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      1 /*	$NetBSD: isadma_machdep.c,v 1.17 2022/09/27 06:36:41 skrll Exp $	*/
      2 
      3 #define ISA_DMA_STATS
      4 
      5 /*-
      6  * Copyright (c) 1996, 1997, 1998 The NetBSD Foundation, Inc.
      7  * All rights reserved.
      8  *
      9  * This code is derived from software contributed to The NetBSD Foundation
     10  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
     11  * NASA Ames Research Center.
     12  *
     13  * Redistribution and use in source and binary forms, with or without
     14  * modification, are permitted provided that the following conditions
     15  * are met:
     16  * 1. Redistributions of source code must retain the above copyright
     17  *    notice, this list of conditions and the following disclaimer.
     18  * 2. Redistributions in binary form must reproduce the above copyright
     19  *    notice, this list of conditions and the following disclaimer in the
     20  *    documentation and/or other materials provided with the distribution.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     24  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     25  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     26  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     32  * POSSIBILITY OF SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 __KERNEL_RCSID(0, "$NetBSD: isadma_machdep.c,v 1.17 2022/09/27 06:36:41 skrll Exp $");
     37 
     38 #include <sys/param.h>
     39 #include <sys/systm.h>
     40 #include <sys/syslog.h>
     41 #include <sys/device.h>
     42 #include <sys/proc.h>
     43 #include <sys/mbuf.h>
     44 
     45 #define _ARM32_BUS_DMA_PRIVATE
     46 #include <sys/bus.h>
     47 
     48 #include <dev/isa/isareg.h>
     49 #include <dev/isa/isavar.h>
     50 
     51 #include <uvm/uvm_extern.h>
     52 
     53 /*
     54  * ISA has a 24-bit address limitation, so at most it has a 16M
     55  * DMA range.  However, some platforms have a more limited range,
     56  * e.g. the Shark NC.  On these systems, we are provided with
     57  * a set of DMA ranges.  The pmap module is aware of these ranges
     58  * and places DMA-safe memory for them onto an alternate free list
     59  * so that they are protected from being used to service page faults,
     60  * etc. (unless we've run out of memory elsewhere).
     61  */
     62 #define	ISA_DMA_BOUNCE_THRESHOLD	(16 * 1024 * 1024)
     63 
     64 struct arm32_dma_range *footbridge_isa_dma_ranges;
     65 int footbridge_isa_dma_nranges;
     66 
     67 /*
     68  * Entry points for ISA DMA.  These are mostly wrappers around
     69  * the generic functions that understand how to deal with bounce
     70  * buffers, if necessary.
     71  */
     72 struct arm32_bus_dma_tag isa_bus_dma_tag = {
     73 	_BUS_DMAMAP_FUNCS,
     74 	_BUS_DMAMEM_FUNCS,
     75 	_BUS_DMATAG_FUNCS,
     76 };
     77 
     78 /*
     79  * Initialize ISA DMA.
     80  */
     81 void
     82 isa_dma_init(void)
     83 {
     84 
     85 	isa_bus_dma_tag._ranges = footbridge_isa_dma_ranges;
     86 	isa_bus_dma_tag._nranges = footbridge_isa_dma_nranges;
     87 }
     88