From aa2105c7aa3a369ebec516d3cb91dc7eea541026 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Wed, 22 Apr 2020 13:40:59 +0200 Subject: [PATCH] drm/exynos: gem: rework scatter-list contiguity check on prime import Explicitly check if the imported buffer has been mapped as contiguous in the DMA address space, what is required by all Exynos DRM CRTC drivers. While touching this, set buffer flags depending on the availability of the IOMMU. Signed-off-by: Marek Szyprowski Signed-off-by: Inki Dae --- drivers/gpu/drm/exynos/exynos_drm_gem.c | 42 ++++++++++++++++++------- 1 file changed, 31 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c index 40514d3dcf60f..f136efb9d1ff5 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c @@ -458,6 +458,29 @@ exynos_drm_gem_prime_import_sg_table(struct drm_device *dev, int npages; int ret; + if (sgt->nents < 1) + return ERR_PTR(-EINVAL); + + /* + * Check if the provided buffer has been mapped as contiguous + * into DMA address space. + */ + if (sgt->nents > 1) { + dma_addr_t next_addr = sg_dma_address(sgt->sgl); + struct scatterlist *s; + unsigned int i; + + for_each_sg(sgt->sgl, s, sgt->nents, i) { + if (!sg_dma_len(s)) + break; + if (sg_dma_address(s) != next_addr) { + DRM_ERROR("buffer chunks must be mapped contiguously"); + return ERR_PTR(-EINVAL); + } + next_addr = sg_dma_address(s) + sg_dma_len(s); + } + } + exynos_gem = exynos_drm_gem_init(dev, attach->dmabuf->size); if (IS_ERR(exynos_gem)) { ret = PTR_ERR(exynos_gem); @@ -480,18 +503,15 @@ exynos_drm_gem_prime_import_sg_table(struct drm_device *dev, exynos_gem->sgt = sgt; - if (sgt->nents == 1) { - /* always physically continuous memory if sgt->nents is 1. */ - exynos_gem->flags |= EXYNOS_BO_CONTIG; - } else { - /* - * this case could be CONTIG or NONCONTIG type but for now - * sets NONCONTIG. - * TODO. we have to find a way that exporter can notify - * the type of its own buffer to importer. - */ + /* + * Buffer has been mapped as contiguous into DMA address space, + * but if there is IOMMU, it can be either CONTIG or NONCONTIG. + * We assume a simplified logic below: + */ + if (is_drm_iommu_supported(dev)) exynos_gem->flags |= EXYNOS_BO_NONCONTIG; - } + else + exynos_gem->flags |= EXYNOS_BO_CONTIG; return &exynos_gem->base; -- 2.39.5