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authorNicolas Saenz Julienne <nsaenzjulienne@suse.de>2019-11-21 10:26:44 +0100
committerChristoph Hellwig <hch@lst.de>2019-11-21 18:14:35 +0100
commita7ba70f1787f977f970cd116076c6fce4b9e01cc (patch)
tree474b2c0bc2201b3d2adde4c7887d4f76d50ac753 /arch/x86
parentMerge branch 'for-next/zone-dma' of git://git.kernel.org/pub/scm/linux/kernel... (diff)
downloadlinux-a7ba70f1787f977f970cd116076c6fce4b9e01cc.tar.xz
linux-a7ba70f1787f977f970cd116076c6fce4b9e01cc.zip
dma-mapping: treat dev->bus_dma_mask as a DMA limit
Using a mask to represent bus DMA constraints has a set of limitations. The biggest one being it can only hold a power of two (minus one). The DMA mapping code is already aware of this and treats dev->bus_dma_mask as a limit. This quirk is already used by some architectures although still rare. With the introduction of the Raspberry Pi 4 we've found a new contender for the use of bus DMA limits, as its PCIe bus can only address the lower 3GB of memory (of a total of 4GB). This is impossible to represent with a mask. To make things worse the device-tree code rounds non power of two bus DMA limits to the next power of two, which is unacceptable in this case. In the light of this, rename dev->bus_dma_mask to dev->bus_dma_limit all over the tree and treat it as such. Note that dev->bus_dma_limit should contain the higher accessible DMA address. Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/pci-dma.c2
-rw-r--r--arch/x86/mm/mem_encrypt.c2
-rw-r--r--arch/x86/pci/sta2x11-fixup.c2
3 files changed, 3 insertions, 3 deletions
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index fa4352dce491..3a75d665d43c 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -146,7 +146,7 @@ rootfs_initcall(pci_iommu_init);
static int via_no_dac_cb(struct pci_dev *pdev, void *data)
{
- pdev->dev.bus_dma_mask = DMA_BIT_MASK(32);
+ pdev->dev.bus_dma_limit = DMA_BIT_MASK(32);
return 0;
}
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 9268c12458c8..a03614bd3e1a 100644
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -367,7 +367,7 @@ bool force_dma_unencrypted(struct device *dev)
if (sme_active()) {
u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask));
u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask,
- dev->bus_dma_mask);
+ dev->bus_dma_limit);
if (dma_dev_mask <= dma_enc_mask)
return true;
diff --git a/arch/x86/pci/sta2x11-fixup.c b/arch/x86/pci/sta2x11-fixup.c
index 4a631264b809..c313d784efab 100644
--- a/arch/x86/pci/sta2x11-fixup.c
+++ b/arch/x86/pci/sta2x11-fixup.c
@@ -143,7 +143,7 @@ static void sta2x11_map_ep(struct pci_dev *pdev)
dev->dma_pfn_offset = PFN_DOWN(-amba_base);
- dev->bus_dma_mask = max_amba_addr;
+ dev->bus_dma_limit = max_amba_addr;
pci_set_consistent_dma_mask(pdev, max_amba_addr);
pci_set_dma_mask(pdev, max_amba_addr);