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/arch/mips/powertv/ioremap.c

http://github.com/mirrors/linux
C | 136 lines | 45 code | 15 blank | 76 comment | 8 complexity | e9718493faf2db0a60a1889cf72c69ea MD5 | raw file
  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 */
 50struct ior_phys_to_dma _ior_phys_to_dma[IOR_NUM_PHYS_TO_DMA];
 51EXPORT_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 */
 57struct ior_dma_to_phys _ior_dma_to_phys[IOR_NUM_DMA_TO_PHYS];
 58EXPORT_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 */
 69static 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 */
 96static 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 */
123void 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}