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Diffstat (limited to 'arch/nios2/mm/ioremap.c')
| -rw-r--r-- | arch/nios2/mm/ioremap.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/arch/nios2/mm/ioremap.c b/arch/nios2/mm/ioremap.c new file mode 100644 index 000000000..fe821efb9 --- /dev/null +++ b/arch/nios2/mm/ioremap.c @@ -0,0 +1,188 @@ +/* + * 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 { + p4d_t *p4d; + pud_t *pud; + pmd_t *pmd; + + error = -ENOMEM; + p4d = p4d_alloc(&init_mm, dir, address); + if (!p4d) + break; + pud = pud_alloc(&init_mm, p4d, 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) +{ + 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)) + 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, 0)) { + 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); |