iomap_32.c 3.4 KB
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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>
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#include <asm/pat.h>
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#include <linux/module.h>
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#include <linux/highmem.h>
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static int is_io_mapping_possible(resource_size_t base, unsigned long size)
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{
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#if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT)
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	/* There is no way to map greater than 1 << 32 address without PAE */
	if (base + size > 0x100000000ULL)
		return 0;
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#endif
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	return 1;
}
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int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot)
{
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	enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC;
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	int ret;

	if (!is_io_mapping_possible(base, size))
		return -EINVAL;

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	ret = io_reserve_memtype(base, base + size, &pcm);
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	if (ret)
		return ret;

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	*prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm));
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	return 0;
}
EXPORT_SYMBOL_GPL(iomap_create_wc);

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void iomap_free(resource_size_t base, unsigned long size)
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{
	io_free_memtype(base, base + size);
}
EXPORT_SYMBOL_GPL(iomap_free);
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void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
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{
	unsigned long vaddr;
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	int idx, type;
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	pagefault_disable();

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	type = kmap_atomic_idx_push();
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	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;
}

/*
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 * Map 'pfn' using protections 'prot'
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 */
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void __iomem *
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iomap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
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{
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	/*
	 * 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."
	 */
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	if (!pat_enabled() && pgprot_val(prot) ==
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	    (__PAGE_KERNEL | cachemode2protval(_PAGE_CACHE_MODE_WC)))
		prot = __pgprot(__PAGE_KERNEL |
				cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS));
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	return (void __force __iomem *) kmap_atomic_prot_pfn(pfn, prot);
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}
EXPORT_SYMBOL_GPL(iomap_atomic_prot_pfn);

void
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iounmap_atomic(void __iomem *kvaddr)
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{
	unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK;

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	if (vaddr >= __fix_to_virt(FIX_KMAP_END) &&
	    vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) {
		int idx, type;

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		type = kmap_atomic_idx();
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		idx = type + KM_TYPE_NR * smp_processor_id();

#ifdef CONFIG_DEBUG_HIGHMEM
		WARN_ON_ONCE(vaddr != __fix_to_virt(FIX_KMAP_BEGIN + idx));
#endif
		/*
		 * 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.
		 */
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		kpte_clear_flush(kmap_pte-idx, vaddr);
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		kmap_atomic_idx_pop();
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	}
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	pagefault_enable();
}
EXPORT_SYMBOL_GPL(iounmap_atomic);