drivers/staging/unisys/visorchipset/file.c

   1 /* file.c
   2  *
   3  * Copyright (C) 2010 - 2013 UNISYS CORPORATION
   4  * All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or (at
   9  * your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  14  * NON INFRINGEMENT.  See the GNU General Public License for more
  15  * details.
  16  */
  17
  18 /* This contains the implementation that allows a usermode program to
  19  * communicate with the visorchipset driver using a device/file interface.
  20  */
  21
  22 #include "globals.h"
  23 #include "visorchannel.h"
  24 #include <linux/mm.h>
  25 #include <linux/fs.h>
  26 #include "uisutils.h"
  27 #include "file.h"
  28
  29 #define CURRENT_FILE_PC VISOR_CHIPSET_PC_file_c
  30
  31 static struct cdev file_cdev;
  32 static struct visorchannel **file_controlvm_channel;
  33
  34 static int visorchipset_open(struct inode *inode, struct file *file);
  35 static int visorchipset_release(struct inode *inode, struct file *file);
  36 static int visorchipset_mmap(struct file *file, struct vm_area_struct *vma);
  37 static long visorchipset_ioctl(struct file *file, unsigned int cmd,
  38                                 unsigned long arg);
  39
  40 static const struct file_operations visorchipset_fops = {
  41         .owner = THIS_MODULE,
  42         .open = visorchipset_open,
  43         .read = NULL,
  44         .write = NULL,
  45         .unlocked_ioctl = visorchipset_ioctl,
  46         .release = visorchipset_release,
  47         .mmap = visorchipset_mmap,
  48 };
  49
  50 int
  51 visorchipset_file_init(dev_t major_dev, struct visorchannel **controlvm_channel)
  52 {
  53         int rc = 0;
  54
  55         file_controlvm_channel = controlvm_channel;
  56         cdev_init(&file_cdev, &visorchipset_fops);
  57         file_cdev.owner = THIS_MODULE;
  58         if (MAJOR(major_dev) == 0) {
  59                 /* dynamic major device number registration required */
  60                 if (alloc_chrdev_region(&major_dev, 0, 1, MYDRVNAME) < 0)
  61                         return -1;
  62         } else {
  63                 /* static major device number registration required */
  64                 if (register_chrdev_region(major_dev, 1, MYDRVNAME) < 0)
  65                         return -1;
  66         }
  67         rc = cdev_add(&file_cdev, MKDEV(MAJOR(major_dev), 0), 1);
  68         if (rc < 0) {
  69                 unregister_chrdev_region(major_dev, 1);
  70                 return -1;
  71         }
  72         return 0;
  73 }
  74
  75 void
  76 visorchipset_file_cleanup(dev_t major_dev)
  77 {
  78         if (file_cdev.ops != NULL)
  79                 cdev_del(&file_cdev);
  80         file_cdev.ops = NULL;
  81         unregister_chrdev_region(major_dev, 1);
  82 }
  83
  84 static int
  85 visorchipset_open(struct inode *inode, struct file *file)
  86 {
  87         unsigned minor_number = iminor(inode);
  88
  89         if (minor_number != 0)
  90                 return -ENODEV;
  91         file->private_data = NULL;
  92         return 0;
  93 }
  94
  95 static int
  96 visorchipset_release(struct inode *inode, struct file *file)
  97 {
  98         return 0;
  99 }
 100
 101 static int
 102 visorchipset_mmap(struct file *file, struct vm_area_struct *vma)
 103 {
 104         ulong physaddr = 0;
 105         ulong offset = vma->vm_pgoff << PAGE_SHIFT;
 106         GUEST_PHYSICAL_ADDRESS addr = 0;
 107
 108         /* sv_enable_dfp(); */
 109         if (offset & (PAGE_SIZE - 1))
 110                 return -ENXIO;  /* need aligned offsets */
 111
 112         switch (offset) {
 113         case VISORCHIPSET_MMAP_CONTROLCHANOFFSET:
 114                 vma->vm_flags |= VM_IO;
 115                 if (*file_controlvm_channel == NULL) {
 116                         return -ENXIO;
 117                 }
 118                 visorchannel_read(*file_controlvm_channel,
 119                         offsetof(struct spar_controlvm_channel_protocol,
 120                                  gp_control_channel),
 121                         &addr, sizeof(addr));
 122                 if (addr == 0) {
 123                         return -ENXIO;
 124                 }
 125                 physaddr = (ulong)addr;
 126                 if (remap_pfn_range(vma, vma->vm_start,
 127                                     physaddr >> PAGE_SHIFT,
 128                                     vma->vm_end - vma->vm_start,
 129                                     /*pgprot_noncached */
 130                                     (vma->vm_page_prot))) {
 131                         return -EAGAIN;
 132                 }
 133                 break;
 134         default:
 135                 return -ENOSYS;
 136         }
 137         return 0;
 138 }
 139
 140 static long visorchipset_ioctl(struct file *file, unsigned int cmd,
 141                                 unsigned long arg)
 142 {
 143         s64 adjustment;
 144         s64 vrtc_offset;
 145
 146         switch (cmd) {
 147         case VMCALL_QUERY_GUEST_VIRTUAL_TIME_OFFSET:
 148                 /* get the physical rtc offset */
 149                 vrtc_offset = issue_vmcall_query_guest_virtual_time_offset();
 150                 if (copy_to_user
 151                     ((void __user *)arg, &vrtc_offset, sizeof(vrtc_offset))) {
 152                         return -EFAULT;
 153                 }
 154                 return SUCCESS;
 155         case VMCALL_UPDATE_PHYSICAL_TIME:
 156                 if (copy_from_user
 157                     (&adjustment, (void __user *)arg, sizeof(adjustment))) {
 158                         return -EFAULT;
 159                 }
 160                 return issue_vmcall_update_physical_time(adjustment);
 161         default:
 162                 return -EFAULT;
 163         }
 164 }