1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 2014 Kevin Cernekee <cernekee@gmail.com> 7 */ 8 9 #define pr_fmt(fmt) "bmips-dma: " fmt 10 11 #include <linux/device.h> 12 #include <linux/dma-direction.h> 13 #include <linux/dma-mapping.h> 14 #include <linux/init.h> 15 #include <linux/io.h> 16 #include <linux/of.h> 17 #include <linux/printk.h> 18 #include <linux/slab.h> 19 #include <linux/types.h> 20 #include <dma-coherence.h> 21 22 /* 23 * BCM338x has configurable address translation windows which allow the 24 * peripherals' DMA addresses to be different from the Zephyr-visible 25 * physical addresses. e.g. usb_dma_addr = zephyr_pa ^ 0x08000000 26 * 27 * If the "brcm,ubus" node has a "dma-ranges" property we will enable this 28 * translation globally using the provided information. This implements a 29 * very limited subset of "dma-ranges" support and it will probably be 30 * replaced by a more generic version later. 31 */ 32 33 struct bmips_dma_range { 34 u32 child_addr; 35 u32 parent_addr; 36 u32 size; 37 }; 38 39 static struct bmips_dma_range *bmips_dma_ranges; 40 41 #define FLUSH_RAC 0x100 42 43 static dma_addr_t bmips_phys_to_dma(struct device *dev, phys_addr_t pa) 44 { 45 struct bmips_dma_range *r; 46 47 for (r = bmips_dma_ranges; r && r->size; r++) { 48 if (pa >= r->child_addr && 49 pa < (r->child_addr + r->size)) 50 return pa - r->child_addr + r->parent_addr; 51 } 52 return pa; 53 } 54 55 dma_addr_t plat_map_dma_mem(struct device *dev, void *addr, size_t size) 56 { 57 return bmips_phys_to_dma(dev, virt_to_phys(addr)); 58 } 59 60 dma_addr_t plat_map_dma_mem_page(struct device *dev, struct page *page) 61 { 62 return bmips_phys_to_dma(dev, page_to_phys(page)); 63 } 64 65 unsigned long plat_dma_addr_to_phys(struct device *dev, dma_addr_t dma_addr) 66 { 67 struct bmips_dma_range *r; 68 69 for (r = bmips_dma_ranges; r && r->size; r++) { 70 if (dma_addr >= r->parent_addr && 71 dma_addr < (r->parent_addr + r->size)) 72 return dma_addr - r->parent_addr + r->child_addr; 73 } 74 return dma_addr; 75 } 76 77 static int __init bmips_init_dma_ranges(void) 78 { 79 struct device_node *np = 80 of_find_compatible_node(NULL, NULL, "brcm,ubus"); 81 const __be32 *data; 82 struct bmips_dma_range *r; 83 int len; 84 85 if (!np) 86 return 0; 87 88 data = of_get_property(np, "dma-ranges", &len); 89 if (!data) 90 goto out_good; 91 92 len /= sizeof(*data) * 3; 93 if (!len) 94 goto out_bad; 95 96 /* add a dummy (zero) entry at the end as a sentinel */ 97 bmips_dma_ranges = kcalloc(len + 1, sizeof(struct bmips_dma_range), 98 GFP_KERNEL); 99 if (!bmips_dma_ranges) 100 goto out_bad; 101 102 for (r = bmips_dma_ranges; len; len--, r++) { 103 r->child_addr = be32_to_cpup(data++); 104 r->parent_addr = be32_to_cpup(data++); 105 r->size = be32_to_cpup(data++); 106 } 107 108 out_good: 109 of_node_put(np); 110 return 0; 111 112 out_bad: 113 pr_err("error parsing dma-ranges property\n"); 114 of_node_put(np); 115 return -EINVAL; 116 } 117 arch_initcall(bmips_init_dma_ranges); 118