hmem.c

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/platform_device.h>
  3#include <linux/memregion.h>
  4#include <linux/module.h>
  5#include <linux/dax.h>
  6#include "../bus.h"
  7
  8static bool region_idle;
  9module_param_named(region_idle, region_idle, bool, 0644);
 10
 11static int dax_hmem_probe(struct platform_device *pdev)
 12{
 13	unsigned long flags = IORESOURCE_DAX_KMEM;
 14	struct device *dev = &pdev->dev;
 15	struct dax_region *dax_region;
 16	struct memregion_info *mri;
 17	struct dev_dax_data data;
 18
 19	/*
 20	 * @region_idle == true indicates that an administrative agent
 21	 * wants to manipulate the range partitioning before the devices
 22	 * are created, so do not send them to the dax_kmem driver by
 23	 * default.
 24	 */
 25	if (region_idle)
 26		flags = 0;
 27
 28	mri = dev->platform_data;
 29	dax_region = alloc_dax_region(dev, pdev->id, &mri->range,
 30				      mri->target_node, PMD_SIZE, flags);
 31	if (!dax_region)
 32		return -ENOMEM;
 33
 34	data = (struct dev_dax_data) {
 35		.dax_region = dax_region,
 36		.id = -1,
 37		.size = region_idle ? 0 : range_len(&mri->range),
 38		.memmap_on_memory = false,
 39	};
 40
 41	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
 42}
 43
 44static struct platform_driver dax_hmem_driver = {
 45	.probe = dax_hmem_probe,
 46	.driver = {
 47		.name = "hmem",
 48	},
 49};
 50
 51static void release_memregion(void *data)
 52{
 53	memregion_free((long) data);
 54}
 55
 56static void release_hmem(void *pdev)
 57{
 58	platform_device_unregister(pdev);
 59}
 60
 61static int hmem_register_device(struct device *host, int target_nid,
 62				const struct resource *res)
 63{
 64	struct platform_device *pdev;
 65	struct memregion_info info;
 66	long id;
 67	int rc;
 68
 69	if (IS_ENABLED(CONFIG_CXL_REGION) &&
 70	    region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
 71			      IORES_DESC_CXL) != REGION_DISJOINT) {
 72		dev_dbg(host, "deferring range to CXL: %pr\n", res);
 73		return 0;
 74	}
 75
 76	rc = region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
 77			       IORES_DESC_SOFT_RESERVED);
 78	if (rc != REGION_INTERSECTS)
 79		return 0;
 80
 81	id = memregion_alloc(GFP_KERNEL);
 82	if (id < 0) {
 83		dev_err(host, "memregion allocation failure for %pr\n", res);
 84		return -ENOMEM;
 85	}
 86	rc = devm_add_action_or_reset(host, release_memregion, (void *) id);
 87	if (rc)
 88		return rc;
 89
 90	pdev = platform_device_alloc("hmem", id);
 91	if (!pdev) {
 92		dev_err(host, "device allocation failure for %pr\n", res);
 93		return -ENOMEM;
 94	}
 95
 96	pdev->dev.numa_node = numa_map_to_online_node(target_nid);
 97	info = (struct memregion_info) {
 98		.target_node = target_nid,
 99		.range = {
100			.start = res->start,
101			.end = res->end,
102		},
103	};
104	rc = platform_device_add_data(pdev, &info, sizeof(info));
105	if (rc < 0) {
106		dev_err(host, "memregion_info allocation failure for %pr\n",
107		       res);
108		goto out_put;
109	}
110
111	rc = platform_device_add(pdev);
112	if (rc < 0) {
113		dev_err(host, "%s add failed for %pr\n", dev_name(&pdev->dev),
114			res);
115		goto out_put;
116	}
117
118	return devm_add_action_or_reset(host, release_hmem, pdev);
119
120out_put:
121	platform_device_put(pdev);
122	return rc;
123}
124
125static int dax_hmem_platform_probe(struct platform_device *pdev)
126{
127	return walk_hmem_resources(&pdev->dev, hmem_register_device);
128}
129
130static struct platform_driver dax_hmem_platform_driver = {
131	.probe = dax_hmem_platform_probe,
132	.driver = {
133		.name = "hmem_platform",
134	},
135};
136
137static __init int dax_hmem_init(void)
138{
139	int rc;
140
141	rc = platform_driver_register(&dax_hmem_platform_driver);
142	if (rc)
143		return rc;
144
145	rc = platform_driver_register(&dax_hmem_driver);
146	if (rc)
147		platform_driver_unregister(&dax_hmem_platform_driver);
148
149	return rc;
150}
151
152static __exit void dax_hmem_exit(void)
153{
154	platform_driver_unregister(&dax_hmem_driver);
155	platform_driver_unregister(&dax_hmem_platform_driver);
156}
157
158module_init(dax_hmem_init);
159module_exit(dax_hmem_exit);
160
161/* Allow for CXL to define its own dax regions */
162#if IS_ENABLED(CONFIG_CXL_REGION)
163#if IS_MODULE(CONFIG_CXL_ACPI)
164MODULE_SOFTDEP("pre: cxl_acpi");
165#endif
166#endif
167
168MODULE_ALIAS("platform:hmem*");
169MODULE_ALIAS("platform:hmem_platform*");
170MODULE_DESCRIPTION("HMEM DAX: direct access to 'specific purpose' memory");
171MODULE_LICENSE("GPL v2");
172MODULE_AUTHOR("Intel Corporation");