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