of/acpi: Configure dma operations at probe time for platform/amba/pci bus devices

Configuring DMA ops at probe time will allow deferring device probe when
the IOMMU isn't available yet. The dma_configure for the device is
now called from the generic device_attach callback just before the
bus/driver probe is called. This way, configuring the DMA ops for the
device would be called at the same place for all bus_types, hence the
deferred probing mechanism should work for all buses as well.

pci_bus_add_devices    (platform/amba)(_device_create/driver_register)
       |                         |
pci_bus_add_device     (device_add/driver_register)
       |                         |
device_attach           device_initial_probe
       |                         |
__device_attach_driver    __device_attach_driver
       |
driver_probe_device
       |
really_probe
       |
dma_configure

Similarly on the device/driver_unregister path __device_release_driver is
called which inturn calls dma_deconfigure.

This patch changes the dma ops configuration to probe time for
both OF and ACPI based platform/amba/pci bus devices.

Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> (drivers/pci part)
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sricharan R <sricharan@codeaurora.org>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

2 files changed, 49 insertions, 0 deletions

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index a1fbf55c4d3a..4882f06d12df 100644
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -19,6 +19,7 @@
 
 #include <linux/device.h>
 #include <linux/delay.h>
+#include <linux/dma-mapping.h>
 #include <linux/module.h>
 #include <linux/kthread.h>
 #include <linux/wait.h>
@@ -356,6 +357,10 @@ re_probe:
 	if (ret)
 		goto pinctrl_bind_failed;
 
+	ret = dma_configure(dev);
+	if (ret)
+		goto dma_failed;
+
 	if (driver_sysfs_add(dev)) {
 		printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
 			__func__, dev_name(dev));
@@ -417,6 +422,8 @@ re_probe:
 	goto done;
 
 probe_failed:
+	dma_deconfigure(dev);
+dma_failed:
 	if (dev->bus)
 		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
 					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
@@ -826,6 +833,8 @@ static void __device_release_driver(struct device *dev, struct device *parent)
 			drv->remove(dev);
 
 		device_links_driver_cleanup(dev);
+		dma_deconfigure(dev);
+
 		devres_release_all(dev);
 		dev->driver = NULL;
 		dev_set_drvdata(dev, NULL);
diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
index efd71cf4fdea..449b948c7427 100644
--- a/drivers/base/dma-mapping.c
+++ b/drivers/base/dma-mapping.c
@@ -7,9 +7,11 @@
  * This file is released under the GPLv2.
  */
 
+#include <linux/acpi.h>
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
 #include <linux/gfp.h>
+#include <linux/of_device.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 
@@ -341,3 +343,41 @@ void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
 	vunmap(cpu_addr);
 }
 #endif
+
+/*
+ * Common configuration to enable 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;
+
+	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) {
+		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)
+			acpi_dma_configure(dev, attr);
+	}
+
+	if (bridge)
+		pci_put_host_bridge_device(bridge);
+
+	return 0;
+}
+
+void dma_deconfigure(struct device *dev)
+{
+	of_dma_deconfigure(dev);
+	acpi_dma_deconfigure(dev);
+}