ACPI: scan: Support multiple DMA windows with different offsets

In DT systems configurations, of_dma_get_range() returns struct
bus_dma_region DMA regions; they are used to set-up devices
DMA windows with different offset available for translation between DMA
address and CPU address.

In ACPI systems configuration, acpi_dma_get_range() does not return
DMA regions yet and that precludes setting up the dev->dma_range_map
pointer and therefore DMA regions with multiple offsets.

Update acpi_dma_get_range() to return struct bus_dma_region
DMA regions like of_dma_get_range() does.

After updating acpi_dma_get_range(), acpi_arch_dma_setup() is changed for
ARM64, where the original dma_addr and size are removed as these
arguments are now redundant, and pass 0 and U64_MAX for dma_base
and size of arch_setup_dma_ops; this is a simplification consistent
with what other ACPI architectures also pass to iommu_setup_dma_ops().

Reviewed-by: Robin Murphy <[e-mail]>
Signed-off-by: Jianmin Lv <[e-mail]>
Reviewed-by: Lorenzo Pieralisi <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/arm64/dma.c

···
 #include <linux/device.h>
 #include <linux/dma-direct.h>
 
-void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
+void acpi_arch_dma_setup(struct device *dev)
 {
 	int ret;
 	u64 end, mask;
-	u64 dmaaddr = 0, size = 0, offset = 0;
+	u64 size = 0;
+	const struct bus_dma_region *map = NULL;
 
 	/*
 	 * If @dev is expected to be DMA-capable then the bus code that created
···
 	else
 		size = 1ULL << 32;
 
-	ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
+	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 = dmaaddr + size - 1;
+		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);
 	}
-
-	*dma_addr = dmaaddr;
-	*dma_size = size;
-
-	ret = dma_direct_set_offset(dev, dmaaddr + offset, dmaaddr, size);
-
-	dev_dbg(dev, "dma_offset(%#08llx)%s\n", offset, ret ? " failed!" : "");
 }

drivers/acpi/scan.c

···
 #include <linux/platform_data/x86/apple.h>
 #include <linux/pgtable.h>
 #include <linux/crc32.h>
+#include <linux/dma-direct.h>
 
 #include "internal.h"
 
···
  * acpi_dma_get_range() - Get device DMA parameters.
  *
  * @dev: device to configure
- * @dma_addr: pointer device DMA address result
- * @offset: pointer to the DMA offset result
- * @size: pointer to DMA range size result
+ * @map: pointer to DMA ranges result
  *
- * Evaluate DMA regions and return respectively DMA region start, offset
- * and size in dma_addr, offset and size on parsing success; it does not
- * update the passed in values on failure.
+ * Evaluate DMA regions and return pointer to DMA regions on
+ * parsing success; it does not update the passed in values on failure.
  *
  * Return 0 on success, < 0 on failure.
  */
-int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
-		       u64 *size)
+int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
 {
 	struct acpi_device *adev;
 	LIST_HEAD(list);
 	struct resource_entry *rentry;
 	int ret;
 	struct device *dma_dev = dev;
-	u64 len, dma_start = U64_MAX, dma_end = 0, dma_offset = 0;
+	struct bus_dma_region *r;
 
 	/*
 	 * Walk the device tree chasing an ACPI companion with a _DMA
···
 
 	ret = acpi_dev_get_dma_resources(adev, &list);
 	if (ret > 0) {
-		list_for_each_entry(rentry, &list, node) {
-			if (dma_offset && rentry->offset != dma_offset) {
-				ret = -EINVAL;
-				dev_warn(dma_dev, "Can't handle multiple windows with different offsets\n");
-				goto out;
-			}
-			dma_offset = rentry->offset;
-
-			/* Take lower and upper limits */
-			if (rentry->res->start < dma_start)
-				dma_start = rentry->res->start;
-			if (rentry->res->end > dma_end)
-				dma_end = rentry->res->end;
-		}
-
-		if (dma_start >= dma_end) {
-			ret = -EINVAL;
-			dev_dbg(dma_dev, "Invalid DMA regions configuration\n");
+		r = kcalloc(ret + 1, sizeof(*r), GFP_KERNEL);
+		if (!r) {
+			ret = -ENOMEM;
 			goto out;
 		}
 
-		*dma_addr = dma_start - dma_offset;
-		len = dma_end - dma_start;
-		*size = max(len, len + 1);
-		*offset = dma_offset;
+		list_for_each_entry(rentry, &list, node) {
+			if (rentry->res->start >= rentry->res->end) {
+				kfree(r);
+				ret = -EINVAL;
+				dev_dbg(dma_dev, "Invalid DMA regions configuration\n");
+				goto out;
+			}
+
+			r->cpu_start = rentry->res->start;
+			r->dma_start = rentry->res->start - rentry->offset;
+			r->size = resource_size(rentry->res);
+			r->offset = rentry->offset;
+			r++;
+		}
+
+		*map = r;
 	}
  out:
 	acpi_dev_free_resource_list(&list);
···
 			  const u32 *input_id)
 {
 	const struct iommu_ops *iommu;
-	u64 dma_addr = 0, size = 0;
 
 	if (attr == DEV_DMA_NOT_SUPPORTED) {
 		set_dma_ops(dev, &dma_dummy_ops);
 		return 0;
 	}
 
-	acpi_arch_dma_setup(dev, &dma_addr, &size);
+	acpi_arch_dma_setup(dev);
 
 	iommu = acpi_iommu_configure_id(dev, input_id);
 	if (PTR_ERR(iommu) == -EPROBE_DEFER)
 		return -EPROBE_DEFER;
 
-	arch_setup_dma_ops(dev, dma_addr, size,
+	arch_setup_dma_ops(dev, 0, U64_MAX,
 				iommu, attr == DEV_DMA_COHERENT);
 
 	return 0;

include/acpi/acpi_bus.h

···
 int acpi_iommu_fwspec_init(struct device *dev, u32 id,
 			   struct fwnode_handle *fwnode,
 			   const struct iommu_ops *ops);
-int acpi_dma_get_range(struct device *dev, u64 *dma_addr, u64 *offset,
-		       u64 *size);
+int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map);
 int acpi_dma_configure_id(struct device *dev, enum dev_dma_attr attr,
 			   const u32 *input_id);
 static inline int acpi_dma_configure(struct device *dev,

include/linux/acpi.h

···
 
 #ifdef CONFIG_ARM64
 void acpi_numa_gicc_affinity_init(struct acpi_srat_gicc_affinity *pa);
-void acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size);
+void acpi_arch_dma_setup(struct device *dev);
 #else
 static inline void
 acpi_numa_gicc_affinity_init(struct acpi_srat_gicc_affinity *pa) { }
 static inline void
-acpi_arch_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size) { }
+acpi_arch_dma_setup(struct device *dev) { }
 #endif
 
 int acpi_numa_memory_affinity_init (struct acpi_srat_mem_affinity *ma);
···
 	return DEV_DMA_NOT_SUPPORTED;
 }
 
-static inline int acpi_dma_get_range(struct device *dev, u64 *dma_addr,
-				     u64 *offset, u64 *size)
+static inline int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
 {
 	return -ENODEV;
 }