Ported pcie-brcmstb bounce buffer implementation to ARM64. (#3144)

Ported pcie-brcmstb bounce buffer implementation to ARM64. This enables full 4G RAM usage on Raspberry Pi in 64-bit mode. Signed-off-by: Yaroslav Rosomakho <[email protected]> pcie-brcmstb: Correct SoC name The Pi 4 SoC is called BCM2711, not BCM2838. Fixes: "bcm2835-dma: Add proper 40-bit DMA support" Fixes: "Ported pcie-brcmstb bounce buffer implementation to ARM64." Signed-off-by: Phil Elwell <[email protected]> pcie-brcmstb-bounce64.c: dev_err() -> dev_info() for info messages "dmabounce: initialised" is not an error, so do not log it as such. Prevents screen polution on OS with "quiet" as kernel parameter. Closes #3266 pcie-brcmstb: Remove brcm_to_*, add pcie_to_dma40 The DMA framework performs the necessary address conversions for the common cases based on the dma-ranges DT property. brcm_to_pci and brcm_to_cpu were probably designed for non-DT use cases, something which isn't an issue for 2711. This second level of mapping causes breakage with a non-identity PCIe<->system address mapping, so remove it completely. The non-identity mapping also broke the DMA40 support, so add back a simple translation from PCIe to sys addresses. arm64 builds also require a wider coherent_dma_mask, otherwise the bounce buffer allocation is rejected. Signed-off-by: Phil Elwell <[email protected]>
raspberrypi · Feb 25, 2020 · 2cfb1fa · 2cfb1fa
1 parent 85dcbaa
commit 2cfb1fa
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Showing 5 changed files with 645 additions and 85 deletions.
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
@@ -31,6 +31,35 @@ void arch_dma_prep_coherent(struct page *page, size_t size)
 }
 
 #ifdef CONFIG_IOMMU_DMA
+static int __swiotlb_get_sgtable_page(struct sg_table *sgt,
+				      struct page *page, size_t size)
+{
+	int ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+
+	if (!ret)
+		sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0);
+
+	return ret;
+}
+
+static int __swiotlb_mmap_pfn(struct vm_area_struct *vma,
+			      unsigned long pfn, size_t size)
+{
+	int ret = -ENXIO;
+	unsigned long nr_vma_pages = vma_pages(vma);
+	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	unsigned long off = vma->vm_pgoff;
+
+	if (off < nr_pages && nr_vma_pages <= (nr_pages - off)) {
+		ret = remap_pfn_range(vma, vma->vm_start,
+				      pfn + off,
+				      vma->vm_end - vma->vm_start,
+				      vma->vm_page_prot);
+	}
+
+	return ret;
+}
+
 void arch_teardown_dma_ops(struct device *dev)
 {
 	dev->dma_ops = NULL;

diff --git a/drivers/pci/controller/Makefile b/drivers/pci/controller/Makefile
@@ -31,6 +31,9 @@ obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb.o
 ifdef CONFIG_ARM
 obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb-bounce.o
 endif
+ifdef CONFIG_ARM64
+obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb-bounce64.o
+endif
 
 obj-$(CONFIG_VMD) += vmd.o
 obj-$(CONFIG_PCIE_BRCMSTB) += pcie-brcmstb.o

diff --git a/drivers/pci/controller/pcie-brcmstb-bounce.h b/drivers/pci/controller/pcie-brcmstb-bounce.h
@@ -6,18 +6,18 @@
 #ifndef _PCIE_BRCMSTB_BOUNCE_H
 #define _PCIE_BRCMSTB_BOUNCE_H
 
-#ifdef CONFIG_ARM
+#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
 
 int brcm_pcie_bounce_init(struct device *dev, unsigned long buffer_size,
-			  dma_addr_t threshold);
+			  phys_addr_t threshold);
 int brcm_pcie_bounce_uninit(struct device *dev);
 int brcm_pcie_bounce_register_dev(struct device *dev);
 
 #else
 
 static inline int brcm_pcie_bounce_init(struct device *dev,
 					unsigned long buffer_size,
-					dma_addr_t threshold)
+					phys_addr_t threshold)
 {
 	return 0;
 }