diff options
Diffstat (limited to 'kernel/dma')
| -rw-r--r-- | kernel/dma/mapping.c | 30 |
1 files changed, 10 insertions, 20 deletions
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index 285de5fbc8e9..64a3d294f4b4 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -271,25 +271,6 @@ int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, } EXPORT_SYMBOL(dma_mmap_attrs); -static u64 dma_default_get_required_mask(struct device *dev) -{ - u32 low_totalram = ((max_pfn - 1) << PAGE_SHIFT); - u32 high_totalram = ((max_pfn - 1) >> (32 - PAGE_SHIFT)); - u64 mask; - - if (!high_totalram) { - /* convert to mask just covering totalram */ - low_totalram = (1 << (fls(low_totalram) - 1)); - low_totalram += low_totalram - 1; - mask = low_totalram; - } else { - high_totalram = (1 << (fls(high_totalram) - 1)); - high_totalram += high_totalram - 1; - mask = (((u64)high_totalram) << 32) + 0xffffffff; - } - return mask; -} - u64 dma_get_required_mask(struct device *dev) { const struct dma_map_ops *ops = get_dma_ops(dev); @@ -298,7 +279,16 @@ u64 dma_get_required_mask(struct device *dev) return dma_direct_get_required_mask(dev); if (ops->get_required_mask) return ops->get_required_mask(dev); - return dma_default_get_required_mask(dev); + + /* + * We require every DMA ops implementation to at least support a 32-bit + * DMA mask (and use bounce buffering if that isn't supported in + * hardware). As the direct mapping code has its own routine to + * actually report an optimal mask we default to 32-bit here as that + * is the right thing for most IOMMUs, and at least not actively + * harmful in general. + */ + return DMA_BIT_MASK(32); } EXPORT_SYMBOL_GPL(dma_get_required_mask); |