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      1 /* $NetBSD: fdt_dma.c,v 1.4 2019/02/27 16:56:00 jakllsch Exp $ */
      2 
      3 /*-
      4  * Copyright (c) 2015 Jared D. McNeill <jmcneill (at) invisible.ca>
      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 ``AS IS'' AND ANY EXPRESS OR
     17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * 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 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: fdt_dma.c,v 1.4 2019/02/27 16:56:00 jakllsch Exp $");
     31 
     32 #include <sys/param.h>
     33 #include <sys/bus.h>
     34 #include <sys/kmem.h>
     35 #include <sys/queue.h>
     36 
     37 #include <libfdt.h>
     38 #include <dev/fdt/fdtvar.h>
     39 
     40 struct fdtbus_dma_controller {
     41 	device_t dma_dev;
     42 	int dma_phandle;
     43 	const struct fdtbus_dma_controller_func *dma_funcs;
     44 
     45 	LIST_ENTRY(fdtbus_dma_controller) dma_next;
     46 };
     47 
     48 static LIST_HEAD(, fdtbus_dma_controller) fdtbus_dma_controllers =
     49     LIST_HEAD_INITIALIZER(fdtbus_dma_controllers);
     50 
     51 int
     52 fdtbus_register_dma_controller(device_t dev, int phandle,
     53     const struct fdtbus_dma_controller_func *funcs)
     54 {
     55 	struct fdtbus_dma_controller *dma;
     56 
     57 	dma = kmem_alloc(sizeof(*dma), KM_SLEEP);
     58 	dma->dma_dev = dev;
     59 	dma->dma_phandle = phandle;
     60 	dma->dma_funcs = funcs;
     61 
     62 	LIST_INSERT_HEAD(&fdtbus_dma_controllers, dma, dma_next);
     63 
     64 	return 0;
     65 }
     66 
     67 static struct fdtbus_dma_controller *
     68 fdtbus_get_dma_controller(int phandle)
     69 {
     70 	struct fdtbus_dma_controller *dma;
     71 
     72 	LIST_FOREACH(dma, &fdtbus_dma_controllers, dma_next) {
     73 		if (dma->dma_phandle == phandle)
     74 			return dma;
     75 	}
     76 
     77 	return NULL;
     78 }
     79 
     80 struct fdtbus_dma *
     81 fdtbus_dma_get_index(int phandle, u_int index, void (*cb)(void *), void *cbarg)
     82 {
     83 	struct fdtbus_dma_controller *dc;
     84 	struct fdtbus_dma *dma = NULL;
     85 	void *dma_priv = NULL;
     86 	uint32_t *dmas = NULL;
     87 	uint32_t *p;
     88 	u_int n, dma_cells;
     89 	int len, resid;
     90 
     91 	len = OF_getproplen(phandle, "dmas");
     92 	if (len <= 0)
     93 		return NULL;
     94 
     95 	dmas = kmem_alloc(len, KM_SLEEP);
     96 	if (OF_getprop(phandle, "dmas", dmas, len) != len) {
     97 		kmem_free(dmas, len);
     98 		return NULL;
     99 	}
    100 
    101 	p = dmas;
    102 	for (n = 0, resid = len; resid > 0; n++) {
    103 		const int dc_phandle =
    104 		    fdtbus_get_phandle_from_native(be32toh(p[0]));
    105 		if (of_getprop_uint32(dc_phandle, "#dma-cells", &dma_cells))
    106 			break;
    107 		if (n == index) {
    108 			dc = fdtbus_get_dma_controller(dc_phandle);
    109 			if (dc == NULL)
    110 				goto done;
    111 			dma_priv = dc->dma_funcs->acquire(dc->dma_dev,
    112 			    dma_cells > 0 ? &p[1] : NULL, dma_cells * 4,
    113 			    cb, cbarg);
    114 			if (dma_priv) {
    115 				dma = kmem_alloc(sizeof(*dma), KM_SLEEP);
    116 				dma->dma_dc = dc;
    117 				dma->dma_priv = dma_priv;
    118 			}
    119 			break;
    120 		}
    121 		resid -= (dma_cells + 1) * 4;
    122 		p += dma_cells + 1;
    123 	}
    124 
    125 done:
    126 	if (dmas)
    127 		kmem_free(dmas, len);
    128 
    129 	return dma;
    130 }
    131 
    132 struct fdtbus_dma *
    133 fdtbus_dma_get(int phandle, const char *name, void (*cb)(void *), void *cbarg)
    134 {
    135 	u_int index;
    136 	int err;
    137 
    138 	err = fdtbus_get_index(phandle, "dma-names", name, &index);
    139 	if (err != 0)
    140 		return NULL;
    141 
    142 	return fdtbus_dma_get_index(phandle, index, cb, cbarg);
    143 }
    144 
    145 void
    146 fdtbus_dma_put(struct fdtbus_dma *dma)
    147 {
    148 	struct fdtbus_dma_controller *dc = dma->dma_dc;
    149 
    150 	dc->dma_funcs->release(dc->dma_dev, dma->dma_priv);
    151 	kmem_free(dma, sizeof(*dma));
    152 }
    153 
    154 int
    155 fdtbus_dma_transfer(struct fdtbus_dma *dma, struct fdtbus_dma_req *req)
    156 {
    157 	struct fdtbus_dma_controller *dc = dma->dma_dc;
    158 
    159 	return dc->dma_funcs->transfer(dc->dma_dev, dma->dma_priv, req);
    160 }
    161 
    162 void
    163 fdtbus_dma_halt(struct fdtbus_dma *dma)
    164 {
    165 	struct fdtbus_dma_controller *dc = dma->dma_dc;
    166 
    167 	return dc->dma_funcs->halt(dc->dma_dev, dma->dma_priv);
    168 }
    169