136 lines
2.6 KiB
C
136 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Re-map IO memory to kernel address space so that we can access it.
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*
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* These functions should only be used when it is necessary to map a
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* physical address space into the kernel address space before ioremap()
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* can be used, e.g. early in boot before paging_init().
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*
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* Copyright (C) 2009 Matt Fleming
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*/
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#include <linux/vmalloc.h>
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#include <linux/ioport.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/io.h>
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#include <linux/bootmem.h>
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#include <linux/proc_fs.h>
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#include <asm/fixmap.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/addrspace.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu.h>
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#include <asm/mmu_context.h>
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struct ioremap_map {
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void __iomem *addr;
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unsigned long size;
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unsigned long fixmap_addr;
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};
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static struct ioremap_map ioremap_maps[FIX_N_IOREMAPS];
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void __init ioremap_fixed_init(void)
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{
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struct ioremap_map *map;
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int i;
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for (i = 0; i < FIX_N_IOREMAPS; i++) {
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map = &ioremap_maps[i];
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map->fixmap_addr = __fix_to_virt(FIX_IOREMAP_BEGIN + i);
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}
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}
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void __init __iomem *
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ioremap_fixed(phys_addr_t phys_addr, unsigned long size, pgprot_t prot)
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{
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enum fixed_addresses idx0, idx;
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struct ioremap_map *map;
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unsigned int nrpages;
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unsigned long offset;
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int i, slot;
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/*
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* Mappings have to be page-aligned
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*/
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offset = phys_addr & ~PAGE_MASK;
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phys_addr &= PAGE_MASK;
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size = PAGE_ALIGN(phys_addr + size) - phys_addr;
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slot = -1;
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for (i = 0; i < FIX_N_IOREMAPS; i++) {
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map = &ioremap_maps[i];
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if (!map->addr) {
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map->size = size;
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slot = i;
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break;
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}
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}
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if (slot < 0)
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return NULL;
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/*
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* Mappings have to fit in the FIX_IOREMAP area.
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*/
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nrpages = size >> PAGE_SHIFT;
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if (nrpages > FIX_N_IOREMAPS)
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return NULL;
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/*
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* Ok, go for it..
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*/
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idx0 = FIX_IOREMAP_BEGIN + slot;
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idx = idx0;
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while (nrpages > 0) {
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pgprot_val(prot) |= _PAGE_WIRED;
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__set_fixmap(idx, phys_addr, prot);
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phys_addr += PAGE_SIZE;
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idx++;
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--nrpages;
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}
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map->addr = (void __iomem *)(offset + map->fixmap_addr);
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return map->addr;
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}
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int iounmap_fixed(void __iomem *addr)
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{
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enum fixed_addresses idx;
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struct ioremap_map *map;
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unsigned int nrpages;
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int i, slot;
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slot = -1;
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for (i = 0; i < FIX_N_IOREMAPS; i++) {
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map = &ioremap_maps[i];
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if (map->addr == addr) {
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slot = i;
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break;
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}
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}
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/*
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* If we don't match, it's not for us.
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*/
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if (slot < 0)
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return -EINVAL;
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nrpages = map->size >> PAGE_SHIFT;
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idx = FIX_IOREMAP_BEGIN + slot + nrpages - 1;
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while (nrpages > 0) {
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__clear_fixmap(idx, __pgprot(_PAGE_WIRED));
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--idx;
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--nrpages;
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}
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map->size = 0;
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map->addr = NULL;
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return 0;
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}
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