--- /dev/null
+/*
+ * 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/config.h>
+#include <linux/module.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/mman.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/stddef.h>
+#include <linux/vmalloc.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/bootmem.h>
+#include <linux/highmem.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/pgalloc.h>
+#include <asm/prom.h>
+#include <asm/io.h>
+#include <asm/hardirq.h>
+#include <asm/mmu_context.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <asm/uaccess.h>
+#include <asm/smp.h>
+#include <asm/machdep.h>
+
+int map_page(unsigned long va, phys_addr_t pa, int flags);
+
+#include <asm/tlbflush.h>
+
+/*
+ * This address range defaults to a value that is safe for all
+ * platforms which currently set CONFIG_NOT_COHERENT_CACHE. It
+ * can be further configured for specific applications under
+ * the "Advanced Setup" menu. -Matt
+ */
+#define CONSISTENT_BASE (CONFIG_CONSISTENT_START)
+#define CONSISTENT_END (CONFIG_CONSISTENT_START + CONFIG_CONSISTENT_SIZE)
+#define CONSISTENT_OFFSET(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)
+
+/*
+ * This is the page table (2MB) covering uncached, DMA consistent allocations
+ */
+static pte_t *consistent_pte;
+static spinlock_t consistent_lock = SPIN_LOCK_UNLOCKED;
+
+/*
+ * 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 vm_region region;
+ * unsigned long flags;
+ * struct page **pages;
+ * unsigned int nr_pages;
+ * unsigned long phys_addr;
+ * };
+ *
+ * get_vm_area() would then call vm_region_alloc with an appropriate
+ * struct vm_region head (eg):
+ *
+ * struct 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 vm_region_alloc().
+ */
+struct vm_region {
+ struct list_head vm_list;
+ unsigned long vm_start;
+ unsigned long vm_end;
+};
+
+static struct vm_region consistent_head = {
+ .vm_list = LIST_HEAD_INIT(consistent_head.vm_list),
+ .vm_start = CONSISTENT_BASE,
+ .vm_end = CONSISTENT_END,
+};
+
+static struct vm_region *
+vm_region_alloc(struct vm_region *head, size_t size, int gfp)
+{
+ unsigned long addr = head->vm_start, end = head->vm_end - size;
+ unsigned long flags;
+ struct vm_region *c, *new;
+
+ new = kmalloc(sizeof(struct 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;
+
+ spin_unlock_irqrestore(&consistent_lock, flags);
+ return new;
+
+ nospc:
+ spin_unlock_irqrestore(&consistent_lock, flags);
+ kfree(new);
+ out:
+ return NULL;
+}
+
+static struct vm_region *vm_region_find(struct vm_region *head, unsigned long addr)
+{
+ struct vm_region *c;
+
+ list_for_each_entry(c, &head->vm_list, vm_list) {
+ if (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.
+ */
+void *
+__dma_alloc_coherent(size_t size, dma_addr_t *handle, int gfp)
+{
+ struct page *page;
+ struct vm_region *c;
+ unsigned long order;
+ u64 mask = 0x00ffffff, limit; /* ISA default */
+
+ if (!consistent_pte) {
+ printk(KERN_ERR "%s: not initialised\n", __func__);
+ dump_stack();
+ return NULL;
+ }
+
+ size = PAGE_ALIGN(size);
+ limit = (mask + 1) & ~mask;
+ if ((limit && size >= limit) || size >= (CONSISTENT_END - CONSISTENT_BASE)) {
+ printk(KERN_WARNING "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.
+ */
+ {
+ unsigned long kaddr = (unsigned long)page_address(page);
+ memset(page_address(page), 0, size);
+ flush_dcache_range(kaddr, kaddr + size);
+ }
+
+ /*
+ * Allocate a virtual address in the consistent mapping region.
+ */
+ c = vm_region_alloc(&consistent_head, size,
+ gfp & ~(__GFP_DMA | __GFP_HIGHMEM));
+ if (c) {
+ pte_t *pte = consistent_pte + CONSISTENT_OFFSET(c->vm_start);
+ struct page *end = page + (1 << order);
+
+ /*
+ * Set the "dma handle"
+ */
+ *handle = page_to_bus(page);
+
+ do {
+ BUG_ON(!pte_none(*pte));
+
+ set_page_count(page, 1);
+ SetPageReserved(page);
+ set_pte(pte, mk_pte(page, pgprot_noncached(PAGE_KERNEL)));
+ page++;
+ pte++;
+ } while (size -= PAGE_SIZE);
+
+ /*
+ * Free the otherwise unused pages.
+ */
+ while (page < end) {
+ set_page_count(page, 1);
+ __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.
+ */
+void __dma_free_coherent(size_t size, void *vaddr)
+{
+ struct vm_region *c;
+ unsigned long flags;
+ pte_t *ptep;
+
+ size = PAGE_ALIGN(size);
+
+ spin_lock_irqsave(&consistent_lock, flags);
+
+ c = vm_region_find(&consistent_head, (unsigned long)vaddr);
+ if (!c)
+ goto no_area;
+
+ if ((c->vm_end - c->vm_start) != size) {
+ printk(KERN_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);
+ do {
+ pte_t pte = ptep_get_and_clear(ptep);
+ unsigned long pfn;
+
+ ptep++;
+
+ if (!pte_none(pte) && pte_present(pte)) {
+ pfn = pte_pfn(pte);
+
+ if (pfn_valid(pfn)) {
+ struct page *page = pfn_to_page(pfn);
+ ClearPageReserved(page);
+
+ __free_page(page);
+ continue;
+ }
+ }
+
+ printk(KERN_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);
+ printk(KERN_ERR "%s: trying to free invalid coherent area: %p\n",
+ __func__, vaddr);
+ dump_stack();
+}
+EXPORT_SYMBOL(dma_free_coherent);
+
+/*
+ * Initialise the consistent memory allocation.
+ */
+static int __init dma_alloc_init(void)
+{
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+ int ret = 0;
+
+ spin_lock(&init_mm.page_table_lock);
+
+ do {
+ pgd = pgd_offset(&init_mm, CONSISTENT_BASE);
+ pmd = pmd_alloc(&init_mm, pgd, CONSISTENT_BASE);
+ if (!pmd) {
+ printk(KERN_ERR "%s: no pmd tables\n", __func__);
+ ret = -ENOMEM;
+ break;
+ }
+ WARN_ON(!pmd_none(*pmd));
+
+ pte = pte_alloc_kernel(&init_mm, pmd, CONSISTENT_BASE);
+ if (!pte) {
+ printk(KERN_ERR "%s: no pte tables\n", __func__);
+ ret = -ENOMEM;
+ break;
+ }
+
+ consistent_pte = pte;
+ } while (0);
+
+ spin_unlock(&init_mm.page_table_lock);
+
+ return ret;
+}
+
+core_initcall(dma_alloc_init);
+
+/*
+ * make an area consistent.
+ */
+void __dma_sync(void *vaddr, size_t size, int direction)
+{
+ unsigned long start = (unsigned long)vaddr;
+ unsigned long end = start + size;
+
+ switch (direction) {
+ case DMA_NONE:
+ BUG();
+ case DMA_FROM_DEVICE: /* invalidate only */
+ invalidate_dcache_range(start, end);
+ break;
+ case DMA_TO_DEVICE: /* writeback only */
+ clean_dcache_range(start, end);
+ break;
+ case DMA_BIDIRECTIONAL: /* writeback and invalidate */
+ flush_dcache_range(start, end);
+ break;
+ }
+}
+
+#ifdef CONFIG_HIGHMEM
+/*
+ * __dma_sync_page() implementation for systems using highmem.
+ * In this case, each page of a buffer must be kmapped/kunmapped
+ * in order to have a virtual address for __dma_sync(). This must
+ * not sleep so kmap_atmomic()/kunmap_atomic() are used.
+ *
+ * Note: yes, it is possible and correct to have a buffer extend
+ * beyond the first page.
+ */
+static inline void __dma_sync_page_highmem(struct page *page,
+ unsigned long offset, size_t size, int direction)
+{
+ size_t seg_size = min((size_t)PAGE_SIZE, size) - offset;
+ size_t cur_size = seg_size;
+ unsigned long flags, start, seg_offset = offset;
+ int nr_segs = PAGE_ALIGN(size + (PAGE_SIZE - offset))/PAGE_SIZE;
+ int seg_nr = 0;
+
+ local_irq_save(flags);
+
+ do {
+ start = (unsigned long)kmap_atomic(page + seg_nr,
+ KM_PPC_SYNC_PAGE) + seg_offset;
+
+ /* Sync this buffer segment */
+ __dma_sync((void *)start, seg_size, direction);
+ kunmap_atomic((void *)start, KM_PPC_SYNC_PAGE);
+ seg_nr++;
+
+ /* Calculate next buffer segment size */
+ seg_size = min((size_t)PAGE_SIZE, size - cur_size);
+
+ /* Add the segment size to our running total */
+ cur_size += seg_size;
+ seg_offset = 0;
+ } while (seg_nr < nr_segs);
+
+ local_irq_restore(flags);
+}
+#endif /* CONFIG_HIGHMEM */
+
+/*
+ * __dma_sync_page makes memory consistent. identical to __dma_sync, but
+ * takes a struct page instead of a virtual address
+ */
+void __dma_sync_page(struct page *page, unsigned long offset,
+ size_t size, int direction)
+{
+#ifdef CONFIG_HIGHMEM
+ __dma_sync_page_highmem(page, offset, size, direction);
+#else
+ unsigned long start = (unsigned long)page_address(page) + offset;
+ __dma_sync((void *)start, size, direction);
+#endif
+}
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