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[PATCH] arm64: do not set dma masks that device connection can't handle

From Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Newsgroups linux.kernel
Subject [PATCH] arm64: do not set dma masks that device connection can't handle
Date 2017-01-06 15:40 +0100
Message-ID <sWDQt-3dX-7@gated-at.bofh.it> (permalink)
References <sWD46-2DX-23@gated-at.bofh.it>
Organization linux.* mail to news gateway

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It is possible that device is capable of 64-bit DMA addresses, and
device driver tries to set wide DMA mask, but bridge or bus used to
connect device to the system can't handle wide addresses.

With swiotlb, memory above 4G still can be used by drivers for streaming
DMA, but *dev->mask and dev->dma_coherent_mask must still keep values
that hardware handles physically.

This patch enforces that. Based on original version by
Arnd Bergmann <arnd@arndb.de>, extended with coherent mask hadnling.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
CC: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm64/Kconfig              |  3 +++
 arch/arm64/include/asm/device.h |  1 +
 arch/arm64/mm/dma-mapping.c     | 40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1117421..afb2c08 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -216,6 +216,9 @@ config NEED_DMA_MAP_STATE
 config NEED_SG_DMA_LENGTH
 	def_bool y
 
+config ARCH_HAS_DMA_SET_COHERENT_MASK
+	def_bool y
+
 config SMP
 	def_bool y
 
diff --git a/arch/arm64/include/asm/device.h b/arch/arm64/include/asm/device.h
index 243ef25..a57e7bb 100644
--- a/arch/arm64/include/asm/device.h
+++ b/arch/arm64/include/asm/device.h
@@ -22,6 +22,7 @@ struct dev_archdata {
 	void *iommu;			/* private IOMMU data */
 #endif
 	bool dma_coherent;
+	u64 parent_dma_mask;
 };
 
 struct pdev_archdata {
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index 290a84f..be3632e 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -352,6 +352,31 @@ static int __swiotlb_dma_supported(struct device *hwdev, u64 mask)
 	return 1;
 }
 
+static int __swiotlb_set_dma_mask(struct device *dev, u64 mask)
+{
+	/* device is not DMA capable */
+	if (!dev->dma_mask)
+		return -EIO;
+
+	/* mask is below swiotlb bounce buffer, so fail */
+	if (!swiotlb_dma_supported(dev, mask))
+		return -EIO;
+
+	/*
+	 * because of the swiotlb, we can return success for
+	 * larger masks, but need to ensure that bounce buffers
+	 * are used above parent_dma_mask, so set that as
+	 * the effective mask.
+	 */
+	if (mask > dev->archdata.parent_dma_mask)
+		mask = dev->archdata.parent_dma_mask;
+
+
+	*dev->dma_mask = mask;
+
+	return 0;
+}
+
 static struct dma_map_ops swiotlb_dma_ops = {
 	.alloc = __dma_alloc,
 	.free = __dma_free,
@@ -367,8 +392,23 @@ static struct dma_map_ops swiotlb_dma_ops = {
 	.sync_sg_for_device = __swiotlb_sync_sg_for_device,
 	.dma_supported = __swiotlb_dma_supported,
 	.mapping_error = swiotlb_dma_mapping_error,
+	.set_dma_mask = __swiotlb_set_dma_mask,
 };
 
+int dma_set_coherent_mask(struct device *dev, u64 mask)
+{
+	if (!dma_supported(dev, mask))
+		return -EIO;
+
+	if (get_dma_ops(dev) == &swiotlb_dma_ops &&
+	    mask > dev->archdata.parent_dma_mask)
+		mask = dev->archdata.parent_dma_mask;
+
+	dev->coherent_dma_mask = mask;
+	return 0;
+}
+EXPORT_SYMBOL(dma_set_coherent_mask);
+
 static int __init atomic_pool_init(void)
 {
 	pgprot_t prot = __pgprot(PROT_NORMAL_NC);
-- 
2.1.4

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Thread

Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Will Deacon <will.deacon@arm.com> - 2017-01-03 19:50 +0100
  Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-03 20:10 +0100
    Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Grygorii Strashko <grygorii.strashko@ti.com> - 2017-01-03 21:20 +0100
      Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-03 21:40 +0100
  Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann <arnd@arndb.de> - 2017-01-04 00:20 +0100
    Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-04 07:40 +0100
      Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann <arnd@arndb.de> - 2017-01-04 14:30 +0100
        Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-04 15:40 +0100
          Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann <arnd@arndb.de> - 2017-01-04 15:50 +0100
            Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-04 16:40 +0100
              Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann <arnd@arndb.de> - 2017-01-06 12:20 +0100
                Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-06 14:50 +0100
                [PATCH] arm64: do not set dma masks that device connection can't handle Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-06 15:40 +0100
                [PATCH] arm64: do not set dma masks that device connection can't handle Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-06 16:00 +0100
                Re: [PATCH] arm64: do not set dma masks that device connection can't  handle Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2017-01-08 08:20 +0100
                Re: [PATCH] arm64: do not set dma masks that device connection can't  handle Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-09 08:00 +0100
                Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann <arnd@linaro.org> - 2017-01-09 15:10 +0100
                Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit  DMA mask Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-09 21:40 +0100
                Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit         DMA mask Christoph Hellwig <hch@lst.de> - 2017-01-09 22:00 +0100
                NVMe vs DMA addressing limitations Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-10 07:50 +0100
                Re: NVMe vs DMA addressing limitations Christoph Hellwig <hch@lst.de> - 2017-01-10 08:10 +0100
                Re: NVMe vs DMA addressing limitations Nikita Yushchenko <nikita.yoush@cogentembedded.com> - 2017-01-10 08:40 +0100
                Re: NVMe vs DMA addressing limitations Arnd Bergmann <arnd@linaro.org> - 2017-01-10 12:10 +0100
                Re: NVMe vs DMA addressing limitations Christoph Hellwig <hch@lst.de> - 2017-01-10 15:50 +0100
                Re: NVMe vs DMA addressing limitations Arnd Bergmann <arnd@linaro.org> - 2017-01-10 16:10 +0100
                Re: NVMe vs DMA addressing limitations Sagi Grimberg <sagi@grimberg.me> - 2017-01-12 11:10 +0100
                Re: NVMe vs DMA addressing limitations Arnd Bergmann <arnd@linaro.org> - 2017-01-12 13:00 +0100
                Re: NVMe vs DMA addressing limitations Christoph Hellwig <hch@lst.de> - 2017-01-12 14:20 +0100
                Re: NVMe vs DMA addressing limitations Arnd Bergmann <arnd@linaro.org> - 2017-01-10 12:00 +0100
                Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann <arnd@linaro.org> - 2017-01-10 11:50 +0100
                Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit         DMA mask Christoph Hellwig <hch@lst.de> - 2017-01-10 15:50 +0100
                Re: [PATCH 1/2] arm64: dma_mapping: allow PCI host driver to limit DMA mask Arnd Bergmann <arnd@linaro.org> - 2017-01-10 16:10 +0100

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