1 /* $OpenBSD: dma_alloc.c,v 1.12 2014/07/08 17:19:25 deraadt Exp $ */ 2 3 /* 4 * Copyright (c) 2010 Theo de Raadt <deraadt@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/param.h> 20 #include <sys/systm.h> 21 #include <sys/pool.h> 22 23 #include <uvm/uvm_extern.h> 24 25 static __inline int dma_alloc_index(size_t size); 26 27 /* Create dma pools from objects sized 2^4 to 2^16 */ 28 #define DMA_PAGE_SHIFT 16 29 #define DMA_BUCKET_OFFSET 4 30 static char dmanames[DMA_PAGE_SHIFT - DMA_BUCKET_OFFSET + 1][10]; 31 struct pool dmapools[DMA_PAGE_SHIFT - DMA_BUCKET_OFFSET + 1]; 32 33 void 34 dma_alloc_init(void) 35 { 36 int i; 37 38 for (i = 0; i < nitems(dmapools); i++) { 39 snprintf(dmanames[i], sizeof(dmanames[0]), "dma%d", 40 1 << (i + DMA_BUCKET_OFFSET)); 41 pool_init(&dmapools[i], 1 << (i + DMA_BUCKET_OFFSET), 0, 0, 0, 42 dmanames[i], NULL); 43 pool_set_constraints(&dmapools[i], &kp_dma_contig); 44 pool_setipl(&dmapools[i], IPL_VM); 45 /* XXX need pool_setlowat(&dmapools[i], dmalowat); */ 46 } 47 } 48 49 static __inline int 50 dma_alloc_index(size_t sz) 51 { 52 int b; 53 54 for (b = 0; b < nitems(dmapools); b++) 55 if (sz <= (1 << (b + DMA_BUCKET_OFFSET))) 56 return (b); 57 #ifdef DEBUG 58 printf("dma_alloc/free: object %zd too large\n", sz); 59 #endif 60 return (-1); 61 } 62 63 void * 64 dma_alloc(size_t size, int prflags) 65 { 66 int pi = dma_alloc_index(size); 67 68 if (pi == -1) 69 return (NULL); 70 return pool_get(&dmapools[pi], prflags); 71 } 72 73 74 void 75 dma_free(void *m, size_t size) 76 { 77 int pi = dma_alloc_index(size); 78 79 if (pi == -1) 80 return; 81 pool_put(&dmapools[pi], m); 82 } 83