+Lorenzo On 04/10/16 18:03, Sricharan R wrote: > 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. > > Signed-off-by: Sricharan R <[email protected]> > --- > drivers/base/dd.c | 10 ++++++++++ > drivers/base/dma-mapping.c | 11 +++++++++++ > drivers/of/platform.c | 4 ---- > drivers/pci/probe.c | 5 +---- > include/linux/dma-mapping.h | 3 +++ > 5 files changed, 25 insertions(+), 8 deletions(-) > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > index 16688f5..cfebd48 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> > @@ -353,6 +354,10 @@ static int really_probe(struct device *dev, struct > device_driver *drv) > 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)); > @@ -395,6 +400,8 @@ static int really_probe(struct device *dev, struct > device_driver *drv) > 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); > @@ -780,6 +787,9 @@ static void __device_release_driver(struct device *dev) > dev->bus->remove(dev); > else if (drv->remove) > drv->remove(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 d799662..54e87f5 100644 > --- a/drivers/base/dma-mapping.c > +++ b/drivers/base/dma-mapping.c > @@ -10,6 +10,7 @@ > #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> > > @@ -166,6 +167,16 @@ void dmam_free_noncoherent(struct device *dev, size_t > size, void *vaddr, > } > EXPORT_SYMBOL(dmam_free_noncoherent); > > +int dma_configure(struct device *dev) > +{ > + return of_dma_configure(dev, dev->of_node); > +} > + > +void dma_deconfigure(struct device *dev) > +{ > + of_dma_deconfigure(dev); > +} > + > #ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT > > static void dmam_coherent_decl_release(struct device *dev, void *res) > diff --git a/drivers/of/platform.c b/drivers/of/platform.c > index 9cb7090..adbd77c 100644 > --- a/drivers/of/platform.c > +++ b/drivers/of/platform.c > @@ -181,11 +181,9 @@ static struct platform_device > *of_platform_device_create_pdata( > > dev->dev.bus = &platform_bus_type; > dev->dev.platform_data = platform_data; > - of_dma_configure(&dev->dev, dev->dev.of_node); > of_msi_configure(&dev->dev, dev->dev.of_node); > > if (of_device_add(dev) != 0) { > - of_dma_deconfigure(&dev->dev); > platform_device_put(dev); > goto err_clear_flag; > } > @@ -242,7 +240,6 @@ static struct amba_device *of_amba_device_create(struct > device_node *node, > dev_set_name(&dev->dev, "%s", bus_id); > else > of_device_make_bus_id(&dev->dev); > - of_dma_configure(&dev->dev, dev->dev.of_node); > > /* Allow the HW Peripheral ID to be overridden */ > prop = of_get_property(node, "arm,primecell-periphid", NULL); > @@ -536,7 +533,6 @@ static int of_platform_device_destroy(struct device *dev, > void *data) > amba_device_unregister(to_amba_device(dev)); > #endif > > - of_dma_deconfigure(dev); > of_node_clear_flag(dev->of_node, OF_POPULATED); > of_node_clear_flag(dev->of_node, OF_POPULATED_BUS); > return 0; > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 93f280d..85c9553 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1724,10 +1724,7 @@ static void pci_dma_configure(struct pci_dev *dev) > { > struct device *bridge = pci_get_host_bridge_device(dev); > > - if (IS_ENABLED(CONFIG_OF) && > - bridge->parent && bridge->parent->of_node) { > - of_dma_configure(&dev->dev, bridge->parent->of_node); > - } else if (has_acpi_companion(bridge)) { > + 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);
It seems a bit awkward leaving pci_dma_configure here, doing DMA configuration at device add, after we've allegedly moved DMA configuration to driver probe. Lorenzo, do you foresee any issues if this probe-time of_dma_configure() path were to also multiplex acpi_dma_configure() in future, such that everything would be back in the same place eventually? Conversely, is there actually any issue with leaving pci_dma_configure() unchanged, and simply moving the call from pci_device_add() into dma_configure()? Robin. > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index 66533e1..2766dbe 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -656,6 +656,9 @@ dma_mark_declared_memory_occupied(struct device *dev, > } > #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */ > > +int dma_configure(struct device *dev); > +void dma_deconfigure(struct device *dev); > + > /* > * Managed DMA API > */ > _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
