/*
   * ccio-rm-dma.c:
   *	DMA management routines for first generation cache-coherent machines.
   *	"Real Mode" operation refers to U2/Uturn chip operation. The chip
   *      can perform coherency checks w/o using the I/O MMU. That's all we
   *      need until support for more than 4GB phys mem is needed.
   * 
   *	This is the trivial case - basically what x86 does.
   *
   *	Drawbacks of using Real Mode are:
   *	o outbound DMA is slower since one isn't using the prefetching
   *	  U2 can do for outbound DMA.
   *	o Ability to do scatter/gather in HW is also lost.
   *      o only known to work with PCX-W processor. (eg C360)
   *        (PCX-U/U+ are not coherent with U2 in real mode.)
   *
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   *
   * Original version/author:
   *      CVSROOT=:pserver:anonymous@198.186.203.37:/cvsroot/linux-parisc
   *      cvs -z3 co linux/arch/parisc/kernel/dma-rm.c
   *
   *	(C) Copyright 2000 Philipp Rumpf <prumpf@tux.org>
   *
   *
   * Adopted for The Puffin Group's parisc-linux port by Grant Grundler.
   *	(C) Copyright 2000 Grant Grundler <grundler@puffin.external.hp.com>
   *	
   */
  
  #include <linux/types.h>
  #include <linux/init.h>
  #include <linux/mm.h>
  #include <linux/string.h>
  #include <linux/pci.h>

  #include <linux/gfp.h>

  
  #include <asm/uaccess.h>
  
  #include <asm/io.h>
  #include <asm/hardware.h>
  #include <asm/page.h>
  
  /* Only chose "ccio" since that's what HP-UX calls it....
  ** Make it easier for folks to migrate from one to the other :^)
  */
  #define MODULE_NAME "ccio"
  
  #define U2_IOA_RUNWAY 0x580
  #define U2_BC_GSC     0x501
  #define UTURN_IOA_RUNWAY 0x581
  #define UTURN_BC_GSC     0x502
  
  #define IS_U2(id) ( \
      (((id)->hw_type == HPHW_IOA) && ((id)->hversion == U2_IOA_RUNWAY)) || \
      (((id)->hw_type == HPHW_BCPORT) && ((id)->hversion == U2_BC_GSC))  \
  )
  
  #define IS_UTURN(id) ( \
      (((id)->hw_type == HPHW_IOA) && ((id)->hversion == UTURN_IOA_RUNWAY)) || \
      (((id)->hw_type == HPHW_BCPORT) && ((id)->hversion == UTURN_BC_GSC))  \
  )
  
  static int ccio_dma_supported( struct pci_dev *dev, u64 mask)
  {
  	if (dev == NULL) {
  		printk(KERN_ERR MODULE_NAME ": EISA/ISA/et al not supported
  ");
  		BUG();
  		return(0);
  	}
  
  	/* only support 32-bit devices (ie PCI/GSC) */
  	return((int) (mask >= 0xffffffffUL));
  }
  
  
  static void *ccio_alloc_consistent(struct pci_dev *dev, size_t size,
  				 dma_addr_t *handle)
  {
  	void *ret;
  	
  	ret = (void *)__get_free_pages(GFP_ATOMIC, get_order(size));
  
  	if (ret != NULL) {
  		memset(ret, 0, size);
  		*handle = virt_to_phys(ret);
  	}
  	return ret;
  }
  	
  static void ccio_free_consistent(struct pci_dev *dev, size_t size,
  			       void *vaddr, dma_addr_t handle)
  {
  	free_pages((unsigned long)vaddr, get_order(size));
  }
  
  static dma_addr_t ccio_map_single(struct pci_dev *dev, void *ptr, size_t size,
  			  int direction)
  {
  	return virt_to_phys(ptr);
  }
  
  static void ccio_unmap_single(struct pci_dev *dev, dma_addr_t dma_addr,
  			    size_t size, int direction)
  {
  	/* Nothing to do */
  }
  
  
  static int ccio_map_sg(struct pci_dev *dev, struct scatterlist *sglist, int nents, int direction)
  {
  	int tmp = nents;
  
          /* KISS: map each buffer separately. */
  	while (nents) {
  		sg_dma_address(sglist) = ccio_map_single(dev, sglist->address, sglist->length, direction);
  		sg_dma_len(sglist) = sglist->length;
  		nents--;
  		sglist++;
  	}
  
  	return tmp;
  }
  
  
  static void ccio_unmap_sg(struct pci_dev *dev, struct scatterlist *sglist, int nents, int direction)
  {
  #if 0
  	while (nents) {
  		ccio_unmap_single(dev, sg_dma_address(sglist), sg_dma_len(sglist), direction);
  		nents--;
  		sglist++;
  	}
  	return;
  #else
  	/* Do nothing (copied from current ccio_unmap_single()  :^) */
  #endif
  }
  
  
  static struct pci_dma_ops ccio_ops = {
  	ccio_dma_supported,
  	ccio_alloc_consistent,
  	ccio_free_consistent,
  	ccio_map_single,
  	ccio_unmap_single,
  	ccio_map_sg,
  	ccio_unmap_sg,
  	NULL,                   /* dma_sync_single_for_cpu : NOP for U2 */
  	NULL,                   /* dma_sync_single_for_device : NOP for U2 */
  	NULL,                   /* dma_sync_sg_for_cpu     : ditto */
  	NULL,                   /* dma_sync_sg_for_device     : ditto */
  };
  
  
  /*
  ** Determine if u2 should claim this chip (return 0) or not (return 1).
  ** If so, initialize the chip and tell other partners in crime they
  ** have work to do.
  */
  static int
  ccio_probe(struct parisc_device *dev)
  {
  	printk(KERN_INFO "%s found %s at 0x%lx
  ", MODULE_NAME,
  			dev->id.hversion == U2_BC_GSC ? "U2" : "UTurn",

  			dev->hpa.start);

  
  /*
  ** FIXME - should check U2 registers to verify it's really running
  ** in "Real Mode".
  */
  
  #if 0
  /* will need this for "Virtual Mode" operation */
  	ccio_hw_init(ccio_dev);
  	ccio_common_init(ccio_dev);
  #endif
  	hppa_dma_ops = &ccio_ops;
  	return 0;
  }
  
  static struct parisc_device_id ccio_tbl[] = {
  	{ HPHW_BCPORT, HVERSION_REV_ANY_ID, U2_BC_GSC, 0xc },
  	{ HPHW_BCPORT, HVERSION_REV_ANY_ID, UTURN_BC_GSC, 0xc },
  	{ 0, }
  };
  
  static struct parisc_driver ccio_driver = {
  	.name =		"U2/Uturn",
  	.id_table =	ccio_tbl,
  	.probe =	ccio_probe,
  };
  
  void __init ccio_init(void)
  {
  	register_parisc_driver(&ccio_driver);
  }