On Mon, Aug 24, 2020 at 03:30:20PM -0400, Jim Quinlan wrote:
> The new field 'dma_range_map' in struct device is used to facilitate the
> use of single or multiple offsets between mapping regions of cpu addrs and
> dma addrs. It subsumes the role of "dev->dma_pfn_offset" which was only
> capable of holding a single uniform offset and had no region bounds
> checking.
>
> The function of_dma_get_range() has been modified so that it takes a single
> argument -- the device node -- and returns a map, NULL, or an error code.
> The map is an array that holds the information regarding the DMA regions.
> Each range entry contains the address offset, the cpu_start address, the
> dma_start address, and the size of the region.
>
> of_dma_configure() is the typical manner to set range offsets but there are
> a number of ad hoc assignments to "dev->dma_pfn_offset" in the kernel
> driver code. These cases now invoke the function
> dma_attach_offset_range(dev, cpu_addr, dma_addr, size).
...
> + /*
> + * Record all info in the generic DMA ranges array for struct device.
> + */
> + *map = r;
> + for_each_of_range(&parser, &range) {
> + pr_debug("dma_addr(%llx) cpu_addr(%llx) size(%llx)\n",
> + range.bus_addr, range.cpu_addr, range.size);
> + r->cpu_start = range.cpu_addr;
> + r->dma_start = range.bus_addr;
> + r->size = range.size;
> + r->offset = (u64)range.cpu_addr - (u64)range.bus_addr;
What's the point in explicit castings to the same type?
> + r++;
> + }
...
> + phys_addr_t paddr;
> + dma_addr_t dma_addr;
> + struct device dev_bogus;
> unittest(paddr == expect_paddr,
> - "of_dma_get_range wrong phys addr (%llx) on node
> %pOF", paddr, np);
> + "of_dma_get_range: wrong phys addr %llx (expecting
> %llx) on node %pOF\n",
> + (u64)paddr, expect_paddr, np);
%llx -> %pap
> unittest(dma_addr == expect_dma_addr,
> - "of_dma_get_range wrong DMA addr (%llx) on node %pOF",
> dma_addr, np);
> + "of_dma_get_range: wrong DMA addr %llx (expecting
> %llx) on node %pOF\n",
> + (u64)dma_addr, expect_dma_addr, np);
%llx -> %pad
...
> + if (mem->use_dev_dma_pfn_offset) {
> + u64 base_addr = PFN_PHYS((u64)mem->pfn_base);
Do we need explicit casting here?
> +
> + return base_addr - dma_offset_from_phys_addr(dev, base_addr);
> + }
...
> +int dma_set_offset_range(struct device *dev, phys_addr_t cpu_start,
> + dma_addr_t dma_start, u64 size)
> +{
> + struct bus_dma_region *map;
> + u64 offset = (u64)cpu_start - (u64)dma_start;
> +
> + if (dev->dma_range_map) {
> + dev_err(dev, "attempt to add DMA range to existing map\n");
> + return -EINVAL;
> + }
Wouldn't be better to do an assignment of offset here?
> + if (!offset)
> + return 0;
> +
> + map = kcalloc(2, sizeof(*map), GFP_KERNEL);
> + if (!map)
> + return -ENOMEM;
> + map[0].cpu_start = cpu_start;
> + map[0].dma_start = dma_start;
> + map[0].offset = offset;
> + map[0].size = size;
> + dev->dma_range_map = map;
> +
> + return 0;
> +}
--
With Best Regards,
Andy Shevchenko
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