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
__phys_to_dma(struct device * dev,phys_addr_t pa)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
__dma_to_phys(struct device * dev,dma_addr_t dma_addr)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
arch_sync_dma_for_cpu_all(struct device * dev)67 void arch_sync_dma_for_cpu_all(struct device *dev)
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
bmips_init_dma_ranges(void)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