xref: /kernel/linux/linux-5.10/arch/mips/bmips/dma.c (revision 8c2ecf20) 
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
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
43dma_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
55phys_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
67bool bmips_rac_flush_disable;
68
69void arch_sync_dma_for_cpu_all(void)
70{
71	void __iomem *cbr = BMIPS_GET_CBR();
72	u32 cfg;
73
74	if (boot_cpu_type() != CPU_BMIPS3300 &&
75	    boot_cpu_type() != CPU_BMIPS4350 &&
76	    boot_cpu_type() != CPU_BMIPS4380)
77		return;
78
79	if (unlikely(bmips_rac_flush_disable))
80		return;
81
82	/* Flush stale data out of the readahead cache */
83	cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
84	__raw_writel(cfg | 0x100, cbr + BMIPS_RAC_CONFIG);
85	__raw_readl(cbr + BMIPS_RAC_CONFIG);
86}
87
88static int __init bmips_init_dma_ranges(void)
89{
90	struct device_node *np =
91		of_find_compatible_node(NULL, NULL, "brcm,ubus");
92	const __be32 *data;
93	struct bmips_dma_range *r;
94	int len;
95
96	if (!np)
97		return 0;
98
99	data = of_get_property(np, "dma-ranges", &len);
100	if (!data)
101		goto out_good;
102
103	len /= sizeof(*data) * 3;
104	if (!len)
105		goto out_bad;
106
107	/* add a dummy (zero) entry at the end as a sentinel */
108	bmips_dma_ranges = kcalloc(len + 1, sizeof(struct bmips_dma_range),
109				   GFP_KERNEL);
110	if (!bmips_dma_ranges)
111		goto out_bad;
112
113	for (r = bmips_dma_ranges; len; len--, r++) {
114		r->child_addr = be32_to_cpup(data++);
115		r->parent_addr = be32_to_cpup(data++);
116		r->size = be32_to_cpup(data++);
117	}
118
119out_good:
120	of_node_put(np);
121	return 0;
122
123out_bad:
124	pr_err("error parsing dma-ranges property\n");
125	of_node_put(np);
126	return -EINVAL;
127}
128arch_initcall(bmips_init_dma_ranges);
129