drivers/sbus/char/flash.c

   1 /* flash.c: Allow mmap access to the OBP Flash, for OBP updates.
   2  *
   3  * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/types.h>
   8 #include <linux/errno.h>
   9 #include <linux/miscdevice.h>
  10 #include <linux/fcntl.h>
  11 #include <linux/poll.h>
  12 #include <linux/init.h>
  13 #include <linux/smp_lock.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/mm.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18
  19 #include <asm/system.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/pgtable.h>
  22 #include <asm/io.h>
  23 #include <asm/upa.h>
  24
  25 static DEFINE_SPINLOCK(flash_lock);
  26 static struct {
  27         unsigned long read_base;        /* Physical read address */
  28         unsigned long write_base;       /* Physical write address */
  29         unsigned long read_size;        /* Size of read area */
  30         unsigned long write_size;       /* Size of write area */
  31         unsigned long busy;             /* In use? */
  32 } flash;
  33
  34 #define FLASH_MINOR     152
  35
  36 static int
  37 flash_mmap(struct file *file, struct vm_area_struct *vma)
  38 {
  39         unsigned long addr;
  40         unsigned long size;
  41
  42         spin_lock(&flash_lock);
  43         if (flash.read_base == flash.write_base) {
  44                 addr = flash.read_base;
  45                 size = flash.read_size;
  46         } else {
  47                 if ((vma->vm_flags & VM_READ) &&
  48                     (vma->vm_flags & VM_WRITE)) {
  49                         spin_unlock(&flash_lock);
  50                         return -EINVAL;
  51                 }
  52                 if (vma->vm_flags & VM_READ) {
  53                         addr = flash.read_base;
  54                         size = flash.read_size;
  55                 } else if (vma->vm_flags & VM_WRITE) {
  56                         addr = flash.write_base;
  57                         size = flash.write_size;
  58                 } else {
  59                         spin_unlock(&flash_lock);
  60                         return -ENXIO;
  61                 }
  62         }
  63         spin_unlock(&flash_lock);
  64
  65         if ((vma->vm_pgoff << PAGE_SHIFT) > size)
  66                 return -ENXIO;
  67         addr = vma->vm_pgoff + (addr >> PAGE_SHIFT);
  68
  69         if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
  70                 size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));
  71
  72         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  73
  74         if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
  75                 return -EAGAIN;
  76
  77         return 0;
  78 }
  79
  80 static long long
  81 flash_llseek(struct file *file, long long offset, int origin)
  82 {
  83         lock_kernel();
  84         switch (origin) {
  85                 case 0:
  86                         file->f_pos = offset;
  87                         break;
  88                 case 1:
  89                         file->f_pos += offset;
  90                         if (file->f_pos > flash.read_size)
  91                                 file->f_pos = flash.read_size;
  92                         break;
  93                 case 2:
  94                         file->f_pos = flash.read_size;
  95                         break;
  96                 default:
  97                         unlock_kernel();
  98                         return -EINVAL;
  99         }
 100         unlock_kernel();
 101         return file->f_pos;
 102 }
 103
 104 static ssize_t
 105 flash_read(struct file * file, char __user * buf,
 106            size_t count, loff_t *ppos)
 107 {
 108         unsigned long p = file->f_pos;
 109         int i;
 110
 111         if (count > flash.read_size - p)
 112                 count = flash.read_size - p;
 113
 114         for (i = 0; i < count; i++) {
 115                 u8 data = upa_readb(flash.read_base + p + i);
 116                 if (put_user(data, buf))
 117                         return -EFAULT;
 118                 buf++;
 119         }
 120
 121         file->f_pos += count;
 122         return count;
 123 }
 124
 125 static int
 126 flash_open(struct inode *inode, struct file *file)
 127 {
 128         lock_kernel();
 129         if (test_and_set_bit(0, (void *)&flash.busy) != 0) {
 130                 unlock_kernel();
 131                 return -EBUSY;
 132         }
 133
 134         unlock_kernel();
 135         return 0;
 136 }
 137
 138 static int
 139 flash_release(struct inode *inode, struct file *file)
 140 {
 141         spin_lock(&flash_lock);
 142         flash.busy = 0;
 143         spin_unlock(&flash_lock);
 144
 145         return 0;
 146 }
 147
 148 static const struct file_operations flash_fops = {
 149         /* no write to the Flash, use mmap
 150          * and play flash dependent tricks.
 151          */
 152         .owner =        THIS_MODULE,
 153         .llseek =       flash_llseek,
 154         .read =         flash_read,
 155         .mmap =         flash_mmap,
 156         .open =         flash_open,
 157         .release =      flash_release,
 158 };
 159
 160 static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
 161
 162 static int __devinit flash_probe(struct of_device *op,
 163                                  const struct of_device_id *match)
 164 {
 165         struct device_node *dp = op->node;
 166         struct device_node *parent;
 167
 168         parent = dp->parent;
 169
 170         if (strcmp(parent->name, "sbus") &&
 171             strcmp(parent->name, "sbi") &&
 172             strcmp(parent->name, "ebus"))
 173                 return -ENODEV;
 174
 175         flash.read_base = op->resource[0].start;
 176         flash.read_size = resource_size(&op->resource[0]);
 177         if (op->resource[1].flags) {
 178                 flash.write_base = op->resource[1].start;
 179                 flash.write_size = resource_size(&op->resource[1]);
 180         } else {
 181                 flash.write_base = op->resource[0].start;
 182                 flash.write_size = resource_size(&op->resource[0]);
 183         }
 184         flash.busy = 0;
 185
 186         printk(KERN_INFO "%s: OBP Flash, RD %lx[%lx] WR %lx[%lx]\n",
 187                op->node->full_name,
 188                flash.read_base, flash.read_size,
 189                flash.write_base, flash.write_size);
 190
 191         return misc_register(&flash_dev);
 192 }
 193
 194 static int __devexit flash_remove(struct of_device *op)
 195 {
 196         misc_deregister(&flash_dev);
 197
 198         return 0;
 199 }
 200
 201 static const struct of_device_id flash_match[] = {
 202         {
 203                 .name = "flashprom",
 204         },
 205         {},
 206 };
 207 MODULE_DEVICE_TABLE(of, flash_match);
 208
 209 static struct of_platform_driver flash_driver = {
 210         .name           = "flash",
 211         .match_table    = flash_match,
 212         .probe          = flash_probe,
 213         .remove         = __devexit_p(flash_remove),
 214 };
 215
 216 static int __init flash_init(void)
 217 {
 218         return of_register_driver(&flash_driver, &of_bus_type);
 219 }
 220
 221 static void __exit flash_cleanup(void)
 222 {
 223         of_unregister_driver(&flash_driver);
 224 }
 225
 226 module_init(flash_init);
 227 module_exit(flash_cleanup);
 228 MODULE_LICENSE("GPL");