diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/cxl/core/memdev.c | 386 |
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); +} |