = ndbr_desc->disable;
+                       ndbr->do_io = ndbr_desc->do_io;
+               } else
+                       nd_region = NULL;
+       } else {
+               nd_region = kzalloc(sizeof(struct nd_region)
+                               + sizeof(struct nd_mapping)
+                               * ndr_desc->num_mappings,
+                               GFP_KERNEL);
+       }
+
        if (!nd_region)
                return NULL;
        nd_region->id = ida_simple_get(&region_ida, 0, 0, GFP_KERNEL);
diff --git a/include/linux/libnd.h b/include/linux/libnd.h
index 6146690b23e7..31969f082407 100644
--- a/include/linux/libnd.h
+++ b/include/linux/libnd.h
@@ -81,6 +81,15 @@ struct nd_region_desc {
 
 struct nd_bus;
 struct device;
+struct nd_blk_region;
+struct nd_blk_region_desc {
+       int (*enable)(struct nd_bus *nd_bus, struct device *dev);
+       void (*disable)(struct nd_bus *nd_bus, struct device *dev);
+       int (*do_io)(struct nd_blk_region *ndbr, void *iobuf, u64 len,
+                       int write, resource_size_t dpa);
+       struct nd_region_desc ndr_desc;
+};
+
 struct nd_bus *__nd_bus_register(struct device *parent,
                struct nd_bus_descriptor *nfit_desc, struct module *module);
 #define nd_bus_register(parent, desc) \
@@ -89,10 +98,10 @@ void nd_bus_unregister(struct nd_bus *nd_bus);
 struct nd_bus *to_nd_bus(struct device *dev);
 struct nd_dimm *to_nd_dimm(struct device *dev);
 struct nd_region *to_nd_region(struct device *dev);
+struct nd_blk_region *to_nd_blk_region(struct device *dev);
 struct nd_bus_descriptor *to_nd_desc(struct nd_bus *nd_bus);
 const char *nd_dimm_name(struct nd_dimm *nd_dimm);
 void *nd_dimm_provider_data(struct nd_dimm *nd_dimm);
-void *nd_region_provider_data(struct nd_region *nd_region);
 struct nd_dimm *nd_dimm_create(struct nd_bus *nd_bus, void *provider_data,
                const struct attribute_group **groups, unsigned long flags,
                unsigned long *dsm_mask);
@@ -110,5 +119,11 @@ struct nd_region *nd_blk_region_create(struct nd_bus 
*nd_bus,
                struct nd_region_desc *ndr_desc);
 struct nd_region *nd_volatile_region_create(struct nd_bus *nd_bus,
                struct nd_region_desc *ndr_desc);
+void *nd_region_provider_data(struct nd_region *nd_region);
+void *nd_blk_region_provider_data(struct nd_blk_region *ndbr);
+void nd_blk_region_set_provider_data(struct nd_blk_region *ndbr, void *data);
+struct nd_dimm *nd_blk_region_to_dimm(struct nd_blk_region *ndbr);
+unsigned int nd_region_acquire_lane(struct nd_region *nd_region);
+void nd_region_release_lane(struct nd_region *nd_region, unsigned int lane);
 u64 nd_fletcher64(void *addr, size_t len, bool le);
 #endif /* __LIBND_H__ */

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