Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  linux/arch/arm/mm/consistent.c

 *

 *  Copyright (C) 2000-2004 Russell King

 *

 * 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.

 *

 *  DMA uncached mapping support.

 */

#include <linux/module.h>

#include <linux/mm.h>

#include <linux/slab.h>

#include <linux/errno.h>

#include <linux/list.h>

#include <linux/init.h>

#include <linux/device.h>

#include <linux/dma-mapping.h>

#include <asm/memory.h>

#include <asm/cacheflush.h>

#include <asm/tlbflush.h>

#include <asm/sizes.h>

/* Sanity check size */

#if (CONSISTENT_DMA_SIZE % SZ_2M)

#error "CONSISTENT_DMA_SIZE must be multiple of 2MiB"

#endif

#define CONSISTENT_END  (0xffe00000)

#define CONSISTENT_BASE (CONSISTENT_END - CONSISTENT_DMA_SIZE)

#define CONSISTENT_OFFSET(x)    (((unsigned long)(x) - CONSISTENT_BASE) >> PAGE_SHIFT)

#define CONSISTENT_PTE_INDEX(x) (((unsigned long)(x) - CONSISTENT_BASE) >> PGDIR_SHIFT)

#define NUM_CONSISTENT_PTES (CONSISTENT_DMA_SIZE >> PGDIR_SHIFT)

/*

 * These are the page tables (2MB each) covering uncached, DMA consistent allocations

 */

static pte_t *consistent_pte[NUM_CONSISTENT_PTES];

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;

        struct page             *vm_pages;

        int                     vm_active;

};

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;

        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 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_active && c->vm_start == addr)

                        goto out;

        }

        c = NULL;

 out:

        return c;

}

#ifdef CONFIG_HUGETLB_PAGE

#error ARM Coherent DMA allocator does not (yet) support huge TLB

#endif

static void *

__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,

            pgprot_t prot)

{

        struct page *page;

        struct vm_region *c;

        unsigned long order;

        u64 mask = ISA_DMA_THRESHOLD, limit;

        if (!consistent_pte[0]) {

                printk(KERN_ERR "%s: not initialised\n", __func__);

                dump_stack();

                return NULL;

        }

        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");

                        goto no_page;

                }

                if ((~mask) & ISA_DMA_THRESHOLD) {

                        dev_warn(dev, "coherent DMA mask %#llx is smaller "

                                 "than system GFP_DMA mask %#llx\n",

                                 mask, (unsigned long long)ISA_DMA_THRESHOLD);

                        goto no_page;

                }

        }

        /*

         * Sanity check the allocation size.

         */

        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 %#llx)\n", size, mask);

                goto no_page;

        }

        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 *ptr = page_address(page);

                memset(ptr, 0, size);

                dmac_flush_range(ptr, ptr + size);

                outer_flush_range(__pa(ptr), __pa(ptr) + 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;

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

                int idx = CONSISTENT_PTE_INDEX(c->vm_start);

                u32 off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);

                pte = consistent_pte[idx] + off;

                c->vm_pages = page;

                split_page(page, order);

                /*

                 * Set the "dma handle"

                 */

                *handle = page_to_dma(dev, page);

                do {

                        BUG_ON(!pte_none(*pte));

                        /*

                         * x86 does not mark the pages reserved...

                         */

                        SetPageReserved(page);

                        set_pte_ext(pte, mk_pte(page, prot), 0);

                        page++;

                        pte++;

                        off++;

                        if (off >= PTRS_PER_PTE) {

                                off = 0;

                                pte = consistent_pte[++idx];

                        }

                } 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:

        *handle = ~0;

        return NULL;

}

/*

 * Allocate DMA-coherent memory space and return both the kernel remapped

 * virtual and bus address for that space.

 */

void *

dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)

{

        if (arch_is_coherent()) {

                void *virt;

                virt = kmalloc(size, gfp);

                if (!virt)

                        return NULL;

                *handle =  virt_to_dma(dev, virt);

                return virt;

        }

        return __dma_alloc(dev, size, handle, gfp,

                           pgprot_noncached(pgprot_kernel));

}

EXPORT_SYMBOL(dma_alloc_coherent);

/*

 * Allocate a writecombining region, in much the same way as

 * dma_alloc_coherent above.

 */

void *

dma_alloc_writecombine(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)

{

        return __dma_alloc(dev, size, handle, gfp,

                           pgprot_writecombine(pgprot_kernel));

}

EXPORT_SYMBOL(dma_alloc_writecombine);

static int dma_mmap(struct device *dev, struct vm_area_struct *vma,

                    void *cpu_addr, dma_addr_t dma_addr, size_t size)

{

        unsigned long flags, user_size, kern_size;

        struct vm_region *c;

        int ret = -ENXIO;

        user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;

        spin_lock_irqsave(&consistent_lock, flags);

        c = 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;

}

int dma_mmap_coherent(struct device *dev, struct vm_area_struct *vma,

                      void *cpu_addr, dma_addr_t dma_addr, size_t size)

{

        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        return dma_mmap(dev, vma, cpu_addr, dma_addr, size);

}

EXPORT_SYMBOL(dma_mmap_coherent);

int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,

                          void *cpu_addr, dma_addr_t dma_addr, size_t size)

{

        vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

        return dma_mmap(dev, vma, cpu_addr, dma_addr, size);

}

EXPORT_SYMBOL(dma_mmap_writecombine);

/*

 * free a page as defined by the above mapping.

 * Must not be called with IRQs disabled.

 */

void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)

{

        struct vm_region *c;

        unsigned long flags, addr;

        pte_t *ptep;

        int idx;

        u32 off;

        WARN_ON(irqs_disabled());

        if (arch_is_coherent()) {

                kfree(cpu_addr);

                return;

        }

        size = PAGE_ALIGN(size);

        spin_lock_irqsave(&consistent_lock, flags);

        c = vm_region_find(&consistent_head, (unsigned long)cpu_addr);

        if (!c)

                goto no_area;

        c->vm_active = 0;

        spin_unlock_irqrestore(&consistent_lock, flags);

        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;

        }

        idx = CONSISTENT_PTE_INDEX(c->vm_start);

        off = CONSISTENT_OFFSET(c->vm_start) & (PTRS_PER_PTE-1);

        ptep = consistent_pte[idx] + off;

        addr = c->vm_start;

        do {

                pte_t pte = ptep_get_and_clear(&init_mm, addr, ptep);

                unsigned long pfn;

                ptep++;

                addr += PAGE_SIZE;

                off++;

                if (off >= PTRS_PER_PTE) {

                        off = 0;

                        ptep = consistent_pte[++idx];

                }

                if (!pte_none(pte) && pte_present(pte)) {

                        pfn = pte_pfn(pte);

                        if (pfn_valid(pfn)) {

                                struct page *page = pfn_to_page(pfn);

                                /*

                                 * x86 does not mark the pages reserved...

                                 */

                                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);

        spin_lock_irqsave(&consistent_lock, flags);

        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__, cpu_addr);

        dump_stack();

}

EXPORT_SYMBOL(dma_free_coherent);

/*

 * Initialise the consistent memory allocation.

 */

static int __init consistent_init(void)

{

        pgd_t *pgd;

        pmd_t *pmd;

        pte_t *pte;

        int ret = 0, i = 0;

        u32 base = CONSISTENT_BASE;

        do {

                pgd = pgd_offset(&init_mm, base);

                pmd = pmd_alloc(&init_mm, pgd, 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, base);

                if (!pte) {

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

                        ret = -ENOMEM;

                        break;

                }

                consistent_pte[i++] = pte;

                base += (1 << PGDIR_SHIFT);

        } while (base < CONSISTENT_END);

        return ret;

}

core_initcall(consistent_init);

/*

 * Make an area consistent for devices.

 * Note: Drivers should NOT use this function directly, as it will break

 * platforms with CONFIG_DMABOUNCE.

 * Use the driver DMA support - see dma-mapping.h (dma_sync_*)

 */

void dma_cache_maint(const void *start, size_t size, int direction)

{

        const void *end = start + size;

        BUG_ON(!virt_addr_valid(start) || !virt_addr_valid(end - 1));

        switch (direction) {

        case DMA_FROM_DEVICE:           /* invalidate only */

                dmac_inv_range(start, end);

                outer_inv_range(__pa(start), __pa(end));

                break;

        case DMA_TO_DEVICE:             /* writeback only */

                dmac_clean_range(start, end);

                outer_clean_range(__pa(start), __pa(end));

                break;

        case DMA_BIDIRECTIONAL:         /* writeback and invalidate */

                dmac_flush_range(start, end);

                outer_flush_range(__pa(start), __pa(end));

                break;

        default:

                BUG();

        }

}

EXPORT_SYMBOL(dma_cache_maint);