131 строка
3.6 KiB
C
131 строка
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* OpenRISC ioremap.c
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*
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* Linux architectural port borrowing liberally from similar works of
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* others. All original copyrights apply as per the original source
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* declaration.
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*
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* Modifications for the OpenRISC architecture:
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* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
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* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
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*/
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#include <linux/vmalloc.h>
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#include <linux/io.h>
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#include <linux/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/fixmap.h>
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#include <asm/bug.h>
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#include <linux/sched.h>
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#include <asm/tlbflush.h>
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extern int mem_init_done;
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static unsigned int fixmaps_used __initdata;
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/*
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* Remap an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access high addresses
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* directly.
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*
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* NOTE! We need to allow non-page-aligned mappings too: we will obviously
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* have to convert them into an offset in a page-aligned mapping, but the
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* caller shouldn't need to know that small detail.
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*/
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void __iomem *__ref ioremap(phys_addr_t addr, unsigned long size)
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{
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phys_addr_t p;
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unsigned long v;
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unsigned long offset, last_addr;
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struct vm_struct *area = NULL;
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/* Don't allow wraparound or zero size */
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last_addr = addr + size - 1;
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if (!size || last_addr < addr)
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return NULL;
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/*
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* Mappings have to be page-aligned
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*/
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offset = addr & ~PAGE_MASK;
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p = addr & PAGE_MASK;
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size = PAGE_ALIGN(last_addr + 1) - p;
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if (likely(mem_init_done)) {
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area = get_vm_area(size, VM_IOREMAP);
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if (!area)
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return NULL;
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v = (unsigned long)area->addr;
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} else {
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if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS)
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return NULL;
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v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used);
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fixmaps_used += (size >> PAGE_SHIFT);
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}
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if (ioremap_page_range(v, v + size, p,
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__pgprot(pgprot_val(PAGE_KERNEL) | _PAGE_CI))) {
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if (likely(mem_init_done))
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vfree(area->addr);
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else
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fixmaps_used -= (size >> PAGE_SHIFT);
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return NULL;
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}
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return (void __iomem *)(offset + (char *)v);
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}
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EXPORT_SYMBOL(ioremap);
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void iounmap(void __iomem *addr)
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{
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/* If the page is from the fixmap pool then we just clear out
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* the fixmap mapping.
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*/
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if (unlikely((unsigned long)addr > FIXADDR_START)) {
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/* This is a bit broken... we don't really know
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* how big the area is so it's difficult to know
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* how many fixed pages to invalidate...
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* just flush tlb and hope for the best...
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* consider this a FIXME
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*
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* Really we should be clearing out one or more page
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* table entries for these virtual addresses so that
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* future references cause a page fault... for now, we
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* rely on two things:
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* i) this code never gets called on known boards
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* ii) invalid accesses to the freed areas aren't made
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*/
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flush_tlb_all();
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return;
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}
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return vfree((void *)(PAGE_MASK & (unsigned long)addr));
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}
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EXPORT_SYMBOL(iounmap);
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/**
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* OK, this one's a bit tricky... ioremap can get called before memory is
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* initialized (early serial console does this) and will want to alloc a page
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* for its mapping. No userspace pages will ever get allocated before memory
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* is initialized so this applies only to kernel pages. In the event that
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* this is called before memory is initialized we allocate the page using
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* the memblock infrastructure.
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*/
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pte_t __ref *pte_alloc_one_kernel(struct mm_struct *mm)
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{
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pte_t *pte;
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if (likely(mem_init_done)) {
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pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
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} else {
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pte = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
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if (!pte)
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panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
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__func__, PAGE_SIZE, PAGE_SIZE);
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}
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return pte;
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}
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