ioremap.c

  1/*
  2 * arch/sh/mm/ioremap.c
  3 *
  4 * (C) Copyright 1995 1996 Linus Torvalds
  5 * (C) Copyright 2005 - 2010  Paul Mundt
  6 *
  7 * Re-map IO memory to kernel address space so that we can access it.
  8 * This is needed for high PCI addresses that aren't mapped in the
  9 * 640k-1MB IO memory area on PC's
 10 *
 11 * This file is subject to the terms and conditions of the GNU General
 12 * Public License. See the file "COPYING" in the main directory of this
 13 * archive for more details.
 14 */
 15#include <linux/vmalloc.h>
 16#include <linux/module.h>
 17#include <linux/slab.h>
 18#include <linux/mm.h>
 19#include <linux/pci.h>
 20#include <linux/io.h>
 21#include <asm/io_trapped.h>
 22#include <asm/page.h>
 23#include <asm/pgalloc.h>
 24#include <asm/addrspace.h>
 25#include <asm/cacheflush.h>
 26#include <asm/tlbflush.h>
 27#include <asm/mmu.h>
 28#include "ioremap.h"
 29
 30/*
 31 * On 32-bit SH, we traditionally have the whole physical address space mapped
 32 * at all times (as MIPS does), so "ioremap()" and "iounmap()" do not need to do
 33 * anything but place the address in the proper segment.  This is true for P1
 34 * and P2 addresses, as well as some P3 ones.  However, most of the P3 addresses
 35 * and newer cores using extended addressing need to map through page tables, so
 36 * the ioremap() implementation becomes a bit more complicated.
 37 */
 38#ifdef CONFIG_29BIT
 39static void __iomem *
 40__ioremap_29bit(phys_addr_t offset, unsigned long size, pgprot_t prot)
 41{
 42	phys_addr_t last_addr = offset + size - 1;
 43
 44	/*
 45	 * For P1 and P2 space this is trivial, as everything is already
 46	 * mapped. Uncached access for P1 addresses are done through P2.
 47	 * In the P3 case or for addresses outside of the 29-bit space,
 48	 * mapping must be done by the PMB or by using page tables.
 49	 */
 50	if (likely(PXSEG(offset) < P3SEG && PXSEG(last_addr) < P3SEG)) {
 51		u64 flags = pgprot_val(prot);
 52
 53		/*
 54		 * Anything using the legacy PTEA space attributes needs
 55		 * to be kicked down to page table mappings.
 56		 */
 57		if (unlikely(flags & _PAGE_PCC_MASK))
 58			return NULL;
 59		if (unlikely(flags & _PAGE_CACHABLE))
 60			return (void __iomem *)P1SEGADDR(offset);
 61
 62		return (void __iomem *)P2SEGADDR(offset);
 63	}
 64
 65	/* P4 above the store queues are always mapped. */
 66	if (unlikely(offset >= P3_ADDR_MAX))
 67		return (void __iomem *)P4SEGADDR(offset);
 68
 69	return NULL;
 70}
 71#else
 72#define __ioremap_29bit(offset, size, prot)		NULL
 73#endif /* CONFIG_29BIT */
 74
 75void __iomem __ref *ioremap_prot(phys_addr_t phys_addr, size_t size,
 76				 pgprot_t pgprot)
 77{
 78	void __iomem *mapped;
 79
 80	mapped = __ioremap_trapped(phys_addr, size);
 81	if (mapped)
 82		return mapped;
 83
 84	mapped = __ioremap_29bit(phys_addr, size, pgprot);
 85	if (mapped)
 86		return mapped;
 87
 88	/*
 89	 * If we can't yet use the regular approach, go the fixmap route.
 90	 */
 91	if (!mem_init_done)
 92		return ioremap_fixed(phys_addr, size, pgprot);
 93
 94	/*
 95	 * First try to remap through the PMB.
 96	 * PMB entries are all pre-faulted.
 97	 */
 98	mapped = pmb_remap_caller(phys_addr, size, pgprot,
 99			__builtin_return_address(0));
100	if (mapped && !IS_ERR(mapped))
101		return mapped;
102
103	return generic_ioremap_prot(phys_addr, size, pgprot);
104}
105EXPORT_SYMBOL(ioremap_prot);
106
107/*
108 * Simple checks for non-translatable mappings.
109 */
110static inline int iomapping_nontranslatable(unsigned long offset)
111{
112#ifdef CONFIG_29BIT
113	/*
114	 * In 29-bit mode this includes the fixed P1/P2 areas, as well as
115	 * parts of P3.
116	 */
117	if (PXSEG(offset) < P3SEG || offset >= P3_ADDR_MAX)
118		return 1;
119#endif
120
121	return 0;
122}
123
124void iounmap(volatile void __iomem *addr)
125{
126	unsigned long vaddr = (unsigned long __force)addr;
127
128	/*
129	 * Nothing to do if there is no translatable mapping.
130	 */
131	if (iomapping_nontranslatable(vaddr))
132		return;
133
134	/*
135	 * There's no VMA if it's from an early fixed mapping.
136	 */
137	if (iounmap_fixed((void __iomem *)addr) == 0)
138		return;
139
140	/*
141	 * If the PMB handled it, there's nothing else to do.
142	 */
143	if (pmb_unmap((void __iomem *)addr) == 0)
144		return;
145
146	generic_iounmap(addr);
147}
148EXPORT_SYMBOL(iounmap);