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-direct.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);
 124