text: /*
  ** ccio-dma.c:
  **	DMA management routines for first generation cache-coherent machines.
  **	Program U2/Uturn in "Virtual Mode" and use the I/O MMU.
  **
  **	(c) Copyright 2000 Grant Grundler
  **	(c) Copyright 2000 Ryan Bradetich
  **	(c) Copyright 2000 Hewlett-Packard Company
  **
  ** 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.
  **
  **
  **  "Real Mode" operation refers to U2/Uturn chip operation.
  **  U2/Uturn were designed to perform coherency checks w/o using
  **  the I/O MMU - basically what x86 does.
  **
  **  Philipp Rumpf has a "Real Mode" driver for PCX-W machines at:
  **      CVSROOT=:pserver:anonymous@198.186.203.37:/cvsroot/linux-parisc
  **      cvs -z3 co linux/arch/parisc/kernel/dma-rm.c
  **
  **  I've rewritten his code to work under TPG's tree. See ccio-rm-dma.c.
  **
  **  Drawbacks of using Real Mode are:
  **	o outbound DMA is slower - U2 won't prefetch data (GSC+ XQL signal).
  **      o Inbound DMA less efficient - U2 can't use DMA_FAST attribute.
  **	o Ability to do scatter/gather in HW is lost.
  **	o Doesn't work under PCX-U/U+ machines since they didn't follow
  **        the coherency design originally worked out. Only PCX-W does.
  */
  
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/mm.h>
  #include <linux/spinlock.h>
  #include <linux/slab.h>
  #include <linux/string.h>
  #include <linux/pci.h>
  #include <linux/reboot.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/scatterlist.h>
  #include <linux/iommu-helper.h>
  #include <linux/export.h>
  
  #include <asm/byteorder.h>
  #include <asm/cache.h>		/* for L1_CACHE_BYTES */
  #include <linux/uaccess.h>
  #include <asm/page.h>
  #include <asm/dma.h>
  #include <asm/io.h>
  #include <asm/hardware.h>       /* for register_module() */
  #include <asm/parisc-device.h>
  
  /* 
  ** Choose "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"
  
  #undef DEBUG_CCIO_RES
  #undef DEBUG_CCIO_RUN
  #undef DEBUG_CCIO_INIT
  #undef DEBUG_CCIO_RUN_SG
  
  #ifdef CONFIG_PROC_FS
  /* depends on proc fs support. But costs CPU performance. */
  #undef CCIO_COLLECT_STATS
  #endif
  
  #include <asm/runway.h>		/* for proc_runway_root */
  
  #ifdef DEBUG_CCIO_INIT
  #define DBG_INIT(x...)  printk(x)
  #else
  #define DBG_INIT(x...)
  #endif
  
  #ifdef DEBUG_CCIO_RUN
  #define DBG_RUN(x...)   printk(x)
  #else
  #define DBG_RUN(x...)
  #endif
  
  #ifdef DEBUG_CCIO_RES
  #define DBG_RES(x...)   printk(x)
  #else
  #define DBG_RES(x...)
  #endif
  
  #ifdef DEBUG_CCIO_RUN_SG
  #define DBG_RUN_SG(x...) printk(x)
  #else
  #define DBG_RUN_SG(x...)
  #endif
  
  #define CCIO_INLINE	inline
  #define WRITE_U32(value, addr) __raw_writel(value, addr)
  #define READ_U32(addr) __raw_readl(addr)
  
  #define U2_IOA_RUNWAY 0x580
  #define U2_BC_GSC     0x501
  #define UTURN_IOA_RUNWAY 0x581
  #define UTURN_BC_GSC     0x502
  
  #define IOA_NORMAL_MODE      0x00020080 /* IO_CONTROL to turn on CCIO        */
  #define CMD_TLB_DIRECT_WRITE 35         /* IO_COMMAND for I/O TLB Writes     */
  #define CMD_TLB_PURGE        33         /* IO_COMMAND to Purge I/O TLB entry */
  
  #define CCIO_MAPPING_ERROR    (~(dma_addr_t)0)
  
  struct ioa_registers {
          /* Runway Supervisory Set */
          int32_t    unused1[12];
          uint32_t   io_command;             /* Offset 12 */
          uint32_t   io_status;              /* Offset 13 */
          uint32_t   io_control;             /* Offset 14 */
          int32_t    unused2[1];
  
          /* Runway Auxiliary Register Set */
          uint32_t   io_err_resp;            /* Offset  0 */
          uint32_t   io_err_info;            /* Offset  1 */
          uint32_t   io_err_req;             /* Offset  2 */
          uint32_t   io_err_resp_hi;         /* Offset  3 */
          uint32_t   io_tlb_entry_m;         /* Offset  4 */
          uint32_t   io_tlb_entry_l;         /* Offset  5 */
          uint32_t   unused3[1];
          uint32_t   io_pdir_base;           /* Offset  7 */
          uint32_t   io_io_low_hv;           /* Offset  8 */
          uint32_t   io_io_high_hv;          /* Offset  9 */
          uint32_t   unused4[1];
          uint32_t   io_chain_id_mask;       /* Offset 11 */
          uint32_t   unused5[2];
          uint32_t   io_io_low;              /* Offset 14 */
          uint32_t   io_io_high;             /* Offset 15 */
  };
  
  /*
  ** IOA Registers
  ** -------------
  **
  ** Runway IO_CONTROL Register (+0x38)
  ** 
  ** The Runway IO_CONTROL register controls the forwarding of transactions.
  **
  ** | 0  ...  13  |  14 15 | 16 ... 21 | 22 | 23 24 |  25 ... 31 |
  ** |    HV       |   TLB  |  reserved | HV | mode  |  reserved  |
  **
  ** o mode field indicates the address translation of transactions
  **   forwarded from Runway to GSC+:
  **       Mode Name     Value        Definition
  **       Off (default)   0          Opaque to matching addresses.
  **       Include         1          Transparent for matching addresses.
  **       Peek            3          Map matching addresses.
  **
  **       + "Off" mode: Runway transactions which match the I/O range
  **         specified by the IO_IO_LOW/IO_IO_HIGH registers will be ignored.
  **       + "Include" mode: all addresses within the I/O range specified
  **         by the IO_IO_LOW and IO_IO_HIGH registers are transparently
  **         forwarded. This is the I/O Adapter's normal operating mode.
  **       + "Peek" mode: used during system configuration to initialize the
  **         GSC+ bus. Runway Write_Shorts in the address range specified by
  **         IO_IO_LOW and IO_IO_HIGH are forwarded through the I/O Adapter
  **         *AND* the GSC+ address is remapped to the Broadcast Physical
  **         Address space by setting the 14 high order address bits of the
  **         32 bit GSC+ address to ones.
  **
  ** o TLB field affects transactions which are forwarded from GSC+ to Runway.
  **   "Real" mode is the poweron default.
  ** 
  **   TLB Mode  Value  Description
  **   Real        0    No TLB translation. Address is directly mapped and the
  **                    virtual address is composed of selected physical bits.
  **   Error       1    Software fills the TLB manually.
  **   Normal      2    IOA fetches IO TLB misses from IO PDIR (in host memory).
  **
  **
  ** IO_IO_LOW_HV	  +0x60 (HV dependent)
  ** IO_IO_HIGH_HV  +0x64 (HV dependent)
  ** IO_IO_LOW      +0x78	(Architected register)
  ** IO_IO_HIGH     +0x7c	(Architected register)
  **
  ** IO_IO_LOW and IO_IO_HIGH set the lower and upper bounds of the
  ** I/O Adapter address space, respectively.
  **
  ** 0  ... 7 | 8 ... 15 |  16   ...   31 |
  ** 11111111 | 11111111 |      address   |
  **
  ** Each LOW/HIGH pair describes a disjoint address space region.
  ** (2 per GSC+ port). Each incoming Runway transaction address is compared
  ** with both sets of LOW/HIGH registers. If the address is in the range
  ** greater than or equal to IO_IO_LOW and less than IO_IO_HIGH the transaction
  ** for forwarded to the respective GSC+ bus.
  ** Specify IO_IO_LOW equal to or greater than IO_IO_HIGH to avoid specifying
  ** an address space region.
  **
  ** In order for a Runway address to reside within GSC+ extended address space:
  **	Runway Address [0:7]    must identically compare to 8'b11111111
  **	Runway Address [8:11]   must be equal to IO_IO_LOW(_HV)[16:19]
  ** 	Runway Address [12:23]  must be greater than or equal to
  **	           IO_IO_LOW(_HV)[20:31] and less than IO_IO_HIGH(_HV)[20:31].
  **	Runway Address [24:39]  is not used in the comparison.
  **
  ** When the Runway transaction is forwarded to GSC+, the GSC+ address is
  ** as follows:
  **	GSC+ Address[0:3]	4'b1111
  **	GSC+ Address[4:29]	Runway Address[12:37]
  **	GSC+ Address[30:31]	2'b00
  **
  ** All 4 Low/High registers must be initialized (by PDC) once the lower bus
  ** is interrogated and address space is defined. The operating system will
  ** modify the architectural IO_IO_LOW and IO_IO_HIGH registers following
  ** the PDC initialization.  However, the hardware version dependent IO_IO_LOW
  ** and IO_IO_HIGH registers should not be subsequently altered by the OS.
  ** 
  ** Writes to both sets of registers will take effect immediately, bypassing
  ** the queues, which ensures that subsequent Runway transactions are checked
  ** against the updated bounds values. However reads are queued, introducing
  ** the possibility of a read being bypassed by a subsequent write to the same
  ** register. This sequence can be avoided by having software wait for read
  ** returns before issuing subsequent writes.
  */
  
  struct ioc {
  	struct ioa_registers __iomem *ioc_regs;  /* I/O MMU base address */
  	u8  *res_map;	                /* resource map, bit == pdir entry */
  	u64 *pdir_base;	                /* physical base address */
  	u32 pdir_size; 			/* bytes, function of IOV Space size */
  	u32 res_hint;	                /* next available IOVP - 
  					   circular search */
  	u32 res_size;		    	/* size of resource map in bytes */
  	spinlock_t res_lock;
  
  #ifdef CCIO_COLLECT_STATS
  #define CCIO_SEARCH_SAMPLE 0x100
  	unsigned long avg_search[CCIO_SEARCH_SAMPLE];
  	unsigned long avg_idx;		  /* current index into avg_search */
  	unsigned long used_pages;
  	unsigned long msingle_calls;
  	unsigned long msingle_pages;
  	unsigned long msg_calls;
  	unsigned long msg_pages;
  	unsigned long usingle_calls;
  	unsigned long usingle_pages;
  	unsigned long usg_calls;
  	unsigned long usg_pages;
  #endif
  	unsigned short cujo20_bug;
  
  	/* STUFF We don't need in performance path */
  	u32 chainid_shift; 		/* specify bit location of chain_id */
  	struct ioc *next;		/* Linked list of discovered iocs */
  	const char *name;		/* device name from firmware */
  	unsigned int hw_path;           /* the hardware path this ioc is associatd with */
  	struct pci_dev *fake_pci_dev;   /* the fake pci_dev for non-pci devs */
  	struct resource mmio_region[2]; /* The "routed" MMIO regions */
  };
  
  static struct ioc *ioc_list;
  static int ioc_count;
  
  /**************************************************************
  *
  *   I/O Pdir Resource Management
  *
  *   Bits set in the resource map are in use.
  *   Each bit can represent a number of pages.
  *   LSbs represent lower addresses (IOVA's).
  *
  *   This was was copied from sba_iommu.c. Don't try to unify
  *   the two resource managers unless a way to have different
  *   allocation policies is also adjusted. We'd like to avoid
  *   I/O TLB thrashing by having resource allocation policy
  *   match the I/O TLB replacement policy.
  *
  ***************************************************************/
  #define IOVP_SIZE PAGE_SIZE
  #define IOVP_SHIFT PAGE_SHIFT
  #define IOVP_MASK PAGE_MASK
  
  /* Convert from IOVP to IOVA and vice versa. */
  #define CCIO_IOVA(iovp,offset) ((iovp) | (offset))
  #define CCIO_IOVP(iova) ((iova) & IOVP_MASK)
  
  #define PDIR_INDEX(iovp)    ((iovp)>>IOVP_SHIFT)
  #define MKIOVP(pdir_idx)    ((long)(pdir_idx) << IOVP_SHIFT)
  #define MKIOVA(iovp,offset) (dma_addr_t)((long)iovp | (long)offset)
  
  /*
  ** Don't worry about the 150% average search length on a miss.
  ** If the search wraps around, and passes the res_hint, it will
  ** cause the kernel to panic anyhow.
  */
  #define CCIO_SEARCH_LOOP(ioc, res_idx, mask, size)  \
         for(; res_ptr < res_end; ++res_ptr) { \
  		int ret;\
  		unsigned int idx;\
  		idx = (unsigned int)((unsigned long)res_ptr - (unsigned long)ioc->res_map); \
  		ret = iommu_is_span_boundary(idx << 3, pages_needed, 0, boundary_size);\
  		if ((0 == (*res_ptr & mask)) && !ret) { \
  			*res_ptr |= mask; \
  			res_idx = idx;\
  			ioc->res_hint = res_idx + (size >> 3); \
  			goto resource_found; \
  		} \
  	}
  
  #define CCIO_FIND_FREE_MAPPING(ioa, res_idx, mask, size) \
         u##size *res_ptr = (u##size *)&((ioc)->res_map[ioa->res_hint & ~((size >> 3) - 1)]); \
         u##size *res_end = (u##size *)&(ioc)->res_map[ioa->res_size]; \
         CCIO_SEARCH_LOOP(ioc, res_idx, mask, size); \
         res_ptr = (u##size *)&(ioc)->res_map[0]; \
         CCIO_SEARCH_LOOP(ioa, res_idx, mask, size);
  
  /*
  ** Find available bit in this ioa's resource map.
  ** Use a "circular" search:
  **   o Most IOVA's are "temporary" - avg search time should be small.
  ** o keep a history of what happened for debugging
  ** o KISS.
  **
  ** Perf optimizations:
  ** o search for log2(size) bits at a time.
  ** o search for available resource bits using byte/word/whatever.
  ** o use different search for "large" (eg > 4 pages) or "very large"
  **   (eg > 16 pages) mappings.
  */
  
  /**
   * ccio_alloc_range - Allocate pages in the ioc's resource map.
   * @ioc: The I/O Controller.
   * @pages_needed: The requested number of pages to be mapped into the
   * I/O Pdir...
   *
   * This function searches the resource map of the ioc to locate a range
   * of available pages for the requested size.
   */
  static int
  ccio_alloc_range(struct ioc *ioc, struct device *dev, size_t size)
  {
  	unsigned int pages_needed = size >> IOVP_SHIFT;
  	unsigned int res_idx;
  	unsigned long boundary_size;
  #ifdef CCIO_COLLECT_STATS
  	unsigned long cr_start = mfctl(16);
  #endif
  	
  	BUG_ON(pages_needed == 0);
  	BUG_ON((pages_needed * IOVP_SIZE) > DMA_CHUNK_SIZE);
       
  	DBG_RES("%s() size: %d pages_needed %d\n", 
  		__func__, size, pages_needed);
  
  	/*
  	** "seek and ye shall find"...praying never hurts either...
  	** ggg sacrifices another 710 to the computer gods.
  	*/
  
  	boundary_size = ALIGN((unsigned long long)dma_get_seg_boundary(dev) + 1,
  			      1ULL << IOVP_SHIFT) >> IOVP_SHIFT;
  
  	if (pages_needed <= 8) {
  		/*
  		 * LAN traffic will not thrash the TLB IFF the same NIC
  		 * uses 8 adjacent pages to map separate payload data.
  		 * ie the same byte in the resource bit map.
  		 */
  #if 0
  		/* FIXME: bit search should shift it's way through
  		 * an unsigned long - not byte at a time. As it is now,
  		 * we effectively allocate this byte to this mapping.
  		 */
  		unsigned long mask = ~(~0UL >> pages_needed);
  		CCIO_FIND_FREE_MAPPING(ioc, res_idx, mask, 8);
  #else
  		CCIO_FIND_FREE_MAPPING(ioc, res_idx, 0xff, 8);
  #endif
  	} else if (pages_needed <= 16) {
  		CCIO_FIND_FREE_MAPPING(ioc, res_idx, 0xffff, 16);
  	} else if (pages_needed <= 32) {
  		CCIO_FIND_FREE_MAPPING(ioc, res_idx, ~(unsigned int)0, 32);
  #ifdef __LP64__
  	} else if (pages_needed <= 64) {
  		CCIO_FIND_FREE_MAPPING(ioc, res_idx, ~0UL, 64);
  #endif
  	} else {
  		panic("%s: %s() Too many pages to map. pages_needed: %u\n",
  		       __FILE__,  __func__, pages_needed);
  	}
  
  	panic("%s: %s() I/O MMU is out of mapping resources.\n", __FILE__,
  	      __func__);
  	
  resource_found:
  	
  	DBG_RES("%s() res_idx %d res_hint: %d\n",
  		__func__, res_idx, ioc->res_hint);
  
  #ifdef CCIO_COLLECT_STATS
  	{
  		unsigned long cr_end = mfctl(16);
  		unsigned long tmp = cr_end - cr_start;
  		/* check for roll over */
  		cr_start = (cr_end < cr_start) ?  -(tmp) : (tmp);
  	}
  	ioc->avg_search[ioc->avg_idx++] = cr_start;
  	ioc->avg_idx &= CCIO_SEARCH_SAMPLE - 1;
  	ioc->used_pages += pages_needed;
  #endif
  	/* 
  	** return the bit address.
  	*/
  	return res_idx << 3;
  }
  
  #define CCIO_FREE_MAPPINGS(ioc, res_idx, mask, size) \
          u##size *res_ptr = (u##size *)&((ioc)->res_map[res_idx]); \
          BUG_ON((*res_ptr & mask) != mask); \
          *res_ptr &= ~(mask);
  
  /**
   * ccio_free_range - Free pages from the ioc's resource map.
   * @ioc: The I/O Controller.
   * @iova: The I/O Virtual Address.
   * @pages_mapped: The requested number of pages to be freed from the
   * I/O Pdir.
   *
   * This function frees the resouces allocated for the iova.
   */
  static void
  ccio_free_range(struct ioc *ioc, dma_addr_t iova, unsigned long pages_mapped)
  {
  	unsigned long iovp = CCIO_IOVP(iova);
  	unsigned int res_idx = PDIR_INDEX(iovp) >> 3;
  
  	BUG_ON(pages_mapped == 0);
  	BUG_ON((pages_mapped * IOVP_SIZE) > DMA_CHUNK_SIZE);
  	BUG_ON(pages_mapped > BITS_PER_LONG);
  
  	DBG_RES("%s():  res_idx: %d pages_mapped %d\n", 
  		__func__, res_idx, pages_mapped);
  
  #ifdef CCIO_COLLECT_STATS
  	ioc->used_pages -= pages_mapped;
  #endif
  
  	if(pages_mapped <= 8) {
  #if 0
  		/* see matching comments in alloc_range */
  		unsigned long mask = ~(~0UL >> pages_mapped);
  		CCIO_FREE_MAPPINGS(ioc, res_idx, mask, 8);
  #else
  		CCIO_FREE_MAPPINGS(ioc, res_idx, 0xffUL, 8);
  #endif
  	} else if(pages_mapped <= 16) {
  		CCIO_FREE_MAPPINGS(ioc, res_idx, 0xffffUL, 16);
  	} else if(pages_mapped <= 32) {
  		CCIO_FREE_MAPPINGS(ioc, res_idx, ~(unsigned int)0, 32);
  #ifdef __LP64__
  	} else if(pages_mapped <= 64) {
  		CCIO_FREE_MAPPINGS(ioc, res_idx, ~0UL, 64);
  #endif
  	} else {
  		panic("%s:%s() Too many pages to unmap.\n", __FILE__,
  		      __func__);
  	}
  }
  
  /****************************************************************
  **
  **          CCIO dma_ops support routines
  **
  *****************************************************************/
  
  typedef unsigned long space_t;
  #define KERNEL_SPACE 0
  
  /*
  ** DMA "Page Type" and Hints 
  ** o if SAFE_DMA isn't set, mapping is for FAST_DMA. SAFE_DMA should be
  **   set for subcacheline DMA transfers since we don't want to damage the
  **   other part of a cacheline.
  ** o SAFE_DMA must be set for "memory" allocated via pci_alloc_consistent().
  **   This bit tells U2 to do R/M/W for partial cachelines. "Streaming"
  **   data can avoid this if the mapping covers full cache lines.
  ** o STOP_MOST is needed for atomicity across cachelines.
  **   Apparently only "some EISA devices" need this.
  **   Using CONFIG_ISA is hack. Only the IOA with EISA under it needs
  **   to use this hint iff the EISA devices needs this feature.
  **   According to the U2 ERS, STOP_MOST enabled pages hurt performance.
  ** o PREFETCH should *not* be set for cases like Multiple PCI devices
  **   behind GSCtoPCI (dino) bus converter. Only one cacheline per GSC
  **   device can be fetched and multiply DMA streams will thrash the
  **   prefetch buffer and burn memory bandwidth. See 6.7.3 "Prefetch Rules
  **   and Invalidation of Prefetch Entries".
  **
  ** FIXME: the default hints need to be per GSC device - not global.
  ** 
  ** HP-UX dorks: linux device driver programming model is totally different
  **    than HP-UX's. HP-UX always sets HINT_PREFETCH since it's drivers
  **    do special things to work on non-coherent platforms...linux has to
  **    be much more careful with this.
  */
  #define IOPDIR_VALID    0x01UL
  #define HINT_SAFE_DMA   0x02UL	/* used for pci_alloc_consistent() pages */
  #ifdef CONFIG_EISA
  #define HINT_STOP_MOST  0x04UL	/* LSL support */
  #else
  #define HINT_STOP_MOST  0x00UL	/* only needed for "some EISA devices" */
  #endif
  #define HINT_UDPATE_ENB 0x08UL  /* not used/supported by U2 */
  #define HINT_PREFETCH   0x10UL	/* for outbound pages which are not SAFE */
  
  
  /*
  ** Use direction (ie PCI_DMA_TODEVICE) to pick hint.
  ** ccio_alloc_consistent() depends on this to get SAFE_DMA
  ** when it passes in BIDIRECTIONAL flag.
  */
  static u32 hint_lookup[] = {
  	[PCI_DMA_BIDIRECTIONAL]	= HINT_STOP_MOST | HINT_SAFE_DMA | IOPDIR_VALID,
  	[PCI_DMA_TODEVICE]	= HINT_STOP_MOST | HINT_PREFETCH | IOPDIR_VALID,
  	[PCI_DMA_FROMDEVICE]	= HINT_STOP_MOST | IOPDIR_VALID,
  };
  
  /**
   * ccio_io_pdir_entry - Initialize an I/O Pdir.
   * @pdir_ptr: A pointer into I/O Pdir.
   * @sid: The Space Identifier.
   * @vba: The virtual address.
   * @hints: The DMA Hint.
   *
   * Given a virtual address (vba, arg2) and space id, (sid, arg1),
   * load the I/O PDIR entry pointed to by pdir_ptr (arg0). Each IO Pdir
   * entry consists of 8 bytes as shown below (MSB == bit 0):
   *
   *
   * WORD 0:
   * +------+----------------+-----------------------------------------------+
   * | Phys | Virtual Index  |               Phys                            |
   * | 0:3  |     0:11       |               4:19                            |
   * |4 bits|   12 bits      |              16 bits                          |
   * +------+----------------+-----------------------------------------------+
   * WORD 1:
   * +-----------------------+-----------------------------------------------+
   * |      Phys    |  Rsvd  | Prefetch |Update |Rsvd  |Lock  |Safe  |Valid  |
   * |     20:39    |        | Enable   |Enable |      |Enable|DMA   |       |
   * |    20 bits   | 5 bits | 1 bit    |1 bit  |2 bits|1 bit |1 bit |1 bit  |
   * +-----------------------+-----------------------------------------------+
   *
   * The virtual index field is filled with the results of the LCI
   * (Load Coherence Index) instruction.  The 8 bits used for the virtual
   * index are bits 12:19 of the value returned by LCI.
   */ 
  static void CCIO_INLINE
  ccio_io_pdir_entry(u64 *pdir_ptr, space_t sid, unsigned long vba,
  		   unsigned long hints)
  {
  	register unsigned long pa;
  	register unsigned long ci; /* coherent index */
  
  	/* We currently only support kernel addresses */
  	BUG_ON(sid != KERNEL_SPACE);
  
  	/*
  	** WORD 1 - low order word
  	** "hints" parm includes the VALID bit!
  	** "dep" clobbers the physical address offset bits as well.
  	*/
  	pa = virt_to_phys(vba);
  	asm volatile("depw  %1,31,12,%0" : "+r" (pa) : "r" (hints));
  	((u32 *)pdir_ptr)[1] = (u32) pa;
  
  	/*
  	** WORD 0 - high order word
  	*/
  
  #ifdef __LP64__
  	/*
  	** get bits 12:15 of physical address
  	** shift bits 16:31 of physical address
  	** and deposit them
  	*/
  	asm volatile ("extrd,u %1,15,4,%0" : "=r" (ci) : "r" (pa));
  	asm volatile ("extrd,u %1,31,16,%0" : "+r" (pa) : "r" (pa));
  	asm volatile ("depd  %1,35,4,%0" : "+r" (pa) : "r" (ci));
  #else
  	pa = 0;
  #endif
  	/*
  	** get CPU coherency index bits
  	** Grab virtual index [0:11]
  	** Deposit virt_idx bits into I/O PDIR word
  	*/
  	asm volatile ("lci %%r0(%1), %0" : "=r" (ci) : "r" (vba));
  	asm volatile ("extru %1,19,12,%0" : "+r" (ci) : "r" (ci));
  	asm volatile ("depw  %1,15,12,%0" : "+r" (pa) : "r" (ci));
  
  	((u32 *)pdir_ptr)[0] = (u32) pa;
  
  
  	/* FIXME: PCX_W platforms don't need FDC/SYNC. (eg C360)
  	**        PCX-U/U+ do. (eg C200/C240)
  	**        PCX-T'? Don't know. (eg C110 or similar K-class)
  	**
  	** See PDC_MODEL/option 0/SW_CAP word for "Non-coherent IO-PDIR bit".
  	** Hopefully we can patch (NOP) these out at boot time somehow.
  	**
  	** "Since PCX-U employs an offset hash that is incompatible with
  	** the real mode coherence index generation of U2, the PDIR entry
  	** must be flushed to memory to retain coherence."
  	*/
  	asm volatile("fdc %%r0(%0)" : : "r" (pdir_ptr));
  	asm volatile("sync");
  }
  
  /**
   * ccio_clear_io_tlb - Remove stale entries from the I/O TLB.
   * @ioc: The I/O Controller.
   * @iovp: The I/O Virtual Page.
   * @byte_cnt: The requested number of bytes to be freed from the I/O Pdir.
   *
   * Purge invalid I/O PDIR entries from the I/O TLB.
   *
   * FIXME: Can we change the byte_cnt to pages_mapped?
   */
  static CCIO_INLINE void
  ccio_clear_io_tlb(struct ioc *ioc, dma_addr_t iovp, size_t byte_cnt)
  {
  	u32 chain_size = 1 << ioc->chainid_shift;
  
  	iovp &= IOVP_MASK;	/* clear offset bits, just want pagenum */
  	byte_cnt += chain_size;
  
  	while(byte_cnt > chain_size) {
  		WRITE_U32(CMD_TLB_PURGE | iovp, &ioc->ioc_regs->io_command);
  		iovp += chain_size;
  		byte_cnt -= chain_size;
  	}
  }
  
  /**
   * ccio_mark_invalid - Mark the I/O Pdir entries invalid.
   * @ioc: The I/O Controller.
   * @iova: The I/O Virtual Address.
   * @byte_cnt: The requested number of bytes to be freed from the I/O Pdir.
   *
   * Mark the I/O Pdir entries invalid and blow away the corresponding I/O
   * TLB entries.
   *
   * FIXME: at some threshold it might be "cheaper" to just blow
   *        away the entire I/O TLB instead of individual entries.
   *
   * FIXME: Uturn has 256 TLB entries. We don't need to purge every
   *        PDIR entry - just once for each possible TLB entry.
   *        (We do need to maker I/O PDIR entries invalid regardless).
   *
   * FIXME: Can we change byte_cnt to pages_mapped?
   */ 
  static CCIO_INLINE void
  ccio_mark_invalid(struct ioc *ioc, dma_addr_t iova, size_t byte_cnt)
  {
  	u32 iovp = (u32)CCIO_IOVP(iova);
  	size_t saved_byte_cnt;
  
  	/* round up to nearest page size */
  	saved_byte_cnt = byte_cnt = ALIGN(byte_cnt, IOVP_SIZE);
  
  	while(byte_cnt > 0) {
  		/* invalidate one page at a time */
  		unsigned int idx = PDIR_INDEX(iovp);
  		char *pdir_ptr = (char *) &(ioc->pdir_base[idx]);
  
  		BUG_ON(idx >= (ioc->pdir_size / sizeof(u64)));
  		pdir_ptr[7] = 0;	/* clear only VALID bit */ 
  		/*
  		** FIXME: PCX_W platforms don't need FDC/SYNC. (eg C360)
  		**   PCX-U/U+ do. (eg C200/C240)
  		** See PDC_MODEL/option 0/SW_CAP for "Non-coherent IO-PDIR bit".
  		**
  		** Hopefully someone figures out how to patch (NOP) the
  		** FDC/SYNC out at boot time.
  		*/
  		asm volatile("fdc %%r0(%0)" : : "r" (pdir_ptr[7]));
  
  		iovp     += IOVP_SIZE;
  		byte_cnt -= IOVP_SIZE;
  	}
  
  	asm volatile("sync");
  	ccio_clear_io_tlb(ioc, CCIO_IOVP(iova), saved_byte_cnt);
  }
  
  /****************************************************************
  **
  **          CCIO dma_ops
  **
  *****************************************************************/
  
  /**
   * ccio_dma_supported - Verify the IOMMU supports the DMA address range.
   * @dev: The PCI device.
   * @mask: A bit mask describing the DMA address range of the device.
   */
  static int 
  ccio_dma_supported(struct device *dev, u64 mask)
  {
  	if(dev == NULL) {
  		printk(KERN_ERR MODULE_NAME ": EISA/ISA/et al not supported\n");
  		BUG();
  		return 0;
  	}
  
  	/* only support 32-bit devices (ie PCI/GSC) */
  	return (int)(mask == 0xffffffffUL);
  }
  
  /**
   * ccio_map_single - Map an address range into the IOMMU.
   * @dev: The PCI device.
   * @addr: The start address of the DMA region.
   * @size: The length of the DMA region.
   * @direction: The direction of the DMA transaction (to/from device).
   *
   * This function implements the pci_map_single function.
   */
  static dma_addr_t 
  ccio_map_single(struct device *dev, void *addr, size_t size,
  		enum dma_data_direction direction)
  {
  	int idx;
  	struct ioc *ioc;
  	unsigned long flags;
  	dma_addr_t iovp;
  	dma_addr_t offset;
  	u64 *pdir_start;
  	unsigned long hint = hint_lookup[(int)direction];
  
  	BUG_ON(!dev);
  	ioc = GET_IOC(dev);
  	if (!ioc)
  		return CCIO_MAPPING_ERROR;
  
  	BUG_ON(size <= 0);
  
  	/* save offset bits */
  	offset = ((unsigned long) addr) & ~IOVP_MASK;
  
  	/* round up to nearest IOVP_SIZE */
  	size = ALIGN(size + offset, IOVP_SIZE);
  	spin_lock_irqsave(&ioc->res_lock, flags);
  
  #ifdef CCIO_COLLECT_STATS
  	ioc->msingle_calls++;
  	ioc->msingle_pages += size >> IOVP_SHIFT;
  #endif
  
  	idx = ccio_alloc_range(ioc, dev, size);
  	iovp = (dma_addr_t)MKIOVP(idx);
  
  	pdir_start = &(ioc->pdir_base[idx]);
  
  	DBG_RUN("%s() 0x%p -> 0x%lx size: %0x%x\n",
  		__func__, addr, (long)iovp | offset, size);
  
  	/* If not cacheline aligned, force SAFE_DMA on the whole mess */
  	if((size % L1_CACHE_BYTES) || ((unsigned long)addr % L1_CACHE_BYTES))
  		hint |= HINT_SAFE_DMA;
  
  	while(size > 0) {
  		ccio_io_pdir_entry(pdir_start, KERNEL_SPACE, (unsigned long)addr, hint);
  
  		DBG_RUN(" pdir %p %08x%08x\n",
  			pdir_start,
  			(u32) (((u32 *) pdir_start)[0]),
  			(u32) (((u32 *) pdir_start)[1]));
  		++pdir_start;
  		addr += IOVP_SIZE;
  		size -= IOVP_SIZE;
  	}
  
  	spin_unlock_irqrestore(&ioc->res_lock, flags);
  
  	/* form complete address */
  	return CCIO_IOVA(iovp, offset);
  }
  
  
  static dma_addr_t
  ccio_map_page(struct device *dev, struct page *page, unsigned long offset,
  		size_t size, enum dma_data_direction direction,
  		unsigned long attrs)
  {
  	return ccio_map_single(dev, page_address(page) + offset, size,
  			direction);
  }
  
  
  /**
   * ccio_unmap_page - Unmap an address range from the IOMMU.
   * @dev: The PCI device.
   * @addr: The start address of the DMA region.
   * @size: The length of the DMA region.
   * @direction: The direction of the DMA transaction (to/from device).
   */
  static void 
  ccio_unmap_page(struct device *dev, dma_addr_t iova, size_t size,
  		enum dma_data_direction direction, unsigned long attrs)
  {
  	struct ioc *ioc;
  	unsigned long flags; 
  	dma_addr_t offset = iova & ~IOVP_MASK;
  	
  	BUG_ON(!dev);
  	ioc = GET_IOC(dev);
  	if (!ioc) {
  		WARN_ON(!ioc);
  		return;
  	}
  
  	DBG_RUN("%s() iovp 0x%lx/%x\n",
  		__func__, (long)iova, size);
  
  	iova ^= offset;        /* clear offset bits */
  	size += offset;
  	size = ALIGN(size, IOVP_SIZE);
  
  	spin_lock_irqsave(&ioc->res_lock, flags);
  
  #ifdef CCIO_COLLECT_STATS
  	ioc->usingle_calls++;
  	ioc->usingle_pages += size >> IOVP_SHIFT;
  #endif
  
  	ccio_mark_invalid(ioc, iova, size);
  	ccio_free_range(ioc, iova, (size >> IOVP_SHIFT));
  	spin_unlock_irqrestore(&ioc->res_lock, flags);
  }
  
  /**
   * ccio_alloc - Allocate a consistent DMA mapping.
   * @dev: The PCI device.
   * @size: The length of the DMA region.
   * @dma_handle: The DMA address handed back to the device (not the cpu).
   *
   * This function implements the pci_alloc_consistent function.
   */
  static void * 
  ccio_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t flag,
  		unsigned long attrs)
  {
        void *ret;
  #if 0
  /* GRANT Need to establish hierarchy for non-PCI devs as well
  ** and then provide matching gsc_map_xxx() functions for them as well.
  */
  	if(!hwdev) {
  		/* only support PCI */
  		*dma_handle = 0;
  		return 0;
  	}
  #endif
          ret = (void *) __get_free_pages(flag, get_order(size));
  
  	if (ret) {
  		memset(ret, 0, size);
  		*dma_handle = ccio_map_single(dev, ret, size, PCI_DMA_BIDIRECTIONAL);
  	}
  
  	return ret;
  }
  
  /**
   * ccio_free - Free a consistent DMA mapping.
   * @dev: The PCI device.
   * @size: The length of the DMA region.
   * @cpu_addr: The cpu address returned from the ccio_alloc_consistent.
   * @dma_handle: The device address returned from the ccio_alloc_consistent.
   *
   * This function implements the pci_free_consistent function.
   */
  static void 
  ccio_free(struct device *dev, size_t size, void *cpu_addr,
  		dma_addr_t dma_handle, unsigned long attrs)
  {
  	ccio_unmap_page(dev, dma_handle, size, 0, 0);
  	free_pages((unsigned long)cpu_addr, get_order(size));
  }
  
  /*
  ** Since 0 is a valid pdir_base index value, can't use that
  ** to determine if a value is valid or not. Use a flag to indicate
  ** the SG list entry contains a valid pdir index.
  */
  #define PIDE_FLAG 0x80000000UL
  
  #ifdef CCIO_COLLECT_STATS
  #define IOMMU_MAP_STATS
  #endif
  #include "iommu-helpers.h"
  
  /**
   * ccio_map_sg - Map the scatter/gather list into the IOMMU.
   * @dev: The PCI device.
   * @sglist: The scatter/gather list to be mapped in the IOMMU.
   * @nents: The number of entries in the scatter/gather list.
   * @direction: The direction of the DMA transaction (to/from device).
   *
   * This function implements the pci_map_sg function.
   */
  static int
  ccio_map_sg(struct device *dev, struct scatterlist *sglist, int nents, 
  	    enum dma_data_direction direction, unsigned long attrs)
  {
  	struct ioc *ioc;
  	int coalesced, filled = 0;
  	unsigned long flags;
  	unsigned long hint = hint_lookup[(int)direction];
  	unsigned long prev_len = 0, current_len = 0;
  	int i;
  	
  	BUG_ON(!dev);
  	ioc = GET_IOC(dev);
  	if (!ioc)
  		return 0;
  	
  	DBG_RUN_SG("%s() START %d entries\n", __func__, nents);
  
  	/* Fast path single entry scatterlists. */
  	if (nents == 1) {
  		sg_dma_address(sglist) = ccio_map_single(dev,
  				sg_virt(sglist), sglist->length,
  				direction);
  		sg_dma_len(sglist) = sglist->length;
  		return 1;
  	}
  
  	for(i = 0; i < nents; i++)
  		prev_len += sglist[i].length;
  	
  	spin_lock_irqsave(&ioc->res_lock, flags);
  
  #ifdef CCIO_COLLECT_STATS
  	ioc->msg_calls++;
  #endif
  
  	/*
  	** First coalesce the chunks and allocate I/O pdir space
  	**
  	** If this is one DMA stream, we can properly map using the
  	** correct virtual address associated with each DMA page.
  	** w/o this association, we wouldn't have coherent DMA!
  	** Access to the virtual address is what forces a two pass algorithm.
  	*/
  	coalesced = iommu_coalesce_chunks(ioc, dev, sglist, nents, ccio_alloc_range);
  
  	/*
  	** Program the I/O Pdir
  	**
  	** map the virtual addresses to the I/O Pdir
  	** o dma_address will contain the pdir index
  	** o dma_len will contain the number of bytes to map 
  	** o page/offset contain the virtual address.
  	*/
  	filled = iommu_fill_pdir(ioc, sglist, nents, hint, ccio_io_pdir_entry);
  
  	spin_unlock_irqrestore(&ioc->res_lock, flags);
  
  	BUG_ON(coalesced != filled);
  
  	DBG_RUN_SG("%s() DONE %d mappings\n", __func__, filled);
  
  	for (i = 0; i < filled; i++)
  		current_len += sg_dma_len(sglist + i);
  
  	BUG_ON(current_len != prev_len);
  
  	return filled;
  }
  
  /**
   * ccio_unmap_sg - Unmap the scatter/gather list from the IOMMU.
   * @dev: The PCI device.
   * @sglist: The scatter/gather list to be unmapped from the IOMMU.
   * @nents: The number of entries in the scatter/gather list.
   * @direction: The direction of the DMA transaction (to/from device).
   *
   * This function implements the pci_unmap_sg function.
   */
  static void 
  ccio_unmap_sg(struct device *dev, struct scatterlist *sglist, int nents, 
  	      enum dma_data_direction direction, unsigned long attrs)
  {
  	struct ioc *ioc;
  
  	BUG_ON(!dev);
  	ioc = GET_IOC(dev);
  	if (!ioc) {
  		WARN_ON(!ioc);
  		return;
  	}
  
  	DBG_RUN_SG("%s() START %d entries, %p,%x\n",
  		__func__, nents, sg_virt(sglist), sglist->length);
  
  #ifdef CCIO_COLLECT_STATS
  	ioc->usg_calls++;
  #endif
  
  	while(sg_dma_len(sglist) && nents--) {
  
  #ifdef CCIO_COLLECT_STATS
  		ioc->usg_pages += sg_dma_len(sglist) >> PAGE_SHIFT;
  #endif
  		ccio_unmap_page(dev, sg_dma_address(sglist),
  				  sg_dma_len(sglist), direction, 0);
  		++sglist;
  	}
  
  	DBG_RUN_SG("%s() DONE (nents %d)\n", __func__, nents);
  }
  
  static int ccio_mapping_error(struct device *dev, dma_addr_t dma_addr)
  {
  	return dma_addr == CCIO_MAPPING_ERROR;
  }
  
  static const struct dma_map_ops ccio_ops = {
  	.dma_supported =	ccio_dma_supported,
  	.alloc =		ccio_alloc,
  	.free =			ccio_free,
  	.map_page =		ccio_map_page,
  	.unmap_page =		ccio_unmap_page,
  	.map_sg = 		ccio_map_sg,
  	.unmap_sg = 		ccio_unmap_sg,
  	.mapping_error =	ccio_mapping_error,
  };
  
  #ifdef CONFIG_PROC_FS
  static int ccio_proc_info(struct seq_file *m, void *p)
  {
  	struct ioc *ioc = ioc_list;
  
  	while (ioc != NULL) {
  		unsigned int total_pages = ioc->res_size << 3;
  #ifdef CCIO_COLLECT_STATS
  		unsigned long avg = 0, min, max;
  		int j;
  #endif
  
  		seq_printf(m, "%s\n", ioc->name);
  		
  		seq_printf(m, "Cujo 2.0 bug    : %s\n",
  			   (ioc->cujo20_bug ? "yes" : "no"));
  		
  		seq_printf(m, "IO PDIR size    : %d bytes (%d entries)\n",
  			   total_pages * 8, total_pages);
  
  #ifdef CCIO_COLLECT_STATS
  		seq_printf(m, "IO PDIR entries : %ld free  %ld used (%d%%)\n",
  			   total_pages - ioc->used_pages, ioc->used_pages,
  			   (int)(ioc->used_pages * 100 / total_pages));
  #endif
  
  		seq_printf(m, "Resource bitmap : %d bytes (%d pages)\n",
  			   ioc->res_size, total_pages);
  
  #ifdef CCIO_COLLECT_STATS
  		min = max = ioc->avg_search[0];
  		for(j = 0; j < CCIO_SEARCH_SAMPLE; ++j) {
  			avg += ioc->avg_search[j];
  			if(ioc->avg_search[j] > max) 
  				max = ioc->avg_search[j];
  			if(ioc->avg_search[j] < min) 
  				min = ioc->avg_search[j];
  		}
  		avg /= CCIO_SEARCH_SAMPLE;
  		seq_printf(m, "  Bitmap search : %ld/%ld/%ld (min/avg/max CPU Cycles)\n",
  			   min, avg, max);
  
  		seq_printf(m, "pci_map_single(): %8ld calls  %8ld pages (avg %d/1000)\n",
  			   ioc->msingle_calls, ioc->msingle_pages,
  			   (int)((ioc->msingle_pages * 1000)/ioc->msingle_calls));
  
  		/* KLUGE - unmap_sg calls unmap_page for each mapped page */
  		min = ioc->usingle_calls - ioc->usg_calls;
  		max = ioc->usingle_pages - ioc->usg_pages;
  		seq_printf(m, "pci_unmap_single: %8ld calls  %8ld pages (avg %d/1000)\n",
  			   min, max, (int)((max * 1000)/min));
   
  		seq_printf(m, "pci_map_sg()    : %8ld calls  %8ld pages (avg %d/1000)\n",
  			   ioc->msg_calls, ioc->msg_pages,
  			   (int)((ioc->msg_pages * 1000)/ioc->msg_calls));
  
  		seq_printf(m, "pci_unmap_sg()  : %8ld calls  %8ld pages (avg %d/1000)\n\n\n",
  			   ioc->usg_calls, ioc->usg_pages,
  			   (int)((ioc->usg_pages * 1000)/ioc->usg_calls));
  #endif	/* CCIO_COLLECT_STATS */
  
  		ioc = ioc->next;
  	}
  
  	return 0;
  }
  
  static int ccio_proc_bitmap_info(struct seq_file *m, void *p)
  {
  	struct ioc *ioc = ioc_list;
  
  	while (ioc != NULL) {
  		seq_hex_dump(m, "   ", DUMP_PREFIX_NONE, 32, 4, ioc->res_map,
  			     ioc->res_size, false);
  		seq_putc(m, '\n');
  		ioc = ioc->next;
  		break; /* XXX - remove me */
  	}
  
  	return 0;
  }
  #endif /* CONFIG_PROC_FS */
  
  /**
   * ccio_find_ioc - Find the ioc in the ioc_list
   * @hw_path: The hardware path of the ioc.
   *
   * This function searches the ioc_list for an ioc that matches
   * the provide hardware path.
   */
  static struct ioc * ccio_find_ioc(int hw_path)
  {
  	int i;
  	struct ioc *ioc;
  
  	ioc = ioc_list;
  	for (i = 0; i < ioc_count; i++) {
  		if (ioc->hw_path == hw_path)
  			return ioc;
  
  		ioc = ioc->next;
  	}
  
  	return NULL;
  }
  
  /**
   * ccio_get_iommu - Find the iommu which controls this device
   * @dev: The parisc device.
   *
   * This function searches through the registered IOMMU's and returns
   * the appropriate IOMMU for the device based on its hardware path.
   */
  void * ccio_get_iommu(const struct parisc_device *dev)
  {
  	dev = find_pa_parent_type(dev, HPHW_IOA);
  	if (!dev)
  		return NULL;
  
  	return ccio_find_ioc(dev->hw_path);
  }
  
  #define CUJO_20_STEP       0x10000000	/* inc upper nibble */
  
  /* Cujo 2.0 has a bug which will silently corrupt data being transferred
   * to/from certain pages.  To avoid this happening, we mark these pages
   * as `used', and ensure that nothing will try to allocate from them.
   */
  void __init ccio_cujo20_fixup(struct parisc_device *cujo, u32 iovp)
  {
  	unsigned int idx;
  	struct parisc_device *dev = parisc_parent(cujo);
  	struct ioc *ioc = ccio_get_iommu(dev);
  	u8 *res_ptr;
  
  	ioc->cujo20_bug = 1;
  	res_ptr = ioc->res_map;
  	idx = PDIR_INDEX(iovp) >> 3;
  
  	while (idx < ioc->res_size) {
   		res_ptr[idx] |= 0xff;
  		idx += PDIR_INDEX(CUJO_20_STEP) >> 3;
  	}
  }
  
  #if 0
  /* GRANT -  is this needed for U2 or not? */
  
  /*
  ** Get the size of the I/O TLB for this I/O MMU.
  **
  ** If spa_shift is non-zero (ie probably U2),
  ** then calculate the I/O TLB size using spa_shift.
  **
  ** Otherwise we are supposed to get the IODC entry point ENTRY TLB
  ** and execute it. However, both U2 and Uturn firmware supplies spa_shift.
  ** I think only Java (K/D/R-class too?) systems don't do this.
  */
  static int
  ccio_get_iotlb_size(struct parisc_device *dev)
  {
  	if (dev->spa_shift == 0) {
  		panic("%s() : Can't determine I/O TLB size.\n", __func__);
  	}
  	return (1 << dev->spa_shift);
  }
  #else
  
  /* Uturn supports 256 TLB entries */
  #define CCIO_CHAINID_SHIFT	8
  #define CCIO_CHAINID_MASK	0xff
  #endif /* 0 */
  
  /* We *can't* support JAVA (T600). Venture there at your own risk. */
  static const struct parisc_device_id ccio_tbl[] __initconst = {
  	{ HPHW_IOA, HVERSION_REV_ANY_ID, U2_IOA_RUNWAY, 0xb }, /* U2 */
  	{ HPHW_IOA, HVERSION_REV_ANY_ID, UTURN_IOA_RUNWAY, 0xb }, /* UTurn */
  	{ 0, }
  };
  
  static int ccio_probe(struct parisc_device *dev);
  
  static struct parisc_driver ccio_driver __refdata = {
  	.name =		"ccio",
  	.id_table =	ccio_tbl,
  	.probe =	ccio_probe,
  };
  
  /**
   * ccio_ioc_init - Initialize the I/O Controller
   * @ioc: The I/O Controller.
   *
   * Initialize the I/O Controller which includes setting up the
   * I/O Page Directory, the resource map, and initalizing the
   * U2/Uturn chip into virtual mode.
   */
  static void __init
  ccio_ioc_init(struct ioc *ioc)
  {
  	int i;
  	unsigned int iov_order;
  	u32 iova_space_size;
  
  	/*
  	** Determine IOVA Space size from memory size.
  	**
  	** Ideally, PCI drivers would register the maximum number
  	** of DMA they can have outstanding for each device they
  	** own.  Next best thing would be to guess how much DMA
  	** can be outstanding based on PCI Class/sub-class. Both
  	** methods still require some "extra" to support PCI
  	** Hot-Plug/Removal of PCI cards. (aka PCI OLARD).
  	*/
  
  	iova_space_size = (u32) (totalram_pages / count_parisc_driver(&ccio_driver));
  
  	/* limit IOVA space size to 1MB-1GB */
  
  	if (iova_space_size < (1 << (20 - PAGE_SHIFT))) {
  		iova_space_size =  1 << (20 - PAGE_SHIFT);
  #ifdef __LP64__
  	} else if (iova_space_size > (1 << (30 - PAGE_SHIFT))) {
  		iova_space_size =  1 << (30 - PAGE_SHIFT);
  #endif
  	}
  
  	/*
  	** iova space must be log2() in size.
  	** thus, pdir/res_map will also be log2().
  	*/
  
  	/* We could use larger page sizes in order to *decrease* the number
  	** of mappings needed.  (ie 8k pages means 1/2 the mappings).
  	**
  	** Note: Grant Grunder says "Using 8k I/O pages isn't trivial either
  	**   since the pages must also be physically contiguous - typically
  	**   this is the case under linux."
  	*/
  
  	iov_order = get_order(iova_space_size << PAGE_SHIFT);
  
  	/* iova_space_size is now bytes, not pages */
  	iova_space_size = 1 << (iov_order + PAGE_SHIFT);
  
  	ioc->pdir_size = (iova_space_size / IOVP_SIZE) * sizeof(u64);
  
  	BUG_ON(ioc->pdir_size > 8 * 1024 * 1024);   /* max pdir size <= 8MB */
  
  	/* Verify it's a power of two */
  	BUG_ON((1 << get_order(ioc->pdir_size)) != (ioc->pdir_size >> PAGE_SHIFT));
  
  	DBG_INIT("%s() hpa 0x%p mem %luMB IOV %dMB (%d bits)\n",
  			__func__, ioc->ioc_regs,
  			(unsigned long) totalram_pages >> (20 - PAGE_SHIFT),
  			iova_space_size>>20,
  			iov_order + PAGE_SHIFT);
  
  	ioc->pdir_base = (u64 *)__get_free_pages(GFP_KERNEL, 
  						 get_order(ioc->pdir_size));
  	if(NULL == ioc->pdir_base) {
  		panic("%s() could not allocate I/O Page Table\n", __func__);
  	}
  	memset(ioc->pdir_base, 0, ioc->pdir_size);
  
  	BUG_ON((((unsigned long)ioc->pdir_base) & PAGE_MASK) != (unsigned long)ioc->pdir_base);
  	DBG_INIT(" base %p\n", ioc->pdir_base);
  
  	/* resource map size dictated by pdir_size */
   	ioc->res_size = (ioc->pdir_size / sizeof(u64)) >> 3;
  	DBG_INIT("%s() res_size 0x%x\n", __func__, ioc->res_size);
  	
  	ioc->res_map = (u8 *)__get_free_pages(GFP_KERNEL, 
  					      get_order(ioc->res_size));
  	if(NULL == ioc->res_map) {
  		panic("%s() could not allocate resource map\n", __func__);
  	}
  	memset(ioc->res_map, 0, ioc->res_size);
  
  	/* Initialize the res_hint to 16 */
  	ioc->res_hint = 16;
  
  	/* Initialize the spinlock */
  	spin_lock_init(&ioc->res_lock);
  
  	/*
  	** Chainid is the upper most bits of an IOVP used to determine
  	** which TLB entry an IOVP will use.
  	*/
  	ioc->chainid_shift = get_order(iova_space_size) + PAGE_SHIFT - CCIO_CHAINID_SHIFT;
  	DBG_INIT(" chainid_shift 0x%x\n", ioc->chainid_shift);
  
  	/*
  	** Initialize IOA hardware
  	*/
  	WRITE_U32(CCIO_CHAINID_MASK << ioc->chainid_shift, 
  		  &ioc->ioc_regs->io_chain_id_mask);
  
  	WRITE_U32(virt_to_phys(ioc->pdir_base), 
  		  &ioc->ioc_regs->io_pdir_base);
  
  	/*
  	** Go to "Virtual Mode"
  	*/
  	WRITE_U32(IOA_NORMAL_MODE, &ioc->ioc_regs->io_control);
  
  	/*
  	** Initialize all I/O TLB entries to 0 (Valid bit off).
  	*/
  	WRITE_U32(0, &ioc->ioc_regs->io_tlb_entry_m);
  	WRITE_U32(0, &ioc->ioc_regs->io_tlb_entry_l);
  
  	for(i = 1 << CCIO_CHAINID_SHIFT; i ; i--) {
  		WRITE_U32((CMD_TLB_DIRECT_WRITE | (i << ioc->chainid_shift)),
  			  &ioc->ioc_regs->io_command);
  	}
  }
  
  static void __init
  ccio_init_resource(struct resource *res, char *name, void __iomem *ioaddr)
  {
  	int result;
  
  	res->parent = NULL;
  	res->flags = IORESOURCE_MEM;
  	/*
  	 * bracing ((signed) ...) are required for 64bit kernel because
  	 * we only want to sign extend the lower 16 bits of the register.
  	 * The upper 16-bits of range registers are hardcoded to 0xffff.
  	 */
  	res->start = (unsigned long)((signed) READ_U32(ioaddr) << 16);
  	res->end = (unsigned long)((signed) (READ_U32(ioaddr + 4) << 16) - 1);
  	res->name = name;
  	/*
  	 * Check if this MMIO range is disable
  	 */
  	if (res->end + 1 == res->start)
  		return;
  
  	/* On some platforms (e.g. K-Class), we have already registered
  	 * resources for devices reported by firmware. Some are children
  	 * of ccio.
  	 * "insert" ccio ranges in the mmio hierarchy (/proc/iomem).
  	 */
  	result = insert_resource(&iomem_resource, res);
  	if (result < 0) {
  		printk(KERN_ERR "%s() failed to claim CCIO bus address space (%08lx,%08lx)\n", 
  			__func__, (unsigned long)res->start, (unsigned long)res->end);
  	}
  }
  
  static void __init ccio_init_resources(struct ioc *ioc)
  {
  	struct resource *res = ioc->mmio_region;
  	char *name = kmalloc(14, GFP_KERNEL);
  
  	snprintf(name, 14, "GSC Bus [%d/]", ioc->hw_path);
  
  	ccio_init_resource(res, name, &ioc->ioc_regs->io_io_low);
  	ccio_init_resource(res + 1, name, &ioc->ioc_regs->io_io_low_hv);
  }
  
  static int new_ioc_area(struct resource *res, unsigned long size,
  		unsigned long min, unsigned long max, unsigned long align)
  {
  	if (max <= min)
  		return -EBUSY;
  
  	res->start = (max - size + 1) &~ (align - 1);
  	res->end = res->start + size;
  	
  	/* We might be trying to expand the MMIO range to include
  	 * a child device that has already registered it's MMIO space.
  	 * Use "insert" instead of request_resource().
  	 */
  	if (!insert_resource(&iomem_resource, res))
  		return 0;
  
  	return new_ioc_area(res, size, min, max - size, align);
  }
  
  static int expand_ioc_area(struct resource *res, unsigned long size,
  		unsigned long min, unsigned long max, unsigned long align)
  {
  	unsigned long start, len;
  
  	if (!res->parent)
  		return new_ioc_area(res, size, min, max, align);
  
  	start = (res->start - size) &~ (align - 1);
  	len = res->end - start + 1;
  	if (start >= min) {
  		if (!adjust_resource(res, start, len))
  			return 0;
  	}
  
  	start = res->start;
  	len = ((size + res->end + align) &~ (align - 1)) - start;
  	if (start + len <= max) {
  		if (!adjust_resource(res, start, len))
  			return 0;
  	}
  
  	return -EBUSY;
  }
  
  /*
   * Dino calls this function.  Beware that we may get called on systems
   * which have no IOC (725, B180, C160L, etc) but do have a Dino.
   * So it's legal to find no parent IOC.
   *
   * Some other issues: one of the resources in the ioc may be unassigned.
   */
  int ccio_allocate_resource(const struct parisc_device *dev,
  		struct resource *res, unsigned long size,
  		unsigned long min, unsigned long max, unsigned long align)
  {
  	struct resource *parent = &iomem_resource;
  	struct ioc *ioc = ccio_get_iommu(dev);
  	if (!ioc)
  		goto out;
  
  	parent = ioc->mmio_region;
  	if (parent->parent &&
  	    !allocate_resource(parent, res, size, min, max, align, NULL, NULL))
  		return 0;
  
  	if ((parent + 1)->parent &&
  	    !allocate_resource(parent + 1, res, size, min, max, align,
  				NULL, NULL))
  		return 0;
  
  	if (!expand_ioc_area(parent, size, min, max, align)) {
  		__raw_writel(((parent->start)>>16) | 0xffff0000,
  			     &ioc->ioc_regs->io_io_low);
  		__raw_writel(((parent->end)>>16) | 0xffff0000,
  			     &ioc->ioc_regs->io_io_high);
  	} else if (!expand_ioc_area(parent + 1, size, min, max, align)) {
  		parent++;
  		__raw_writel(((parent->start)>>16) | 0xffff0000,
  			     &ioc->ioc_regs->io_io_low_hv);
  		__raw_writel(((parent->end)>>16) | 0xffff0000,
  			     &ioc->ioc_regs->io_io_high_hv);
  	} else {
  		return -EBUSY;
  	}
  
   out:
  	return allocate_resource(parent, res, size, min, max, align, NULL,NULL);
  }
  
  int ccio_request_resource(const struct parisc_device *dev,
  		struct resource *res)
  {
  	struct resource *parent;
  	struct ioc *ioc = ccio_get_iommu(dev);
  
  	if (!ioc) {
  		parent = &iomem_resource;
  	} else if ((ioc->mmio_region->start <= res->start) &&
  			(res->end <= ioc->mmio_region->end)) {
  		parent = ioc->mmio_region;
  	} else if (((ioc->mmio_region + 1)->start <= res->start) &&
  			(res->end <= (ioc->mmio_region + 1)->end)) {
  		parent = ioc->mmio_region + 1;
  	} else {
  		return -EBUSY;
  	}
  
  	/* "transparent" bus bridges need to register MMIO resources
  	 * firmware assigned them. e.g. children of hppb.c (e.g. K-class)
  	 * registered their resources in the PDC "bus walk" (See
  	 * arch/parisc/kernel/inventory.c).
  	 */
  	return insert_resource(parent, res);
  }
  
  /**
   * ccio_probe - Determine if ccio should claim this device.
   * @dev: The device which has been found
   *
   * Determine if ccio 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 __init ccio_probe(struct parisc_device *dev)
  {
  	int i;
  	struct ioc *ioc, **ioc_p = &ioc_list;
  
  	ioc = kzalloc(sizeof(struct ioc), GFP_KERNEL);
  	if (ioc == NULL) {
  		printk(KERN_ERR MODULE_NAME ": memory allocation failure\n");
  		return -ENOMEM;
  	}
  
  	ioc->name = dev->id.hversion == U2_IOA_RUNWAY ? "U2" : "UTurn";
  
  	printk(KERN_INFO "Found %s at 0x%lx\n", ioc->name,
  		(unsigned long)dev->hpa.start);
  
  	for (i = 0; i < ioc_count; i++) {
  		ioc_p = &(*ioc_p)->next;
  	}
  	*ioc_p = ioc;
  
  	ioc->hw_path = dev->hw_path;
  	ioc->ioc_regs = ioremap_nocache(dev->hpa.start, 4096);
  	if (!ioc->ioc_regs) {
  		kfree(ioc);
  		return -ENOMEM;
  	}
  	ccio_ioc_init(ioc);
  	ccio_init_resources(ioc);
  	hppa_dma_ops = &ccio_ops;
  	dev->dev.platform_data = kzalloc(sizeof(struct pci_hba_data), GFP_KERNEL);
  
  	/* if this fails, no I/O cards will work, so may as well bug */
  	BUG_ON(dev->dev.platform_data == NULL);
  	HBA_DATA(dev->dev.platform_data)->iommu = ioc;
  
  #ifdef CONFIG_PROC_FS
  	if (ioc_count == 0) {
  		proc_create_single(MODULE_NAME, 0, proc_runway_root,
  				ccio_proc_info);
  		proc_create_single(MODULE_NAME"-bitmap", 0, proc_runway_root,
  				ccio_proc_bitmap_info);
  	}
  #endif
  	ioc_count++;
  	return 0;
  }
  
  /**
   * ccio_init - ccio initialization procedure.
   *
   * Register this driver.
   */
  void __init ccio_init(void)
  {
  	register_parisc_driver(&ccio_driver);
  }
  
  