linux/arch/arm/mm/ioremap.c
Russell King 932c42b286 ARM: avoid annoying <4>'s in printk output
Adding KERN_WARNING in the middle of strings now produces those tokens
in the output, rather than accepting the level as was once the case.
Fix this in the one reported case.  There might be more...

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-11-23 22:27:55 +00:00

325 lines
8.5 KiB
C

/*
* linux/arch/arm/mm/ioremap.c
*
* Re-map IO memory to kernel address space so that we can access it.
*
* (C) Copyright 1995 1996 Linus Torvalds
*
* Hacked for ARM by Phil Blundell <philb@gnu.org>
* Hacked to allow all architectures to build, and various cleanups
* by Russell King
*
* This allows a driver to remap an arbitrary region of bus memory into
* virtual space. One should *only* use readl, writel, memcpy_toio and
* so on with such remapped areas.
*
* Because the ARM only has a 32-bit address space we can't address the
* whole of the (physical) PCI space at once. PCI huge-mode addressing
* allows us to circumvent this restriction by splitting PCI space into
* two 2GB chunks and mapping only one at a time into processor memory.
* We use MMU protection domains to trap any attempt to access the bank
* that is not currently mapped. (This isn't fully implemented yet.)
*/
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/io.h>
#include <asm/cputype.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/sizes.h>
#include <asm/mach/map.h>
#include "mm.h"
/*
* Used by ioremap() and iounmap() code to mark (super)section-mapped
* I/O regions in vm_struct->flags field.
*/
#define VM_ARM_SECTION_MAPPING 0x80000000
int ioremap_page(unsigned long virt, unsigned long phys,
const struct mem_type *mtype)
{
return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
__pgprot(mtype->prot_pte));
}
EXPORT_SYMBOL(ioremap_page);
void __check_kvm_seq(struct mm_struct *mm)
{
unsigned int seq;
do {
seq = init_mm.context.kvm_seq;
memcpy(pgd_offset(mm, VMALLOC_START),
pgd_offset_k(VMALLOC_START),
sizeof(pgd_t) * (pgd_index(VMALLOC_END) -
pgd_index(VMALLOC_START)));
mm->context.kvm_seq = seq;
} while (seq != init_mm.context.kvm_seq);
}
#ifndef CONFIG_SMP
/*
* Section support is unsafe on SMP - If you iounmap and ioremap a region,
* the other CPUs will not see this change until their next context switch.
* Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
* which requires the new ioremap'd region to be referenced, the CPU will
* reference the _old_ region.
*
* Note that get_vm_area_caller() allocates a guard 4K page, so we need to
* mask the size back to 1MB aligned or we will overflow in the loop below.
*/
static void unmap_area_sections(unsigned long virt, unsigned long size)
{
unsigned long addr = virt, end = virt + (size & ~(SZ_1M - 1));
pgd_t *pgd;
flush_cache_vunmap(addr, end);
pgd = pgd_offset_k(addr);
do {
pmd_t pmd, *pmdp = pmd_offset(pgd, addr);
pmd = *pmdp;
if (!pmd_none(pmd)) {
/*
* Clear the PMD from the page table, and
* increment the kvm sequence so others
* notice this change.
*
* Note: this is still racy on SMP machines.
*/
pmd_clear(pmdp);
init_mm.context.kvm_seq++;
/*
* Free the page table, if there was one.
*/
if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
}
addr += PGDIR_SIZE;
pgd++;
} while (addr < end);
/*
* Ensure that the active_mm is up to date - we want to
* catch any use-after-iounmap cases.
*/
if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq)
__check_kvm_seq(current->active_mm);
flush_tlb_kernel_range(virt, end);
}
static int
remap_area_sections(unsigned long virt, unsigned long pfn,
size_t size, const struct mem_type *type)
{
unsigned long addr = virt, end = virt + size;
pgd_t *pgd;
/*
* Remove and free any PTE-based mapping, and
* sync the current kernel mapping.
*/
unmap_area_sections(virt, size);
pgd = pgd_offset_k(addr);
do {
pmd_t *pmd = pmd_offset(pgd, addr);
pmd[0] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
pfn += SZ_1M >> PAGE_SHIFT;
pmd[1] = __pmd(__pfn_to_phys(pfn) | type->prot_sect);
pfn += SZ_1M >> PAGE_SHIFT;
flush_pmd_entry(pmd);
addr += PGDIR_SIZE;
pgd++;
} while (addr < end);
return 0;
}
static int
remap_area_supersections(unsigned long virt, unsigned long pfn,
size_t size, const struct mem_type *type)
{
unsigned long addr = virt, end = virt + size;
pgd_t *pgd;
/*
* Remove and free any PTE-based mapping, and
* sync the current kernel mapping.
*/
unmap_area_sections(virt, size);
pgd = pgd_offset_k(virt);
do {
unsigned long super_pmd_val, i;
super_pmd_val = __pfn_to_phys(pfn) | type->prot_sect |
PMD_SECT_SUPER;
super_pmd_val |= ((pfn >> (32 - PAGE_SHIFT)) & 0xf) << 20;
for (i = 0; i < 8; i++) {
pmd_t *pmd = pmd_offset(pgd, addr);
pmd[0] = __pmd(super_pmd_val);
pmd[1] = __pmd(super_pmd_val);
flush_pmd_entry(pmd);
addr += PGDIR_SIZE;
pgd++;
}
pfn += SUPERSECTION_SIZE >> PAGE_SHIFT;
} while (addr < end);
return 0;
}
#endif
void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
unsigned long offset, size_t size, unsigned int mtype, void *caller)
{
const struct mem_type *type;
int err;
unsigned long addr;
struct vm_struct * area;
/*
* High mappings must be supersection aligned
*/
if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SUPERSECTION_MASK))
return NULL;
/*
* Don't allow RAM to be mapped - this causes problems with ARMv6+
*/
if (pfn_valid(pfn)) {
printk(KERN_WARNING "BUG: Your driver calls ioremap() on system memory. This leads\n"
"to architecturally unpredictable behaviour on ARMv6+, and ioremap()\n"
"will fail in the next kernel release. Please fix your driver.\n");
WARN_ON(1);
}
type = get_mem_type(mtype);
if (!type)
return NULL;
/*
* Page align the mapping size, taking account of any offset.
*/
size = PAGE_ALIGN(offset + size);
area = get_vm_area_caller(size, VM_IOREMAP, caller);
if (!area)
return NULL;
addr = (unsigned long)area->addr;
#ifndef CONFIG_SMP
if (DOMAIN_IO == 0 &&
(((cpu_architecture() >= CPU_ARCH_ARMv6) && (get_cr() & CR_XP)) ||
cpu_is_xsc3()) && pfn >= 0x100000 &&
!((__pfn_to_phys(pfn) | size | addr) & ~SUPERSECTION_MASK)) {
area->flags |= VM_ARM_SECTION_MAPPING;
err = remap_area_supersections(addr, pfn, size, type);
} else if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
area->flags |= VM_ARM_SECTION_MAPPING;
err = remap_area_sections(addr, pfn, size, type);
} else
#endif
err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
__pgprot(type->prot_pte));
if (err) {
vunmap((void *)addr);
return NULL;
}
flush_cache_vmap(addr, addr + size);
return (void __iomem *) (offset + addr);
}
void __iomem *__arm_ioremap_caller(unsigned long phys_addr, size_t size,
unsigned int mtype, void *caller)
{
unsigned long last_addr;
unsigned long offset = phys_addr & ~PAGE_MASK;
unsigned long pfn = __phys_to_pfn(phys_addr);
/*
* Don't allow wraparound or zero size
*/
last_addr = phys_addr + size - 1;
if (!size || last_addr < phys_addr)
return NULL;
return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
caller);
}
/*
* Remap an arbitrary physical address space into the kernel virtual
* address space. Needed when the kernel wants to access high addresses
* directly.
*
* NOTE! We need to allow non-page-aligned mappings too: we will obviously
* have to convert them into an offset in a page-aligned mapping, but the
* caller shouldn't need to know that small detail.
*/
void __iomem *
__arm_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
unsigned int mtype)
{
return __arm_ioremap_pfn_caller(pfn, offset, size, mtype,
__builtin_return_address(0));
}
EXPORT_SYMBOL(__arm_ioremap_pfn);
void __iomem *
__arm_ioremap(unsigned long phys_addr, size_t size, unsigned int mtype)
{
return __arm_ioremap_caller(phys_addr, size, mtype,
__builtin_return_address(0));
}
EXPORT_SYMBOL(__arm_ioremap);
void __iounmap(volatile void __iomem *io_addr)
{
void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
#ifndef CONFIG_SMP
struct vm_struct **p, *tmp;
/*
* If this is a section based mapping we need to handle it
* specially as the VM subsystem does not know how to handle
* such a beast. We need the lock here b/c we need to clear
* all the mappings before the area can be reclaimed
* by someone else.
*/
write_lock(&vmlist_lock);
for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) {
if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) {
if (tmp->flags & VM_ARM_SECTION_MAPPING) {
unmap_area_sections((unsigned long)tmp->addr,
tmp->size);
}
break;
}
}
write_unlock(&vmlist_lock);
#endif
vunmap(addr);
}
EXPORT_SYMBOL(__iounmap);