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Diffstat (limited to 'drivers/dax/hmem/device.c')
-rw-r--r--drivers/dax/hmem/device.c95
1 files changed, 95 insertions, 0 deletions
diff --git a/drivers/dax/hmem/device.c b/drivers/dax/hmem/device.c
new file mode 100644
index 0000000000..f9e1a76a04
--- /dev/null
+++ b/drivers/dax/hmem/device.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/platform_device.h>
+#include <linux/memregion.h>
+#include <linux/module.h>
+#include <linux/dax.h>
+#include <linux/mm.h>
+
+static bool nohmem;
+module_param_named(disable, nohmem, bool, 0444);
+
+static bool platform_initialized;
+static DEFINE_MUTEX(hmem_resource_lock);
+static struct resource hmem_active = {
+ .name = "HMEM devices",
+ .start = 0,
+ .end = -1,
+ .flags = IORESOURCE_MEM,
+};
+
+int walk_hmem_resources(struct device *host, walk_hmem_fn fn)
+{
+ struct resource *res;
+ int rc = 0;
+
+ mutex_lock(&hmem_resource_lock);
+ for (res = hmem_active.child; res; res = res->sibling) {
+ rc = fn(host, (int) res->desc, res);
+ if (rc)
+ break;
+ }
+ mutex_unlock(&hmem_resource_lock);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(walk_hmem_resources);
+
+static void __hmem_register_resource(int target_nid, struct resource *res)
+{
+ struct platform_device *pdev;
+ struct resource *new;
+ int rc;
+
+ new = __request_region(&hmem_active, res->start, resource_size(res), "",
+ 0);
+ if (!new) {
+ pr_debug("hmem range %pr already active\n", res);
+ return;
+ }
+
+ new->desc = target_nid;
+
+ if (platform_initialized)
+ return;
+
+ pdev = platform_device_alloc("hmem_platform", 0);
+ if (!pdev) {
+ pr_err_once("failed to register device-dax hmem_platform device\n");
+ return;
+ }
+
+ rc = platform_device_add(pdev);
+ if (rc)
+ platform_device_put(pdev);
+ else
+ platform_initialized = true;
+}
+
+void hmem_register_resource(int target_nid, struct resource *res)
+{
+ if (nohmem)
+ return;
+
+ mutex_lock(&hmem_resource_lock);
+ __hmem_register_resource(target_nid, res);
+ mutex_unlock(&hmem_resource_lock);
+}
+
+static __init int hmem_register_one(struct resource *res, void *data)
+{
+ hmem_register_resource(phys_to_target_node(res->start), res);
+
+ return 0;
+}
+
+static __init int hmem_init(void)
+{
+ walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED,
+ IORESOURCE_MEM, 0, -1, NULL, hmem_register_one);
+ return 0;
+}
+
+/*
+ * As this is a fallback for address ranges unclaimed by the ACPI HMAT
+ * parsing it must be at an initcall level greater than hmat_init().
+ */
+device_initcall(hmem_init);