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libnvdimm, e820: make CONFIG_X86_PMEM_LEGACY a tristate option

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We currently register a platform device for e820 type-12 memory and
register a nvdimm bus beneath it.  Registering the platform device
triggers the device-core machinery to probe for a driver, but that
search currently comes up empty.  Building the nvdimm-bus registration
into the e820_pmem platform device registration in this way forces
libnvdimm to be built-in.  Instead, convert the built-in portion of
CONFIG_X86_PMEM_LEGACY to simply register a platform device and move the
rest of the logic to the driver for e820_pmem, for the following
reasons:

1/ Letting e820_pmem support be a module allows building and testing
   libnvdimm.ko changes without rebooting

2/ All the normal policy around modules can be applied to e820_pmem
   (unbind to disable and/or blacklisting the module from loading by
   default)

3/ Moving the driver to a generic location and converting it to scan
   "iomem_resource" rather than "e820.map" means any other architecture can
   take advantage of this simple nvdimm resource discovery mechanism by
   registering a resource named "Persistent Memory (legacy)"

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams
2015-08-19 00:34:34 -04:00
parent 6ec689542b
commit 7a67832c7e
7 changed files with 107 additions and 73 deletions
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77
arch/x86/kernel/pmem.c
View File

@@ -3,80 +3,17 @@
* Copyright (c) 2015, Intel Corporation.
*/
#include <linux/platform_device.h>
#include <linux/libnvdimm.h>
#include <linux/module.h>
#include <asm/e820.h>
static void e820_pmem_release(struct device *dev)
{
struct nvdimm_bus *nvdimm_bus = dev->platform_data;
if (nvdimm_bus)
nvdimm_bus_unregister(nvdimm_bus);
}
static struct platform_device e820_pmem = {
.name = "e820_pmem",
.id = -1,
.dev = {
.release = e820_pmem_release,
},
};
static const struct attribute_group *e820_pmem_attribute_groups[] = {
&nvdimm_bus_attribute_group,
NULL,
};
static const struct attribute_group *e820_pmem_region_attribute_groups[] = {
&nd_region_attribute_group,
&nd_device_attribute_group,
NULL,
};
static __init int register_e820_pmem(void)
{
static struct nvdimm_bus_descriptor nd_desc;
struct device *dev = &e820_pmem.dev;
struct nvdimm_bus *nvdimm_bus;
int rc, i;
struct platform_device *pdev;
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;
memset(&ndr_desc, 0, sizeof(ndr_desc));
ndr_desc.res = &res;
ndr_desc.attr_groups = e820_pmem_region_attribute_groups;
ndr_desc.numa_node = NUMA_NO_NODE;
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;
/*
* See drivers/nvdimm/e820.c for the implementation, this is
* simply here to trigger the module to load on demand.
*/
pdev = platform_device_alloc("e820_pmem", -1);
return platform_device_add(pdev);
}
device_initcall(register_e820_pmem);