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         vma->vm_flags |= (VM_SHM | VM_LOCKED);
  75         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  76
  77         if (io_remap_pfn_range(vma, 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         lock_kernel();
  87         switch (origin) {
  88                 case 0:
  89                         file->f_pos = offset;
  90                         break;
  91                 case 1:
  92                         file->f_pos += offset;
  93                         if (file->f_pos > flash.read_size)
  94                                 file->f_pos = flash.read_size;
  95                         break;
  96                 case 2:
  97                         file->f_pos = flash.read_size;
  98                         break;
  99                 default:
 100                         unlock_kernel();
 101                         return -EINVAL;
 102         }
 103         unlock_kernel();
 104         return file->f_pos;
 105 }
 106
 107 static ssize_t
 108 flash_read(struct file * file, char __user * buf,
 109            size_t count, loff_t *ppos)
 110 {
 111         unsigned long p = file->f_pos;
 112         int i;
 113
 114         if (count > flash.read_size - p)
 115                 count = flash.read_size - p;
 116
 117         for (i = 0; i < count; i++) {
 118                 u8 data = upa_readb(flash.read_base + p + i);
 119                 if (put_user(data, buf))
 120                         return -EFAULT;
 121                 buf++;
 122         }
 123
 124         file->f_pos += count;
 125         return count;
 126 }
 127
 128 static int
 129 flash_open(struct inode *inode, struct file *file)
 130 {
 131         if (test_and_set_bit(0, (void *)&flash.busy) != 0)
 132                 return -EBUSY;
 133
 134         return 0;
 135 }
 136
 137 static int
 138 flash_release(struct inode *inode, struct file *file)
 139 {
 140         spin_lock(&flash_lock);
 141         flash.busy = 0;
 142         spin_unlock(&flash_lock);
 143
 144         return 0;
 145 }
 146
 147 static struct file_operations flash_fops = {
 148         /* no write to the Flash, use mmap
 149          * and play flash dependent tricks.
 150          */
 151         .owner =        THIS_MODULE,
 152         .llseek =       flash_llseek,
 153         .read =         flash_read,
 154         .mmap =         flash_mmap,
 155         .open =         flash_open,
 156         .release =      flash_release,
 157 };
 158
 159 static struct miscdevice flash_dev = { FLASH_MINOR, "flash", &flash_fops };
 160
 161 static int __init flash_init(void)
 162 {
 163         struct sbus_bus *sbus;
 164         struct sbus_dev *sdev = NULL;
 165 #ifdef CONFIG_PCI
 166         struct linux_ebus *ebus;
 167         struct linux_ebus_device *edev = NULL;
 168         struct linux_prom_registers regs[2];
 169         int len, nregs;
 170 #endif
 171         int err;
 172
 173         for_all_sbusdev(sdev, sbus) {
 174                 if (!strcmp(sdev->prom_name, "flashprom")) {
 175                         if (sdev->reg_addrs[0].phys_addr == sdev->reg_addrs[1].phys_addr) {
 176                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 177                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 178                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 179                                 flash.write_base = flash.read_base;
 180                                 flash.write_size = flash.read_size;
 181                         } else {
 182                                 flash.read_base = ((unsigned long)sdev->reg_addrs[0].phys_addr) |
 183                                         (((unsigned long)sdev->reg_addrs[0].which_io)<<32UL);
 184                                 flash.read_size = sdev->reg_addrs[0].reg_size;
 185                                 flash.write_base = ((unsigned long)sdev->reg_addrs[1].phys_addr) |
 186                                         (((unsigned long)sdev->reg_addrs[1].which_io)<<32UL);
 187                                 flash.write_size = sdev->reg_addrs[1].reg_size;
 188                         }
 189                         flash.busy = 0;
 190                         break;
 191                 }
 192         }
 193         if (!sdev) {
 194 #ifdef CONFIG_PCI
 195                 for_each_ebus(ebus) {
 196                         for_each_ebusdev(edev, ebus) {
 197                                 if (!strcmp(edev->prom_name, "flashprom"))
 198                                         goto ebus_done;
 199                         }
 200                 }
 201         ebus_done:
 202                 if (!edev)
 203                         return -ENODEV;
 204
 205                 len = prom_getproperty(edev->prom_node, "reg", (void *)regs, sizeof(regs));
 206                 if ((len % sizeof(regs[0])) != 0) {
 207                         printk("flash: Strange reg property size %d\n", len);
 208                         return -ENODEV;
 209                 }
 210
 211                 nregs = len / sizeof(regs[0]);
 212
 213                 flash.read_base = edev->resource[0].start;
 214                 flash.read_size = regs[0].reg_size;
 215
 216                 if (nregs == 1) {
 217                         flash.write_base = edev->resource[0].start;
 218                         flash.write_size = regs[0].reg_size;
 219                 } else if (nregs == 2) {
 220                         flash.write_base = edev->resource[1].start;
 221                         flash.write_size = regs[1].reg_size;
 222                 } else {
 223                         printk("flash: Strange number of regs %d\n", nregs);
 224                         return -ENODEV;
 225                 }
 226
 227                 flash.busy = 0;
 228
 229 #else
 230                 return -ENODEV;
 231 #endif
 232         }
 233
 234         printk("OBP Flash: RD %lx[%lx] WR %lx[%lx]\n",
 235                flash.read_base, flash.read_size,
 236                flash.write_base, flash.write_size);
 237
 238         err = misc_register(&flash_dev);
 239         if (err) {
 240                 printk(KERN_ERR "flash: unable to get misc minor\n");
 241                 return err;
 242         }
 243
 244         return 0;
 245 }
 246
 247 static void __exit flash_cleanup(void)
 248 {
 249         misc_deregister(&flash_dev);
 250 }
 251
 252 module_init(flash_init);
 253 module_exit(flash_cleanup);
 254 MODULE_LICENSE("GPL");