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 <asm/bmips.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 dma_addr_t __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 phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr) 56 { 57 struct bmips_dma_range *r; 58 59 for (r = bmips_dma_ranges; r && r->size; r++) { 60 if (dma_addr >= r->parent_addr && 61 dma_addr < (r->parent_addr + r->size)) 62 return dma_addr - r->parent_addr + r->child_addr; 63 } 64 return dma_addr; 65 } 66 67 void arch_sync_dma_for_cpu_all(void) 68 { 69 void __iomem *cbr = BMIPS_GET_CBR(); 70 u32 cfg; 71 72 if (boot_cpu_type() != CPU_BMIPS3300 && 73 boot_cpu_type() != CPU_BMIPS4350 && 74 boot_cpu_type() != CPU_BMIPS4380) 75 return; 76 77 /* Flush stale data out of the readahead cache */ 78 cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG); 79 __raw_writel(cfg | 0x100, cbr + BMIPS_RAC_CONFIG); 80 __raw_readl(cbr + BMIPS_RAC_CONFIG); 81 } 82 83 static int __init bmips_init_dma_ranges(void) 84 { 85 struct device_node *np = 86 of_find_compatible_node(NULL, NULL, "brcm,ubus"); 87 const __be32 *data; 88 struct bmips_dma_range *r; 89 int len; 90 91 if (!np) 92 return 0; 93 94 data = of_get_property(np, "dma-ranges", &len); 95 if (!data) 96 goto out_good; 97 98 len /= sizeof(*data) * 3; 99 if (!len) 100 goto out_bad; 101 102 /* add a dummy (zero) entry at the end as a sentinel */ 103 bmips_dma_ranges = kcalloc(len + 1, sizeof(struct bmips_dma_range), 104 GFP_KERNEL); 105 if (!bmips_dma_ranges) 106 goto out_bad; 107 108 for (r = bmips_dma_ranges; len; len--, r++) { 109 r->child_addr = be32_to_cpup(data++); 110 r->parent_addr = be32_to_cpup(data++); 111 r->size = be32_to_cpup(data++); 112 } 113 114 out_good: 115 of_node_put(np); 116 return 0; 117 118 out_bad: 119 pr_err("error parsing dma-ranges property\n"); 120 of_node_put(np); 121 return -EINVAL; 122 } 123 arch_initcall(bmips_init_dma_ranges); 124