diff options
Diffstat (limited to 'sys/kern/subr_busdma_bufalloc.c')
-rw-r--r-- | sys/kern/subr_busdma_bufalloc.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/sys/kern/subr_busdma_bufalloc.c b/sys/kern/subr_busdma_bufalloc.c new file mode 100644 index 0000000..9406d95 --- /dev/null +++ b/sys/kern/subr_busdma_bufalloc.c @@ -0,0 +1,174 @@ +/*- + * Copyright (c) 2012 Ian Lepore + * 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. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * 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 <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * Buffer allocation support routines for bus_dmamem_alloc implementations. + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/bus.h> +#include <sys/busdma_bufalloc.h> +#include <sys/malloc.h> + +#include <vm/vm.h> +#include <vm/vm_extern.h> +#include <vm/vm_kern.h> +#include <vm/uma.h> + +/* + * We manage buffer zones up to a page in size. Buffers larger than a page can + * be managed by one of the kernel's page-oriented memory allocation routines as + * efficiently as what we can do here. Also, a page is the largest size for + * which we can g'tee contiguity when using uma, and contiguity is one of the + * requirements we have to fulfill. + */ +#define MIN_ZONE_BUFSIZE 32 +#define MAX_ZONE_BUFSIZE PAGE_SIZE + +/* + * The static array of 12 bufzones is big enough to handle all the zones for the + * smallest supported allocation size of 32 through the largest supported page + * size of 64K. If you up the biggest page size number, up the array size too. + * Basically the size of the array needs to be log2(maxsize)-log2(minsize)+1, + * but I don't know of an easy way to express that as a compile-time constant. + */ +#if PAGE_SIZE > 65536 +#error Unsupported page size +#endif + +struct busdma_bufalloc { + bus_size_t min_size; + size_t num_zones; + struct busdma_bufzone buf_zones[12]; +}; + +busdma_bufalloc_t +busdma_bufalloc_create(const char *name, bus_size_t minimum_alignment, + uma_alloc alloc_func, uma_free free_func, u_int32_t zcreate_flags) +{ + struct busdma_bufalloc *ba; + struct busdma_bufzone *bz; + int i; + bus_size_t cursize; + + ba = malloc(sizeof(struct busdma_bufalloc), M_DEVBUF, + M_ZERO | M_WAITOK); + + ba->min_size = MAX(MIN_ZONE_BUFSIZE, minimum_alignment); + + /* + * Each uma zone is created with an alignment of size-1, meaning that + * the alignment is equal to the size (I.E., 64 byte buffers are aligned + * to 64 byte boundaries, etc). This allows for a fast efficient test + * when deciding whether a pool buffer meets the constraints of a given + * tag used for allocation: the buffer is usable if tag->alignment <= + * bufzone->size. + */ + for (i = 0, bz = ba->buf_zones, cursize = ba->min_size; + i < nitems(ba->buf_zones) && cursize <= MAX_ZONE_BUFSIZE; + ++i, ++bz, cursize <<= 1) { + snprintf(bz->name, sizeof(bz->name), "dma %.10s %lu", + name, cursize); + bz->size = cursize; + bz->umazone = uma_zcreate(bz->name, bz->size, + NULL, NULL, NULL, NULL, bz->size - 1, zcreate_flags); + if (bz->umazone == NULL) { + busdma_bufalloc_destroy(ba); + return (NULL); + } + if (alloc_func != NULL) + uma_zone_set_allocf(bz->umazone, alloc_func); + if (free_func != NULL) + uma_zone_set_freef(bz->umazone, free_func); + ++ba->num_zones; + } + + return (ba); +} + +void +busdma_bufalloc_destroy(busdma_bufalloc_t ba) +{ + struct busdma_bufzone *bz; + int i; + + if (ba == NULL) + return; + + for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) { + uma_zdestroy(bz->umazone); + } + + free(ba, M_DEVBUF); +} + +struct busdma_bufzone * +busdma_bufalloc_findzone(busdma_bufalloc_t ba, bus_size_t size) +{ + struct busdma_bufzone *bz; + int i; + + if (size > MAX_ZONE_BUFSIZE) + return (NULL); + + for (i = 0, bz = ba->buf_zones; i < ba->num_zones; ++i, ++bz) { + if (bz->size >= size) + return (bz); + } + + panic("Didn't find a buffer zone of the right size"); +} + +void * +busdma_bufalloc_alloc_uncacheable(uma_zone_t zone, int size, u_int8_t *pflag, + int wait) +{ +#ifdef VM_MEMATTR_UNCACHEABLE + + /* Inform UMA that this allocator uses kernel_map/object. */ + *pflag = UMA_SLAB_KERNEL; + + return ((void *)kmem_alloc_attr(kernel_map, size, wait, 0, + BUS_SPACE_MAXADDR, VM_MEMATTR_UNCACHEABLE)); + +#else + + panic("VM_MEMATTR_UNCACHEABLE unavailable"); + +#endif /* VM_MEMATTR_UNCACHEABLE */ +} + +void +busdma_bufalloc_free_uncacheable(void *item, int size, u_int8_t pflag) +{ + + kmem_free(kernel_map, (vm_offset_t)item, size); +} + |