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nwflash.c

/*
 * Flash memory interface rev.5 driver for the Intel
 * Flash chips used on the NetWinder.
 *
 * 20/08/2000     RMK   use __ioremap to map flash into virtual memory
 *                make a few more places use "volatile"
 * 22/05/2001     RMK   - Lock read against write
 *                - merge printk level changes (with mods) from Alan Cox.
 *                - use *ppos as the file position, not file->f_pos.
 *                - fix check for out of range pos and r/w size
 *
 * Please note that we are tampering with the only flash chip in the
 * machine, which contains the bootup code.  We therefore have the
 * power to convert these machines into doorstops...
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/miscdevice.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/init.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>

#include <asm/hardware/dec21285.h>
#include <asm/io.h>
#include <asm/leds.h>
#include <asm/mach-types.h>
#include <asm/system.h>
#include <asm/uaccess.h>

/*****************************************************************************/
#include <asm/nwflash.h>

#define     NWFLASH_VERSION "6.4"

static void kick_open(void);
static int get_flash_id(void);
static int erase_block(int nBlock);
static int write_block(unsigned long p, const char __user *buf, int count);

#define KFLASH_SIZE     1024*1024   //1 Meg
#define KFLASH_SIZE4    4*1024*1024 //4 Meg
#define KFLASH_ID 0x89A6            //Intel flash
#define KFLASH_ID4      0xB0D4            //Intel flash 4Meg

static int flashdebug;        //if set - we will display progress msgs

static int gbWriteEnable;
static int gbWriteBase64Enable;
static volatile unsigned char *FLASH_BASE;
static int gbFlashSize = KFLASH_SIZE;
static DEFINE_MUTEX(nwflash_mutex);

extern spinlock_t gpio_lock;

static int get_flash_id(void)
{
      volatile unsigned int c1, c2;

      /*
       * try to get flash chip ID
       */
      kick_open();
      c2 = inb(0x80);
      *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x90;
      udelay(15);
      c1 = *(volatile unsigned char *) FLASH_BASE;
      c2 = inb(0x80);

      /*
       * on 4 Meg flash the second byte is actually at offset 2...
       */
      if (c1 == 0xB0)
            c2 = *(volatile unsigned char *) (FLASH_BASE + 2);
      else
            c2 = *(volatile unsigned char *) (FLASH_BASE + 1);

      c2 += (c1 << 8);

      /*
       * set it back to read mode
       */
      *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;

      if (c2 == KFLASH_ID4)
            gbFlashSize = KFLASH_SIZE4;

      return c2;
}

static int flash_ioctl(struct inode *inodep, struct file *filep, unsigned int cmd, unsigned long arg)
{
      switch (cmd) {
      case CMD_WRITE_DISABLE:
            gbWriteBase64Enable = 0;
            gbWriteEnable = 0;
            break;

      case CMD_WRITE_ENABLE:
            gbWriteEnable = 1;
            break;

      case CMD_WRITE_BASE64K_ENABLE:
            gbWriteBase64Enable = 1;
            break;

      default:
            gbWriteBase64Enable = 0;
            gbWriteEnable = 0;
            return -EINVAL;
      }
      return 0;
}

static ssize_t flash_read(struct file *file, char __user *buf, size_t size,
                    loff_t *ppos)
{
      unsigned long p = *ppos;
      unsigned int count = size;
      int ret = 0;

      if (flashdebug)
            printk(KERN_DEBUG "flash_read: flash_read: offset=0x%lX, "
                   "buffer=%p, count=0x%X.\n", p, buf, count);

      if (count)
            ret = -ENXIO;

      if (p < gbFlashSize) {
            if (count > gbFlashSize - p)
                  count = gbFlashSize - p;

            /*
             * We now lock against reads and writes. --rmk
             */
            if (mutex_lock_interruptible(&nwflash_mutex))
                  return -ERESTARTSYS;

            ret = copy_to_user(buf, (void *)(FLASH_BASE + p), count);
            if (ret == 0) {
                  ret = count;
                  *ppos += count;
            } else
                  ret = -EFAULT;
            mutex_unlock(&nwflash_mutex);
      }
      return ret;
}

static ssize_t flash_write(struct file *file, const char __user *buf,
                     size_t size, loff_t * ppos)
{
      unsigned long p = *ppos;
      unsigned int count = size;
      int written;
      int nBlock, temp, rc;
      int i, j;

      if (flashdebug)
            printk("flash_write: offset=0x%lX, buffer=0x%p, count=0x%X.\n",
                   p, buf, count);

      if (!gbWriteEnable)
            return -EINVAL;

      if (p < 64 * 1024 && (!gbWriteBase64Enable))
            return -EINVAL;

      /*
       * check for out of range pos or count
       */
      if (p >= gbFlashSize)
            return count ? -ENXIO : 0;

      if (count > gbFlashSize - p)
            count = gbFlashSize - p;
                  
      if (!access_ok(VERIFY_READ, buf, count))
            return -EFAULT;

      /*
       * We now lock against reads and writes. --rmk
       */
      if (mutex_lock_interruptible(&nwflash_mutex))
            return -ERESTARTSYS;

      written = 0;

      leds_event(led_claim);
      leds_event(led_green_on);

      nBlock = (int) p >> 16; //block # of 64K bytes

      /*
       * # of 64K blocks to erase and write
       */
      temp = ((int) (p + count) >> 16) - nBlock + 1;

      /*
       * write ends at exactly 64k boundary?
       */
      if (((int) (p + count) & 0xFFFF) == 0)
            temp -= 1;

      if (flashdebug)
            printk(KERN_DEBUG "flash_write: writing %d block(s) "
                  "starting at %d.\n", temp, nBlock);

      for (; temp; temp--, nBlock++) {
            if (flashdebug)
                  printk(KERN_DEBUG "flash_write: erasing block %d.\n", nBlock);

            /*
             * first we have to erase the block(s), where we will write...
             */
            i = 0;
            j = 0;
        RetryBlock:
            do {
                  rc = erase_block(nBlock);
                  i++;
            } while (rc && i < 10);

            if (rc) {
                  printk(KERN_ERR "flash_write: erase error %x\n", rc);
                  break;
            }
            if (flashdebug)
                  printk(KERN_DEBUG "flash_write: writing offset %lX, "
                         "from buf %p, bytes left %X.\n", p, buf,
                         count - written);

            /*
             * write_block will limit write to space left in this block
             */
            rc = write_block(p, buf, count - written);
            j++;

            /*
             * if somehow write verify failed? Can't happen??
             */
            if (!rc) {
                  /*
                   * retry up to 10 times
                   */
                  if (j < 10)
                        goto RetryBlock;
                  else
                        /*
                         * else quit with error...
                         */
                        rc = -1;

            }
            if (rc < 0) {
                  printk(KERN_ERR "flash_write: write error %X\n", rc);
                  break;
            }
            p += rc;
            buf += rc;
            written += rc;
            *ppos += rc;

            if (flashdebug)
                  printk(KERN_DEBUG "flash_write: written 0x%X bytes OK.\n", written);
      }

      /*
       * restore reg on exit
       */
      leds_event(led_release);

      mutex_unlock(&nwflash_mutex);

      return written;
}


/*
 * The memory devices use the full 32/64 bits of the offset, and so we cannot
 * check against negative addresses: they are ok. The return value is weird,
 * though, in that case (0).
 *
 * also note that seeking relative to the "end of file" isn't supported:
 * it has no meaning, so it returns -EINVAL.
 */
static loff_t flash_llseek(struct file *file, loff_t offset, int orig)
{
      loff_t ret;

      lock_kernel();
      if (flashdebug)
            printk(KERN_DEBUG "flash_llseek: offset=0x%X, orig=0x%X.\n",
                   (unsigned int) offset, orig);

      switch (orig) {
      case 0:
            if (offset < 0) {
                  ret = -EINVAL;
                  break;
            }

            if ((unsigned int) offset > gbFlashSize) {
                  ret = -EINVAL;
                  break;
            }

            file->f_pos = (unsigned int) offset;
            ret = file->f_pos;
            break;
      case 1:
            if ((file->f_pos + offset) > gbFlashSize) {
                  ret = -EINVAL;
                  break;
            }
            if ((file->f_pos + offset) < 0) {
                  ret = -EINVAL;
                  break;
            }
            file->f_pos += offset;
            ret = file->f_pos;
            break;
      default:
            ret = -EINVAL;
      }
      unlock_kernel();
      return ret;
}


/*
 * assume that main Write routine did the parameter checking...
 * so just go ahead and erase, what requested!
 */

static int erase_block(int nBlock)
{
      volatile unsigned int c1;
      volatile unsigned char *pWritePtr;
      unsigned long timeout;
      int temp, temp1;

      /*
       * orange LED == erase
       */
      leds_event(led_amber_on);

      /*
       * reset footbridge to the correct offset 0 (...0..3)
       */
      *CSR_ROMWRITEREG = 0;

      /*
       * dummy ROM read
       */
      c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);

      kick_open();
      /*
       * reset status if old errors
       */
      *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;

      /*
       * erase a block...
       * aim at the middle of a current block...
       */
      pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + 0x8000 + (nBlock << 16)));
      /*
       * dummy read
       */
      c1 = *pWritePtr;

      kick_open();
      /*
       * erase
       */
      *(volatile unsigned char *) pWritePtr = 0x20;

      /*
       * confirm
       */
      *(volatile unsigned char *) pWritePtr = 0xD0;

      /*
       * wait 10 ms
       */
      msleep(10);

      /*
       * wait while erasing in process (up to 10 sec)
       */
      timeout = jiffies + 10 * HZ;
      c1 = 0;
      while (!(c1 & 0x80) && time_before(jiffies, timeout)) {
            msleep(10);
            /*
             * read any address
             */
            c1 = *(volatile unsigned char *) (pWritePtr);
            //              printk("Flash_erase: status=%X.\n",c1);
      }

      /*
       * set flash for normal read access
       */
      kick_open();
//      *(volatile unsigned char*)(FLASH_BASE+0x8000) = 0xFF;
      *(volatile unsigned char *) pWritePtr = 0xFF;   //back to normal operation

      /*
       * check if erase errors were reported
       */
      if (c1 & 0x20) {
            printk(KERN_ERR "flash_erase: err at %p\n", pWritePtr);

            /*
             * reset error
             */
            *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;
            return -2;
      }

      /*
       * just to make sure - verify if erased OK...
       */
      msleep(10);

      pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + (nBlock << 16)));

      for (temp = 0; temp < 16 * 1024; temp++, pWritePtr += 4) {
            if ((temp1 = *(volatile unsigned int *) pWritePtr) != 0xFFFFFFFF) {
                  printk(KERN_ERR "flash_erase: verify err at %p = %X\n",
                         pWritePtr, temp1);
                  return -1;
            }
      }

      return 0;

}

/*
 * write_block will limit number of bytes written to the space in this block
 */
static int write_block(unsigned long p, const char __user *buf, int count)
{
      volatile unsigned int c1;
      volatile unsigned int c2;
      unsigned char *pWritePtr;
      unsigned int uAddress;
      unsigned int offset;
      unsigned long timeout;
      unsigned long timeout1;

      /*
       * red LED == write
       */
      leds_event(led_amber_off);
      leds_event(led_red_on);

      pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));

      /*
       * check if write will end in this block....
       */
      offset = p & 0xFFFF;

      if (offset + count > 0x10000)
            count = 0x10000 - offset;

      /*
       * wait up to 30 sec for this block
       */
      timeout = jiffies + 30 * HZ;

      for (offset = 0; offset < count; offset++, pWritePtr++) {
            uAddress = (unsigned int) pWritePtr;
            uAddress &= 0xFFFFFFFC;
            if (__get_user(c2, buf + offset))
                  return -EFAULT;

        WriteRetry:
            /*
             * dummy read
             */
            c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);

            /*
             * kick open the write gate
             */
            kick_open();

            /*
             * program footbridge to the correct offset...0..3
             */
            *CSR_ROMWRITEREG = (unsigned int) pWritePtr & 3;

            /*
             * write cmd
             */
            *(volatile unsigned char *) (uAddress) = 0x40;

            /*
             * data to write
             */
            *(volatile unsigned char *) (uAddress) = c2;

            /*
             * get status
             */
            *(volatile unsigned char *) (FLASH_BASE + 0x10000) = 0x70;

            c1 = 0;

            /*
             * wait up to 1 sec for this byte
             */
            timeout1 = jiffies + 1 * HZ;

            /*
             * while not ready...
             */
            while (!(c1 & 0x80) && time_before(jiffies, timeout1))
                  c1 = *(volatile unsigned char *) (FLASH_BASE + 0x8000);

            /*
             * if timeout getting status
             */
            if (time_after_eq(jiffies, timeout1)) {
                  kick_open();
                  /*
                   * reset err
                   */
                  *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;

                  goto WriteRetry;
            }
            /*
             * switch on read access, as a default flash operation mode
             */
            kick_open();
            /*
             * read access
             */
            *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0xFF;

            /*
             * if hardware reports an error writing, and not timeout - 
             * reset the chip and retry
             */
            if (c1 & 0x10) {
                  kick_open();
                  /*
                   * reset err
                   */
                  *(volatile unsigned char *) (FLASH_BASE + 0x8000) = 0x50;

                  /*
                   * before timeout?
                   */
                  if (time_before(jiffies, timeout)) {
                        if (flashdebug)
                              printk(KERN_DEBUG "write_block: Retrying write at 0x%X)n",
                                     pWritePtr - FLASH_BASE);

                        /*
                         * no LED == waiting
                         */
                        leds_event(led_amber_off);
                        /*
                         * wait couple ms
                         */
                        msleep(10);
                        /*
                         * red LED == write
                         */
                        leds_event(led_red_on);

                        goto WriteRetry;
                  } else {
                        printk(KERN_ERR "write_block: timeout at 0x%X\n",
                               pWritePtr - FLASH_BASE);
                        /*
                         * return error -2
                         */
                        return -2;

                  }
            }
      }

      /*
       * green LED == read/verify
       */
      leds_event(led_amber_off);
      leds_event(led_green_on);

      msleep(10);

      pWritePtr = (unsigned char *) ((unsigned int) (FLASH_BASE + p));

      for (offset = 0; offset < count; offset++) {
            char c, c1;
            if (__get_user(c, buf))
                  return -EFAULT;
            buf++;
            if ((c1 = *pWritePtr++) != c) {
                  printk(KERN_ERR "write_block: verify error at 0x%X (%02X!=%02X)\n",
                         pWritePtr - FLASH_BASE, c1, c);
                  return 0;
            }
      }

      return count;
}


static void kick_open(void)
{
      unsigned long flags;

      /*
       * we want to write a bit pattern XXX1 to Xilinx to enable
       * the write gate, which will be open for about the next 2ms.
       */
      spin_lock_irqsave(&gpio_lock, flags);
      cpld_modify(1, 1);
      spin_unlock_irqrestore(&gpio_lock, flags);

      /*
       * let the ISA bus to catch on...
       */
      udelay(25);
}

static const struct file_operations flash_fops =
{
      .owner            = THIS_MODULE,
      .llseek           = flash_llseek,
      .read       = flash_read,
      .write            = flash_write,
      .ioctl            = flash_ioctl,
};

static struct miscdevice flash_miscdev =
{
      FLASH_MINOR,
      "nwflash",
      &flash_fops
};

static int __init nwflash_init(void)
{
      int ret = -ENODEV;

      if (machine_is_netwinder()) {
            int id;

            FLASH_BASE = ioremap(DC21285_FLASH, KFLASH_SIZE4);
            if (!FLASH_BASE)
                  goto out;

            id = get_flash_id();
            if ((id != KFLASH_ID) && (id != KFLASH_ID4)) {
                  ret = -ENXIO;
                  iounmap((void *)FLASH_BASE);
                  printk("Flash: incorrect ID 0x%04X.\n", id);
                  goto out;
            }

            printk("Flash ROM driver v.%s, flash device ID 0x%04X, size %d Mb.\n",
                   NWFLASH_VERSION, id, gbFlashSize / (1024 * 1024));

            ret = misc_register(&flash_miscdev);
            if (ret < 0) {
                  iounmap((void *)FLASH_BASE);
            }
      }
out:
      return ret;
}

static void __exit nwflash_exit(void)
{
      misc_deregister(&flash_miscdev);
      iounmap((void *)FLASH_BASE);
}

MODULE_LICENSE("GPL");

module_param(flashdebug, bool, 0644);

module_init(nwflash_init);
module_exit(nwflash_exit);

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