nios2: I/O Mapping

This patch adds several definitions for I/O accessors and ioremap().

Signed-off-by: Ley Foon Tan <lftan@altera.com>

1 files changed, 187 insertions, 0 deletions

diff --git a/arch/nios2/mm/ioremap.c b/arch/nios2/mm/ioremap.c
new file mode 100644
index 000000000000..3a28177a01eb
--- /dev/null
+++ b/arch/nios2/mm/ioremap.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2009 Wind River Systems Inc
+ *   Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ * Copyright (C) 2004 Microtronix Datacom Ltd.
+ *
+ * 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/export.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/io.h>
+
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+
+static inline void remap_area_pte(pte_t *pte, unsigned long address,
+                                unsigned long size, unsigned long phys_addr,
+                                unsigned long flags)
+{
+        unsigned long end;
+        unsigned long pfn;
+        pgprot_t pgprot = __pgprot(_PAGE_GLOBAL | _PAGE_PRESENT | _PAGE_READ
+                                | _PAGE_WRITE | flags);
+
+        address &= ~PMD_MASK;
+        end = address + size;
+        if (end > PMD_SIZE)
+                end = PMD_SIZE;
+        if (address >= end)
+                BUG();
+        pfn = PFN_DOWN(phys_addr);
+        do {
+                if (!pte_none(*pte)) {
+                        pr_err("remap_area_pte: page already exists\n");
+                        BUG();
+                }
+                set_pte(pte, pfn_pte(pfn, pgprot));
+                address += PAGE_SIZE;
+                pfn++;
+                pte++;
+        } while (address && (address < end));
+}
+
+static inline int remap_area_pmd(pmd_t *pmd, unsigned long address,
+                                unsigned long size, unsigned long phys_addr,
+                                unsigned long flags)
+{
+        unsigned long end;
+
+        address &= ~PGDIR_MASK;
+        end = address + size;
+        if (end > PGDIR_SIZE)
+                end = PGDIR_SIZE;
+        phys_addr -= address;
+        if (address >= end)
+                BUG();
+        do {
+                pte_t *pte = pte_alloc_kernel(pmd, address);
+
+                if (!pte)
+                        return -ENOMEM;
+                remap_area_pte(pte, address, end - address, address + phys_addr,
+                        flags);
+                address = (address + PMD_SIZE) & PMD_MASK;
+                pmd++;
+        } while (address && (address < end));
+        return 0;
+}
+
+static int remap_area_pages(unsigned long address, unsigned long phys_addr,
+                                unsigned long size, unsigned long flags)
+{
+        int error;
+        pgd_t *dir;
+        unsigned long end = address + size;
+
+        phys_addr -= address;
+        dir = pgd_offset(&init_mm, address);
+        flush_cache_all();
+        if (address >= end)
+                BUG();
+        do {
+                pud_t *pud;
+                pmd_t *pmd;
+
+                error = -ENOMEM;
+                pud = pud_alloc(&init_mm, dir, address);
+                if (!pud)
+                        break;
+                pmd = pmd_alloc(&init_mm, pud, address);
+                if (!pmd)
+                        break;
+                if (remap_area_pmd(pmd, address, end - address,
+                        phys_addr + address, flags))
+                        break;
+                error = 0;
+                address = (address + PGDIR_SIZE) & PGDIR_MASK;
+                dir++;
+        } while (address && (address < end));
+        flush_tlb_all();
+        return error;
+}
+
+#define IS_MAPPABLE_UNCACHEABLE(addr) (addr < 0x20000000UL)
+
+/*
+ * Map some physical address range into the kernel address space.
+ */
+void __iomem *__ioremap(unsigned long phys_addr, unsigned long size,
+                        unsigned long cacheflag)
+{
+        struct vm_struct *area;
+        unsigned long offset;
+        unsigned long last_addr;
+        void *addr;
+
+        /* Don't allow wraparound or zero size */
+        last_addr = phys_addr + size - 1;
+
+        if (!size || last_addr < phys_addr)
+                return NULL;
+
+        /* Don't allow anybody to remap normal RAM that we're using */
+        if (phys_addr > PHYS_OFFSET && phys_addr < virt_to_phys(high_memory)) {
+                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;
+        }
+
+        /*
+         * Map uncached objects in the low part of address space to
+         * CONFIG_NIOS2_IO_REGION_BASE
+         */
+        if (IS_MAPPABLE_UNCACHEABLE(phys_addr) &&
+            IS_MAPPABLE_UNCACHEABLE(last_addr) &&
+            !(cacheflag & _PAGE_CACHED))
+                return (void __iomem *)(CONFIG_NIOS2_IO_REGION_BASE + phys_addr);
+
+        /* 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);
+        if (!area)
+                return NULL;
+        addr = area->addr;
+        if (remap_area_pages((unsigned long) addr, phys_addr, size,
+                cacheflag)) {
+                vunmap(addr);
+                return NULL;
+        }
+        return (void __iomem *) (offset + (char *)addr);
+}
+EXPORT_SYMBOL(__ioremap);
+
+/*
+ * __iounmap unmaps nearly everything, so be careful
+ * it doesn't free currently pointer/page tables anymore but it
+ * wasn't used anyway and might be added later.
+ */
+void __iounmap(void __iomem *addr)
+{
+        struct vm_struct *p;
+
+        if ((unsigned long) addr > CONFIG_NIOS2_IO_REGION_BASE)
+                return;
+
+        p = remove_vm_area((void *) (PAGE_MASK & (unsigned long __force) addr));
+        if (!p)
+                pr_err("iounmap: bad address %p\n", addr);
+        kfree(p);
+}
+EXPORT_SYMBOL(__iounmap);