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Diffstat (limited to 'drivers/acpi/arm64/dma.c')
-rw-r--r--drivers/acpi/arm64/dma.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/drivers/acpi/arm64/dma.c b/drivers/acpi/arm64/dma.c
new file mode 100644
index 0000000000..93d796531a
--- /dev/null
+++ b/drivers/acpi/arm64/dma.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/acpi.h>
+#include <linux/acpi_iort.h>
+#include <linux/device.h>
+#include <linux/dma-direct.h>
+
+void acpi_arch_dma_setup(struct device *dev)
+{
+ int ret;
+ u64 end, mask;
+ u64 size = 0;
+ const struct bus_dma_region *map = NULL;
+
+ /*
+ * If @dev is expected to be DMA-capable then the bus code that created
+ * it should have initialised its dma_mask pointer by this point. For
+ * now, we'll continue the legacy behaviour of coercing it to the
+ * coherent mask if not, but we'll no longer do so quietly.
+ */
+ if (!dev->dma_mask) {
+ dev_warn(dev, "DMA mask not set\n");
+ dev->dma_mask = &dev->coherent_dma_mask;
+ }
+
+ if (dev->coherent_dma_mask)
+ size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
+ else
+ size = 1ULL << 32;
+
+ ret = acpi_dma_get_range(dev, &map);
+ if (!ret && map) {
+ const struct bus_dma_region *r = map;
+
+ for (end = 0; r->size; r++) {
+ if (r->dma_start + r->size - 1 > end)
+ end = r->dma_start + r->size - 1;
+ }
+
+ size = end + 1;
+ dev->dma_range_map = map;
+ }
+
+ if (ret == -ENODEV)
+ ret = iort_dma_get_ranges(dev, &size);
+ if (!ret) {
+ /*
+ * Limit coherent and dma mask based on size retrieved from
+ * firmware.
+ */
+ end = size - 1;
+ mask = DMA_BIT_MASK(ilog2(end) + 1);
+ dev->bus_dma_limit = end;
+ dev->coherent_dma_mask = min(dev->coherent_dma_mask, mask);
+ *dev->dma_mask = min(*dev->dma_mask, mask);
+ }
+}