drivers/dma/idxd/compat.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright(c) 2021 Intel Corporation. All rights rsvd. */
   3 #include <linux/init.h>
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/device.h>
   7 #include <linux/device/bus.h>
   8 #include "idxd.h"
   9
  10 extern int device_driver_attach(struct device_driver *drv, struct device *dev);
  11 extern void device_driver_detach(struct device *dev);
  12
  13 #define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
  14         struct driver_attribute driver_attr_##_name =           \
  15         __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
  16
  17 static ssize_t unbind_store(struct device_driver *drv, const char *buf, size_t count)
  18 {
  19         const struct bus_type *bus = drv->bus;
  20         struct device *dev;
  21         int rc = -ENODEV;
  22
  23         dev = bus_find_device_by_name(bus, NULL, buf);
  24         if (dev && dev->driver) {
  25                 device_driver_detach(dev);
  26                 rc = count;
  27         }
  28
  29         return rc;
  30 }
  31 static DRIVER_ATTR_IGNORE_LOCKDEP(unbind, 0200, NULL, unbind_store);
  32
  33 static ssize_t bind_store(struct device_driver *drv, const char *buf, size_t count)
  34 {
  35         const struct bus_type *bus = drv->bus;
  36         struct device *dev;
  37         struct device_driver *alt_drv = NULL;
  38         int rc = -ENODEV;
  39         struct idxd_dev *idxd_dev;
  40
  41         dev = bus_find_device_by_name(bus, NULL, buf);
  42         if (!dev || dev->driver || drv != &dsa_drv.drv)
  43                 return -ENODEV;
  44
  45         idxd_dev = confdev_to_idxd_dev(dev);
  46         if (is_idxd_dev(idxd_dev)) {
  47                 alt_drv = driver_find("idxd", bus);
  48         } else if (is_idxd_wq_dev(idxd_dev)) {
  49                 struct idxd_wq *wq = confdev_to_wq(dev);
  50
  51                 if (is_idxd_wq_kernel(wq))
  52                         alt_drv = driver_find("dmaengine", bus);
  53                 else if (is_idxd_wq_user(wq))
  54                         alt_drv = driver_find("user", bus);
  55         }
  56         if (!alt_drv)
  57                 return -ENODEV;
  58
  59         rc = device_driver_attach(alt_drv, dev);
  60         if (rc < 0)
  61                 return rc;
  62
  63         return count;
  64 }
  65 static DRIVER_ATTR_IGNORE_LOCKDEP(bind, 0200, NULL, bind_store);
  66
  67 static struct attribute *dsa_drv_compat_attrs[] = {
  68         &driver_attr_bind.attr,
  69         &driver_attr_unbind.attr,
  70         NULL,
  71 };
  72
  73 static const struct attribute_group dsa_drv_compat_attr_group = {
  74         .attrs = dsa_drv_compat_attrs,
  75 };
  76
  77 static const struct attribute_group *dsa_drv_compat_groups[] = {
  78         &dsa_drv_compat_attr_group,
  79         NULL,
  80 };
  81
  82 static int idxd_dsa_drv_probe(struct idxd_dev *idxd_dev)
  83 {
  84         return -ENODEV;
  85 }
  86
  87 static void idxd_dsa_drv_remove(struct idxd_dev *idxd_dev)
  88 {
  89 }
  90
  91 static enum idxd_dev_type dev_types[] = {
  92         IDXD_DEV_NONE,
  93 };
  94
  95 struct idxd_device_driver dsa_drv = {
  96         .name = "dsa",
  97         .probe = idxd_dsa_drv_probe,
  98         .remove = idxd_dsa_drv_remove,
  99         .type = dev_types,
 100         .drv = {
 101                 .suppress_bind_attrs = true,
 102                 .groups = dsa_drv_compat_groups,
 103         },
 104 };
 105
 106 module_idxd_driver(dsa_drv);
 107 MODULE_IMPORT_NS(IDXD);