ivtv-udma.c

Go to the documentation of this file.

/*
    User DMA

    Copyright (C) 2003-2004  Kevin Thayer <nufan_wfk at yahoo.com>
    Copyright (C) 2004  Chris Kennedy <[email protected]>
    Copyright (C) 2005-2007  Hans Verkuil <[email protected]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "ivtv-driver.h"
#include "ivtv-udma.h"

void ivtv_udma_get_page_info(struct ivtv_dma_page_info *dma_page, unsigned long first, unsigned long size)
{
    dma_page->uaddr = first & PAGE_MASK;
    dma_page->offset = first & ~PAGE_MASK;
    dma_page->tail = 1 + ((first+size-1) & ~PAGE_MASK);
    dma_page->first = (first & PAGE_MASK) >> PAGE_SHIFT;
    dma_page->last = ((first+size-1) & PAGE_MASK) >> PAGE_SHIFT;
    dma_page->page_count = dma_page->last - dma_page->first + 1;
    if (dma_page->page_count == 1) dma_page->tail -= dma_page->offset;
}

int ivtv_udma_fill_sg_list (struct ivtv_user_dma *dma, struct ivtv_dma_page_info *dma_page, int map_offset)
{
    int i, offset;
    unsigned long flags;

    if (map_offset < 0)
        return map_offset;

    offset = dma_page->offset;

    /* Fill SG Array with new values */
    for (i = 0; i < dma_page->page_count; i++) {
        unsigned int len = (i == dma_page->page_count - 1) ?
            dma_page->tail : PAGE_SIZE - offset;

        if (PageHighMem(dma->map[map_offset])) {
            void *src;

            if (dma->bouncemap[map_offset] == NULL)
                dma->bouncemap[map_offset] = alloc_page(GFP_KERNEL);
            if (dma->bouncemap[map_offset] == NULL)
                return -1;
            local_irq_save(flags);
            src = kmap_atomic(dma->map[map_offset]) + offset;
            memcpy(page_address(dma->bouncemap[map_offset]) + offset, src, len);
            kunmap_atomic(src);
            local_irq_restore(flags);
            sg_set_page(&dma->SGlist[map_offset], dma->bouncemap[map_offset], len, offset);
        }
        else {
            sg_set_page(&dma->SGlist[map_offset], dma->map[map_offset], len, offset);
        }
        offset = 0;
        map_offset++;
    }
    return map_offset;
}

void ivtv_udma_fill_sg_array (struct ivtv_user_dma *dma, u32 buffer_offset, u32 buffer_offset_2, u32 split) {
    int i;
    struct scatterlist *sg;

    for (i = 0, sg = dma->SGlist; i < dma->SG_length; i++, sg++) {
        dma->SGarray[i].size = cpu_to_le32(sg_dma_len(sg));
        dma->SGarray[i].src = cpu_to_le32(sg_dma_address(sg));
        dma->SGarray[i].dst = cpu_to_le32(buffer_offset);
        buffer_offset += sg_dma_len(sg);

        split -= sg_dma_len(sg);
        if (split == 0)
            buffer_offset = buffer_offset_2;
    }
}

/* User DMA Buffers */
void ivtv_udma_alloc(struct ivtv *itv)
{
    if (itv->udma.SG_handle == 0) {
        /* Map DMA Page Array Buffer */
        itv->udma.SG_handle = pci_map_single(itv->pdev, itv->udma.SGarray,
               sizeof(itv->udma.SGarray), PCI_DMA_TODEVICE);
        ivtv_udma_sync_for_cpu(itv);
    }
}

int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr,
               void __user *userbuf, int size_in_bytes)
{
    struct ivtv_dma_page_info user_dma;
    struct ivtv_user_dma *dma = &itv->udma;
    int i, err;

    IVTV_DEBUG_DMA("ivtv_udma_setup, dst: 0x%08x\n", (unsigned int)ivtv_dest_addr);

    /* Still in USE */
    if (dma->SG_length || dma->page_count) {
        IVTV_DEBUG_WARN("ivtv_udma_setup: SG_length %d page_count %d still full?\n",
               dma->SG_length, dma->page_count);
        return -EBUSY;
    }

    ivtv_udma_get_page_info(&user_dma, (unsigned long)userbuf, size_in_bytes);

    if (user_dma.page_count <= 0) {
        IVTV_DEBUG_WARN("ivtv_udma_setup: Error %d page_count from %d bytes %d offset\n",
               user_dma.page_count, size_in_bytes, user_dma.offset);
        return -EINVAL;
    }

    /* Get user pages for DMA Xfer */
    down_read(&current->mm->mmap_sem);
    err = get_user_pages(current, current->mm,
            user_dma.uaddr, user_dma.page_count, 0, 1, dma->map, NULL);
    up_read(&current->mm->mmap_sem);

    if (user_dma.page_count != err) {
        IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",
               err, user_dma.page_count);
        if (err >= 0) {
            for (i = 0; i < err; i++)
                put_page(dma->map[i]);
            return -EINVAL;
        }
        return err;
    }

    dma->page_count = user_dma.page_count;

    /* Fill SG List with new values */
    if (ivtv_udma_fill_sg_list(dma, &user_dma, 0) < 0) {
        for (i = 0; i < dma->page_count; i++) {
            put_page(dma->map[i]);
        }
        dma->page_count = 0;
        return -ENOMEM;
    }

    /* Map SG List */
    dma->SG_length = pci_map_sg(itv->pdev, dma->SGlist, dma->page_count, PCI_DMA_TODEVICE);

    /* Fill SG Array with new values */
    ivtv_udma_fill_sg_array (dma, ivtv_dest_addr, 0, -1);

    /* Tag SG Array with Interrupt Bit */
    dma->SGarray[dma->SG_length - 1].size |= cpu_to_le32(0x80000000);

    ivtv_udma_sync_for_device(itv);
    return dma->page_count;
}

void ivtv_udma_unmap(struct ivtv *itv)
{
    struct ivtv_user_dma *dma = &itv->udma;
    int i;

    IVTV_DEBUG_INFO("ivtv_unmap_user_dma\n");

    /* Nothing to free */
    if (dma->page_count == 0)
        return;

    /* Unmap Scatterlist */
    if (dma->SG_length) {
        pci_unmap_sg(itv->pdev, dma->SGlist, dma->page_count, PCI_DMA_TODEVICE);
        dma->SG_length = 0;
    }
    /* sync DMA */
    ivtv_udma_sync_for_cpu(itv);

    /* Release User Pages */
    for (i = 0; i < dma->page_count; i++) {
        put_page(dma->map[i]);
    }
    dma->page_count = 0;
}

void ivtv_udma_free(struct ivtv *itv)
{
    int i;

    /* Unmap SG Array */
    if (itv->udma.SG_handle) {
        pci_unmap_single(itv->pdev, itv->udma.SG_handle,
             sizeof(itv->udma.SGarray), PCI_DMA_TODEVICE);
    }

    /* Unmap Scatterlist */
    if (itv->udma.SG_length) {
        pci_unmap_sg(itv->pdev, itv->udma.SGlist, itv->udma.page_count, PCI_DMA_TODEVICE);
    }

    for (i = 0; i < IVTV_DMA_SG_OSD_ENT; i++) {
        if (itv->udma.bouncemap[i])
            __free_page(itv->udma.bouncemap[i]);
    }
}

void ivtv_udma_start(struct ivtv *itv)
{
    IVTV_DEBUG_DMA("start UDMA\n");
    write_reg(itv->udma.SG_handle, IVTV_REG_DECDMAADDR);
    write_reg_sync(read_reg(IVTV_REG_DMAXFER) | 0x01, IVTV_REG_DMAXFER);
    set_bit(IVTV_F_I_DMA, &itv->i_flags);
    set_bit(IVTV_F_I_UDMA, &itv->i_flags);
    clear_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags);
}

void ivtv_udma_prepare(struct ivtv *itv)
{
    unsigned long flags;

    spin_lock_irqsave(&itv->dma_reg_lock, flags);
    if (!test_bit(IVTV_F_I_DMA, &itv->i_flags))
        ivtv_udma_start(itv);
    else
        set_bit(IVTV_F_I_UDMA_PENDING, &itv->i_flags);
    spin_unlock_irqrestore(&itv->dma_reg_lock, flags);
}