From b50f1704e9c441c58cf6dc05e72953ca30e1d4d2 Mon Sep 17 00:00:00 2001 From: GuanXuetao Date: Sat, 15 Jan 2011 18:16:59 +0800 Subject: unicore32 core architecture: mm related: generic codes This patch includes generic codes for memory management. Signed-off-by: Guan Xuetao Reviewed-by: Arnd Bergmann --- arch/unicore32/mm/ioremap.c | 261 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 261 insertions(+) create mode 100644 arch/unicore32/mm/ioremap.c (limited to 'arch/unicore32/mm/ioremap.c') diff --git a/arch/unicore32/mm/ioremap.c b/arch/unicore32/mm/ioremap.c new file mode 100644 index 000000000000..b7a605597b08 --- /dev/null +++ b/arch/unicore32/mm/ioremap.c @@ -0,0 +1,261 @@ +/* + * linux/arch/unicore32/mm/ioremap.c + * + * Code specific to PKUnity SoC and UniCore ISA + * + * Copyright (C) 2001-2010 GUAN Xue-tao + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * + * Re-map IO memory to kernel address space so that we can access it. + * + * This allows a driver to remap an arbitrary region of bus memory into + * virtual space. One should *only* use readl, writel, memcpy_toio and + * so on with such remapped areas. + * + * Because UniCore only has a 32-bit address space we can't address the + * whole of the (physical) PCI space at once. PCI huge-mode addressing + * allows us to circumvent this restriction by splitting PCI space into + * two 2GB chunks and mapping only one at a time into processor memory. + * We use MMU protection domains to trap any attempt to access the bank + * that is not currently mapped. (This isn't fully implemented yet.) + */ +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +#include +#include "mm.h" + +/* + * Used by ioremap() and iounmap() code to mark (super)section-mapped + * I/O regions in vm_struct->flags field. + */ +#define VM_UNICORE_SECTION_MAPPING 0x80000000 + +int ioremap_page(unsigned long virt, unsigned long phys, + const struct mem_type *mtype) +{ + return ioremap_page_range(virt, virt + PAGE_SIZE, phys, + __pgprot(mtype->prot_pte)); +} +EXPORT_SYMBOL(ioremap_page); + +/* + * Section support is unsafe on SMP - If you iounmap and ioremap a region, + * the other CPUs will not see this change until their next context switch. + * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs + * which requires the new ioremap'd region to be referenced, the CPU will + * reference the _old_ region. + * + * Note that get_vm_area_caller() allocates a guard 4K page, so we need to + * mask the size back to 4MB aligned or we will overflow in the loop below. + */ +static void unmap_area_sections(unsigned long virt, unsigned long size) +{ + unsigned long addr = virt, end = virt + (size & ~(SZ_4M - 1)); + pgd_t *pgd; + + flush_cache_vunmap(addr, end); + pgd = pgd_offset_k(addr); + do { + pmd_t pmd, *pmdp = pmd_offset((pud_t *)pgd, addr); + + pmd = *pmdp; + if (!pmd_none(pmd)) { + /* + * Clear the PMD from the page table, and + * increment the kvm sequence so others + * notice this change. + * + * Note: this is still racy on SMP machines. + */ + pmd_clear(pmdp); + + /* + * Free the page table, if there was one. + */ + if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) + pte_free_kernel(&init_mm, pmd_page_vaddr(pmd)); + } + + addr += PGDIR_SIZE; + pgd++; + } while (addr < end); + + flush_tlb_kernel_range(virt, end); +} + +static int +remap_area_sections(unsigned long virt, unsigned long pfn, + size_t size, const struct mem_type *type) +{ + unsigned long addr = virt, end = virt + size; + pgd_t *pgd; + + /* + * Remove and free any PTE-based mapping, and + * sync the current kernel mapping. + */ + unmap_area_sections(virt, size); + + pgd = pgd_offset_k(addr); + do { + pmd_t *pmd = pmd_offset((pud_t *)pgd, addr); + + set_pmd(pmd, __pmd(__pfn_to_phys(pfn) | type->prot_sect)); + pfn += SZ_4M >> PAGE_SHIFT; + flush_pmd_entry(pmd); + + addr += PGDIR_SIZE; + pgd++; + } while (addr < end); + + return 0; +} + +void __iomem *__uc32_ioremap_pfn_caller(unsigned long pfn, + unsigned long offset, size_t size, unsigned int mtype, void *caller) +{ + const struct mem_type *type; + int err; + unsigned long addr; + struct vm_struct *area; + + /* + * High mappings must be section aligned + */ + if (pfn >= 0x100000 && (__pfn_to_phys(pfn) & ~SECTION_MASK)) + return NULL; + + /* + * Don't allow RAM to be mapped + */ + if (pfn_valid(pfn)) { + printk(KERN_WARNING "BUG: Your driver calls ioremap() on\n" + "system memory. This leads to architecturally\n" + "unpredictable behaviour, and ioremap() will fail in\n" + "the next kernel release. Please fix your driver.\n"); + WARN_ON(1); + } + + type = get_mem_type(mtype); + if (!type) + return NULL; + + /* + * Page align the mapping size, taking account of any offset. + */ + size = PAGE_ALIGN(offset + size); + + area = get_vm_area_caller(size, VM_IOREMAP, caller); + if (!area) + return NULL; + addr = (unsigned long)area->addr; + + if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { + area->flags |= VM_UNICORE_SECTION_MAPPING; + err = remap_area_sections(addr, pfn, size, type); + } else + err = ioremap_page_range(addr, addr + size, __pfn_to_phys(pfn), + __pgprot(type->prot_pte)); + + if (err) { + vunmap((void *)addr); + return NULL; + } + + flush_cache_vmap(addr, addr + size); + return (void __iomem *) (offset + addr); +} + +void __iomem *__uc32_ioremap_caller(unsigned long phys_addr, size_t size, + unsigned int mtype, void *caller) +{ + unsigned long last_addr; + unsigned long offset = phys_addr & ~PAGE_MASK; + unsigned long pfn = __phys_to_pfn(phys_addr); + + /* + * Don't allow wraparound or zero size + */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) + return NULL; + + return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, caller); +} + +/* + * 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 * +__uc32_ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, + unsigned int mtype) +{ + return __uc32_ioremap_pfn_caller(pfn, offset, size, mtype, + __builtin_return_address(0)); +} +EXPORT_SYMBOL(__uc32_ioremap_pfn); + +void __iomem * +__uc32_ioremap(unsigned long phys_addr, size_t size) +{ + return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE, + __builtin_return_address(0)); +} +EXPORT_SYMBOL(__uc32_ioremap); + +void __iomem * +__uc32_ioremap_cached(unsigned long phys_addr, size_t size) +{ + return __uc32_ioremap_caller(phys_addr, size, MT_DEVICE_CACHED, + __builtin_return_address(0)); +} +EXPORT_SYMBOL(__uc32_ioremap_cached); + +void __uc32_iounmap(volatile void __iomem *io_addr) +{ + void *addr = (void *)(PAGE_MASK & (unsigned long)io_addr); + struct vm_struct **p, *tmp; + + /* + * If this is a section based mapping we need to handle it + * specially as the VM subsystem does not know how to handle + * such a beast. We need the lock here b/c we need to clear + * all the mappings before the area can be reclaimed + * by someone else. + */ + write_lock(&vmlist_lock); + for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { + if ((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) { + if (tmp->flags & VM_UNICORE_SECTION_MAPPING) { + unmap_area_sections((unsigned long)tmp->addr, + tmp->size); + } + break; + } + } + write_unlock(&vmlist_lock); + + vunmap(addr); +} +EXPORT_SYMBOL(__uc32_iounmap); -- cgit