2011-01-15 11:16:59 +01:00
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/*
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* linux/arch/unicore32/mm/ioremap.c
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*
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* Code specific to PKUnity SoC and UniCore ISA
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*
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* Copyright (C) 2001-2010 GUAN Xue-tao
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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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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* This allows a driver to remap an arbitrary region of bus memory into
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* virtual space. One should *only* use readl, writel, memcpy_toio and
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* so on with such remapped areas.
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*
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* Because UniCore only has a 32-bit address space we can't address the
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* whole of the (physical) PCI space at once. PCI huge-mode addressing
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* allows us to circumvent this restriction by splitting PCI space into
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* two 2GB chunks and mapping only one at a time into processor memory.
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* We use MMU protection domains to trap any attempt to access the bank
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* that is not currently mapped. (This isn't fully implemented yet.)
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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#include <linux/io.h>
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#include <asm/cputype.h>
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#include <asm/cacheflush.h>
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#include <asm/mmu_context.h>
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#include <asm/pgalloc.h>
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#include <asm/tlbflush.h>
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#include <asm/sizes.h>
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#include <mach/map.h>
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#include "mm.h"
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/*
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* Used by ioremap() and iounmap() code to mark (super)section-mapped
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* I/O regions in vm_struct->flags field.
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*/
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#define VM_UNICORE_SECTION_MAPPING 0x80000000
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int ioremap_page(unsigned long virt, unsigned long phys,
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const struct mem_type *mtype)
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{
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return ioremap_page_range(virt, virt + PAGE_SIZE, phys,
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__pgprot(mtype->prot_pte));
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}
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EXPORT_SYMBOL(ioremap_page);
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/*
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* Section support is unsafe on SMP - If you iounmap and ioremap a region,
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* the other CPUs will not see this change until their next context switch.
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* Meanwhile, (eg) if an interrupt comes in on one of those other CPUs
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* which requires the new ioremap'd region to be referenced, the CPU will
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* reference the _old_ region.
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*
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* Note that get_vm_area_caller() allocates a guard 4K page, so we need to
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* mask the size back to 4MB aligned or we will overflow in the loop below.
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*/
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static void unmap_area_sections(unsigned long virt, unsigned long size)
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{
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unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1));
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pgd_t *pgd;
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flush_cache_vunmap(addr, end);
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pgd = pgd_offset_k(addr);
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do {
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pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr);
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pmd = *pmdp;
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if (!pmd_none(pmd)) {
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/*
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* Clear the PMD from the page table, and
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* increment the kvm sequence so others
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* notice this change.
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*
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* Note: this is still racy on SMP machines.
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*/
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pmd_clear(pmdp);
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/*
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* Free the page table, if there was one.
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*/
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if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE)
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pte_free_kernel(&init_mm, pmd_page_vaddr(pmd));
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}
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addr += PGDIR_SIZE;
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pgd++;
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} while (addr < end);
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flush_tlb_kernel_range(virt, end);
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}
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static int
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remap_area_sections(unsigned long virt, unsigned long pfn,
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size_t size, const struct mem_type *type)
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{
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unsigned long addr = virt, end = virt + size;
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pgd_t *pgd;
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/*
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* Remove and free any PTE-based mapping, and
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* sync the current kernel mapping.
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*/
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unmap_area_sections(virt, size);
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pgd = pgd_offset_k(addr);
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do {
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pmd_t *pmd = pmd_offset((pud_t *)pgd, addr);
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set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect));
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pfn += SZ_4M >> PAGE_SHIFT;
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flush_pmd_entry(pmd);
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addr += PGDIR_SIZE;
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pgd++;
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} while (addr < end);
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return 0;
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}
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void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn,
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unsigned long offset, size_t size, unsigned int mtype, void *caller)
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{
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const struct mem_type *type;
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int err;
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unsigned long addr;
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struct vm_struct *area;
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/*
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* High mappings must be section aligned
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*/
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if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK))
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return NULL;
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/*
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* Don't allow RAM to be mapped
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*/
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if (pfn_valid(pfn)) {
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printk(KERN_WARNING "BUG: Your driver calls ioremap() on\n"
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"system memory. This leads to architecturally\n"
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"unpredictable behaviour, and ioremap() will fail in\n"
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"the next kernel release. Please fix your driver.\n");
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WARN_ON(1);
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}
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type = get_mem_type(mtype);
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if (!type)
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return NULL;
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/*
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* Page align the mapping size, taking account of any offset.
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*/
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size = PAGE_ALIGN(offset + size);
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area = get_vm_area_caller(size, VM_IOREMAP, caller);
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if (!area)
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return NULL;
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addr = (unsigned long)area->addr;
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if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) {
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area->flags |= VM_UNICORE_SECTION_MAPPING;
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err = remap_area_sections(addr, pfn, size, type);
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} else
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err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn),
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__pgprot(type->prot_pte));
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if (err) {
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vunmap((void *)addr);
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return NULL;
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}
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flush_cache_vmap(addr, addr + size);
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return (void __iomem *) (offset + addr);
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}
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void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size,
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unsigned int mtype, void *caller)
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{
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unsigned long last_addr;
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unsigned long offset = phys_addr & ~PAGE_MASK;
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unsigned long pfn = __phys_to_pfn(phys_addr);
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/*
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* Don't allow wraparound or zero size
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*/
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last_addr = phys_addr + size - 1;
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if (!size || last_addr < phys_addr)
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return NULL;
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return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller);
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}
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/*
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* Remap an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access high addresses
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* directly.
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*
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* NOTE! We need to allow non-page-aligned mappings too: we will obviously
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* have to convert them into an offset in a page-aligned mapping, but the
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* caller shouldn't need to know that small detail.
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*/
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void __iomem *
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__uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size,
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unsigned int mtype)
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{
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return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype,
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__builtin_return_address(0));
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}
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EXPORT_SYMBOL(__uc32_ioremap_pfn);
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void __iomem *
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__uc32_ioremap(unsigned long phys_addr, size_t size)
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{
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return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE,
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__builtin_return_address(0));
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}
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EXPORT_SYMBOL(__uc32_ioremap);
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void __iomem *
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__uc32_ioremap_cached(unsigned long phys_addr, size_t size)
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{
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return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE_CACHED,
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__builtin_return_address(0));
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}
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EXPORT_SYMBOL(__uc32_ioremap_cached);
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void __uc32_iounmap(volatile void __iomem *io_addr)
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{
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void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr);
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2013-04-30 00:07:27 +02:00
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struct vm_struct *vm;
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2011-01-15 11:16:59 +01:00
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/*
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* If this is a section based mapping we need to handle it
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* specially as the VM subsystem does not know how to handle
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* such a beast. We need the lock here b/c we need to clear
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* all the mappings before the area can be reclaimed
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* by someone else.
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*/
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2013-04-30 00:07:27 +02:00
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vm = find_vm_area(addr);
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if (vm && (vm->flags & VM_IOREMAP) &&
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(vm->flags & VM_UNICORE_SECTION_MAPPING))
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unmap_area_sections((unsigned long)vm->addr, vm->size);
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2011-01-15 11:16:59 +01:00
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vunmap(addr);
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}
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EXPORT_SYMBOL(__uc32_iounmap);
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