1/*- 2 * Copyright (c) 2012 Ian Lepore 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27/* 28 * $FreeBSD$ 29 */ 30 31/* 32 * A buffer pool manager, for use by a platform's busdma implementation. 33 */ 34 35#ifndef _MACHINE_BUSDMA_BUFALLOC_H_ 36#define _MACHINE_BUSDMA_BUFALLOC_H_ 37 38#include <machine/bus.h> 39#include <vm/uma.h> 40 41/* 42 * Information about a buffer zone, returned by busdma_bufalloc_findzone(). 43 */ 44struct busdma_bufzone { 45 bus_size_t size; 46 uma_zone_t umazone; 47 char name[24]; 48}; 49 50/* 51 * Opaque handle type returned by busdma_bufalloc_create(). 52 */ 53struct busdma_bufalloc; 54typedef struct busdma_bufalloc *busdma_bufalloc_t; 55 56/* 57 * Create an allocator that manages a pool of DMA buffers. 58 * 59 * The allocator manages a collection of uma(9) zones of buffers in power-of-two 60 * sized increments ranging from minimum_alignment to the platform's PAGE_SIZE. 61 * The buffers within each zone are aligned on boundaries corresponding to the 62 * buffer size, and thus by implication each buffer is contiguous within a page 63 * and does not cross a power of two boundary larger than the buffer size. 64 * These rules are intended to make it easy for a busdma implementation to 65 * check whether a tag's constraints allow use of a buffer from the allocator. 66 * 67 * minimum_alignment is also the minimum buffer allocation size. For platforms 68 * with software-assisted cache coherency, this is typically the data cache line 69 * size (and MUST not be smaller than the cache line size). 70 * 71 * name appears in zone stats as 'dma name nnnnn' where 'dma' is fixed and 72 * 'nnnnn' is the size of buffers in that zone. 73 * 74 * If if the alloc/free function pointers are NULL, the regular uma internal 75 * allocators are used (I.E., you get "plain old kernel memory"). On a platform 76 * with an exclusion zone that applies to all DMA operations, a custom allocator 77 * could be used to ensure no buffer memory is ever allocated from that zone, 78 * allowing the bus_dmamem_alloc() implementation to make the assumption that 79 * buffers provided by the allocation could never lead to the need for a bounce. 80 */ 81busdma_bufalloc_t busdma_bufalloc_create(const char *name, 82 bus_size_t minimum_alignment, 83 uma_alloc uma_alloc_func, uma_free uma_free_func, 84 u_int32_t uma_zcreate_flags); 85 86/* 87 * Destroy an allocator created by busdma_bufalloc_create(). 88 * Safe to call with a NULL pointer. 89 */ 90void busdma_bufalloc_destroy(busdma_bufalloc_t ba); 91 92/* 93 * Return a pointer to the busdma_bufzone that should be used to allocate or 94 * free a buffer of the given size. Returns NULL if the size is larger than the 95 * largest zone handled by the allocator. 96 */ 97struct busdma_bufzone * busdma_bufalloc_findzone(busdma_bufalloc_t ba, 98 bus_size_t size); 99 100/* 101 * These built-in allocation routines are available for managing a pools of 102 * uncacheable memory on platforms that support VM_MEMATTR_UNCACHEABLE. 103 * 104 * Allocation is done using kmem_alloc_attr() with these parameters: 105 * lowaddr = 0 106 * highaddr = BUS_SPACE_MAXADDR 107 * memattr = VM_MEMATTR_UNCACHEABLE. 108 * 109 * If your platform has no exclusion region (lowaddr/highaddr), and its pmap 110 * routines support pmap_page_set_memattr() and the VM_MEMATTR_UNCACHEABLE flag 111 * you can probably use these when you need uncacheable buffers. 112 */ 113void * busdma_bufalloc_alloc_uncacheable(uma_zone_t zone, vm_size_t size, 114 uint8_t *pflag, int wait); 115void busdma_bufalloc_free_uncacheable(void *item, vm_size_t size, 116 uint8_t pflag); 117 118#endif /* _MACHINE_BUSDMA_BUFALLOC_H_ */ 119 120