patch-2.4.22 linux-2.4.22/arch/ia64/sn/io/alenlist.c
Next file: linux-2.4.22/arch/ia64/sn/io/ate_utils.c
Previous file: linux-2.4.22/arch/ia64/sn/io/Makefile
Back to the patch index
Back to the overall index
- Lines: 900
- Date:
1969-12-31 16:00:00.000000000 -0800
- Orig file:
linux-2.4.21/arch/ia64/sn/io/alenlist.c
- Orig date:
2002-08-02 17:39:42.000000000 -0700
diff -urN linux-2.4.21/arch/ia64/sn/io/alenlist.c linux-2.4.22/arch/ia64/sn/io/alenlist.c
@@ -1,899 +0,0 @@
-/* $Id$
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1992 - 1997, 2000-2002 Silicon Graphics, Inc. All rights reserved.
- */
-
-/* Implementation of Address/Length Lists. */
-
-
-#include <linux/types.h>
-#include <linux/slab.h>
-#include <linux/mmzone.h>
-#include <asm/sn/sgi.h>
-#include <asm/sn/alenlist.h>
-
-/*
- * Logically, an Address/Length List is a list of Pairs, where each pair
- * holds an Address and a Length, all in some Address Space. In this
- * context, "Address Space" is a particular Crosstalk Widget address
- * space, a PCI device address space, a VME bus address space, a
- * physical memory address space, etc.
- *
- * The main use for these Lists is to provide a single mechanism that
- * describes where in an address space a DMA occurs. This allows the
- * various I/O Bus support layers to provide a single interface for
- * DMA mapping and DMA translation without regard to how the DMA target
- * was specified by upper layers. The upper layers commonly specify a
- * DMA target via a buf structure page list, a kernel virtual address,
- * a user virtual address, a vector of addresses (a la uio and iov),
- * or possibly a pfn list.
- *
- * Address/Length Lists also enable drivers to take advantage of their
- * inate scatter/gather capabilities in systems where some address
- * translation may be required between bus adapters. The driver forms
- * a List that represents physical memory targets. This list is passed
- * to the various adapters, which apply various translations. The final
- * list that's returned to the driver is in terms of its local address
- * address space -- addresses which can be passed off to a scatter/gather
- * capable DMA controller.
- *
- * The current implementation is intended to be useful both in kernels
- * that support interrupt threads (INTR_KTHREAD) and in systems that do
- * not support interrupt threads. Of course, in the latter case, some
- * interfaces can be called only within a suspendable context.
- *
- * Basic operations on Address/Length Lists include:
- * alenlist_create Create a list
- * alenlist_clear Clear a list
- * alenlist_destroy Destroy a list
- * alenlist_append Append a Pair to the end of a list
- * alenlist_replace Replace a Pair in the middle of a list
- * alenlist_get Get an Address/Length Pair from a list
- * alenlist_size Return the number of Pairs in a list
- * alenlist_concat Append one list to the end of another
- * alenlist_clone Create a new copy of a list
- *
- * Operations that convert from upper-level specifications to Address/
- * Length Lists currently include:
- * kvaddr_to_alenlist Convert from a kernel virtual address
- * uvaddr_to_alenlist Convert from a user virtual address
- * buf_to_alenlist Convert from a buf structure
- * alenlist_done Tell system that we're done with an alenlist
- * obtained from a conversion.
- * Additional convenience operations:
- * alenpair_init Create a list and initialize it with a Pair
- * alenpair_get Peek at the first pair on a List
- *
- * A supporting type for Address/Length Lists is an alenlist_cursor_t. A
- * cursor marks a position in a List, and determines which Pair is fetched
- * by alenlist_get.
- * alenlist_cursor_create Allocate and initialize a cursor
- * alenlist_cursor_destroy Free space consumed by a cursor
- * alenlist_cursor_init (Re-)Initialize a cursor to point
- * to the start of a list
- * alenlist_cursor_clone Clone a cursor (at the current offset)
- * alenlist_cursor_offset Return the number of bytes into
- * a list that this cursor marks
- * Multiple cursors can point at various points into a List. Also, each
- * list maintains one "internal cursor" which may be updated by alenlist_clear
- * and alenlist_get. If calling code simply wishes to scan sequentially
- * through a list starting at the beginning, and if it is the only user of
- * a list, it can rely on this internal cursor rather than managing a
- * separate explicit cursor.
- *
- * The current implementation allows callers to allocate both cursors and
- * the lists as local stack (structure) variables. This allows for some
- * extra efficiency at the expense of forward binary compatibility. It
- * is recommended that customer drivers refrain from local allocation.
- * In fact, we likely will choose to move the structures out of the public
- * header file into a private place in order to discourage this usage.
- *
- * Currently, no locking is provided by the alenlist implementation.
- *
- * Implementation notes:
- * For efficiency, Pairs are grouped into "chunks" of, say, 32 Pairs
- * and a List consists of some number of these chunks. Chunks are completely
- * invisible to calling code. Chunks should be large enough to hold most
- * standard-sized DMA's, but not so large that they consume excessive space.
- *
- * It is generally expected that Lists will be constructed at one time and
- * scanned at a later time. It is NOT expected that drivers will scan
- * a List while the List is simultaneously extended, although this is
- * theoretically possible with sufficient upper-level locking.
- *
- * In order to support demands of Real-Time drivers and in order to support
- * swapping under low-memory conditions, we support the concept of a
- * "pre-allocated fixed-sized List". After creating a List with
- * alenlist_create, a driver may explicitly grow the list (via "alenlist_grow")
- * to a specific number of Address/Length pairs. It is guaranteed that future
- * operations involving this list will never automatically grow the list
- * (i.e. if growth is ever required, the operation will fail). Additionally,
- * operations that use alenlist's (e.g. DMA operations) accept a flag which
- * causes processing to take place "in-situ"; that is, the input alenlist
- * entries are replaced with output alenlist entries. The combination of
- * pre-allocated Lists and in-situ processing allows us to avoid the
- * potential deadlock scenario where we sleep (waiting for memory) in the
- * swap out path.
- *
- * For debugging, we track the number of allocated Lists in alenlist_count
- * the number of allocated chunks in alenlist_chunk_count, and the number
- * of allocate cursors in alenlist_cursor_count. We also provide a debug
- * routine, alenlist_show, which dumps the contents of an Address/Length List.
- *
- * Currently, Lists are formed by drivers on-demand. Eventually, we may
- * associate an alenlist with a buf structure and keep it up to date as
- * we go along. In that case, buf_to_alenlist simply returns a pointer
- * to the existing List, and increments the Lists's reference count.
- * alenlist_done would decrement the reference count and destroys the List
- * if it was the last reference.
- *
- * Eventually alenlist's may allow better support for user-level scatter/
- * gather operations (e.g. via readv/writev): With proper support, we
- * could potentially handle a vector of reads with a single scatter/gather
- * DMA operation. This could be especially useful on NUMA systems where
- * there's more of a reason for users to use vector I/O operations.
- *
- * Eventually, alenlist's may replace kaio lists, vhand page lists,
- * buffer cache pfdat lists, DMA page lists, etc.
- */
-
-/* Opaque data types */
-
-/* An Address/Length pair. */
-typedef struct alen_s {
- alenaddr_t al_addr;
- size_t al_length;
-} alen_t;
-
-/*
- * Number of elements in one chunk of an Address/Length List.
- *
- * This size should be sufficient to hold at least an "average" size
- * DMA request. Must be at least 1, and should be a power of 2,
- * for efficiency.
- */
-#define ALEN_CHUNK_SZ ((512*1024)/NBPP)
-
-/*
- * A fixed-size set of Address/Length Pairs. Chunks of Pairs are strung together
- * to form a complete Address/Length List. Chunking is entirely hidden within the
- * alenlist implementation, and it simply makes allocation and growth of lists more
- * efficient.
- */
-typedef struct alenlist_chunk_s {
- alen_t alc_pair[ALEN_CHUNK_SZ];/* list of addr/len pairs */
- struct alenlist_chunk_s *alc_next; /* point to next chunk of pairs */
-} *alenlist_chunk_t;
-
-/*
- * An Address/Length List. An Address/Length List is allocated with alenlist_create.
- * Alternatively, a list can be allocated on the stack (local variable of type
- * alenlist_t) and initialized with alenpair_init or with a combination of
- * alenlist_clear and alenlist_append, etc. Code which statically allocates these
- * structures loses forward binary compatibility!
- *
- * A statically allocated List is sufficiently large to hold ALEN_CHUNK_SZ pairs.
- */
-struct alenlist_s {
- unsigned short al_flags;
- unsigned short al_logical_size; /* logical size of list, in pairs */
- unsigned short al_actual_size; /* actual size of list, in pairs */
- struct alenlist_chunk_s *al_last_chunk; /* pointer to last logical chunk */
- struct alenlist_cursor_s al_cursor; /* internal cursor */
- struct alenlist_chunk_s al_chunk; /* initial set of pairs */
- alenaddr_t al_compaction_address; /* used to compact pairs */
-};
-
-/* al_flags field */
-#define AL_FIXED_SIZE 0x1 /* List is pre-allocated, and of fixed size */
-
-
-zone_t *alenlist_zone = NULL;
-zone_t *alenlist_chunk_zone = NULL;
-zone_t *alenlist_cursor_zone = NULL;
-
-#if DEBUG
-int alenlist_count=0; /* Currently allocated Lists */
-int alenlist_chunk_count = 0; /* Currently allocated chunks */
-int alenlist_cursor_count = 0; /* Currently allocate cursors */
-#define INCR_COUNT(ptr) atomic_inc((ptr));
-#define DECR_COUNT(ptr) atomic_dec((ptr));
-#else
-#define INCR_COUNT(ptr)
-#define DECR_COUNT(ptr)
-#endif /* DEBUG */
-
-#if DEBUG
-static void alenlist_show(alenlist_t);
-#endif /* DEBUG */
-
-/*
- * Initialize Address/Length List management. One time initialization.
- */
-void
-alenlist_init(void)
-{
- alenlist_zone = snia_kmem_zone_init(sizeof(struct alenlist_s), "alenlist");
- alenlist_chunk_zone = snia_kmem_zone_init(sizeof(struct alenlist_chunk_s), "alchunk");
- alenlist_cursor_zone = snia_kmem_zone_init(sizeof(struct alenlist_cursor_s), "alcursor");
-#if DEBUG
- idbg_addfunc("alenshow", alenlist_show);
-#endif /* DEBUG */
-}
-
-
-/*
- * Initialize an Address/Length List cursor.
- */
-static void
-do_cursor_init(alenlist_t alenlist, alenlist_cursor_t cursorp)
-{
- cursorp->al_alenlist = alenlist;
- cursorp->al_offset = 0;
- cursorp->al_chunk = &alenlist->al_chunk;
- cursorp->al_index = 0;
- cursorp->al_bcount = 0;
-}
-
-
-/*
- * Create an Address/Length List, and clear it.
- * Set the cursor to the beginning.
- */
-alenlist_t
-alenlist_create(unsigned flags)
-{
- alenlist_t alenlist;
-
- alenlist = snia_kmem_zone_alloc(alenlist_zone, flags & AL_NOSLEEP ? VM_NOSLEEP : 0);
- if (alenlist) {
- INCR_COUNT(&alenlist_count);
-
- alenlist->al_flags = 0;
- alenlist->al_logical_size = 0;
- alenlist->al_actual_size = ALEN_CHUNK_SZ;
- alenlist->al_last_chunk = &alenlist->al_chunk;
- alenlist->al_chunk.alc_next = NULL;
- do_cursor_init(alenlist, &alenlist->al_cursor);
- }
-
- return(alenlist);
-}
-
-
-/*
- * Grow an Address/Length List so that all resources needed to contain
- * the specified number of Pairs are pre-allocated. An Address/Length
- * List that has been explicitly "grown" will never *automatically*
- * grow, shrink, or be destroyed.
- *
- * Pre-allocation is useful for Real-Time drivers and for drivers that
- * may be used along the swap-out path and therefore cannot afford to
- * sleep until memory is freed.
- *
- * The cursor is set to the beginning of the list.
- */
-int
-alenlist_grow(alenlist_t alenlist, size_t npairs)
-{
- /*
- * This interface should be used relatively rarely, so
- * the implementation is kept simple: We clear the List,
- * then append npairs bogus entries. Finally, we mark
- * the list as FIXED_SIZE and re-initialize the internal
- * cursor.
- */
-
- /*
- * Temporarily mark as non-fixed size, since we're about
- * to shrink and expand it.
- */
- alenlist->al_flags &= ~AL_FIXED_SIZE;
-
- /* Free whatever was in the alenlist. */
- alenlist_clear(alenlist);
-
- /* Allocate everything that we need via automatic expansion. */
- while (npairs--)
- if (alenlist_append(alenlist, 0, 0, AL_NOCOMPACT) == ALENLIST_FAILURE)
- return(ALENLIST_FAILURE);
-
- /* Now, mark as FIXED_SIZE */
- alenlist->al_flags |= AL_FIXED_SIZE;
-
- /* Clear out bogus entries */
- alenlist_clear(alenlist);
-
- /* Initialize internal cursor to the beginning */
- do_cursor_init(alenlist, &alenlist->al_cursor);
-
- return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Clear an Address/Length List so that it holds no pairs.
- */
-void
-alenlist_clear(alenlist_t alenlist)
-{
- alenlist_chunk_t chunk, freechunk;
-
- /*
- * If this List is not FIXED_SIZE, free all the
- * extra chunks.
- */
- if (!(alenlist->al_flags & AL_FIXED_SIZE)) {
- /* First, free any extension alenlist chunks */
- chunk = alenlist->al_chunk.alc_next;
- while (chunk) {
- freechunk = chunk;
- chunk = chunk->alc_next;
- snia_kmem_zone_free(alenlist_chunk_zone, freechunk);
- DECR_COUNT(&alenlist_chunk_count);
- }
- alenlist->al_actual_size = ALEN_CHUNK_SZ;
- alenlist->al_chunk.alc_next = NULL;
- }
-
- alenlist->al_logical_size = 0;
- alenlist->al_last_chunk = &alenlist->al_chunk;
- do_cursor_init(alenlist, &alenlist->al_cursor);
-}
-
-
-/*
- * Create and initialize an Address/Length Pair.
- * This is intended for degenerate lists, consisting of a single
- * address/length pair.
- */
-alenlist_t
-alenpair_init( alenaddr_t address,
- size_t length)
-{
- alenlist_t alenlist;
-
- alenlist = alenlist_create(0);
-
- alenlist->al_logical_size = 1;
- ASSERT(alenlist->al_last_chunk == &alenlist->al_chunk);
- alenlist->al_chunk.alc_pair[0].al_length = length;
- alenlist->al_chunk.alc_pair[0].al_addr = address;
-
- return(alenlist);
-}
-
-/*
- * Return address/length from a degenerate (1-pair) List, or
- * first pair from a larger list. Does NOT update the internal cursor,
- * so this is an easy way to peek at a start address.
- */
-int
-alenpair_get( alenlist_t alenlist,
- alenaddr_t *address,
- size_t *length)
-{
- if (alenlist->al_logical_size == 0)
- return(ALENLIST_FAILURE);
-
- *length = alenlist->al_chunk.alc_pair[0].al_length;
- *address = alenlist->al_chunk.alc_pair[0].al_addr;
- return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Destroy an Address/Length List.
- */
-void
-alenlist_destroy(alenlist_t alenlist)
-{
- if (alenlist == NULL)
- return;
-
- /*
- * Turn off FIXED_SIZE so this List can be
- * automatically shrunk.
- */
- alenlist->al_flags &= ~AL_FIXED_SIZE;
-
- /* Free extension chunks first */
- if (alenlist->al_chunk.alc_next)
- alenlist_clear(alenlist);
-
- /* Now, free the alenlist itself */
- snia_kmem_zone_free(alenlist_zone, alenlist);
- DECR_COUNT(&alenlist_count);
-}
-
-/*
- * Release an Address/Length List.
- * This is in preparation for a day when alenlist's may be longer-lived, and
- * perhaps associated with a buf structure. We'd add a reference count, and
- * this routine would decrement the count. For now, we create alenlist's on
- * on demand and free them when done. If the driver is not explicitly managing
- * a List for its own use, it should call alenlist_done rather than alenlist_destroy.
- */
-void
-alenlist_done(alenlist_t alenlist)
-{
- alenlist_destroy(alenlist);
-}
-
-
-/*
- * Append another address/length to the end of an Address/Length List,
- * growing the list if permitted and necessary.
- *
- * Returns: SUCCESS/FAILURE
- */
-int
-alenlist_append( alenlist_t alenlist, /* append to this list */
- alenaddr_t address, /* address to append */
- size_t length, /* length to append */
- unsigned flags)
-{
- alen_t *alenp;
- int index, last_index;
-
- index = alenlist->al_logical_size % ALEN_CHUNK_SZ;
-
- if ((alenlist->al_logical_size > 0)) {
- /*
- * See if we can compact this new pair in with the previous entry.
- * al_compaction_address holds that value that we'd need to see
- * in order to compact.
- */
- if (!(flags & AL_NOCOMPACT) &&
- (alenlist->al_compaction_address == address)) {
- last_index = (alenlist->al_logical_size-1) % ALEN_CHUNK_SZ;
- alenp = &(alenlist->al_last_chunk->alc_pair[last_index]);
- alenp->al_length += length;
- alenlist->al_compaction_address += length;
- return(ALENLIST_SUCCESS);
- }
-
- /*
- * If we're out of room in this chunk, move to a new chunk.
- */
- if (index == 0) {
- if (alenlist->al_flags & AL_FIXED_SIZE) {
- alenlist->al_last_chunk = alenlist->al_last_chunk->alc_next;
-
- /* If we're out of space in a FIXED_SIZE List, quit. */
- if (alenlist->al_last_chunk == NULL) {
- ASSERT(alenlist->al_logical_size == alenlist->al_actual_size);
- return(ALENLIST_FAILURE);
- }
- } else {
- alenlist_chunk_t new_chunk;
-
- new_chunk = snia_kmem_zone_alloc(alenlist_chunk_zone,
- flags & AL_NOSLEEP ? VM_NOSLEEP : 0);
-
- if (new_chunk == NULL)
- return(ALENLIST_FAILURE);
-
- alenlist->al_last_chunk->alc_next = new_chunk;
- new_chunk->alc_next = NULL;
- alenlist->al_last_chunk = new_chunk;
- alenlist->al_actual_size += ALEN_CHUNK_SZ;
- INCR_COUNT(&alenlist_chunk_count);
- }
- }
- }
-
- alenp = &(alenlist->al_last_chunk->alc_pair[index]);
- alenp->al_addr = address;
- alenp->al_length = length;
-
- alenlist->al_logical_size++;
- alenlist->al_compaction_address = address + length;
-
- return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Replace an item in an Address/Length List. Cursor is updated so
- * that alenlist_get will get the next item in the list. This interface
- * is not very useful for drivers; but it is useful to bus providers
- * that need to translate between address spaced in situ. The old Address
- * and Length are returned.
- */
-/* ARGSUSED */
-int
-alenlist_replace( alenlist_t alenlist, /* in: replace in this list */
- alenlist_cursor_t cursorp, /* inout: which item to replace */
- alenaddr_t *addrp, /* inout: address */
- size_t *lengthp, /* inout: length */
- unsigned flags)
-{
- alen_t *alenp;
- alenlist_chunk_t chunk;
- unsigned int index;
- size_t length;
- alenaddr_t addr;
-
- if ((addrp == NULL) || (lengthp == NULL))
- return(ALENLIST_FAILURE);
-
- if (alenlist->al_logical_size == 0)
- return(ALENLIST_FAILURE);
-
- addr = *addrp;
- length = *lengthp;
-
- /*
- * If no cursor explicitly specified, use the Address/Length List's
- * internal cursor.
- */
- if (cursorp == NULL)
- cursorp = &alenlist->al_cursor;
-
- chunk = cursorp->al_chunk;
- index = cursorp->al_index;
-
- ASSERT(cursorp->al_alenlist == alenlist);
- if (cursorp->al_alenlist != alenlist)
- return(ALENLIST_FAILURE);
-
- alenp = &chunk->alc_pair[index];
-
- /* Return old values */
- *addrp = alenp->al_length;
- *lengthp = alenp->al_addr;
-
- /* Set up new values */
- alenp->al_length = length;
- alenp->al_addr = addr;
-
- /* Update cursor to point to next item */
- cursorp->al_bcount = length;
-
- return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Initialize a cursor in order to walk an alenlist.
- * An alenlist_cursor always points to the last thing that was obtained
- * from the list. If al_chunk is NULL, then nothing has yet been obtained.
- *
- * Note: There is an "internal cursor" associated with every Address/Length List.
- * For users that scan sequentially through a List, it is more efficient to
- * simply use the internal cursor. The caller must insure that no other users
- * will simultaneously scan the List. The caller can reposition the internal
- * cursor by calling alenlist_cursor_init with a NULL cursorp.
- */
-int
-alenlist_cursor_init(alenlist_t alenlist, size_t offset, alenlist_cursor_t cursorp)
-{
- size_t byte_count;
-
- if (cursorp == NULL)
- cursorp = &alenlist->al_cursor;
-
- /* Get internal cursor's byte count for use as a hint.
- *
- * If the internal cursor points passed the point that we're interested in,
- * we need to seek forward from the beginning. Otherwise, we can seek forward
- * from the internal cursor.
- */
- if ((offset > 0) &&
- ((byte_count = alenlist_cursor_offset(alenlist, (alenlist_cursor_t)NULL)) <= offset)) {
- offset -= byte_count;
- alenlist_cursor_clone(alenlist, NULL, cursorp);
- } else
- do_cursor_init(alenlist, cursorp);
-
- /* We could easily speed this up, but it shouldn't be used very often. */
- while (offset != 0) {
- alenaddr_t addr;
- size_t length;
-
- if (alenlist_get(alenlist, cursorp, offset, &addr, &length, 0) != ALENLIST_SUCCESS)
- return(ALENLIST_FAILURE);
- offset -= length;
- }
- return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Copy a cursor. The source cursor is either an internal alenlist cursor
- * or an explicit cursor.
- */
-int
-alenlist_cursor_clone( alenlist_t alenlist,
- alenlist_cursor_t cursorp_in,
- alenlist_cursor_t cursorp_out)
-{
- ASSERT(cursorp_out);
-
- if (alenlist && cursorp_in)
- if (alenlist != cursorp_in->al_alenlist)
- return(ALENLIST_FAILURE);
-
- if (alenlist)
- *cursorp_out = alenlist->al_cursor; /* small structure copy */
- else if (cursorp_in)
- *cursorp_out = *cursorp_in; /* small structure copy */
- else
- return(ALENLIST_FAILURE); /* no source */
-
- return(ALENLIST_SUCCESS);
-}
-
-/*
- * Return the number of bytes passed so far according to the specified cursor.
- * If cursorp is NULL, use the alenlist's internal cursor.
- */
-size_t
-alenlist_cursor_offset(alenlist_t alenlist, alenlist_cursor_t cursorp)
-{
- ASSERT(!alenlist || !cursorp || (alenlist == cursorp->al_alenlist));
-
- if (cursorp == NULL) {
- ASSERT(alenlist);
- cursorp = &alenlist->al_cursor;
- }
-
- return(cursorp->al_offset);
-}
-
-/*
- * Allocate and initialize an Address/Length List cursor.
- */
-alenlist_cursor_t
-alenlist_cursor_create(alenlist_t alenlist, unsigned flags)
-{
- alenlist_cursor_t cursorp;
-
- ASSERT(alenlist != NULL);
- cursorp = snia_kmem_zone_alloc(alenlist_cursor_zone, flags & AL_NOSLEEP ? VM_NOSLEEP : 0);
- if (cursorp) {
- INCR_COUNT(&alenlist_cursor_count);
- alenlist_cursor_init(alenlist, 0, cursorp);
- }
- return(cursorp);
-}
-
-/*
- * Free an Address/Length List cursor.
- */
-void
-alenlist_cursor_destroy(alenlist_cursor_t cursorp)
-{
- DECR_COUNT(&alenlist_cursor_count);
- snia_kmem_zone_free(alenlist_cursor_zone, cursorp);
-}
-
-
-/*
- * Fetch an address/length pair from an Address/Length List. Update
- * the "cursor" so that next time this routine is called, we'll get
- * the next address range. Never return a length that exceeds maxlength
- * (if non-zero). If maxlength is a power of 2, never return a length
- * that crosses a maxlength boundary. [This may seem strange at first,
- * but it's what many drivers want.]
- *
- * Returns: SUCCESS/FAILURE
- */
-int
-alenlist_get( alenlist_t alenlist, /* in: get from this list */
- alenlist_cursor_t cursorp, /* inout: which item to get */
- size_t maxlength, /* in: at most this length */
- alenaddr_t *addrp, /* out: address */
- size_t *lengthp, /* out: length */
- unsigned flags)
-{
- alen_t *alenp;
- alenlist_chunk_t chunk;
- unsigned int index;
- size_t bcount;
- size_t length;
-
- /*
- * If no cursor explicitly specified, use the Address/Length List's
- * internal cursor.
- */
- if (cursorp == NULL) {
- if (alenlist->al_logical_size == 0)
- return(ALENLIST_FAILURE);
- cursorp = &alenlist->al_cursor;
- }
-
- chunk = cursorp->al_chunk;
- index = cursorp->al_index;
- bcount = cursorp->al_bcount;
-
- ASSERT(cursorp->al_alenlist == alenlist);
- if (cursorp->al_alenlist != alenlist)
- return(ALENLIST_FAILURE);
-
- alenp = &chunk->alc_pair[index];
- length = alenp->al_length - bcount;
-
- /* Bump up to next pair, if we're done with this pair. */
- if (length == 0) {
- cursorp->al_bcount = bcount = 0;
- cursorp->al_index = index = (index + 1) % ALEN_CHUNK_SZ;
-
- /* Bump up to next chunk, if we're done with this chunk. */
- if (index == 0) {
- if (cursorp->al_chunk == alenlist->al_last_chunk)
- return(ALENLIST_FAILURE);
- chunk = chunk->alc_next;
- ASSERT(chunk != NULL);
- } else {
- /* If in last chunk, don't go beyond end. */
- if (cursorp->al_chunk == alenlist->al_last_chunk) {
- int last_size = alenlist->al_logical_size % ALEN_CHUNK_SZ;
- if (last_size && (index >= last_size))
- return(ALENLIST_FAILURE);
- }
- }
-
- alenp = &chunk->alc_pair[index];
- length = alenp->al_length;
- }
-
- /* Constrain what we return according to maxlength */
- if (maxlength) {
- size_t maxlen1 = maxlength - 1;
-
- if ((maxlength & maxlen1) == 0) /* power of 2 */
- maxlength -=
- ((alenp->al_addr + cursorp->al_bcount) & maxlen1);
-
- length = min(maxlength, length);
- }
-
- /* Update the cursor, if desired. */
- if (!(flags & AL_LEAVE_CURSOR)) {
- cursorp->al_bcount += length;
- cursorp->al_chunk = chunk;
- }
-
- *lengthp = length;
- *addrp = alenp->al_addr + bcount;
-
- return(ALENLIST_SUCCESS);
-}
-
-
-/*
- * Return the number of pairs in the specified Address/Length List.
- * (For FIXED_SIZE Lists, this returns the logical size of the List,
- * not the actual capacity of the List.)
- */
-int
-alenlist_size(alenlist_t alenlist)
-{
- return(alenlist->al_logical_size);
-}
-
-
-/*
- * Concatenate two Address/Length Lists.
- */
-void
-alenlist_concat(alenlist_t from,
- alenlist_t to)
-{
- struct alenlist_cursor_s cursor;
- alenaddr_t addr;
- size_t length;
-
- alenlist_cursor_init(from, 0, &cursor);
-
- while(alenlist_get(from, &cursor, (size_t)0, &addr, &length, 0) == ALENLIST_SUCCESS)
- alenlist_append(to, addr, length, 0);
-}
-
-/*
- * Create a copy of a list.
- * (Not all attributes of the old list are cloned. For instance, if
- * a FIXED_SIZE list is cloned, the resulting list is NOT FIXED_SIZE.)
- */
-alenlist_t
-alenlist_clone(alenlist_t old_list, unsigned flags)
-{
- alenlist_t new_list;
-
- new_list = alenlist_create(flags);
- if (new_list != NULL)
- alenlist_concat(old_list, new_list);
-
- return(new_list);
-}
-
-
-/*
- * Convert a kernel virtual address to a Physical Address/Length List.
- */
-alenlist_t
-kvaddr_to_alenlist(alenlist_t alenlist, caddr_t kvaddr, size_t length, unsigned flags)
-{
- alenaddr_t paddr;
- long offset;
- size_t piece_length;
- int created_alenlist;
-
- if (length <=0)
- return(NULL);
-
- /* If caller supplied a List, use it. Otherwise, allocate one. */
- if (alenlist == NULL) {
- alenlist = alenlist_create(0);
- created_alenlist = 1;
- } else {
- alenlist_clear(alenlist);
- created_alenlist = 0;
- }
-
- paddr = kvtophys(kvaddr);
- offset = poff(kvaddr);
-
- /* Handle first page */
- piece_length = min((size_t)(NBPP - offset), length);
- if (alenlist_append(alenlist, paddr, piece_length, flags) == ALENLIST_FAILURE)
- goto failure;
- length -= piece_length;
- kvaddr += piece_length;
-
- /* Handle middle pages */
- while (length >= NBPP) {
- paddr = kvtophys(kvaddr);
- if (alenlist_append(alenlist, paddr, NBPP, flags) == ALENLIST_FAILURE)
- goto failure;
- length -= NBPP;
- kvaddr += NBPP;
- }
-
- /* Handle last page */
- if (length) {
- ASSERT(length < NBPP);
- paddr = kvtophys(kvaddr);
- if (alenlist_append(alenlist, paddr, length, flags) == ALENLIST_FAILURE)
- goto failure;
- }
-
- alenlist_cursor_init(alenlist, 0, NULL);
- return(alenlist);
-
-failure:
- if (created_alenlist)
- alenlist_destroy(alenlist);
- return(NULL);
-}
-
-
-#if DEBUG
-static void
-alenlist_show(alenlist_t alenlist)
-{
- struct alenlist_cursor_s cursor;
- alenaddr_t addr;
- size_t length;
- int i = 0;
-
- alenlist_cursor_init(alenlist, 0, &cursor);
-
- qprintf("Address/Length List@0x%x:\n", alenlist);
- qprintf("logical size=0x%x actual size=0x%x last_chunk at 0x%x\n",
- alenlist->al_logical_size, alenlist->al_actual_size,
- alenlist->al_last_chunk);
- qprintf("cursor: chunk=0x%x index=%d offset=0x%x\n",
- alenlist->al_cursor.al_chunk,
- alenlist->al_cursor.al_index,
- alenlist->al_cursor.al_bcount);
- while(alenlist_get(alenlist, &cursor, (size_t)0, &addr, &length, 0) == ALENLIST_SUCCESS)
- qprintf("%d:\t0x%lx 0x%lx\n", ++i, addr, length);
-}
-#endif /* DEBUG */
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)