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/pfn_t.h>
  6#include <linux/dax.h>
  7#include "../bus.h"
  8
  9static bool region_idle;
 10module_param_named(region_idle, region_idle, bool, 0644);
 11
 12static int dax_hmem_probe(struct platform_device *pdev)
 13{
 14	unsigned long flags = IORESOURCE_DAX_KMEM;
 15	struct device *dev = &pdev->dev;
 16	struct dax_region *dax_region;
 17	struct memregion_info *mri;
 18	struct dev_dax_data data;
 19
 20	/*
 21	 * @region_idle == true indicates that an administrative agent
 22	 * wants to manipulate the range partitioning before the devices
 23	 * are created, so do not send them to the dax_kmem driver by
 24	 * default.
 25	 */
 26	if (region_idle)
 27		flags = 0;
 28
 29	mri = dev->platform_data;
 30	dax_region = alloc_dax_region(dev, pdev->id, &mri->range,
 31				      mri->target_node, PMD_SIZE, flags);
 32	if (!dax_region)
 33		return -ENOMEM;
 34
 35	data = (struct dev_dax_data) {
 36		.dax_region = dax_region,
 37		.id = -1,
 38		.size = region_idle ? 0 : range_len(&mri->range),
 39		.memmap_on_memory = false,
 40	};
 41
 42	return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
 43}
 44
 45static struct platform_driver dax_hmem_driver = {
 46	.probe = dax_hmem_probe,
 47	.driver = {
 48		.name = "hmem",
 49	},
 50};
 51
 52static void release_memregion(void *data)
 53{
 54	memregion_free((long) data);
 55}
 56
 57static void release_hmem(void *pdev)
 58{
 59	platform_device_unregister(pdev);
 60}
 61
 62static int hmem_register_device(struct device *host, int target_nid,
 63				const struct resource *res)
 64{
 65	struct platform_device *pdev;
 66	struct memregion_info info;
 67	long id;
 68	int rc;
 69
 70	if (IS_ENABLED(CONFIG_CXL_REGION) &&
 71	    region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
 72			      IORES_DESC_CXL) != REGION_DISJOINT) {
 73		dev_dbg(host, "deferring range to CXL: %pr\n", res);
 74		return 0;
 75	}
 76
 77	rc = region_intersects(res->start, resource_size(res), IORESOURCE_MEM,
 78			       IORES_DESC_SOFT_RESERVED);
 79	if (rc != REGION_INTERSECTS)
 80		return 0;
 81
 82	id = memregion_alloc(GFP_KERNEL);
 83	if (id < 0) {
 84		dev_err(host, "memregion allocation failure for %pr\n", res);
 85		return -ENOMEM;
 86	}
 87	rc = devm_add_action_or_reset(host, release_memregion, (void *) id);
 88	if (rc)
 89		return rc;
 90
 91	pdev = platform_device_alloc("hmem", id);
 92	if (!pdev) {
 93		dev_err(host, "device allocation failure for %pr\n", res);
 94		return -ENOMEM;
 95	}
 96
 97	pdev->dev.numa_node = numa_map_to_online_node(target_nid);
 98	info = (struct memregion_info) {
 99		.target_node = target_nid,
100		.range = {
101			.start = res->start,
102			.end = res->end,
103		},
104	};
105	rc = platform_device_add_data(pdev, &info, sizeof(info));
106	if (rc < 0) {
107		dev_err(host, "memregion_info allocation failure for %pr\n",
108		       res);
109		goto out_put;
110	}
111
112	rc = platform_device_add(pdev);
113	if (rc < 0) {
114		dev_err(host, "%s add failed for %pr\n", dev_name(&pdev->dev),
115			res);
116		goto out_put;
117	}
118
119	return devm_add_action_or_reset(host, release_hmem, pdev);
120
121out_put:
122	platform_device_put(pdev);
123	return rc;
124}
125
126static int dax_hmem_platform_probe(struct platform_device *pdev)
127{
128	return walk_hmem_resources(&pdev->dev, hmem_register_device);
129}
130
131static struct platform_driver dax_hmem_platform_driver = {
132	.probe = dax_hmem_platform_probe,
133	.driver = {
134		.name = "hmem_platform",
135	},
136};
137
138static __init int dax_hmem_init(void)
139{
140	int rc;
141
142	rc = platform_driver_register(&dax_hmem_platform_driver);
143	if (rc)
144		return rc;
145
146	rc = platform_driver_register(&dax_hmem_driver);
147	if (rc)
148		platform_driver_unregister(&dax_hmem_platform_driver);
149
150	return rc;
151}
152
153static __exit void dax_hmem_exit(void)
154{
155	platform_driver_unregister(&dax_hmem_driver);
156	platform_driver_unregister(&dax_hmem_platform_driver);
157}
158
159module_init(dax_hmem_init);
160module_exit(dax_hmem_exit);
161
162/* Allow for CXL to define its own dax regions */
163#if IS_ENABLED(CONFIG_CXL_REGION)
164#if IS_MODULE(CONFIG_CXL_ACPI)
165MODULE_SOFTDEP("pre: cxl_acpi");
166#endif
167#endif
168
169MODULE_ALIAS("platform:hmem*");
170MODULE_ALIAS("platform:hmem_platform*");
171MODULE_DESCRIPTION("HMEM DAX: direct access to 'specific purpose' memory");
172MODULE_LICENSE("GPL v2");
173MODULE_AUTHOR("Intel Corporation");