drivers/acpi/arm64/dma.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 #include <linux/acpi.h>
   3 #include <linux/acpi_iort.h>
   4 #include <linux/device.h>
   5 #include <linux/dma-direct.h>
   6
   7 void acpi_arch_dma_setup(struct device *dev)
   8 {
   9         int ret;
  10         u64 end, mask;
  11         const struct bus_dma_region *map = NULL;
  12
  13         /*
  14          * If @dev is expected to be DMA-capable then the bus code that created
  15          * it should have initialised its dma_mask pointer by this point. For
  16          * now, we'll continue the legacy behaviour of coercing it to the
  17          * coherent mask if not, but we'll no longer do so quietly.
  18          */
  19         if (!dev->dma_mask) {
  20                 dev_warn(dev, "DMA mask not set\n");
  21                 dev->dma_mask = &dev->coherent_dma_mask;
  22         }
  23
  24         if (dev->coherent_dma_mask)
  25                 end = dev->coherent_dma_mask;
  26         else
  27                 end = (1ULL << 32) - 1;
  28
  29         ret = acpi_dma_get_range(dev, &map);
  30         if (!ret && map) {
  31                 end = dma_range_map_max(map);
  32                 dev->dma_range_map = map;
  33         }
  34
  35         if (ret == -ENODEV)
  36                 ret = iort_dma_get_ranges(dev, &end);
  37         if (!ret) {
  38                 /*
  39                  * Limit coherent and dma mask based on size retrieved from
  40                  * firmware.
  41                  */
  42                 mask = DMA_BIT_MASK(ilog2(end) + 1);
  43                 dev->bus_dma_limit = end;
  44                 dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
  45                 *dev->dma_mask = min(*dev->dma_mask, mask);
  46         }
  47 }