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