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From e3218ab51b0bf3f193a9f64e5c0dafe74e292ad2 Mon Sep 17 00:00:00 2001
From: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Date: Fri, 6 Jan 2017 17:12:49 +0300
Subject: [PATCH] arm64: do not set dma masks that device connection can't
handle
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 | 51 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 55 insertions(+)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 76747d92bc72..9513d2eb5c8a 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -191,6 +191,9 @@ 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 243ef256b8c9..a57e7bb10e71 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 46a4157adc17..04b9bce96f1b 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -351,6 +351,30 @@ 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,
@@ -366,8 +390,23 @@ 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);
@@ -971,6 +1010,18 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
if (!dev->archdata.dma_ops)
dev->archdata.dma_ops = &swiotlb_dma_ops;
+ /*
+ * we don't yet support buses that have a non-zero mapping.
+ * Let's hope we won't need it
+ */
+ WARN_ON(dma_base != 0);
+
+ /*
+ * Whatever the parent bus can set. A device must not set
+ * a DMA mask larger than this.
+ */
+ dev->archdata.parent_dma_mask = size - 1;
+
dev->archdata.dma_coherent = coherent;
__iommu_setup_dma_ops(dev, dma_base, size, iommu);
}
--
2.11.0
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