source: rtems-libbsd/rtemsbsd/rtems/rtems-bsd-bus-dma.c @ fb683f7

/**
 * @file
 *
 * @ingroup rtems_bsd_rtems
 *
 * @brief TODO.
 *
 * File origin from FreeBSD "sys/powerpc/powerpc/busdma_machdep.c".
 */

/*
 * Copyright (c) 2009-2012 embedded brains GmbH.  
 * All rights reserved.
 *
 *  embedded brains GmbH
 *  Obere Lagerstr. 30
 *  82178 Puchheim
 *  Germany
 *  <rtems@embedded-brains.de>
 *
 * Copyright (c) 2004 Olivier Houchard
 * Copyright (c) 2002 Peter Grehan
 * Copyright (c) 1997, 1998 Justin T. Gibbs.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification, immediately at the beginning of the file.
 * 2. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <machine/rtems-bsd-kernel-space.h>
#include <machine/rtems-bsd-cache.h>
#include <machine/rtems-bsd-bus-dma.h>

#include <rtems/malloc.h>

#include <sys/malloc.h>
#include <machine/atomic.h>

#ifdef CPU_DATA_CACHE_ALIGNMENT
  #define CLSZ ((uintptr_t) CPU_DATA_CACHE_ALIGNMENT)
  #define CLMASK (CLSZ - (uintptr_t) 1)
#endif

/*
 * Convenience function for manipulating driver locks from busdma (during
 * busdma_swi, for example).  Drivers that don't provide their own locks
 * should specify &Giant to dmat->lockfuncarg.  Drivers that use their own
 * non-mutex locking scheme don't have to use this at all.
 */
void
busdma_lock_mutex(void *arg, bus_dma_lock_op_t op)
{
        struct mtx *dmtx;

        dmtx = (struct mtx *)arg;
        switch (op) {
        case BUS_DMA_LOCK:
                mtx_lock(dmtx);
                break;
        case BUS_DMA_UNLOCK:
                mtx_unlock(dmtx);
                break;
        default:
                panic("Unknown operation 0x%x for busdma_lock_mutex!", op);
        }
}

/*
 * dflt_lock should never get called.  It gets put into the dma tag when
 * lockfunc == NULL, which is only valid if the maps that are associated
 * with the tag are meant to never be defered.
 * XXX Should have a way to identify which driver is responsible here.
 */
static void
dflt_lock(void *arg, bus_dma_lock_op_t op)
{
        panic("driver error: busdma dflt_lock called");
}

/*
 * Allocate a device specific dma_tag.
 */
int
bus_dma_tag_create(bus_dma_tag_t parent, bus_size_t alignment,
    bus_size_t boundary, bus_addr_t lowaddr, bus_addr_t highaddr,
    bus_dma_filter_t *filter, void *filterarg, bus_size_t maxsize,
    int nsegments, bus_size_t maxsegsz, int flags, bus_dma_lock_t *lockfunc,
    void *lockfuncarg, bus_dma_tag_t *dmat)
{
        bus_dma_tag_t newtag;
        int error = 0;

        /* Return a NULL tag on failure */
        *dmat = NULL;

        newtag = malloc(sizeof(*newtag), M_DEVBUF, M_NOWAIT | M_ZERO);
        if (newtag == NULL)
                return (ENOMEM);

        newtag->parent = parent;
        newtag->alignment = alignment;
        newtag->boundary = boundary;
        newtag->lowaddr = lowaddr;
        newtag->highaddr = highaddr;
        newtag->filter = filter;
        newtag->filterarg = filterarg;
        newtag->maxsize = maxsize;
        newtag->nsegments = nsegments;
        newtag->maxsegsz = maxsegsz;
        newtag->flags = flags;
        newtag->ref_count = 1; /* Count ourself */
        newtag->map_count = 0;
        if (lockfunc != NULL) {
                newtag->lockfunc = lockfunc;
                newtag->lockfuncarg = lockfuncarg;
        } else {
                newtag->lockfunc = dflt_lock;
                newtag->lockfuncarg = NULL;
        }

        /*
         * Take into account any restrictions imposed by our parent tag
         */
        if (parent != NULL) {
                newtag->lowaddr = min(parent->lowaddr, newtag->lowaddr);
                newtag->highaddr = max(parent->highaddr, newtag->highaddr);
                if (newtag->boundary == 0)
                        newtag->boundary = parent->boundary;
                else if (parent->boundary != 0)
                        newtag->boundary = MIN(parent->boundary,
                                               newtag->boundary);
                if (newtag->filter == NULL) {
                        /*
                         * Short circuit looking at our parent directly
                         * since we have encapsulated all of its information
                         */
                        newtag->filter = parent->filter;
                        newtag->filterarg = parent->filterarg;
                        newtag->parent = parent->parent;
                }
                if (newtag->parent != NULL)
                        atomic_add_int(&parent->ref_count, 1);
        }

        *dmat = newtag;
        return (error);
}

int
bus_dma_tag_destroy(bus_dma_tag_t dmat)
{
        if (dmat != NULL) {

                if (dmat->map_count != 0)
                        return (EBUSY);

                while (dmat != NULL) {
                        bus_dma_tag_t parent;

                        parent = dmat->parent;
                        atomic_subtract_int(&dmat->ref_count, 1);
                        if (dmat->ref_count == 0) {
                                free(dmat, M_DEVBUF);
                                /*
                                 * Last reference count, so
                                 * release our reference
                                 * count on our parent.
                                 */
                                dmat = parent;
                        } else
                                dmat = NULL;
                }
        }
        return (0);
}

/*
 * Allocate a handle for mapping from kva/uva/physical
 * address space into bus device space.
 */
int
bus_dmamap_create(bus_dma_tag_t dmat, int flags, bus_dmamap_t *mapp)
{
        *mapp = malloc(sizeof(**mapp), M_DEVBUF, M_NOWAIT | M_ZERO);
        if (*mapp == NULL) {
                return ENOMEM;
        }

        dmat->map_count++;

        return (0);
}

/*
 * Destroy a handle for mapping from kva/uva/physical
 * address space into bus device space.
 */
int
bus_dmamap_destroy(bus_dma_tag_t dmat, bus_dmamap_t map)
{
        free(map, M_DEVBUF);

        dmat->map_count--;

        return (0);
}

/*
 * Allocate a piece of memory that can be efficiently mapped into
 * bus device space based on the constraints lited in the dma tag.
 * A dmamap to for use with dmamap_load is also allocated.
 */
int
bus_dmamem_alloc(bus_dma_tag_t dmat, void** vaddr, int flags,
    bus_dmamap_t *mapp)
{
        *mapp = malloc(sizeof(**mapp), M_DEVBUF, M_NOWAIT | M_ZERO);
        if (*mapp == NULL) {
                return ENOMEM;
        }

        if ((flags & BUS_DMA_COHERENT) != 0) {
                *vaddr = rtems_cache_coherent_allocate(
                    dmat->maxsize, dmat->alignment, dmat->boundary);
        } else {
                *vaddr = rtems_heap_allocate_aligned_with_boundary(
                    dmat->maxsize, dmat->alignment, dmat->boundary);
        }

        if (*vaddr == NULL) {
                free(*mapp, M_DEVBUF);

                return ENOMEM;
        }

        (*mapp)->buffer_begin = *vaddr;
        (*mapp)->buffer_size = dmat->maxsize;

        if ((flags & BUS_DMA_ZERO) != 0) {
                memset(*vaddr, 0, dmat->maxsize);
        }

        return (0);
}

/*
 * Free a piece of memory and it's allocated dmamap, that was allocated
 * via bus_dmamem_alloc.  Make the same choice for free/contigfree.
 */
void
bus_dmamem_free(bus_dma_tag_t dmat, void *vaddr, bus_dmamap_t map)
{
        rtems_cache_coherent_free(vaddr);
        free(map, M_DEVBUF);
}

/*
 * Utility function to load a linear buffer.  lastaddrp holds state
 * between invocations (for multiple-buffer loads).  segp contains
 * the starting segment on entrance, and the ending segment on exit.
 * first indicates if this is the first invocation of this function.
 */
int
bus_dmamap_load_buffer(bus_dma_tag_t dmat, bus_dma_segment_t segs[],
    void *buf, bus_size_t buflen, struct thread *td, int flags,
    vm_offset_t *lastaddrp, int *segp, int first)
{
        bus_size_t sgsize;
        bus_addr_t curaddr, lastaddr, baddr, bmask;
        vm_offset_t vaddr = (vm_offset_t)buf;
        int seg;

        lastaddr = *lastaddrp;
        bmask = ~(dmat->boundary - 1);

        for (seg = *segp; buflen > 0 ; ) {
                /*
                 * Get the physical address for this segment.
                 */
                curaddr = vaddr;

                /*
                 * Compute the segment size, and adjust counts.
                 */
                sgsize = PAGE_SIZE - ((u_long)curaddr & PAGE_MASK);
                if (sgsize > dmat->maxsegsz)
                        sgsize = dmat->maxsegsz;
                if (buflen < sgsize)
                        sgsize = buflen;

                /*
                 * Make sure we don't cross any boundaries.
                 */
                if (dmat->boundary > 0) {
                        baddr = (curaddr + dmat->boundary) & bmask;
                        if (sgsize > (baddr - curaddr))
                                sgsize = (baddr - curaddr);
                }

                /*
                 * Insert chunk into a segment, coalescing with
                 * the previous segment if possible.
                 */
                if (first) {
                        segs[seg].ds_addr = curaddr;
                        segs[seg].ds_len = sgsize;
                        first = 0;
                } else {
                        if (curaddr == lastaddr &&
                            (segs[seg].ds_len + sgsize) <= dmat->maxsegsz &&
                            (dmat->boundary == 0 ||
                             (segs[seg].ds_addr & bmask) == (curaddr & bmask)))
                                segs[seg].ds_len += sgsize;
                        else {
                                if (++seg >= dmat->nsegments)
                                        break;
                                segs[seg].ds_addr = curaddr;
                                segs[seg].ds_len = sgsize;
                        }
                }

                lastaddr = curaddr + sgsize;
                vaddr += sgsize;
                buflen -= sgsize;
        }

        *segp = seg;
        *lastaddrp = lastaddr;

        /*
         * Did we fit?
         */
        return (buflen != 0 ? EFBIG : 0); /* XXX better return value here? */
}

/*
 * Map the buffer buf into bus space using the dmamap map.
 */
int
bus_dmamap_load(bus_dma_tag_t dmat, bus_dmamap_t map, void *buf,
    bus_size_t buflen, bus_dmamap_callback_t *callback,
    void *callback_arg, int flags)
{
        bus_dma_segment_t       dm_segments[dmat->nsegments];
        vm_offset_t             lastaddr;
        int                     error, nsegs;

        map->buffer_begin = buf;
        map->buffer_size = buflen;

        lastaddr = (vm_offset_t)0;
        nsegs = 0;
        error = bus_dmamap_load_buffer(dmat, dm_segments, buf, buflen,
            NULL, flags, &lastaddr, &nsegs, 1);

        if (error == 0)
                (*callback)(callback_arg, dm_segments, nsegs + 1, 0);
        else
                (*callback)(callback_arg, NULL, 0, error);

        return (0);
}

/*
 * Release the mapping held by map. A no-op on PowerPC.
 */
void
_bus_dmamap_unload(bus_dma_tag_t dmat, bus_dmamap_t map)
{

        return;
}

void
_bus_dmamap_sync(bus_dma_tag_t dmat, bus_dmamap_t map, bus_dmasync_op_t op)
{
#ifdef CPU_DATA_CACHE_ALIGNMENT
        uintptr_t size = map->buffer_size;
        uintptr_t begin = (uintptr_t) map->buffer_begin;
        uintptr_t end = begin + size;

        if ((op & BUS_DMASYNC_PREWRITE) != 0 && (op & BUS_DMASYNC_PREREAD) == 0) {
                rtems_cache_flush_multiple_data_lines((void *) begin, size);
        }
        if ((op & BUS_DMASYNC_PREREAD) != 0) {
                if ((op & BUS_DMASYNC_PREWRITE) != 0 || ((begin | size) & CLMASK) != 0) {
                        rtems_cache_flush_multiple_data_lines((void *) begin, size);
                }
                rtems_cache_invalidate_multiple_data_lines((void *) begin, size);
        }
        if ((op & BUS_DMASYNC_POSTREAD) != 0) {
                char first_buf [CLSZ];
                char last_buf [CLSZ];
                bool first_is_aligned = (begin & CLMASK) == 0;
                bool last_is_aligned = (end & CLMASK) == 0;
                void *first_begin = (void *) (begin & ~CLMASK);
                size_t first_size = begin & CLMASK;
                void *last_begin = (void *) end;
                size_t last_size = CLSZ - (end & CLMASK);

                if (!first_is_aligned) {
                        memcpy(first_buf, first_begin, first_size);
                }
                if (!last_is_aligned) {
                        memcpy(last_buf, last_begin, last_size);
                }

                rtems_cache_invalidate_multiple_data_lines((void *) begin, size);

                if (!first_is_aligned) {
                        memcpy(first_begin, first_buf, first_size);
                }
                if (!last_is_aligned) {
                        memcpy(last_begin, last_buf, last_size);
                }
        }
#endif /* CPU_DATA_CACHE_ALIGNMENT */
}