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
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
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);
