Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  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/string.h>

#include <linux/types.h>

#include <linux/highmem.h>

#include <linux/dma-mapping.h>

#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 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 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, gfp_t 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, gfp_t 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) {

                unsigned long vaddr = c->vm_start;

                pte_t *pte = consistent_pte + CONSISTENT_OFFSET(vaddr);

                struct page *end = page + (1 << order);

                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_noncached(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;

}

EXPORT_SYMBOL(__dma_alloc_coherent);

/*

 * 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, addr;

        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);

        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);

                                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;

        pud_t *pud;

        pmd_t *pmd;

        pte_t *pte;

        int ret = 0;

        do {

                pgd = pgd_offset(&init_mm, CONSISTENT_BASE);

                pud = pud_alloc(&init_mm, pgd, CONSISTENT_BASE);

                pmd = pmd_alloc(&init_mm, pud, 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(pmd, CONSISTENT_BASE);

                if (!pte) {

                        printk(KERN_ERR "%s: no pte tables\n", __func__);

                        ret = -ENOMEM;

                        break;

                }

                consistent_pte = pte;

        } while (0);

        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;

        }

}

EXPORT_SYMBOL(__dma_sync);

#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_atomic()/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 - offset), size);

        size_t cur_size = seg_size;

        unsigned long flags, start, seg_offset = offset;

        int nr_segs = 1 + ((size - seg_size) + PAGE_SIZE - 1)/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

}

EXPORT_SYMBOL(__dma_sync_page);