exynos_drm_buf.c

Go to the documentation of this file.

/* exynos_drm_buf.c
 *
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 * Author: Inki Dae <[email protected]>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include <drm/drmP.h>
#include <drm/exynos_drm.h>

#include "exynos_drm_drv.h"
#include "exynos_drm_gem.h"
#include "exynos_drm_buf.h"

static int lowlevel_buffer_allocate(struct drm_device *dev,
        unsigned int flags, struct exynos_drm_gem_buf *buf)
{
    dma_addr_t start_addr;
    unsigned int npages, i = 0;
    struct scatterlist *sgl;
    int ret = 0;

    DRM_DEBUG_KMS("%s\n", __FILE__);

    if (IS_NONCONTIG_BUFFER(flags)) {
        DRM_DEBUG_KMS("not support allocation type.\n");
        return -EINVAL;
    }

    if (buf->dma_addr) {
        DRM_DEBUG_KMS("already allocated.\n");
        return 0;
    }

    if (buf->size >= SZ_1M) {
        npages = buf->size >> SECTION_SHIFT;
        buf->page_size = SECTION_SIZE;
    } else if (buf->size >= SZ_64K) {
        npages = buf->size >> 16;
        buf->page_size = SZ_64K;
    } else {
        npages = buf->size >> PAGE_SHIFT;
        buf->page_size = PAGE_SIZE;
    }

    buf->sgt = kzalloc(sizeof(struct sg_table), GFP_KERNEL);
    if (!buf->sgt) {
        DRM_ERROR("failed to allocate sg table.\n");
        return -ENOMEM;
    }

    ret = sg_alloc_table(buf->sgt, npages, GFP_KERNEL);
    if (ret < 0) {
        DRM_ERROR("failed to initialize sg table.\n");
        kfree(buf->sgt);
        buf->sgt = NULL;
        return -ENOMEM;
    }

    buf->kvaddr = dma_alloc_writecombine(dev->dev, buf->size,
            &buf->dma_addr, GFP_KERNEL);
    if (!buf->kvaddr) {
        DRM_ERROR("failed to allocate buffer.\n");
        ret = -ENOMEM;
        goto err1;
    }

    buf->pages = kzalloc(sizeof(struct page) * npages, GFP_KERNEL);
    if (!buf->pages) {
        DRM_ERROR("failed to allocate pages.\n");
        ret = -ENOMEM;
        goto err2;
    }

    sgl = buf->sgt->sgl;
    start_addr = buf->dma_addr;

    while (i < npages) {
        buf->pages[i] = phys_to_page(start_addr);
        sg_set_page(sgl, buf->pages[i], buf->page_size, 0);
        sg_dma_address(sgl) = start_addr;
        start_addr += buf->page_size;
        sgl = sg_next(sgl);
        i++;
    }

    DRM_DEBUG_KMS("vaddr(0x%lx), dma_addr(0x%lx), size(0x%lx)\n",
            (unsigned long)buf->kvaddr,
            (unsigned long)buf->dma_addr,
            buf->size);

    return ret;
err2:
    dma_free_writecombine(dev->dev, buf->size, buf->kvaddr,
            (dma_addr_t)buf->dma_addr);
    buf->dma_addr = (dma_addr_t)NULL;
err1:
    sg_free_table(buf->sgt);
    kfree(buf->sgt);
    buf->sgt = NULL;

    return ret;
}

static void lowlevel_buffer_deallocate(struct drm_device *dev,
        unsigned int flags, struct exynos_drm_gem_buf *buf)
{
    DRM_DEBUG_KMS("%s.\n", __FILE__);

    /*
     * release only physically continuous memory and
     * non-continuous memory would be released by exynos
     * gem framework.
     */
    if (IS_NONCONTIG_BUFFER(flags)) {
        DRM_DEBUG_KMS("not support allocation type.\n");
        return;
    }

    if (!buf->dma_addr) {
        DRM_DEBUG_KMS("dma_addr is invalid.\n");
        return;
    }

    DRM_DEBUG_KMS("vaddr(0x%lx), dma_addr(0x%lx), size(0x%lx)\n",
            (unsigned long)buf->kvaddr,
            (unsigned long)buf->dma_addr,
            buf->size);

    sg_free_table(buf->sgt);

    kfree(buf->sgt);
    buf->sgt = NULL;

    kfree(buf->pages);
    buf->pages = NULL;

    dma_free_writecombine(dev->dev, buf->size, buf->kvaddr,
                (dma_addr_t)buf->dma_addr);
    buf->dma_addr = (dma_addr_t)NULL;
}

struct exynos_drm_gem_buf *exynos_drm_init_buf(struct drm_device *dev,
                        unsigned int size)
{
    struct exynos_drm_gem_buf *buffer;

    DRM_DEBUG_KMS("%s.\n", __FILE__);
    DRM_DEBUG_KMS("desired size = 0x%x\n", size);

    buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
    if (!buffer) {
        DRM_ERROR("failed to allocate exynos_drm_gem_buf.\n");
        return NULL;
    }

    buffer->size = size;
    return buffer;
}

void exynos_drm_fini_buf(struct drm_device *dev,
                struct exynos_drm_gem_buf *buffer)
{
    DRM_DEBUG_KMS("%s.\n", __FILE__);

    if (!buffer) {
        DRM_DEBUG_KMS("buffer is null.\n");
        return;
    }

    kfree(buffer);
    buffer = NULL;
}

int exynos_drm_alloc_buf(struct drm_device *dev,
        struct exynos_drm_gem_buf *buf, unsigned int flags)
{

    /*
     * allocate memory region and set the memory information
     * to vaddr and dma_addr of a buffer object.
     */
    if (lowlevel_buffer_allocate(dev, flags, buf) < 0)
        return -ENOMEM;

    return 0;
}

void exynos_drm_free_buf(struct drm_device *dev,
        unsigned int flags, struct exynos_drm_gem_buf *buffer)
{

    lowlevel_buffer_deallocate(dev, flags, buffer);
}