1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
new file mode 100644
index 000000000..03cf99cce
--- /dev/null
+++ b/drivers/cxl/core/memdev.c
@@ -0,0 +1,386 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2020 Intel Corporation. */
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/idr.h>
+#include <linux/pci.h>
+#include <cxlmem.h>
+#include "core.h"
+
+static DECLARE_RWSEM(cxl_memdev_rwsem);
+
+/*
+ * An entire PCI topology full of devices should be enough for any
+ * config
+ */
+#define CXL_MEM_MAX_DEVS 65536
+
+static int cxl_mem_major;
+static DEFINE_IDA(cxl_memdev_ida);
+
+static void cxl_memdev_release(struct device *dev)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+
+	ida_free(&cxl_memdev_ida, cxlmd->id);
+	kfree(cxlmd);
+}
+
+static char *cxl_memdev_devnode(struct device *dev, umode_t *mode, kuid_t *uid,
+				kgid_t *gid)
+{
+	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
+}
+
+static ssize_t firmware_version_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	return sysfs_emit(buf, "%.16s\n", cxlds->firmware_version);
+}
+static DEVICE_ATTR_RO(firmware_version);
+
+static ssize_t payload_max_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	return sysfs_emit(buf, "%zu\n", cxlds->payload_size);
+}
+static DEVICE_ATTR_RO(payload_max);
+
+static ssize_t label_storage_size_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	return sysfs_emit(buf, "%zu\n", cxlds->lsa_size);
+}
+static DEVICE_ATTR_RO(label_storage_size);
+
+static ssize_t ram_size_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+	unsigned long long len = resource_size(&cxlds->ram_res);
+
+	return sysfs_emit(buf, "%#llx\n", len);
+}
+
+static struct device_attribute dev_attr_ram_size =
+	__ATTR(size, 0444, ram_size_show, NULL);
+
+static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+	unsigned long long len = resource_size(&cxlds->pmem_res);
+
+	return sysfs_emit(buf, "%#llx\n", len);
+}
+
+static struct device_attribute dev_attr_pmem_size =
+	__ATTR(size, 0444, pmem_size_show, NULL);
+
+static ssize_t serial_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+	struct cxl_dev_state *cxlds = cxlmd->cxlds;
+
+	return sysfs_emit(buf, "%#llx\n", cxlds->serial);
+}
+static DEVICE_ATTR_RO(serial);
+
+static ssize_t numa_node_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	return sprintf(buf, "%d\n", dev_to_node(dev));
+}
+static DEVICE_ATTR_RO(numa_node);
+
+static struct attribute *cxl_memdev_attributes[] = {
+	&dev_attr_serial.attr,
+	&dev_attr_firmware_version.attr,
+	&dev_attr_payload_max.attr,
+	&dev_attr_label_storage_size.attr,
+	&dev_attr_numa_node.attr,
+	NULL,
+};
+
+static struct attribute *cxl_memdev_pmem_attributes[] = {
+	&dev_attr_pmem_size.attr,
+	NULL,
+};
+
+static struct attribute *cxl_memdev_ram_attributes[] = {
+	&dev_attr_ram_size.attr,
+	NULL,
+};
+
+static umode_t cxl_memdev_visible(struct kobject *kobj, struct attribute *a,
+				  int n)
+{
+	if (!IS_ENABLED(CONFIG_NUMA) && a == &dev_attr_numa_node.attr)
+		return 0;
+	return a->mode;
+}
+
+static struct attribute_group cxl_memdev_attribute_group = {
+	.attrs = cxl_memdev_attributes,
+	.is_visible = cxl_memdev_visible,
+};
+
+static struct attribute_group cxl_memdev_ram_attribute_group = {
+	.name = "ram",
+	.attrs = cxl_memdev_ram_attributes,
+};
+
+static struct attribute_group cxl_memdev_pmem_attribute_group = {
+	.name = "pmem",
+	.attrs = cxl_memdev_pmem_attributes,
+};
+
+static const struct attribute_group *cxl_memdev_attribute_groups[] = {
+	&cxl_memdev_attribute_group,
+	&cxl_memdev_ram_attribute_group,
+	&cxl_memdev_pmem_attribute_group,
+	NULL,
+};
+
+static const struct device_type cxl_memdev_type = {
+	.name = "cxl_memdev",
+	.release = cxl_memdev_release,
+	.devnode = cxl_memdev_devnode,
+	.groups = cxl_memdev_attribute_groups,
+};
+
+bool is_cxl_memdev(struct device *dev)
+{
+	return dev->type == &cxl_memdev_type;
+}
+EXPORT_SYMBOL_NS_GPL(is_cxl_memdev, CXL);
+
+/**
+ * set_exclusive_cxl_commands() - atomically disable user cxl commands
+ * @cxlds: The device state to operate on
+ * @cmds: bitmap of commands to mark exclusive
+ *
+ * Grab the cxl_memdev_rwsem in write mode to flush in-flight
+ * invocations of the ioctl path and then disable future execution of
+ * commands with the command ids set in @cmds.
+ */
+void set_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds)
+{
+	down_write(&cxl_memdev_rwsem);
+	bitmap_or(cxlds->exclusive_cmds, cxlds->exclusive_cmds, cmds,
+		  CXL_MEM_COMMAND_ID_MAX);
+	up_write(&cxl_memdev_rwsem);
+}
+EXPORT_SYMBOL_NS_GPL(set_exclusive_cxl_commands, CXL);
+
+/**
+ * clear_exclusive_cxl_commands() - atomically enable user cxl commands
+ * @cxlds: The device state to modify
+ * @cmds: bitmap of commands to mark available for userspace
+ */
+void clear_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds)
+{
+	down_write(&cxl_memdev_rwsem);
+	bitmap_andnot(cxlds->exclusive_cmds, cxlds->exclusive_cmds, cmds,
+		      CXL_MEM_COMMAND_ID_MAX);
+	up_write(&cxl_memdev_rwsem);
+}
+EXPORT_SYMBOL_NS_GPL(clear_exclusive_cxl_commands, CXL);
+
+static void cxl_memdev_shutdown(struct device *dev)
+{
+	struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+
+	down_write(&cxl_memdev_rwsem);
+	cxlmd->cxlds = NULL;
+	up_write(&cxl_memdev_rwsem);
+}
+
+static void cxl_memdev_unregister(void *_cxlmd)
+{
+	struct cxl_memdev *cxlmd = _cxlmd;
+	struct device *dev = &cxlmd->dev;
+
+	cdev_device_del(&cxlmd->cdev, dev);
+	cxl_memdev_shutdown(dev);
+	put_device(dev);
+}
+
+static void detach_memdev(struct work_struct *work)
+{
+	struct cxl_memdev *cxlmd;
+
+	cxlmd = container_of(work, typeof(*cxlmd), detach_work);
+	device_release_driver(&cxlmd->dev);
+	put_device(&cxlmd->dev);
+}
+
+static struct lock_class_key cxl_memdev_key;
+
+static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds,
+					   const struct file_operations *fops)
+{
+	struct cxl_memdev *cxlmd;
+	struct device *dev;
+	struct cdev *cdev;
+	int rc;
+
+	cxlmd = kzalloc(sizeof(*cxlmd), GFP_KERNEL);
+	if (!cxlmd)
+		return ERR_PTR(-ENOMEM);
+
+	rc = ida_alloc_range(&cxl_memdev_ida, 0, CXL_MEM_MAX_DEVS, GFP_KERNEL);
+	if (rc < 0)
+		goto err;
+	cxlmd->id = rc;
+
+	dev = &cxlmd->dev;
+	device_initialize(dev);
+	lockdep_set_class(&dev->mutex, &cxl_memdev_key);
+	dev->parent = cxlds->dev;
+	dev->bus = &cxl_bus_type;
+	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
+	dev->type = &cxl_memdev_type;
+	device_set_pm_not_required(dev);
+	INIT_WORK(&cxlmd->detach_work, detach_memdev);
+
+	cdev = &cxlmd->cdev;
+	cdev_init(cdev, fops);
+	return cxlmd;
+
+err:
+	kfree(cxlmd);
+	return ERR_PTR(rc);
+}
+
+static long __cxl_memdev_ioctl(struct cxl_memdev *cxlmd, unsigned int cmd,
+			       unsigned long arg)
+{
+	switch (cmd) {
+	case CXL_MEM_QUERY_COMMANDS:
+		return cxl_query_cmd(cxlmd, (void __user *)arg);
+	case CXL_MEM_SEND_COMMAND:
+		return cxl_send_cmd(cxlmd, (void __user *)arg);
+	default:
+		return -ENOTTY;
+	}
+}
+
+static long cxl_memdev_ioctl(struct file *file, unsigned int cmd,
+			     unsigned long arg)
+{
+	struct cxl_memdev *cxlmd = file->private_data;
+	int rc = -ENXIO;
+
+	down_read(&cxl_memdev_rwsem);
+	if (cxlmd->cxlds)
+		rc = __cxl_memdev_ioctl(cxlmd, cmd, arg);
+	up_read(&cxl_memdev_rwsem);
+
+	return rc;
+}
+
+static int cxl_memdev_open(struct inode *inode, struct file *file)
+{
+	struct cxl_memdev *cxlmd =
+		container_of(inode->i_cdev, typeof(*cxlmd), cdev);
+
+	get_device(&cxlmd->dev);
+	file->private_data = cxlmd;
+
+	return 0;
+}
+
+static int cxl_memdev_release_file(struct inode *inode, struct file *file)
+{
+	struct cxl_memdev *cxlmd =
+		container_of(inode->i_cdev, typeof(*cxlmd), cdev);
+
+	put_device(&cxlmd->dev);
+
+	return 0;
+}
+
+static const struct file_operations cxl_memdev_fops = {
+	.owner = THIS_MODULE,
+	.unlocked_ioctl = cxl_memdev_ioctl,
+	.open = cxl_memdev_open,
+	.release = cxl_memdev_release_file,
+	.compat_ioctl = compat_ptr_ioctl,
+	.llseek = noop_llseek,
+};
+
+struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds)
+{
+	struct cxl_memdev *cxlmd;
+	struct device *dev;
+	struct cdev *cdev;
+	int rc;
+
+	cxlmd = cxl_memdev_alloc(cxlds, &cxl_memdev_fops);
+	if (IS_ERR(cxlmd))
+		return cxlmd;
+
+	dev = &cxlmd->dev;
+	rc = dev_set_name(dev, "mem%d", cxlmd->id);
+	if (rc)
+		goto err;
+
+	/*
+	 * Activate ioctl operations, no cxl_memdev_rwsem manipulation
+	 * needed as this is ordered with cdev_add() publishing the device.
+	 */
+	cxlmd->cxlds = cxlds;
+
+	cdev = &cxlmd->cdev;
+	rc = cdev_device_add(cdev, dev);
+	if (rc)
+		goto err;
+
+	rc = devm_add_action_or_reset(cxlds->dev, cxl_memdev_unregister, cxlmd);
+	if (rc)
+		return ERR_PTR(rc);
+	return cxlmd;
+
+err:
+	/*
+	 * The cdev was briefly live, shutdown any ioctl operations that
+	 * saw that state.
+	 */
+	cxl_memdev_shutdown(dev);
+	put_device(dev);
+	return ERR_PTR(rc);
+}
+EXPORT_SYMBOL_NS_GPL(devm_cxl_add_memdev, CXL);
+
+__init int cxl_memdev_init(void)
+{
+	dev_t devt;
+	int rc;
+
+	rc = alloc_chrdev_region(&devt, 0, CXL_MEM_MAX_DEVS, "cxl");
+	if (rc)
+		return rc;
+
+	cxl_mem_major = MAJOR(devt);
+
+	return 0;
+}
+
+void cxl_memdev_exit(void)
+{
+	unregister_chrdev_region(MKDEV(cxl_mem_major, 0), CXL_MEM_MAX_DEVS);
+}