drivers/sbus/char/flash.c

   1 /* $Id: flash.c,v 1.1.1.1 2005/04/11 02:50:34 jack 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         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 = 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         if (test_and_set_bit(0, (void *)&flash.busy) != 0)
 129                 return -EBUSY;
 130
 131         return 0;
 132 }
 133
 134 static int
 135 flash_release(struct inode *inode, struct file *file)
 136 {
 137         spin_lock(&flash_lock);
 138         flash.busy = 0;
 139         spin_unlock(&flash_lock);
 140
 141         return 0;
 142 }
 143
 144 static struct file_operations flash_fops = {
 145         /* no write to the Flash, use mmap
 146          * and play flash dependent tricks.
 147          */
 148         owner:          THIS_MODULE,
 149         llseek:         flash_llseek,
 150         read:           flash_read,
 151         mmap:           flash_mmap,
 152         open:           flash_open,
 153         release:        flash_release,
 154 };
 155
 156 static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
 157
 158 EXPORT_NO_SYMBOLS;
 159
 160 static int __init flash_init(void)
 161 {
 162         struct sbus_bus *sbus;
 163         struct sbus_dev *sdev = 0;
 164         struct linux_ebus *ebus;
 165         struct linux_ebus_device *edev = 0;
 166         struct linux_prom_registers regs[2];
 167         int len, err, nregs;
 168
 169         for_all_sbusdev(sdev, sbus) {
 170                 if (!strcmp(sdev->prom_name, "flashprom")) {
 171                         if (sdev->reg_addrs[0].phys_addr == sdev->reg_addrs[1].phys_addr) {
 172                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 173                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 174                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 175                                 flash.write_base = flash.read_base;
 176                                 flash.write_size = flash.read_size;
 177                         } else {
 178                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 179                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 180                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 181                                 flash.write_base = ((unsigned long)sdev->reg_addrs[1].phys_addr) |
 182                                         (((unsigned long)sdev->reg_addrs[1].which_io)<<32UL);
 183                                 flash.write_size = sdev->reg_addrs[1].reg_size;
 184                         }
 185                         flash.busy = 0;
 186                         break;
 187                 }
 188         }
 189         if (!sdev) {
 190 #ifdef CONFIG_PCI
 191                 for_each_ebus(ebus) {
 192                         for_each_ebusdev(edev, ebus) {
 193                                 if (!strcmp(edev->prom_name, "flashprom"))
 194                                         goto ebus_done;
 195                         }
 196                 }
 197         ebus_done:
 198                 if (!edev)
 199                         return -ENODEV;
 200
 201                 len = prom_getproperty(edev->prom_node, "reg", (void *)regs, sizeof(regs));
 202                 if ((len % sizeof(regs[0])) != 0) {
 203                         printk("flash: Strange reg property size %d\n", len);
 204                         return -ENODEV;
 205                 }
 206
 207                 nregs = len / sizeof(regs[0]);
 208
 209                 flash.read_base = edev->resource[0].start;
 210                 flash.read_size = regs[0].reg_size;
 211
 212                 if (nregs == 1) {
 213                         flash.write_base = edev->resource[0].start;
 214                         flash.write_size = regs[0].reg_size;
 215                 } else if (nregs == 2) {
 216                         flash.write_base = edev->resource[1].start;
 217                         flash.write_size = regs[1].reg_size;
 218                 } else {
 219                         printk("flash: Strange number of regs %d\n", nregs);
 220                         return -ENODEV;
 221                 }
 222
 223                 flash.busy = 0;
 224
 225 #else
 226                 return -ENODEV;
 227 #endif
 228         }
 229
 230         printk("OBP Flash: RD %lx[%lx] WR %lx[%lx]\n",
 231                flash.read_base, flash.read_size,
 232                flash.write_base, flash.write_size);
 233
 234         err = misc_register(&flash_dev);
 235         if (err) {
 236                 printk(KERN_ERR "flash: unable to get misc minor\n");
 237                 return err;
 238         }
 239
 240         return 0;
 241 }
 242
 243 static void __exit flash_cleanup(void)
 244 {
 245         misc_deregister(&flash_dev);
 246 }
 247
 248 module_init(flash_init);
 249 module_exit(flash_cleanup);
 250 MODULE_LICENSE("GPL");