arch/mips/powertv/ioremap.c

   1 /*
   2  *                      ioremap.c
   3  *
   4  * Support for mapping between dma_addr_t values a phys_addr_t values.
   5  *
   6  * Copyright (C) 2005-2009 Scientific-Atlanta, Inc.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  21  *
  22  * Author:       David VomLehn <dvomlehn@cisco.com>
  23  *
  24  * Description:  Defines the platform resources for the SA settop.
  25  *
  26  * NOTE: The bootloader allocates persistent memory at an address which is
  27  * 16 MiB below the end of the highest address in KSEG0. All fixed
  28  * address memory reservations must avoid this region.
  29  */
  30
  31 #include <linux/kernel.h>
  32 #include <linux/module.h>
  33
  34 #include <asm/mach-powertv/ioremap.h>
  35
  36 /*
  37  * Define the sizes of and masks for grains in physical and DMA space. The
  38  * values are the same but the types are not.
  39  */
  40 #define IOR_PHYS_GRAIN          ((phys_addr_t) 1 << IOR_LSBITS)
  41 #define IOR_PHYS_GRAIN_MASK     (IOR_PHYS_GRAIN - 1)
  42
  43 #define IOR_DMA_GRAIN           ((dma_addr_t) 1 << IOR_LSBITS)
  44 #define IOR_DMA_GRAIN_MASK      (IOR_DMA_GRAIN - 1)
  45
  46 /*
  47  * Values that, when accessed by an index derived from a phys_addr_t and
  48  * added to phys_addr_t value, yield a DMA address
  49  */
  50 struct ior_phys_to_dma _ior_phys_to_dma[IOR_NUM_PHYS_TO_DMA];
  51 EXPORT_SYMBOL(_ior_phys_to_dma);
  52
  53 /*
  54  * Values that, when accessed by an index derived from a dma_addr_t and
  55  * added to that dma_addr_t value, yield a physical address
  56  */
  57 struct ior_dma_to_phys _ior_dma_to_phys[IOR_NUM_DMA_TO_PHYS];
  58 EXPORT_SYMBOL(_ior_dma_to_phys);
  59
  60 /**
  61  * setup_dma_to_phys - set up conversion from DMA to physical addresses
  62  * @dma_idx:    Top IOR_LSBITS bits of the DMA address, i.e. an index
  63  *              into the array _dma_to_phys.
  64  * @delta:      Value that, when added to the DMA address, will yield the
  65  *              physical address
  66  * @s:          Number of bytes in the section of memory with the given delta
  67  *              between DMA and physical addresses.
  68  */
  69 static void setup_dma_to_phys(dma_addr_t dma, phys_addr_t delta, dma_addr_t s)
  70 {
  71         int dma_idx, first_idx, last_idx;
  72         phys_addr_t first, last;
  73
  74         /*
  75          * Calculate the first and last indices, rounding the first up and
  76          * the second down.
  77          */
  78         first = dma & ~IOR_DMA_GRAIN_MASK;
  79         last = (dma + s - 1) & ~IOR_DMA_GRAIN_MASK;
  80         first_idx = first >> IOR_LSBITS;                /* Convert to indices */
  81         last_idx = last >> IOR_LSBITS;
  82
  83         for (dma_idx = first_idx; dma_idx <= last_idx; dma_idx++)
  84                 _ior_dma_to_phys[dma_idx].offset = delta >> IOR_DMA_SHIFT;
  85 }
  86
  87 /**
  88  * setup_phys_to_dma - set up conversion from DMA to physical addresses
  89  * @phys_idx:   Top IOR_LSBITS bits of the DMA address, i.e. an index
  90  *              into the array _phys_to_dma.
  91  * @delta:      Value that, when added to the DMA address, will yield the
  92  *              physical address
  93  * @s:          Number of bytes in the section of memory with the given delta
  94  *              between DMA and physical addresses.
  95  */
  96 static void setup_phys_to_dma(phys_addr_t phys, dma_addr_t delta, phys_addr_t s)
  97 {
  98         int phys_idx, first_idx, last_idx;
  99         phys_addr_t first, last;
 100
 101         /*
 102          * Calculate the first and last indices, rounding the first up and
 103          * the second down.
 104          */
 105         first = phys & ~IOR_PHYS_GRAIN_MASK;
 106         last = (phys + s - 1) & ~IOR_PHYS_GRAIN_MASK;
 107         first_idx = first >> IOR_LSBITS;                /* Convert to indices */
 108         last_idx = last >> IOR_LSBITS;
 109
 110         for (phys_idx = first_idx; phys_idx <= last_idx; phys_idx++)
 111                 _ior_phys_to_dma[phys_idx].offset = delta >> IOR_PHYS_SHIFT;
 112 }
 113
 114 /**
 115  * ioremap_add_map - add to the physical and DMA address conversion arrays
 116  * @phys:       Process's view of the address of the start of the memory chunk
 117  * @dma:        DMA address of the start of the memory chunk
 118  * @size:       Size, in bytes, of the chunk of memory
 119  *
 120  * NOTE: It might be obvious, but the assumption is that all @size bytes have
 121  * the same offset between the physical address and the DMA address.
 122  */
 123 void ioremap_add_map(phys_addr_t phys, phys_addr_t dma, phys_addr_t size)
 124 {
 125         if (size == 0)
 126                 return;
 127
 128         if ((dma & IOR_DMA_GRAIN_MASK) != 0 ||
 129                 (phys & IOR_PHYS_GRAIN_MASK) != 0 ||
 130                 (size & IOR_PHYS_GRAIN_MASK) != 0)
 131                 pr_crit("Memory allocation must be in chunks of 0x%x bytes\n",
 132                         IOR_PHYS_GRAIN);
 133
 134         setup_dma_to_phys(dma, phys - dma, size);
 135         setup_phys_to_dma(phys, dma - phys, size);
 136 }