dma-mapping: move dma configuration to bus infrastructure

ACPI/OF support for configuration of DMA is a bus specific aspect, and
thus should be configured by the bus. Introduces a 'dma_configure' bus
method so that busses can control their DMA capabilities.

Also update the PCI, Platform, ACPI and host1x buses to use the new
method.

Suggested-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Nipun Gupta <[e-mail]>
Acked-by: Bjorn Helgaas <[e-mail]> # PCI parts
Acked-by: Thierry Reding <[e-mail]>
Reviewed-by: Greg Kroah-Hartman <[e-mail]>
[hch: simplified host1x_dma_configure based on a comment from Thierry,
rewrote changelog]
Signed-off-by: Christoph Hellwig <[e-mail]>

drivers/amba/bus.c

···
 #include <linux/sizes.h>
 #include <linux/limits.h>
 #include <linux/clk/clk-conf.h>
+#include <linux/platform_device.h>
 
 #include <asm/irq.h>
 
···
 /*
  * Primecells are part of the Advanced Microcontroller Bus Architecture,
  * so we call the bus "amba".
+ * DMA configuration for platform and AMBA bus is same. So here we reuse
+ * platform's DMA config routine.
  */
 struct bus_type amba_bustype = {
 	.name		= "amba",
 	.dev_groups	= amba_dev_groups,
 	.match		= amba_match,
 	.uevent		= amba_uevent,
+	.dma_configure	= platform_dma_configure,
 	.pm		= &amba_pm,
 	.force_dma	= true,
 };

drivers/base/dma-mapping.c

···
 #endif
 
 /*
- * Common configuration to enable DMA API use for a device
+ * enables DMA API use for a device
  */
-#include <linux/pci.h>
-
 int dma_configure(struct device *dev)
 {
-	struct device *bridge = NULL, *dma_dev = dev;
-	enum dev_dma_attr attr;
-	int ret = 0;
-
-	if (dev_is_pci(dev)) {
-		bridge = pci_get_host_bridge_device(to_pci_dev(dev));
-		dma_dev = bridge;
-		if (IS_ENABLED(CONFIG_OF) && dma_dev->parent &&
-		    dma_dev->parent->of_node)
-			dma_dev = dma_dev->parent;
-	}
-
-	if (dma_dev->of_node) {
-		ret = of_dma_configure(dev, dma_dev->of_node);
-	} else if (has_acpi_companion(dma_dev)) {
-		attr = acpi_get_dma_attr(to_acpi_device_node(dma_dev->fwnode));
-		if (attr != DEV_DMA_NOT_SUPPORTED)
-			ret = acpi_dma_configure(dev, attr);
-	}
-
-	if (bridge)
-		pci_put_host_bridge_device(bridge);
-
-	return ret;
+	if (dev->bus->dma_configure)
+		return dev->bus->dma_configure(dev);
+	return 0;
 }
 
 void dma_deconfigure(struct device *dev)

drivers/base/platform.c

···
 
 #endif /* CONFIG_HIBERNATE_CALLBACKS */
 
+int platform_dma_configure(struct device *dev)
+{
+	enum dev_dma_attr attr;
+	int ret = 0;
+
+	if (dev->of_node) {
+		ret = of_dma_configure(dev, dev->of_node);
+	} else if (has_acpi_companion(dev)) {
+		attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
+		if (attr != DEV_DMA_NOT_SUPPORTED)
+			ret = acpi_dma_configure(dev, attr);
+	}
+
+	return ret;
+}
+
 static const struct dev_pm_ops platform_dev_pm_ops = {
 	.runtime_suspend = pm_generic_runtime_suspend,
 	.runtime_resume = pm_generic_runtime_resume,
···
 	.dev_groups	= platform_dev_groups,
 	.match		= platform_match,
 	.uevent		= platform_uevent,
+	.dma_configure	= platform_dma_configure,
 	.pm		= &platform_dev_pm_ops,
 	.force_dma	= true,
 };

drivers/gpu/host1x/bus.c

···
 	return strcmp(dev_name(dev), drv->name) == 0;
 }
 
+static int host1x_dma_configure(struct device *dev)
+{
+	return of_dma_configure(dev, dev->of_node);
+}
+
 static const struct dev_pm_ops host1x_device_pm_ops = {
 	.suspend = pm_generic_suspend,
 	.resume = pm_generic_resume,
···
 struct bus_type host1x_bus_type = {
 	.name = "host1x",
 	.match = host1x_device_match,
+	.dma_configure	= host1x_dma_configure,
 	.pm = &host1x_device_pm_ops,
 	.force_dma = true,
 };

drivers/pci/pci-driver.c

···
 #include <linux/pm_runtime.h>
 #include <linux/suspend.h>
 #include <linux/kexec.h>
+#include <linux/of_device.h>
+#include <linux/acpi.h>
 #include "pci.h"
 #include "pcie/portdrv.h"
 
···
 	return pci_num_vf(to_pci_dev(dev));
 }
 
+/**
+ * pci_dma_configure - Setup DMA configuration
+ * @dev: ptr to dev structure
+ *
+ * Function to update PCI devices's DMA configuration using the same
+ * info from the OF node or ACPI node of host bridge's parent (if any).
+ */
+static int pci_dma_configure(struct device *dev)
+{
+	struct device *bridge;
+	int ret = 0;
+
+	bridge = pci_get_host_bridge_device(to_pci_dev(dev));
+
+	if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
+	    bridge->parent->of_node) {
+		ret = of_dma_configure(dev, bridge->parent->of_node);
+	} else if (has_acpi_companion(bridge)) {
+		struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
+		enum dev_dma_attr attr = acpi_get_dma_attr(adev);
+
+		if (attr != DEV_DMA_NOT_SUPPORTED)
+			ret = acpi_dma_configure(dev, attr);
+	}
+
+	pci_put_host_bridge_device(bridge);
+	return ret;
+}
+
 struct bus_type pci_bus_type = {
 	.name		= "pci",
 	.match		= pci_bus_match,
···
 	.drv_groups	= pci_drv_groups,
 	.pm		= PCI_PM_OPS_PTR,
 	.num_vf		= pci_bus_num_vf,
+	.dma_configure	= pci_dma_configure,
 	.force_dma	= true,
 };
 EXPORT_SYMBOL(pci_bus_type);

include/linux/device.h

···
  * @resume:	Called to bring a device on this bus out of sleep mode.
  * @num_vf:	Called to find out how many virtual functions a device on this
  *		bus supports.
+ * @dma_configure:	Called to setup DMA configuration on a device on
+			this bus.
  * @pm:		Power management operations of this bus, callback the specific
  *		device driver's pm-ops.
  * @iommu_ops:  IOMMU specific operations for this bus, used to attach IOMMU
···
 	int (*resume)(struct device *dev);
 
 	int (*num_vf)(struct device *dev);
+
+	int (*dma_configure)(struct device *dev);
 
 	const struct dev_pm_ops *pm;
 

include/linux/platform_device.h

···
 #define platform_pm_restore		NULL
 #endif
 
+extern int platform_dma_configure(struct device *dev);
+
 #ifdef CONFIG_PM_SLEEP
 #define USE_PLATFORM_PM_SLEEP_OPS \
 	.suspend = platform_pm_suspend, \