drivers/dma/idxd/cdev.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright(c) 2019 Intel Corporation. All rights rsvd. */
   3 #include <linux/init.h>
   4 #include <linux/kernel.h>
   5 #include <linux/module.h>
   6 #include <linux/pci.h>
   7 #include <linux/device.h>
   8 #include <linux/sched/task.h>
   9 #include <linux/intel-svm.h>
  10 #include <linux/io-64-nonatomic-lo-hi.h>
  11 #include <linux/cdev.h>
  12 #include <linux/fs.h>
  13 #include <linux/poll.h>
  14 #include <uapi/linux/idxd.h>
  15 #include "registers.h"
  16 #include "idxd.h"
  17
  18 struct idxd_cdev_context {
  19         const char *name;
  20         dev_t devt;
  21         struct ida minor_ida;
  22 };
  23
  24 /*
  25  * ictx is an array based off of accelerator types. enum idxd_type
  26  * is used as index
  27  */
  28 static struct idxd_cdev_context ictx[IDXD_TYPE_MAX] = {
  29         { .name = "dsa" },
  30 };
  31
  32 struct idxd_user_context {
  33         struct idxd_wq *wq;
  34         struct task_struct *task;
  35         unsigned int flags;
  36 };
  37
  38 enum idxd_cdev_cleanup {
  39         CDEV_NORMAL = 0,
  40         CDEV_FAILED,
  41 };
  42
  43 static void idxd_cdev_dev_release(struct device *dev)
  44 {
  45         dev_dbg(dev, "releasing cdev device\n");
  46         kfree(dev);
  47 }
  48
  49 static struct device_type idxd_cdev_device_type = {
  50         .name = "idxd_cdev",
  51         .release = idxd_cdev_dev_release,
  52 };
  53
  54 static inline struct idxd_cdev *inode_idxd_cdev(struct inode *inode)
  55 {
  56         struct cdev *cdev = inode->i_cdev;
  57
  58         return container_of(cdev, struct idxd_cdev, cdev);
  59 }
  60
  61 static inline struct idxd_wq *idxd_cdev_wq(struct idxd_cdev *idxd_cdev)
  62 {
  63         return container_of(idxd_cdev, struct idxd_wq, idxd_cdev);
  64 }
  65
  66 static inline struct idxd_wq *inode_wq(struct inode *inode)
  67 {
  68         return idxd_cdev_wq(inode_idxd_cdev(inode));
  69 }
  70
  71 static int idxd_cdev_open(struct inode *inode, struct file *filp)
  72 {
  73         struct idxd_user_context *ctx;
  74         struct idxd_device *idxd;
  75         struct idxd_wq *wq;
  76         struct device *dev;
  77         struct idxd_cdev *idxd_cdev;
  78
  79         wq = inode_wq(inode);
  80         idxd = wq->idxd;
  81         dev = &idxd->pdev->dev;
  82         idxd_cdev = &wq->idxd_cdev;
  83
  84         dev_dbg(dev, "%s called: %d\n", __func__, idxd_wq_refcount(wq));
  85
  86         if (idxd_wq_refcount(wq) > 0 && wq_dedicated(wq))
  87                 return -EBUSY;
  88
  89         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
  90         if (!ctx)
  91                 return -ENOMEM;
  92
  93         ctx->wq = wq;
  94         filp->private_data = ctx;
  95         idxd_wq_get(wq);
  96         return 0;
  97 }
  98
  99 static int idxd_cdev_release(struct inode *node, struct file *filep)
 100 {
 101         struct idxd_user_context *ctx = filep->private_data;
 102         struct idxd_wq *wq = ctx->wq;
 103         struct idxd_device *idxd = wq->idxd;
 104         struct device *dev = &idxd->pdev->dev;
 105
 106         dev_dbg(dev, "%s called\n", __func__);
 107         filep->private_data = NULL;
 108
 109         kfree(ctx);
 110         idxd_wq_put(wq);
 111         return 0;
 112 }
 113
 114 static int check_vma(struct idxd_wq *wq, struct vm_area_struct *vma,
 115                      const char *func)
 116 {
 117         struct device *dev = &wq->idxd->pdev->dev;
 118
 119         if ((vma->vm_end - vma->vm_start) > PAGE_SIZE) {
 120                 dev_info_ratelimited(dev,
 121                                      "%s: %s: mapping too large: %lu\n",
 122                                      current->comm, func,
 123                                      vma->vm_end - vma->vm_start);
 124                 return -EINVAL;
 125         }
 126
 127         return 0;
 128 }
 129
 130 static int idxd_cdev_mmap(struct file *filp, struct vm_area_struct *vma)
 131 {
 132         struct idxd_user_context *ctx = filp->private_data;
 133         struct idxd_wq *wq = ctx->wq;
 134         struct idxd_device *idxd = wq->idxd;
 135         struct pci_dev *pdev = idxd->pdev;
 136         phys_addr_t base = pci_resource_start(pdev, IDXD_WQ_BAR);
 137         unsigned long pfn;
 138         int rc;
 139
 140         dev_dbg(&pdev->dev, "%s called\n", __func__);
 141         rc = check_vma(wq, vma, __func__);
 142
 143         vma->vm_flags |= VM_DONTCOPY;
 144         pfn = (base + idxd_get_wq_portal_full_offset(wq->id,
 145                                 IDXD_PORTAL_LIMITED)) >> PAGE_SHIFT;
 146         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 147         vma->vm_private_data = ctx;
 148
 149         return io_remap_pfn_range(vma, vma->vm_start, pfn, PAGE_SIZE,
 150                         vma->vm_page_prot);
 151 }
 152
 153 static __poll_t idxd_cdev_poll(struct file *filp,
 154                                struct poll_table_struct *wait)
 155 {
 156         struct idxd_user_context *ctx = filp->private_data;
 157         struct idxd_wq *wq = ctx->wq;
 158         struct idxd_device *idxd = wq->idxd;
 159         struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
 160         unsigned long flags;
 161         __poll_t out = 0;
 162
 163         poll_wait(filp, &idxd_cdev->err_queue, wait);
 164         spin_lock_irqsave(&idxd->dev_lock, flags);
 165         if (idxd->sw_err.valid)
 166                 out = EPOLLIN | EPOLLRDNORM;
 167         spin_unlock_irqrestore(&idxd->dev_lock, flags);
 168
 169         return out;
 170 }
 171
 172 static const struct file_operations idxd_cdev_fops = {
 173         .owner = THIS_MODULE,
 174         .open = idxd_cdev_open,
 175         .release = idxd_cdev_release,
 176         .mmap = idxd_cdev_mmap,
 177         .poll = idxd_cdev_poll,
 178 };
 179
 180 int idxd_cdev_get_major(struct idxd_device *idxd)
 181 {
 182         return MAJOR(ictx[idxd->type].devt);
 183 }
 184
 185 static int idxd_wq_cdev_dev_setup(struct idxd_wq *wq)
 186 {
 187         struct idxd_device *idxd = wq->idxd;
 188         struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
 189         struct idxd_cdev_context *cdev_ctx;
 190         struct device *dev;
 191         int minor, rc;
 192
 193         idxd_cdev->dev = kzalloc(sizeof(*idxd_cdev->dev), GFP_KERNEL);
 194         if (!idxd_cdev->dev)
 195                 return -ENOMEM;
 196
 197         dev = idxd_cdev->dev;
 198         dev->parent = &idxd->pdev->dev;
 199         dev_set_name(dev, "%s/wq%u.%u", idxd_get_dev_name(idxd),
 200                      idxd->id, wq->id);
 201         dev->bus = idxd_get_bus_type(idxd);
 202
 203         cdev_ctx = &ictx[wq->idxd->type];
 204         minor = ida_simple_get(&cdev_ctx->minor_ida, 0, MINORMASK, GFP_KERNEL);
 205         if (minor < 0) {
 206                 rc = minor;
 207                 kfree(dev);
 208                 goto ida_err;
 209         }
 210
 211         dev->devt = MKDEV(MAJOR(cdev_ctx->devt), minor);
 212         dev->type = &idxd_cdev_device_type;
 213         rc = device_register(dev);
 214         if (rc < 0) {
 215                 dev_err(&idxd->pdev->dev, "device register failed\n");
 216                 goto dev_reg_err;
 217         }
 218         idxd_cdev->minor = minor;
 219
 220         return 0;
 221
 222  dev_reg_err:
 223         ida_simple_remove(&cdev_ctx->minor_ida, MINOR(dev->devt));
 224         put_device(dev);
 225  ida_err:
 226         idxd_cdev->dev = NULL;
 227         return rc;
 228 }
 229
 230 static void idxd_wq_cdev_cleanup(struct idxd_wq *wq,
 231                                  enum idxd_cdev_cleanup cdev_state)
 232 {
 233         struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
 234         struct idxd_cdev_context *cdev_ctx;
 235
 236         cdev_ctx = &ictx[wq->idxd->type];
 237         if (cdev_state == CDEV_NORMAL)
 238                 cdev_del(&idxd_cdev->cdev);
 239         device_unregister(idxd_cdev->dev);
 240         /*
 241          * The device_type->release() will be called on the device and free
 242          * the allocated struct device. We can just forget it.
 243          */
 244         ida_simple_remove(&cdev_ctx->minor_ida, idxd_cdev->minor);
 245         idxd_cdev->dev = NULL;
 246         idxd_cdev->minor = -1;
 247 }
 248
 249 int idxd_wq_add_cdev(struct idxd_wq *wq)
 250 {
 251         struct idxd_cdev *idxd_cdev = &wq->idxd_cdev;
 252         struct cdev *cdev = &idxd_cdev->cdev;
 253         struct device *dev;
 254         int rc;
 255
 256         rc = idxd_wq_cdev_dev_setup(wq);
 257         if (rc < 0)
 258                 return rc;
 259
 260         dev = idxd_cdev->dev;
 261         cdev_init(cdev, &idxd_cdev_fops);
 262         cdev_set_parent(cdev, &dev->kobj);
 263         rc = cdev_add(cdev, dev->devt, 1);
 264         if (rc) {
 265                 dev_dbg(&wq->idxd->pdev->dev, "cdev_add failed: %d\n", rc);
 266                 idxd_wq_cdev_cleanup(wq, CDEV_FAILED);
 267                 return rc;
 268         }
 269
 270         init_waitqueue_head(&idxd_cdev->err_queue);
 271         return 0;
 272 }
 273
 274 void idxd_wq_del_cdev(struct idxd_wq *wq)
 275 {
 276         idxd_wq_cdev_cleanup(wq, CDEV_NORMAL);
 277 }
 278
 279 int idxd_cdev_register(void)
 280 {
 281         int rc, i;
 282
 283         for (i = 0; i < IDXD_TYPE_MAX; i++) {
 284                 ida_init(&ictx[i].minor_ida);
 285                 rc = alloc_chrdev_region(&ictx[i].devt, 0, MINORMASK,
 286                                          ictx[i].name);
 287                 if (rc)
 288                         return rc;
 289         }
 290
 291         return 0;
 292 }
 293
 294 void idxd_cdev_remove(void)
 295 {
 296         int i;
 297
 298         for (i = 0; i < IDXD_TYPE_MAX; i++) {
 299                 unregister_chrdev_region(ictx[i].devt, MINORMASK);
 300                 ida_destroy(&ictx[i].minor_ida);
 301         }
 302 }