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
 67void 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
 83static 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
114out_good:
115	of_node_put(np);
116	return 0;
117
118out_bad:
119	pr_err("error parsing dma-ranges property\n");
120	of_node_put(np);
121	return -EINVAL;
122}
123arch_initcall(bmips_init_dma_ranges);