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Lakka-LibreELEC/projects/Samsung/patches/linux/samsung-0008-WIP-ARM-dma-mapping-implement-alloc_noncontiguous.patch
2022-10-04 10:53:58 +00:00

94 lines
2.6 KiB
Diff

From a3760f539508e81d47b21321aa42a09ce96555d3 Mon Sep 17 00:00:00 2001
From: Pavel Golikov <Paullo612@ya.ru>
Date: Fri, 24 Jun 2022 15:52:58 +0000
Subject: [PATCH 08/21] WIP: ARM/dma-mapping: implement ->alloc_noncontiguous
Implement support for allocating a non-contiguous DMA region. The
implementation is based on the ma-iommu driver.
Signed-off-by: Pavel Golikov <Paullo612@ya.ru>
---
arch/arm/mm/dma-mapping.c | 59 +++++++++++++++++++++++++++++++++++++++
1 file changed, 59 insertions(+)
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index 059cce018570..8f867cb9fe75 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -1759,6 +1759,63 @@ static void arm_iommu_unmap_sg(struct device *dev,
}
}
+static struct sg_table *arm_iommu_alloc_noncontiguous(struct device *dev,
+ size_t size, enum dma_data_direction dir, gfp_t gfp,
+ unsigned long attrs)
+{
+ struct dma_sgt_handle *sh;
+ int count;
+
+ sh = kmalloc(sizeof(*sh), gfp);
+ if (!sh)
+ return NULL;
+
+ size = PAGE_ALIGN(size);
+ count = size >> PAGE_SHIFT;
+
+ /*
+ * Following is a work-around (a.k.a. hack) to prevent pages
+ * with __GFP_COMP being passed to split_page() which cannot
+ * handle them. The real problem is that this flag probably
+ * should be 0 on ARM as it is not supported on this
+ * platform; see CONFIG_HUGETLBFS.
+ */
+ gfp &= ~(__GFP_COMP);
+
+ sh->pages = __iommu_alloc_buffer(dev, size, gfp, attrs, false);
+ if (!sh->pages)
+ goto err_sh;
+
+ if (sg_alloc_table_from_pages(&sh->sgt, sh->pages, count, 0, size,
+ GFP_KERNEL))
+ goto err_buffer;
+
+ if (arm_iommu_map_sg(dev, sh->sgt.sgl, sh->sgt.orig_nents, dir, attrs
+ ) < 1)
+ goto err_free_sg;
+
+ return &sh->sgt;
+
+err_free_sg:
+ sg_free_table(&sh->sgt);
+err_buffer:
+ __iommu_free_buffer(dev, sh->pages, size, attrs);
+err_sh:
+ kfree(sh);
+ return NULL;
+}
+
+static void arm_iommu_free_noncontiguous(struct device *dev, size_t size,
+ struct sg_table *sgt, enum dma_data_direction dir)
+{
+ struct dma_sgt_handle *sh = sgt_handle(sgt);
+
+ arm_iommu_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir, 0);
+ __iommu_free_buffer(dev, sh->pages, PAGE_ALIGN(size), 0);
+ sg_free_table(&sh->sgt);
+ kfree(sh);
+}
+
/**
* arm_iommu_sync_sg_for_cpu
* @dev: valid struct device pointer
@@ -1996,6 +2053,8 @@ static const struct dma_map_ops iommu_ops = {
.map_page = arm_iommu_map_page,
.unmap_page = arm_iommu_unmap_page,
+ .alloc_noncontiguous = arm_iommu_alloc_noncontiguous,
+ .free_noncontiguous = arm_iommu_free_noncontiguous,
.sync_single_for_cpu = arm_iommu_sync_single_for_cpu,
.sync_single_for_device = arm_iommu_sync_single_for_device,
--
2.17.1