1*4e0ee78fSHiroshi Doyu /* 2*4e0ee78fSHiroshi Doyu * OF helpers for IOMMU 3*4e0ee78fSHiroshi Doyu * 4*4e0ee78fSHiroshi Doyu * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved. 5*4e0ee78fSHiroshi Doyu * 6*4e0ee78fSHiroshi Doyu * This program is free software; you can redistribute it and/or modify it 7*4e0ee78fSHiroshi Doyu * under the terms and conditions of the GNU General Public License, 8*4e0ee78fSHiroshi Doyu * version 2, as published by the Free Software Foundation. 9*4e0ee78fSHiroshi Doyu * 10*4e0ee78fSHiroshi Doyu * This program is distributed in the hope it will be useful, but WITHOUT 11*4e0ee78fSHiroshi Doyu * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12*4e0ee78fSHiroshi Doyu * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 13*4e0ee78fSHiroshi Doyu * more details. 14*4e0ee78fSHiroshi Doyu * 15*4e0ee78fSHiroshi Doyu * You should have received a copy of the GNU General Public License along with 16*4e0ee78fSHiroshi Doyu * this program; if not, write to the Free Software Foundation, Inc., 17*4e0ee78fSHiroshi Doyu * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 18*4e0ee78fSHiroshi Doyu */ 19*4e0ee78fSHiroshi Doyu 20*4e0ee78fSHiroshi Doyu #include <linux/export.h> 21*4e0ee78fSHiroshi Doyu #include <linux/limits.h> 22*4e0ee78fSHiroshi Doyu #include <linux/of.h> 23*4e0ee78fSHiroshi Doyu 24*4e0ee78fSHiroshi Doyu /** 25*4e0ee78fSHiroshi Doyu * of_get_dma_window - Parse *dma-window property and returns 0 if found. 26*4e0ee78fSHiroshi Doyu * 27*4e0ee78fSHiroshi Doyu * @dn: device node 28*4e0ee78fSHiroshi Doyu * @prefix: prefix for property name if any 29*4e0ee78fSHiroshi Doyu * @index: index to start to parse 30*4e0ee78fSHiroshi Doyu * @busno: Returns busno if supported. Otherwise pass NULL 31*4e0ee78fSHiroshi Doyu * @addr: Returns address that DMA starts 32*4e0ee78fSHiroshi Doyu * @size: Returns the range that DMA can handle 33*4e0ee78fSHiroshi Doyu * 34*4e0ee78fSHiroshi Doyu * This supports different formats flexibly. "prefix" can be 35*4e0ee78fSHiroshi Doyu * configured if any. "busno" and "index" are optionally 36*4e0ee78fSHiroshi Doyu * specified. Set 0(or NULL) if not used. 37*4e0ee78fSHiroshi Doyu */ 38*4e0ee78fSHiroshi Doyu int of_get_dma_window(struct device_node *dn, const char *prefix, int index, 39*4e0ee78fSHiroshi Doyu unsigned long *busno, dma_addr_t *addr, size_t *size) 40*4e0ee78fSHiroshi Doyu { 41*4e0ee78fSHiroshi Doyu const __be32 *dma_window, *end; 42*4e0ee78fSHiroshi Doyu int bytes, cur_index = 0; 43*4e0ee78fSHiroshi Doyu char propname[NAME_MAX], addrname[NAME_MAX], sizename[NAME_MAX]; 44*4e0ee78fSHiroshi Doyu 45*4e0ee78fSHiroshi Doyu if (!dn || !addr || !size) 46*4e0ee78fSHiroshi Doyu return -EINVAL; 47*4e0ee78fSHiroshi Doyu 48*4e0ee78fSHiroshi Doyu if (!prefix) 49*4e0ee78fSHiroshi Doyu prefix = ""; 50*4e0ee78fSHiroshi Doyu 51*4e0ee78fSHiroshi Doyu snprintf(propname, sizeof(propname), "%sdma-window", prefix); 52*4e0ee78fSHiroshi Doyu snprintf(addrname, sizeof(addrname), "%s#dma-address-cells", prefix); 53*4e0ee78fSHiroshi Doyu snprintf(sizename, sizeof(sizename), "%s#dma-size-cells", prefix); 54*4e0ee78fSHiroshi Doyu 55*4e0ee78fSHiroshi Doyu dma_window = of_get_property(dn, propname, &bytes); 56*4e0ee78fSHiroshi Doyu if (!dma_window) 57*4e0ee78fSHiroshi Doyu return -ENODEV; 58*4e0ee78fSHiroshi Doyu end = dma_window + bytes / sizeof(*dma_window); 59*4e0ee78fSHiroshi Doyu 60*4e0ee78fSHiroshi Doyu while (dma_window < end) { 61*4e0ee78fSHiroshi Doyu u32 cells; 62*4e0ee78fSHiroshi Doyu const void *prop; 63*4e0ee78fSHiroshi Doyu 64*4e0ee78fSHiroshi Doyu /* busno is one cell if supported */ 65*4e0ee78fSHiroshi Doyu if (busno) 66*4e0ee78fSHiroshi Doyu *busno = be32_to_cpup(dma_window++); 67*4e0ee78fSHiroshi Doyu 68*4e0ee78fSHiroshi Doyu prop = of_get_property(dn, addrname, NULL); 69*4e0ee78fSHiroshi Doyu if (!prop) 70*4e0ee78fSHiroshi Doyu prop = of_get_property(dn, "#address-cells", NULL); 71*4e0ee78fSHiroshi Doyu 72*4e0ee78fSHiroshi Doyu cells = prop ? be32_to_cpup(prop) : of_n_addr_cells(dn); 73*4e0ee78fSHiroshi Doyu if (!cells) 74*4e0ee78fSHiroshi Doyu return -EINVAL; 75*4e0ee78fSHiroshi Doyu *addr = of_read_number(dma_window, cells); 76*4e0ee78fSHiroshi Doyu dma_window += cells; 77*4e0ee78fSHiroshi Doyu 78*4e0ee78fSHiroshi Doyu prop = of_get_property(dn, sizename, NULL); 79*4e0ee78fSHiroshi Doyu cells = prop ? be32_to_cpup(prop) : of_n_size_cells(dn); 80*4e0ee78fSHiroshi Doyu if (!cells) 81*4e0ee78fSHiroshi Doyu return -EINVAL; 82*4e0ee78fSHiroshi Doyu *size = of_read_number(dma_window, cells); 83*4e0ee78fSHiroshi Doyu dma_window += cells; 84*4e0ee78fSHiroshi Doyu 85*4e0ee78fSHiroshi Doyu if (cur_index++ == index) 86*4e0ee78fSHiroshi Doyu break; 87*4e0ee78fSHiroshi Doyu } 88*4e0ee78fSHiroshi Doyu return 0; 89*4e0ee78fSHiroshi Doyu } 90*4e0ee78fSHiroshi Doyu EXPORT_SYMBOL_GPL(of_get_dma_window); 91