+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2022 Intel Corporation. All rights reserved. */
+#include <linux/memregion.h>
+#include <linux/genalloc.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <cxl.h>
+#include "core.h"
+
+/**
+ * DOC: cxl core region
+ *
+ * CXL Regions represent mapped memory capacity in system physical address
+ * space. Whereas the CXL Root Decoders identify the bounds of potential CXL
+ * Memory ranges, Regions represent the active mapped capacity by the HDM
+ * Decoder Capability structures throughout the Host Bridges, Switches, and
+ * Endpoints in the topology.
+ */
+
+static struct cxl_region *to_cxl_region(struct device *dev);
+
+static void cxl_region_release(struct device *dev)
+{
+ struct cxl_region *cxlr = to_cxl_region(dev);
+
+ memregion_free(cxlr->id);
+ kfree(cxlr);
+}
+
+static const struct device_type cxl_region_type = {
+ .name = "cxl_region",
+ .release = cxl_region_release,
+};
+
+bool is_cxl_region(struct device *dev)
+{
+ return dev->type == &cxl_region_type;
+}
+EXPORT_SYMBOL_NS_GPL(is_cxl_region, CXL);
+
+static struct cxl_region *to_cxl_region(struct device *dev)
+{
+ if (dev_WARN_ONCE(dev, dev->type != &cxl_region_type,
+ "not a cxl_region device\n"))
+ return NULL;
+
+ return container_of(dev, struct cxl_region, dev);
+}
+
+static void unregister_region(void *dev)
+{
+ device_unregister(dev);
+}
+
+static struct lock_class_key cxl_region_key;
+
+static struct cxl_region *cxl_region_alloc(struct cxl_root_decoder *cxlrd, int id)
+{
+ struct cxl_region *cxlr;
+ struct device *dev;
+
+ cxlr = kzalloc(sizeof(*cxlr), GFP_KERNEL);
+ if (!cxlr) {
+ memregion_free(id);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ dev = &cxlr->dev;
+ device_initialize(dev);
+ lockdep_set_class(&dev->mutex, &cxl_region_key);
+ dev->parent = &cxlrd->cxlsd.cxld.dev;
+ device_set_pm_not_required(dev);
+ dev->bus = &cxl_bus_type;
+ dev->type = &cxl_region_type;
+ cxlr->id = id;
+
+ return cxlr;
+}
+
+/**
+ * devm_cxl_add_region - Adds a region to a decoder
+ * @cxlrd: root decoder
+ * @id: memregion id to create, or memregion_free() on failure
+ * @mode: mode for the endpoint decoders of this region
+ * @type: select whether this is an expander or accelerator (type-2 or type-3)
+ *
+ * This is the second step of region initialization. Regions exist within an
+ * address space which is mapped by a @cxlrd.
+ *
+ * Return: 0 if the region was added to the @cxlrd, else returns negative error
+ * code. The region will be named "regionZ" where Z is the unique region number.
+ */
+static struct cxl_region *devm_cxl_add_region(struct cxl_root_decoder *cxlrd,
+ int id,
+ enum cxl_decoder_mode mode,
+ enum cxl_decoder_type type)
+{
+ struct cxl_port *port = to_cxl_port(cxlrd->cxlsd.cxld.dev.parent);
+ struct cxl_region *cxlr;
+ struct device *dev;
+ int rc;
+
+ cxlr = cxl_region_alloc(cxlrd, id);
+ if (IS_ERR(cxlr))
+ return cxlr;
+ cxlr->mode = mode;
+ cxlr->type = type;
+
+ dev = &cxlr->dev;
+ rc = dev_set_name(dev, "region%d", id);
+ if (rc)
+ goto err;
+
+ rc = device_add(dev);
+ if (rc)
+ goto err;
+
+ rc = devm_add_action_or_reset(port->uport, unregister_region, cxlr);
+ if (rc)
+ return ERR_PTR(rc);
+
+ dev_dbg(port->uport, "%s: created %s\n",
+ dev_name(&cxlrd->cxlsd.cxld.dev), dev_name(dev));
+ return cxlr;
+
+err:
+ put_device(dev);
+ return ERR_PTR(rc);
+}
+
+static ssize_t create_pmem_region_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
+
+ return sysfs_emit(buf, "region%u\n", atomic_read(&cxlrd->region_id));
+}
+
+static ssize_t create_pmem_region_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
+ struct cxl_region *cxlr;
+ int id, rc;
+
+ rc = sscanf(buf, "region%d\n", &id);
+ if (rc != 1)
+ return -EINVAL;
+
+ rc = memregion_alloc(GFP_KERNEL);
+ if (rc < 0)
+ return rc;
+
+ if (atomic_cmpxchg(&cxlrd->region_id, id, rc) != id) {
+ memregion_free(rc);
+ return -EBUSY;
+ }
+
+ cxlr = devm_cxl_add_region(cxlrd, id, CXL_DECODER_PMEM,
+ CXL_DECODER_EXPANDER);
+ if (IS_ERR(cxlr))
+ return PTR_ERR(cxlr);
+
+ return len;
+}
+DEVICE_ATTR_RW(create_pmem_region);
+
+static struct cxl_region *
+cxl_find_region_by_name(struct cxl_root_decoder *cxlrd, const char *name)
+{
+ struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
+ struct device *region_dev;
+
+ region_dev = device_find_child_by_name(&cxld->dev, name);
+ if (!region_dev)
+ return ERR_PTR(-ENODEV);
+
+ return to_cxl_region(region_dev);
+}
+
+static ssize_t delete_region_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
+ struct cxl_port *port = to_cxl_port(dev->parent);
+ struct cxl_region *cxlr;
+
+ cxlr = cxl_find_region_by_name(cxlrd, buf);
+ if (IS_ERR(cxlr))
+ return PTR_ERR(cxlr);
+
+ devm_release_action(port->uport, unregister_region, cxlr);
+ put_device(&cxlr->dev);
+
+ return len;
+}
+DEVICE_ATTR_WO(delete_region);
projects / platform / kernel / linux-starfive.git / commitdiff