mirror of https://gitee.com/openkylin/linux.git
a7ba70f178
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> |
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| .. | ||
| Makefile | ||
| acpi.c | ||
| amd_bus.c | ||
| broadcom_bus.c | ||
| bus_numa.c | ||
| bus_numa.h | ||
| ce4100.c | ||
| common.c | ||
| direct.c | ||
| early.c | ||
| fixup.c | ||
| i386.c | ||
| init.c | ||
| intel_mid_pci.c | ||
| irq.c | ||
| legacy.c | ||
| mmconfig-shared.c | ||
| mmconfig_32.c | ||
| mmconfig_64.c | ||
| numachip.c | ||
| olpc.c | ||
| pcbios.c | ||
| sta2x11-fixup.c | ||
| xen.c | ||