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 <linux/mm.h> 7 #include "../bus.h" 8 9 static bool nohmem; 10 module_param_named(disable, nohmem, bool, 0444); 11 12 static bool platform_initialized; 13 static DEFINE_MUTEX(hmem_resource_lock); 14 static struct resource hmem_active = { 15 .name = "HMEM devices", 16 .start = 0, 17 .end = -1, 18 .flags = IORESOURCE_MEM, 19 }; 20 21 int walk_hmem_resources(struct device *host, walk_hmem_fn fn) 22 { 23 struct resource *res; 24 int rc = 0; 25 26 mutex_lock(&hmem_resource_lock); 27 for (res = hmem_active.child; res; res = res->sibling) { 28 rc = fn(host, (int) res->desc, res); 29 if (rc) 30 break; 31 } 32 mutex_unlock(&hmem_resource_lock); 33 return rc; 34 } 35 EXPORT_SYMBOL_GPL(walk_hmem_resources); 36 37 static void hmem_work(struct work_struct *work) 38 { 39 /* place holder until dax_hmem driver attaches */ 40 } 41 42 static struct hmem_platform_device hmem_platform = { 43 .pdev = { 44 .name = "hmem_platform", 45 .id = 0, 46 }, 47 .work = __WORK_INITIALIZER(hmem_platform.work, hmem_work), 48 }; 49 50 static void __hmem_register_resource(int target_nid, struct resource *res) 51 { 52 struct resource *new; 53 int rc; 54 55 new = __request_region(&hmem_active, res->start, resource_size(res), "", 56 0); 57 if (!new) { 58 pr_debug("hmem range %pr already active\n", res); 59 return; 60 } 61 62 new->desc = target_nid; 63 64 if (platform_initialized) 65 return; 66 67 rc = platform_device_register(&hmem_platform.pdev); 68 if (rc) { 69 pr_err_once("failed to register device-dax hmem_platform device\n"); 70 return; 71 } 72 73 platform_initialized = true; 74 } 75 76 void hmem_register_resource(int target_nid, struct resource *res) 77 { 78 if (nohmem) 79 return; 80 81 mutex_lock(&hmem_resource_lock); 82 __hmem_register_resource(target_nid, res); 83 mutex_unlock(&hmem_resource_lock); 84 } 85 86 static __init int hmem_register_one(struct resource *res, void *data) 87 { 88 hmem_register_resource(phys_to_target_node(res->start), res); 89 90 return 0; 91 } 92 93 static __init int hmem_init(void) 94 { 95 walk_soft_reserve_res(0, -1, NULL, hmem_register_one); 96 return 0; 97 } 98 99 /* 100 * As this is a fallback for address ranges unclaimed by the ACPI HMAT 101 * parsing it must be at an initcall level greater than hmat_init(). 102 */ 103 device_initcall(hmem_init); 104