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