drivers/sbus/char/flash.c

   1 /* $Id: flash.c,v 1.25 2001/12/21 04:56:16 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/module.h>
   8 #include <linux/types.h>
   9 #include <linux/errno.h>
  10 #include <linux/miscdevice.h>
  11 #include <linux/slab.h>
  12 #include <linux/fcntl.h>
  13 #include <linux/poll.h>
  14 #include <linux/init.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/mm.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 #include <asm/upa.h>
  26
  27 static DEFINE_SPINLOCK(flash_lock);
  28 static struct {
  29         unsigned long read_base;        /* Physical read address */
  30         unsigned long write_base;       /* Physical write address */
  31         unsigned long read_size;        /* Size of read area */
  32         unsigned long write_size;       /* Size of write area */
  33         unsigned long busy;             /* In use? */
  34 } flash;
  35
  36 #define FLASH_MINOR     152
  37
  38 static int
  39 flash_mmap(struct file *file, struct vm_area_struct *vma)
  40 {
  41         unsigned long addr;
  42         unsigned long size;
  43
  44         spin_lock(&flash_lock);
  45         if (flash.read_base == flash.write_base) {
  46                 addr = flash.read_base;
  47                 size = flash.read_size;
  48         } else {
  49                 if ((vma->vm_flags & VM_READ) &&
  50                     (vma->vm_flags & VM_WRITE)) {
  51                         spin_unlock(&flash_lock);
  52                         return -EINVAL;
  53                 }
  54                 if (vma->vm_flags & VM_READ) {
  55                         addr = flash.read_base;
  56                         size = flash.read_size;
  57                 } else if (vma->vm_flags & VM_WRITE) {
  58                         addr = flash.write_base;
  59                         size = flash.write_size;
  60                 } else {
  61                         spin_unlock(&flash_lock);
  62                         return -ENXIO;
  63                 }
  64         }
  65         spin_unlock(&flash_lock);
  66
  67         if ((vma->vm_pgoff << PAGE_SHIFT) > size)
  68                 return -ENXIO;
  69         addr = vma->vm_pgoff + (addr >> PAGE_SHIFT);
  70
  71         if (vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT)) > size)
  72                 size = vma->vm_end - (vma->vm_start + (vma->vm_pgoff << PAGE_SHIFT));
  73
  74         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  75
  76         if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
  77                 return -EAGAIN;
  78
  79         return 0;
  80 }
  81
  82 static long long
  83 flash_llseek(struct file *file, long long offset, int origin)
  84 {
  85         lock_kernel();
  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                         unlock_kernel();
 100                         return -EINVAL;
 101         }
 102         unlock_kernel();
 103         return file->f_pos;
 104 }
 105
 106 static ssize_t
 107 flash_read(struct file * file, char __user * buf,
 108            size_t count, loff_t *ppos)
 109 {
 110         unsigned long p = file->f_pos;
 111         int i;
 112
 113         if (count > flash.read_size - p)
 114                 count = flash.read_size - p;
 115
 116         for (i = 0; i < count; i++) {
 117                 u8 data = upa_readb(flash.read_base + p + i);
 118                 if (put_user(data, buf))
 119                         return -EFAULT;
 120                 buf++;
 121         }
 122
 123         file->f_pos += count;
 124         return count;
 125 }
 126
 127 static int
 128 flash_open(struct inode *inode, struct file *file)
 129 {
 130         if (test_and_set_bit(0, (void *)&flash.busy) != 0)
 131                 return -EBUSY;
 132
 133         return 0;
 134 }
 135
 136 static int
 137 flash_release(struct inode *inode, struct file *file)
 138 {
 139         spin_lock(&flash_lock);
 140         flash.busy = 0;
 141         spin_unlock(&flash_lock);
 142
 143         return 0;
 144 }
 145
 146 static const struct file_operations flash_fops = {
 147         /* no write to the Flash, use mmap
 148          * and play flash dependent tricks.
 149          */
 150         .owner =        THIS_MODULE,
 151         .llseek =       flash_llseek,
 152         .read =         flash_read,
 153         .mmap =         flash_mmap,
 154         .open =         flash_open,
 155         .release =      flash_release,
 156 };
 157
 158 static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
 159
 160 static int __init flash_init(void)
 161 {
 162         struct sbus_bus *sbus;
 163         struct sbus_dev *sdev = NULL;
 164 #ifdef CONFIG_PCI
 165         struct linux_ebus *ebus;
 166         struct linux_ebus_device *edev = NULL;
 167         struct linux_prom_registers regs[2];
 168         int len, nregs;
 169 #endif
 170         int err;
 171
 172         for_all_sbusdev(sdev, sbus) {
 173                 if (!strcmp(sdev->prom_name, "flashprom")) {
 174                         if (sdev->reg_addrs[0].phys_addr == sdev->reg_addrs[1].phys_addr) {
 175                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 176                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 177                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 178                                 flash.write_base = flash.read_base;
 179                                 flash.write_size = flash.read_size;
 180                         } else {
 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 = ((unsigned long)sdev->reg_addrs[1].phys_addr) |
 185                                         (((unsigned long)sdev->reg_addrs[1].which_io)<<32UL);
 186                                 flash.write_size = sdev->reg_addrs[1].reg_size;
 187                         }
 188                         flash.busy = 0;
 189                         break;
 190                 }
 191         }
 192         if (!sdev) {
 193 #ifdef CONFIG_PCI
 194                 const struct linux_prom_registers *ebus_regs;
 195
 196                 for_each_ebus(ebus) {
 197                         for_each_ebusdev(edev, ebus) {
 198                                 if (!strcmp(edev->prom_node->name, "flashprom"))
 199                                         goto ebus_done;
 200                         }
 201                 }
 202         ebus_done:
 203                 if (!edev)
 204                         return -ENODEV;
 205
 206                 ebus_regs = of_get_property(edev->prom_node, "reg", &len);
 207                 if (!ebus_regs || (len % sizeof(regs[0])) != 0) {
 208                         printk("flash: Strange reg property size %d\n", len);
 209                         return -ENODEV;
 210                 }
 211
 212                 nregs = len / sizeof(ebus_regs[0]);
 213
 214                 flash.read_base = edev->resource[0].start;
 215                 flash.read_size = ebus_regs[0].reg_size;
 216
 217                 if (nregs == 1) {
 218                         flash.write_base = edev->resource[0].start;
 219                         flash.write_size = ebus_regs[0].reg_size;
 220                 } else if (nregs == 2) {
 221                         flash.write_base = edev->resource[1].start;
 222                         flash.write_size = ebus_regs[1].reg_size;
 223                 } else {
 224                         printk("flash: Strange number of regs %d\n", nregs);
 225                         return -ENODEV;
 226                 }
 227
 228                 flash.busy = 0;
 229
 230 #else
 231                 return -ENODEV;
 232 #endif
 233         }
 234
 235         printk("OBP Flash: RD %lx[%lx] WR %lx[%lx]\n",
 236                flash.read_base, flash.read_size,
 237                flash.write_base, flash.write_size);
 238
 239         err = misc_register(&flash_dev);
 240         if (err) {
 241                 printk(KERN_ERR "flash: unable to get misc minor\n");
 242                 return err;
 243         }
 244
 245         return 0;
 246 }
 247
 248 static void __exit flash_cleanup(void)
 249 {
 250         misc_deregister(&flash_dev);
 251 }
 252
 253 module_init(flash_init);
 254 module_exit(flash_cleanup);
 255 MODULE_LICENSE("GPL");