+++ /dev/null
-/*
- * Meta version derived from arch/powerpc/lib/dma-noncoherent.c
- * Copyright (C) 2008 Imagination Technologies Ltd.
- *
- * PowerPC version derived from arch/arm/mm/consistent.c
- * Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
- *
- * Copyright (C) 2000 Russell King
- *
- * Consistent memory allocators. Used for DMA devices that want to
- * share uncached memory with the processor core. The function return
- * is the virtual address and 'dma_handle' is the physical address.
- * Mostly stolen from the ARM port, with some changes for PowerPC.
- * -- Dan
- *
- * Reorganized to get rid of the arch-specific consistent_* functions
- * and provide non-coherent implementations for the DMA API. -Matt
- *
- * Added in_interrupt() safe dma_alloc_coherent()/dma_free_coherent()
- * implementation. This is pulled straight from ARM and barely
- * modified. -Matt
- *
- * 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.
- */
-
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/export.h>
-#include <linux/string.h>
-#include <linux/types.h>
-#include <linux/highmem.h>
-#include <linux/dma-mapping.h>
-#include <linux/slab.h>
-
-#include <asm/tlbflush.h>
-#include <asm/mmu.h>
-
-#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_START) \
- >> PAGE_SHIFT)
-
-static u64 get_coherent_dma_mask(struct device *dev)
-{
- u64 mask = ~0ULL;
-
- if (dev) {
- mask = dev->coherent_dma_mask;
-
- /*
- * Sanity check the DMA mask - it must be non-zero, and
- * must be able to be satisfied by a DMA allocation.
- */
- if (mask == 0) {
- dev_warn(dev, "coherent DMA mask is unset\n");
- return 0;
- }
- }
-
- return mask;
-}
-/*
- * This is the page table (2MB) covering uncached, DMA consistent allocations
- */
-static pte_t *consistent_pte;
-static DEFINE_SPINLOCK(consistent_lock);
-
-/*
- * VM region handling support.
- *
- * This should become something generic, handling VM region allocations for
- * vmalloc and similar (ioremap, module space, etc).
- *
- * I envisage vmalloc()'s supporting vm_struct becoming:
- *
- * struct vm_struct {
- * struct metag_vm_region region;
- * unsigned long flags;
- * struct page **pages;
- * unsigned int nr_pages;
- * unsigned long phys_addr;
- * };
- *
- * get_vm_area() would then call metag_vm_region_alloc with an appropriate
- * struct metag_vm_region head (eg):
- *
- * struct metag_vm_region vmalloc_head = {
- * .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
- * .vm_start = VMALLOC_START,
- * .vm_end = VMALLOC_END,
- * };
- *
- * However, vmalloc_head.vm_start is variable (typically, it is dependent on
- * the amount of RAM found at boot time.) I would imagine that get_vm_area()
- * would have to initialise this each time prior to calling
- * metag_vm_region_alloc().
- */
-struct metag_vm_region {
- struct list_head vm_list;
- unsigned long vm_start;
- unsigned long vm_end;
- struct page *vm_pages;
- int vm_active;
-};
-
-static struct metag_vm_region consistent_head = {
- .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
- .vm_start = CONSISTENT_START,
- .vm_end = CONSISTENT_END,
-};
-
-static struct metag_vm_region *metag_vm_region_alloc(struct metag_vm_region
- *head, size_t size,
- gfp_t gfp)
-{
- unsigned long addr = head->vm_start, end = head->vm_end - size;
- unsigned long flags;
- struct metag_vm_region *c, *new;
-
- new = kmalloc(sizeof(struct metag_vm_region), gfp);
- if (!new)
- goto out;
-
- spin_lock_irqsave(&consistent_lock, flags);
-
- list_for_each_entry(c, &head->vm_list, vm_list) {
- if ((addr + size) < addr)
- goto nospc;
- if ((addr + size) <= c->vm_start)
- goto found;
- addr = c->vm_end;
- if (addr > end)
- goto nospc;
- }
-
-found:
- /*
- * Insert this entry _before_ the one we found.
- */
- list_add_tail(&new->vm_list, &c->vm_list);
- new->vm_start = addr;
- new->vm_end = addr + size;
- new->vm_active = 1;
-
- spin_unlock_irqrestore(&consistent_lock, flags);
- return new;
-
-nospc:
- spin_unlock_irqrestore(&consistent_lock, flags);
- kfree(new);
-out:
- return NULL;
-}
-
-static struct metag_vm_region *metag_vm_region_find(struct metag_vm_region
- *head, unsigned long addr)
-{
- struct metag_vm_region *c;
-
- list_for_each_entry(c, &head->vm_list, vm_list) {
- if (c->vm_active && c->vm_start == addr)
- goto out;
- }
- c = NULL;
-out:
- return c;
-}
-
-/*
- * Allocate DMA-coherent memory space and return both the kernel remapped
- * virtual and bus address for that space.
- */
-static void *metag_dma_alloc(struct device *dev, size_t size,
- dma_addr_t *handle, gfp_t gfp, unsigned long attrs)
-{
- struct page *page;
- struct metag_vm_region *c;
- unsigned long order;
- u64 mask = get_coherent_dma_mask(dev);
- u64 limit;
-
- if (!consistent_pte) {
- pr_err("%s: not initialised\n", __func__);
- dump_stack();
- return NULL;
- }
-
- if (!mask)
- goto no_page;
- size = PAGE_ALIGN(size);
- limit = (mask + 1) & ~mask;
- if ((limit && size >= limit)
- || size >= (CONSISTENT_END - CONSISTENT_START)) {
- pr_warn("coherent allocation too big (requested %#x mask %#Lx)\n",
- size, mask);
- return NULL;
- }
-
- order = get_order(size);
-
- if (mask != 0xffffffff)
- gfp |= GFP_DMA;
-
- page = alloc_pages(gfp, order);
- if (!page)
- goto no_page;
-
- /*
- * Invalidate any data that might be lurking in the
- * kernel direct-mapped region for device DMA.
- */
- {
- void *kaddr = page_address(page);
- memset(kaddr, 0, size);
- flush_dcache_region(kaddr, size);
- }
-
- /*
- * Allocate a virtual address in the consistent mapping region.
- */
- c = metag_vm_region_alloc(&consistent_head, size,
- gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
- if (c) {
- unsigned long vaddr = c->vm_start;
- pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr);
- struct page *end = page + (1 << order);
-
- c->vm_pages = page;
- split_page(page, order);
-
- /*
- * Set the "dma handle"
- */
- *handle = page_to_bus(page);
-
- do {
- BUG_ON(!pte_none(*pte));
-
- SetPageReserved(page);
- set_pte_at(&init_mm, vaddr,
- pte, mk_pte(page,
- pgprot_writecombine
- (PAGE_KERNEL)));
- page++;
- pte++;
- vaddr += PAGE_SIZE;
- } while (size -= PAGE_SIZE);
-
- /*
- * Free the otherwise unused pages.
- */
- while (page < end) {
- __free_page(page);
- page++;
- }
-
- return (void *)c->vm_start;
- }
-
- if (page)
- __free_pages(page, order);
-no_page:
- return NULL;
-}
-
-/*
- * free a page as defined by the above mapping.
- */
-static void metag_dma_free(struct device *dev, size_t size, void *vaddr,
- dma_addr_t dma_handle, unsigned long attrs)
-{
- struct metag_vm_region *c;
- unsigned long flags, addr;
- pte_t *ptep;
-
- size = PAGE_ALIGN(size);
-
- spin_lock_irqsave(&consistent_lock, flags);
-
- c = metag_vm_region_find(&consistent_head, (unsigned long)vaddr);
- if (!c)
- goto no_area;
-
- c->vm_active = 0;
- if ((c->vm_end - c->vm_start) != size) {
- pr_err("%s: freeing wrong coherent size (%ld != %d)\n",
- __func__, c->vm_end - c->vm_start, size);
- dump_stack();
- size = c->vm_end - c->vm_start;
- }
-
- ptep = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
- addr = c->vm_start;
- do {
- pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);
- unsigned long pfn;
-
- ptep++;
- addr += PAGE_SIZE;
-
- if (!pte_none(pte) && pte_present(pte)) {
- pfn = pte_pfn(pte);
-
- if (pfn_valid(pfn)) {
- struct page *page = pfn_to_page(pfn);
- __free_reserved_page(page);
- continue;
- }
- }
-
- pr_crit("%s: bad page in kernel page table\n",
- __func__);
- } while (size -= PAGE_SIZE);
-
- flush_tlb_kernel_range(c->vm_start, c->vm_end);
-
- list_del(&c->vm_list);
-
- spin_unlock_irqrestore(&consistent_lock, flags);
-
- kfree(c);
- return;
-
-no_area:
- spin_unlock_irqrestore(&consistent_lock, flags);
- pr_err("%s: trying to free invalid coherent area: %p\n",
- __func__, vaddr);
- dump_stack();
-}
-
-static int metag_dma_mmap(struct device *dev, struct vm_area_struct *vma,
- void *cpu_addr, dma_addr_t dma_addr, size_t size,
- unsigned long attrs)
-{
- unsigned long flags, user_size, kern_size;
- struct metag_vm_region *c;
- int ret = -ENXIO;
-
- if (attrs & DMA_ATTR_WRITE_COMBINE)
- vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
- else
- vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-
- user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
-
- spin_lock_irqsave(&consistent_lock, flags);
- c = metag_vm_region_find(&consistent_head, (unsigned long)cpu_addr);
- spin_unlock_irqrestore(&consistent_lock, flags);
-
- if (c) {
- unsigned long off = vma->vm_pgoff;
-
- kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
-
- if (off < kern_size &&
- user_size <= (kern_size - off)) {
- ret = remap_pfn_range(vma, vma->vm_start,
- page_to_pfn(c->vm_pages) + off,
- user_size << PAGE_SHIFT,
- vma->vm_page_prot);
- }
- }
-
-
- return ret;
-}
-
-/*
- * Initialise the consistent memory allocation.
- */
-static int __init dma_alloc_init(void)
-{
- pgd_t *pgd, *pgd_k;
- pud_t *pud, *pud_k;
- pmd_t *pmd, *pmd_k;
- pte_t *pte;
- int ret = 0;
-
- do {
- int offset = pgd_index(CONSISTENT_START);
- pgd = pgd_offset(&init_mm, CONSISTENT_START);
- pud = pud_alloc(&init_mm, pgd, CONSISTENT_START);
- pmd = pmd_alloc(&init_mm, pud, CONSISTENT_START);
- WARN_ON(!pmd_none(*pmd));
-
- pte = pte_alloc_kernel(pmd, CONSISTENT_START);
- if (!pte) {
- pr_err("%s: no pte tables\n", __func__);
- ret = -ENOMEM;
- break;
- }
-
- pgd_k = ((pgd_t *) mmu_get_base()) + offset;
- pud_k = pud_offset(pgd_k, CONSISTENT_START);
- pmd_k = pmd_offset(pud_k, CONSISTENT_START);
- set_pmd(pmd_k, *pmd);
-
- consistent_pte = pte;
- } while (0);
-
- return ret;
-}
-early_initcall(dma_alloc_init);
-
-/*
- * make an area consistent to devices.
- */
-static void dma_sync_for_device(void *vaddr, size_t size, int dma_direction)
-{
- /*
- * Ensure any writes get through the write combiner. This is necessary
- * even with DMA_FROM_DEVICE, or the write may dirty the cache after
- * we've invalidated it and get written back during the DMA.
- */
-
- barrier();
-
- switch (dma_direction) {
- case DMA_BIDIRECTIONAL:
- /*
- * Writeback to ensure the device can see our latest changes and
- * so that we have no dirty lines, and invalidate the cache
- * lines too in preparation for receiving the buffer back
- * (dma_sync_for_cpu) later.
- */
- flush_dcache_region(vaddr, size);
- break;
- case DMA_TO_DEVICE:
- /*
- * Writeback to ensure the device can see our latest changes.
- * There's no need to invalidate as the device shouldn't write
- * to the buffer.
- */
- writeback_dcache_region(vaddr, size);
- break;
- case DMA_FROM_DEVICE:
- /*
- * Invalidate to ensure we have no dirty lines that could get
- * written back during the DMA. It's also safe to flush
- * (writeback) here if necessary.
- */
- invalidate_dcache_region(vaddr, size);
- break;
- case DMA_NONE:
- BUG();
- }
-
- wmb();
-}
-
-/*
- * make an area consistent to the core.
- */
-static void dma_sync_for_cpu(void *vaddr, size_t size, int dma_direction)
-{
- /*
- * Hardware L2 cache prefetch doesn't occur across 4K physical
- * boundaries, however according to Documentation/DMA-API-HOWTO.txt
- * kmalloc'd memory is DMA'able, so accesses in nearby memory could
- * trigger a cache fill in the DMA buffer.
- *
- * This should never cause dirty lines, so a flush or invalidate should
- * be safe to allow us to see data from the device.
- */
- if (_meta_l2c_pf_is_enabled()) {
- switch (dma_direction) {
- case DMA_BIDIRECTIONAL:
- case DMA_FROM_DEVICE:
- invalidate_dcache_region(vaddr, size);
- break;
- case DMA_TO_DEVICE:
- /* The device shouldn't have written to the buffer */
- break;
- case DMA_NONE:
- BUG();
- }
- }
-
- rmb();
-}
-
-static dma_addr_t metag_dma_map_page(struct device *dev, struct page *page,
- unsigned long offset, size_t size,
- enum dma_data_direction direction, unsigned long attrs)
-{
- if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
- dma_sync_for_device((void *)(page_to_phys(page) + offset),
- size, direction);
- return page_to_phys(page) + offset;
-}
-
-static void metag_dma_unmap_page(struct device *dev, dma_addr_t dma_address,
- size_t size, enum dma_data_direction direction,
- unsigned long attrs)
-{
- if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
- dma_sync_for_cpu(phys_to_virt(dma_address), size, direction);
-}
-
-static int metag_dma_map_sg(struct device *dev, struct scatterlist *sglist,
- int nents, enum dma_data_direction direction,
- unsigned long attrs)
-{
- struct scatterlist *sg;
- int i;
-
- for_each_sg(sglist, sg, nents, i) {
- BUG_ON(!sg_page(sg));
-
- sg->dma_address = sg_phys(sg);
-
- if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
- continue;
-
- dma_sync_for_device(sg_virt(sg), sg->length, direction);
- }
-
- return nents;
-}
-
-
-static void metag_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
- int nhwentries, enum dma_data_direction direction,
- unsigned long attrs)
-{
- struct scatterlist *sg;
- int i;
-
- for_each_sg(sglist, sg, nhwentries, i) {
- BUG_ON(!sg_page(sg));
-
- sg->dma_address = sg_phys(sg);
-
- if (attrs & DMA_ATTR_SKIP_CPU_SYNC)
- continue;
-
- dma_sync_for_cpu(sg_virt(sg), sg->length, direction);
- }
-}
-
-static void metag_dma_sync_single_for_cpu(struct device *dev,
- dma_addr_t dma_handle, size_t size,
- enum dma_data_direction direction)
-{
- dma_sync_for_cpu(phys_to_virt(dma_handle), size, direction);
-}
-
-static void metag_dma_sync_single_for_device(struct device *dev,
- dma_addr_t dma_handle, size_t size,
- enum dma_data_direction direction)
-{
- dma_sync_for_device(phys_to_virt(dma_handle), size, direction);
-}
-
-static void metag_dma_sync_sg_for_cpu(struct device *dev,
- struct scatterlist *sglist, int nelems,
- enum dma_data_direction direction)
-{
- int i;
- struct scatterlist *sg;
-
- for_each_sg(sglist, sg, nelems, i)
- dma_sync_for_cpu(sg_virt(sg), sg->length, direction);
-}
-
-static void metag_dma_sync_sg_for_device(struct device *dev,
- struct scatterlist *sglist, int nelems,
- enum dma_data_direction direction)
-{
- int i;
- struct scatterlist *sg;
-
- for_each_sg(sglist, sg, nelems, i)
- dma_sync_for_device(sg_virt(sg), sg->length, direction);
-}
-
-const struct dma_map_ops metag_dma_ops = {
- .alloc = metag_dma_alloc,
- .free = metag_dma_free,
- .map_page = metag_dma_map_page,
- .map_sg = metag_dma_map_sg,
- .sync_single_for_device = metag_dma_sync_single_for_device,
- .sync_single_for_cpu = metag_dma_sync_single_for_cpu,
- .sync_sg_for_cpu = metag_dma_sync_sg_for_cpu,
- .mmap = metag_dma_mmap,
-};
-EXPORT_SYMBOL(metag_dma_ops);
git.samba.org / sfrench / cifs-2.6.git / blobdiff