![Benjamin Herrenschmidt](/assets/img/avatar_default.png)
This rewrites pretty much from scratch the handling of MMIO and PIO space allocations on powerpc64. The main goals are: - Get rid of imalloc and use more common code where possible - Simplify the current mess so that PIO space is allocated and mapped in a single place for PCI bridges - Handle allocation constraints of PIO for all bridges including hot plugged ones within the 2GB space reserved for IO ports, so that devices on hotplugged busses will now work with drivers that assume IO ports fit in an int. - Cleanup and separate tracking of the ISA space in the reserved low 64K of IO space. No ISA -> Nothing mapped there. I booted a cell blade with IDE on PIO and MMIO and a dual G5 so far, that's it :-) With this patch, all allocations are done using the code in mm/vmalloc.c, though we use the low level __get_vm_area with explicit start/stop constraints in order to manage separate areas for vmalloc/vmap, ioremap, and PCI IOs. This greatly simplifies a lot of things, as you can see in the diffstat of that patch :-) A new pair of functions pcibios_map/unmap_io_space() now replace all of the previous code that used to manipulate PCI IOs space. The allocation is done at mapping time, which is now called from scan_phb's, just before the devices are probed (instead of after, which is by itself a bug fix). The only other caller is the PCI hotplug code for hot adding PCI-PCI bridges (slots). imalloc is gone, as is the "sub-allocation" thing, but I do beleive that hotplug should still work in the sense that the space allocation is always done by the PHB, but if you unmap a child bus of this PHB (which seems to be possible), then the code should properly tear down all the HPTE mappings for that area of the PHB allocated IO space. I now always reserve the first 64K of IO space for the bridge with the ISA bus on it. I have moved the code for tracking ISA in a separate file which should also make it smarter if we ever are capable of hot unplugging or re-plugging an ISA bridge. This should have a side effect on platforms like powermac where VGA IOs will no longer work. This is done on purpose though as they would have worked semi-randomly before. The idea at this point is to isolate drivers that might need to access those and fix them by providing a proper function to obtain an offset to the legacy IOs of a given bus. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
234 lines
5.6 KiB
C
234 lines
5.6 KiB
C
/*
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* This file contains ioremap and related functions for 64-bit machines.
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*
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* Derived from arch/ppc64/mm/init.c
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Modifications by Paul Mackerras (PowerMac) (paulus@samba.org)
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* and Cort Dougan (PReP) (cort@cs.nmt.edu)
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* Copyright (C) 1996 Paul Mackerras
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* Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
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*
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* Derived from "arch/i386/mm/init.c"
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*
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* Dave Engebretsen <engebret@us.ibm.com>
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* Rework for PPC64 port.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/stddef.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <asm/pgalloc.h>
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#include <asm/page.h>
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#include <asm/prom.h>
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#include <asm/io.h>
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#include <asm/mmu_context.h>
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#include <asm/pgtable.h>
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#include <asm/mmu.h>
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#include <asm/smp.h>
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#include <asm/machdep.h>
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#include <asm/tlb.h>
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#include <asm/processor.h>
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#include <asm/cputable.h>
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#include <asm/sections.h>
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#include <asm/system.h>
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#include <asm/abs_addr.h>
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#include <asm/firmware.h>
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#include "mmu_decl.h"
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unsigned long ioremap_bot = IOREMAP_BASE;
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/*
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* map_io_page currently only called by __ioremap
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* map_io_page adds an entry to the ioremap page table
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* and adds an entry to the HPT, possibly bolting it
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*/
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static int map_io_page(unsigned long ea, unsigned long pa, int flags)
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{
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pgd_t *pgdp;
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pud_t *pudp;
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pmd_t *pmdp;
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pte_t *ptep;
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if (mem_init_done) {
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pgdp = pgd_offset_k(ea);
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pudp = pud_alloc(&init_mm, pgdp, ea);
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if (!pudp)
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return -ENOMEM;
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pmdp = pmd_alloc(&init_mm, pudp, ea);
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if (!pmdp)
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return -ENOMEM;
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ptep = pte_alloc_kernel(pmdp, ea);
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if (!ptep)
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return -ENOMEM;
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set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT,
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__pgprot(flags)));
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} else {
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/*
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* If the mm subsystem is not fully up, we cannot create a
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* linux page table entry for this mapping. Simply bolt an
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* entry in the hardware page table.
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*
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*/
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if (htab_bolt_mapping(ea, (unsigned long)ea + PAGE_SIZE,
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pa, flags, mmu_io_psize)) {
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printk(KERN_ERR "Failed to do bolted mapping IO "
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"memory at %016lx !\n", pa);
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return -ENOMEM;
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}
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}
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return 0;
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}
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/**
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* __ioremap_at - Low level function to establish the page tables
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* for an IO mapping
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*/
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void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
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unsigned long flags)
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{
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unsigned long i;
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if ((flags & _PAGE_PRESENT) == 0)
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flags |= pgprot_val(PAGE_KERNEL);
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WARN_ON(pa & ~PAGE_MASK);
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WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
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WARN_ON(size & ~PAGE_MASK);
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for (i = 0; i < size; i += PAGE_SIZE)
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if (map_io_page((unsigned long)ea+i, pa+i, flags))
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return NULL;
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return (void __iomem *)ea;
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}
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/**
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* __iounmap_from - Low level function to tear down the page tables
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* for an IO mapping. This is used for mappings that
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* are manipulated manually, like partial unmapping of
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* PCI IOs or ISA space.
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*/
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void __iounmap_at(void *ea, unsigned long size)
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{
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WARN_ON(((unsigned long)ea) & ~PAGE_MASK);
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WARN_ON(size & ~PAGE_MASK);
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unmap_kernel_range((unsigned long)ea, size);
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}
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void __iomem * __ioremap(phys_addr_t addr, unsigned long size,
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unsigned long flags)
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{
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phys_addr_t paligned;
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void __iomem *ret;
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/*
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* Choose an address to map it to.
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* Once the imalloc system is running, we use it.
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* Before that, we map using addresses going
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* up from ioremap_bot. imalloc will use
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* the addresses from ioremap_bot through
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* IMALLOC_END
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*
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*/
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paligned = addr & PAGE_MASK;
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size = PAGE_ALIGN(addr + size) - paligned;
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if ((size == 0) || (paligned == 0))
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return NULL;
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if (mem_init_done) {
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struct vm_struct *area;
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area = __get_vm_area(size, VM_IOREMAP,
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ioremap_bot, IOREMAP_END);
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if (area == NULL)
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return NULL;
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ret = __ioremap_at(paligned, area->addr, size, flags);
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if (!ret)
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vunmap(area->addr);
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} else {
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ret = __ioremap_at(paligned, (void *)ioremap_bot, size, flags);
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if (ret)
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ioremap_bot += size;
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}
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if (ret)
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ret += addr & ~PAGE_MASK;
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return ret;
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}
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void __iomem * ioremap(phys_addr_t addr, unsigned long size)
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{
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unsigned long flags = _PAGE_NO_CACHE | _PAGE_GUARDED;
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if (ppc_md.ioremap)
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return ppc_md.ioremap(addr, size, flags);
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return __ioremap(addr, size, flags);
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}
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void __iomem * ioremap_flags(phys_addr_t addr, unsigned long size,
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unsigned long flags)
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{
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if (ppc_md.ioremap)
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return ppc_md.ioremap(addr, size, flags);
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return __ioremap(addr, size, flags);
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}
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/*
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* Unmap an IO region and remove it from imalloc'd list.
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* Access to IO memory should be serialized by driver.
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*/
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void __iounmap(volatile void __iomem *token)
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{
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void *addr;
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if (!mem_init_done)
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return;
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addr = (void *) ((unsigned long __force)
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PCI_FIX_ADDR(token) & PAGE_MASK);
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if ((unsigned long)addr < ioremap_bot) {
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printk(KERN_WARNING "Attempt to iounmap early bolted mapping"
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" at 0x%p\n", addr);
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return;
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}
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vunmap(addr);
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}
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void iounmap(volatile void __iomem *token)
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{
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if (ppc_md.iounmap)
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ppc_md.iounmap(token);
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else
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__iounmap(token);
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}
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EXPORT_SYMBOL(ioremap);
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EXPORT_SYMBOL(ioremap_flags);
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EXPORT_SYMBOL(__ioremap);
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EXPORT_SYMBOL(iounmap);
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EXPORT_SYMBOL(__iounmap);
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