Hi, Alexandre:
On Tue, 2019-07-23 at 14:34 +0900, Alexandre Courbot wrote:
> This driver requires imported PRIME buffers to appear contiguously in
> its IO address space. Make sure this is the case by setting the maximum
> DMA segment size to a better value than the default 64K on the DMA
> device, and use said DMA device when importing PRIME buffers.
>
> Signed-off-by: Alexandre Courbot <acour...@chromium.org>
> ---
> drivers/gpu/drm/mediatek/mtk_drm_drv.c | 47 ++++++++++++++++++++++++--
> drivers/gpu/drm/mediatek/mtk_drm_drv.h | 2 ++
> 2 files changed, 46 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> index 95fdbd0fbcac..4ad4770fab13 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
> @@ -213,6 +213,7 @@ static int mtk_drm_kms_init(struct drm_device *drm)
> struct mtk_drm_private *private = drm->dev_private;
> struct platform_device *pdev;
> struct device_node *np;
> + struct device *dma_dev;
> int ret;
>
> if (!iommu_present(&platform_bus_type))
> @@ -275,7 +276,27 @@ static int mtk_drm_kms_init(struct drm_device *drm)
> goto err_component_unbind;
> }
>
> - private->dma_dev = &pdev->dev;
> + dma_dev = &pdev->dev;
> + private->dma_dev = dma_dev;
> +
> + /*
> + * Configure the DMA segment size to make sure we get contiguous IOVA
> + * when importing PRIME buffers.
> + */
> + if (!dma_dev->dma_parms) {
> + private->dma_parms_allocated = true;
> + dma_dev->dma_parms =
> + devm_kzalloc(drm->dev, sizeof(*dma_dev->dma_parms),
> + GFP_KERNEL);
> + }
> + if (!dma_dev->dma_parms)
> + goto err_component_unbind;
return with ret = 0?
> +
> + ret = dma_set_max_seg_size(dma_dev, (unsigned int)DMA_BIT_MASK(32));
> + if (ret) {
> + dev_err(dma_dev, "Failed to set DMA segment size\n");
> + goto err_unset_dma_parms;
> + }
>
> /*
> * We don't use the drm_irq_install() helpers provided by the DRM
> @@ -285,13 +306,16 @@ static int mtk_drm_kms_init(struct drm_device *drm)
> drm->irq_enabled = true;
> ret = drm_vblank_init(drm, MAX_CRTC);
> if (ret < 0)
> - goto err_component_unbind;
> + goto err_unset_dma_parms;
>
> drm_kms_helper_poll_init(drm);
> drm_mode_config_reset(drm);
>
> return 0;
>
> +err_unset_dma_parms:
> + if (private->dma_parms_allocated)
> + dma_dev->dma_parms = NULL;
> err_component_unbind:
> component_unbind_all(drm->dev, drm);
> err_config_cleanup:
> @@ -302,9 +326,14 @@ static int mtk_drm_kms_init(struct drm_device *drm)
>
> static void mtk_drm_kms_deinit(struct drm_device *drm)
> {
> + struct mtk_drm_private *private = drm->dev_private;
> +
> drm_kms_helper_poll_fini(drm);
> drm_atomic_helper_shutdown(drm);
>
> + if (private->dma_parms_allocated)
> + private->dma_dev->dma_parms = NULL;
> +
> component_unbind_all(drm->dev, drm);
> drm_mode_config_cleanup(drm);
> }
> @@ -320,6 +349,18 @@ static const struct file_operations mtk_drm_fops = {
> .compat_ioctl = drm_compat_ioctl,
> };
>
> +/*
> + * We need to override this because the device used to import the memory is
> + * not dev->dev, as drm_gem_prime_import() expects.
> + */
> +struct drm_gem_object *mtk_drm_gem_prime_import(struct drm_device *dev,
> + struct dma_buf *dma_buf)
> +{
> + struct mtk_drm_private *private = dev->dev_private;
> +
> + return drm_gem_prime_import_dev(dev, dma_buf, private->dma_dev);
> +}
> +
I think this part should be an independent patch which fixup
119f5173628aa ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Regards,
CK
> static struct drm_driver mtk_drm_driver = {
> .driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME |
> DRIVER_ATOMIC,
> @@ -331,7 +372,7 @@ static struct drm_driver mtk_drm_driver = {
> .prime_handle_to_fd = drm_gem_prime_handle_to_fd,
> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> .gem_prime_export = drm_gem_prime_export,
> - .gem_prime_import = drm_gem_prime_import,
> + .gem_prime_import = mtk_drm_gem_prime_import,
> .gem_prime_get_sg_table = mtk_gem_prime_get_sg_table,
> .gem_prime_import_sg_table = mtk_gem_prime_import_sg_table,
> .gem_prime_mmap = mtk_drm_gem_mmap_buf,
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> index 598ff3e70446..e03fea12ff59 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> @@ -51,6 +51,8 @@ struct mtk_drm_private {
> } commit;
>
> struct drm_atomic_state *suspend_state;
> +
> + bool dma_parms_allocated;
> };
>
> extern struct platform_driver mtk_ddp_driver;
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