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/mutex.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_MUTEX(flash_mutex);
  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         mutex_lock(&flash_mutex);
  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                         mutex_unlock(&flash_mutex);
  99                         return -EINVAL;
 100         }
 101         mutex_unlock(&flash_mutex);
 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         loff_t p = *ppos;
 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         *ppos += count;
 123         return count;
 124 }
 125
 126 static int
 127 flash_open(struct inode *inode, struct file *file)
 128 {
 129         mutex_lock(&flash_mutex);
 130         if (test_and_set_bit(0, (void *)&flash.busy) != 0) {
 131                 mutex_unlock(&flash_mutex);
 132                 return -EBUSY;
 133         }
 134
 135         mutex_unlock(&flash_mutex);
 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 platform_device *op)
 164 {
 165         struct device_node *dp = op->dev.of_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->dev.of_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 platform_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 platform_driver flash_driver = {
 210         .driver = {
 211                 .name = "flash",
 212                 .owner = THIS_MODULE,
 213                 .of_match_table = flash_match,
 214         },
 215         .probe          = flash_probe,
 216         .remove         = __devexit_p(flash_remove),
 217 };
 218
 219 module_platform_driver(flash_driver);
 220
 221 MODULE_LICENSE("GPL");