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/*
* Copyright © 2008 Ingo Molnar
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <asm/iomap.h>
#include <asm/pat.h>
#include <linux/module.h>
#ifdef CONFIG_X86_PAE
static int
is_io_mapping_possible(resource_size_t base, unsigned long size)
{
return 1;
}
#else
static int
is_io_mapping_possible(resource_size_t base, unsigned long size)
{
/* There is no way to map greater than 1 << 32 address without PAE */
if (base + size > 0x100000000ULL)
return 0;
return 1;
}
#endif
int
reserve_io_memtype_wc(u64 base, unsigned long size, pgprot_t *prot)
{
unsigned long ret_flag;
if (!is_io_mapping_possible(base, size))
goto out_err;
if (!pat_enabled) {
*prot = pgprot_noncached(PAGE_KERNEL);
return 0;
}
if (reserve_memtype(base, base + size, _PAGE_CACHE_WC, &ret_flag))
goto out_err;
if (ret_flag == _PAGE_CACHE_WB)
goto out_free;
if (kernel_map_sync_memtype(base, size, ret_flag))
goto out_free;
*prot = __pgprot(__PAGE_KERNEL | ret_flag);
return 0;
out_free:
free_memtype(base, base + size);
out_err:
return -EINVAL;
}
EXPORT_SYMBOL_GPL(reserve_io_memtype_wc);
void
free_io_memtype(u64 base, unsigned long size)
{
if (pat_enabled)
free_memtype(base, base + size);
}
EXPORT_SYMBOL_GPL(free_io_memtype);
/* Map 'pfn' using fixed map 'type' and protections 'prot'
*/
void *
iomap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot)
{
enum fixed_addresses idx;
unsigned long vaddr;
pagefault_disable();
/*
* For non-PAT systems, promote PAGE_KERNEL_WC to PAGE_KERNEL_UC_MINUS.
* PAGE_KERNEL_WC maps to PWT, which translates to uncached if the
* MTRR is UC or WC. UC_MINUS gets the real intention, of the
* user, which is "WC if the MTRR is WC, UC if you can't do that."
*/
if (!pat_enabled && pgprot_val(prot) == pgprot_val(PAGE_KERNEL_WC))
prot = PAGE_KERNEL_UC_MINUS;
idx = type + KM_TYPE_NR*smp_processor_id();
vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
set_pte(kmap_pte-idx, pfn_pte(pfn, prot));
arch_flush_lazy_mmu_mode();
return (void*) vaddr;
}
EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);
void
iounmap_atomic(void *kvaddr, enum km_type type)
{
unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;
enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id();
/*
* Force other mappings to Oops if they'll try to access this pte
* without first remap it. Keeping stale mappings around is a bad idea
* also, in case the page changes cacheability attributes or becomes
* a protected page in a hypervisor.
*/
if (vaddr == __fix_to_virt(FIX_KMAP_BEGIN+idx))
kpte_clear_flush(kmap_pte-idx, vaddr);
arch_flush_lazy_mmu_mode();
pagefault_enable();
}
EXPORT_SYMBOL_GPL(iounmap_atomic);
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