Hi Lorenzo, >-----Original Message----- >From: linux-arm-msm-owner@xxxxxxxxxxxxxxx [mailto:linux-arm-msm-owner@xxxxxxxxxxxxxxx] On Behalf Of Lorenzo Pieralisi >Sent: Thursday, October 27, 2016 4:19 PM >To: Sricharan <sricharan@xxxxxxxxxxxxxx> >Cc: 'Robin Murphy' <robin.murphy@xxxxxxx>; will.deacon@xxxxxxx; joro@xxxxxxxxxx; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux- >arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx; laurent.pinchart@xxxxxxxxxxxxxxxx; >m.szyprowski@xxxxxxxxxxx; tfiga@xxxxxxxxxxxx; srinivas.kandagatla@xxxxxxxxxx >Subject: Re: [PATCH V3 4/8] drivers: platform: Configure dma operations at probe time > >On Wed, Oct 26, 2016 at 08:34:59PM +0530, Sricharan wrote: >> Hi Robin, >> >> >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 <sricharan@xxxxxxxxxxxxxx> >> >> --- >> >> 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()? >> >> Ya i removed only the CONFIG_OF part out of this, and was hoping that >> the acpi configure can also be called from the dma_configure during >> probe later. I did not have an ACPI based platform though. As you >> said, if that looks right to the ACPI world, it can be moved out from >> here. I can try mergin series (after fixing the vfio errors part) with >> the ACPI IO port and see how it behaves. > >I do not expect any issue from this change, as long as, as Robin said, >it is done consistently which means that I am not ok with this patch >as it stands (ie you should defer pci_dma_configure() in its entirety, >not just the DT bits, which obviously requires some ACPI testing too). > >CC me in please in the next posting since this affects the ACPI probing >path too, we have to coordinate this series with my ACPI IORT SMMU >enablement patches: > >https://lkml.org/lkml/2016/10/18/506 Ok thanks, i will have you in looped for the V4 i am posting and we can have it tested on ACPI as well. Regards, Sricharan -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
