ACPI: arm64: Move DMA setup operations out of IORT

Extract generic DMA setup code out of IORT, so it can be reused by VIOT.
Keep it in drivers/acpi/arm64 for now, since it could break x86
platforms that haven't run this code so far, if they have invalid
tables.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20210618152059.1194210-2-jean-philippe@linaro.org
Signed-off-by: Joerg Roedel <jroedel@suse.de>

3 files changed, 59 insertions, 46 deletions

diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
index 6ff50f4ed947..66acbe77f46e 100644
--- a/drivers/acpi/arm64/Makefile
+++ b/drivers/acpi/arm64/Makefile
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_ACPI_IORT) 	+= iort.o
 obj-$(CONFIG_ACPI_GTDT) 	+= gtdt.o
+obj-y				+= dma.o
diff --git a/drivers/acpi/arm64/dma.c b/drivers/acpi/arm64/dma.c
new file mode 100644
index 000000000000..f16739ad3cc0
--- /dev/null
+++ b/drivers/acpi/arm64/dma.c
@@ -0,0 +1,50 @@
+// 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, u64 *dma_addr, u64 *dma_size)
+{
+	int ret;
+	u64 end, mask;
+	u64 dmaaddr = 0, size = 0, offset = 0;
+
+	/*
+	 * 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, &dmaaddr, &offset, &size);
+	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;
+		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!" : "");
+}
diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
index 3912a1f6058e..a940be1cf2af 100644
--- a/drivers/acpi/arm64/iort.c
+++ b/drivers/acpi/arm64/iort.c
@@ -1144,56 +1144,18 @@ static int rc_dma_get_range(struct device *dev, u64 *size)
 }
 
 /**
- * iort_dma_setup() - Set-up device DMA parameters.
+ * iort_dma_get_ranges() - Look up DMA addressing limit for the device
+ * @dev: device to lookup
+ * @size: DMA range size result pointer
  *
- * @dev: device to configure
- * @dma_addr: device DMA address result pointer
- * @dma_size: DMA range size result pointer
+ * Return: 0 on success, an error otherwise.
  */
-void iort_dma_setup(struct device *dev, u64 *dma_addr, u64 *dma_size)
+int iort_dma_get_ranges(struct device *dev, u64 *size)
 {
-	u64 end, mask, dmaaddr = 0, size = 0, offset = 0;
-	int ret;
-
-	/*
-	 * 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);
+	if (dev_is_pci(dev))
+		return rc_dma_get_range(dev, size);
 	else
-		size = 1ULL << 32;
-
-	ret = acpi_dma_get_range(dev, &dmaaddr, &offset, &size);
-	if (ret == -ENODEV)
-		ret = dev_is_pci(dev) ? rc_dma_get_range(dev, &size)
-				      : nc_dma_get_range(dev, &size);
-
-	if (!ret) {
-		/*
-		 * Limit coherent and dma mask based on size retrieved from
-		 * firmware.
-		 */
-		end = dmaaddr + 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!" : "");
+		return nc_dma_get_range(dev, size);
 }
 
 static void __init acpi_iort_register_irq(int hwirq, const char *name,