252 lines
6.3 KiB
C
252 lines
6.3 KiB
C
/*
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* Microblaze support for cache consistent memory.
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* Copyright (C) 2010 Michal Simek <monstr@monstr.eu>
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* Copyright (C) 2010 PetaLogix
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* Copyright (C) 2005 John Williams <jwilliams@itee.uq.edu.au>
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*
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* Based on PowerPC version derived from arch/arm/mm/consistent.c
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* Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
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* Copyright (C) 2000 Russell King
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/export.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/ptrace.h>
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#include <linux/mman.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/stddef.h>
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#include <linux/vmalloc.h>
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#include <linux/init.h>
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#include <linux/delay.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
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#include <linux/pci.h>
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#include <linux/interrupt.h>
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#include <linux/gfp.h>
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#include <asm/pgalloc.h>
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#include <linux/io.h>
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#include <linux/hardirq.h>
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#include <linux/mmu_context.h>
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#include <asm/mmu.h>
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#include <linux/uaccess.h>
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#include <asm/pgtable.h>
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#include <asm/cpuinfo.h>
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#include <asm/tlbflush.h>
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#ifndef CONFIG_MMU
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/* I have to use dcache values because I can't relate on ram size */
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# define UNCACHED_SHADOW_MASK (cpuinfo.dcache_high - cpuinfo.dcache_base + 1)
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#endif
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/*
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* Consistent memory allocators. Used for DMA devices that want to
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* share uncached memory with the processor core.
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* My crufty no-MMU approach is simple. In the HW platform we can optionally
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* mirror the DDR up above the processor cacheable region. So, memory accessed
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* in this mirror region will not be cached. It's alloced from the same
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* pool as normal memory, but the handle we return is shifted up into the
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* uncached region. This will no doubt cause big problems if memory allocated
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* here is not also freed properly. -- JW
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*/
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void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
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{
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unsigned long order, vaddr;
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void *ret;
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unsigned int i, err = 0;
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struct page *page, *end;
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#ifdef CONFIG_MMU
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phys_addr_t pa;
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struct vm_struct *area;
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unsigned long va;
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#endif
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if (in_interrupt())
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BUG();
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/* Only allocate page size areas. */
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size = PAGE_ALIGN(size);
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order = get_order(size);
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vaddr = __get_free_pages(gfp, order);
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if (!vaddr)
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return NULL;
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/*
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* we need to ensure that there are no cachelines in use,
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* or worse dirty in this area.
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*/
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flush_dcache_range(virt_to_phys((void *)vaddr),
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virt_to_phys((void *)vaddr) + size);
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#ifndef CONFIG_MMU
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ret = (void *)vaddr;
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/*
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* Here's the magic! Note if the uncached shadow is not implemented,
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* it's up to the calling code to also test that condition and make
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* other arranegments, such as manually flushing the cache and so on.
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*/
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# ifdef CONFIG_XILINX_UNCACHED_SHADOW
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ret = (void *)((unsigned) ret | UNCACHED_SHADOW_MASK);
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# endif
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if ((unsigned int)ret > cpuinfo.dcache_base &&
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(unsigned int)ret < cpuinfo.dcache_high)
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pr_warn("ERROR: Your cache coherent area is CACHED!!!\n");
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/* dma_handle is same as physical (shadowed) address */
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*dma_handle = (dma_addr_t)ret;
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#else
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/* Allocate some common virtual space to map the new pages. */
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area = get_vm_area(size, VM_ALLOC);
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if (!area) {
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free_pages(vaddr, order);
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return NULL;
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}
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va = (unsigned long) area->addr;
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ret = (void *)va;
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/* This gives us the real physical address of the first page. */
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*dma_handle = pa = virt_to_bus((void *)vaddr);
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#endif
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/*
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* free wasted pages. We skip the first page since we know
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* that it will have count = 1 and won't require freeing.
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* We also mark the pages in use as reserved so that
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* remap_page_range works.
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*/
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page = virt_to_page(vaddr);
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end = page + (1 << order);
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split_page(page, order);
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for (i = 0; i < size && err == 0; i += PAGE_SIZE) {
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#ifdef CONFIG_MMU
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/* MS: This is the whole magic - use cache inhibit pages */
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err = map_page(va + i, pa + i, _PAGE_KERNEL | _PAGE_NO_CACHE);
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#endif
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SetPageReserved(page);
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page++;
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}
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/* Free the otherwise unused pages. */
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while (page < end) {
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__free_page(page);
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page++;
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}
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if (err) {
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free_pages(vaddr, order);
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return NULL;
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}
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return ret;
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}
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EXPORT_SYMBOL(consistent_alloc);
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/*
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* free page(s) as defined by the above mapping.
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*/
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void consistent_free(size_t size, void *vaddr)
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{
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struct page *page;
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if (in_interrupt())
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BUG();
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size = PAGE_ALIGN(size);
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#ifndef CONFIG_MMU
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/* Clear SHADOW_MASK bit in address, and free as per usual */
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# ifdef CONFIG_XILINX_UNCACHED_SHADOW
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vaddr = (void *)((unsigned)vaddr & ~UNCACHED_SHADOW_MASK);
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# endif
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page = virt_to_page(vaddr);
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do {
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__free_reserved_page(page);
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page++;
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} while (size -= PAGE_SIZE);
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#else
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do {
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pte_t *ptep;
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unsigned long pfn;
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ptep = pte_offset_kernel(pmd_offset(pgd_offset_k(
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(unsigned int)vaddr),
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(unsigned int)vaddr),
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(unsigned int)vaddr);
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if (!pte_none(*ptep) && pte_present(*ptep)) {
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pfn = pte_pfn(*ptep);
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pte_clear(&init_mm, (unsigned int)vaddr, ptep);
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if (pfn_valid(pfn)) {
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page = pfn_to_page(pfn);
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__free_reserved_page(page);
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}
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}
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vaddr += PAGE_SIZE;
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} while (size -= PAGE_SIZE);
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/* flush tlb */
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flush_tlb_all();
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#endif
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}
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EXPORT_SYMBOL(consistent_free);
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/*
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* make an area consistent.
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*/
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void consistent_sync(void *vaddr, size_t size, int direction)
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{
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unsigned long start;
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unsigned long end;
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start = (unsigned long)vaddr;
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/* Convert start address back down to unshadowed memory region */
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#ifdef CONFIG_XILINX_UNCACHED_SHADOW
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start &= ~UNCACHED_SHADOW_MASK;
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#endif
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end = start + size;
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switch (direction) {
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case PCI_DMA_NONE:
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BUG();
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case PCI_DMA_FROMDEVICE: /* invalidate only */
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invalidate_dcache_range(start, end);
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break;
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case PCI_DMA_TODEVICE: /* writeback only */
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flush_dcache_range(start, end);
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break;
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case PCI_DMA_BIDIRECTIONAL: /* writeback and invalidate */
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flush_dcache_range(start, end);
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break;
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}
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}
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EXPORT_SYMBOL(consistent_sync);
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/*
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* consistent_sync_page makes memory consistent. identical
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* to consistent_sync, but takes a struct page instead of a
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* virtual address
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*/
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void consistent_sync_page(struct page *page, unsigned long offset,
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size_t size, int direction)
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{
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unsigned long start = (unsigned long)page_address(page) + offset;
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consistent_sync((void *)start, size, direction);
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}
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EXPORT_SYMBOL(consistent_sync_page);
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