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