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