libnvdimm, pmem: add libnvdimm support to the pmem driver

nd_pmem attaches to persistent memory regions and namespaces emitted by
the libnvdimm subsystem, and, same as the original pmem driver, presents
the system-physical-address range as a block device.

The existing e820-type-12 to pmem setup is converted to an nvdimm_bus
that emits an nd_namespace_io device.

Note that the X in 'pmemX' is now derived from the parent region.  This
provides some stability to the pmem devices names from boot-to-boot.
The minor numbers are also more predictable by passing 0 to
alloc_disk().

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
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>

3 files changed, 96 insertions, 67 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 226d5696e1d1..1a2cbf641667 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1424,6 +1424,9 @@ source "mm/Kconfig"
 
 config X86_PMEM_LEGACY
         bool "Support non-standard NVDIMMs and ADR protected memory"
+        depends on PHYS_ADDR_T_64BIT
+        depends on BLK_DEV
+        select LIBNVDIMM
         help
           Treat memory marked using the non-standard e820 type of 12 as used
           by the Intel Sandy Bridge-EP reference BIOS as protected memory.
diff --git a/arch/x86/kernel/pmem.c b/arch/x86/kernel/pmem.c
index 3420c874ddc5..0f4ef472ab9e 100644
--- a/arch/x86/kernel/pmem.c
+++ b/arch/x86/kernel/pmem.c
@@ -1,53 +1,81 @@
 /*
  * Copyright (c) 2015, Christoph Hellwig.
+ * Copyright (c) 2015, Intel Corporation.
  */
-#include <linux/memblock.h>
 #include <linux/platform_device.h>
-#include <linux/slab.h>
+#include <linux/libnvdimm.h>
+#include <linux/module.h>
 #include <asm/e820.h>
-#include <asm/page_types.h>
-#include <asm/setup.h>
 
-static __init void register_pmem_device(struct resource *res)
+static void e820_pmem_release(struct device *dev)
 {
-        struct platform_device *pdev;
-        int error;
+        struct nvdimm_bus *nvdimm_bus = dev->platform_data;
 
-        pdev = platform_device_alloc("pmem", PLATFORM_DEVID_AUTO);
-        if (!pdev)
-                return;
+        if (nvdimm_bus)
+                nvdimm_bus_unregister(nvdimm_bus);
+}
 
-        error = platform_device_add_resources(pdev, res, 1);
-        if (error)
-                goto out_put_pdev;
+static struct platform_device e820_pmem = {
+        .name = "e820_pmem",
+        .id = -1,
+        .dev = {
+                .release = e820_pmem_release,
+        },
+};
 
-        error = platform_device_add(pdev);
-        if (error)
-                goto out_put_pdev;
-        return;
+static const struct attribute_group *e820_pmem_attribute_groups[] = {
+        &nvdimm_bus_attribute_group,
+        NULL,
+};
 
-out_put_pdev:
-        dev_warn(&pdev->dev, "failed to add 'pmem' (persistent memory) device!\n");
-        platform_device_put(pdev);
-}
+static const struct attribute_group *e820_pmem_region_attribute_groups[] = {
+        &nd_region_attribute_group,
+        &nd_device_attribute_group,
+        NULL,
+};
 
-static __init int register_pmem_devices(void)
+static __init int register_e820_pmem(void)
 {
-        int i;
+        static struct nvdimm_bus_descriptor nd_desc;
+        struct device *dev = &e820_pmem.dev;
+        struct nvdimm_bus *nvdimm_bus;
+        int rc, i;
+
+        rc = platform_device_register(&e820_pmem);
+        if (rc)
+                return rc;
+
+        nd_desc.attr_groups = e820_pmem_attribute_groups;
+        nd_desc.provider_name = "e820";
+        nvdimm_bus = nvdimm_bus_register(dev, &nd_desc);
+        if (!nvdimm_bus)
+                goto err;
+        dev->platform_data = nvdimm_bus;
 
         for (i = 0; i < e820.nr_map; i++) {
                 struct e820entry *ei = &e820.map[i];
+                struct resource res = {
+                        .flags  = IORESOURCE_MEM,
+                        .start  = ei->addr,
+                        .end    = ei->addr + ei->size - 1,
+                };
+                struct nd_region_desc ndr_desc;
+
+                if (ei->type != E820_PRAM)
+                        continue;
 
-                if (ei->type == E820_PRAM) {
-                        struct resource res = {
-                                .flags  = IORESOURCE_MEM,
-                                .start  = ei->addr,
-                                .end    = ei->addr + ei->size - 1,
-                        };
-                        register_pmem_device(&res);
-                }
+                memset(&ndr_desc, 0, sizeof(ndr_desc));
+                ndr_desc.res = &res;
+                ndr_desc.attr_groups = e820_pmem_region_attribute_groups;
+                if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
+                        goto err;
         }
 
         return 0;
+
+ err:
+        dev_err(dev, "failed to register legacy persistent memory ranges\n");
+        platform_device_unregister(&e820_pmem);
+        return -ENXIO;
 }
-device_initcall(register_pmem_devices);
+device_initcall(register_e820_pmem);
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index eabf4a8d0085..d46975ed9e40 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -1,7 +1,7 @@
 /*
  * Persistent Memory Driver
  *
- * Copyright (c) 2014, Intel Corporation.
+ * Copyright (c) 2014-2015, Intel Corporation.
  * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
  * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
  *
@@ -23,8 +23,8 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/slab.h>
-
-#define PMEM_MINORS             16
+#include <linux/nd.h>
+#include "nd.h"
 
 struct pmem_device {
         struct request_queue    *pmem_queue;
@@ -37,7 +37,6 @@ struct pmem_device {
 };
 
 static int pmem_major;
-static atomic_t pmem_index;
 
 static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
                         unsigned int len, unsigned int off, int rw,
@@ -118,11 +117,12 @@ static const struct block_device_operations pmem_fops = {
         .direct_access =        pmem_direct_access,
 };
 
-static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
+static struct pmem_device *pmem_alloc(struct device *dev,
+                struct resource *res, int id)
 {
         struct pmem_device *pmem;
         struct gendisk *disk;
-        int idx, err;
+        int err;
 
         err = -ENOMEM;
         pmem = kzalloc(sizeof(*pmem), GFP_KERNEL);
@@ -134,7 +134,8 @@ static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
 
         err = -EINVAL;
         if (!request_mem_region(pmem->phys_addr, pmem->size, "pmem")) {
-                dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n", &pmem->phys_addr, pmem->size);
+                dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
+                                &pmem->phys_addr, pmem->size);
                 goto out_free_dev;
         }
 
@@ -155,19 +156,17 @@ static struct pmem_device *pmem_alloc(struct device *dev, struct resource *res)
         blk_queue_max_hw_sectors(pmem->pmem_queue, 1024);
         blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
 
-        disk = alloc_disk(PMEM_MINORS);
+        disk = alloc_disk(0);
         if (!disk)
                 goto out_free_queue;
 
-        idx = atomic_inc_return(&pmem_index) - 1;
-
         disk->major             = pmem_major;
-        disk->first_minor       = PMEM_MINORS * idx;
+        disk->first_minor       = 0;
         disk->fops              = &pmem_fops;
         disk->private_data      = pmem;
         disk->queue             = pmem->pmem_queue;
         disk->flags             = GENHD_FL_EXT_DEVT;
-        sprintf(disk->disk_name, "pmem%d", idx);
+        sprintf(disk->disk_name, "pmem%d", id);
         disk->driverfs_dev = dev;
         set_capacity(disk, pmem->size >> 9);
         pmem->pmem_disk = disk;
@@ -198,42 +197,38 @@ static void pmem_free(struct pmem_device *pmem)
         kfree(pmem);
 }
 
-static int pmem_probe(struct platform_device *pdev)
+static int nd_pmem_probe(struct device *dev)
 {
+        struct nd_region *nd_region = to_nd_region(dev->parent);
+        struct nd_namespace_io *nsio = to_nd_namespace_io(dev);
         struct pmem_device *pmem;
-        struct resource *res;
-
-        if (WARN_ON(pdev->num_resources > 1))
-                return -ENXIO;
-
-        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-        if (!res)
-                return -ENXIO;
 
-        pmem = pmem_alloc(&pdev->dev, res);
+        pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
         if (IS_ERR(pmem))
                 return PTR_ERR(pmem);
 
-        platform_set_drvdata(pdev, pmem);
+        dev_set_drvdata(dev, pmem);
 
         return 0;
 }
 
-static int pmem_remove(struct platform_device *pdev)
+static int nd_pmem_remove(struct device *dev)
 {
-        struct pmem_device *pmem = platform_get_drvdata(pdev);
+        struct pmem_device *pmem = dev_get_drvdata(dev);
 
         pmem_free(pmem);
         return 0;
 }
 
-static struct platform_driver pmem_driver = {
-        .probe          = pmem_probe,
-        .remove         = pmem_remove,
-        .driver         = {
-                .owner  = THIS_MODULE,
-                .name   = "pmem",
+MODULE_ALIAS("pmem");
+MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
+static struct nd_device_driver nd_pmem_driver = {
+        .probe = nd_pmem_probe,
+        .remove = nd_pmem_remove,
+        .drv = {
+                .name = "nd_pmem",
         },
+        .type = ND_DRIVER_NAMESPACE_IO,
 };
 
 static int __init pmem_init(void)
@@ -244,16 +239,19 @@ static int __init pmem_init(void)
         if (pmem_major < 0)
                 return pmem_major;
 
-        error = platform_driver_register(&pmem_driver);
-        if (error)
+        error = nd_driver_register(&nd_pmem_driver);
+        if (error) {
                 unregister_blkdev(pmem_major, "pmem");
-        return error;
+                return error;
+        }
+
+        return 0;
 }
 module_init(pmem_init);
 
 static void pmem_exit(void)
 {
-        platform_driver_unregister(&pmem_driver);
+        driver_unregister(&nd_pmem_driver.drv);
         unregister_blkdev(pmem_major, "pmem");
 }
 module_exit(pmem_exit);