nios2: I/O Mapping

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

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

diff --git a/arch/nios2/include/asm/io.h b/arch/nios2/include/asm/io.h
new file mode 100644 (file)
index 0000000..13dc22b
--- /dev/null
+++ b/arch/nios2/include/asm/io.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2014 Altera Corporation
+ * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
+ * 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.
+ */
+
+#ifndef _ASM_NIOS2_IO_H
+#define _ASM_NIOS2_IO_H
+
+#include <asm/pgtable-bits.h>
+#include <asm-generic/iomap.h>
+
+/* PCI is not supported in nios2, set this to 0. */
+#define IO_SPACE_LIMIT 0
+
+#define readb_relaxed(addr)    readb(addr)
+#define readw_relaxed(addr)    readw(addr)
+#define readl_relaxed(addr)    readl(addr)
+
+#define writeb_relaxed(x, addr)        writeb(x, addr)
+#define writew_relaxed(x, addr)        writew(x, addr)
+#define writel_relaxed(x, addr)        writel(x, addr)
+
+#include <asm-generic/io.h>
+
+extern void __iomem *__ioremap(unsigned long physaddr, unsigned long size,
+                       unsigned long cacheflag);
+extern void __iounmap(void __iomem *addr);
+
+static inline void __iomem *ioremap(unsigned long physaddr, unsigned long size)
+{
+       return __ioremap(physaddr, size, 0);
+}
+
+static inline void __iomem *ioremap_nocache(unsigned long physaddr,
+                                               unsigned long size)
+{
+       return __ioremap(physaddr, size, 0);
+}
+
+static inline void iounmap(void __iomem *addr)
+{
+       __iounmap(addr);
+}
+
+/* Pages to physical address... */
+# define page_to_phys(page)    virt_to_phys(page_to_virt(page))
+# define page_to_bus(page)     page_to_virt(page)
+
+/* Macros used for converting between virtual and physical mappings. */
+# define phys_to_virt(vaddr)   \
+       ((void *)((unsigned long)(vaddr) | CONFIG_NIOS2_KERNEL_REGION_BASE))
+/* Clear top 3 bits */
+# define virt_to_phys(vaddr)   \
+       ((unsigned long)((unsigned long)(vaddr) & ~0xE0000000))
+
+#endif /* _ASM_NIOS2_IO_H */

diff --git a/arch/nios2/mm/ioremap.c b/arch/nios2/mm/ioremap.c
new file mode 100644 (file)
index 0000000..3a28177
--- /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);