94 lines
2.7 KiB
Diff
94 lines
2.7 KiB
Diff
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From 69abbee01268780b8ccb952555ce8362ad8a8b5e Mon Sep 17 00:00:00 2001
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From: Pavel Golikov <Paullo612@ya.ru>
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Date: Mon, 6 Jun 2022 17:57:53 +0300
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Subject: [PATCH 1/2] ARM/dma-mapping: implement ->alloc_noncontiguous
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Implement support for allocating a non-contiguous DMA region.
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Implementation is based on one in ma-iommu driver.
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Signed-off-by: Pavel Golikov <Paullo612@ya.ru>
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---
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arch/arm/mm/dma-mapping.c | 59 +++++++++++++++++++++++++++++++++++++++
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1 file changed, 59 insertions(+)
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diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
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index 4b61541853ea..bbccfba968fc 100644
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--- a/arch/arm/mm/dma-mapping.c
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+++ b/arch/arm/mm/dma-mapping.c
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@@ -1757,6 +1757,63 @@ static void arm_iommu_unmap_sg(struct device *dev,
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__iommu_unmap_sg(dev, sg, nents, dir, attrs, false);
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}
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+static struct sg_table *arm_iommu_alloc_noncontiguous(struct device *dev,
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+ size_t size, enum dma_data_direction dir, gfp_t gfp,
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+ unsigned long attrs)
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+{
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+ struct dma_sgt_handle *sh;
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+ int count;
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+
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+ sh = kmalloc(sizeof(*sh), gfp);
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+ if (!sh)
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+ return NULL;
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+
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+ size = PAGE_ALIGN(size);
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+ count = size >> PAGE_SHIFT;
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+
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+ /*
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+ * Following is a work-around (a.k.a. hack) to prevent pages
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+ * with __GFP_COMP being passed to split_page() which cannot
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+ * handle them. The real problem is that this flag probably
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+ * should be 0 on ARM as it is not supported on this
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+ * platform; see CONFIG_HUGETLBFS.
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+ */
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+ gfp &= ~(__GFP_COMP);
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+
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+ sh->pages = __iommu_alloc_buffer(dev, size, gfp, attrs, false);
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+ if (!sh->pages)
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+ goto err_sh;
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+
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+ if (sg_alloc_table_from_pages(&sh->sgt, sh->pages, count, 0, size,
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+ GFP_KERNEL))
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+ goto err_buffer;
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+
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+ if (__iommu_map_sg(dev, sh->sgt.sgl, sh->sgt.orig_nents, dir, attrs,
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+ false) < 1)
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+ goto err_free_sg;
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+
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+ return &sh->sgt;
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+
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+err_free_sg:
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+ sg_free_table(&sh->sgt);
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+err_buffer:
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+ __iommu_free_buffer(dev, sh->pages, size, attrs);
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+err_sh:
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+ kfree(sh);
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+ return NULL;
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+}
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+
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+static void arm_iommu_free_noncontiguous(struct device *dev, size_t size,
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+ struct sg_table *sgt, enum dma_data_direction dir)
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+{
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+ struct dma_sgt_handle *sh = sgt_handle(sgt);
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+
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+ __iommu_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir, 0, false);
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+ __iommu_free_buffer(dev, sh->pages, PAGE_ALIGN(size), 0);
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+ sg_free_table(&sh->sgt);
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+ kfree(sh);
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+}
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+
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/**
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* arm_iommu_sync_sg_for_cpu
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* @dev: valid struct device pointer
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@@ -1994,6 +2051,8 @@ static const struct dma_map_ops iommu_ops = {
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.map_page = arm_iommu_map_page,
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.unmap_page = arm_iommu_unmap_page,
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+ .alloc_noncontiguous = arm_iommu_alloc_noncontiguous,
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+ .free_noncontiguous = arm_iommu_free_noncontiguous,
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.sync_single_for_cpu = arm_iommu_sync_single_for_cpu,
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.sync_single_for_device = arm_iommu_sync_single_for_device,
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--
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2.25.1
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