bpp.c

底层驱动开发

          pins |= BPP_PP_nStrobe;
          set_pins(pins, minor);
      }

      return cnt - remaining;
}

/*
 * Write data using ECP mode. Watch out that the port may be set up
 * for reading. If so, turn the port around.
 */
static long write_ecp(unsigned minor, const char __user *c, unsigned long cnt)
{
      unsigned short pins = get_pins(minor);
      unsigned long remaining = cnt;

      if (instances[minor].direction) {
          int rc;

            /* Event 47 Request bus be turned around */
          pins |= BPP_PP_nInit;
          set_pins(pins, minor);

            /* Wait for Event 49: Peripheral relinquished bus */
          rc = wait_for(BPP_GP_PError, 0, TIME_PResponse, minor);

          pins |= BPP_PP_nAutoFd;
          instances[minor].direction = 0;
          set_pins(pins, minor);
      }

      while (remaining > 0) {
          unsigned char byte;
          int rc;

          if (get_user(byte, c))
		  return -EFAULT;

          rc = wait_for(0, BPP_GP_Busy, TIME_PResponse, minor);
          if (rc == -1) return -ETIMEDOUT;

          c += 1;

          bpp_outb_p(byte, base_addrs[minor]);

          pins &= ~BPP_PP_nStrobe;
          set_pins(pins, minor);

          pins |= BPP_PP_nStrobe;
          rc = wait_for(BPP_GP_Busy, 0, TIME_PResponse, minor);
          if (rc == -1) return -EIO;

          set_pins(pins, minor);
      }

      return cnt - remaining;
}

/*
 * Write to the peripheral. Be sensitive of the current mode. If I'm
 * in a mode that can be turned around (ECP) then just do
 * that. Otherwise, terminate and do my writing in compat mode. This
 * is the safest course as any device can handle it.
 */
static ssize_t bpp_write(struct file *f, const char __user *c, size_t cnt, loff_t * ppos)
{
      long errno = 0;
      unsigned minor = iminor(f->f_dentry->d_inode);
      if (minor >= BPP_NO) return -ENODEV;
      if (!instances[minor].present) return -ENODEV;

      switch (instances[minor].mode) {

        case ECP:
        case ECP_RLE:
          errno = write_ecp(minor, c, cnt);
          break;
        case COMPATIBILITY:
          errno = write_compat(minor, c, cnt);
          break;
        default:
          terminate(minor);
          errno = write_compat(minor, c, cnt);
      }

      return errno;
}

static int bpp_ioctl(struct inode *inode, struct file *f, unsigned int cmd,
		 unsigned long arg)
{
      int errno = 0;

      unsigned minor = iminor(inode);
      if (minor >= BPP_NO) return -ENODEV;
      if (!instances[minor].present) return -ENODEV;


      switch (cmd) {

        case BPP_PUT_PINS:
          set_pins(arg, minor);
          break;

        case BPP_GET_PINS:
          errno = get_pins(minor);
          break;

        case BPP_PUT_DATA:
          bpp_outb_p(arg, base_addrs[minor]);
          break;

        case BPP_GET_DATA:
          errno = bpp_inb_p(base_addrs[minor]);
          break;

        case BPP_SET_INPUT:
          if (arg)
            if (instances[minor].enhanced) {
                unsigned short bits = get_pins(minor);
                instances[minor].direction = 0x20;
                set_pins(bits, minor);
            } else {
                errno = -ENOTTY;
            }
          else {
              unsigned short bits = get_pins(minor);
              instances[minor].direction = 0x00;
              set_pins(bits, minor);
          }
          break;

        default:
            errno = -EINVAL;
      }

      return errno;
}

static struct file_operations bpp_fops = {
	.owner =	THIS_MODULE,
	.read =		bpp_read,
	.write =	bpp_write,
	.ioctl =	bpp_ioctl,
	.open =		bpp_open,
	.release =	bpp_release,
};

#if defined(__i386__)

#define collectLptPorts()  {}

static void probeLptPort(unsigned idx)
{
      unsigned int testvalue;
      const unsigned short lpAddr = base_addrs[idx];

      instances[idx].present = 0;
      instances[idx].enhanced = 0;
      instances[idx].direction = 0;
      instances[idx].mode = COMPATIBILITY;
      instances[idx].run_length = 0;
      instances[idx].run_flag = 0;
      if (!request_region(lpAddr,3, dev_name)) return;

      /*
       * First, make sure the instance exists. Do this by writing to
       * the data latch and reading the value back. If the port *is*
       * present, test to see if it supports extended-mode
       * operation. This will be required for IEEE1284 reverse
       * transfers.
       */

      outb_p(BPP_PROBE_CODE, lpAddr);
      for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
            ;
      testvalue = inb_p(lpAddr);
      if (testvalue == BPP_PROBE_CODE) {
            unsigned save;
            instances[idx].present = 1;

            save = inb_p(lpAddr+2);
            for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
                  ;
            outb_p(save|0x20, lpAddr+2);
            for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
                  ;
            outb_p(~BPP_PROBE_CODE, lpAddr);
            for (testvalue=0; testvalue<BPP_DELAY; testvalue++)
                  ;
            testvalue = inb_p(lpAddr);
            if ((testvalue&0xff) == (0xff&~BPP_PROBE_CODE))
                  instances[idx].enhanced = 0;
            else
                  instances[idx].enhanced = 1;
            outb_p(save, lpAddr+2);
      }
      else {
            release_region(lpAddr,3);
      }
      /*
       * Leave the port in compat idle mode.
       */
      set_pins(BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, idx);

      printk("bpp%d: Port at 0x%03x: Enhanced mode %s\n", idx, base_addrs[idx],
            instances[idx].enhanced? "SUPPORTED" : "UNAVAILABLE");
}

static inline void freeLptPort(int idx)
{
      release_region(base_addrs[idx], 3);
}

#endif

#if defined(__sparc__)

static void __iomem *map_bpp(struct sbus_dev *dev, int idx)
{
      return sbus_ioremap(&dev->resource[0], 0, BPP_SIZE, "bpp");
}

static int collectLptPorts(void)
{
	struct sbus_bus *bus;
	struct sbus_dev *dev;
	int count;

	count = 0;
	for_all_sbusdev(dev, bus) {
		if (strcmp(dev->prom_name, "SUNW,bpp") == 0) {
			if (count >= BPP_NO) {
				printk(KERN_NOTICE
				       "bpp: More than %d bpp ports,"
				       " rest is ignored\n", BPP_NO);
				return count;
			}
			base_addrs[count] = map_bpp(dev, count);
			count++;
		}
	}
	return count;
}

static void probeLptPort(unsigned idx)
{
      void __iomem *rp = base_addrs[idx];
      __u32 csr;
      char *brand;

      instances[idx].present = 0;
      instances[idx].enhanced = 0;
      instances[idx].direction = 0;
      instances[idx].mode = COMPATIBILITY;
      instances[idx].run_length = 0;
      instances[idx].run_flag = 0;

      if (!rp) return;

      instances[idx].present = 1;
      instances[idx].enhanced = 1;   /* Sure */

      csr = sbus_readl(rp + BPP_CSR);
      if ((csr & P_DRAINING) != 0 && (csr & P_ERR_PEND) == 0) {
            udelay(20);
            csr = sbus_readl(rp + BPP_CSR);
            if ((csr & P_DRAINING) != 0 && (csr & P_ERR_PEND) == 0) {
                  printk("bpp%d: DRAINING still active (0x%08x)\n", idx, csr);
            }
      }
      printk("bpp%d: reset with 0x%08x ..", idx, csr);
      sbus_writel((csr | P_RESET) & ~P_INT_EN, rp + BPP_CSR);
      udelay(500);
      sbus_writel(sbus_readl(rp + BPP_CSR) & ~P_RESET, rp + BPP_CSR);
      csr = sbus_readl(rp + BPP_CSR);
      printk(" done with csr=0x%08x ocr=0x%04x\n",
         csr, sbus_readw(rp + BPP_OCR));

      switch (csr & P_DEV_ID_MASK) {
      case P_DEV_ID_ZEBRA:
            brand = "Zebra";
            break;
      case P_DEV_ID_L64854:
            brand = "DMA2";
            break;
      default:
            brand = "Unknown";
      }
      printk("bpp%d: %s at %p\n", idx, brand, rp);

      /*
       * Leave the port in compat idle mode.
       */
      set_pins(BPP_PP_nAutoFd|BPP_PP_nStrobe|BPP_PP_nInit, idx);

      return;
}

static inline void freeLptPort(int idx)
{
      sbus_iounmap(base_addrs[idx], BPP_SIZE);
}

#endif

static int __init bpp_init(void)
{
	int rc;
	unsigned idx;

	rc = collectLptPorts();
	if (rc == 0)
		return -ENODEV;

	rc = register_chrdev(BPP_MAJOR, dev_name, &bpp_fops);
	if (rc < 0)
		return rc;

	for (idx = 0; idx < BPP_NO; idx++) {
		instances[idx].opened = 0;
		probeLptPort(idx);
	}
	devfs_mk_dir("bpp");
	for (idx = 0; idx < BPP_NO; idx++) {
		devfs_mk_cdev(MKDEV(BPP_MAJOR, idx),
				S_IFCHR | S_IRUSR | S_IWUSR, "bpp/%d", idx);
	}

	return 0;
}

static void __exit bpp_cleanup(void)
{
	unsigned idx;

	for (idx = 0; idx < BPP_NO; idx++)
		devfs_remove("bpp/%d", idx);
	devfs_remove("bpp");
	unregister_chrdev(BPP_MAJOR, dev_name);

	for (idx = 0;  idx < BPP_NO; idx++) {
		if (instances[idx].present)
			freeLptPort(idx);
	}
}

module_init(bpp_init);
module_exit(bpp_cleanup);

MODULE_LICENSE("GPL");