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
33struct bmips_dma_range {
34	u32			child_addr;
35	u32			parent_addr;
36	u32			size;
37};
38
39static struct bmips_dma_range *bmips_dma_ranges;
40
41#define FLUSH_RAC		0x100
42
43static 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
55dma_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
60dma_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
65unsigned 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
77static 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 = kzalloc(sizeof(struct bmips_dma_range) * (len + 1),
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
108out_good:
109	of_node_put(np);
110	return 0;
111
112out_bad:
113	pr_err("error parsing dma-ranges property\n");
114	of_node_put(np);
115	return -EINVAL;
116}
117arch_initcall(bmips_init_dma_ranges);
118