LXR linux/arch/mips/bmips/dma.c

   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