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/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 #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         pgprot_val(vma->vm_page_prot) &= ~(_PAGE_CACHE);
  75         pgprot_val(vma->vm_page_prot) |= _PAGE_E;
  76         vma->vm_flags |= (VM_SHM | VM_LOCKED);
  77
  78         if (io_remap_pfn_range(vma, vma->vm_start, addr, size, vma->vm_page_prot))
  79                 return -EAGAIN;
  80
  81         return 0;
  82 }
  83
  84 static long long
  85 flash_llseek(struct file *file, long long offset, int origin)
  86 {
  87         lock_kernel();
  88         switch (origin) {
  89                 case 0:
  90                         file->f_pos = offset;
  91                         break;
  92                 case 1:
  93                         file->f_pos += offset;
  94                         if (file->f_pos > flash.read_size)
  95                                 file->f_pos = flash.read_size;
  96                         break;
  97                 case 2:
  98                         file->f_pos = flash.read_size;
  99                         break;
 100                 default:
 101                         unlock_kernel();
 102                         return -EINVAL;
 103         }
 104         unlock_kernel();
 105         return file->f_pos;
 106 }
 107
 108 static ssize_t
 109 flash_read(struct file * file, char __user * buf,
 110            size_t count, loff_t *ppos)
 111 {
 112         unsigned long p = file->f_pos;
 113         int i;
 114
 115         if (count > flash.read_size - p)
 116                 count = flash.read_size - p;
 117
 118         for (i = 0; i < count; i++) {
 119                 u8 data = upa_readb(flash.read_base + p + i);
 120                 if (put_user(data, buf))
 121                         return -EFAULT;
 122                 buf++;
 123         }
 124
 125         file->f_pos += count;
 126         return count;
 127 }
 128
 129 static int
 130 flash_open(struct inode *inode, struct file *file)
 131 {
 132         if (test_and_set_bit(0, (void *)&flash.busy) != 0)
 133                 return -EBUSY;
 134
 135         return 0;
 136 }
 137
 138 static int
 139 flash_release(struct inode *inode, struct file *file)
 140 {
 141         spin_lock(&flash_lock);
 142         flash.busy = 0;
 143         spin_unlock(&flash_lock);
 144
 145         return 0;
 146 }
 147
 148 static struct file_operations flash_fops = {
 149         /* no write to the Flash, use mmap
 150          * and play flash dependent tricks.
 151          */
 152         .owner =        THIS_MODULE,
 153         .llseek =       flash_llseek,
 154         .read =         flash_read,
 155         .mmap =         flash_mmap,
 156         .open =         flash_open,
 157         .release =      flash_release,
 158 };
 159
 160 static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
 161
 162 static int __init flash_init(void)
 163 {
 164         struct sbus_bus *sbus;
 165         struct sbus_dev *sdev = NULL;
 166 #ifdef CONFIG_PCI
 167         struct linux_ebus *ebus;
 168         struct linux_ebus_device *edev = NULL;
 169         struct linux_prom_registers regs[2];
 170         int len, nregs;
 171 #endif
 172         int err;
 173
 174         for_all_sbusdev(sdev, sbus) {
 175                 if (!strcmp(sdev->prom_name, "flashprom")) {
 176                         if (sdev->reg_addrs[0].phys_addr == sdev->reg_addrs[1].phys_addr) {
 177                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 178                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 179                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 180                                 flash.write_base = flash.read_base;
 181                                 flash.write_size = flash.read_size;
 182                         } else {
 183                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 184                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 185                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 186                                 flash.write_base = ((unsigned long)sdev->reg_addrs[1].phys_addr) |
 187                                         (((unsigned long)sdev->reg_addrs[1].which_io)<<32UL);
 188                                 flash.write_size = sdev->reg_addrs[1].reg_size;
 189                         }
 190                         flash.busy = 0;
 191                         break;
 192                 }
 193         }
 194         if (!sdev) {
 195 #ifdef CONFIG_PCI
 196                 for_each_ebus(ebus) {
 197                         for_each_ebusdev(edev, ebus) {
 198                                 if (!strcmp(edev->prom_name, "flashprom"))
 199                                         goto ebus_done;
 200                         }
 201                 }
 202         ebus_done:
 203                 if (!edev)
 204                         return -ENODEV;
 205
 206                 len = prom_getproperty(edev->prom_node, "reg", (void *)regs, sizeof(regs));
 207                 if ((len % sizeof(regs[0])) != 0) {
 208                         printk("flash: Strange reg property size %d\n", len);
 209                         return -ENODEV;
 210                 }
 211
 212                 nregs = len / sizeof(regs[0]);
 213
 214                 flash.read_base = edev->resource[0].start;
 215                 flash.read_size = regs[0].reg_size;
 216
 217                 if (nregs == 1) {
 218                         flash.write_base = edev->resource[0].start;
 219                         flash.write_size = regs[0].reg_size;
 220                 } else if (nregs == 2) {
 221                         flash.write_base = edev->resource[1].start;
 222                         flash.write_size = 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");