drivers/sbus/char/flash.c

   1 /* $Id: flash.c,v 1.24 2001/10/08 22:19:51 davem Exp $
   2  * flash.c: Allow mmap access to the OBP Flash, for OBP updates.
   3  *
   4  * Copyright (C) 1997  Eddie C. Dost  (ecd@skynet.be)
   5  */
   6
   7 #include <linux/config.h>
   8 #include <linux/module.h>
   9 #include <linux/types.h>
  10 #include <linux/errno.h>
  11 #include <linux/miscdevice.h>
  12 #include <linux/slab.h>
  13 #include <linux/fcntl.h>
  14 #include <linux/poll.h>
  15 #include <linux/init.h>
  16 #include <linux/smp_lock.h>
  17 #include <linux/spinlock.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/sbus.h>
  24 #include <asm/ebus.h>
  25
  26 static spinlock_t flash_lock = SPIN_LOCK_UNLOCKED;
  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 << 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         pgprot_val(vma->vm_page_prot) &= ~(_PAGE_CACHE);
  74         pgprot_val(vma->vm_page_prot) |= _PAGE_E;
  75         vma->vm_flags |= (VM_SHM | VM_LOCKED);
  76
  77         if (remap_page_range(vma->vm_start, addr, size, vma->vm_page_prot))
  78                 return -EAGAIN;
  79
  80         return 0;
  81 }
  82
  83 static long long
  84 flash_llseek(struct file *file, long long offset, int origin)
  85 {
  86         switch (origin) {
  87                 case 0:
  88                         file->f_pos = offset;
  89                         break;
  90                 case 1:
  91                         file->f_pos += offset;
  92                         if (file->f_pos > flash.read_size)
  93                                 file->f_pos = flash.read_size;
  94                         break;
  95                 case 2:
  96                         file->f_pos = flash.read_size;
  97                         break;
  98                 default:
  99                         return -EINVAL;
 100         }
 101         return file->f_pos;
 102 }
 103
 104 static ssize_t
 105 flash_read(struct file * file, char * buf,
 106            size_t count, loff_t *ppos)
 107 {
 108         loff_t p = *ppos;
 109         int i;
 110
 111         if (p > flash.read_size)
 112                 return 0;
 113
 114         if (p < 0)
 115                 return -EINVAL;
 116
 117         if (count > flash.read_size - p)
 118                 count = flash.read_size - p;
 119
 120         for (i = 0; i < count; i++) {
 121                 u8 data = readb(flash.read_base + p + i);
 122                 if (put_user(data, buf))
 123                         return -EFAULT;
 124                 buf++;
 125         }
 126
 127         *ppos = p + count;
 128         return count;
 129 }
 130
 131 static int
 132 flash_open(struct inode *inode, struct file *file)
 133 {
 134         if (test_and_set_bit(0, (void *)&flash.busy) != 0)
 135                 return -EBUSY;
 136
 137         return 0;
 138 }
 139
 140 static int
 141 flash_release(struct inode *inode, struct file *file)
 142 {
 143         spin_lock(&flash_lock);
 144         flash.busy = 0;
 145         spin_unlock(&flash_lock);
 146
 147         return 0;
 148 }
 149
 150 static struct file_operations flash_fops = {
 151         /* no write to the Flash, use mmap
 152          * and play flash dependent tricks.
 153          */
 154         owner:          THIS_MODULE,
 155         llseek:         flash_llseek,
 156         read:           flash_read,
 157         mmap:           flash_mmap,
 158         open:           flash_open,
 159         release:        flash_release,
 160 };
 161
 162 static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
 163
 164 EXPORT_NO_SYMBOLS;
 165
 166 static int __init flash_init(void)
 167 {
 168         struct sbus_bus *sbus;
 169         struct sbus_dev *sdev = 0;
 170 #ifdef CONFIG_PCI
 171         struct linux_ebus *ebus;
 172         struct linux_ebus_device *edev = 0;
 173         struct linux_prom_registers regs[2];
 174         int len, nregs;
 175 #endif
 176         int err;
 177
 178         for_all_sbusdev(sdev, sbus) {
 179                 if (!strcmp(sdev->prom_name, "flashprom")) {
 180                         if (sdev->reg_addrs[0].phys_addr == sdev->reg_addrs[1].phys_addr) {
 181                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 182                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 183                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 184                                 flash.write_base = flash.read_base;
 185                                 flash.write_size = flash.read_size;
 186                         } else {
 187                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 188                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 189                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 190                                 flash.write_base = ((unsigned long)sdev->reg_addrs[1].phys_addr) |
 191                                         (((unsigned long)sdev->reg_addrs[1].which_io)<<32UL);
 192                                 flash.write_size = sdev->reg_addrs[1].reg_size;
 193                         }
 194                         flash.busy = 0;
 195                         break;
 196                 }
 197         }
 198         if (!sdev) {
 199 #ifdef CONFIG_PCI
 200                 for_each_ebus(ebus) {
 201                         for_each_ebusdev(edev, ebus) {
 202                                 if (!strcmp(edev->prom_name, "flashprom"))
 203                                         goto ebus_done;
 204                         }
 205                 }
 206         ebus_done:
 207                 if (!edev)
 208                         return -ENODEV;
 209
 210                 len = prom_getproperty(edev->prom_node, "reg", (void *)regs, sizeof(regs));
 211                 if ((len % sizeof(regs[0])) != 0) {
 212                         printk("flash: Strange reg property size %d\n", len);
 213                         return -ENODEV;
 214                 }
 215
 216                 nregs = len / sizeof(regs[0]);
 217
 218                 flash.read_base = edev->resource[0].start;
 219                 flash.read_size = regs[0].reg_size;
 220
 221                 if (nregs == 1) {
 222                         flash.write_base = edev->resource[0].start;
 223                         flash.write_size = regs[0].reg_size;
 224                 } else if (nregs == 2) {
 225                         flash.write_base = edev->resource[1].start;
 226                         flash.write_size = regs[1].reg_size;
 227                 } else {
 228                         printk("flash: Strange number of regs %d\n", nregs);
 229                         return -ENODEV;
 230                 }
 231
 232                 flash.busy = 0;
 233
 234 #else
 235                 return -ENODEV;
 236 #endif
 237         }
 238
 239         printk("OBP Flash: RD %lx[%lx] WR %lx[%lx]\n",
 240                flash.read_base, flash.read_size,
 241                flash.write_base, flash.write_size);
 242
 243         err = misc_register(&flash_dev);
 244         if (err) {
 245                 printk(KERN_ERR "flash: unable to get misc minor\n");
 246                 return err;
 247         }
 248
 249         return 0;
 250 }
 251
 252 static void __exit flash_cleanup(void)
 253 {
 254         misc_deregister(&flash_dev);
 255 }
 256
 257 module_init(flash_init);
 258 module_exit(flash_cleanup);
 259 MODULE_LICENSE("GPL");