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 static dev_t majordev = -1; /**< indicates major num for device */
  34
  35 static int visorchipset_open(struct inode *inode, struct file *file);
  36 static int visorchipset_release(struct inode *inode, struct file *file);
  37 static int visorchipset_mmap(struct file *file, struct vm_area_struct *vma);
  38 static long visorchipset_ioctl(struct file *file, unsigned int cmd,
  39                                 unsigned long arg);
  40
  41 static const struct file_operations visorchipset_fops = {
  42         .owner = THIS_MODULE,
  43         .open = visorchipset_open,
  44         .read = NULL,
  45         .write = NULL,
  46         .unlocked_ioctl = visorchipset_ioctl,
  47         .release = visorchipset_release,
  48         .mmap = visorchipset_mmap,
  49 };
  50
  51 int
  52 visorchipset_file_init(dev_t major_dev, struct visorchannel **controlvm_channel)
  53 {
  54         int rc = 0;
  55
  56         file_controlvm_channel = controlvm_channel;
  57         majordev = major_dev;
  58         cdev_init(&file_cdev, &visorchipset_fops);
  59         file_cdev.owner = THIS_MODULE;
  60         if (MAJOR(major_dev) == 0) {
  61                 /* dynamic major device number registration required */
  62                 if (alloc_chrdev_region(&major_dev, 0, 1, MYDRVNAME) < 0)
  63                         return -1;
  64         } else {
  65                 /* static major device number registration required */
  66                 if (register_chrdev_region(major_dev, 1, MYDRVNAME) < 0)
  67                         return -1;
  68         }
  69         rc = cdev_add(&file_cdev, MKDEV(MAJOR(major_dev), 0), 1);
  70         if (rc  < 0)
  71                 return -1;
  72         return 0;
  73 }
  74
  75 void
  76 visorchipset_file_cleanup(void)
  77 {
  78         if (file_cdev.ops != NULL)
  79                 cdev_del(&file_cdev);
  80         file_cdev.ops = NULL;
  81         if (MAJOR(majordev) >= 0) {
  82                 unregister_chrdev_region(majordev, 1);
  83                 majordev = MKDEV(0, 0);
  84         }
  85 }
  86
  87 static int
  88 visorchipset_open(struct inode *inode, struct file *file)
  89 {
  90         unsigned minor_number = iminor(inode);
  91
  92         if (minor_number != 0)
  93                 return -ENODEV;
  94         file->private_data = NULL;
  95         return 0;
  96 }
  97
  98 static int
  99 visorchipset_release(struct inode *inode, struct file *file)
 100 {
 101         return 0;
 102 }
 103
 104 static int
 105 visorchipset_mmap(struct file *file, struct vm_area_struct *vma)
 106 {
 107         ulong physaddr = 0;
 108         ulong offset = vma->vm_pgoff << PAGE_SHIFT;
 109         GUEST_PHYSICAL_ADDRESS addr = 0;
 110
 111         /* sv_enable_dfp(); */
 112         if (offset & (PAGE_SIZE - 1))
 113                 return -ENXIO;  /* need aligned offsets */
 114
 115         switch (offset) {
 116         case VISORCHIPSET_MMAP_CONTROLCHANOFFSET:
 117                 vma->vm_flags |= VM_IO;
 118                 if (*file_controlvm_channel == NULL) {
 119                         return -ENXIO;
 120                 }
 121                 visorchannel_read(*file_controlvm_channel,
 122                         offsetof(struct spar_controlvm_channel_protocol,
 123                                  gp_control_channel),
 124                         &addr, sizeof(addr));
 125                 if (addr == 0) {
 126                         return -ENXIO;
 127                 }
 128                 physaddr = (ulong)addr;
 129                 if (remap_pfn_range(vma, vma->vm_start,
 130                                     physaddr >> PAGE_SHIFT,
 131                                     vma->vm_end - vma->vm_start,
 132                                     /*pgprot_noncached */
 133                                     (vma->vm_page_prot))) {
 134                         return -EAGAIN;
 135                 }
 136                 break;
 137         default:
 138                 return -ENOSYS;
 139         }
 140         return 0;
 141 }
 142
 143 static long visorchipset_ioctl(struct file *file, unsigned int cmd,
 144                                 unsigned long arg)
 145 {
 146         s64 adjustment;
 147         s64 vrtc_offset;
 148
 149         switch (cmd) {
 150         case VMCALL_QUERY_GUEST_VIRTUAL_TIME_OFFSET:
 151                 /* get the physical rtc offset */
 152                 vrtc_offset = issue_vmcall_query_guest_virtual_time_offset();
 153                 if (copy_to_user
 154                     ((void __user *)arg, &vrtc_offset, sizeof(vrtc_offset))) {
 155                         return -EFAULT;
 156                 }
 157                 return SUCCESS;
 158         case VMCALL_UPDATE_PHYSICAL_TIME:
 159                 if (copy_from_user
 160                     (&adjustment, (void __user *)arg, sizeof(adjustment))) {
 161                         return -EFAULT;
 162                 }
 163                 return issue_vmcall_update_physical_time(adjustment);
 164         default:
 165                 return -EFAULT;
 166         }
 167 }