linux/drivers/dax/hmem.c
Dan Williams a6c7f4c6ae device-dax: Add a driver for "hmem" devices
Platform firmware like EFI/ACPI may publish "hmem" platform devices.
Such a device is a performance differentiated memory range likely
reserved for an application specific use case. The driver gives access
to 100% of the capacity via a device-dax mmap instance by default.

However, if over-subscription and other kernel memory management is
desired the resulting dax device can be assigned to the core-mm via the
kmem driver.

This consumes "hmem" devices the producer of "hmem" devices is saved for
a follow-on patch so that it can reference the new CONFIG_DEV_DAX_HMEM
symbol to gate performing the enumeration work.

Reported-by: kbuild test robot <lkp@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-11-07 15:45:00 +01:00

57 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/platform_device.h>
#include <linux/memregion.h>
#include <linux/module.h>
#include <linux/pfn_t.h>
#include "bus.h"
static int dax_hmem_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct dev_pagemap pgmap = { };
struct dax_region *dax_region;
struct memregion_info *mri;
struct dev_dax *dev_dax;
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -ENOMEM;
mri = dev->platform_data;
memcpy(&pgmap.res, res, sizeof(*res));
dax_region = alloc_dax_region(dev, pdev->id, res, mri->target_node,
PMD_SIZE, PFN_DEV|PFN_MAP);
if (!dax_region)
return -ENOMEM;
dev_dax = devm_create_dev_dax(dax_region, 0, &pgmap);
if (IS_ERR(dev_dax))
return PTR_ERR(dev_dax);
/* child dev_dax instances now own the lifetime of the dax_region */
dax_region_put(dax_region);
return 0;
}
static int dax_hmem_remove(struct platform_device *pdev)
{
/* devm handles teardown */
return 0;
}
static struct platform_driver dax_hmem_driver = {
.probe = dax_hmem_probe,
.remove = dax_hmem_remove,
.driver = {
.name = "hmem",
},
};
module_platform_driver(dax_hmem_driver);
MODULE_ALIAS("platform:hmem*");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Intel Corporation");