jedec.c

linux-2.6.15.6

   // Wait for any write/erase operation to settle
   OldVal = flread(base);
   for (I = 0; OldVal != flread(base) && I < 10000; I++)
      OldVal = flread(base);

   // Reset the chip
   flwrite(Reset,0x555);

   // Send the sequence
   flwrite(AutoSel1,0x555);
   flwrite(AutoSel2,0x2AA);
   flwrite(AutoSel3,0x555);

   // Test #1, JEDEC numbers are readable from 0x??00/0x??01
   if (flread(0) != flread(0x100) ||
       flread(1) != flread(0x101))
   {
      flwrite(Reset,0x555);
      return 0;
   }

   // Split up the JEDEC numbers
   OldVal = flread(0);
   for (I = 0; I != 4; I++)
      Mfg[I] = (OldVal >> (I*8));
   OldVal = flread(1);
   for (I = 0; I != 4; I++)
      Id[I] = (OldVal >> (I*8));

   Size = handle_jedecs(map,Mfg,Id,4,base,priv);
   if (Size == 0)
   {
      flwrite(Reset,0x555);
      return 0;
   }

   /* Check if there is address wrap around within a single bank, if this
      returns JEDEC numbers then we assume that it is wrap around. Notice
      we call this routine with the JEDEC return still enabled, if two or
      more flashes have a truncated address space the probe test will still
      work */
   if (base + (Size<<2)+0x555 < map->size &&
       base + (Size<<2)+0x555 < (base & (~(my_bank_size-1))) + my_bank_size)
   {
      if (flread(base+Size) != flread(base+Size + 0x100) ||
	  flread(base+Size + 1) != flread(base+Size + 0x101))
      {
	 jedec_probe32(map,base+Size,priv);
      }
   }

   // Reset.
   flwrite(0xF0F0F0F0,0x555);

   return 1;

   #undef flread
   #undef flwrite
}

/* Linear read. */
static int jedec_read(struct mtd_info *mtd, loff_t from, size_t len,
		      size_t *retlen, u_char *buf)
{
   struct map_info *map = mtd->priv;

   map_copy_from(map, buf, from, len);
   *retlen = len;
   return 0;
}

/* Banked read. Take special care to jump past the holes in the bank
   mapping. This version assumes symetry in the holes.. */
static int jedec_read_banked(struct mtd_info *mtd, loff_t from, size_t len,
			     size_t *retlen, u_char *buf)
{
   struct map_info *map = mtd->priv;
   struct jedec_private *priv = map->fldrv_priv;

   *retlen = 0;
   while (len > 0)
   {
      // Determine what bank and offset into that bank the first byte is
      unsigned long bank = from & (~(priv->bank_fill[0]-1));
      unsigned long offset = from & (priv->bank_fill[0]-1);
      unsigned long get = len;
      if (priv->bank_fill[0] - offset < len)
	 get = priv->bank_fill[0] - offset;

      bank /= priv->bank_fill[0];
      map_copy_from(map,buf + *retlen,bank*my_bank_size + offset,get);

      len -= get;
      *retlen += get;
      from += get;
   }
   return 0;
}

/* Pass the flags value that the flash return before it re-entered read
   mode. */
static void jedec_flash_failed(unsigned char code)
{
   /* Bit 5 being high indicates that there was an internal device
      failure, erasure time limits exceeded or something */
   if ((code & (1 << 5)) != 0)
   {
      printk("mtd: Internal Flash failure\n");
      return;
   }
   printk("mtd: Programming didn't take\n");
}

/* This uses the erasure function described in the AMD Flash Handbook,
   it will work for flashes with a fixed sector size only. Flashes with
   a selection of sector sizes (ie the AMD Am29F800B) will need a different
   routine. This routine tries to parallize erasing multiple chips/sectors
   where possible */
static int flash_erase(struct mtd_info *mtd, struct erase_info *instr)
{
   // Does IO to the currently selected chip
   #define flread(x) map_read8(map,chip->base+((x)<<chip->addrshift))
   #define flwrite(v,x) map_write8(map,v,chip->base+((x)<<chip->addrshift))

   unsigned long Time = 0;
   unsigned long NoTime = 0;
   unsigned long start = instr->addr, len = instr->len;
   unsigned int I;
   struct map_info *map = mtd->priv;
   struct jedec_private *priv = map->fldrv_priv;

   // Verify the arguments..
   if (start + len > mtd->size ||
       (start % mtd->erasesize) != 0 ||
       (len % mtd->erasesize) != 0 ||
       (len/mtd->erasesize) == 0)
      return -EINVAL;

   jedec_flash_chip_scan(priv,start,len);

   // Start the erase sequence on each chip
   for (I = 0; priv->chips[I].jedec != 0 && I < MAX_JEDEC_CHIPS; I++)
   {
      unsigned long off;
      struct jedec_flash_chip *chip = priv->chips + I;

      if (chip->length == 0)
	 continue;

      if (chip->start + chip->length > chip->size)
      {
	 printk("DIE\n");
	 return -EIO;
      }

      flwrite(0xF0,chip->start + 0x555);
      flwrite(0xAA,chip->start + 0x555);
      flwrite(0x55,chip->start + 0x2AA);
      flwrite(0x80,chip->start + 0x555);
      flwrite(0xAA,chip->start + 0x555);
      flwrite(0x55,chip->start + 0x2AA);

      /* Once we start selecting the erase sectors the delay between each
         command must not exceed 50us or it will immediately start erasing
         and ignore the other sectors */
      for (off = 0; off < len; off += chip->sectorsize)
      {
	 // Check to make sure we didn't timeout
	 flwrite(0x30,chip->start + off);
	 if (off == 0)
	    continue;
	 if ((flread(chip->start + off) & (1 << 3)) != 0)
	 {
	    printk("mtd: Ack! We timed out the erase timer!\n");
	    return -EIO;
	 }
      }
   }

   /* We could split this into a timer routine and return early, performing
      background erasure.. Maybe later if the need warrents */

   /* Poll the flash for erasure completion, specs say this can take as long
      as 480 seconds to do all the sectors (for a 2 meg flash).
      Erasure time is dependent on chip age, temp and wear.. */

   /* This being a generic routine assumes a 32 bit bus. It does read32s
      and bundles interleved chips into the same grouping. This will work
      for all bus widths */
   Time = 0;
   NoTime = 0;
   for (I = 0; priv->chips[I].jedec != 0 && I < MAX_JEDEC_CHIPS; I++)
   {
      struct jedec_flash_chip *chip = priv->chips + I;
      unsigned long off = 0;
      unsigned todo[4] = {0,0,0,0};
      unsigned todo_left = 0;
      unsigned J;

      if (chip->length == 0)
	 continue;

      /* Find all chips in this data line, realistically this is all
         or nothing up to the interleve count */
      for (J = 0; priv->chips[J].jedec != 0 && J < MAX_JEDEC_CHIPS; J++)
      {
	 if ((priv->chips[J].base & (~((1<<chip->addrshift)-1))) ==
	     (chip->base & (~((1<<chip->addrshift)-1))))
	 {
	    todo_left++;
	    todo[priv->chips[J].base & ((1<<chip->addrshift)-1)] = 1;
	 }
      }

      /*      printk("todo: %x %x %x %x\n",(short)todo[0],(short)todo[1],
	      (short)todo[2],(short)todo[3]);
      */
      while (1)
      {
	 __u32 Last[4];
	 unsigned long Count = 0;

	 /* During erase bit 7 is held low and bit 6 toggles, we watch this,
	    should it stop toggling or go high then the erase is completed,
  	    or this is not really flash ;> */
	 switch (map->buswidth) {
	 case 1:
	    Last[0] = map_read8(map,(chip->base >> chip->addrshift) + chip->start + off);
	    Last[1] = map_read8(map,(chip->base >> chip->addrshift) + chip->start + off);
	    Last[2] = map_read8(map,(chip->base >> chip->addrshift) + chip->start + off);
	    break;
	 case 2:
	    Last[0] = map_read16(map,(chip->base >> chip->addrshift) + chip->start + off);
	    Last[1] = map_read16(map,(chip->base >> chip->addrshift) + chip->start + off);
	    Last[2] = map_read16(map,(chip->base >> chip->addrshift) + chip->start + off);
	    break;
	 case 3:
	    Last[0] = map_read32(map,(chip->base >> chip->addrshift) + chip->start + off);
	    Last[1] = map_read32(map,(chip->base >> chip->addrshift) + chip->start + off);
	    Last[2] = map_read32(map,(chip->base >> chip->addrshift) + chip->start + off);
	    break;
	 }
	 Count = 3;
	 while (todo_left != 0)
	 {
	    for (J = 0; J != 4; J++)
	    {
	       __u8 Byte1 = (Last[(Count-1)%4] >> (J*8)) & 0xFF;
	       __u8 Byte2 = (Last[(Count-2)%4] >> (J*8)) & 0xFF;
	       __u8 Byte3 = (Last[(Count-3)%4] >> (J*8)) & 0xFF;
	       if (todo[J] == 0)
		  continue;

	       if ((Byte1 & (1 << 7)) == 0 && Byte1 != Byte2)
	       {
//		  printk("Check %x %x %x\n",(short)J,(short)Byte1,(short)Byte2);
		  continue;
	       }

	       if (Byte1 == Byte2)
	       {
		  jedec_flash_failed(Byte3);
		  return -EIO;
	       }

	       todo[J] = 0;
	       todo_left--;
	    }

/*	    if (NoTime == 0)
	       Time += HZ/10 - schedule_timeout(HZ/10);*/
	    NoTime = 0;

	    switch (map->buswidth) {
	    case 1:
	       Last[Count % 4] = map_read8(map,(chip->base >> chip->addrshift) + chip->start + off);
	      break;
	    case 2:
	       Last[Count % 4] = map_read16(map,(chip->base >> chip->addrshift) + chip->start + off);
	      break;
	    case 4:
	       Last[Count % 4] = map_read32(map,(chip->base >> chip->addrshift) + chip->start + off);
	      break;
	    }
	    Count++;

/*	    // Count time, max of 15s per sector (according to AMD)
	    if (Time > 15*len/mtd->erasesize*HZ)
	    {
	       printk("mtd: Flash Erase Timed out\n");
	       return -EIO;
	    }	    */
	 }

	 // Skip to the next chip if we used chip erase
	 if (chip->length == chip->size)
	    off = chip->size;
	 else
	    off += chip->sectorsize;

	 if (off >= chip->length)
	    break;
	 NoTime = 1;
      }

      for (J = 0; priv->chips[J].jedec != 0 && J < MAX_JEDEC_CHIPS; J++)
      {
	 if ((priv->chips[J].base & (~((1<<chip->addrshift)-1))) ==
	     (chip->base & (~((1<<chip->addrshift)-1))))
	    priv->chips[J].length = 0;
      }
   }

   //printk("done\n");
   instr->state = MTD_ERASE_DONE;
   mtd_erase_callback(instr);
   return 0;

   #undef flread
   #undef flwrite
}

/* This is the simple flash writing function. It writes to every byte, in
   sequence. It takes care of how to properly address the flash if
   the flash is interleved. It can only be used if all the chips in the
   array are identical!*/
static int flash_write(struct mtd_info *mtd, loff_t start, size_t len,
		       size_t *retlen, const u_char *buf)
{
   /* Does IO to the currently selected chip. It takes the bank addressing
      base (which is divisible by the chip size) adds the necessary lower bits
      of addrshift (interleave index) and then adds the control register index. */
   #define flread(x) map_read8(map,base+(off&((1<<chip->addrshift)-1))+((x)<<chip->addrshift))
   #define flwrite(v,x) map_write8(map,v,base+(off&((1<<chip->addrshift)-1))+((x)<<chip->addrshift))

   struct map_info *map = mtd->priv;
   struct jedec_private *priv = map->fldrv_priv;
   unsigned long base;
   unsigned long off;
   size_t save_len = len;

   if (start + len > mtd->size)
      return -EIO;

   //printk("Here");

   //printk("flash_write: start is %x, len is %x\n",start,(unsigned long)len);
   while (len != 0)
   {
      struct jedec_flash_chip *chip = priv->chips;
      unsigned long bank;
      unsigned long boffset;

      // Compute the base of the flash.
      off = ((unsigned long)start) % (chip->size << chip->addrshift);
      base = start - off;

      // Perform banked addressing translation.
      bank = base & (~(priv->bank_fill[0]-1));
      boffset = base & (priv->bank_fill[0]-1);
      bank = (bank/priv->bank_fill[0])*my_bank_size;
      base = bank + boffset;

    //  printk("Flasing %X %X %X\n",base,chip->size,len);
     // printk("off is %x, compare with %x\n",off,chip->size << chip->addrshift);

      // Loop over this page
      for (; off != (chip->size << chip->addrshift) && len != 0; start++, len--, off++,buf++)
      {
	 unsigned char oldbyte = map_read8(map,base+off);
	 unsigned char Last[4];
	 unsigned long Count = 0;

	 if (oldbyte == *buf) {
	//	 printk("oldbyte and *buf is %x,len is %x\n",oldbyte,len);
	    continue;
	 }
	 if (((~oldbyte) & *buf) != 0)
	    printk("mtd: warn: Trying to set a 0 to a 1\n");

	 // Write
	 flwrite(0xAA,0x555);
	 flwrite(0x55,0x2AA);
	 flwrite(0xA0,0x555);
	 map_write8(map,*buf,base + off);
	 Last[0] = map_read8(map,base + off);
	 Last[1] = map_read8(map,base + off);
	 Last[2] = map_read8(map,base + off);

	 /* Wait for the flash to finish the operation. We store the last 4
	    status bytes that have been retrieved so we can determine why
	    it failed. The toggle bits keep toggling when there is a
	    failure */
	 for (Count = 3; Last[(Count - 1) % 4] != Last[(Count - 2) % 4] &&
	      Count < 10000; Count++)
	    Last[Count % 4] = map_read8(map,base + off);
	 if (Last[(Count - 1) % 4] != *buf)
	 {
	    jedec_flash_failed(Last[(Count - 3) % 4]);
	    return -EIO;
	 }
      }
   }
   *retlen = save_len;
   return 0;
}

/* This is used to enhance the speed of the erase routine,
   when things are being done to multiple chips it is possible to
   parallize the operations, particularly full memory erases of multi
   chip memories benifit */
static void jedec_flash_chip_scan(struct jedec_private *priv,unsigned long start,
		     unsigned long len)
{
   unsigned int I;

   // Zero the records
   for (I = 0; priv->chips[I].jedec != 0 && I < MAX_JEDEC_CHIPS; I++)
      priv->chips[I].start = priv->chips[I].length = 0;

   // Intersect the region with each chip
   for (I = 0; priv->chips[I].jedec != 0 && I < MAX_JEDEC_CHIPS; I++)
   {
      struct jedec_flash_chip *chip = priv->chips + I;
      unsigned long ByteStart;
      unsigned long ChipEndByte = chip->offset + (chip->size << chip->addrshift);

      // End is before this chip or the start is after it
      if (start+len < chip->offset ||
	  ChipEndByte - (1 << chip->addrshift) < start)
	 continue;

      if (start < chip->offset)
      {
	 ByteStart = chip->offset;
	 chip->start = 0;
      }
      else
      {
	 chip->start = (start - chip->offset + (1 << chip->addrshift)-1) >> chip->addrshift;
	 ByteStart = start;
      }

      if (start + len >= ChipEndByte)
	 chip->length = (ChipEndByte - ByteStart) >> chip->addrshift;
      else
	 chip->length = (start + len - ByteStart + (1 << chip->addrshift)-1) >> chip->addrshift;
   }
}

int __init jedec_init(void)
{
	register_mtd_chip_driver(&jedec_chipdrv);
	return 0;
}

static void __exit jedec_exit(void)
{
	unregister_mtd_chip_driver(&jedec_chipdrv);
}

module_init(jedec_init);
module_exit(jedec_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Jason Gunthorpe <[e-mail]> et al.");
MODULE_DESCRIPTION("Old MTD chip driver for JEDEC-compliant flash chips");