/*
* This file contains the routines setting up the linux page tables.
*
* Copyright (C) 2008 Michal Simek
* Copyright (C) 2008 PetaLogix
*
* Copyright (C) 2007 Xilinx, Inc. All rights reserved.
*
* Derived from arch/ppc/mm/pgtable.c:
* -- paulus
*
* Derived from arch/ppc/mm/init.c:
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
* and Cort Dougan (PReP) (cort@cs.nmt.edu)
* Copyright (C) 1996 Paul Mackerras
* Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
*
* Derived from "arch/i386/mm/init.c"
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file COPYING in the main directory of this
* archive for more details.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <linux/init.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <linux/io.h>
#include <asm/mmu.h>
#include <asm/sections.h>
#define flush_HPTE(X, va, pg) _tlbie(va)
unsigned long ioremap_base;
unsigned long ioremap_bot;
/* The maximum lowmem defaults to 768Mb, but this can be configured to
* another value.
*/
#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
#ifndef CONFIG_SMP
struct pgtable_cache_struct quicklists;
#endif
static void __iomem *__ioremap(phys_addr_t addr, unsigned long size,
unsigned long flags)
{
unsigned long v, i;
phys_addr_t p;
int err;
/*
* Choose an address to map it to.
* Once the vmalloc system is running, we use it.
* Before then, we use space going down from ioremap_base
* (ioremap_bot records where we're up to).
*/
p = addr & PAGE_MASK;
size = PAGE_ALIGN(addr + size) - p;
/*
* Don't allow anybody to remap normal RAM that we're using.
* mem_init() sets high_memory so only do the check after that.
*
* However, allow remap of rootfs: TBD
*/
if (mem_init_done &&
p >= memory_start && p < virt_to_phys(high_memory) &&
!(p >= virt_to_phys((unsigned long)&__bss_stop) &&
p < virt_to_phys((unsigned long)__bss_stop))) {
printk(KERN_WARNING "__ioremap(): phys addr "PTE_FMT
" is RAM lr %p\n", (unsigned long)p,
__builtin_return_address(0));
return NULL;
}
if (size == 0)
return NULL;
/*
* Is it already mapped? If the whole area is mapped then we're
* done, otherwise remap it since we want to keep the virt addrs for
* each request contiguous.
*
* We make the assumption here that if the bottom and top
* of the range we want are mapped then it's mapped to the
* same virt address (and this is contiguous).
* -- Cort
*/
if (mem_init_done) {
struct vm_struct *area;
area = get_vm_area(size, VM_IOREMAP);
if (area == NULL)
return NULL;
v = (unsigned long) area->addr;
} else {
v = (ioremap_bot -= size);
}
if ((flags & _PAGE_PRESENT) == 0)
flags |= _PAGE_KERNEL;
if (flags & _PAGE_NO_CACHE)
flags |= _PAGE_GUARDED;
err = 0;
for (i = 0; i < size && err == 0; i += PAGE_SIZE)
err = map_page(v + i, p + i, flags);
if (err) {
if (mem_init_done)
vfree((void *)v);
return NULL;
}
return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
}
void __iomem *ioremap(phys_addr_t addr, unsigned long size)
{
return __ioremap(addr, size, _PAGE_NO_CACHE);
}
EXPORT_SYMBOL(ioremap);
void iounmap(void *addr)
{
if (addr > high_memory && (unsigned long) addr < ioremap_bot)
vfree((void *) (PAGE_MASK & (unsigned long) addr));
}
EXPORT_SYMBOL(iounmap);
int map_page(unsigned long va, phys_addr_t pa, int flags)
{
pmd_t *pd;
pte_t *pg;
int err = -ENOMEM;
/* Use upper 10 bits of VA to index the first level map */
pd = pmd_offset(pgd_offset_k(va), va);
/* Use middle 10 bits of VA to index the second-level map */
pg = pte_alloc_kernel(pd, va); /* from powerpc - pgtable.c */
/* pg = pte_alloc_kernel(&init_mm, pd, va); */
if (pg != NULL) {
err = 0;
set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT,
__pgprot(flags)));
if (unlikely(mem_init_done))
flush_HPTE(0, va, pmd_val(*pd));
/* flush_HPTE(0, va, pg); */
}
return err;
}
void __init adjust_total_lowmem(void)
{
/* TBD */
#if 0
unsigned long max_low_mem = MAX_LOW_MEM;
if (total_lowmem > max_low_mem) {
total_lowmem = max_low_mem;
#ifndef CONFIG_HIGHMEM
printk(KERN_INFO "Warning, memory limited to %ld Mb, use "
"CONFIG_HIGHMEM to reach %ld Mb\n",
max_low_mem >> 20, total_memory >> 20);
total_memory = total_lowmem;
#endif /* CONFIG_HIGHMEM */
}
#endif
}
/*
* Map in all of physical memory starting at CONFIG_KERNEL_START.
*/
void __init mapin_ram(void)
{
unsigned long v, p, s, f;
v = CONFIG_KERNEL_START;
p = memory_start;
for (s = 0; s < memory_size; s += PAGE_SIZE) {
f = _PAGE_PRESENT | _PAGE_ACCESSED |
_PAGE_SHARED | _PAGE_HWEXEC;
if ((char *) v < _stext || (char *) v >= _etext)
f |= _PAGE_WRENABLE;
else
/* On the MicroBlaze, no user access
forces R/W kernel access */
f |= _PAGE_USER;
map_page(v, p, f);
v += PAGE_SIZE;
p += PAGE_SIZE;
}
}
/* is x a power of 2? */
#define is_power_of_2(x) ((x) != 0 && (((x) & ((x) - 1)) == 0))
/*
* Set up a mapping for a block of I/O.
* virt, phys, size must all be page-aligned.
* This should only be called before ioremap is called.
*/
void __init io_block_mapping(unsigned long virt, phys_addr_t phys,
unsigned int size, int flags)
{
int i;
if (virt > CONFIG_KERNEL_START && virt < ioremap_bot)
ioremap_bot = ioremap_base = virt;
/* Put it in the page tables. */
for (i = 0; i < size; i += PAGE_SIZE)
map_page(virt + i, phys + i, flags);
}
/* Scan the real Linux page tables and return a PTE pointer for
* a virtual address in a context.
* Returns true (1) if PTE was found, zero otherwise. The pointer to
* the PTE pointer is unmodified if PTE is not found.
*/
static int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep)
{
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
int retval = 0;
pgd = pgd_offset(mm, addr & PAGE_MASK);
if (pgd) {
pmd = pmd_offset(pgd, addr & PAGE_MASK);
if (pmd_present(*pmd)) {
pte = pte_offset_kernel(pmd, addr & PAGE_MASK);
if (pte) {
retval = 1;
*ptep = pte;
}
}
}
return retval;
}
/* Find physical address for this virtual address. Normally used by
* I/O functions, but anyone can call it.
*/
unsigned long iopa(unsigned long addr)
{
unsigned long pa;
pte_t *pte;
struct mm_struct *mm;
/* Allow mapping of user addresses (within the thread)
* for DMA if necessary.
*/
if (addr < TASK_SIZE)
mm = current->mm;
else
mm = &init_mm;
pa = 0;
if (get_pteptr(mm, addr, &pte))
pa = (pte_val(*pte) & PAGE_MASK) | (addr & ~PAGE_MASK);
return pa;
}
