On Thu, 2020-10-22 at 14:23 +0200, Ard Biesheuvel wrote:
> > +/**
> > + * of_dma_get_max_cpu_address - Gets highest CPU address suitable for DMA
> > + * @np: The node to start searching from or NULL to start from the root
> > + *
> > + * Gets the highest CPU physical address that is addressable by all DMA masters
> > + * in the sub-tree pointed by np, or the whole tree if NULL is passed. If no
> > + * DMA constrained device is found, it returns PHYS_ADDR_MAX.
> > + */
> > +phys_addr_t __init of_dma_get_max_cpu_address(struct device_node *np)
> > +{
> > + phys_addr_t max_cpu_addr = PHYS_ADDR_MAX;
> > + struct of_range_parser parser;
> > + phys_addr_t subtree_max_addr;
> > + struct device_node *child;
> > + struct of_range range;
> > + const __be32 *ranges;
> > + u64 cpu_end = 0;
> > + int len;
> > +
> > + if (!np)
> > + np = of_root;
> > +
> > + ranges = of_get_property(np, "dma-ranges", &len);
> > + if (ranges && len) {
> > + of_dma_range_parser_init(&parser, np);
> > + for_each_of_range(&parser, &range)
> > + if (range.cpu_addr + range.size > cpu_end)
> > + cpu_end = range.cpu_addr + range.size;
>
>
> Shouldn't this be 'range.cpu_addr + range.size - 1' ?
Yes, I agree. In that case arm64's counterpart should be:
zone_dma_bits = max(32U, fls64(of_dma_get_max_cpu_address(NULL)));
I'll update it.
Regards,
Nicolas
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