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
  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
  43 static 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
  55 dma_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
  60 dma_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
  65 unsigned 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
  77 static 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 = kcalloc(len + 1, sizeof(struct bmips_dma_range),
  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
 108 out_good:
 109         of_node_put(np);
 110         return 0;
 111
 112 out_bad:
 113         pr_err("error parsing dma-ranges property\n");
 114         of_node_put(np);
 115         return -EINVAL;
 116 }
 117 arch_initcall(bmips_init_dma_ranges);