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-rw-r--r--arch/i386/mm/ioremap.c320
1 files changed, 320 insertions, 0 deletions
diff --git a/arch/i386/mm/ioremap.c b/arch/i386/mm/ioremap.c
new file mode 100644
index 00000000000..db06f739991
--- /dev/null
+++ b/arch/i386/mm/ioremap.c
@@ -0,0 +1,320 @@
+/*
+ * arch/i386/mm/ioremap.c
+ *
+ * Re-map IO memory to kernel address space so that we can access it.
+ * This is needed for high PCI addresses that aren't mapped in the
+ * 640k-1MB IO memory area on PC's
+ *
+ * (C) Copyright 1995 1996 Linus Torvalds
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <asm/io.h>
+#include <asm/fixmap.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <asm/pgtable.h>
+
+#define ISA_START_ADDRESS 0xa0000
+#define ISA_END_ADDRESS 0x100000
+
+static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
+ unsigned long end, unsigned long phys_addr, unsigned long flags)
+{
+ pte_t *pte;
+ unsigned long pfn;
+
+ pfn = phys_addr >> PAGE_SHIFT;
+ pte = pte_alloc_kernel(&init_mm, pmd, addr);
+ if (!pte)
+ return -ENOMEM;
+ do {
+ BUG_ON(!pte_none(*pte));
+ set_pte(pte, pfn_pte(pfn, __pgprot(_PAGE_PRESENT | _PAGE_RW |
+ _PAGE_DIRTY | _PAGE_ACCESSED | flags)));
+ pfn++;
+ } while (pte++, addr += PAGE_SIZE, addr != end);
+ return 0;
+}
+
+static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
+ unsigned long end, unsigned long phys_addr, unsigned long flags)
+{
+ pmd_t *pmd;
+ unsigned long next;
+
+ phys_addr -= addr;
+ pmd = pmd_alloc(&init_mm, pud, addr);
+ if (!pmd)
+ return -ENOMEM;
+ do {
+ next = pmd_addr_end(addr, end);
+ if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, flags))
+ return -ENOMEM;
+ } while (pmd++, addr = next, addr != end);
+ return 0;
+}
+
+static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
+ unsigned long end, unsigned long phys_addr, unsigned long flags)
+{
+ pud_t *pud;
+ unsigned long next;
+
+ phys_addr -= addr;
+ pud = pud_alloc(&init_mm, pgd, addr);
+ if (!pud)
+ return -ENOMEM;
+ do {
+ next = pud_addr_end(addr, end);
+ if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, flags))
+ return -ENOMEM;
+ } while (pud++, addr = next, addr != end);
+ return 0;
+}
+
+static int ioremap_page_range(unsigned long addr,
+ unsigned long end, unsigned long phys_addr, unsigned long flags)
+{
+ pgd_t *pgd;
+ unsigned long next;
+ int err;
+
+ BUG_ON(addr >= end);
+ flush_cache_all();
+ phys_addr -= addr;
+ pgd = pgd_offset_k(addr);
+ spin_lock(&init_mm.page_table_lock);
+ do {
+ next = pgd_addr_end(addr, end);
+ err = ioremap_pud_range(pgd, addr, next, phys_addr+addr, flags);
+ if (err)
+ break;
+ } while (pgd++, addr = next, addr != end);
+ spin_unlock(&init_mm.page_table_lock);
+ flush_tlb_all();
+ return err;
+}
+
+/*
+ * Generic mapping function (not visible outside):
+ */
+
+/*
+ * 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 * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags)
+{
+ void __iomem * addr;
+ struct vm_struct * area;
+ unsigned long offset, last_addr;
+
+ /* Don't allow wraparound or zero size */
+ last_addr = phys_addr + size - 1;
+ if (!size || last_addr < phys_addr)
+ return NULL;
+
+ /*
+ * Don't remap the low PCI/ISA area, it's always mapped..
+ */
+ if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
+ return (void __iomem *) phys_to_virt(phys_addr);
+
+ /*
+ * Don't allow anybody to remap normal RAM that we're using..
+ */
+ if (phys_addr <= virt_to_phys(high_memory - 1)) {
+ char *t_addr, *t_end;
+ struct page *page;
+
+ t_addr = __va(phys_addr);
+ t_end = t_addr + (size - 1);
+
+ for(page = virt_to_page(t_addr); page <= virt_to_page(t_end); page++)
+ if(!PageReserved(page))
+ return NULL;
+ }
+
+ /*
+ * Mappings have to be page-aligned
+ */
+ offset = phys_addr & ~PAGE_MASK;
+ phys_addr &= PAGE_MASK;
+ size = PAGE_ALIGN(last_addr+1) - phys_addr;
+
+ /*
+ * Ok, go for it..
+ */
+ area = get_vm_area(size, VM_IOREMAP | (flags << 20));
+ if (!area)
+ return NULL;
+ area->phys_addr = phys_addr;
+ addr = (void __iomem *) area->addr;
+ if (ioremap_page_range((unsigned long) addr,
+ (unsigned long) addr + size, phys_addr, flags)) {
+ vunmap((void __force *) addr);
+ return NULL;
+ }
+ return (void __iomem *) (offset + (char __iomem *)addr);
+}
+
+
+/**
+ * ioremap_nocache - map bus memory into CPU space
+ * @offset: bus address of the memory
+ * @size: size of the resource to map
+ *
+ * ioremap_nocache performs a platform specific sequence of operations to
+ * make bus memory CPU accessible via the readb/readw/readl/writeb/
+ * writew/writel functions and the other mmio helpers. The returned
+ * address is not guaranteed to be usable directly as a virtual
+ * address.
+ *
+ * This version of ioremap ensures that the memory is marked uncachable
+ * on the CPU as well as honouring existing caching rules from things like
+ * the PCI bus. Note that there are other caches and buffers on many
+ * busses. In particular driver authors should read up on PCI writes
+ *
+ * It's useful if some control registers are in such an area and
+ * write combining or read caching is not desirable:
+ *
+ * Must be freed with iounmap.
+ */
+
+void __iomem *ioremap_nocache (unsigned long phys_addr, unsigned long size)
+{
+ unsigned long last_addr;
+ void __iomem *p = __ioremap(phys_addr, size, _PAGE_PCD);
+ if (!p)
+ return p;
+
+ /* Guaranteed to be > phys_addr, as per __ioremap() */
+ last_addr = phys_addr + size - 1;
+
+ if (last_addr < virt_to_phys(high_memory) - 1) {
+ struct page *ppage = virt_to_page(__va(phys_addr));
+ unsigned long npages;
+
+ phys_addr &= PAGE_MASK;
+
+ /* This might overflow and become zero.. */
+ last_addr = PAGE_ALIGN(last_addr);
+
+ /* .. but that's ok, because modulo-2**n arithmetic will make
+ * the page-aligned "last - first" come out right.
+ */
+ npages = (last_addr - phys_addr) >> PAGE_SHIFT;
+
+ if (change_page_attr(ppage, npages, PAGE_KERNEL_NOCACHE) < 0) {
+ iounmap(p);
+ p = NULL;
+ }
+ global_flush_tlb();
+ }
+
+ return p;
+}
+
+void iounmap(volatile void __iomem *addr)
+{
+ struct vm_struct *p;
+ if ((void __force *) addr <= high_memory)
+ return;
+
+ /*
+ * __ioremap special-cases the PCI/ISA range by not instantiating a
+ * vm_area and by simply returning an address into the kernel mapping
+ * of ISA space. So handle that here.
+ */
+ if (addr >= phys_to_virt(ISA_START_ADDRESS) &&
+ addr < phys_to_virt(ISA_END_ADDRESS))
+ return;
+
+ p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
+ if (!p) {
+ printk("__iounmap: bad address %p\n", addr);
+ return;
+ }
+
+ if ((p->flags >> 20) && p->phys_addr < virt_to_phys(high_memory) - 1) {
+ /* p->size includes the guard page, but cpa doesn't like that */
+ change_page_attr(virt_to_page(__va(p->phys_addr)),
+ p->size >> PAGE_SHIFT,
+ PAGE_KERNEL);
+ global_flush_tlb();
+ }
+ kfree(p);
+}
+
+void __init *bt_ioremap(unsigned long phys_addr, unsigned long size)
+{
+ unsigned long offset, last_addr;
+ unsigned int nrpages;
+ enum fixed_addresses idx;
+
+ /* Don't allow wraparound or zero size */
+ last_addr = phys_addr + size - 1;
+ if (!size || last_addr < phys_addr)
+ return NULL;
+
+ /*
+ * Don't remap the low PCI/ISA area, it's always mapped..
+ */
+ if (phys_addr >= ISA_START_ADDRESS && last_addr < ISA_END_ADDRESS)
+ return phys_to_virt(phys_addr);
+
+ /*
+ * Mappings have to be page-aligned
+ */
+ offset = phys_addr & ~PAGE_MASK;
+ phys_addr &= PAGE_MASK;
+ size = PAGE_ALIGN(last_addr) - phys_addr;
+
+ /*
+ * Mappings have to fit in the FIX_BTMAP area.
+ */
+ nrpages = size >> PAGE_SHIFT;
+ if (nrpages > NR_FIX_BTMAPS)
+ return NULL;
+
+ /*
+ * Ok, go for it..
+ */
+ idx = FIX_BTMAP_BEGIN;
+ while (nrpages > 0) {
+ set_fixmap(idx, phys_addr);
+ phys_addr += PAGE_SIZE;
+ --idx;
+ --nrpages;
+ }
+ return (void*) (offset + fix_to_virt(FIX_BTMAP_BEGIN));
+}
+
+void __init bt_iounmap(void *addr, unsigned long size)
+{
+ unsigned long virt_addr;
+ unsigned long offset;
+ unsigned int nrpages;
+ enum fixed_addresses idx;
+
+ virt_addr = (unsigned long)addr;
+ if (virt_addr < fix_to_virt(FIX_BTMAP_BEGIN))
+ return;
+ offset = virt_addr & ~PAGE_MASK;
+ nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
+
+ idx = FIX_BTMAP_BEGIN;
+ while (nrpages > 0) {
+ clear_fixmap(idx);
+ --idx;
+ --nrpages;
+ }
+}